#!/usr/bin/python -O
# Copyright 1999-2006 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2
# $Id$

import array
from collections import deque
import fcntl
import formatter
import logging
import pwd
import select
import shlex
import shutil
import signal
import sys
import textwrap
import urlparse
import weakref
import gc
import os, stat
import platform

try:
	import portage
except ImportError:
	from os import path as osp
	sys.path.insert(0, osp.join(osp.dirname(osp.dirname(osp.realpath(__file__))), "pym"))
	import portage

from portage import digraph
from portage.const import NEWS_LIB_PATH

import _emerge.help
import portage.xpak, commands, errno, re, socket, time
from portage.output import blue, bold, colorize, darkblue, darkgreen, darkred, green, \
	nc_len, red, teal, turquoise, xtermTitle, \
	xtermTitleReset, yellow
from portage.output import create_color_func
good = create_color_func("GOOD")
bad = create_color_func("BAD")
# white looks bad on terminals with white background
from portage.output import bold as white

import portage.elog
import portage.dep
portage.dep._dep_check_strict = True
import portage.util
import portage.locks
import portage.exception
from portage.data import secpass
from portage.elog.messages import eerror
from portage.util import normalize_path as normpath
from portage.util import cmp_sort_key, writemsg, writemsg_level
from portage.sets import load_default_config, SETPREFIX
from portage.sets.base import InternalPackageSet

from itertools import chain, izip

try:
	import cPickle as pickle
except ImportError:
	import pickle

try:
	from cStringIO import StringIO
except ImportError:
	from StringIO import StringIO

class stdout_spinner(object):
	scroll_msgs = [
		"Gentoo Rocks ("+platform.system()+")",
		"Thank you for using Gentoo. :)",
		"Are you actually trying to read this?",
		"How many times have you stared at this?",
		"We are generating the cache right now",
		"You are paying too much attention.",
		"A theory is better than its explanation.",
		"Phasers locked on target, Captain.",
		"Thrashing is just virtual crashing.",
		"To be is to program.",
		"Real Users hate Real Programmers.",
		"When all else fails, read the instructions.",
		"Functionality breeds Contempt.",
		"The future lies ahead.",
		"3.1415926535897932384626433832795028841971694",
		"Sometimes insanity is the only alternative.",
		"Inaccuracy saves a world of explanation.",
	]

	twirl_sequence = "/-\\|/-\\|/-\\|/-\\|\\-/|\\-/|\\-/|\\-/|"

	def __init__(self):
		self.spinpos = 0
		self.update = self.update_twirl
		self.scroll_sequence = self.scroll_msgs[
			int(time.time() * 100) % len(self.scroll_msgs)]
		self.last_update = 0
		self.min_display_latency = 0.05

	def _return_early(self):
		"""
		Flushing ouput to the tty too frequently wastes cpu time. Therefore,
		each update* method should return without doing any output when this
		method returns True.
		"""
		cur_time = time.time()
		if cur_time - self.last_update < self.min_display_latency:
			return True
		self.last_update = cur_time
		return False

	def update_basic(self):
		self.spinpos = (self.spinpos + 1) % 500
		if self._return_early():
			return
		if (self.spinpos % 100) == 0:
			if self.spinpos == 0:
				sys.stdout.write(". ")
			else:
				sys.stdout.write(".")
		sys.stdout.flush()

	def update_scroll(self):
		if self._return_early():
			return
		if(self.spinpos >= len(self.scroll_sequence)):
			sys.stdout.write(darkgreen(" \b\b\b" + self.scroll_sequence[
				len(self.scroll_sequence) - 1 - (self.spinpos % len(self.scroll_sequence))]))
		else:
			sys.stdout.write(green("\b " + self.scroll_sequence[self.spinpos]))
		sys.stdout.flush()
		self.spinpos = (self.spinpos + 1) % (2 * len(self.scroll_sequence))

	def update_twirl(self):
		self.spinpos = (self.spinpos + 1) % len(self.twirl_sequence)
		if self._return_early():
			return
		sys.stdout.write("\b\b " + self.twirl_sequence[self.spinpos])
		sys.stdout.flush()

	def update_quiet(self):
		return

def userquery(prompt, responses=None, colours=None):
	"""Displays a prompt and a set of responses, then waits for a response
	which is checked against the responses and the first to match is
	returned.  An empty response will match the first value in responses.  The
	input buffer is *not* cleared prior to the prompt!

	prompt: a String.
	responses: a List of Strings.
	colours: a List of Functions taking and returning a String, used to
	process the responses for display. Typically these will be functions
	like red() but could be e.g. lambda x: "DisplayString".
	If responses is omitted, defaults to ["Yes", "No"], [green, red].
	If only colours is omitted, defaults to [bold, ...].

	Returns a member of the List responses. (If called without optional
	arguments, returns "Yes" or "No".)
	KeyboardInterrupt is converted to SystemExit to avoid tracebacks being
	printed."""
	if responses is None:
		responses = ["Yes", "No"]
		colours = [
			create_color_func("PROMPT_CHOICE_DEFAULT"),
			create_color_func("PROMPT_CHOICE_OTHER")
		]
	elif colours is None:
		colours=[bold]
	colours=(colours*len(responses))[:len(responses)]
	print bold(prompt),
	try:
		while True:
			response=raw_input("["+"/".join([colours[i](responses[i]) for i in range(len(responses))])+"] ")
			for key in responses:
				# An empty response will match the first value in responses.
				if response.upper()==key[:len(response)].upper():
					return key
			print "Sorry, response '%s' not understood." % response,
	except (EOFError, KeyboardInterrupt):
		print "Interrupted."
		sys.exit(1)

actions = frozenset([
"clean", "config", "depclean",
"info", "list-sets", "metadata",
"prune", "regen",  "search",
"sync",  "unmerge", "version",
])
options=[
"--ask",          "--alphabetical",
"--buildpkg",     "--buildpkgonly",
"--changelog",    "--columns",
"--complete-graph",
"--debug",        "--deep",
"--digest",
"--emptytree",
"--fetchonly",    "--fetch-all-uri",
"--getbinpkg",    "--getbinpkgonly",
"--help",         "--ignore-default-opts",
"--keep-going",
"--noconfmem",
"--newuse",       "--nocolor",
"--nodeps",       "--noreplace",
"--nospinner",    "--oneshot",
"--onlydeps",     "--pretend",
"--quiet",        "--resume",
"--searchdesc",   "--selective",
"--skipfirst",
"--tree",
"--update",
"--usepkg",       "--usepkgonly",
"--verbose",
]

shortmapping={
"1":"--oneshot",
"a":"--ask",
"b":"--buildpkg",  "B":"--buildpkgonly",
"c":"--clean",     "C":"--unmerge",
"d":"--debug",     "D":"--deep",
"e":"--emptytree",
"f":"--fetchonly", "F":"--fetch-all-uri",
"g":"--getbinpkg", "G":"--getbinpkgonly",
"h":"--help",
"k":"--usepkg",    "K":"--usepkgonly",
"l":"--changelog",
"n":"--noreplace", "N":"--newuse",
"o":"--onlydeps",  "O":"--nodeps",
"p":"--pretend",   "P":"--prune",
"q":"--quiet",
"s":"--search",    "S":"--searchdesc",
"t":"--tree",
"u":"--update",
"v":"--verbose",   "V":"--version"
}

def emergelog(xterm_titles, mystr, short_msg=None):
	if xterm_titles and short_msg:
		if "HOSTNAME" in os.environ:
			short_msg = os.environ["HOSTNAME"]+": "+short_msg
		xtermTitle(short_msg)
	try:
		file_path = "/var/log/emerge.log"
		mylogfile = open(file_path, "a")
		portage.util.apply_secpass_permissions(file_path,
			uid=portage.portage_uid, gid=portage.portage_gid,
			mode=0660)
		mylock = None
		try:
			mylock = portage.locks.lockfile(mylogfile)
			# seek because we may have gotten held up by the lock.
			# if so, we may not be positioned at the end of the file.
			mylogfile.seek(0, 2)
			mylogfile.write(str(time.time())[:10]+": "+mystr+"\n")
			mylogfile.flush()
		finally:
			if mylock:
				portage.locks.unlockfile(mylock)
			mylogfile.close()
	except (IOError,OSError,portage.exception.PortageException), e:
		if secpass >= 1:
			print >> sys.stderr, "emergelog():",e

def countdown(secs=5, doing="Starting"):
	if secs:
		print ">>> Waiting",secs,"seconds before starting..."
		print ">>> (Control-C to abort)...\n"+doing+" in: ",
		ticks=range(secs)
		ticks.reverse()
		for sec in ticks:
			sys.stdout.write(colorize("UNMERGE_WARN", str(sec+1)+" "))
			sys.stdout.flush()
			time.sleep(1)
		print

# formats a size given in bytes nicely
def format_size(mysize):
	if isinstance(mysize, basestring):
		return mysize
	if 0 != mysize % 1024:
		# Always round up to the next kB so that it doesn't show 0 kB when
		# some small file still needs to be fetched.
		mysize += 1024 - mysize % 1024
	mystr=str(mysize/1024)
	mycount=len(mystr)
	while (mycount > 3):
		mycount-=3
		mystr=mystr[:mycount]+","+mystr[mycount:]
	return mystr+" kB"


def getgccversion(chost):
	"""
	rtype: C{str}
	return:  the current in-use gcc version
	"""

	gcc_ver_command = 'gcc -dumpversion'
	gcc_ver_prefix = 'gcc-'

	gcc_not_found_error = red(
	"!!! No gcc found. You probably need to 'source /etc/profile'\n" +
	"!!! to update the environment of this terminal and possibly\n" +
	"!!! other terminals also.\n"
	)

	mystatus, myoutput = commands.getstatusoutput("gcc-config -c")
	if mystatus == os.EX_OK and myoutput.startswith(chost + "-"):
		return myoutput.replace(chost + "-", gcc_ver_prefix, 1)

	mystatus, myoutput = commands.getstatusoutput(
		chost + "-" + gcc_ver_command)
	if mystatus == os.EX_OK:
		return gcc_ver_prefix + myoutput

	mystatus, myoutput = commands.getstatusoutput(gcc_ver_command)
	if mystatus == os.EX_OK:
		return gcc_ver_prefix + myoutput

	portage.writemsg(gcc_not_found_error, noiselevel=-1)
	return "[unavailable]"

def getportageversion(portdir, target_root, profile, chost, vardb):
	profilever = "unavailable"
	if profile:
		realpath = os.path.realpath(profile)
		basepath   = os.path.realpath(os.path.join(portdir, "profiles"))
		if realpath.startswith(basepath):
			profilever = realpath[1 + len(basepath):]
		else:
			try:
				profilever = "!" + os.readlink(profile)
			except (OSError):
				pass
		del realpath, basepath

	libcver=[]
	libclist  = vardb.match("virtual/libc")
	libclist += vardb.match("virtual/glibc")
	libclist  = portage.util.unique_array(libclist)
	for x in libclist:
		xs=portage.catpkgsplit(x)
		if libcver:
			libcver+=","+"-".join(xs[1:])
		else:
			libcver="-".join(xs[1:])
	if libcver==[]:
		libcver="unavailable"

	gccver = getgccversion(chost)
	unameout=platform.release()+" "+platform.machine()

	return "Portage " + portage.VERSION +" ("+profilever+", "+gccver+", "+libcver+", "+unameout+")"

def create_depgraph_params(myopts, myaction):
	#configure emerge engine parameters
	#
	# self:      include _this_ package regardless of if it is merged.
	# selective: exclude the package if it is merged
	# recurse:   go into the dependencies
	# deep:      go into the dependencies of already merged packages
	# empty:     pretend nothing is merged
	# complete:  completely account for all known dependencies
	# remove:    build graph for use in removing packages
	myparams = set(["recurse"])

	if myaction == "remove":
		myparams.add("remove")
		myparams.add("complete")
		return myparams

	if "--update" in myopts or \
		"--newuse" in myopts or \
		"--reinstall" in myopts or \
		"--noreplace" in myopts:
		myparams.add("selective")
	if "--emptytree" in myopts:
		myparams.add("empty")
		myparams.discard("selective")
	if "--nodeps" in myopts:
		myparams.discard("recurse")
	if "--deep" in myopts:
		myparams.add("deep")
	if "--complete-graph" in myopts:
		myparams.add("complete")
	return myparams

# search functionality
class search(object):

	#
	# class constants
	#
	VERSION_SHORT=1
	VERSION_RELEASE=2

	#
	# public interface
	#
	def __init__(self, root_config, spinner, searchdesc,
		verbose, usepkg, usepkgonly):
		"""Searches the available and installed packages for the supplied search key.
		The list of available and installed packages is created at object instantiation.
		This makes successive searches faster."""
		self.settings = root_config.settings
		self.vartree = root_config.trees["vartree"]
		self.spinner = spinner
		self.verbose = verbose
		self.searchdesc = searchdesc
		self.root_config = root_config
		self.setconfig = root_config.setconfig
		self.matches = {"pkg" : []}
		self.mlen = 0

		def fake_portdb():
			pass
		self.portdb = fake_portdb
		for attrib in ("aux_get", "cp_all",
			"xmatch", "findname", "getFetchMap"):
			setattr(fake_portdb, attrib, getattr(self, "_"+attrib))

		self._dbs = []

		portdb = root_config.trees["porttree"].dbapi
		bindb = root_config.trees["bintree"].dbapi
		vardb = root_config.trees["vartree"].dbapi

		if not usepkgonly and portdb._have_root_eclass_dir:
			self._dbs.append(portdb)

		if (usepkg or usepkgonly) and bindb.cp_all():
			self._dbs.append(bindb)

		self._dbs.append(vardb)
		self._portdb = portdb

	def _cp_all(self):
		cp_all = set()
		for db in self._dbs:
			cp_all.update(db.cp_all())
		return list(sorted(cp_all))

	def _aux_get(self, *args, **kwargs):
		for db in self._dbs:
			try:
				return db.aux_get(*args, **kwargs)
			except KeyError:
				pass
		raise

	def _findname(self, *args, **kwargs):
		for db in self._dbs:
			if db is not self._portdb:
				# We don't want findname to return anything
				# unless it's an ebuild in a portage tree.
				# Otherwise, it's already built and we don't
				# care about it.
				continue
			func = getattr(db, "findname", None)
			if func:
				value = func(*args, **kwargs)
				if value:
					return value
		return None

	def _getFetchMap(self, *args, **kwargs):
		for db in self._dbs:
			func = getattr(db, "getFetchMap", None)
			if func:
				value = func(*args, **kwargs)
				if value:
					return value
		return {}

	def _visible(self, db, cpv, metadata):
		installed = db is self.vartree.dbapi
		built = installed or db is not self._portdb
		pkg_type = "ebuild"
		if installed:
			pkg_type = "installed"
		elif built:
			pkg_type = "binary"
		return visible(self.settings,
			Package(type_name=pkg_type, root_config=self.root_config,
			cpv=cpv, built=built, installed=installed, metadata=metadata))

	def _xmatch(self, level, atom):
		"""
		This method does not expand old-style virtuals because it
		is restricted to returning matches for a single ${CATEGORY}/${PN}
		and old-style virual matches unreliable for that when querying
		multiple package databases. If necessary, old-style virtuals
		can be performed on atoms prior to calling this method.
		"""
		cp = portage.dep_getkey(atom)
		if level == "match-all":
			matches = set()
			for db in self._dbs:
				if hasattr(db, "xmatch"):
					matches.update(db.xmatch(level, atom))
				else:
					matches.update(db.match(atom))
			result = list(x for x in matches if portage.cpv_getkey(x) == cp)
			db._cpv_sort_ascending(result)
		elif level == "match-visible":
			matches = set()
			for db in self._dbs:
				if hasattr(db, "xmatch"):
					matches.update(db.xmatch(level, atom))
				else:
					db_keys = list(db._aux_cache_keys)
					for cpv in db.match(atom):
						metadata = izip(db_keys,
							db.aux_get(cpv, db_keys))
						if not self._visible(db, cpv, metadata):
							continue
						matches.add(cpv)
			result = list(x for x in matches if portage.cpv_getkey(x) == cp)
			db._cpv_sort_ascending(result)
		elif level == "bestmatch-visible":
			result = None
			for db in self._dbs:
				if hasattr(db, "xmatch"):
					cpv = db.xmatch("bestmatch-visible", atom)
					if not cpv or portage.cpv_getkey(cpv) != cp:
						continue
					if not result or cpv == portage.best([cpv, result]):
						result = cpv
				else:
					db_keys = Package.metadata_keys
					# break out of this loop with highest visible
					# match, checked in descending order
					for cpv in reversed(db.match(atom)):
						if portage.cpv_getkey(cpv) != cp:
							continue
						metadata = izip(db_keys,
							db.aux_get(cpv, db_keys))
						if not self._visible(db, cpv, metadata):
							continue
						if not result or cpv == portage.best([cpv, result]):
							result = cpv
						break
		else:
			raise NotImplementedError(level)
		return result

	def execute(self,searchkey):
		"""Performs the search for the supplied search key"""
		match_category = 0
		self.searchkey=searchkey
		self.packagematches = []
		if self.searchdesc:
			self.searchdesc=1
			self.matches = {"pkg":[], "desc":[], "set":[]}
		else:
			self.searchdesc=0
			self.matches = {"pkg":[], "set":[]}
		print "Searching...   ",

		regexsearch = False
		if self.searchkey.startswith('%'):
			regexsearch = True
			self.searchkey = self.searchkey[1:]
		if self.searchkey.startswith('@'):
			match_category = 1
			self.searchkey = self.searchkey[1:]
		if regexsearch:
			self.searchre=re.compile(self.searchkey,re.I)
		else:
			self.searchre=re.compile(re.escape(self.searchkey), re.I)
		for package in self.portdb.cp_all():
			self.spinner.update()

			if match_category:
				match_string  = package[:]
			else:
				match_string  = package.split("/")[-1]

			masked=0
			if self.searchre.search(match_string):
				if not self.portdb.xmatch("match-visible", package):
					masked=1
				self.matches["pkg"].append([package,masked])
			elif self.searchdesc: # DESCRIPTION searching
				full_package = self.portdb.xmatch("bestmatch-visible", package)
				if not full_package:
					#no match found; we don't want to query description
					full_package = portage.best(
						self.portdb.xmatch("match-all", package))
					if not full_package:
						continue
					else:
						masked=1
				try:
					full_desc = self.portdb.aux_get(
						full_package, ["DESCRIPTION"])[0]
				except KeyError:
					print "emerge: search: aux_get() failed, skipping"
					continue
				if self.searchre.search(full_desc):
					self.matches["desc"].append([full_package,masked])

		self.sdict = self.setconfig.getSets()
		for setname in self.sdict:
			self.spinner.update()
			if match_category:
				match_string = setname
			else:
				match_string = setname.split("/")[-1]
			
			if self.searchre.search(match_string):
				self.matches["set"].append([setname, False])
			elif self.searchdesc:
				if self.searchre.search(
					self.sdict[setname].getMetadata("DESCRIPTION")):
					self.matches["set"].append([setname, False])
			
		self.mlen=0
		for mtype in self.matches:
			self.matches[mtype].sort()
			self.mlen += len(self.matches[mtype])

	def addCP(self, cp):
		if not self.portdb.xmatch("match-all", cp):
			return
		masked = 0
		if not self.portdb.xmatch("bestmatch-visible", cp):
			masked = 1
		self.matches["pkg"].append([cp, masked])
		self.mlen += 1

	def output(self):
		"""Outputs the results of the search."""
		print "\b\b  \n[ Results for search key : "+white(self.searchkey)+" ]"
		print "[ Applications found : "+white(str(self.mlen))+" ]"
		print " "
		vardb = self.vartree.dbapi
		for mtype in self.matches:
			for match,masked in self.matches[mtype]:
				full_package = None
				if mtype == "pkg":
					catpack = match
					full_package = self.portdb.xmatch(
						"bestmatch-visible", match)
					if not full_package:
						#no match found; we don't want to query description
						masked=1
						full_package = portage.best(
							self.portdb.xmatch("match-all",match))
				elif mtype == "desc":
					full_package = match
					match        = portage.cpv_getkey(match)
				elif mtype == "set":
					print green("*")+"  "+white(match)
					print "     ", darkgreen("Description:")+"  ", self.sdict[match].getMetadata("DESCRIPTION")
					print
				if full_package:
					try:
						desc, homepage, license = self.portdb.aux_get(
							full_package, ["DESCRIPTION","HOMEPAGE","LICENSE"])
					except KeyError:
						print "emerge: search: aux_get() failed, skipping"
						continue
					if masked:
						print green("*")+"  "+white(match)+" "+red("[ Masked ]")
					else:
						print green("*")+"  "+white(match)
					myversion = self.getVersion(full_package, search.VERSION_RELEASE)

					mysum = [0,0]
					file_size_str = None
					mycat = match.split("/")[0]
					mypkg = match.split("/")[1]
					mycpv = match + "-" + myversion
					myebuild = self.portdb.findname(mycpv)
					if myebuild:
						pkgdir = os.path.dirname(myebuild)
						from portage import manifest
						mf = manifest.Manifest(
							pkgdir, self.settings["DISTDIR"])
						try:
							uri_map = self.portdb.getFetchMap(mycpv)
						except portage.exception.InvalidDependString, e:
							file_size_str = "Unknown (%s)" % (e,)
							del e
						else:
							try:
								mysum[0] = mf.getDistfilesSize(uri_map)
							except KeyError, e:
								file_size_str = "Unknown (missing " + \
									"digest for %s)" % (e,)
								del e

					available = False
					for db in self._dbs:
						if db is not vardb and \
							db.cpv_exists(mycpv):
							available = True
							if not myebuild and hasattr(db, "bintree"):
								myebuild = db.bintree.getname(mycpv)
								try:
									mysum[0] = os.stat(myebuild).st_size
								except OSError:
									myebuild = None
							break

					if myebuild and file_size_str is None:
						mystr = str(mysum[0] / 1024)
						mycount = len(mystr)
						while (mycount > 3):
							mycount -= 3
							mystr = mystr[:mycount] + "," + mystr[mycount:]
						file_size_str = mystr + " kB"

					if self.verbose:
						if available:
							print "     ", darkgreen("Latest version available:"),myversion
						print "     ", self.getInstallationStatus(mycat+'/'+mypkg)
						if myebuild:
							print "      %s %s" % \
								(darkgreen("Size of files:"), file_size_str)
						print "     ", darkgreen("Homepage:")+"     ",homepage
						print "     ", darkgreen("Description:")+"  ",desc
						print "     ", darkgreen("License:")+"      ",license
						print
	#
	# private interface
	#
	def getInstallationStatus(self,package):
		installed_package = self.vartree.dep_bestmatch(package)
		result = ""
		version = self.getVersion(installed_package,search.VERSION_RELEASE)
		if len(version) > 0:
			result = darkgreen("Latest version installed:")+" "+version
		else:
			result = darkgreen("Latest version installed:")+" [ Not Installed ]"
		return result

	def getVersion(self,full_package,detail):
		if len(full_package) > 1:
			package_parts = portage.catpkgsplit(full_package)
			if detail == search.VERSION_RELEASE and package_parts[3] != 'r0':
				result = package_parts[2]+ "-" + package_parts[3]
			else:
				result = package_parts[2]
		else:
			result = ""
		return result

class RootConfig(object):
	"""This is used internally by depgraph to track information about a
	particular $ROOT."""

	pkg_tree_map = {
		"ebuild"    : "porttree",
		"binary"    : "bintree",
		"installed" : "vartree"
	}

	tree_pkg_map = {}
	for k, v in pkg_tree_map.iteritems():
		tree_pkg_map[v] = k

	def __init__(self, settings, trees, setconfig):
		self.trees = trees
		self.settings = settings
		self.iuse_implicit = tuple(sorted(settings._get_implicit_iuse()))
		self.root = self.settings["ROOT"]
		self.setconfig = setconfig
		self.sets = self.setconfig.getSets()
		self.visible_pkgs = PackageVirtualDbapi(self.settings)

def create_world_atom(pkg, args_set, root_config):
	"""Create a new atom for the world file if one does not exist.  If the
	argument atom is precise enough to identify a specific slot then a slot
	atom will be returned. Atoms that are in the system set may also be stored
	in world since system atoms can only match one slot while world atoms can
	be greedy with respect to slots.  Unslotted system packages will not be
	stored in world."""

	arg_atom = args_set.findAtomForPackage(pkg)
	if not arg_atom:
		return None
	cp = portage.dep_getkey(arg_atom)
	new_world_atom = cp
	sets = root_config.sets
	portdb = root_config.trees["porttree"].dbapi
	vardb = root_config.trees["vartree"].dbapi
	available_slots = set(portdb.aux_get(cpv, ["SLOT"])[0] \
		for cpv in portdb.match(cp))
	slotted = len(available_slots) > 1 or \
		(len(available_slots) == 1 and "0" not in available_slots)
	if not slotted:
		# check the vdb in case this is multislot
		available_slots = set(vardb.aux_get(cpv, ["SLOT"])[0] \
			for cpv in vardb.match(cp))
		slotted = len(available_slots) > 1 or \
			(len(available_slots) == 1 and "0" not in available_slots)
	if slotted and arg_atom != cp:
		# If the user gave a specific atom, store it as a
		# slot atom in the world file.
		slot_atom = pkg.slot_atom

		# For USE=multislot, there are a couple of cases to
		# handle here:
		#
		# 1) SLOT="0", but the real SLOT spontaneously changed to some
		#    unknown value, so just record an unslotted atom.
		#
		# 2) SLOT comes from an installed package and there is no
		#    matching SLOT in the portage tree.
		#
		# Make sure that the slot atom is available in either the
		# portdb or the vardb, since otherwise the user certainly
		# doesn't want the SLOT atom recorded in the world file
		# (case 1 above).  If it's only available in the vardb,
		# the user may be trying to prevent a USE=multislot
		# package from being removed by --depclean (case 2 above).

		mydb = portdb
		if not portdb.match(slot_atom):
			# SLOT seems to come from an installed multislot package
			mydb = vardb
		# If there is no installed package matching the SLOT atom,
		# it probably changed SLOT spontaneously due to USE=multislot,
		# so just record an unslotted atom.
		if vardb.match(slot_atom):
			# Now verify that the argument is precise
			# enough to identify a specific slot.
			matches = mydb.match(arg_atom)
			matched_slots = set()
			for cpv in matches:
				matched_slots.add(mydb.aux_get(cpv, ["SLOT"])[0])
			if len(matched_slots) == 1:
				new_world_atom = slot_atom

	if new_world_atom == sets["world"].findAtomForPackage(pkg):
		# Both atoms would be identical, so there's nothing to add.
		return None
	if not slotted:
		# Unlike world atoms, system atoms are not greedy for slots, so they
		# can't be safely excluded from world if they are slotted.
		system_atom = sets["system"].findAtomForPackage(pkg)
		if system_atom:
			if not portage.dep_getkey(system_atom).startswith("virtual/"):
				return None
			# System virtuals aren't safe to exclude from world since they can
			# match multiple old-style virtuals but only one of them will be
			# pulled in by update or depclean.
			providers = portdb.mysettings.getvirtuals().get(
				portage.dep_getkey(system_atom))
			if providers and len(providers) == 1 and providers[0] == cp:
				return None
	return new_world_atom

def filter_iuse_defaults(iuse):
	for flag in iuse:
		if flag.startswith("+") or flag.startswith("-"):
			yield flag[1:]
		else:
			yield flag

class SlotObject(object):
	__slots__ = ("__weakref__",)

	def __init__(self, **kwargs):
		classes = [self.__class__]
		while classes:
			c = classes.pop()
			if c is SlotObject:
				continue
			classes.extend(c.__bases__)
			slots = getattr(c, "__slots__", None)
			if not slots:
				continue
			for myattr in slots:
				myvalue = kwargs.get(myattr, None)
				setattr(self, myattr, myvalue)

	def copy(self):
		"""
		Create a new instance and copy all attributes
		defined from __slots__ (including those from
		inherited classes).
		"""
		obj = self.__class__()

		classes = [self.__class__]
		while classes:
			c = classes.pop()
			if c is SlotObject:
				continue
			classes.extend(c.__bases__)
			slots = getattr(c, "__slots__", None)
			if not slots:
				continue
			for myattr in slots:
				setattr(obj, myattr, getattr(self, myattr))

		return obj

class AbstractDepPriority(SlotObject):
	__slots__ = ("buildtime", "runtime", "runtime_post")

	def __lt__(self, other):
		return self.__int__() < other

	def __le__(self, other):
		return self.__int__() <= other

	def __eq__(self, other):
		return self.__int__() == other

	def __ne__(self, other):
		return self.__int__() != other

	def __gt__(self, other):
		return self.__int__() > other

	def __ge__(self, other):
		return self.__int__() >= other

	def copy(self):
		import copy
		return copy.copy(self)

class DepPriority(AbstractDepPriority):

	__slots__ = ("satisfied", "optional", "rebuild")

	def __int__(self):
		return 0

	def __str__(self):
		if self.optional:
			return "optional"
		if self.buildtime:
			return "buildtime"
		if self.runtime:
			return "runtime"
		if self.runtime_post:
			return "runtime_post"
		return "soft"

class BlockerDepPriority(DepPriority):
	__slots__ = ()
	def __int__(self):
		return 0

	def __str__(self):
		return 'blocker'

BlockerDepPriority.instance = BlockerDepPriority()

class UnmergeDepPriority(AbstractDepPriority):
	__slots__ = ("optional", "satisfied",)
	"""
	Combination of properties           Priority  Category

	runtime                                0       HARD
	runtime_post                          -1       HARD
	buildtime                             -2       SOFT
	(none of the above)                   -2       SOFT
	"""

	MAX    =  0
	SOFT   = -2
	MIN    = -2

	def __int__(self):
		if self.runtime:
			return 0
		if self.runtime_post:
			return -1
		if self.buildtime:
			return -2
		return -2

	def __str__(self):
		myvalue = self.__int__()
		if myvalue > self.SOFT:
			return "hard"
		return "soft"

class DepPriorityNormalRange(object):
	"""
	DepPriority properties              Index      Category

	buildtime                                      HARD
	runtime                                3       MEDIUM
	runtime_post                           2       MEDIUM_SOFT
	optional                               1       SOFT
	(none of the above)                    0       NONE
	"""
	MEDIUM      = 3
	MEDIUM_SOFT = 2
	SOFT        = 1
	NONE        = 0

	@classmethod
	def _ignore_optional(cls, priority):
		if priority.__class__ is not DepPriority:
			return False
		return bool(priority.optional)

	@classmethod
	def _ignore_runtime_post(cls, priority):
		if priority.__class__ is not DepPriority:
			return False
		return bool(priority.optional or priority.runtime_post)

	@classmethod
	def _ignore_runtime(cls, priority):
		if priority.__class__ is not DepPriority:
			return False
		return not priority.buildtime

	ignore_medium      = _ignore_runtime
	ignore_medium_soft = _ignore_runtime_post
	ignore_soft        = _ignore_optional

DepPriorityNormalRange.ignore_priority = (
	None,
	DepPriorityNormalRange._ignore_optional,
	DepPriorityNormalRange._ignore_runtime_post,
	DepPriorityNormalRange._ignore_runtime
)

class DepPrioritySatisfiedRange(object):
	"""
	DepPriority                         Index      Category

	not satisfied and buildtime                    HARD
	not satisfied and runtime              7       MEDIUM
	not satisfied and runtime_post         6       MEDIUM_SOFT
	satisfied and buildtime and rebuild    5       SOFT
	satisfied and buildtime                4       SOFT
	satisfied and runtime                  3       SOFT
	satisfied and runtime_post             2       SOFT
	optional                               1       SOFT
	(none of the above)                    0       NONE
	"""
	MEDIUM      = 7
	MEDIUM_SOFT = 6
	SOFT        = 5
	NONE        = 0

	@classmethod
	def _ignore_optional(cls, priority):
		if priority.__class__ is not DepPriority:
			return False
		return bool(priority.optional)

	@classmethod
	def _ignore_satisfied_runtime_post(cls, priority):
		if priority.__class__ is not DepPriority:
			return False
		if priority.optional:
			return True
		if not priority.satisfied:
			return False
		return bool(priority.runtime_post)

	@classmethod
	def _ignore_satisfied_runtime(cls, priority):
		if priority.__class__ is not DepPriority:
			return False
		if priority.optional:
			return True
		if not priority.satisfied:
			return False
		return not priority.buildtime

	@classmethod
	def _ignore_satisfied_buildtime(cls, priority):
		if priority.__class__ is not DepPriority:
			return False
		if priority.optional:
			return True
		if not priority.satisfied:
			return False
		if priority.buildtime:
			return not priority.rebuild
		return True

	@classmethod
	def _ignore_satisfied_buildtime_rebuild(cls, priority):
		if priority.__class__ is not DepPriority:
			return False
		if priority.optional:
			return True
		return bool(priority.satisfied)

	@classmethod
	def _ignore_runtime_post(cls, priority):
		if priority.__class__ is not DepPriority:
			return False
		return bool(priority.optional or \
			priority.satisfied or \
			priority.runtime_post)

	@classmethod
	def _ignore_runtime(cls, priority):
		if priority.__class__ is not DepPriority:
			return False
		return bool(priority.satisfied or \
			not priority.buildtime)

	ignore_medium      = _ignore_runtime
	ignore_medium_soft = _ignore_runtime_post
	ignore_soft        = _ignore_satisfied_buildtime_rebuild

DepPrioritySatisfiedRange.ignore_priority = (
	None,
	DepPrioritySatisfiedRange._ignore_optional,
	DepPrioritySatisfiedRange._ignore_satisfied_runtime_post,
	DepPrioritySatisfiedRange._ignore_satisfied_runtime,
	DepPrioritySatisfiedRange._ignore_satisfied_buildtime,
	DepPrioritySatisfiedRange._ignore_satisfied_buildtime_rebuild,
	DepPrioritySatisfiedRange._ignore_runtime_post,
	DepPrioritySatisfiedRange._ignore_runtime
)

def _find_deep_system_runtime_deps(graph):
	deep_system_deps = set()
	node_stack = []
	for node in graph:
		if not isinstance(node, Package) or \
			node.operation == 'uninstall':
			continue
		if node.root_config.sets['system'].findAtomForPackage(node):
			node_stack.append(node)

	def ignore_priority(priority):
		"""
		Ignore non-runtime priorities.
		"""
		if isinstance(priority, DepPriority) and \
			(priority.runtime or priority.runtime_post):
			return False
		return True

	while node_stack:
		node = node_stack.pop()
		if node in deep_system_deps:
			continue
		deep_system_deps.add(node)
		for child in graph.child_nodes(node, ignore_priority=ignore_priority):
			if not isinstance(child, Package) or \
				child.operation == 'uninstall':
				continue
			node_stack.append(child)

	return deep_system_deps

class FakeVartree(portage.vartree):
	"""This is implements an in-memory copy of a vartree instance that provides
	all the interfaces required for use by the depgraph.  The vardb is locked
	during the constructor call just long enough to read a copy of the
	installed package information.  This allows the depgraph to do it's
	dependency calculations without holding a lock on the vardb.  It also
	allows things like vardb global updates to be done in memory so that the
	user doesn't necessarily need write access to the vardb in cases where
	global updates are necessary (updates are performed when necessary if there
	is not a matching ebuild in the tree)."""
	def __init__(self, root_config, pkg_cache=None, acquire_lock=1):
		self._root_config = root_config
		if pkg_cache is None:
			pkg_cache = {}
		real_vartree = root_config.trees["vartree"]
		portdb = root_config.trees["porttree"].dbapi
		self.root = real_vartree.root
		self.settings = real_vartree.settings
		mykeys = list(real_vartree.dbapi._aux_cache_keys)
		if "_mtime_" not in mykeys:
			mykeys.append("_mtime_")
		self._db_keys = mykeys
		self._pkg_cache = pkg_cache
		self.dbapi = PackageVirtualDbapi(real_vartree.settings)
		vdb_path = os.path.join(self.root, portage.VDB_PATH)
		try:
			# At least the parent needs to exist for the lock file.
			portage.util.ensure_dirs(vdb_path)
		except portage.exception.PortageException:
			pass
		vdb_lock = None
		try:
			if acquire_lock and os.access(vdb_path, os.W_OK):
				vdb_lock = portage.locks.lockdir(vdb_path)
			real_dbapi = real_vartree.dbapi
			slot_counters = {}
			for cpv in real_dbapi.cpv_all():
				cache_key = ("installed", self.root, cpv, "nomerge")
				pkg = self._pkg_cache.get(cache_key)
				if pkg is not None:
					metadata = pkg.metadata
				else:
					metadata = dict(izip(mykeys, real_dbapi.aux_get(cpv, mykeys)))
				myslot = metadata["SLOT"]
				mycp = portage.dep_getkey(cpv)
				myslot_atom = "%s:%s" % (mycp, myslot)
				try:
					mycounter = long(metadata["COUNTER"])
				except ValueError:
					mycounter = 0
					metadata["COUNTER"] = str(mycounter)
				other_counter = slot_counters.get(myslot_atom, None)
				if other_counter is not None:
					if other_counter > mycounter:
						continue
				slot_counters[myslot_atom] = mycounter
				if pkg is None:
					pkg = Package(built=True, cpv=cpv,
						installed=True, metadata=metadata,
						root_config=root_config, type_name="installed")
				self._pkg_cache[pkg] = pkg
				self.dbapi.cpv_inject(pkg)
			real_dbapi.flush_cache()
		finally:
			if vdb_lock:
				portage.locks.unlockdir(vdb_lock)
		# Populate the old-style virtuals using the cached values.
		if not self.settings.treeVirtuals:
			self.settings.treeVirtuals = portage.util.map_dictlist_vals(
				portage.getCPFromCPV, self.get_all_provides())

		# Intialize variables needed for lazy cache pulls of the live ebuild
		# metadata.  This ensures that the vardb lock is released ASAP, without
		# being delayed in case cache generation is triggered.
		self._aux_get = self.dbapi.aux_get
		self.dbapi.aux_get = self._aux_get_wrapper
		self._match = self.dbapi.match
		self.dbapi.match = self._match_wrapper
		self._aux_get_history = set()
		self._portdb_keys = ["EAPI", "DEPEND", "RDEPEND", "PDEPEND"]
		self._portdb = portdb
		self._global_updates = None

	def _match_wrapper(self, cpv, use_cache=1):
		"""
		Make sure the metadata in Package instances gets updated for any
		cpv that is returned from a match() call, since the metadata can
		be accessed directly from the Package instance instead of via
		aux_get().
		"""
		matches = self._match(cpv, use_cache=use_cache)
		for cpv in matches:
			if cpv in self._aux_get_history:
				continue
			self._aux_get_wrapper(cpv, [])
		return matches

	def _aux_get_wrapper(self, pkg, wants):
		if pkg in self._aux_get_history:
			return self._aux_get(pkg, wants)
		self._aux_get_history.add(pkg)
		try:
			# Use the live ebuild metadata if possible.
			live_metadata = dict(izip(self._portdb_keys,
				self._portdb.aux_get(pkg, self._portdb_keys)))
			if not portage.eapi_is_supported(live_metadata["EAPI"]):
				raise KeyError(pkg)
			self.dbapi.aux_update(pkg, live_metadata)
		except (KeyError, portage.exception.PortageException):
			if self._global_updates is None:
				self._global_updates = \
					grab_global_updates(self._portdb.porttree_root)
			perform_global_updates(
				pkg, self.dbapi, self._global_updates)
		return self._aux_get(pkg, wants)

	def sync(self, acquire_lock=1):
		"""
		Call this method to synchronize state with the real vardb
		after one or more packages may have been installed or
		uninstalled.
		"""
		vdb_path = os.path.join(self.root, portage.VDB_PATH)
		try:
			# At least the parent needs to exist for the lock file.
			portage.util.ensure_dirs(vdb_path)
		except portage.exception.PortageException:
			pass
		vdb_lock = None
		try:
			if acquire_lock and os.access(vdb_path, os.W_OK):
				vdb_lock = portage.locks.lockdir(vdb_path)
			self._sync()
		finally:
			if vdb_lock:
				portage.locks.unlockdir(vdb_lock)

	def _sync(self):

		real_vardb = self._root_config.trees["vartree"].dbapi
		current_cpv_set = frozenset(real_vardb.cpv_all())
		pkg_vardb = self.dbapi
		aux_get_history = self._aux_get_history

		# Remove any packages that have been uninstalled.
		for pkg in list(pkg_vardb):
			if pkg.cpv not in current_cpv_set:
				pkg_vardb.cpv_remove(pkg)
				aux_get_history.discard(pkg.cpv)

		# Validate counters and timestamps.
		slot_counters = {}
		root = self.root
		validation_keys = ["COUNTER", "_mtime_"]
		for cpv in current_cpv_set:

			pkg_hash_key = ("installed", root, cpv, "nomerge")
			pkg = pkg_vardb.get(pkg_hash_key)
			if pkg is not None:
				counter, mtime = real_vardb.aux_get(cpv, validation_keys)
				try:
					counter = long(counter)
				except ValueError:
					counter = 0

				if counter != pkg.counter or \
					mtime != pkg.mtime:
					pkg_vardb.cpv_remove(pkg)
					aux_get_history.discard(pkg.cpv)
					pkg = None

			if pkg is None:
				pkg = self._pkg(cpv)

			other_counter = slot_counters.get(pkg.slot_atom)
			if other_counter is not None:
				if other_counter > pkg.counter:
					continue

			slot_counters[pkg.slot_atom] = pkg.counter
			pkg_vardb.cpv_inject(pkg)

		real_vardb.flush_cache()

	def _pkg(self, cpv):
		root_config = self._root_config
		real_vardb = root_config.trees["vartree"].dbapi
		pkg = Package(cpv=cpv, installed=True,
			metadata=izip(self._db_keys,
			real_vardb.aux_get(cpv, self._db_keys)),
			root_config=root_config,
			type_name="installed")

		try:
			mycounter = long(pkg.metadata["COUNTER"])
		except ValueError:
			mycounter = 0
			pkg.metadata["COUNTER"] = str(mycounter)

		return pkg

def grab_global_updates(portdir):
	from portage.update import grab_updates, parse_updates
	updpath = os.path.join(portdir, "profiles", "updates")
	try:
		rawupdates = grab_updates(updpath)
	except portage.exception.DirectoryNotFound:
		rawupdates = []
	upd_commands = []
	for mykey, mystat, mycontent in rawupdates:
		commands, errors = parse_updates(mycontent)
		upd_commands.extend(commands)
	return upd_commands

def perform_global_updates(mycpv, mydb, mycommands):
	from portage.update import update_dbentries
	aux_keys = ["DEPEND", "RDEPEND", "PDEPEND"]
	aux_dict = dict(izip(aux_keys, mydb.aux_get(mycpv, aux_keys)))
	updates = update_dbentries(mycommands, aux_dict)
	if updates:
		mydb.aux_update(mycpv, updates)

def visible(pkgsettings, pkg):
	"""
	Check if a package is visible. This can raise an InvalidDependString
	exception if LICENSE is invalid.
	TODO: optionally generate a list of masking reasons
	@rtype: Boolean
	@returns: True if the package is visible, False otherwise.
	"""
	if not pkg.metadata["SLOT"]:
		return False
	if not pkg.installed:
		if not pkgsettings._accept_chost(pkg.cpv, pkg.metadata):
			return False
	eapi = pkg.metadata["EAPI"]
	if not portage.eapi_is_supported(eapi):
		return False
	if not pkg.installed:
		if portage._eapi_is_deprecated(eapi):
			return False
		if pkgsettings._getMissingKeywords(pkg.cpv, pkg.metadata):
			return False
	if pkgsettings._getMaskAtom(pkg.cpv, pkg.metadata):
		return False
	if pkgsettings._getProfileMaskAtom(pkg.cpv, pkg.metadata):
		return False
	try:
		if pkgsettings._getMissingLicenses(pkg.cpv, pkg.metadata):
			return False
	except portage.exception.InvalidDependString:
		return False
	return True

def get_masking_status(pkg, pkgsettings, root_config):

	mreasons = portage.getmaskingstatus(
		pkg, settings=pkgsettings,
		portdb=root_config.trees["porttree"].dbapi)

	if not pkg.installed:
		if not pkgsettings._accept_chost(pkg.cpv, pkg.metadata):
			mreasons.append("CHOST: %s" % \
				pkg.metadata["CHOST"])

	if not pkg.metadata["SLOT"]:
		mreasons.append("invalid: SLOT is undefined")

	return mreasons

def get_mask_info(root_config, cpv, pkgsettings,
	db, pkg_type, built, installed, db_keys):
	eapi_masked = False
	try:
		metadata = dict(izip(db_keys,
			db.aux_get(cpv, db_keys)))
	except KeyError:
		metadata = None
	if metadata and not built:
		pkgsettings.setcpv(cpv, mydb=metadata)
		metadata["USE"] = pkgsettings["PORTAGE_USE"]
		metadata['CHOST'] = pkgsettings.get('CHOST', '')
	if metadata is None:
		mreasons = ["corruption"]
	else:
		pkg = Package(type_name=pkg_type, root_config=root_config,
			cpv=cpv, built=built, installed=installed, metadata=metadata)
		mreasons = get_masking_status(pkg, pkgsettings, root_config)
	return metadata, mreasons

def show_masked_packages(masked_packages):
	shown_licenses = set()
	shown_comments = set()
	# Maybe there is both an ebuild and a binary. Only
	# show one of them to avoid redundant appearance.
	shown_cpvs = set()
	have_eapi_mask = False
	for (root_config, pkgsettings, cpv,
		metadata, mreasons) in masked_packages:
		if cpv in shown_cpvs:
			continue
		shown_cpvs.add(cpv)
		comment, filename = None, None
		if "package.mask" in mreasons:
			comment, filename = \
				portage.getmaskingreason(
				cpv, metadata=metadata,
				settings=pkgsettings,
				portdb=root_config.trees["porttree"].dbapi,
				return_location=True)
		missing_licenses = []
		if metadata:
			if not portage.eapi_is_supported(metadata["EAPI"]):
				have_eapi_mask = True
			try:
				missing_licenses = \
					pkgsettings._getMissingLicenses(
						cpv, metadata)
			except portage.exception.InvalidDependString:
				# This will have already been reported
				# above via mreasons.
				pass

		print "- "+cpv+" (masked by: "+", ".join(mreasons)+")"
		if comment and comment not in shown_comments:
			print filename+":"
			print comment
			shown_comments.add(comment)
		portdb = root_config.trees["porttree"].dbapi
		for l in missing_licenses:
			l_path = portdb.findLicensePath(l)
			if l in shown_licenses:
				continue
			msg = ("A copy of the '%s' license" + \
			" is located at '%s'.") % (l, l_path)
			print msg
			print
			shown_licenses.add(l)
	return have_eapi_mask

class Task(SlotObject):
	__slots__ = ("_hash_key", "_hash_value")

	def _get_hash_key(self):
		hash_key = getattr(self, "_hash_key", None)
		if hash_key is None:
			raise NotImplementedError(self)
		return hash_key

	def __eq__(self, other):
		return self._get_hash_key() == other

	def __ne__(self, other):
		return self._get_hash_key() != other

	def __hash__(self):
		hash_value = getattr(self, "_hash_value", None)
		if hash_value is None:
			self._hash_value = hash(self._get_hash_key())
		return self._hash_value

	def __len__(self):
		return len(self._get_hash_key())

	def __getitem__(self, key):
		return self._get_hash_key()[key]

	def __iter__(self):
		return iter(self._get_hash_key())

	def __contains__(self, key):
		return key in self._get_hash_key()

	def __str__(self):
		return str(self._get_hash_key())

class Blocker(Task):

	__hash__ = Task.__hash__
	__slots__ = ("root", "atom", "cp", "eapi", "satisfied")

	def __init__(self, **kwargs):
		Task.__init__(self, **kwargs)
		self.cp = portage.dep_getkey(self.atom)

	def _get_hash_key(self):
		hash_key = getattr(self, "_hash_key", None)
		if hash_key is None:
			self._hash_key = \
				("blocks", self.root, self.atom, self.eapi)
		return self._hash_key

class Package(Task):

	__hash__ = Task.__hash__
	__slots__ = ("built", "cpv", "depth",
		"installed", "metadata", "onlydeps", "operation",
		"root_config", "type_name",
		"category", "counter", "cp", "cpv_split",
		"inherited", "iuse", "mtime",
		"pf", "pv_split", "root", "slot", "slot_atom", "use")

	metadata_keys = [
		"CHOST", "COUNTER", "DEPEND", "EAPI",
		"INHERITED", "IUSE", "KEYWORDS",
		"LICENSE", "PDEPEND", "PROVIDE", "RDEPEND",
		"repository", "PROPERTIES", "RESTRICT", "SLOT", "USE", "_mtime_"]

	def __init__(self, **kwargs):
		Task.__init__(self, **kwargs)
		self.root = self.root_config.root
		self.metadata = _PackageMetadataWrapper(self, self.metadata)
		self.cp = portage.cpv_getkey(self.cpv)
		slot = self.slot
		if not slot:
			# Avoid an InvalidAtom exception when creating slot_atom.
			# This package instance will be masked due to empty SLOT.
			slot = '0'
		self.slot_atom = portage.dep.Atom("%s:%s" % (self.cp, slot))
		self.category, self.pf = portage.catsplit(self.cpv)
		self.cpv_split = portage.catpkgsplit(self.cpv)
		self.pv_split = self.cpv_split[1:]

	class _use(object):

		__slots__ = ("__weakref__", "enabled")

		def __init__(self, use):
			self.enabled = frozenset(use)

	class _iuse(object):

		__slots__ = ("__weakref__", "all", "enabled", "disabled", "iuse_implicit", "regex", "tokens")

		def __init__(self, tokens, iuse_implicit):
			self.tokens = tuple(tokens)
			self.iuse_implicit = iuse_implicit
			enabled = []
			disabled = []
			other = []
			for x in tokens:
				prefix = x[:1]
				if prefix == "+":
					enabled.append(x[1:])
				elif prefix == "-":
					disabled.append(x[1:])
				else:
					other.append(x)
			self.enabled = frozenset(enabled)
			self.disabled = frozenset(disabled)
			self.all = frozenset(chain(enabled, disabled, other))

		def __getattribute__(self, name):
			if name == "regex":
				try:
					return object.__getattribute__(self, "regex")
				except AttributeError:
					all = object.__getattribute__(self, "all")
					iuse_implicit = object.__getattribute__(self, "iuse_implicit")
					# Escape anything except ".*" which is supposed
					# to pass through from _get_implicit_iuse()
					regex = (re.escape(x) for x in chain(all, iuse_implicit))
					regex = "^(%s)$" % "|".join(regex)
					regex = regex.replace("\\.\\*", ".*")
					self.regex = re.compile(regex)
			return object.__getattribute__(self, name)

	def _get_hash_key(self):
		hash_key = getattr(self, "_hash_key", None)
		if hash_key is None:
			if self.operation is None:
				self.operation = "merge"
				if self.onlydeps or self.installed:
					self.operation = "nomerge"
			self._hash_key = \
				(self.type_name, self.root, self.cpv, self.operation)
		return self._hash_key

	def __lt__(self, other):
		if other.cp != self.cp:
			return False
		if portage.pkgcmp(self.pv_split, other.pv_split) < 0:
			return True
		return False

	def __le__(self, other):
		if other.cp != self.cp:
			return False
		if portage.pkgcmp(self.pv_split, other.pv_split) <= 0:
			return True
		return False

	def __gt__(self, other):
		if other.cp != self.cp:
			return False
		if portage.pkgcmp(self.pv_split, other.pv_split) > 0:
			return True
		return False

	def __ge__(self, other):
		if other.cp != self.cp:
			return False
		if portage.pkgcmp(self.pv_split, other.pv_split) >= 0:
			return True
		return False

_all_metadata_keys = set(x for x in portage.auxdbkeys \
	if not x.startswith("UNUSED_"))
_all_metadata_keys.discard("CDEPEND")
_all_metadata_keys.update(Package.metadata_keys)

from portage.cache.mappings import slot_dict_class
_PackageMetadataWrapperBase = slot_dict_class(_all_metadata_keys)

class _PackageMetadataWrapper(_PackageMetadataWrapperBase):
	"""
	Detect metadata updates and synchronize Package attributes.
	"""

	__slots__ = ("_pkg",)
	_wrapped_keys = frozenset(
		["COUNTER", "INHERITED", "IUSE", "SLOT", "USE", "_mtime_"])

	def __init__(self, pkg, metadata):
		_PackageMetadataWrapperBase.__init__(self)
		self._pkg = pkg
		self.update(metadata)

	def __setitem__(self, k, v):
		_PackageMetadataWrapperBase.__setitem__(self, k, v)
		if k in self._wrapped_keys:
			getattr(self, "_set_" + k.lower())(k, v)

	def _set_inherited(self, k, v):
		if isinstance(v, basestring):
			v = frozenset(v.split())
		self._pkg.inherited = v

	def _set_iuse(self, k, v):
		self._pkg.iuse = self._pkg._iuse(
			v.split(), self._pkg.root_config.iuse_implicit)

	def _set_slot(self, k, v):
		self._pkg.slot = v

	def _set_use(self, k, v):
		self._pkg.use = self._pkg._use(v.split())

	def _set_counter(self, k, v):
		if isinstance(v, basestring):
			try:
				v = long(v.strip())
			except ValueError:
				v = 0
		self._pkg.counter = v

	def _set__mtime_(self, k, v):
		if isinstance(v, basestring):
			try:
				v = long(v.strip())
			except ValueError:
				v = 0
		self._pkg.mtime = v

class EbuildFetchonly(SlotObject):

	__slots__ = ("fetch_all", "pkg", "pretend", "settings")

	def execute(self):
		settings = self.settings
		pkg = self.pkg
		portdb = pkg.root_config.trees["porttree"].dbapi
		ebuild_path = portdb.findname(pkg.cpv)
		settings.setcpv(pkg)
		debug = settings.get("PORTAGE_DEBUG") == "1"
		use_cache = 1 # always true
		portage.doebuild_environment(ebuild_path, "fetch",
			settings["ROOT"], settings, debug, use_cache, portdb)
		restrict_fetch = 'fetch' in settings['PORTAGE_RESTRICT'].split()

		if restrict_fetch:
			rval = self._execute_with_builddir()
		else:
			rval = portage.doebuild(ebuild_path, "fetch",
				settings["ROOT"], settings, debug=debug,
				listonly=self.pretend, fetchonly=1, fetchall=self.fetch_all,
				mydbapi=portdb, tree="porttree")

			if rval != os.EX_OK:
				msg = "Fetch failed for '%s'" % (pkg.cpv,)
				eerror(msg, phase="unpack", key=pkg.cpv)

		return rval

	def _execute_with_builddir(self):
		# To spawn pkg_nofetch requires PORTAGE_BUILDDIR for
		# ensuring sane $PWD (bug #239560) and storing elog
		# messages. Use a private temp directory, in order
		# to avoid locking the main one.
		settings = self.settings
		global_tmpdir = settings["PORTAGE_TMPDIR"]
		from tempfile import mkdtemp
		try:
			private_tmpdir = mkdtemp("", "._portage_fetch_.", global_tmpdir)
		except OSError, e:
			if e.errno != portage.exception.PermissionDenied.errno:
				raise
			raise portage.exception.PermissionDenied(global_tmpdir)
		settings["PORTAGE_TMPDIR"] = private_tmpdir
		settings.backup_changes("PORTAGE_TMPDIR")
		try:
			retval = self._execute()
		finally:
			settings["PORTAGE_TMPDIR"] = global_tmpdir
			settings.backup_changes("PORTAGE_TMPDIR")
			shutil.rmtree(private_tmpdir)
		return retval

	def _execute(self):
		settings = self.settings
		pkg = self.pkg
		root_config = pkg.root_config
		portdb = root_config.trees["porttree"].dbapi
		ebuild_path = portdb.findname(pkg.cpv)
		debug = settings.get("PORTAGE_DEBUG") == "1"
		portage.prepare_build_dirs(self.pkg.root, self.settings, 0)

		retval = portage.doebuild(ebuild_path, "fetch",
			self.settings["ROOT"], self.settings, debug=debug,
			listonly=self.pretend, fetchonly=1, fetchall=self.fetch_all,
			mydbapi=portdb, tree="porttree")

		if retval != os.EX_OK:
			msg = "Fetch failed for '%s'" % (pkg.cpv,)
			eerror(msg, phase="unpack", key=pkg.cpv)

		portage.elog.elog_process(self.pkg.cpv, self.settings)
		return retval

class PollConstants(object):

	"""
	Provides POLL* constants that are equivalent to those from the
	select module, for use by PollSelectAdapter.
	"""

	names = ("POLLIN", "POLLPRI", "POLLOUT", "POLLERR", "POLLHUP", "POLLNVAL")
	v = 1
	for k in names:
		locals()[k] = getattr(select, k, v)
		v *= 2
	del k, v

class AsynchronousTask(SlotObject):
	"""
	Subclasses override _wait() and _poll() so that calls
	to public methods can be wrapped for implementing
	hooks such as exit listener notification.

	Sublasses should call self.wait() to notify exit listeners after
	the task is complete and self.returncode has been set.
	"""

	__slots__ = ("background", "cancelled", "returncode") + \
		("_exit_listeners", "_exit_listener_stack", "_start_listeners")

	def start(self):
		"""
		Start an asynchronous task and then return as soon as possible.
		"""
		self._start_hook()
		self._start()

	def _start(self):
		raise NotImplementedError(self)

	def isAlive(self):
		return self.returncode is None

	def poll(self):
		self._wait_hook()
		return self._poll()

	def _poll(self):
		return self.returncode

	def wait(self):
		if self.returncode is None:
			self._wait()
		self._wait_hook()
		return self.returncode

	def _wait(self):
		return self.returncode

	def cancel(self):
		self.cancelled = True
		self.wait()

	def addStartListener(self, f):
		"""
		The function will be called with one argument, a reference to self.
		"""
		if self._start_listeners is None:
			self._start_listeners = []
		self._start_listeners.append(f)

	def removeStartListener(self, f):
		if self._start_listeners is None:
			return
		self._start_listeners.remove(f)

	def _start_hook(self):
		if self._start_listeners is not None:
			start_listeners = self._start_listeners
			self._start_listeners = None

			for f in start_listeners:
				f(self)

	def addExitListener(self, f):
		"""
		The function will be called with one argument, a reference to self.
		"""
		if self._exit_listeners is None:
			self._exit_listeners = []
		self._exit_listeners.append(f)

	def removeExitListener(self, f):
		if self._exit_listeners is None:
			if self._exit_listener_stack is not None:
				self._exit_listener_stack.remove(f)
			return
		self._exit_listeners.remove(f)

	def _wait_hook(self):
		"""
		Call this method after the task completes, just before returning
		the returncode from wait() or poll(). This hook is
		used to trigger exit listeners when the returncode first
		becomes available.
		"""
		if self.returncode is not None and \
			self._exit_listeners is not None:

			# This prevents recursion, in case one of the
			# exit handlers triggers this method again by
			# calling wait(). Use a stack that gives
			# removeExitListener() an opportunity to consume
			# listeners from the stack, before they can get
			# called below. This is necessary because a call
			# to one exit listener may result in a call to
			# removeExitListener() for another listener on
			# the stack. That listener needs to be removed
			# from the stack since it would be inconsistent
			# to call it after it has been been passed into
			# removeExitListener().
			self._exit_listener_stack = self._exit_listeners
			self._exit_listeners = None

			self._exit_listener_stack.reverse()
			while self._exit_listener_stack:
				self._exit_listener_stack.pop()(self)

class AbstractPollTask(AsynchronousTask):

	__slots__ = ("scheduler",) + \
		("_registered",)

	_bufsize = 4096
	_exceptional_events = PollConstants.POLLERR | PollConstants.POLLNVAL
	_registered_events = PollConstants.POLLIN | PollConstants.POLLHUP | \
		_exceptional_events

	def _unregister(self):
		raise NotImplementedError(self)

	def _unregister_if_appropriate(self, event):
		if self._registered:
			if event & self._exceptional_events:
				self._unregister()
				self.cancel()
			elif event & PollConstants.POLLHUP:
				self._unregister()
				self.wait()

class PipeReader(AbstractPollTask):

	"""
	Reads output from one or more files and saves it in memory,
	for retrieval via the getvalue() method. This is driven by
	the scheduler's poll() loop, so it runs entirely within the
	current process.
	"""

	__slots__ = ("input_files",) + \
		("_read_data", "_reg_ids")

	def _start(self):
		self._reg_ids = set()
		self._read_data = []
		for k, f in self.input_files.iteritems():
			fcntl.fcntl(f.fileno(), fcntl.F_SETFL,
				fcntl.fcntl(f.fileno(), fcntl.F_GETFL) | os.O_NONBLOCK)
			self._reg_ids.add(self.scheduler.register(f.fileno(),
				self._registered_events, self._output_handler))
		self._registered = True

	def isAlive(self):
		return self._registered

	def cancel(self):
		if self.returncode is None:
			self.returncode = 1
			self.cancelled = True
		self.wait()

	def _wait(self):
		if self.returncode is not None:
			return self.returncode

		if self._registered:
			self.scheduler.schedule(self._reg_ids)
			self._unregister()

		self.returncode = os.EX_OK
		return self.returncode

	def getvalue(self):
		"""Retrieve the entire contents"""
		if sys.hexversion >= 0x3000000:
			return bytes().join(self._read_data)
		return "".join(self._read_data)

	def close(self):
		"""Free the memory buffer."""
		self._read_data = None

	def _output_handler(self, fd, event):

		if event & PollConstants.POLLIN:

			for f in self.input_files.itervalues():
				if fd == f.fileno():
					break

			buf = array.array('B')
			try:
				buf.fromfile(f, self._bufsize)
			except EOFError:
				pass

			if buf:
				self._read_data.append(buf.tostring())
			else:
				self._unregister()
				self.wait()

		self._unregister_if_appropriate(event)
		return self._registered

	def _unregister(self):
		"""
		Unregister from the scheduler and close open files.
		"""

		self._registered = False

		if self._reg_ids is not None:
			for reg_id in self._reg_ids:
				self.scheduler.unregister(reg_id)
			self._reg_ids = None

		if self.input_files is not None:
			for f in self.input_files.itervalues():
				f.close()
			self.input_files = None

class CompositeTask(AsynchronousTask):

	__slots__ = ("scheduler",) + ("_current_task",)

	def isAlive(self):
		return self._current_task is not None

	def cancel(self):
		self.cancelled = True
		if self._current_task is not None:
			self._current_task.cancel()

	def _poll(self):
		"""
		This does a loop calling self._current_task.poll()
		repeatedly as long as the value of self._current_task
		keeps changing. It calls poll() a maximum of one time
		for a given self._current_task instance. This is useful
		since calling poll() on a task can trigger advance to
		the next task could eventually lead to the returncode
		being set in cases when polling only a single task would
		not have the same effect.
		"""

		prev = None
		while True:
			task = self._current_task
			if task is None or task is prev:
				# don't poll the same task more than once
				break
			task.poll()
			prev = task

		return self.returncode

	def _wait(self):

		prev = None
		while True:
			task = self._current_task
			if task is None:
				# don't wait for the same task more than once
				break
			if task is prev:
				# Before the task.wait() method returned, an exit
				# listener should have set self._current_task to either
				# a different task or None. Something is wrong.
				raise AssertionError("self._current_task has not " + \
					"changed since calling wait", self, task)
			task.wait()
			prev = task

		return self.returncode

	def _assert_current(self, task):
		"""
		Raises an AssertionError if the given task is not the
		same one as self._current_task. This can be useful
		for detecting bugs.
		"""
		if task is not self._current_task:
			raise AssertionError("Unrecognized task: %s" % (task,))

	def _default_exit(self, task):
		"""
		Calls _assert_current() on the given task and then sets the
		composite returncode attribute if task.returncode != os.EX_OK.
		If the task failed then self._current_task will be set to None.
		Subclasses can use this as a generic task exit callback.

		@rtype: int
		@returns: The task.returncode attribute.
		"""
		self._assert_current(task)
		if task.returncode != os.EX_OK:
			self.returncode = task.returncode
			self._current_task = None
		return task.returncode

	def _final_exit(self, task):
		"""
		Assumes that task is the final task of this composite task.
		Calls _default_exit() and sets self.returncode to the task's
		returncode and sets self._current_task to None.
		"""
		self._default_exit(task)
		self._current_task = None
		self.returncode = task.returncode
		return self.returncode

	def _default_final_exit(self, task):
		"""
		This calls _final_exit() and then wait().

		Subclasses can use this as a generic final task exit callback.

		"""
		self._final_exit(task)
		return self.wait()

	def _start_task(self, task, exit_handler):
		"""
		Register exit handler for the given task, set it
		as self._current_task, and call task.start().

		Subclasses can use this as a generic way to start
		a task.

		"""
		task.addExitListener(exit_handler)
		self._current_task = task
		task.start()

class TaskSequence(CompositeTask):
	"""
	A collection of tasks that executes sequentially. Each task
	must have a addExitListener() method that can be used as
	a means to trigger movement from one task to the next.
	"""

	__slots__ = ("_task_queue",)

	def __init__(self, **kwargs):
		AsynchronousTask.__init__(self, **kwargs)
		self._task_queue = deque()

	def add(self, task):
		self._task_queue.append(task)

	def _start(self):
		self._start_next_task()

	def cancel(self):
		self._task_queue.clear()
		CompositeTask.cancel(self)

	def _start_next_task(self):
		self._start_task(self._task_queue.popleft(),
			self._task_exit_handler)

	def _task_exit_handler(self, task):
		if self._default_exit(task) != os.EX_OK:
			self.wait()
		elif self._task_queue:
			self._start_next_task()
		else:
			self._final_exit(task)
			self.wait()

class SubProcess(AbstractPollTask):

	__slots__ = ("pid",) + \
		("_files", "_reg_id")

	# A file descriptor is required for the scheduler to monitor changes from
	# inside a poll() loop. When logging is not enabled, create a pipe just to
	# serve this purpose alone.
	_dummy_pipe_fd = 9

	def _poll(self):
		if self.returncode is not None:
			return self.returncode
		if self.pid is None:
			return self.returncode
		if self._registered:
			return self.returncode

		try:
			retval = os.waitpid(self.pid, os.WNOHANG)
		except OSError, e:
			if e.errno != errno.ECHILD:
				raise
			del e
			retval = (self.pid, 1)

		if retval == (0, 0):
			return None
		self._set_returncode(retval)
		return self.returncode

	def cancel(self):
		if self.isAlive():
			try:
				os.kill(self.pid, signal.SIGTERM)
			except OSError, e:
				if e.errno != errno.ESRCH:
					raise
				del e

		self.cancelled = True
		if self.pid is not None:
			self.wait()
		return self.returncode

	def isAlive(self):
		return self.pid is not None and \
			self.returncode is None

	def _wait(self):

		if self.returncode is not None:
			return self.returncode

		if self._registered:
			self.scheduler.schedule(self._reg_id)
			self._unregister()
			if self.returncode is not None:
				return self.returncode

		try:
			wait_retval = os.waitpid(self.pid, 0)
		except OSError, e:
			if e.errno != errno.ECHILD:
				raise
			del e
			self._set_returncode((self.pid, 1))
		else:
			self._set_returncode(wait_retval)

		return self.returncode

	def _unregister(self):
		"""
		Unregister from the scheduler and close open files.
		"""

		self._registered = False

		if self._reg_id is not None:
			self.scheduler.unregister(self._reg_id)
			self._reg_id = None

		if self._files is not None:
			for f in self._files.itervalues():
				f.close()
			self._files = None

	def _set_returncode(self, wait_retval):

		retval = wait_retval[1]

		if retval != os.EX_OK:
			if retval & 0xff:
				retval = (retval & 0xff) << 8
			else:
				retval = retval >> 8

		self.returncode = retval

class SpawnProcess(SubProcess):

	"""
	Constructor keyword args are passed into portage.process.spawn().
	The required "args" keyword argument will be passed as the first
	spawn() argument.
	"""

	_spawn_kwarg_names = ("env", "opt_name", "fd_pipes",
		"uid", "gid", "groups", "umask", "logfile",
		"path_lookup", "pre_exec")

	__slots__ = ("args",) + \
		_spawn_kwarg_names

	_file_names = ("log", "process", "stdout")
	_files_dict = slot_dict_class(_file_names, prefix="")

	def _start(self):

		if self.cancelled:
			return

		if self.fd_pipes is None:
			self.fd_pipes = {}
		fd_pipes = self.fd_pipes
		fd_pipes.setdefault(0, sys.stdin.fileno())
		fd_pipes.setdefault(1, sys.stdout.fileno())
		fd_pipes.setdefault(2, sys.stderr.fileno())

		# flush any pending output
		for fd in fd_pipes.itervalues():
			if fd == sys.stdout.fileno():
				sys.stdout.flush()
			if fd == sys.stderr.fileno():
				sys.stderr.flush()

		logfile = self.logfile
		self._files = self._files_dict()
		files = self._files

		master_fd, slave_fd = self._pipe(fd_pipes)
		fcntl.fcntl(master_fd, fcntl.F_SETFL,
			fcntl.fcntl(master_fd, fcntl.F_GETFL) | os.O_NONBLOCK)

		null_input = None
		fd_pipes_orig = fd_pipes.copy()
		if self.background:
			# TODO: Use job control functions like tcsetpgrp() to control
			# access to stdin. Until then, use /dev/null so that any
			# attempts to read from stdin will immediately return EOF
			# instead of blocking indefinitely.
			null_input = open('/dev/null', 'rb')
			fd_pipes[0] = null_input.fileno()
		else:
			fd_pipes[0] = fd_pipes_orig[0]

		files.process = os.fdopen(master_fd, 'rb')
		if logfile is not None:

			fd_pipes[1] = slave_fd
			fd_pipes[2] = slave_fd

			files.log = open(logfile, mode='ab')
			portage.util.apply_secpass_permissions(logfile,
				uid=portage.portage_uid, gid=portage.portage_gid,
				mode=0660)

			if not self.background:
				files.stdout = os.fdopen(os.dup(fd_pipes_orig[1]), 'wb')

			output_handler = self._output_handler

		else:

			# Create a dummy pipe so the scheduler can monitor
			# the process from inside a poll() loop.
			fd_pipes[self._dummy_pipe_fd] = slave_fd
			if self.background:
				fd_pipes[1] = slave_fd
				fd_pipes[2] = slave_fd
			output_handler = self._dummy_handler

		kwargs = {}
		for k in self._spawn_kwarg_names:
			v = getattr(self, k)
			if v is not None:
				kwargs[k] = v

		kwargs["fd_pipes"] = fd_pipes
		kwargs["returnpid"] = True
		kwargs.pop("logfile", None)

		self._reg_id = self.scheduler.register(files.process.fileno(),
			self._registered_events, output_handler)
		self._registered = True

		retval = self._spawn(self.args, **kwargs)

		os.close(slave_fd)
		if null_input is not None:
			null_input.close()

		if isinstance(retval, int):
			# spawn failed
			self._unregister()
			self.returncode = retval
			self.wait()
			return

		self.pid = retval[0]
		portage.process.spawned_pids.remove(self.pid)

	def _pipe(self, fd_pipes):
		"""
		@type fd_pipes: dict
		@param fd_pipes: pipes from which to copy terminal size if desired.
		"""
		return os.pipe()

	def _spawn(self, args, **kwargs):
		return portage.process.spawn(args, **kwargs)

	def _output_handler(self, fd, event):

		if event & PollConstants.POLLIN:

			files = self._files
			buf = array.array('B')
			try:
				buf.fromfile(files.process, self._bufsize)
			except EOFError:
				pass

			if buf:
				if not self.background:
					buf.tofile(files.stdout)
					files.stdout.flush()
				buf.tofile(files.log)
				files.log.flush()
			else:
				self._unregister()
				self.wait()

		self._unregister_if_appropriate(event)
		return self._registered

	def _dummy_handler(self, fd, event):
		"""
		This method is mainly interested in detecting EOF, since
		the only purpose of the pipe is to allow the scheduler to
		monitor the process from inside a poll() loop.
		"""

		if event & PollConstants.POLLIN:

			buf = array.array('B')
			try:
				buf.fromfile(self._files.process, self._bufsize)
			except EOFError:
				pass

			if buf:
				pass
			else:
				self._unregister()
				self.wait()

		self._unregister_if_appropriate(event)
		return self._registered

class MiscFunctionsProcess(SpawnProcess):
	"""
	Spawns misc-functions.sh with an existing ebuild environment.
	"""

	__slots__ = ("commands", "phase", "pkg", "settings")

	def _start(self):
		settings = self.settings
		settings.pop("EBUILD_PHASE", None)
		portage_bin_path = settings["PORTAGE_BIN_PATH"]
		misc_sh_binary = os.path.join(portage_bin_path,
			os.path.basename(portage.const.MISC_SH_BINARY))

		self.args = [portage._shell_quote(misc_sh_binary)] + self.commands
		self.logfile = settings.get("PORTAGE_LOG_FILE")

		portage._doebuild_exit_status_unlink(
			settings.get("EBUILD_EXIT_STATUS_FILE"))

		SpawnProcess._start(self)

	def _spawn(self, args, **kwargs):
		settings = self.settings
		debug = settings.get("PORTAGE_DEBUG") == "1"
		return portage.spawn(" ".join(args), settings,
			debug=debug, **kwargs)

	def _set_returncode(self, wait_retval):
		SpawnProcess._set_returncode(self, wait_retval)
		self.returncode = portage._doebuild_exit_status_check_and_log(
			self.settings, self.phase, self.returncode)

class EbuildFetcher(SpawnProcess):

	__slots__ = ("config_pool", "fetchonly", "fetchall", "pkg", "prefetch") + \
		("_build_dir",)

	def _start(self):

		root_config = self.pkg.root_config
		portdb = root_config.trees["porttree"].dbapi
		ebuild_path = portdb.findname(self.pkg.cpv)
		settings = self.config_pool.allocate()
		settings.setcpv(self.pkg)

		# In prefetch mode, logging goes to emerge-fetch.log and the builddir
		# should not be touched since otherwise it could interfere with
		# another instance of the same cpv concurrently being built for a
		# different $ROOT (currently, builds only cooperate with prefetchers
		# that are spawned for the same $ROOT).
		if not self.prefetch:
			self._build_dir = EbuildBuildDir(pkg=self.pkg, settings=settings)
			self._build_dir.lock()
			self._build_dir.clean_log()
			portage.prepare_build_dirs(self.pkg.root, self._build_dir.settings, 0)
			if self.logfile is None:
				self.logfile = settings.get("PORTAGE_LOG_FILE")

		phase = "fetch"
		if self.fetchall:
			phase = "fetchall"

		# If any incremental variables have been overridden
		# via the environment, those values need to be passed
		# along here so that they are correctly considered by
		# the config instance in the subproccess.
		fetch_env = os.environ.copy()

		nocolor = settings.get("NOCOLOR")
		if nocolor is not None:
			fetch_env["NOCOLOR"] = nocolor

		fetch_env["PORTAGE_NICENESS"] = "0"
		if self.prefetch:
			fetch_env["PORTAGE_PARALLEL_FETCHONLY"] = "1"

		ebuild_binary = os.path.join(
			settings["PORTAGE_BIN_PATH"], "ebuild")

		fetch_args = [ebuild_binary, ebuild_path, phase]
		debug = settings.get("PORTAGE_DEBUG") == "1"
		if debug:
			fetch_args.append("--debug")

		self.args = fetch_args
		self.env = fetch_env
		SpawnProcess._start(self)

	def _pipe(self, fd_pipes):
		"""When appropriate, use a pty so that fetcher progress bars,
		like wget has, will work properly."""
		if self.background or not sys.stdout.isatty():
			# When the output only goes to a log file,
			# there's no point in creating a pty.
			return os.pipe()
		stdout_pipe = fd_pipes.get(1)
		got_pty, master_fd, slave_fd = \
			portage._create_pty_or_pipe(copy_term_size=stdout_pipe)
		return (master_fd, slave_fd)

	def _set_returncode(self, wait_retval):
		SpawnProcess._set_returncode(self, wait_retval)
		# Collect elog messages that might have been
		# created by the pkg_nofetch phase.
		if self._build_dir is not None:
			# Skip elog messages for prefetch, in order to avoid duplicates.
			if not self.prefetch and self.returncode != os.EX_OK:
				elog_out = None
				if self.logfile is not None:
					if self.background:
						elog_out = open(self.logfile, 'a')
				msg = "Fetch failed for '%s'" % (self.pkg.cpv,)
				if self.logfile is not None:
					msg += ", Log file:"
				eerror(msg, phase="unpack", key=self.pkg.cpv, out=elog_out)
				if self.logfile is not None:
					eerror(" '%s'" % (self.logfile,),
						phase="unpack", key=self.pkg.cpv, out=elog_out)
				if elog_out is not None:
					elog_out.close()
			if not self.prefetch:
				portage.elog.elog_process(self.pkg.cpv, self._build_dir.settings)
			features = self._build_dir.settings.features
			if self.returncode == os.EX_OK:
				self._build_dir.clean_log()
			self._build_dir.unlock()
			self.config_pool.deallocate(self._build_dir.settings)
			self._build_dir = None

class EbuildBuildDir(SlotObject):

	__slots__ = ("dir_path", "pkg", "settings",
		"locked", "_catdir", "_lock_obj")

	def __init__(self, **kwargs):
		SlotObject.__init__(self, **kwargs)
		self.locked = False

	def lock(self):
		"""
		This raises an AlreadyLocked exception if lock() is called
		while a lock is already held. In order to avoid this, call
		unlock() or check whether the "locked" attribute is True
		or False before calling lock().
		"""
		if self._lock_obj is not None:
			raise self.AlreadyLocked((self._lock_obj,))

		dir_path = self.dir_path
		if dir_path is None:
			root_config = self.pkg.root_config
			portdb = root_config.trees["porttree"].dbapi
			ebuild_path = portdb.findname(self.pkg.cpv)
			settings = self.settings
			settings.setcpv(self.pkg)
			debug = settings.get("PORTAGE_DEBUG") == "1"
			use_cache = 1 # always true
			portage.doebuild_environment(ebuild_path, "setup", root_config.root,
				self.settings, debug, use_cache, portdb)
			dir_path = self.settings["PORTAGE_BUILDDIR"]

		catdir = os.path.dirname(dir_path)
		self._catdir = catdir

		portage.util.ensure_dirs(os.path.dirname(catdir),
			gid=portage.portage_gid,
			mode=070, mask=0)
		catdir_lock = None
		try:
			catdir_lock = portage.locks.lockdir(catdir)
			portage.util.ensure_dirs(catdir,
				gid=portage.portage_gid,
				mode=070, mask=0)
			self._lock_obj = portage.locks.lockdir(dir_path)
		finally:
			self.locked = self._lock_obj is not None
			if catdir_lock is not None:
				portage.locks.unlockdir(catdir_lock)

	def clean_log(self):
		"""Discard existing log."""
		settings = self.settings

		for x in ('.logid', 'temp/build.log'):
			try:
				os.unlink(os.path.join(settings["PORTAGE_BUILDDIR"], x))
			except OSError:
				pass

	def unlock(self):
		if self._lock_obj is None:
			return

		portage.locks.unlockdir(self._lock_obj)
		self._lock_obj = None
		self.locked = False

		catdir = self._catdir
		catdir_lock = None
		try:
			catdir_lock = portage.locks.lockdir(catdir)
		finally:
			if catdir_lock:
				try:
					os.rmdir(catdir)
				except OSError, e:
					if e.errno not in (errno.ENOENT,
						errno.ENOTEMPTY, errno.EEXIST):
						raise
					del e
				portage.locks.unlockdir(catdir_lock)

	class AlreadyLocked(portage.exception.PortageException):
		pass

class EbuildBuild(CompositeTask):

	__slots__ = ("args_set", "config_pool", "find_blockers",
		"ldpath_mtimes", "logger", "opts", "pkg", "pkg_count",
		"prefetcher", "settings", "world_atom") + \
		("_build_dir", "_buildpkg", "_ebuild_path", "_issyspkg", "_tree")

	def _start(self):

		logger = self.logger
		opts = self.opts
		pkg = self.pkg
		settings = self.settings
		world_atom = self.world_atom
		root_config = pkg.root_config
		tree = "porttree"
		self._tree = tree
		portdb = root_config.trees[tree].dbapi
		settings.setcpv(pkg)
		settings.configdict["pkg"]["EMERGE_FROM"] = pkg.type_name
		ebuild_path = portdb.findname(self.pkg.cpv)
		self._ebuild_path = ebuild_path

		prefetcher = self.prefetcher
		if prefetcher is None:
			pass
		elif not prefetcher.isAlive():
			prefetcher.cancel()
		elif prefetcher.poll() is None:

			waiting_msg = "Fetching files " + \
				"in the background. " + \
				"To view fetch progress, run `tail -f " + \
				"/var/log/emerge-fetch.log` in another " + \
				"terminal."
			msg_prefix = colorize("GOOD", " * ")
			from textwrap import wrap
			waiting_msg = "".join("%s%s\n" % (msg_prefix, line) \
				for line in wrap(waiting_msg, 65))
			if not self.background:
				writemsg(waiting_msg, noiselevel=-1)

			self._current_task = prefetcher
			prefetcher.addExitListener(self._prefetch_exit)
			return

		self._prefetch_exit(prefetcher)

	def _prefetch_exit(self, prefetcher):

		opts = self.opts
		pkg = self.pkg
		settings = self.settings

		if opts.fetchonly:
				fetcher = EbuildFetchonly(
					fetch_all=opts.fetch_all_uri,
					pkg=pkg, pretend=opts.pretend,
					settings=settings)
				retval = fetcher.execute()
				self.returncode = retval
				self.wait()
				return

		fetcher = EbuildFetcher(config_pool=self.config_pool,
			fetchall=opts.fetch_all_uri,
			fetchonly=opts.fetchonly,
			background=self.background,
			pkg=pkg, scheduler=self.scheduler)

		self._start_task(fetcher, self._fetch_exit)

	def _fetch_exit(self, fetcher):
		opts = self.opts
		pkg = self.pkg

		fetch_failed = False
		if opts.fetchonly:
			fetch_failed = self._final_exit(fetcher) != os.EX_OK
		else:
			fetch_failed = self._default_exit(fetcher) != os.EX_OK

		if fetch_failed and fetcher.logfile is not None and \
			os.path.exists(fetcher.logfile):
			self.settings["PORTAGE_LOG_FILE"] = fetcher.logfile

		if not fetch_failed and fetcher.logfile is not None:
			# Fetch was successful, so remove the fetch log.
			try:
				os.unlink(fetcher.logfile)
			except OSError:
				pass

		if fetch_failed or opts.fetchonly:
			self.wait()
			return

		logger = self.logger
		opts = self.opts
		pkg_count = self.pkg_count
		scheduler = self.scheduler
		settings = self.settings
		features = settings.features
		ebuild_path = self._ebuild_path
		system_set = pkg.root_config.sets["system"]

		self._build_dir = EbuildBuildDir(pkg=pkg, settings=settings)
		self._build_dir.lock()

		# Cleaning is triggered before the setup
		# phase, in portage.doebuild().
		msg = " === (%s of %s) Cleaning (%s::%s)" % \
			(pkg_count.curval, pkg_count.maxval, pkg.cpv, ebuild_path)
		short_msg = "emerge: (%s of %s) %s Clean" % \
			(pkg_count.curval, pkg_count.maxval, pkg.cpv)
		logger.log(msg, short_msg=short_msg)

		#buildsyspkg: Check if we need to _force_ binary package creation
		self._issyspkg = "buildsyspkg" in features and \
				system_set.findAtomForPackage(pkg) and \
				not opts.buildpkg

		if opts.buildpkg or self._issyspkg:

			self._buildpkg = True

			msg = " === (%s of %s) Compiling/Packaging (%s::%s)" % \
				(pkg_count.curval, pkg_count.maxval, pkg.cpv, ebuild_path)
			short_msg = "emerge: (%s of %s) %s Compile" % \
				(pkg_count.curval, pkg_count.maxval, pkg.cpv)
			logger.log(msg, short_msg=short_msg)

		else:
			msg = " === (%s of %s) Compiling/Merging (%s::%s)" % \
				(pkg_count.curval, pkg_count.maxval, pkg.cpv, ebuild_path)
			short_msg = "emerge: (%s of %s) %s Compile" % \
				(pkg_count.curval, pkg_count.maxval, pkg.cpv)
			logger.log(msg, short_msg=short_msg)

		build = EbuildExecuter(background=self.background, pkg=pkg,
			scheduler=scheduler, settings=settings)
		self._start_task(build, self._build_exit)

	def _unlock_builddir(self):
		portage.elog.elog_process(self.pkg.cpv, self.settings)
		self._build_dir.unlock()

	def _build_exit(self, build):
		if self._default_exit(build) != os.EX_OK:
			self._unlock_builddir()
			self.wait()
			return

		opts = self.opts
		buildpkg = self._buildpkg

		if not buildpkg:
			self._final_exit(build)
			self.wait()
			return

		if self._issyspkg:
			msg = ">>> This is a system package, " + \
				"let's pack a rescue tarball.\n"

			log_path = self.settings.get("PORTAGE_LOG_FILE")
			if log_path is not None:
				log_file = open(log_path, 'a')
				try:
					log_file.write(msg)
				finally:
					log_file.close()

			if not self.background:
				portage.writemsg_stdout(msg, noiselevel=-1)

		packager = EbuildBinpkg(background=self.background, pkg=self.pkg,
			scheduler=self.scheduler, settings=self.settings)

		self._start_task(packager, self._buildpkg_exit)

	def _buildpkg_exit(self, packager):
		"""
		Released build dir lock when there is a failure or
		when in buildpkgonly mode. Otherwise, the lock will
		be released when merge() is called.
		"""

		if self._default_exit(packager) != os.EX_OK:
			self._unlock_builddir()
			self.wait()
			return

		if self.opts.buildpkgonly:
			# Need to call "clean" phase for buildpkgonly mode
			portage.elog.elog_process(self.pkg.cpv, self.settings)
			phase = "clean"
			clean_phase = EbuildPhase(background=self.background,
				pkg=self.pkg, phase=phase,
				scheduler=self.scheduler, settings=self.settings,
				tree=self._tree)
			self._start_task(clean_phase, self._clean_exit)
			return

		# Continue holding the builddir lock until
		# after the package has been installed.
		self._current_task = None
		self.returncode = packager.returncode
		self.wait()

	def _clean_exit(self, clean_phase):
		if self._final_exit(clean_phase) != os.EX_OK or \
			self.opts.buildpkgonly:
			self._unlock_builddir()
		self.wait()

	def install(self):
		"""
		Install the package and then clean up and release locks.
		Only call this after the build has completed successfully
		and neither fetchonly nor buildpkgonly mode are enabled.
		"""

		find_blockers = self.find_blockers
		ldpath_mtimes = self.ldpath_mtimes
		logger = self.logger
		pkg = self.pkg
		pkg_count = self.pkg_count
		settings = self.settings
		world_atom = self.world_atom
		ebuild_path = self._ebuild_path
		tree = self._tree

		merge = EbuildMerge(find_blockers=self.find_blockers,
			ldpath_mtimes=ldpath_mtimes, logger=logger, pkg=pkg,
			pkg_count=pkg_count, pkg_path=ebuild_path,
			scheduler=self.scheduler,
			settings=settings, tree=tree, world_atom=world_atom)

		msg = " === (%s of %s) Merging (%s::%s)" % \
			(pkg_count.curval, pkg_count.maxval,
			pkg.cpv, ebuild_path)
		short_msg = "emerge: (%s of %s) %s Merge" % \
			(pkg_count.curval, pkg_count.maxval, pkg.cpv)
		logger.log(msg, short_msg=short_msg)

		try:
			rval = merge.execute()
		finally:
			self._unlock_builddir()

		return rval

class EbuildExecuter(CompositeTask):

	__slots__ = ("pkg", "scheduler", "settings") + ("_tree",)

	_phases = ("prepare", "configure", "compile", "test", "install")

	_live_eclasses = frozenset([
		"bzr",
		"cvs",
		"darcs",
		"git",
		"mercurial",
		"subversion"
	])

	def _start(self):
		self._tree = "porttree"
		pkg = self.pkg
		phase = "clean"
		clean_phase = EbuildPhase(background=self.background, pkg=pkg, phase=phase,
			scheduler=self.scheduler, settings=self.settings, tree=self._tree)
		self._start_task(clean_phase, self._clean_phase_exit)

	def _clean_phase_exit(self, clean_phase):

		if self._default_exit(clean_phase) != os.EX_OK:
			self.wait()
			return

		pkg = self.pkg
		scheduler = self.scheduler
		settings = self.settings
		cleanup = 1

		# This initializes PORTAGE_LOG_FILE.
		portage.prepare_build_dirs(pkg.root, settings, cleanup)

		setup_phase = EbuildPhase(background=self.background,
			pkg=pkg, phase="setup", scheduler=scheduler,
			settings=settings, tree=self._tree)

		setup_phase.addExitListener(self._setup_exit)
		self._current_task = setup_phase
		self.scheduler.scheduleSetup(setup_phase)

	def _setup_exit(self, setup_phase):

		if self._default_exit(setup_phase) != os.EX_OK:
			self.wait()
			return

		unpack_phase = EbuildPhase(background=self.background,
			pkg=self.pkg, phase="unpack", scheduler=self.scheduler,
			settings=self.settings, tree=self._tree)

		if self._live_eclasses.intersection(self.pkg.inherited):
			# Serialize $DISTDIR access for live ebuilds since
			# otherwise they can interfere with eachother.

			unpack_phase.addExitListener(self._unpack_exit)
			self._current_task = unpack_phase
			self.scheduler.scheduleUnpack(unpack_phase)

		else:
			self._start_task(unpack_phase, self._unpack_exit)

	def _unpack_exit(self, unpack_phase):

		if self._default_exit(unpack_phase) != os.EX_OK:
			self.wait()
			return

		ebuild_phases = TaskSequence(scheduler=self.scheduler)

		pkg = self.pkg
		phases = self._phases
		eapi = pkg.metadata["EAPI"]
		if eapi in ("0", "1"):
			# skip src_prepare and src_configure
			phases = phases[2:]

		for phase in phases:
			ebuild_phases.add(EbuildPhase(background=self.background,
				pkg=self.pkg, phase=phase, scheduler=self.scheduler,
				settings=self.settings, tree=self._tree))

		self._start_task(ebuild_phases, self._default_final_exit)

class EbuildMetadataPhase(SubProcess):

	"""
	Asynchronous interface for the ebuild "depend" phase which is
	used to extract metadata from the ebuild.
	"""

	__slots__ = ("cpv", "ebuild_path", "fd_pipes", "metadata_callback",
		"ebuild_mtime", "portdb", "repo_path", "settings") + \
		("_raw_metadata",)

	_file_names = ("ebuild",)
	_files_dict = slot_dict_class(_file_names, prefix="")
	_metadata_fd = 9

	def _start(self):
		settings = self.settings
		settings.reset()
		ebuild_path = self.ebuild_path
		debug = settings.get("PORTAGE_DEBUG") == "1"
		master_fd = None
		slave_fd = None
		fd_pipes = None
		if self.fd_pipes is not None:
			fd_pipes = self.fd_pipes.copy()
		else:
			fd_pipes = {}

		fd_pipes.setdefault(0, sys.stdin.fileno())
		fd_pipes.setdefault(1, sys.stdout.fileno())
		fd_pipes.setdefault(2, sys.stderr.fileno())

		# flush any pending output
		for fd in fd_pipes.itervalues():
			if fd == sys.stdout.fileno():
				sys.stdout.flush()
			if fd == sys.stderr.fileno():
				sys.stderr.flush()

		fd_pipes_orig = fd_pipes.copy()
		self._files = self._files_dict()
		files = self._files

		master_fd, slave_fd = os.pipe()
		fcntl.fcntl(master_fd, fcntl.F_SETFL,
			fcntl.fcntl(master_fd, fcntl.F_GETFL) | os.O_NONBLOCK)

		fd_pipes[self._metadata_fd] = slave_fd

		self._raw_metadata = []
		files.ebuild = os.fdopen(master_fd, 'r')
		self._reg_id = self.scheduler.register(files.ebuild.fileno(),
			self._registered_events, self._output_handler)
		self._registered = True

		retval = portage.doebuild(ebuild_path, "depend",
			settings["ROOT"], settings, debug,
			mydbapi=self.portdb, tree="porttree",
			fd_pipes=fd_pipes, returnpid=True)

		os.close(slave_fd)

		if isinstance(retval, int):
			# doebuild failed before spawning
			self._unregister()
			self.returncode = retval
			self.wait()
			return

		self.pid = retval[0]
		portage.process.spawned_pids.remove(self.pid)

	def _output_handler(self, fd, event):

		if event & PollConstants.POLLIN:
			self._raw_metadata.append(self._files.ebuild.read())
			if not self._raw_metadata[-1]:
				self._unregister()
				self.wait()

		self._unregister_if_appropriate(event)
		return self._registered

	def _set_returncode(self, wait_retval):
		SubProcess._set_returncode(self, wait_retval)
		if self.returncode == os.EX_OK:
			metadata_lines = "".join(self._raw_metadata).splitlines()
			if len(portage.auxdbkeys) != len(metadata_lines):
				# Don't trust bash's returncode if the
				# number of lines is incorrect.
				self.returncode = 1
			else:
				metadata = izip(portage.auxdbkeys, metadata_lines)
				self.metadata_callback(self.cpv, self.ebuild_path,
					self.repo_path, metadata, self.ebuild_mtime)

class EbuildProcess(SpawnProcess):

	__slots__ = ("phase", "pkg", "settings", "tree")

	def _start(self):
		# Don't open the log file during the clean phase since the
		# open file can result in an nfs lock on $T/build.log which
		# prevents the clean phase from removing $T.
		if self.phase not in ("clean", "cleanrm"):
			self.logfile = self.settings.get("PORTAGE_LOG_FILE")
		SpawnProcess._start(self)

	def _pipe(self, fd_pipes):
		stdout_pipe = fd_pipes.get(1)
		got_pty, master_fd, slave_fd = \
			portage._create_pty_or_pipe(copy_term_size=stdout_pipe)
		return (master_fd, slave_fd)

	def _spawn(self, args, **kwargs):

		root_config = self.pkg.root_config
		tree = self.tree
		mydbapi = root_config.trees[tree].dbapi
		settings = self.settings
		ebuild_path = settings["EBUILD"]
		debug = settings.get("PORTAGE_DEBUG") == "1"

		rval = portage.doebuild(ebuild_path, self.phase,
			root_config.root, settings, debug,
			mydbapi=mydbapi, tree=tree, **kwargs)

		return rval

	def _set_returncode(self, wait_retval):
		SpawnProcess._set_returncode(self, wait_retval)

		if self.phase not in ("clean", "cleanrm"):
			self.returncode = portage._doebuild_exit_status_check_and_log(
				self.settings, self.phase, self.returncode)

		if self.phase == "test" and self.returncode != os.EX_OK and \
			"test-fail-continue" in self.settings.features:
			self.returncode = os.EX_OK

		portage._post_phase_userpriv_perms(self.settings)

class EbuildPhase(CompositeTask):

	__slots__ = ("background", "pkg", "phase",
		"scheduler", "settings", "tree")

	_post_phase_cmds = portage._post_phase_cmds

	def _start(self):

		ebuild_process = EbuildProcess(background=self.background,
			pkg=self.pkg, phase=self.phase, scheduler=self.scheduler,
			settings=self.settings, tree=self.tree)

		self._start_task(ebuild_process, self._ebuild_exit)

	def _ebuild_exit(self, ebuild_process):

		if self.phase == "install":
			out = None
			log_path = self.settings.get("PORTAGE_LOG_FILE")
			log_file = None
			if self.background and log_path is not None:
				log_file = open(log_path, 'a')
				out = log_file
			try:
				portage._check_build_log(self.settings, out=out)
			finally:
				if log_file is not None:
					log_file.close()

		if self._default_exit(ebuild_process) != os.EX_OK:
			self.wait()
			return

		settings = self.settings

		if self.phase == "install":
			portage._post_src_install_chost_fix(settings)
			portage._post_src_install_uid_fix(settings)

		post_phase_cmds = self._post_phase_cmds.get(self.phase)
		if post_phase_cmds is not None:
			post_phase = MiscFunctionsProcess(background=self.background,
				commands=post_phase_cmds, phase=self.phase, pkg=self.pkg,
				scheduler=self.scheduler, settings=settings)
			self._start_task(post_phase, self._post_phase_exit)
			return

		self.returncode = ebuild_process.returncode
		self._current_task = None
		self.wait()

	def _post_phase_exit(self, post_phase):
		if self._final_exit(post_phase) != os.EX_OK:
			writemsg("!!! post %s failed; exiting.\n" % self.phase,
				noiselevel=-1)
		self._current_task = None
		self.wait()
		return

class EbuildBinpkg(EbuildProcess):
	"""
	This assumes that src_install() has successfully completed.
	"""
	__slots__ = ("_binpkg_tmpfile",)

	def _start(self):
		self.phase = "package"
		self.tree = "porttree"
		pkg = self.pkg
		root_config = pkg.root_config
		portdb = root_config.trees["porttree"].dbapi
		bintree = root_config.trees["bintree"]
		ebuild_path = portdb.findname(self.pkg.cpv)
		settings = self.settings
		debug = settings.get("PORTAGE_DEBUG") == "1"

		bintree.prevent_collision(pkg.cpv)
		binpkg_tmpfile = os.path.join(bintree.pkgdir,
			pkg.cpv + ".tbz2." + str(os.getpid()))
		self._binpkg_tmpfile = binpkg_tmpfile
		settings["PORTAGE_BINPKG_TMPFILE"] = binpkg_tmpfile
		settings.backup_changes("PORTAGE_BINPKG_TMPFILE")

		try:
			EbuildProcess._start(self)
		finally:
			settings.pop("PORTAGE_BINPKG_TMPFILE", None)

	def _set_returncode(self, wait_retval):
		EbuildProcess._set_returncode(self, wait_retval)

		pkg = self.pkg
		bintree = pkg.root_config.trees["bintree"]
		binpkg_tmpfile = self._binpkg_tmpfile
		if self.returncode == os.EX_OK:
			bintree.inject(pkg.cpv, filename=binpkg_tmpfile)

class EbuildMerge(SlotObject):

	__slots__ = ("find_blockers", "logger", "ldpath_mtimes",
		"pkg", "pkg_count", "pkg_path", "pretend",
		"scheduler", "settings", "tree", "world_atom")

	def execute(self):
		root_config = self.pkg.root_config
		settings = self.settings
		retval = portage.merge(settings["CATEGORY"],
			settings["PF"], settings["D"],
			os.path.join(settings["PORTAGE_BUILDDIR"],
			"build-info"), root_config.root, settings,
			myebuild=settings["EBUILD"],
			mytree=self.tree, mydbapi=root_config.trees[self.tree].dbapi,
			vartree=root_config.trees["vartree"],
			prev_mtimes=self.ldpath_mtimes,
			scheduler=self.scheduler,
			blockers=self.find_blockers)

		if retval == os.EX_OK:
			self.world_atom(self.pkg)
			self._log_success()

		return retval

	def _log_success(self):
		pkg = self.pkg
		pkg_count = self.pkg_count
		pkg_path = self.pkg_path
		logger = self.logger
		if "noclean" not in self.settings.features:
			short_msg = "emerge: (%s of %s) %s Clean Post" % \
				(pkg_count.curval, pkg_count.maxval, pkg.cpv)
			logger.log((" === (%s of %s) " + \
				"Post-Build Cleaning (%s::%s)") % \
				(pkg_count.curval, pkg_count.maxval, pkg.cpv, pkg_path),
				short_msg=short_msg)
		logger.log(" ::: completed emerge (%s of %s) %s to %s" % \
			(pkg_count.curval, pkg_count.maxval, pkg.cpv, pkg.root))

class PackageUninstall(AsynchronousTask):

	__slots__ = ("ldpath_mtimes", "opts", "pkg", "scheduler", "settings")

	def _start(self):
		try:
			unmerge(self.pkg.root_config, self.opts, "unmerge",
				[self.pkg.cpv], self.ldpath_mtimes, clean_world=0,
				clean_delay=0, raise_on_error=1, scheduler=self.scheduler,
				writemsg_level=self._writemsg_level)
		except UninstallFailure, e:
			self.returncode = e.status
		else:
			self.returncode = os.EX_OK
		self.wait()

	def _writemsg_level(self, msg, level=0, noiselevel=0):

		log_path = self.settings.get("PORTAGE_LOG_FILE")
		background = self.background

		if log_path is None:
			if not (background and level < logging.WARNING):
				portage.util.writemsg_level(msg,
					level=level, noiselevel=noiselevel)
		else:
			if not background:
				portage.util.writemsg_level(msg,
					level=level, noiselevel=noiselevel)

			f = open(log_path, 'a')
			try:
				f.write(msg)
			finally:
				f.close()

class Binpkg(CompositeTask):

	__slots__ = ("find_blockers",
		"ldpath_mtimes", "logger", "opts",
		"pkg", "pkg_count", "prefetcher", "settings", "world_atom") + \
		("_bintree", "_build_dir", "_ebuild_path", "_fetched_pkg",
		"_image_dir", "_infloc", "_pkg_path", "_tree", "_verify")

	def _writemsg_level(self, msg, level=0, noiselevel=0):

		if not self.background:
			portage.util.writemsg_level(msg,
				level=level, noiselevel=noiselevel)

		log_path = self.settings.get("PORTAGE_LOG_FILE")
		if  log_path is not None:
			f = open(log_path, 'a')
			try:
				f.write(msg)
			finally:
				f.close()

	def _start(self):

		pkg = self.pkg
		settings = self.settings
		settings.setcpv(pkg)
		self._tree = "bintree"
		self._bintree = self.pkg.root_config.trees[self._tree]
		self._verify = not self.opts.pretend

		dir_path = os.path.join(settings["PORTAGE_TMPDIR"],
			"portage", pkg.category, pkg.pf)
		self._build_dir = EbuildBuildDir(dir_path=dir_path,
			pkg=pkg, settings=settings)
		self._image_dir = os.path.join(dir_path, "image")
		self._infloc = os.path.join(dir_path, "build-info")
		self._ebuild_path = os.path.join(self._infloc, pkg.pf + ".ebuild")
		settings["EBUILD"] = self._ebuild_path
		debug = settings.get("PORTAGE_DEBUG") == "1"
		portage.doebuild_environment(self._ebuild_path, "setup",
			settings["ROOT"], settings, debug, 1, self._bintree.dbapi)
		settings.configdict["pkg"]["EMERGE_FROM"] = pkg.type_name

		# The prefetcher has already completed or it
		# could be running now. If it's running now,
		# wait for it to complete since it holds
		# a lock on the file being fetched. The
		# portage.locks functions are only designed
		# to work between separate processes. Since
		# the lock is held by the current process,
		# use the scheduler and fetcher methods to
		# synchronize with the fetcher.
		prefetcher = self.prefetcher
		if prefetcher is None:
			pass
		elif not prefetcher.isAlive():
			prefetcher.cancel()
		elif prefetcher.poll() is None:

			waiting_msg = ("Fetching '%s' " + \
				"in the background. " + \
				"To view fetch progress, run `tail -f " + \
				"/var/log/emerge-fetch.log` in another " + \
				"terminal.") % prefetcher.pkg_path
			msg_prefix = colorize("GOOD", " * ")
			from textwrap import wrap
			waiting_msg = "".join("%s%s\n" % (msg_prefix, line) \
				for line in wrap(waiting_msg, 65))
			if not self.background:
				writemsg(waiting_msg, noiselevel=-1)

			self._current_task = prefetcher
			prefetcher.addExitListener(self._prefetch_exit)
			return

		self._prefetch_exit(prefetcher)

	def _prefetch_exit(self, prefetcher):

		pkg = self.pkg
		pkg_count = self.pkg_count
		if not (self.opts.pretend or self.opts.fetchonly):
			self._build_dir.lock()
			# If necessary, discard old log so that we don't
			# append to it.
			self._build_dir.clean_log()
			# Initialze PORTAGE_LOG_FILE.
			portage.prepare_build_dirs(self.settings["ROOT"], self.settings, 1)
		fetcher = BinpkgFetcher(background=self.background,
			logfile=self.settings.get("PORTAGE_LOG_FILE"), pkg=self.pkg,
			pretend=self.opts.pretend, scheduler=self.scheduler)
		pkg_path = fetcher.pkg_path
		self._pkg_path = pkg_path

		if self.opts.getbinpkg and self._bintree.isremote(pkg.cpv):

			msg = " --- (%s of %s) Fetching Binary (%s::%s)" %\
				(pkg_count.curval, pkg_count.maxval, pkg.cpv, pkg_path)
			short_msg = "emerge: (%s of %s) %s Fetch" % \
				(pkg_count.curval, pkg_count.maxval, pkg.cpv)
			self.logger.log(msg, short_msg=short_msg)
			self._start_task(fetcher, self._fetcher_exit)
			return

		self._fetcher_exit(fetcher)

	def _fetcher_exit(self, fetcher):

		# The fetcher only has a returncode when
		# --getbinpkg is enabled.
		if fetcher.returncode is not None:
			self._fetched_pkg = True
			if self._default_exit(fetcher) != os.EX_OK:
				self._unlock_builddir()
				self.wait()
				return

		if self.opts.pretend:
			self._current_task = None
			self.returncode = os.EX_OK
			self.wait()
			return

		verifier = None
		if self._verify:
			logfile = None
			if self.background:
				logfile = self.settings.get("PORTAGE_LOG_FILE")
			verifier = BinpkgVerifier(background=self.background,
				logfile=logfile, pkg=self.pkg)
			self._start_task(verifier, self._verifier_exit)
			return

		self._verifier_exit(verifier)

	def _verifier_exit(self, verifier):
		if verifier is not None and \
			self._default_exit(verifier) != os.EX_OK:
			self._unlock_builddir()
			self.wait()
			return

		logger = self.logger
		pkg = self.pkg
		pkg_count = self.pkg_count
		pkg_path = self._pkg_path

		if self._fetched_pkg:
			self._bintree.inject(pkg.cpv, filename=pkg_path)

		if self.opts.fetchonly:
			self._current_task = None
			self.returncode = os.EX_OK
			self.wait()
			return

		msg = " === (%s of %s) Merging Binary (%s::%s)" % \
			(pkg_count.curval, pkg_count.maxval, pkg.cpv, pkg_path)
		short_msg = "emerge: (%s of %s) %s Merge Binary" % \
			(pkg_count.curval, pkg_count.maxval, pkg.cpv)
		logger.log(msg, short_msg=short_msg)

		phase = "clean"
		settings = self.settings
		ebuild_phase = EbuildPhase(background=self.background,
			pkg=pkg, phase=phase, scheduler=self.scheduler,
			settings=settings, tree=self._tree)

		self._start_task(ebuild_phase, self._clean_exit)

	def _clean_exit(self, clean_phase):
		if self._default_exit(clean_phase) != os.EX_OK:
			self._unlock_builddir()
			self.wait()
			return

		dir_path = self._build_dir.dir_path

		infloc = self._infloc
		pkg = self.pkg
		pkg_path = self._pkg_path

		dir_mode = 0755
		for mydir in (dir_path, self._image_dir, infloc):
			portage.util.ensure_dirs(mydir, uid=portage.data.portage_uid,
				gid=portage.data.portage_gid, mode=dir_mode)

		# This initializes PORTAGE_LOG_FILE.
		portage.prepare_build_dirs(self.settings["ROOT"], self.settings, 1)
		self._writemsg_level(">>> Extracting info\n")

		pkg_xpak = portage.xpak.tbz2(self._pkg_path)
		check_missing_metadata = ("CATEGORY", "PF")
		missing_metadata = set()
		for k in check_missing_metadata:
			v = pkg_xpak.getfile(k)
			if not v:
				missing_metadata.add(k)

		pkg_xpak.unpackinfo(infloc)
		for k in missing_metadata:
			if k == "CATEGORY":
				v = pkg.category
			elif k == "PF":
				v = pkg.pf
			else:
				continue

			f = open(os.path.join(infloc, k), 'wb')
			try:
				f.write(v + "\n")
			finally:
				f.close()

		# Store the md5sum in the vdb.
		f = open(os.path.join(infloc, "BINPKGMD5"), "w")
		try:
			f.write(str(portage.checksum.perform_md5(pkg_path)) + "\n")
		finally:
			f.close()

		# This gives bashrc users an opportunity to do various things
		# such as remove binary packages after they're installed.
		settings = self.settings
		settings.setcpv(self.pkg)
		settings["PORTAGE_BINPKG_FILE"] = pkg_path
		settings.backup_changes("PORTAGE_BINPKG_FILE")

		phase = "setup"
		setup_phase = EbuildPhase(background=self.background,
			pkg=self.pkg, phase=phase, scheduler=self.scheduler,
			settings=settings, tree=self._tree)

		setup_phase.addExitListener(self._setup_exit)
		self._current_task = setup_phase
		self.scheduler.scheduleSetup(setup_phase)

	def _setup_exit(self, setup_phase):
		if self._default_exit(setup_phase) != os.EX_OK:
			self._unlock_builddir()
			self.wait()
			return

		extractor = BinpkgExtractorAsync(background=self.background,
			image_dir=self._image_dir,
			pkg=self.pkg, pkg_path=self._pkg_path, scheduler=self.scheduler)
		self._writemsg_level(">>> Extracting %s\n" % self.pkg.cpv)
		self._start_task(extractor, self._extractor_exit)

	def _extractor_exit(self, extractor):
		if self._final_exit(extractor) != os.EX_OK:
			self._unlock_builddir()
			writemsg("!!! Error Extracting '%s'\n" % self._pkg_path,
				noiselevel=-1)
		self.wait()

	def _unlock_builddir(self):
		if self.opts.pretend or self.opts.fetchonly:
			return
		portage.elog.elog_process(self.pkg.cpv, self.settings)
		self._build_dir.unlock()

	def install(self):

		# This gives bashrc users an opportunity to do various things
		# such as remove binary packages after they're installed.
		settings = self.settings
		settings["PORTAGE_BINPKG_FILE"] = self._pkg_path
		settings.backup_changes("PORTAGE_BINPKG_FILE")

		merge = EbuildMerge(find_blockers=self.find_blockers,
			ldpath_mtimes=self.ldpath_mtimes, logger=self.logger,
			pkg=self.pkg, pkg_count=self.pkg_count,
			pkg_path=self._pkg_path, scheduler=self.scheduler,
			settings=settings, tree=self._tree, world_atom=self.world_atom)

		try:
			retval = merge.execute()
		finally:
			settings.pop("PORTAGE_BINPKG_FILE", None)
			self._unlock_builddir()
		return retval

class BinpkgFetcher(SpawnProcess):

	__slots__ = ("pkg", "pretend",
		"locked", "pkg_path", "_lock_obj")

	def __init__(self, **kwargs):
		SpawnProcess.__init__(self, **kwargs)
		pkg = self.pkg
		self.pkg_path = pkg.root_config.trees["bintree"].getname(pkg.cpv)

	def _start(self):

		if self.cancelled:
			return

		pkg = self.pkg
		pretend = self.pretend
		bintree = pkg.root_config.trees["bintree"]
		settings = bintree.settings
		use_locks = "distlocks" in settings.features
		pkg_path = self.pkg_path

		if not pretend:
			portage.util.ensure_dirs(os.path.dirname(pkg_path))
			if use_locks:
				self.lock()
		exists = os.path.exists(pkg_path)
		resume = exists and os.path.basename(pkg_path) in bintree.invalids
		if not (pretend or resume):
			# Remove existing file or broken symlink.
			try:
				os.unlink(pkg_path)
			except OSError:
				pass

		# urljoin doesn't work correctly with
		# unrecognized protocols like sftp
		if bintree._remote_has_index:
			rel_uri = bintree._remotepkgs[pkg.cpv].get("PATH")
			if not rel_uri:
				rel_uri = pkg.cpv + ".tbz2"
			uri = bintree._remote_base_uri.rstrip("/") + \
				"/" + rel_uri.lstrip("/")
		else:
			uri = settings["PORTAGE_BINHOST"].rstrip("/") + \
				"/" + pkg.pf + ".tbz2"

		if pretend:
			portage.writemsg_stdout("\n%s\n" % uri, noiselevel=-1)
			self.returncode = os.EX_OK
			self.wait()
			return

		protocol = urlparse.urlparse(uri)[0]
		fcmd_prefix = "FETCHCOMMAND"
		if resume:
			fcmd_prefix = "RESUMECOMMAND"
		fcmd = settings.get(fcmd_prefix + "_" + protocol.upper())
		if not fcmd:
			fcmd = settings.get(fcmd_prefix)

		fcmd_vars = {
			"DISTDIR" : os.path.dirname(pkg_path),
			"URI"     : uri,
			"FILE"    : os.path.basename(pkg_path)
		}

		fetch_env = dict(settings.iteritems())
		fetch_args = [portage.util.varexpand(x, mydict=fcmd_vars) \
			for x in shlex.split(fcmd)]

		if self.fd_pipes is None:
			self.fd_pipes = {}
		fd_pipes = self.fd_pipes

		# Redirect all output to stdout since some fetchers like
		# wget pollute stderr (if portage detects a problem then it
		# can send it's own message to stderr).
		fd_pipes.setdefault(0, sys.stdin.fileno())
		fd_pipes.setdefault(1, sys.stdout.fileno())
		fd_pipes.setdefault(2, sys.stdout.fileno())

		self.args = fetch_args
		self.env = fetch_env
		SpawnProcess._start(self)

	def _set_returncode(self, wait_retval):
		SpawnProcess._set_returncode(self, wait_retval)
		if self.returncode == os.EX_OK:
			# If possible, update the mtime to match the remote package if
			# the fetcher didn't already do it automatically.
			bintree = self.pkg.root_config.trees["bintree"]
			if bintree._remote_has_index:
				remote_mtime = bintree._remotepkgs[self.pkg.cpv].get("MTIME")
				if remote_mtime is not None:
					try:
						remote_mtime = long(remote_mtime)
					except ValueError:
						pass
					else:
						try:
							local_mtime = long(os.stat(self.pkg_path).st_mtime)
						except OSError:
							pass
						else:
							if remote_mtime != local_mtime:
								try:
									os.utime(self.pkg_path,
										(remote_mtime, remote_mtime))
								except OSError:
									pass

		if self.locked:
			self.unlock()

	def lock(self):
		"""
		This raises an AlreadyLocked exception if lock() is called
		while a lock is already held. In order to avoid this, call
		unlock() or check whether the "locked" attribute is True
		or False before calling lock().
		"""
		if self._lock_obj is not None:
			raise self.AlreadyLocked((self._lock_obj,))

		self._lock_obj = portage.locks.lockfile(
			self.pkg_path, wantnewlockfile=1)
		self.locked = True

	class AlreadyLocked(portage.exception.PortageException):
		pass

	def unlock(self):
		if self._lock_obj is None:
			return
		portage.locks.unlockfile(self._lock_obj)
		self._lock_obj = None
		self.locked = False

class BinpkgVerifier(AsynchronousTask):
	__slots__ = ("logfile", "pkg",)

	def _start(self):
		"""
		Note: Unlike a normal AsynchronousTask.start() method,
		this one does all work is synchronously. The returncode
		attribute will be set before it returns.
		"""

		pkg = self.pkg
		root_config = pkg.root_config
		bintree = root_config.trees["bintree"]
		rval = os.EX_OK
		stdout_orig = sys.stdout
		stderr_orig = sys.stderr
		log_file = None
		if self.background and self.logfile is not None:
			log_file = open(self.logfile, 'a')
		try:
			if log_file is not None:
				sys.stdout = log_file
				sys.stderr = log_file
			try:
				bintree.digestCheck(pkg)
			except portage.exception.FileNotFound:
				writemsg("!!! Fetching Binary failed " + \
					"for '%s'\n" % pkg.cpv, noiselevel=-1)
				rval = 1
			except portage.exception.DigestException, e:
				writemsg("\n!!! Digest verification failed:\n",
					noiselevel=-1)
				writemsg("!!! %s\n" % e.value[0],
					noiselevel=-1)
				writemsg("!!! Reason: %s\n" % e.value[1],
					noiselevel=-1)
				writemsg("!!! Got: %s\n" % e.value[2],
					noiselevel=-1)
				writemsg("!!! Expected: %s\n" % e.value[3],
					noiselevel=-1)
				rval = 1
			if rval != os.EX_OK:
				pkg_path = bintree.getname(pkg.cpv)
				head, tail = os.path.split(pkg_path)
				temp_filename = portage._checksum_failure_temp_file(head, tail)
				writemsg("File renamed to '%s'\n" % (temp_filename,),
					noiselevel=-1)
		finally:
			sys.stdout = stdout_orig
			sys.stderr = stderr_orig
			if log_file is not None:
				log_file.close()

		self.returncode = rval
		self.wait()

class BinpkgPrefetcher(CompositeTask):

	__slots__ = ("pkg",) + \
		("pkg_path", "_bintree",)

	def _start(self):
		self._bintree = self.pkg.root_config.trees["bintree"]
		fetcher = BinpkgFetcher(background=self.background,
			logfile=self.scheduler.fetch.log_file, pkg=self.pkg,
			scheduler=self.scheduler)
		self.pkg_path = fetcher.pkg_path
		self._start_task(fetcher, self._fetcher_exit)

	def _fetcher_exit(self, fetcher):

		if self._default_exit(fetcher) != os.EX_OK:
			self.wait()
			return

		verifier = BinpkgVerifier(background=self.background,
			logfile=self.scheduler.fetch.log_file, pkg=self.pkg)
		self._start_task(verifier, self._verifier_exit)

	def _verifier_exit(self, verifier):
		if self._default_exit(verifier) != os.EX_OK:
			self.wait()
			return

		self._bintree.inject(self.pkg.cpv, filename=self.pkg_path)

		self._current_task = None
		self.returncode = os.EX_OK
		self.wait()

class BinpkgExtractorAsync(SpawnProcess):

	__slots__ = ("image_dir", "pkg", "pkg_path")

	_shell_binary = portage.const.BASH_BINARY

	def _start(self):
		self.args = [self._shell_binary, "-c",
			"bzip2 -dqc -- %s | tar -xp -C %s -f -" % \
			(portage._shell_quote(self.pkg_path),
			portage._shell_quote(self.image_dir))]

		self.env = self.pkg.root_config.settings.environ()
		SpawnProcess._start(self)

class MergeListItem(CompositeTask):

	"""
	TODO: For parallel scheduling, everything here needs asynchronous
	execution support (start, poll, and wait methods).
	"""

	__slots__ = ("args_set",
		"binpkg_opts", "build_opts", "config_pool", "emerge_opts",
		"find_blockers", "logger", "mtimedb", "pkg",
		"pkg_count", "pkg_to_replace", "prefetcher",
		"settings", "statusMessage", "world_atom") + \
		("_install_task",)

	def _start(self):

		pkg = self.pkg
		build_opts = self.build_opts

		if pkg.installed:
			# uninstall,  executed by self.merge()
			self.returncode = os.EX_OK
			self.wait()
			return

		args_set = self.args_set
		find_blockers = self.find_blockers
		logger = self.logger
		mtimedb = self.mtimedb
		pkg_count = self.pkg_count
		scheduler = self.scheduler
		settings = self.settings
		world_atom = self.world_atom
		ldpath_mtimes = mtimedb["ldpath"]

		action_desc = "Emerging"
		preposition = "for"
		if pkg.type_name == "binary":
			action_desc += " binary"

		if build_opts.fetchonly:
			action_desc = "Fetching"

		msg = "%s (%s of %s) %s" % \
			(action_desc,
			colorize("MERGE_LIST_PROGRESS", str(pkg_count.curval)),
			colorize("MERGE_LIST_PROGRESS", str(pkg_count.maxval)),
			colorize("GOOD", pkg.cpv))

		portdb = pkg.root_config.trees["porttree"].dbapi
		portdir_repo_name = portdb._repository_map.get(portdb.porttree_root)
		if portdir_repo_name:
			pkg_repo_name = pkg.metadata.get("repository")
			if pkg_repo_name != portdir_repo_name:
				if not pkg_repo_name:
					pkg_repo_name = "unknown repo"
				msg += " from %s" % pkg_repo_name

		if pkg.root != "/":
			msg += " %s %s" % (preposition, pkg.root)

		if not build_opts.pretend:
			self.statusMessage(msg)
			logger.log(" >>> emerge (%s of %s) %s to %s" % \
				(pkg_count.curval, pkg_count.maxval, pkg.cpv, pkg.root))

		if pkg.type_name == "ebuild":

			build = EbuildBuild(args_set=args_set,
				background=self.background,
				config_pool=self.config_pool,
				find_blockers=find_blockers,
				ldpath_mtimes=ldpath_mtimes, logger=logger,
				opts=build_opts, pkg=pkg, pkg_count=pkg_count,
				prefetcher=self.prefetcher, scheduler=scheduler,
				settings=settings, world_atom=world_atom)

			self._install_task = build
			self._start_task(build, self._default_final_exit)
			return

		elif pkg.type_name == "binary":

			binpkg = Binpkg(background=self.background,
				find_blockers=find_blockers,
				ldpath_mtimes=ldpath_mtimes, logger=logger,
				opts=self.binpkg_opts, pkg=pkg, pkg_count=pkg_count,
				prefetcher=self.prefetcher, settings=settings,
				scheduler=scheduler, world_atom=world_atom)

			self._install_task = binpkg
			self._start_task(binpkg, self._default_final_exit)
			return

	def _poll(self):
		self._install_task.poll()
		return self.returncode

	def _wait(self):
		self._install_task.wait()
		return self.returncode

	def merge(self):

		pkg = self.pkg
		build_opts = self.build_opts
		find_blockers = self.find_blockers
		logger = self.logger
		mtimedb = self.mtimedb
		pkg_count = self.pkg_count
		prefetcher = self.prefetcher
		scheduler = self.scheduler
		settings = self.settings
		world_atom = self.world_atom
		ldpath_mtimes = mtimedb["ldpath"]

		if pkg.installed:
			if not (build_opts.buildpkgonly or \
				build_opts.fetchonly or build_opts.pretend):

				uninstall = PackageUninstall(background=self.background,
					ldpath_mtimes=ldpath_mtimes, opts=self.emerge_opts,
					pkg=pkg, scheduler=scheduler, settings=settings)

				uninstall.start()
				retval = uninstall.wait()
				if retval != os.EX_OK:
					return retval
			return os.EX_OK

		if build_opts.fetchonly or \
			build_opts.buildpkgonly:
			return self.returncode

		retval = self._install_task.install()
		return retval

class PackageMerge(AsynchronousTask):
	"""
	TODO: Implement asynchronous merge so that the scheduler can
	run while a merge is executing.
	"""

	__slots__ = ("merge",)

	def _start(self):

		pkg = self.merge.pkg
		pkg_count = self.merge.pkg_count

		if pkg.installed:
			action_desc = "Uninstalling"
			preposition = "from"
		else:
			action_desc = "Installing"
			preposition = "to"

		msg = "%s %s" % (action_desc, colorize("GOOD", pkg.cpv))

		if pkg.root != "/":
			msg += " %s %s" % (preposition, pkg.root)

		if not self.merge.build_opts.fetchonly and \
			not self.merge.build_opts.pretend and \
			not self.merge.build_opts.buildpkgonly:
			self.merge.statusMessage(msg)

		self.returncode = self.merge.merge()
		self.wait()

class DependencyArg(object):
	def __init__(self, arg=None, root_config=None):
		self.arg = arg
		self.root_config = root_config

	def __str__(self):
		return str(self.arg)

class AtomArg(DependencyArg):
	def __init__(self, atom=None, **kwargs):
		DependencyArg.__init__(self, **kwargs)
		self.atom = atom
		if not isinstance(self.atom, portage.dep.Atom):
			self.atom = portage.dep.Atom(self.atom)
		self.set = (self.atom, )

class PackageArg(DependencyArg):
	def __init__(self, package=None, **kwargs):
		DependencyArg.__init__(self, **kwargs)
		self.package = package
		self.atom = portage.dep.Atom("=" + package.cpv)
		self.set = (self.atom, )

class SetArg(DependencyArg):
	def __init__(self, set=None, **kwargs):
		DependencyArg.__init__(self, **kwargs)
		self.set = set
		self.name = self.arg[len(SETPREFIX):]

class Dependency(SlotObject):
	__slots__ = ("atom", "blocker", "depth",
		"parent", "onlydeps", "priority", "root")
	def __init__(self, **kwargs):
		SlotObject.__init__(self, **kwargs)
		if self.priority is None:
			self.priority = DepPriority()
		if self.depth is None:
			self.depth = 0

class BlockerCache(portage.cache.mappings.MutableMapping):
	"""This caches blockers of installed packages so that dep_check does not
	have to be done for every single installed package on every invocation of
	emerge.  The cache is invalidated whenever it is detected that something
	has changed that might alter the results of dep_check() calls:
		1) the set of installed packages (including COUNTER) has changed
		2) the old-style virtuals have changed
	"""

	# Number of uncached packages to trigger cache update, since
	# it's wasteful to update it for every vdb change.
	_cache_threshold = 5

	class BlockerData(object):

		__slots__ = ("__weakref__", "atoms", "counter")

		def __init__(self, counter, atoms):
			self.counter = counter
			self.atoms = atoms

	def __init__(self, myroot, vardb):
		self._vardb = vardb
		self._virtuals = vardb.settings.getvirtuals()
		self._cache_filename = os.path.join(myroot,
			portage.CACHE_PATH.lstrip(os.path.sep), "vdb_blockers.pickle")
		self._cache_version = "1"
		self._cache_data = None
		self._modified = set()
		self._load()

	def _load(self):
		try:
			f = open(self._cache_filename, mode='rb')
			mypickle = pickle.Unpickler(f)
			try:
				mypickle.find_global = None
			except AttributeError:
				# TODO: If py3k, override Unpickler.find_class().
				pass
			self._cache_data = mypickle.load()
			f.close()
			del f
		except (IOError, OSError, EOFError, ValueError, pickle.UnpicklingError), e:
			if isinstance(e, pickle.UnpicklingError):
				writemsg("!!! Error loading '%s': %s\n" % \
					(self._cache_filename, str(e)), noiselevel=-1)
			del e

		cache_valid = self._cache_data and \
			isinstance(self._cache_data, dict) and \
			self._cache_data.get("version") == self._cache_version and \
			isinstance(self._cache_data.get("blockers"), dict)
		if cache_valid:
			# Validate all the atoms and counters so that
			# corruption is detected as soon as possible.
			invalid_items = set()
			for k, v in self._cache_data["blockers"].iteritems():
				if not isinstance(k, basestring):
					invalid_items.add(k)
					continue
				try:
					if portage.catpkgsplit(k) is None:
						invalid_items.add(k)
						continue
				except portage.exception.InvalidData:
					invalid_items.add(k)
					continue
				if not isinstance(v, tuple) or \
					len(v) != 2:
					invalid_items.add(k)
					continue
				counter, atoms = v
				if not isinstance(counter, (int, long)):
					invalid_items.add(k)
					continue
				if not isinstance(atoms, (list, tuple)):
					invalid_items.add(k)
					continue
				invalid_atom = False
				for atom in atoms:
					if not isinstance(atom, basestring):
						invalid_atom = True
						break
					if atom[:1] != "!" or \
						not portage.isvalidatom(
						atom, allow_blockers=True):
						invalid_atom = True
						break
				if invalid_atom:
					invalid_items.add(k)
					continue

			for k in invalid_items:
				del self._cache_data["blockers"][k]
			if not self._cache_data["blockers"]:
				cache_valid = False

		if not cache_valid:
			self._cache_data = {"version":self._cache_version}
			self._cache_data["blockers"] = {}
			self._cache_data["virtuals"] = self._virtuals
		self._modified.clear()

	def flush(self):
		"""If the current user has permission and the internal blocker cache
		been updated, save it to disk and mark it unmodified.  This is called
		by emerge after it has proccessed blockers for all installed packages.
		Currently, the cache is only written if the user has superuser
		privileges (since that's required to obtain a lock), but all users
		have read access and benefit from faster blocker lookups (as long as
		the entire cache is still valid).  The cache is stored as a pickled
		dict object with the following format:

		{
			version : "1",
			"blockers" : {cpv1:(counter,(atom1, atom2...)), cpv2...},
			"virtuals" : vardb.settings.getvirtuals()
		}
		"""
		if len(self._modified) >= self._cache_threshold and \
			secpass >= 2:
			try:
				f = portage.util.atomic_ofstream(self._cache_filename, mode='wb')
				pickle.dump(self._cache_data, f, protocol=2)
				f.close()
				portage.util.apply_secpass_permissions(
					self._cache_filename, gid=portage.portage_gid, mode=0644)
			except (IOError, OSError), e:
				pass
			self._modified.clear()

	def __setitem__(self, cpv, blocker_data):
		"""
		Update the cache and mark it as modified for a future call to
		self.flush().

		@param cpv: Package for which to cache blockers.
		@type cpv: String
		@param blocker_data: An object with counter and atoms attributes.
		@type blocker_data: BlockerData
		"""
		self._cache_data["blockers"][cpv] = \
			(blocker_data.counter, tuple(str(x) for x in blocker_data.atoms))
		self._modified.add(cpv)

	def __iter__(self):
		if self._cache_data is None:
			# triggered by python-trace
			return iter([])
		return iter(self._cache_data["blockers"])

	def __delitem__(self, cpv):
		del self._cache_data["blockers"][cpv]

	def __getitem__(self, cpv):
		"""
		@rtype: BlockerData
		@returns: An object with counter and atoms attributes.
		"""
		return self.BlockerData(*self._cache_data["blockers"][cpv])

class BlockerDB(object):

	def __init__(self, root_config):
		self._root_config = root_config
		self._vartree = root_config.trees["vartree"]
		self._portdb = root_config.trees["porttree"].dbapi

		self._dep_check_trees = None
		self._fake_vartree = None

	def _get_fake_vartree(self, acquire_lock=0):
		fake_vartree = self._fake_vartree
		if fake_vartree is None:
			fake_vartree = FakeVartree(self._root_config,
				acquire_lock=acquire_lock)
			self._fake_vartree = fake_vartree
			self._dep_check_trees = { self._vartree.root : {
				"porttree"    :  fake_vartree,
				"vartree"     :  fake_vartree,
			}}
		else:
			fake_vartree.sync(acquire_lock=acquire_lock)
		return fake_vartree

	def findInstalledBlockers(self, new_pkg, acquire_lock=0):
		blocker_cache = BlockerCache(self._vartree.root, self._vartree.dbapi)
		dep_keys = ["DEPEND", "RDEPEND", "PDEPEND"]
		settings = self._vartree.settings
		stale_cache = set(blocker_cache)
		fake_vartree = self._get_fake_vartree(acquire_lock=acquire_lock)
		dep_check_trees = self._dep_check_trees
		vardb = fake_vartree.dbapi
		installed_pkgs = list(vardb)

		for inst_pkg in installed_pkgs:
			stale_cache.discard(inst_pkg.cpv)
			cached_blockers = blocker_cache.get(inst_pkg.cpv)
			if cached_blockers is not None and \
				cached_blockers.counter != long(inst_pkg.metadata["COUNTER"]):
				cached_blockers = None
			if cached_blockers is not None:
				blocker_atoms = cached_blockers.atoms
			else:
				# Use aux_get() to trigger FakeVartree global
				# updates on *DEPEND when appropriate.
				depstr = " ".join(vardb.aux_get(inst_pkg.cpv, dep_keys))
				try:
					portage.dep._dep_check_strict = False
					success, atoms = portage.dep_check(depstr,
						vardb, settings, myuse=inst_pkg.use.enabled,
						trees=dep_check_trees, myroot=inst_pkg.root)
				finally:
					portage.dep._dep_check_strict = True
				if not success:
					pkg_location = os.path.join(inst_pkg.root,
						portage.VDB_PATH, inst_pkg.category, inst_pkg.pf)
					portage.writemsg("!!! %s/*DEPEND: %s\n" % \
						(pkg_location, atoms), noiselevel=-1)
					continue

				blocker_atoms = [atom for atom in atoms \
					if atom.startswith("!")]
				blocker_atoms.sort()
				counter = long(inst_pkg.metadata["COUNTER"])
				blocker_cache[inst_pkg.cpv] = \
					blocker_cache.BlockerData(counter, blocker_atoms)
		for cpv in stale_cache:
			del blocker_cache[cpv]
		blocker_cache.flush()

		blocker_parents = digraph()
		blocker_atoms = []
		for pkg in installed_pkgs:
			for blocker_atom in blocker_cache[pkg.cpv].atoms:
				blocker_atom = blocker_atom.lstrip("!")
				blocker_atoms.append(blocker_atom)
				blocker_parents.add(blocker_atom, pkg)

		blocker_atoms = InternalPackageSet(initial_atoms=blocker_atoms)
		blocking_pkgs = set()
		for atom in blocker_atoms.iterAtomsForPackage(new_pkg):
			blocking_pkgs.update(blocker_parents.parent_nodes(atom))

		# Check for blockers in the other direction.
		depstr = " ".join(new_pkg.metadata[k] for k in dep_keys)
		try:
			portage.dep._dep_check_strict = False
			success, atoms = portage.dep_check(depstr,
				vardb, settings, myuse=new_pkg.use.enabled,
				trees=dep_check_trees, myroot=new_pkg.root)
		finally:
			portage.dep._dep_check_strict = True
		if not success:
			# We should never get this far with invalid deps.
			show_invalid_depstring_notice(new_pkg, depstr, atoms)
			assert False

		blocker_atoms = [atom.lstrip("!") for atom in atoms \
			if atom[:1] == "!"]
		if blocker_atoms:
			blocker_atoms = InternalPackageSet(initial_atoms=blocker_atoms)
			for inst_pkg in installed_pkgs:
				try:
					blocker_atoms.iterAtomsForPackage(inst_pkg).next()
				except (portage.exception.InvalidDependString, StopIteration):
					continue
				blocking_pkgs.add(inst_pkg)

		return blocking_pkgs

def show_invalid_depstring_notice(parent_node, depstring, error_msg):

	msg1 = "\n\n!!! Invalid or corrupt dependency specification: " + \
		"\n\n%s\n\n%s\n\n%s\n\n" % (error_msg, parent_node, depstring)
	p_type, p_root, p_key, p_status = parent_node
	msg = []
	if p_status == "nomerge":
		category, pf = portage.catsplit(p_key)
		pkg_location = os.path.join(p_root, portage.VDB_PATH, category, pf)
		msg.append("Portage is unable to process the dependencies of the ")
		msg.append("'%s' package. " % p_key)
		msg.append("In order to correct this problem, the package ")
		msg.append("should be uninstalled, reinstalled, or upgraded. ")
		msg.append("As a temporary workaround, the --nodeps option can ")
		msg.append("be used to ignore all dependencies.  For reference, ")
		msg.append("the problematic dependencies can be found in the ")
		msg.append("*DEPEND files located in '%s/'." % pkg_location)
	else:
		msg.append("This package can not be installed. ")
		msg.append("Please notify the '%s' package maintainer " % p_key)
		msg.append("about this problem.")

	msg2 = "".join("%s\n" % line for line in textwrap.wrap("".join(msg), 72))
	writemsg_level(msg1 + msg2, level=logging.ERROR, noiselevel=-1)

class PackageVirtualDbapi(portage.dbapi):
	"""
	A dbapi-like interface class that represents the state of the installed
	package database as new packages are installed, replacing any packages
	that previously existed in the same slot. The main difference between
	this class and fakedbapi is that this one uses Package instances
	internally (passed in via cpv_inject() and cpv_remove() calls).
	"""
	def __init__(self, settings):
		portage.dbapi.__init__(self)
		self.settings = settings
		self._match_cache = {}
		self._cp_map = {}
		self._cpv_map = {}

	def clear(self):
		"""
		Remove all packages.
		"""
		if self._cpv_map:
			self._clear_cache()
			self._cp_map.clear()
			self._cpv_map.clear()

	def copy(self):
		obj = PackageVirtualDbapi(self.settings)
		obj._match_cache = self._match_cache.copy()
		obj._cp_map = self._cp_map.copy()
		for k, v in obj._cp_map.iteritems():
			obj._cp_map[k] = v[:]
		obj._cpv_map = self._cpv_map.copy()
		return obj

	def __iter__(self):
		return self._cpv_map.itervalues()

	def __contains__(self, item):
		existing = self._cpv_map.get(item.cpv)
		if existing is not None and \
			existing == item:
			return True
		return False

	def get(self, item, default=None):
		cpv = getattr(item, "cpv", None)
		if cpv is None:
			if len(item) != 4:
				return default
			type_name, root, cpv, operation = item

		existing = self._cpv_map.get(cpv)
		if existing is not None and \
			existing == item:
			return existing
		return default

	def match_pkgs(self, atom):
		return [self._cpv_map[cpv] for cpv in self.match(atom)]

	def _clear_cache(self):
		if self._categories is not None:
			self._categories = None
		if self._match_cache:
			self._match_cache = {}

	def match(self, origdep, use_cache=1):
		result = self._match_cache.get(origdep)
		if result is not None:
			return result[:]
		result = portage.dbapi.match(self, origdep, use_cache=use_cache)
		self._match_cache[origdep] = result
		return result[:]

	def cpv_exists(self, cpv):
		return cpv in self._cpv_map

	def cp_list(self, mycp, use_cache=1):
		cachelist = self._match_cache.get(mycp)
		# cp_list() doesn't expand old-style virtuals
		if cachelist and cachelist[0].startswith(mycp):
			return cachelist[:]
		cpv_list = self._cp_map.get(mycp)
		if cpv_list is None:
			cpv_list = []
		else:
			cpv_list = [pkg.cpv for pkg in cpv_list]
		self._cpv_sort_ascending(cpv_list)
		if not (not cpv_list and mycp.startswith("virtual/")):
			self._match_cache[mycp] = cpv_list
		return cpv_list[:]

	def cp_all(self):
		return list(self._cp_map)

	def cpv_all(self):
		return list(self._cpv_map)

	def cpv_inject(self, pkg):
		cp_list = self._cp_map.get(pkg.cp)
		if cp_list is None:
			cp_list = []
			self._cp_map[pkg.cp] = cp_list
		e_pkg = self._cpv_map.get(pkg.cpv)
		if e_pkg is not None:
			if e_pkg == pkg:
				return
			self.cpv_remove(e_pkg)
		for e_pkg in cp_list:
			if e_pkg.slot_atom == pkg.slot_atom:
				if e_pkg == pkg:
					return
				self.cpv_remove(e_pkg)
				break
		cp_list.append(pkg)
		self._cpv_map[pkg.cpv] = pkg
		self._clear_cache()

	def cpv_remove(self, pkg):
		old_pkg = self._cpv_map.get(pkg.cpv)
		if old_pkg != pkg:
			raise KeyError(pkg)
		self._cp_map[pkg.cp].remove(pkg)
		del self._cpv_map[pkg.cpv]
		self._clear_cache()

	def aux_get(self, cpv, wants):
		metadata = self._cpv_map[cpv].metadata
		return [metadata.get(x, "") for x in wants]

	def aux_update(self, cpv, values):
		self._cpv_map[cpv].metadata.update(values)
		self._clear_cache()

class depgraph(object):

	pkg_tree_map = RootConfig.pkg_tree_map

	_dep_keys = ["DEPEND", "RDEPEND", "PDEPEND"]

	def __init__(self, settings, trees, myopts, myparams, spinner):
		self.settings = settings
		self.target_root = settings["ROOT"]
		self.myopts = myopts
		self.myparams = myparams
		self.edebug = 0
		if settings.get("PORTAGE_DEBUG", "") == "1":
			self.edebug = 1
		self.spinner = spinner
		self._running_root = trees["/"]["root_config"]
		self._opts_no_restart = Scheduler._opts_no_restart
		self.pkgsettings = {}
		# Maps slot atom to package for each Package added to the graph.
		self._slot_pkg_map = {}
		# Maps nodes to the reasons they were selected for reinstallation.
		self._reinstall_nodes = {}
		self.mydbapi = {}
		self.trees = {}
		self._trees_orig = trees
		self.roots = {}
		# Contains a filtered view of preferred packages that are selected
		# from available repositories.
		self._filtered_trees = {}
		# Contains installed packages and new packages that have been added
		# to the graph.
		self._graph_trees = {}
		# All Package instances
		self._pkg_cache = {}
		for myroot in trees:
			self.trees[myroot] = {}
			# Create a RootConfig instance that references
			# the FakeVartree instead of the real one.
			self.roots[myroot] = RootConfig(
				trees[myroot]["vartree"].settings,
				self.trees[myroot],
				trees[myroot]["root_config"].setconfig)
			for tree in ("porttree", "bintree"):
				self.trees[myroot][tree] = trees[myroot][tree]
			self.trees[myroot]["vartree"] = \
				FakeVartree(trees[myroot]["root_config"],
					pkg_cache=self._pkg_cache)
			self.pkgsettings[myroot] = portage.config(
				clone=self.trees[myroot]["vartree"].settings)
			self._slot_pkg_map[myroot] = {}
			vardb = self.trees[myroot]["vartree"].dbapi
			preload_installed_pkgs = "--nodeps" not in self.myopts and \
				"--buildpkgonly" not in self.myopts
			# This fakedbapi instance will model the state that the vdb will
			# have after new packages have been installed.
			fakedb = PackageVirtualDbapi(vardb.settings)
			if preload_installed_pkgs:
				for pkg in vardb:
					self.spinner.update()
					# This triggers metadata updates via FakeVartree.
					vardb.aux_get(pkg.cpv, [])
					fakedb.cpv_inject(pkg)

			# Now that the vardb state is cached in our FakeVartree,
			# we won't be needing the real vartree cache for awhile.
			# To make some room on the heap, clear the vardbapi
			# caches.
			trees[myroot]["vartree"].dbapi._clear_cache()
			gc.collect()

			self.mydbapi[myroot] = fakedb
			def graph_tree():
				pass
			graph_tree.dbapi = fakedb
			self._graph_trees[myroot] = {}
			self._filtered_trees[myroot] = {}
			# Substitute the graph tree for the vartree in dep_check() since we
			# want atom selections to be consistent with package selections
			# have already been made.
			self._graph_trees[myroot]["porttree"]   = graph_tree
			self._graph_trees[myroot]["vartree"]    = graph_tree
			def filtered_tree():
				pass
			filtered_tree.dbapi = self._dep_check_composite_db(self, myroot)
			self._filtered_trees[myroot]["porttree"] = filtered_tree

			# Passing in graph_tree as the vartree here could lead to better
			# atom selections in some cases by causing atoms for packages that
			# have been added to the graph to be preferred over other choices.
			# However, it can trigger atom selections that result in
			# unresolvable direct circular dependencies. For example, this
			# happens with gwydion-dylan which depends on either itself or
			# gwydion-dylan-bin. In case gwydion-dylan is not yet installed,
			# gwydion-dylan-bin needs to be selected in order to avoid a
			# an unresolvable direct circular dependency.
			#
			# To solve the problem described above, pass in "graph_db" so that
			# packages that have been added to the graph are distinguishable
			# from other available packages and installed packages. Also, pass
			# the parent package into self._select_atoms() calls so that
			# unresolvable direct circular dependencies can be detected and
			# avoided when possible.
			self._filtered_trees[myroot]["graph_db"] = graph_tree.dbapi
			self._filtered_trees[myroot]["vartree"] = self.trees[myroot]["vartree"]

			dbs = []
			portdb = self.trees[myroot]["porttree"].dbapi
			bindb  = self.trees[myroot]["bintree"].dbapi
			vardb  = self.trees[myroot]["vartree"].dbapi
			#               (db, pkg_type, built, installed, db_keys)
			if "--usepkgonly" not in self.myopts:
				db_keys = list(portdb._aux_cache_keys)
				dbs.append((portdb, "ebuild", False, False, db_keys))
			if "--usepkg" in self.myopts:
				db_keys = list(bindb._aux_cache_keys)
				dbs.append((bindb,  "binary", True, False, db_keys))
			db_keys = list(trees[myroot]["vartree"].dbapi._aux_cache_keys)
			dbs.append((vardb, "installed", True, True, db_keys))
			self._filtered_trees[myroot]["dbs"] = dbs
			if "--usepkg" in self.myopts:
				self.trees[myroot]["bintree"].populate(
					"--getbinpkg" in self.myopts,
					"--getbinpkgonly" in self.myopts)
		del trees

		self.digraph=portage.digraph()
		# contains all sets added to the graph
		self._sets = {}
		# contains atoms given as arguments
		self._sets["args"] = InternalPackageSet()
		# contains all atoms from all sets added to the graph, including
		# atoms given as arguments
		self._set_atoms = InternalPackageSet()
		self._atom_arg_map = {}
		# contains all nodes pulled in by self._set_atoms
		self._set_nodes = set()
		# Contains only Blocker -> Uninstall edges
		self._blocker_uninstalls = digraph()
		# Contains only Package -> Blocker edges
		self._blocker_parents = digraph()
		# Contains only irrelevant Package -> Blocker edges
		self._irrelevant_blockers = digraph()
		# Contains only unsolvable Package -> Blocker edges
		self._unsolvable_blockers = digraph()
		# Contains all Blocker -> Blocked Package edges
		self._blocked_pkgs = digraph()
		# Contains world packages that have been protected from
		# uninstallation but may not have been added to the graph
		# if the graph is not complete yet.
		self._blocked_world_pkgs = {}
		self._slot_collision_info = {}
		# Slot collision nodes are not allowed to block other packages since
		# blocker validation is only able to account for one package per slot.
		self._slot_collision_nodes = set()
		self._parent_atoms = {}
		self._slot_conflict_parent_atoms = set()
		self._serialized_tasks_cache = None
		self._scheduler_graph = None
		self._displayed_list = None
		self._pprovided_args = []
		self._missing_args = []
		self._masked_installed = set()
		self._unsatisfied_deps_for_display = []
		self._unsatisfied_blockers_for_display = None
		self._circular_deps_for_display = None
		self._dep_stack = []
		self._unsatisfied_deps = []
		self._initially_unsatisfied_deps = []
		self._ignored_deps = []
		self._required_set_names = set(["system", "world"])
		self._select_atoms = self._select_atoms_highest_available
		self._select_package = self._select_pkg_highest_available
		self._highest_pkg_cache = {}

	def _show_slot_collision_notice(self):
		"""Show an informational message advising the user to mask one of the
		the packages. In some cases it may be possible to resolve this
		automatically, but support for backtracking (removal nodes that have
		already been selected) will be required in order to handle all possible
		cases.
		"""

		if not self._slot_collision_info:
			return

		self._show_merge_list()

		msg = []
		msg.append("\n!!! Multiple package instances within a single " + \
			"package slot have been pulled\n")
		msg.append("!!! into the dependency graph, resulting" + \
			" in a slot conflict:\n\n")
		indent = "  "
		# Max number of parents shown, to avoid flooding the display.
		max_parents = 3
		explanation_columns = 70
		explanations = 0
		for (slot_atom, root), slot_nodes \
			in self._slot_collision_info.iteritems():
			msg.append(str(slot_atom))
			msg.append("\n\n")

			for node in slot_nodes:
				msg.append(indent)
				msg.append(str(node))
				parent_atoms = self._parent_atoms.get(node)
				if parent_atoms:
					pruned_list = set()
					# Prefer conflict atoms over others.
					for parent_atom in parent_atoms:
						if len(pruned_list) >= max_parents:
							break
						if parent_atom in self._slot_conflict_parent_atoms:
							pruned_list.add(parent_atom)

					# If this package was pulled in by conflict atoms then
					# show those alone since those are the most interesting.
					if not pruned_list:
						# When generating the pruned list, prefer instances
						# of DependencyArg over instances of Package.
						for parent_atom in parent_atoms:
							if len(pruned_list) >= max_parents:
								break
							parent, atom = parent_atom
							if isinstance(parent, DependencyArg):
								pruned_list.add(parent_atom)
						# Prefer Packages instances that themselves have been
						# pulled into collision slots.
						for parent_atom in parent_atoms:
							if len(pruned_list) >= max_parents:
								break
							parent, atom = parent_atom
							if isinstance(parent, Package) and \
								(parent.slot_atom, parent.root) \
								in self._slot_collision_info:
								pruned_list.add(parent_atom)
						for parent_atom in parent_atoms:
							if len(pruned_list) >= max_parents:
								break
							pruned_list.add(parent_atom)
					omitted_parents = len(parent_atoms) - len(pruned_list)
					parent_atoms = pruned_list
					msg.append(" pulled in by\n")
					for parent_atom in parent_atoms:
						parent, atom = parent_atom
						msg.append(2*indent)
						if isinstance(parent,
							(PackageArg, AtomArg)):
							# For PackageArg and AtomArg types, it's
							# redundant to display the atom attribute.
							msg.append(str(parent))
						else:
							# Display the specific atom from SetArg or
							# Package types.
							msg.append("%s required by %s" % (atom, parent))
						msg.append("\n")
					if omitted_parents:
						msg.append(2*indent)
						msg.append("(and %d more)\n" % omitted_parents)
				else:
					msg.append(" (no parents)\n")
				msg.append("\n")
			explanation = self._slot_conflict_explanation(slot_nodes)
			if explanation:
				explanations += 1
				msg.append(indent + "Explanation:\n\n")
				for line in textwrap.wrap(explanation, explanation_columns):
					msg.append(2*indent + line + "\n")
				msg.append("\n")
		msg.append("\n")
		sys.stderr.write("".join(msg))
		sys.stderr.flush()

		explanations_for_all = explanations == len(self._slot_collision_info)

		if explanations_for_all or "--quiet" in self.myopts:
			return

		msg = []
		msg.append("It may be possible to solve this problem ")
		msg.append("by using package.mask to prevent one of ")
		msg.append("those packages from being selected. ")
		msg.append("However, it is also possible that conflicting ")
		msg.append("dependencies exist such that they are impossible to ")
		msg.append("satisfy simultaneously.  If such a conflict exists in ")
		msg.append("the dependencies of two different packages, then those ")
		msg.append("packages can not be installed simultaneously.")

		from formatter import AbstractFormatter, DumbWriter
		f = AbstractFormatter(DumbWriter(sys.stderr, maxcol=72))
		for x in msg:
			f.add_flowing_data(x)
		f.end_paragraph(1)

		msg = []
		msg.append("For more information, see MASKED PACKAGES ")
		msg.append("section in the emerge man page or refer ")
		msg.append("to the Gentoo Handbook.")
		for x in msg:
			f.add_flowing_data(x)
		f.end_paragraph(1)
		f.writer.flush()

	def _slot_conflict_explanation(self, slot_nodes):
		"""
		When a slot conflict occurs due to USE deps, there are a few
		different cases to consider:

		1) New USE are correctly set but --newuse wasn't requested so an
		   installed package with incorrect USE happened to get pulled
		   into graph before the new one.

		2) New USE are incorrectly set but an installed package has correct
		   USE so it got pulled into the graph, and a new instance also got
		   pulled in due to --newuse or an upgrade.

		3) Multiple USE deps exist that can't be satisfied simultaneously,
		   and multiple package instances got pulled into the same slot to
		   satisfy the conflicting deps.

		Currently, explanations and suggested courses of action are generated
		for cases 1 and 2. Case 3 is too complex to give a useful suggestion.
		"""

		if len(slot_nodes) != 2:
			# Suggestions are only implemented for
			# conflicts between two packages.
			return None

		all_conflict_atoms = self._slot_conflict_parent_atoms
		matched_node = None
		matched_atoms = None
		unmatched_node = None
		for node in slot_nodes:
			parent_atoms = self._parent_atoms.get(node)
			if not parent_atoms:
				# Normally, there are always parent atoms. If there are
				# none then something unexpected is happening and there's
				# currently no suggestion for this case.
				return None
			conflict_atoms = all_conflict_atoms.intersection(parent_atoms)
			for parent_atom in conflict_atoms:
				parent, atom = parent_atom
				if not atom.use:
					# Suggestions are currently only implemented for cases
					# in which all conflict atoms have USE deps.
					return None
			if conflict_atoms:
				if matched_node is not None:
					# If conflict atoms match multiple nodes
					# then there's no suggestion.
					return None
				matched_node = node
				matched_atoms = conflict_atoms
			else:
				if unmatched_node is not None:
					# Neither node is matched by conflict atoms, and
					# there is no suggestion for this case.
					return None
				unmatched_node = node

		if matched_node is None or unmatched_node is None:
			# This shouldn't happen.
			return None

		if unmatched_node.installed and not matched_node.installed and \
			unmatched_node.cpv == matched_node.cpv:
			# If the conflicting packages are the same version then
			# --newuse should be all that's needed. If they are different
			# versions then there's some other problem.
			return "New USE are correctly set, but --newuse wasn't" + \
				" requested, so an installed package with incorrect USE " + \
				"happened to get pulled into the dependency graph. " + \
				"In order to solve " + \
				"this, either specify the --newuse option or explicitly " + \
				" reinstall '%s'." % matched_node.slot_atom

		if matched_node.installed and not unmatched_node.installed:
			atoms = sorted(set(atom for parent, atom in matched_atoms))
			explanation = ("New USE for '%s' are incorrectly set. " + \
				"In order to solve this, adjust USE to satisfy '%s'") % \
				(matched_node.slot_atom, atoms[0])
			if len(atoms) > 1:
				for atom in atoms[1:-1]:
					explanation += ", '%s'" % (atom,)
				if len(atoms) > 2:
					explanation += ","
				explanation += " and '%s'" % (atoms[-1],)
			explanation += "."
			return explanation

		return None

	def _process_slot_conflicts(self):
		"""
		Process slot conflict data to identify specific atoms which
		lead to conflict. These atoms only match a subset of the
		packages that have been pulled into a given slot.
		"""
		for (slot_atom, root), slot_nodes \
			in self._slot_collision_info.iteritems():

			all_parent_atoms = set()
			for pkg in slot_nodes:
				parent_atoms = self._parent_atoms.get(pkg)
				if not parent_atoms:
					continue
				all_parent_atoms.update(parent_atoms)

			for pkg in slot_nodes:
				parent_atoms = self._parent_atoms.get(pkg)
				if parent_atoms is None:
					parent_atoms = set()
					self._parent_atoms[pkg] = parent_atoms
				for parent_atom in all_parent_atoms:
					if parent_atom in parent_atoms:
						continue
					# Use package set for matching since it will match via
					# PROVIDE when necessary, while match_from_list does not.
					parent, atom = parent_atom
					atom_set = InternalPackageSet(
						initial_atoms=(atom,))
					if atom_set.findAtomForPackage(pkg):
						parent_atoms.add(parent_atom)
					else:
						self._slot_conflict_parent_atoms.add(parent_atom)

	def _reinstall_for_flags(self, forced_flags,
		orig_use, orig_iuse, cur_use, cur_iuse):
		"""Return a set of flags that trigger reinstallation, or None if there
		are no such flags."""
		if "--newuse" in self.myopts:
			flags = set(orig_iuse.symmetric_difference(
				cur_iuse).difference(forced_flags))
			flags.update(orig_iuse.intersection(orig_use).symmetric_difference(
				cur_iuse.intersection(cur_use)))
			if flags:
				return flags
		elif "changed-use" == self.myopts.get("--reinstall"):
			flags = orig_iuse.intersection(orig_use).symmetric_difference(
				cur_iuse.intersection(cur_use))
			if flags:
				return flags
		return None

	def _create_graph(self, allow_unsatisfied=False):
		dep_stack = self._dep_stack
		while dep_stack:
			self.spinner.update()
			dep = dep_stack.pop()
			if isinstance(dep, Package):
				if not self._add_pkg_deps(dep,
					allow_unsatisfied=allow_unsatisfied):
					return 0
				continue
			if not self._add_dep(dep, allow_unsatisfied=allow_unsatisfied):
				return 0
		return 1

	def _add_dep(self, dep, allow_unsatisfied=False):
		debug = "--debug" in self.myopts
		buildpkgonly = "--buildpkgonly" in self.myopts
		nodeps = "--nodeps" in self.myopts
		empty = "empty" in self.myparams
		deep = "deep" in self.myparams
		update = "--update" in self.myopts and dep.depth <= 1
		if dep.blocker:
			if not buildpkgonly and \
				not nodeps and \
				dep.parent not in self._slot_collision_nodes:
				if dep.parent.onlydeps:
					# It's safe to ignore blockers if the
					# parent is an --onlydeps node.
					return 1
				# The blocker applies to the root where
				# the parent is or will be installed.
				blocker = Blocker(atom=dep.atom,
					eapi=dep.parent.metadata["EAPI"],
					root=dep.parent.root)
				self._blocker_parents.add(blocker, dep.parent)
			return 1
		dep_pkg, existing_node = self._select_package(dep.root, dep.atom,
			onlydeps=dep.onlydeps)
		if not dep_pkg:
			if dep.priority.optional:
				# This could be an unecessary build-time dep
				# pulled in by --with-bdeps=y.
				return 1
			if allow_unsatisfied:
				self._unsatisfied_deps.append(dep)
				return 1
			self._unsatisfied_deps_for_display.append(
				((dep.root, dep.atom), {"myparent":dep.parent}))
			return 0
		# In some cases, dep_check will return deps that shouldn't
		# be proccessed any further, so they are identified and
		# discarded here. Try to discard as few as possible since
		# discarded dependencies reduce the amount of information
		# available for optimization of merge order.
		if dep.priority.satisfied and \
			not dep_pkg.installed and \
			not (existing_node or empty or deep or update):
			myarg = None
			if dep.root == self.target_root:
				try:
					myarg = self._iter_atoms_for_pkg(dep_pkg).next()
				except StopIteration:
					pass
				except portage.exception.InvalidDependString:
					if not dep_pkg.installed:
						# This shouldn't happen since the package
						# should have been masked.
						raise
			if not myarg:
				self._ignored_deps.append(dep)
				return 1

		if not self._add_pkg(dep_pkg, dep):
			return 0
		return 1

	def _add_pkg(self, pkg, dep):
		myparent = None
		priority = None
		depth = 0
		if dep is None:
			dep = Dependency()
		else:
			myparent = dep.parent
			priority = dep.priority
			depth = dep.depth
		if priority is None:
			priority = DepPriority()
		"""
		Fills the digraph with nodes comprised of packages to merge.
		mybigkey is the package spec of the package to merge.
		myparent is the package depending on mybigkey ( or None )
		addme = Should we add this package to the digraph or are we just looking at it's deps?
			Think --onlydeps, we need to ignore packages in that case.
		#stuff to add:
		#SLOT-aware emerge
		#IUSE-aware emerge -> USE DEP aware depgraph
		#"no downgrade" emerge
		"""
		# Ensure that the dependencies of the same package
		# are never processed more than once.
		previously_added = pkg in self.digraph

		# select the correct /var database that we'll be checking against
		vardbapi = self.trees[pkg.root]["vartree"].dbapi
		pkgsettings = self.pkgsettings[pkg.root]

		arg_atoms = None
		if True:
			try:
				arg_atoms = list(self._iter_atoms_for_pkg(pkg))
			except portage.exception.InvalidDependString, e:
				if not pkg.installed:
					show_invalid_depstring_notice(
						pkg, pkg.metadata["PROVIDE"], str(e))
					return 0
				del e

		if not pkg.onlydeps:
			if not pkg.installed and \
				"empty" not in self.myparams and \
				vardbapi.match(pkg.slot_atom):
				# Increase the priority of dependencies on packages that
				# are being rebuilt. This optimizes merge order so that
				# dependencies are rebuilt/updated as soon as possible,
				# which is needed especially when emerge is called by
				# revdep-rebuild since dependencies may be affected by ABI
				# breakage that has rendered them useless. Don't adjust
				# priority here when in "empty" mode since all packages
				# are being merged in that case.
				priority.rebuild = True

			existing_node = self._slot_pkg_map[pkg.root].get(pkg.slot_atom)
			slot_collision = False
			if existing_node:
				existing_node_matches = pkg.cpv == existing_node.cpv
				if existing_node_matches and \
					pkg != existing_node and \
					dep.atom is not None:
					# Use package set for matching since it will match via
					# PROVIDE when necessary, while match_from_list does not.
					atom_set = InternalPackageSet(initial_atoms=[dep.atom])
					if not atom_set.findAtomForPackage(existing_node):
						existing_node_matches = False
				if existing_node_matches:
					# The existing node can be reused.
					if arg_atoms:
						for parent_atom in arg_atoms:
							parent, atom = parent_atom
							self.digraph.add(existing_node, parent,
								priority=priority)
							self._add_parent_atom(existing_node, parent_atom)
					# If a direct circular dependency is not an unsatisfied
					# buildtime dependency then drop it here since otherwise
					# it can skew the merge order calculation in an unwanted
					# way.
					if existing_node != myparent or \
						(priority.buildtime and not priority.satisfied):
						self.digraph.addnode(existing_node, myparent,
							priority=priority)
						if dep.atom is not None and dep.parent is not None:
							self._add_parent_atom(existing_node,
								(dep.parent, dep.atom))
					return 1
				else:

					# A slot collision has occurred.  Sometimes this coincides
					# with unresolvable blockers, so the slot collision will be
					# shown later if there are no unresolvable blockers.
					self._add_slot_conflict(pkg)
					slot_collision = True

			if slot_collision:
				# Now add this node to the graph so that self.display()
				# can show use flags and --tree portage.output.  This node is
				# only being partially added to the graph.  It must not be
				# allowed to interfere with the other nodes that have been
				# added.  Do not overwrite data for existing nodes in
				# self.mydbapi since that data will be used for blocker
				# validation.
				# Even though the graph is now invalid, continue to process
				# dependencies so that things like --fetchonly can still
				# function despite collisions.
				pass
			elif not previously_added:
				self._slot_pkg_map[pkg.root][pkg.slot_atom] = pkg
				self.mydbapi[pkg.root].cpv_inject(pkg)
				self._filtered_trees[pkg.root]["porttree"].dbapi._clear_cache()

			if not pkg.installed:
				# Allow this package to satisfy old-style virtuals in case it
				# doesn't already. Any pre-existing providers will be preferred
				# over this one.
				try:
					pkgsettings.setinst(pkg.cpv, pkg.metadata)
					# For consistency, also update the global virtuals.
					settings = self.roots[pkg.root].settings
					settings.unlock()
					settings.setinst(pkg.cpv, pkg.metadata)
					settings.lock()
				except portage.exception.InvalidDependString, e:
					show_invalid_depstring_notice(
						pkg, pkg.metadata["PROVIDE"], str(e))
					del e
					return 0

		if arg_atoms:
			self._set_nodes.add(pkg)

		# Do this even when addme is False (--onlydeps) so that the
		# parent/child relationship is always known in case
		# self._show_slot_collision_notice() needs to be called later.
		self.digraph.add(pkg, myparent, priority=priority)
		if dep.atom is not None and dep.parent is not None:
			self._add_parent_atom(pkg, (dep.parent, dep.atom))

		if arg_atoms:
			for parent_atom in arg_atoms:
				parent, atom = parent_atom
				self.digraph.add(pkg, parent, priority=priority)
				self._add_parent_atom(pkg, parent_atom)

		""" This section determines whether we go deeper into dependencies or not.
		    We want to go deeper on a few occasions:
		    Installing package A, we need to make sure package A's deps are met.
		    emerge --deep <pkgspec>; we need to recursively check dependencies of pkgspec
		    If we are in --nodeps (no recursion) mode, we obviously only check 1 level of dependencies.
		"""
		dep_stack = self._dep_stack
		if "recurse" not in self.myparams:
			return 1
		elif pkg.installed and \
			"deep" not in self.myparams:
			dep_stack = self._ignored_deps

		self.spinner.update()

		if arg_atoms:
			depth = 0
		pkg.depth = depth
		if not previously_added:
			dep_stack.append(pkg)
		return 1

	def _add_parent_atom(self, pkg, parent_atom):
		parent_atoms = self._parent_atoms.get(pkg)
		if parent_atoms is None:
			parent_atoms = set()
			self._parent_atoms[pkg] = parent_atoms
		parent_atoms.add(parent_atom)

	def _add_slot_conflict(self, pkg):
		self._slot_collision_nodes.add(pkg)
		slot_key = (pkg.slot_atom, pkg.root)
		slot_nodes = self._slot_collision_info.get(slot_key)
		if slot_nodes is None:
			slot_nodes = set()
			slot_nodes.add(self._slot_pkg_map[pkg.root][pkg.slot_atom])
			self._slot_collision_info[slot_key] = slot_nodes
		slot_nodes.add(pkg)

	def _add_pkg_deps(self, pkg, allow_unsatisfied=False):

		mytype = pkg.type_name
		myroot = pkg.root
		mykey = pkg.cpv
		metadata = pkg.metadata
		myuse = pkg.use.enabled
		jbigkey = pkg
		depth = pkg.depth + 1
		removal_action = "remove" in self.myparams

		edepend={}
		depkeys = ["DEPEND","RDEPEND","PDEPEND"]
		for k in depkeys:
			edepend[k] = metadata[k]

		if not pkg.built and \
			"--buildpkgonly" in self.myopts and \
			"deep" not in self.myparams and \
			"empty" not in self.myparams:
			edepend["RDEPEND"] = ""
			edepend["PDEPEND"] = ""
		bdeps_optional = False

		if pkg.built and not removal_action:
			if self.myopts.get("--with-bdeps", "n") == "y":
				# Pull in build time deps as requested, but marked them as
				# "optional" since they are not strictly required. This allows
				# more freedom in the merge order calculation for solving
				# circular dependencies. Don't convert to PDEPEND since that
				# could make --with-bdeps=y less effective if it is used to
				# adjust merge order to prevent built_with_use() calls from
				# failing.
				bdeps_optional = True
			else:
				# built packages do not have build time dependencies.
				edepend["DEPEND"] = ""

		if removal_action and self.myopts.get("--with-bdeps", "y") == "n":
			edepend["DEPEND"] = ""

		deps = (
			("/", edepend["DEPEND"],
				self._priority(buildtime=(not bdeps_optional),
				optional=bdeps_optional)),
			(myroot, edepend["RDEPEND"], self._priority(runtime=True)),
			(myroot, edepend["PDEPEND"], self._priority(runtime_post=True))
		)

		debug = "--debug" in self.myopts
		strict = mytype != "installed"
		try:
			for dep_root, dep_string, dep_priority in deps:
				if not dep_string:
					continue
				if debug:
					print
					print "Parent:   ", jbigkey
					print "Depstring:", dep_string
					print "Priority:", dep_priority
				vardb = self.roots[dep_root].trees["vartree"].dbapi
				try:
					selected_atoms = self._select_atoms(dep_root,
						dep_string, myuse=myuse, parent=pkg, strict=strict,
						priority=dep_priority)
				except portage.exception.InvalidDependString, e:
					show_invalid_depstring_notice(jbigkey, dep_string, str(e))
					return 0
				if debug:
					print "Candidates:", selected_atoms

				for atom in selected_atoms:
					try:

						atom = portage.dep.Atom(atom)

						mypriority = dep_priority.copy()
						if not atom.blocker and vardb.match(atom):
							mypriority.satisfied = True

						if not self._add_dep(Dependency(atom=atom,
							blocker=atom.blocker, depth=depth, parent=pkg,
							priority=mypriority, root=dep_root),
							allow_unsatisfied=allow_unsatisfied):
							return 0

					except portage.exception.InvalidAtom, e:
						show_invalid_depstring_notice(
							pkg, dep_string, str(e))
						del e
						if not pkg.installed:
							return 0

				if debug:
					print "Exiting...", jbigkey
		except portage.exception.AmbiguousPackageName, e:
			pkgs = e.args[0]
			portage.writemsg("\n\n!!! An atom in the dependencies " + \
				"is not fully-qualified. Multiple matches:\n\n", noiselevel=-1)
			for cpv in pkgs:
				portage.writemsg("    %s\n" % cpv, noiselevel=-1)
			portage.writemsg("\n", noiselevel=-1)
			if mytype == "binary":
				portage.writemsg(
					"!!! This binary package cannot be installed: '%s'\n" % \
					mykey, noiselevel=-1)
			elif mytype == "ebuild":
				portdb = self.roots[myroot].trees["porttree"].dbapi
				myebuild, mylocation = portdb.findname2(mykey)
				portage.writemsg("!!! This ebuild cannot be installed: " + \
					"'%s'\n" % myebuild, noiselevel=-1)
			portage.writemsg("!!! Please notify the package maintainer " + \
				"that atoms must be fully-qualified.\n", noiselevel=-1)
			return 0
		return 1

	def _priority(self, **kwargs):
		if "remove" in self.myparams:
			priority_constructor = UnmergeDepPriority
		else:
			priority_constructor = DepPriority
		return priority_constructor(**kwargs)

	def _dep_expand(self, root_config, atom_without_category):
		"""
		@param root_config: a root config instance
		@type root_config: RootConfig
		@param atom_without_category: an atom without a category component
		@type atom_without_category: String
		@rtype: list
		@returns: a list of atoms containing categories (possibly empty)
		"""
		null_cp = portage.dep_getkey(insert_category_into_atom(
			atom_without_category, "null"))
		cat, atom_pn = portage.catsplit(null_cp)

		dbs = self._filtered_trees[root_config.root]["dbs"]
		categories = set()
		for db, pkg_type, built, installed, db_keys in dbs:
			for cat in db.categories:
				if db.cp_list("%s/%s" % (cat, atom_pn)):
					categories.add(cat)

		deps = []
		for cat in categories:
			deps.append(insert_category_into_atom(
				atom_without_category, cat))
		return deps

	def _have_new_virt(self, root, atom_cp):
		ret = False
		for db, pkg_type, built, installed, db_keys in \
			self._filtered_trees[root]["dbs"]:
			if db.cp_list(atom_cp):
				ret = True
				break
		return ret

	def _iter_atoms_for_pkg(self, pkg):
		# TODO: add multiple $ROOT support
		if pkg.root != self.target_root:
			return
		atom_arg_map = self._atom_arg_map
		root_config = self.roots[pkg.root]
		for atom in self._set_atoms.iterAtomsForPackage(pkg):
			atom_cp = portage.dep_getkey(atom)
			if atom_cp != pkg.cp and \
				self._have_new_virt(pkg.root, atom_cp):
				continue
			visible_pkgs = root_config.visible_pkgs.match_pkgs(atom)
			visible_pkgs.reverse() # descending order
			higher_slot = None
			for visible_pkg in visible_pkgs:
				if visible_pkg.cp != atom_cp:
					continue
				if pkg >= visible_pkg:
					# This is descending order, and we're not
					# interested in any versions <= pkg given.
					break
				if pkg.slot_atom != visible_pkg.slot_atom:
					higher_slot = visible_pkg
					break
			if higher_slot is not None:
				continue
			for arg in atom_arg_map[(atom, pkg.root)]:
				if isinstance(arg, PackageArg) and \
					arg.package != pkg:
					continue
				yield arg, atom

	def select_files(self, myfiles):
		"""Given a list of .tbz2s, .ebuilds sets, and deps, create the
		appropriate depgraph and return a favorite list."""
		debug = "--debug" in self.myopts
		root_config = self.roots[self.target_root]
		sets = root_config.sets
		getSetAtoms = root_config.setconfig.getSetAtoms
		myfavorites=[]
		myroot = self.target_root
		dbs = self._filtered_trees[myroot]["dbs"]
		vardb = self.trees[myroot]["vartree"].dbapi
		real_vardb = self._trees_orig[myroot]["vartree"].dbapi
		portdb = self.trees[myroot]["porttree"].dbapi
		bindb = self.trees[myroot]["bintree"].dbapi
		pkgsettings = self.pkgsettings[myroot]
		args = []
		onlydeps = "--onlydeps" in self.myopts
		lookup_owners = []
		for x in myfiles:
			ext = os.path.splitext(x)[1]
			if ext==".tbz2":
				if not os.path.exists(x):
					if os.path.exists(
						os.path.join(pkgsettings["PKGDIR"], "All", x)):
						x = os.path.join(pkgsettings["PKGDIR"], "All", x)
					elif os.path.exists(
						os.path.join(pkgsettings["PKGDIR"], x)):
						x = os.path.join(pkgsettings["PKGDIR"], x)
					else:
						print "\n\n!!! Binary package '"+str(x)+"' does not exist."
						print "!!! Please ensure the tbz2 exists as specified.\n"
						return 0, myfavorites
				mytbz2=portage.xpak.tbz2(x)
				mykey=mytbz2.getelements("CATEGORY")[0]+"/"+os.path.splitext(os.path.basename(x))[0]
				if os.path.realpath(x) != \
					os.path.realpath(self.trees[myroot]["bintree"].getname(mykey)):
					print colorize("BAD", "\n*** You need to adjust PKGDIR to emerge this package.\n")
					return 0, myfavorites
				db_keys = list(bindb._aux_cache_keys)
				metadata = izip(db_keys, bindb.aux_get(mykey, db_keys))
				pkg = Package(type_name="binary", root_config=root_config,
					cpv=mykey, built=True, metadata=metadata,
					onlydeps=onlydeps)
				self._pkg_cache[pkg] = pkg
				args.append(PackageArg(arg=x, package=pkg,
					root_config=root_config))
			elif ext==".ebuild":
				ebuild_path = portage.util.normalize_path(os.path.abspath(x))
				pkgdir = os.path.dirname(ebuild_path)
				tree_root = os.path.dirname(os.path.dirname(pkgdir))
				cp = pkgdir[len(tree_root)+1:]
				e = portage.exception.PackageNotFound(
					("%s is not in a valid portage tree " + \
					"hierarchy or does not exist") % x)
				if not portage.isvalidatom(cp):
					raise e
				cat = portage.catsplit(cp)[0]
				mykey = cat + "/" + os.path.basename(ebuild_path[:-7])
				if not portage.isvalidatom("="+mykey):
					raise e
				ebuild_path = portdb.findname(mykey)
				if ebuild_path:
					if ebuild_path != os.path.join(os.path.realpath(tree_root),
						cp, os.path.basename(ebuild_path)):
						print colorize("BAD", "\n*** You need to adjust PORTDIR or PORTDIR_OVERLAY to emerge this package.\n")
						return 0, myfavorites
					if mykey not in portdb.xmatch(
						"match-visible", portage.dep_getkey(mykey)):
						print colorize("BAD", "\n*** You are emerging a masked package. It is MUCH better to use")
						print colorize("BAD", "*** /etc/portage/package.* to accomplish this. See portage(5) man")
						print colorize("BAD", "*** page for details.")
						countdown(int(self.settings["EMERGE_WARNING_DELAY"]),
							"Continuing...")
				else:
					raise portage.exception.PackageNotFound(
						"%s is not in a valid portage tree hierarchy or does not exist" % x)
				db_keys = list(portdb._aux_cache_keys)
				metadata = izip(db_keys, portdb.aux_get(mykey, db_keys))
				pkg = Package(type_name="ebuild", root_config=root_config,
					cpv=mykey, metadata=metadata, onlydeps=onlydeps)
				pkgsettings.setcpv(pkg)
				pkg.metadata["USE"] = pkgsettings["PORTAGE_USE"]
				pkg.metadata['CHOST'] = pkgsettings.get('CHOST', '')
				self._pkg_cache[pkg] = pkg
				args.append(PackageArg(arg=x, package=pkg,
					root_config=root_config))
			elif x.startswith(os.path.sep):
				if not x.startswith(myroot):
					portage.writemsg(("\n\n!!! '%s' does not start with" + \
						" $ROOT.\n") % x, noiselevel=-1)
					return 0, []
				# Queue these up since it's most efficient to handle
				# multiple files in a single iter_owners() call.
				lookup_owners.append(x)
			else:
				if x in ("system", "world"):
					x = SETPREFIX + x
				if x.startswith(SETPREFIX):
					s = x[len(SETPREFIX):]
					if s not in sets:
						raise portage.exception.PackageSetNotFound(s)
					if s in self._sets:
						continue
					# Recursively expand sets so that containment tests in
					# self._get_parent_sets() properly match atoms in nested
					# sets (like if world contains system).
					expanded_set = InternalPackageSet(
						initial_atoms=getSetAtoms(s))
					self._sets[s] = expanded_set
					args.append(SetArg(arg=x, set=expanded_set,
						root_config=root_config))
					continue
				if not is_valid_package_atom(x):
					portage.writemsg("\n\n!!! '%s' is not a valid package atom.\n" % x,
						noiselevel=-1)
					portage.writemsg("!!! Please check ebuild(5) for full details.\n")
					portage.writemsg("!!! (Did you specify a version but forget to prefix with '='?)\n")
					return (0,[])
				# Don't expand categories or old-style virtuals here unless
				# necessary. Expansion of old-style virtuals here causes at
				# least the following problems:
				#   1) It's more difficult to determine which set(s) an atom
				#      came from, if any.
				#   2) It takes away freedom from the resolver to choose other
				#      possible expansions when necessary.
				if "/" in x:
					args.append(AtomArg(arg=x, atom=x,
						root_config=root_config))
					continue
				expanded_atoms = self._dep_expand(root_config, x)
				installed_cp_set = set()
				for atom in expanded_atoms:
					atom_cp = portage.dep_getkey(atom)
					if vardb.cp_list(atom_cp):
						installed_cp_set.add(atom_cp)
				if len(expanded_atoms) > 1 and len(installed_cp_set) == 1:
					installed_cp = iter(installed_cp_set).next()
					expanded_atoms = [atom for atom in expanded_atoms \
						if portage.dep_getkey(atom) == installed_cp]

				if len(expanded_atoms) > 1:
					print
					print
					ambiguous_package_name(x, expanded_atoms, root_config,
						self.spinner, self.myopts)
					return False, myfavorites
				if expanded_atoms:
					atom = expanded_atoms[0]
				else:
					null_atom = insert_category_into_atom(x, "null")
					null_cp = portage.dep_getkey(null_atom)
					cat, atom_pn = portage.catsplit(null_cp)
					virts_p = root_config.settings.get_virts_p().get(atom_pn)
					if virts_p:
						# Allow the depgraph to choose which virtual.
						atom = insert_category_into_atom(x, "virtual")
					else:
						atom = insert_category_into_atom(x, "null")

				args.append(AtomArg(arg=x, atom=atom,
					root_config=root_config))

		if lookup_owners:
			relative_paths = []
			search_for_multiple = False
			if len(lookup_owners) > 1:
				search_for_multiple = True

			for x in lookup_owners:
				if not search_for_multiple and os.path.isdir(x):
					search_for_multiple = True
				relative_paths.append(x[len(myroot):])

			owners = set()
			for pkg, relative_path in \
				real_vardb._owners.iter_owners(relative_paths):
				owners.add(pkg.mycpv)
				if not search_for_multiple:
					break

			if not owners:
				portage.writemsg(("\n\n!!! '%s' is not claimed " + \
					"by any package.\n") % lookup_owners[0], noiselevel=-1)
				return 0, []

			for cpv in owners:
				slot = vardb.aux_get(cpv, ["SLOT"])[0]
				if not slot:
					# portage now masks packages with missing slot, but it's
					# possible that one was installed by an older version
					atom = portage.cpv_getkey(cpv)
				else:
					atom = "%s:%s" % (portage.cpv_getkey(cpv), slot)
				args.append(AtomArg(arg=atom, atom=atom,
					root_config=root_config))

		if "--update" in self.myopts:
			# In some cases, the greedy slots behavior can pull in a slot that
			# the user would want to uninstall due to it being blocked by a
			# newer version in a different slot. Therefore, it's necessary to
			# detect and discard any that should be uninstalled. Each time
			# that arguments are updated, package selections are repeated in
			# order to ensure consistency with the current arguments:
			#
			#  1) Initialize args
			#  2) Select packages and generate initial greedy atoms
			#  3) Update args with greedy atoms
			#  4) Select packages and generate greedy atoms again, while
			#     accounting for any blockers between selected packages
			#  5) Update args with revised greedy atoms

			self._set_args(args)
			greedy_args = []
			for arg in args:
				greedy_args.append(arg)
				if not isinstance(arg, AtomArg):
					continue
				for atom in self._greedy_slots(arg.root_config, arg.atom):
					greedy_args.append(
						AtomArg(arg=arg.arg, atom=atom,
							root_config=arg.root_config))

			self._set_args(greedy_args)
			del greedy_args

			# Revise greedy atoms, accounting for any blockers
			# between selected packages.
			revised_greedy_args = []
			for arg in args:
				revised_greedy_args.append(arg)
				if not isinstance(arg, AtomArg):
					continue
				for atom in self._greedy_slots(arg.root_config, arg.atom,
					blocker_lookahead=True):
					revised_greedy_args.append(
						AtomArg(arg=arg.arg, atom=atom,
							root_config=arg.root_config))
			args = revised_greedy_args
			del revised_greedy_args

		self._set_args(args)

		myfavorites = set(myfavorites)
		for arg in args:
			if isinstance(arg, (AtomArg, PackageArg)):
				myfavorites.add(arg.atom)
			elif isinstance(arg, SetArg):
				myfavorites.add(arg.arg)
		myfavorites = list(myfavorites)

		pprovideddict = pkgsettings.pprovideddict
		if debug:
			portage.writemsg("\n", noiselevel=-1)
		# Order needs to be preserved since a feature of --nodeps
		# is to allow the user to force a specific merge order.
		args.reverse()
		while args:
			arg = args.pop()
			for atom in arg.set:
				self.spinner.update()
				dep = Dependency(atom=atom, onlydeps=onlydeps,
					root=myroot, parent=arg)
				atom_cp = portage.dep_getkey(atom)
				try:
					pprovided = pprovideddict.get(portage.dep_getkey(atom))
					if pprovided and portage.match_from_list(atom, pprovided):
						# A provided package has been specified on the command line.
						self._pprovided_args.append((arg, atom))
						continue
					if isinstance(arg, PackageArg):
						if not self._add_pkg(arg.package, dep) or \
							not self._create_graph():
							sys.stderr.write(("\n\n!!! Problem resolving " + \
								"dependencies for %s\n") % arg.arg)
							return 0, myfavorites
						continue
					if debug:
						portage.writemsg("      Arg: %s\n     Atom: %s\n" % \
							(arg, atom), noiselevel=-1)
					pkg, existing_node = self._select_package(
						myroot, atom, onlydeps=onlydeps)
					if not pkg:
						if not (isinstance(arg, SetArg) and \
							arg.name in ("system", "world")):
							self._unsatisfied_deps_for_display.append(
								((myroot, atom), {}))
							return 0, myfavorites
						self._missing_args.append((arg, atom))
						continue
					if atom_cp != pkg.cp:
						# For old-style virtuals, we need to repeat the
						# package.provided check against the selected package.
						expanded_atom = atom.replace(atom_cp, pkg.cp)
						pprovided = pprovideddict.get(pkg.cp)
						if pprovided and \
							portage.match_from_list(expanded_atom, pprovided):
							# A provided package has been
							# specified on the command line.
							self._pprovided_args.append((arg, atom))
							continue
					if pkg.installed and "selective" not in self.myparams:
						self._unsatisfied_deps_for_display.append(
							((myroot, atom), {}))
						# Previous behavior was to bail out in this case, but
						# since the dep is satisfied by the installed package,
						# it's more friendly to continue building the graph
						# and just show a warning message. Therefore, only bail
						# out here if the atom is not from either the system or
						# world set.
						if not (isinstance(arg, SetArg) and \
							arg.name in ("system", "world")):
							return 0, myfavorites

					# Add the selected package to the graph as soon as possible
					# so that later dep_check() calls can use it as feedback
					# for making more consistent atom selections.
					if not self._add_pkg(pkg, dep):
						if isinstance(arg, SetArg):
							sys.stderr.write(("\n\n!!! Problem resolving " + \
								"dependencies for %s from %s\n") % \
								(atom, arg.arg))
						else:
							sys.stderr.write(("\n\n!!! Problem resolving " + \
								"dependencies for %s\n") % atom)
						return 0, myfavorites

				except portage.exception.MissingSignature, e:
					portage.writemsg("\n\n!!! A missing gpg signature is preventing portage from calculating the\n")
					portage.writemsg("!!! required dependencies. This is a security feature enabled by the admin\n")
					portage.writemsg("!!! to aid in the detection of malicious intent.\n\n")
					portage.writemsg("!!! THIS IS A POSSIBLE INDICATION OF TAMPERED FILES -- CHECK CAREFULLY.\n")
					portage.writemsg("!!! Affected file: %s\n" % (e), noiselevel=-1)
					return 0, myfavorites
				except portage.exception.InvalidSignature, e:
					portage.writemsg("\n\n!!! An invalid gpg signature is preventing portage from calculating the\n")
					portage.writemsg("!!! required dependencies. This is a security feature enabled by the admin\n")
					portage.writemsg("!!! to aid in the detection of malicious intent.\n\n")
					portage.writemsg("!!! THIS IS A POSSIBLE INDICATION OF TAMPERED FILES -- CHECK CAREFULLY.\n")
					portage.writemsg("!!! Affected file: %s\n" % (e), noiselevel=-1)
					return 0, myfavorites
				except SystemExit, e:
					raise # Needed else can't exit
				except Exception, e:
					print >> sys.stderr, "\n\n!!! Problem in '%s' dependencies." % atom
					print >> sys.stderr, "!!!", str(e), getattr(e, "__module__", None)
					raise

		# Now that the root packages have been added to the graph,
		# process the dependencies.
		if not self._create_graph():
			return 0, myfavorites

		missing=0
		if "--usepkgonly" in self.myopts:
			for xs in self.digraph.all_nodes():
				if not isinstance(xs, Package):
					continue
				if len(xs) >= 4 and xs[0] != "binary" and xs[3] == "merge":
					if missing == 0:
						print
					missing += 1
					print "Missing binary for:",xs[2]

		try:
			self.altlist()
		except self._unknown_internal_error:
			return False, myfavorites

		# We're true here unless we are missing binaries.
		return (not missing,myfavorites)

	def _set_args(self, args):
		"""
		Create the "args" package set from atoms and packages given as
		arguments. This method can be called multiple times if necessary.
		The package selection cache is automatically invalidated, since
		arguments influence package selections.
		"""
		args_set = self._sets["args"]
		args_set.clear()
		for arg in args:
			if not isinstance(arg, (AtomArg, PackageArg)):
				continue
			atom = arg.atom
			if atom in args_set:
				continue
			args_set.add(atom)

		self._set_atoms.clear()
		self._set_atoms.update(chain(*self._sets.itervalues()))
		atom_arg_map = self._atom_arg_map
		atom_arg_map.clear()
		for arg in args:
			for atom in arg.set:
				atom_key = (atom, arg.root_config.root)
				refs = atom_arg_map.get(atom_key)
				if refs is None:
					refs = []
					atom_arg_map[atom_key] = refs
					if arg not in refs:
						refs.append(arg)

		# Invalidate the package selection cache, since
		# arguments influence package selections.
		self._highest_pkg_cache.clear()
		for trees in self._filtered_trees.itervalues():
			trees["porttree"].dbapi._clear_cache()

	def _greedy_slots(self, root_config, atom, blocker_lookahead=False):
		"""
		Return a list of slot atoms corresponding to installed slots that
		differ from the slot of the highest visible match. When
		blocker_lookahead is True, slot atoms that would trigger a blocker
		conflict are automatically discarded, potentially allowing automatic
		uninstallation of older slots when appropriate.
		"""
		highest_pkg, in_graph = self._select_package(root_config.root, atom)
		if highest_pkg is None:
			return []
		vardb = root_config.trees["vartree"].dbapi
		slots = set()
		for cpv in vardb.match(atom):
			# don't mix new virtuals with old virtuals
			if portage.cpv_getkey(cpv) == highest_pkg.cp:
				slots.add(vardb.aux_get(cpv, ["SLOT"])[0])

		slots.add(highest_pkg.metadata["SLOT"])
		if len(slots) == 1:
			return []
		greedy_pkgs = []
		slots.remove(highest_pkg.metadata["SLOT"])
		while slots:
			slot = slots.pop()
			slot_atom = portage.dep.Atom("%s:%s" % (highest_pkg.cp, slot))
			pkg, in_graph = self._select_package(root_config.root, slot_atom)
			if pkg is not None and \
				pkg.cp == highest_pkg.cp and pkg < highest_pkg:
				greedy_pkgs.append(pkg)
		if not greedy_pkgs:
			return []
		if not blocker_lookahead:
			return [pkg.slot_atom for pkg in greedy_pkgs]

		blockers = {}
		blocker_dep_keys = ["DEPEND", "PDEPEND", "RDEPEND"]
		for pkg in greedy_pkgs + [highest_pkg]:
			dep_str = " ".join(pkg.metadata[k] for k in blocker_dep_keys)
			try:
				atoms = self._select_atoms(
					pkg.root, dep_str, pkg.use.enabled,
					parent=pkg, strict=True)
			except portage.exception.InvalidDependString:
				continue
			blocker_atoms = (x for x in atoms if x.blocker)
			blockers[pkg] = InternalPackageSet(initial_atoms=blocker_atoms)

		if highest_pkg not in blockers:
			return []

		# filter packages with invalid deps
		greedy_pkgs = [pkg for pkg in greedy_pkgs if pkg in blockers]

		# filter packages that conflict with highest_pkg
		greedy_pkgs = [pkg for pkg in greedy_pkgs if not \
			(blockers[highest_pkg].findAtomForPackage(pkg) or \
			blockers[pkg].findAtomForPackage(highest_pkg))]

		if not greedy_pkgs:
			return []

		# If two packages conflict, discard the lower version.
		discard_pkgs = set()
		greedy_pkgs.sort(reverse=True)
		for i in xrange(len(greedy_pkgs) - 1):
			pkg1 = greedy_pkgs[i]
			if pkg1 in discard_pkgs:
				continue
			for j in xrange(i + 1, len(greedy_pkgs)):
				pkg2 = greedy_pkgs[j]
				if pkg2 in discard_pkgs:
					continue
				if blockers[pkg1].findAtomForPackage(pkg2) or \
					blockers[pkg2].findAtomForPackage(pkg1):
					# pkg1 > pkg2
					discard_pkgs.add(pkg2)

		return [pkg.slot_atom for pkg in greedy_pkgs \
			if pkg not in discard_pkgs]

	def _select_atoms_from_graph(self, *pargs, **kwargs):
		"""
		Prefer atoms matching packages that have already been
		added to the graph or those that are installed and have
		not been scheduled for replacement.
		"""
		kwargs["trees"] = self._graph_trees
		return self._select_atoms_highest_available(*pargs, **kwargs)

	def _select_atoms_highest_available(self, root, depstring,
		myuse=None, parent=None, strict=True, trees=None, priority=None):
		"""This will raise InvalidDependString if necessary. If trees is
		None then self._filtered_trees is used."""
		pkgsettings = self.pkgsettings[root]
		if trees is None:
			trees = self._filtered_trees
		if not getattr(priority, "buildtime", False):
			# The parent should only be passed to dep_check() for buildtime
			# dependencies since that's the only case when it's appropriate
			# to trigger the circular dependency avoidance code which uses it.
			# It's important not to trigger the same circular dependency
			# avoidance code for runtime dependencies since it's not needed
			# and it can promote an incorrect package choice.
			parent = None
		if True:
			try:
				if parent is not None:
					trees[root]["parent"] = parent
				if not strict:
					portage.dep._dep_check_strict = False
				mycheck = portage.dep_check(depstring, None,
					pkgsettings, myuse=myuse,
					myroot=root, trees=trees)
			finally:
				if parent is not None:
					trees[root].pop("parent")
				portage.dep._dep_check_strict = True
			if not mycheck[0]:
				raise portage.exception.InvalidDependString(mycheck[1])
			selected_atoms = mycheck[1]
		return selected_atoms

	def _show_unsatisfied_dep(self, root, atom, myparent=None, arg=None):
		atom = portage.dep.Atom(atom)
		atom_set = InternalPackageSet(initial_atoms=(atom,))
		atom_without_use = atom
		if atom.use:
			atom_without_use = portage.dep.remove_slot(atom)
			if atom.slot:
				atom_without_use += ":" + atom.slot
			atom_without_use = portage.dep.Atom(atom_without_use)
		xinfo = '"%s"' % atom
		if arg:
			xinfo='"%s"' % arg
		# Discard null/ from failed cpv_expand category expansion.
		xinfo = xinfo.replace("null/", "")
		masked_packages = []
		missing_use = []
		masked_pkg_instances = set()
		missing_licenses = []
		have_eapi_mask = False
		pkgsettings = self.pkgsettings[root]
		implicit_iuse = pkgsettings._get_implicit_iuse()
		root_config = self.roots[root]
		portdb = self.roots[root].trees["porttree"].dbapi
		dbs = self._filtered_trees[root]["dbs"]
		for db, pkg_type, built, installed, db_keys in dbs:
			if installed:
				continue
			match = db.match
			if hasattr(db, "xmatch"):
				cpv_list = db.xmatch("match-all", atom_without_use)
			else:
				cpv_list = db.match(atom_without_use)
			# descending order
			cpv_list.reverse()
			for cpv in cpv_list:
				metadata, mreasons  = get_mask_info(root_config, cpv,
					pkgsettings, db, pkg_type, built, installed, db_keys)
				if metadata is not None:
					pkg = Package(built=built, cpv=cpv,
						installed=installed, metadata=metadata,
						root_config=root_config)
					if pkg.cp != atom.cp:
						# A cpv can be returned from dbapi.match() as an
						# old-style virtual match even in cases when the
						# package does not actually PROVIDE the virtual.
						# Filter out any such false matches here.
						if not atom_set.findAtomForPackage(pkg):
							continue
					if mreasons:
						masked_pkg_instances.add(pkg)
					if atom.use:
						missing_use.append(pkg)
						if not mreasons:
							continue
				masked_packages.append(
					(root_config, pkgsettings, cpv, metadata, mreasons))

		missing_use_reasons = []
		missing_iuse_reasons = []
		for pkg in missing_use:
			use = pkg.use.enabled
			iuse = implicit_iuse.union(re.escape(x) for x in pkg.iuse.all)
			iuse_re = re.compile("^(%s)$" % "|".join(iuse))
			missing_iuse = []
			for x in atom.use.required:
				if iuse_re.match(x) is None:
					missing_iuse.append(x)
			mreasons = []
			if missing_iuse:
				mreasons.append("Missing IUSE: %s" % " ".join(missing_iuse))
				missing_iuse_reasons.append((pkg, mreasons))
			else:
				need_enable = sorted(atom.use.enabled.difference(use))
				need_disable = sorted(atom.use.disabled.intersection(use))
				if need_enable or need_disable:
					changes = []
					changes.extend(colorize("red", "+" + x) \
						for x in need_enable)
					changes.extend(colorize("blue", "-" + x) \
						for x in need_disable)
					mreasons.append("Change USE: %s" % " ".join(changes))
					missing_use_reasons.append((pkg, mreasons))

		unmasked_use_reasons = [(pkg, mreasons) for (pkg, mreasons) \
			in missing_use_reasons if pkg not in masked_pkg_instances]

		unmasked_iuse_reasons = [(pkg, mreasons) for (pkg, mreasons) \
			in missing_iuse_reasons if pkg not in masked_pkg_instances]

		show_missing_use = False
		if unmasked_use_reasons:
			# Only show the latest version.
			show_missing_use = unmasked_use_reasons[:1]
		elif unmasked_iuse_reasons:
			if missing_use_reasons:
				# All packages with required IUSE are masked,
				# so display a normal masking message.
				pass
			else:
				show_missing_use = unmasked_iuse_reasons

		if show_missing_use:
			print "\nemerge: there are no ebuilds built with USE flags to satisfy "+green(xinfo)+"."
			print "!!! One of the following packages is required to complete your request:"
			for pkg, mreasons in show_missing_use:
				print "- "+pkg.cpv+" ("+", ".join(mreasons)+")"

		elif masked_packages:
			print "\n!!! " + \
				colorize("BAD", "All ebuilds that could satisfy ") + \
				colorize("INFORM", xinfo) + \
				colorize("BAD", " have been masked.")
			print "!!! One of the following masked packages is required to complete your request:"
			have_eapi_mask = show_masked_packages(masked_packages)
			if have_eapi_mask:
				print
				msg = ("The current version of portage supports " + \
					"EAPI '%s'. You must upgrade to a newer version" + \
					" of portage before EAPI masked packages can" + \
					" be installed.") % portage.const.EAPI
				from textwrap import wrap
				for line in wrap(msg, 75):
					print line
			print
			show_mask_docs()
		else:
			print "\nemerge: there are no ebuilds to satisfy "+green(xinfo)+"."

		# Show parent nodes and the argument that pulled them in.
		traversed_nodes = set()
		node = myparent
		msg = []
		while node is not None:
			traversed_nodes.add(node)
			msg.append('(dependency required by "%s" [%s])' % \
				(colorize('INFORM', str(node.cpv)), node.type_name))
			# When traversing to parents, prefer arguments over packages
			# since arguments are root nodes. Never traverse the same
			# package twice, in order to prevent an infinite loop.
			selected_parent = None
			for parent in self.digraph.parent_nodes(node):
				if isinstance(parent, DependencyArg):
					msg.append('(dependency required by "%s" [argument])' % \
						(colorize('INFORM', str(parent))))
					selected_parent = None
					break
				if parent not in traversed_nodes:
					selected_parent = parent
			node = selected_parent
		for line in msg:
			print line

		print

	def _select_pkg_highest_available(self, root, atom, onlydeps=False):
		cache_key = (root, atom, onlydeps)
		ret = self._highest_pkg_cache.get(cache_key)
		if ret is not None:
			pkg, existing = ret
			if pkg and not existing:
				existing = self._slot_pkg_map[root].get(pkg.slot_atom)
				if existing and existing == pkg:
					# Update the cache to reflect that the
					# package has been added to the graph.
					ret = pkg, pkg
					self._highest_pkg_cache[cache_key] = ret
			return ret
		ret = self._select_pkg_highest_available_imp(root, atom, onlydeps=onlydeps)
		self._highest_pkg_cache[cache_key] = ret
		pkg, existing = ret
		if pkg is not None:
			settings = pkg.root_config.settings
			if visible(settings, pkg) and not (pkg.installed and \
				settings._getMissingKeywords(pkg.cpv, pkg.metadata)):
				pkg.root_config.visible_pkgs.cpv_inject(pkg)
		return ret

	def _select_pkg_highest_available_imp(self, root, atom, onlydeps=False):
		root_config = self.roots[root]
		pkgsettings = self.pkgsettings[root]
		dbs = self._filtered_trees[root]["dbs"]
		vardb = self.roots[root].trees["vartree"].dbapi
		portdb = self.roots[root].trees["porttree"].dbapi
		# List of acceptable packages, ordered by type preference.
		matched_packages = []
		highest_version = None
		if not isinstance(atom, portage.dep.Atom):
			atom = portage.dep.Atom(atom)
		atom_cp = atom.cp
		atom_set = InternalPackageSet(initial_atoms=(atom,))
		existing_node = None
		myeb = None
		usepkgonly = "--usepkgonly" in self.myopts
		empty = "empty" in self.myparams
		selective = "selective" in self.myparams
		reinstall = False
		noreplace = "--noreplace" in self.myopts
		# Behavior of the "selective" parameter depends on
		# whether or not a package matches an argument atom.
		# If an installed package provides an old-style
		# virtual that is no longer provided by an available
		# package, the installed package may match an argument
		# atom even though none of the available packages do.
		# Therefore, "selective" logic does not consider
		# whether or not an installed package matches an
		# argument atom. It only considers whether or not
		# available packages match argument atoms, which is
		# represented by the found_available_arg flag.
		found_available_arg = False
		for find_existing_node in True, False:
			if existing_node:
				break
			for db, pkg_type, built, installed, db_keys in dbs:
				if existing_node:
					break
				if installed and not find_existing_node:
					want_reinstall = reinstall or empty or \
						(found_available_arg and not selective)
					if want_reinstall and matched_packages:
						continue
				if hasattr(db, "xmatch"):
					cpv_list = db.xmatch("match-all", atom)
				else:
					cpv_list = db.match(atom)

				# USE=multislot can make an installed package appear as if
				# it doesn't satisfy a slot dependency. Rebuilding the ebuild
				# won't do any good as long as USE=multislot is enabled since
				# the newly built package still won't have the expected slot.
				# Therefore, assume that such SLOT dependencies are already
				# satisfied rather than forcing a rebuild.
				if installed and not cpv_list and atom.slot:
					for cpv in db.match(atom.cp):
						slot_available = False
						for other_db, other_type, other_built, \
							other_installed, other_keys in dbs:
							try:
								if atom.slot == \
									other_db.aux_get(cpv, ["SLOT"])[0]:
									slot_available = True
									break
							except KeyError:
								pass
						if not slot_available:
							continue
						inst_pkg = self._pkg(cpv, "installed",
							root_config, installed=installed)
						# Remove the slot from the atom and verify that
						# the package matches the resulting atom.
						atom_without_slot = portage.dep.remove_slot(atom)
						if atom.use:
							atom_without_slot += str(atom.use)
						atom_without_slot = portage.dep.Atom(atom_without_slot)
						if portage.match_from_list(
							atom_without_slot, [inst_pkg]):
							cpv_list = [inst_pkg.cpv]
						break

				if not cpv_list:
					continue
				pkg_status = "merge"
				if installed or onlydeps:
					pkg_status = "nomerge"
				# descending order
				cpv_list.reverse()
				for cpv in cpv_list:
					# Make --noreplace take precedence over --newuse.
					if not installed and noreplace and \
						cpv in vardb.match(atom):
						# If the installed version is masked, it may
						# be necessary to look at lower versions,
						# in case there is a visible downgrade.
						continue
					reinstall_for_flags = None
					cache_key = (pkg_type, root, cpv, pkg_status)
					calculated_use = True
					pkg = self._pkg_cache.get(cache_key)
					if pkg is None:
						calculated_use = False
						try:
							metadata = izip(db_keys, db.aux_get(cpv, db_keys))
						except KeyError:
							continue
						pkg = Package(built=built, cpv=cpv,
							installed=installed, metadata=metadata,
							onlydeps=onlydeps, root_config=root_config,
							type_name=pkg_type)
						metadata = pkg.metadata
						if not built:
							metadata['CHOST'] = pkgsettings.get('CHOST', '')
						if not built and ("?" in metadata["LICENSE"] or \
							"?" in metadata["PROVIDE"]):
							# This is avoided whenever possible because
							# it's expensive. It only needs to be done here
							# if it has an effect on visibility.
							pkgsettings.setcpv(pkg)
							metadata["USE"] = pkgsettings["PORTAGE_USE"]
							calculated_use = True
						self._pkg_cache[pkg] = pkg

					if not installed or (built and matched_packages):
						# Only enforce visibility on installed packages
						# if there is at least one other visible package
						# available. By filtering installed masked packages
						# here, packages that have been masked since they
						# were installed can be automatically downgraded
						# to an unmasked version.
						try:
							if not visible(pkgsettings, pkg):
								continue
						except portage.exception.InvalidDependString:
							if not installed:
								continue

						# Enable upgrade or downgrade to a version
						# with visible KEYWORDS when the installed
						# version is masked by KEYWORDS, but never
						# reinstall the same exact version only due
						# to a KEYWORDS mask.
						if built and matched_packages:

							different_version = None
							for avail_pkg in matched_packages:
								if not portage.dep.cpvequal(
									pkg.cpv, avail_pkg.cpv):
									different_version = avail_pkg
									break
							if different_version is not None:

								if installed and \
									pkgsettings._getMissingKeywords(
									pkg.cpv, pkg.metadata):
									continue

								# If the ebuild no longer exists or it's
								# keywords have been dropped, reject built
								# instances (installed or binary).
								# If --usepkgonly is enabled, assume that
								# the ebuild status should be ignored.
								if not usepkgonly:
									try:
										pkg_eb = self._pkg(
											pkg.cpv, "ebuild", root_config)
									except portage.exception.PackageNotFound:
										continue
									else:
										if not visible(pkgsettings, pkg_eb):
											continue

					if not pkg.built and not calculated_use:
						# This is avoided whenever possible because
						# it's expensive.
						pkgsettings.setcpv(pkg)
						pkg.metadata["USE"] = pkgsettings["PORTAGE_USE"]

					if pkg.cp != atom.cp:
						# A cpv can be returned from dbapi.match() as an
						# old-style virtual match even in cases when the
						# package does not actually PROVIDE the virtual.
						# Filter out any such false matches here.
						if not atom_set.findAtomForPackage(pkg):
							continue

					myarg = None
					if root == self.target_root:
						try:
							# Ebuild USE must have been calculated prior
							# to this point, in case atoms have USE deps.
							myarg = self._iter_atoms_for_pkg(pkg).next()
						except StopIteration:
							pass
						except portage.exception.InvalidDependString:
							if not installed:
								# masked by corruption
								continue
					if not installed and myarg:
						found_available_arg = True

					if atom.use and not pkg.built:
						use = pkg.use.enabled
						if atom.use.enabled.difference(use):
							continue
						if atom.use.disabled.intersection(use):
							continue
					if pkg.cp == atom_cp:
						if highest_version is None:
							highest_version = pkg
						elif pkg > highest_version:
							highest_version = pkg
					# At this point, we've found the highest visible
					# match from the current repo. Any lower versions
					# from this repo are ignored, so this so the loop
					# will always end with a break statement below
					# this point.
					if find_existing_node:
						e_pkg = self._slot_pkg_map[root].get(pkg.slot_atom)
						if not e_pkg:
							break
						if portage.dep.match_from_list(atom, [e_pkg]):
							if highest_version and \
								e_pkg.cp == atom_cp and \
								e_pkg < highest_version and \
								e_pkg.slot_atom != highest_version.slot_atom:
								# There is a higher version available in a
								# different slot, so this existing node is
								# irrelevant.
								pass
							else:
								matched_packages.append(e_pkg)
								existing_node = e_pkg
						break
					# Compare built package to current config and
					# reject the built package if necessary.
					if built and not installed and \
						("--newuse" in self.myopts or \
						"--reinstall" in self.myopts):
						iuses = pkg.iuse.all
						old_use = pkg.use.enabled
						if myeb:
							pkgsettings.setcpv(myeb)
						else:
							pkgsettings.setcpv(pkg)
						now_use = pkgsettings["PORTAGE_USE"].split()
						forced_flags = set()
						forced_flags.update(pkgsettings.useforce)
						forced_flags.update(pkgsettings.usemask)
						cur_iuse = iuses
						if myeb and not usepkgonly:
							cur_iuse = myeb.iuse.all
						if self._reinstall_for_flags(forced_flags,
							old_use, iuses,
							now_use, cur_iuse):
							break
					# Compare current config to installed package
					# and do not reinstall if possible.
					if not installed and \
						("--newuse" in self.myopts or \
						"--reinstall" in self.myopts) and \
						cpv in vardb.match(atom):
						pkgsettings.setcpv(pkg)
						forced_flags = set()
						forced_flags.update(pkgsettings.useforce)
						forced_flags.update(pkgsettings.usemask)
						old_use = vardb.aux_get(cpv, ["USE"])[0].split()
						old_iuse = set(filter_iuse_defaults(
							vardb.aux_get(cpv, ["IUSE"])[0].split()))
						cur_use = pkgsettings["PORTAGE_USE"].split()
						cur_iuse = pkg.iuse.all
						reinstall_for_flags = \
							self._reinstall_for_flags(
							forced_flags, old_use, old_iuse,
							cur_use, cur_iuse)
						if reinstall_for_flags:
							reinstall = True
					if not built:
						myeb = pkg
					matched_packages.append(pkg)
					if reinstall_for_flags:
						self._reinstall_nodes[pkg] = \
							reinstall_for_flags
					break

		if not matched_packages:
			return None, None

		if "--debug" in self.myopts:
			for pkg in matched_packages:
				portage.writemsg("%s %s\n" % \
					((pkg.type_name + ":").rjust(10), pkg.cpv), noiselevel=-1)

		# Filter out any old-style virtual matches if they are
		# mixed with new-style virtual matches.
		cp = portage.dep_getkey(atom)
		if len(matched_packages) > 1 and \
			"virtual" == portage.catsplit(cp)[0]:
			for pkg in matched_packages:
				if pkg.cp != cp:
					continue
				# Got a new-style virtual, so filter
				# out any old-style virtuals.
				matched_packages = [pkg for pkg in matched_packages \
					if pkg.cp == cp]
				break

		if len(matched_packages) > 1:
			bestmatch = portage.best(
				[pkg.cpv for pkg in matched_packages])
			matched_packages = [pkg for pkg in matched_packages \
				if portage.dep.cpvequal(pkg.cpv, bestmatch)]

		# ordered by type preference ("ebuild" type is the last resort)
		return  matched_packages[-1], existing_node

	def _select_pkg_from_graph(self, root, atom, onlydeps=False):
		"""
		Select packages that have already been added to the graph or
		those that are installed and have not been scheduled for
		replacement.
		"""
		graph_db = self._graph_trees[root]["porttree"].dbapi
		matches = graph_db.match_pkgs(atom)
		if not matches:
			return None, None
		pkg = matches[-1] # highest match
		in_graph = self._slot_pkg_map[root].get(pkg.slot_atom)
		return pkg, in_graph

	def _complete_graph(self):
		"""
		Add any deep dependencies of required sets (args, system, world) that
		have not been pulled into the graph yet. This ensures that the graph
		is consistent such that initially satisfied deep dependencies are not
		broken in the new graph. Initially unsatisfied dependencies are
		irrelevant since we only want to avoid breaking dependencies that are
		intially satisfied.

		Since this method can consume enough time to disturb users, it is
		currently only enabled by the --complete-graph option.
		"""
		if "--buildpkgonly" in self.myopts or \
			"recurse" not in self.myparams:
			return 1

		if "complete" not in self.myparams:
			# Skip this to avoid consuming enough time to disturb users.
			return 1

		# Put the depgraph into a mode that causes it to only
		# select packages that have already been added to the
		# graph or those that are installed and have not been
		# scheduled for replacement. Also, toggle the "deep"
		# parameter so that all dependencies are traversed and
		# accounted for.
		self._select_atoms = self._select_atoms_from_graph
		self._select_package = self._select_pkg_from_graph
		already_deep = "deep" in self.myparams
		if not already_deep:
			self.myparams.add("deep")

		for root in self.roots:
			required_set_names = self._required_set_names.copy()
			if root == self.target_root and \
				(already_deep or "empty" in self.myparams):
				required_set_names.difference_update(self._sets)
			if not required_set_names and not self._ignored_deps:
				continue
			root_config = self.roots[root]
			setconfig = root_config.setconfig
			args = []
			# Reuse existing SetArg instances when available.
			for arg in self.digraph.root_nodes():
				if not isinstance(arg, SetArg):
					continue
				if arg.root_config != root_config:
					continue
				if arg.name in required_set_names:
					args.append(arg)
					required_set_names.remove(arg.name)
			# Create new SetArg instances only when necessary.
			for s in required_set_names:
				expanded_set = InternalPackageSet(
					initial_atoms=setconfig.getSetAtoms(s))
				atom = SETPREFIX + s
				args.append(SetArg(arg=atom, set=expanded_set,
					root_config=root_config))
			vardb = root_config.trees["vartree"].dbapi
			for arg in args:
				for atom in arg.set:
					self._dep_stack.append(
						Dependency(atom=atom, root=root, parent=arg))
			if self._ignored_deps:
				self._dep_stack.extend(self._ignored_deps)
				self._ignored_deps = []
			if not self._create_graph(allow_unsatisfied=True):
				return 0
			# Check the unsatisfied deps to see if any initially satisfied deps
			# will become unsatisfied due to an upgrade. Initially unsatisfied
			# deps are irrelevant since we only want to avoid breaking deps
			# that are initially satisfied.
			while self._unsatisfied_deps:
				dep = self._unsatisfied_deps.pop()
				matches = vardb.match_pkgs(dep.atom)
				if not matches:
					self._initially_unsatisfied_deps.append(dep)
					continue
				# An scheduled installation broke a deep dependency.
				# Add the installed package to the graph so that it
				# will be appropriately reported as a slot collision
				# (possibly solvable via backtracking).
				pkg = matches[-1] # highest match
				if not self._add_pkg(pkg, dep):
					return 0
				if not self._create_graph(allow_unsatisfied=True):
					return 0
		return 1

	def _pkg(self, cpv, type_name, root_config, installed=False):
		"""
		Get a package instance from the cache, or create a new
		one if necessary. Raises KeyError from aux_get if it
		failures for some reason (package does not exist or is
		corrupt).
		"""
		operation = "merge"
		if installed:
			operation = "nomerge"
		pkg = self._pkg_cache.get(
			(type_name, root_config.root, cpv, operation))
		if pkg is None:
			tree_type = self.pkg_tree_map[type_name]
			db = root_config.trees[tree_type].dbapi
			db_keys = list(self._trees_orig[root_config.root][
				tree_type].dbapi._aux_cache_keys)
			try:
				metadata = izip(db_keys, db.aux_get(cpv, db_keys))
			except KeyError:
				raise portage.exception.PackageNotFound(cpv)
			pkg = Package(cpv=cpv, metadata=metadata,
				root_config=root_config, installed=installed)
			if type_name == "ebuild":
				settings = self.pkgsettings[root_config.root]
				settings.setcpv(pkg)
				pkg.metadata["USE"] = settings["PORTAGE_USE"]
				pkg.metadata['CHOST'] = settings.get('CHOST', '')
			self._pkg_cache[pkg] = pkg
		return pkg

	def validate_blockers(self):
		"""Remove any blockers from the digraph that do not match any of the
		packages within the graph.  If necessary, create hard deps to ensure
		correct merge order such that mutually blocking packages are never
		installed simultaneously."""

		if "--buildpkgonly" in self.myopts or \
			"--nodeps" in self.myopts:
			return True

		#if "deep" in self.myparams:
		if True:
			# Pull in blockers from all installed packages that haven't already
			# been pulled into the depgraph.  This is not enabled by default
			# due to the performance penalty that is incurred by all the
			# additional dep_check calls that are required.

			dep_keys = ["DEPEND","RDEPEND","PDEPEND"]
			for myroot in self.trees:
				vardb = self.trees[myroot]["vartree"].dbapi
				portdb = self.trees[myroot]["porttree"].dbapi
				pkgsettings = self.pkgsettings[myroot]
				final_db = self.mydbapi[myroot]

				blocker_cache = BlockerCache(myroot, vardb)
				stale_cache = set(blocker_cache)
				for pkg in vardb:
					cpv = pkg.cpv
					stale_cache.discard(cpv)
					pkg_in_graph = self.digraph.contains(pkg)

					# Check for masked installed packages. Only warn about
					# packages that are in the graph in order to avoid warning
					# about those that will be automatically uninstalled during
					# the merge process or by --depclean.
					if pkg in final_db:
						if pkg_in_graph and not visible(pkgsettings, pkg):
							self._masked_installed.add(pkg)

					blocker_atoms = None
					blockers = None
					if pkg_in_graph:
						blockers = []
						try:
							blockers.extend(
								self._blocker_parents.child_nodes(pkg))
						except KeyError:
							pass
						try:
							blockers.extend(
								self._irrelevant_blockers.child_nodes(pkg))
						except KeyError:
							pass
					if blockers is not None:
						blockers = set(str(blocker.atom) \
							for blocker in blockers)

					# If this node has any blockers, create a "nomerge"
					# node for it so that they can be enforced.
					self.spinner.update()
					blocker_data = blocker_cache.get(cpv)
					if blocker_data is not None and \
						blocker_data.counter != long(pkg.metadata["COUNTER"]):
						blocker_data = None

					# If blocker data from the graph is available, use
					# it to validate the cache and update the cache if
					# it seems invalid.
					if blocker_data is not None and \
						blockers is not None:
						if not blockers.symmetric_difference(
							blocker_data.atoms):
							continue
						blocker_data = None

					if blocker_data is None and \
						blockers is not None:
						# Re-use the blockers from the graph.
						blocker_atoms = sorted(blockers)
						counter = long(pkg.metadata["COUNTER"])
						blocker_data = \
							blocker_cache.BlockerData(counter, blocker_atoms)
						blocker_cache[pkg.cpv] = blocker_data
						continue

					if blocker_data:
						blocker_atoms = blocker_data.atoms
					else:
						# Use aux_get() to trigger FakeVartree global
						# updates on *DEPEND when appropriate.
						depstr = " ".join(vardb.aux_get(pkg.cpv, dep_keys))
						# It is crucial to pass in final_db here in order to
						# optimize dep_check calls by eliminating atoms via
						# dep_wordreduce and dep_eval calls.
						try:
							portage.dep._dep_check_strict = False
							try:
								success, atoms = portage.dep_check(depstr,
									final_db, pkgsettings, myuse=pkg.use.enabled,
									trees=self._graph_trees, myroot=myroot)
							except Exception, e:
								if isinstance(e, SystemExit):
									raise
								# This is helpful, for example, if a ValueError
								# is thrown from cpv_expand due to multiple
								# matches (this can happen if an atom lacks a
								# category).
								show_invalid_depstring_notice(
									pkg, depstr, str(e))
								del e
								raise
						finally:
							portage.dep._dep_check_strict = True
						if not success:
							replacement_pkg = final_db.match_pkgs(pkg.slot_atom)
							if replacement_pkg and \
								replacement_pkg[0].operation == "merge":
								# This package is being replaced anyway, so
								# ignore invalid dependencies so as not to
								# annoy the user too much (otherwise they'd be
								# forced to manually unmerge it first).
								continue
							show_invalid_depstring_notice(pkg, depstr, atoms)
							return False
						blocker_atoms = [myatom for myatom in atoms \
							if myatom.startswith("!")]
						blocker_atoms.sort()
						counter = long(pkg.metadata["COUNTER"])
						blocker_cache[cpv] = \
							blocker_cache.BlockerData(counter, blocker_atoms)
					if blocker_atoms:
						try:
							for atom in blocker_atoms:
								blocker = Blocker(atom=portage.dep.Atom(atom),
									eapi=pkg.metadata["EAPI"], root=myroot)
								self._blocker_parents.add(blocker, pkg)
						except portage.exception.InvalidAtom, e:
							depstr = " ".join(vardb.aux_get(pkg.cpv, dep_keys))
							show_invalid_depstring_notice(
								pkg, depstr, "Invalid Atom: %s" % (e,))
							return False
				for cpv in stale_cache:
					del blocker_cache[cpv]
				blocker_cache.flush()
				del blocker_cache

		# Discard any "uninstall" tasks scheduled by previous calls
		# to this method, since those tasks may not make sense given
		# the current graph state.
		previous_uninstall_tasks = self._blocker_uninstalls.leaf_nodes()
		if previous_uninstall_tasks:
			self._blocker_uninstalls = digraph()
			self.digraph.difference_update(previous_uninstall_tasks)

		for blocker in self._blocker_parents.leaf_nodes():
			self.spinner.update()
			root_config = self.roots[blocker.root]
			virtuals = root_config.settings.getvirtuals()
			myroot = blocker.root
			initial_db = self.trees[myroot]["vartree"].dbapi
			final_db = self.mydbapi[myroot]
			
			provider_virtual = False
			if blocker.cp in virtuals and \
				not self._have_new_virt(blocker.root, blocker.cp):
				provider_virtual = True

			if provider_virtual:
				atoms = []
				for provider_entry in virtuals[blocker.cp]:
					provider_cp = \
						portage.dep_getkey(provider_entry)
					atoms.append(blocker.atom.replace(
						blocker.cp, provider_cp))
			else:
				atoms = [blocker.atom]

			blocked_initial = []
			for atom in atoms:
				blocked_initial.extend(initial_db.match_pkgs(atom))

			blocked_final = []
			for atom in atoms:
				blocked_final.extend(final_db.match_pkgs(atom))

			if not blocked_initial and not blocked_final:
				parent_pkgs = self._blocker_parents.parent_nodes(blocker)
				self._blocker_parents.remove(blocker)
				# Discard any parents that don't have any more blockers.
				for pkg in parent_pkgs:
					self._irrelevant_blockers.add(blocker, pkg)
					if not self._blocker_parents.child_nodes(pkg):
						self._blocker_parents.remove(pkg)
				continue
			for parent in self._blocker_parents.parent_nodes(blocker):
				unresolved_blocks = False
				depends_on_order = set()
				for pkg in blocked_initial:
					if pkg.slot_atom == parent.slot_atom:
						# TODO: Support blocks within slots in cases where it
						# might make sense.  For example, a new version might
						# require that the old version be uninstalled at build
						# time.
						continue
					if parent.installed:
						# Two currently installed packages conflict with
						# eachother. Ignore this case since the damage
						# is already done and this would be likely to
						# confuse users if displayed like a normal blocker.
						continue

					self._blocked_pkgs.add(pkg, blocker)

					if parent.operation == "merge":
						# Maybe the blocked package can be replaced or simply
						# unmerged to resolve this block.
						depends_on_order.add((pkg, parent))
						continue
					# None of the above blocker resolutions techniques apply,
					# so apparently this one is unresolvable.
					unresolved_blocks = True
				for pkg in blocked_final:
					if pkg.slot_atom == parent.slot_atom:
						# TODO: Support blocks within slots.
						continue
					if parent.operation == "nomerge" and \
						pkg.operation == "nomerge":
						# This blocker will be handled the next time that a
						# merge of either package is triggered.
						continue

					self._blocked_pkgs.add(pkg, blocker)

					# Maybe the blocking package can be
					# unmerged to resolve this block.
					if parent.operation == "merge" and pkg.installed:
						depends_on_order.add((pkg, parent))
						continue
					elif parent.operation == "nomerge":
						depends_on_order.add((parent, pkg))
						continue
					# None of the above blocker resolutions techniques apply,
					# so apparently this one is unresolvable.
					unresolved_blocks = True

				# Make sure we don't unmerge any package that have been pulled
				# into the graph.
				if not unresolved_blocks and depends_on_order:
					for inst_pkg, inst_task in depends_on_order:
						if self.digraph.contains(inst_pkg) and \
							self.digraph.parent_nodes(inst_pkg):
							unresolved_blocks = True
							break

				if not unresolved_blocks and depends_on_order:
					for inst_pkg, inst_task in depends_on_order:
						uninst_task = Package(built=inst_pkg.built,
							cpv=inst_pkg.cpv, installed=inst_pkg.installed,
							metadata=inst_pkg.metadata,
							operation="uninstall",
							root_config=inst_pkg.root_config,
							type_name=inst_pkg.type_name)
						self._pkg_cache[uninst_task] = uninst_task
						# Enforce correct merge order with a hard dep.
						self.digraph.addnode(uninst_task, inst_task,
							priority=BlockerDepPriority.instance)
						# Count references to this blocker so that it can be
						# invalidated after nodes referencing it have been
						# merged.
						self._blocker_uninstalls.addnode(uninst_task, blocker)
				if not unresolved_blocks and not depends_on_order:
					self._irrelevant_blockers.add(blocker, parent)
					self._blocker_parents.remove_edge(blocker, parent)
					if not self._blocker_parents.parent_nodes(blocker):
						self._blocker_parents.remove(blocker)
					if not self._blocker_parents.child_nodes(parent):
						self._blocker_parents.remove(parent)
				if unresolved_blocks:
					self._unsolvable_blockers.add(blocker, parent)

		return True

	def _accept_blocker_conflicts(self):
		acceptable = False
		for x in ("--buildpkgonly", "--fetchonly",
			"--fetch-all-uri", "--nodeps"):
			if x in self.myopts:
				acceptable = True
				break
		return acceptable

	def _merge_order_bias(self, mygraph):
		"""
		For optimal leaf node selection, promote deep system runtime deps and
		order nodes from highest to lowest overall reference count.
		"""

		node_info = {}
		for node in mygraph.order:
			node_info[node] = len(mygraph.parent_nodes(node))
		deep_system_deps = _find_deep_system_runtime_deps(mygraph)

		def cmp_merge_preference(node1, node2):

			if node1.operation == 'uninstall':
				if node2.operation == 'uninstall':
					return 0
				return 1

			if node2.operation == 'uninstall':
				if node1.operation == 'uninstall':
					return 0
				return -1

			node1_sys = node1 in deep_system_deps
			node2_sys = node2 in deep_system_deps
			if node1_sys != node2_sys:
				if node1_sys:
					return -1
				return 1

			return node_info[node2] - node_info[node1]

		mygraph.order.sort(key=cmp_sort_key(cmp_merge_preference))

	def altlist(self, reversed=False):

		while self._serialized_tasks_cache is None:
			self._resolve_conflicts()
			try:
				self._serialized_tasks_cache, self._scheduler_graph = \
					self._serialize_tasks()
			except self._serialize_tasks_retry:
				pass

		retlist = self._serialized_tasks_cache[:]
		if reversed:
			retlist.reverse()
		return retlist

	def schedulerGraph(self):
		"""
		The scheduler graph is identical to the normal one except that
		uninstall edges are reversed in specific cases that require
		conflicting packages to be temporarily installed simultaneously.
		This is intended for use by the Scheduler in it's parallelization
		logic. It ensures that temporary simultaneous installation of
		conflicting packages is avoided when appropriate (especially for
		!!atom blockers), but allowed in specific cases that require it.

		Note that this method calls break_refs() which alters the state of
		internal Package instances such that this depgraph instance should
		not be used to perform any more calculations.
		"""
		if self._scheduler_graph is None:
			self.altlist()
		self.break_refs(self._scheduler_graph.order)
		return self._scheduler_graph

	def break_refs(self, nodes):
		"""
		Take a mergelist like that returned from self.altlist() and
		break any references that lead back to the depgraph. This is
		useful if you want to hold references to packages without
		also holding the depgraph on the heap.
		"""
		for node in nodes:
			if hasattr(node, "root_config"):
				# The FakeVartree references the _package_cache which
				# references the depgraph. So that Package instances don't
				# hold the depgraph and FakeVartree on the heap, replace
				# the RootConfig that references the FakeVartree with the
				# original RootConfig instance which references the actual
				# vartree.
				node.root_config = \
					self._trees_orig[node.root_config.root]["root_config"]

	def _resolve_conflicts(self):
		if not self._complete_graph():
			raise self._unknown_internal_error()

		if not self.validate_blockers():
			raise self._unknown_internal_error()

		if self._slot_collision_info:
			self._process_slot_conflicts()

	def _serialize_tasks(self):

		if "--debug" in self.myopts:
			writemsg("\ndigraph:\n\n", noiselevel=-1)
			self.digraph.debug_print()
			writemsg("\n", noiselevel=-1)

		scheduler_graph = self.digraph.copy()
		mygraph=self.digraph.copy()
		# Prune "nomerge" root nodes if nothing depends on them, since
		# otherwise they slow down merge order calculation. Don't remove
		# non-root nodes since they help optimize merge order in some cases
		# such as revdep-rebuild.
		removed_nodes = set()
		while True:
			for node in mygraph.root_nodes():
				if not isinstance(node, Package) or \
					node.installed or node.onlydeps:
					removed_nodes.add(node)
			if removed_nodes:
				self.spinner.update()
				mygraph.difference_update(removed_nodes)
			if not removed_nodes:
				break
			removed_nodes.clear()
		self._merge_order_bias(mygraph)
		def cmp_circular_bias(n1, n2):
			"""
			RDEPEND is stronger than PDEPEND and this function
			measures such a strength bias within a circular
			dependency relationship.
			"""
			n1_n2_medium = n2 in mygraph.child_nodes(n1,
				ignore_priority=priority_range.ignore_medium_soft)
			n2_n1_medium = n1 in mygraph.child_nodes(n2,
				ignore_priority=priority_range.ignore_medium_soft)
			if n1_n2_medium == n2_n1_medium:
				return 0
			elif n1_n2_medium:
				return 1
			return -1
		myblocker_uninstalls = self._blocker_uninstalls.copy()
		retlist=[]
		# Contains uninstall tasks that have been scheduled to
		# occur after overlapping blockers have been installed.
		scheduled_uninstalls = set()
		# Contains any Uninstall tasks that have been ignored
		# in order to avoid the circular deps code path. These
		# correspond to blocker conflicts that could not be
		# resolved.
		ignored_uninstall_tasks = set()
		have_uninstall_task = False
		complete = "complete" in self.myparams
		asap_nodes = []

		def get_nodes(**kwargs):
			"""
			Returns leaf nodes excluding Uninstall instances
			since those should be executed as late as possible.
			"""
			return [node for node in mygraph.leaf_nodes(**kwargs) \
				if isinstance(node, Package) and \
					(node.operation != "uninstall" or \
					node in scheduled_uninstalls)]

		# sys-apps/portage needs special treatment if ROOT="/"
		running_root = self._running_root.root
		from portage.const import PORTAGE_PACKAGE_ATOM
		runtime_deps = InternalPackageSet(
			initial_atoms=[PORTAGE_PACKAGE_ATOM])
		running_portage = self.trees[running_root]["vartree"].dbapi.match_pkgs(
			PORTAGE_PACKAGE_ATOM)
		replacement_portage = self.mydbapi[running_root].match_pkgs(
			PORTAGE_PACKAGE_ATOM)

		if running_portage:
			running_portage = running_portage[0]
		else:
			running_portage = None

		if replacement_portage:
			replacement_portage = replacement_portage[0]
		else:
			replacement_portage = None

		if replacement_portage == running_portage:
			replacement_portage = None

		if replacement_portage is not None:
			# update from running_portage to replacement_portage asap
			asap_nodes.append(replacement_portage)

		if running_portage is not None:
			try:
				portage_rdepend = self._select_atoms_highest_available(
					running_root, running_portage.metadata["RDEPEND"],
					myuse=running_portage.use.enabled,
					parent=running_portage, strict=False)
			except portage.exception.InvalidDependString, e:
				portage.writemsg("!!! Invalid RDEPEND in " + \
					"'%svar/db/pkg/%s/RDEPEND': %s\n" % \
					(running_root, running_portage.cpv, e), noiselevel=-1)
				del e
				portage_rdepend = []
			runtime_deps.update(atom for atom in portage_rdepend \
				if not atom.startswith("!"))

		def gather_deps(ignore_priority, mergeable_nodes,
			selected_nodes, node):
			"""
			Recursively gather a group of nodes that RDEPEND on
			eachother. This ensures that they are merged as a group
			and get their RDEPENDs satisfied as soon as possible.
			"""
			if node in selected_nodes:
				return True
			if node not in mergeable_nodes:
				return False
			if node == replacement_portage and \
				mygraph.child_nodes(node,
				ignore_priority=priority_range.ignore_medium_soft):
				# Make sure that portage always has all of it's
				# RDEPENDs installed first.
				return False
			selected_nodes.add(node)
			for child in mygraph.child_nodes(node,
				ignore_priority=ignore_priority):
				if not gather_deps(ignore_priority,
					mergeable_nodes, selected_nodes, child):
					return False
			return True

		def ignore_uninst_or_med(priority):
			if priority is BlockerDepPriority.instance:
				return True
			return priority_range.ignore_medium(priority)

		def ignore_uninst_or_med_soft(priority):
			if priority is BlockerDepPriority.instance:
				return True
			return priority_range.ignore_medium_soft(priority)

		tree_mode = "--tree" in self.myopts
		# Tracks whether or not the current iteration should prefer asap_nodes
		# if available.  This is set to False when the previous iteration
		# failed to select any nodes.  It is reset whenever nodes are
		# successfully selected.
		prefer_asap = True

		# Controls whether or not the current iteration should drop edges that
		# are "satisfied" by installed packages, in order to solve circular
		# dependencies. The deep runtime dependencies of installed packages are
		# not checked in this case (bug #199856), so it must be avoided
		# whenever possible.
		drop_satisfied = False

		# State of variables for successive iterations that loosen the
		# criteria for node selection.
		#
		# iteration   prefer_asap   drop_satisfied
		# 1           True          False
		# 2           False         False
		# 3           False         True
		#
		# If no nodes are selected on the last iteration, it is due to
		# unresolved blockers or circular dependencies.

		while not mygraph.empty():
			self.spinner.update()
			selected_nodes = None
			ignore_priority = None
			if drop_satisfied or (prefer_asap and asap_nodes):
				priority_range = DepPrioritySatisfiedRange
			else:
				priority_range = DepPriorityNormalRange
			if prefer_asap and asap_nodes:
				# ASAP nodes are merged before their soft deps. Go ahead and
				# select root nodes here if necessary, since it's typical for
				# the parent to have been removed from the graph already.
				asap_nodes = [node for node in asap_nodes \
					if mygraph.contains(node)]
				for node in asap_nodes:
					if not mygraph.child_nodes(node,
						ignore_priority=priority_range.ignore_soft):
						selected_nodes = [node]
						asap_nodes.remove(node)
						break
			if not selected_nodes and \
				not (prefer_asap and asap_nodes):
				for i in xrange(priority_range.NONE,
					priority_range.MEDIUM_SOFT + 1):
					ignore_priority = priority_range.ignore_priority[i]
					nodes = get_nodes(ignore_priority=ignore_priority)
					if nodes:
						# If there is a mix of uninstall nodes with other
						# types, save the uninstall nodes for later since
						# sometimes a merge node will render an uninstall
						# node unnecessary (due to occupying the same slot),
						# and we want to avoid executing a separate uninstall
						# task in that case.
						if len(nodes) > 1:
							good_uninstalls = []
							with_some_uninstalls_excluded = []
							for node in nodes:
								if node.operation == "uninstall":
									slot_node = self.mydbapi[node.root
										].match_pkgs(node.slot_atom)
									if slot_node and \
										slot_node[0].operation == "merge":
										continue
									good_uninstalls.append(node)
								with_some_uninstalls_excluded.append(node)
							if good_uninstalls:
								nodes = good_uninstalls
							elif with_some_uninstalls_excluded:
								nodes = with_some_uninstalls_excluded
							else:
								nodes = nodes

						if ignore_priority is None and not tree_mode:
							# Greedily pop all of these nodes since no
							# relationship has been ignored. This optimization
							# destroys --tree output, so it's disabled in tree
							# mode.
							selected_nodes = nodes
						else:
							# For optimal merge order:
							#  * Only pop one node.
							#  * Removing a root node (node without a parent)
							#    will not produce a leaf node, so avoid it.
							#  * It's normal for a selected uninstall to be a
							#    root node, so don't check them for parents.
							for node in nodes:
								if node.operation == "uninstall" or \
									mygraph.parent_nodes(node):
									selected_nodes = [node]
									break

						if selected_nodes:
							break

			if not selected_nodes:
				nodes = get_nodes(ignore_priority=priority_range.ignore_medium)
				if nodes:
					mergeable_nodes = set(nodes)
					if prefer_asap and asap_nodes:
						nodes = asap_nodes
					for i in xrange(priority_range.SOFT,
						priority_range.MEDIUM_SOFT + 1):
						ignore_priority = priority_range.ignore_priority[i]
						for node in nodes:
							if not mygraph.parent_nodes(node):
								continue
							selected_nodes = set()
							if gather_deps(ignore_priority,
								mergeable_nodes, selected_nodes, node):
								break
							else:
								selected_nodes = None
						if selected_nodes:
							break

					if prefer_asap and asap_nodes and not selected_nodes:
						# We failed to find any asap nodes to merge, so ignore
						# them for the next iteration.
						prefer_asap = False
						continue

			if selected_nodes and ignore_priority is not None:
				# Try to merge ignored medium_soft deps as soon as possible
				# if they're not satisfied by installed packages.
				for node in selected_nodes:
					children = set(mygraph.child_nodes(node))
					soft = children.difference(
						mygraph.child_nodes(node,
						ignore_priority=DepPrioritySatisfiedRange.ignore_soft))
					medium_soft = children.difference(
						mygraph.child_nodes(node,
							ignore_priority = \
							DepPrioritySatisfiedRange.ignore_medium_soft))
					medium_soft.difference_update(soft)
					for child in medium_soft:
						if child in selected_nodes:
							continue
						if child in asap_nodes:
							continue
						asap_nodes.append(child)

			if selected_nodes and len(selected_nodes) > 1:
				if not isinstance(selected_nodes, list):
					selected_nodes = list(selected_nodes)
				selected_nodes.sort(key=cmp_sort_key(cmp_circular_bias))

			if not selected_nodes and not myblocker_uninstalls.is_empty():
				# An Uninstall task needs to be executed in order to
				# avoid conflict if possible.

				if drop_satisfied:
					priority_range = DepPrioritySatisfiedRange
				else:
					priority_range = DepPriorityNormalRange

				mergeable_nodes = get_nodes(
					ignore_priority=ignore_uninst_or_med)

				min_parent_deps = None
				uninst_task = None
				for task in myblocker_uninstalls.leaf_nodes():
					# Do some sanity checks so that system or world packages
					# don't get uninstalled inappropriately here (only really
					# necessary when --complete-graph has not been enabled).

					if task in ignored_uninstall_tasks:
						continue

					if task in scheduled_uninstalls:
						# It's been scheduled but it hasn't
						# been executed yet due to dependence
						# on installation of blocking packages.
						continue

					root_config = self.roots[task.root]
					inst_pkg = self._pkg_cache[
						("installed", task.root, task.cpv, "nomerge")]

					if self.digraph.contains(inst_pkg):
						continue

					forbid_overlap = False
					heuristic_overlap = False
					for blocker in myblocker_uninstalls.parent_nodes(task):
						if blocker.eapi in ("0", "1"):
							heuristic_overlap = True
						elif blocker.atom.blocker.overlap.forbid:
							forbid_overlap = True
							break
					if forbid_overlap and running_root == task.root:
						continue

					if heuristic_overlap and running_root == task.root:
						# Never uninstall sys-apps/portage or it's essential
						# dependencies, except through replacement.
						try:
							runtime_dep_atoms = \
								list(runtime_deps.iterAtomsForPackage(task))
						except portage.exception.InvalidDependString, e:
							portage.writemsg("!!! Invalid PROVIDE in " + \
								"'%svar/db/pkg/%s/PROVIDE': %s\n" % \
								(task.root, task.cpv, e), noiselevel=-1)
							del e
							continue

						# Don't uninstall a runtime dep if it appears
						# to be the only suitable one installed.
						skip = False
						vardb = root_config.trees["vartree"].dbapi
						for atom in runtime_dep_atoms:
							other_version = None
							for pkg in vardb.match_pkgs(atom):
								if pkg.cpv == task.cpv and \
									pkg.metadata["COUNTER"] == \
									task.metadata["COUNTER"]:
									continue
								other_version = pkg
								break
							if other_version is None:
								skip = True
								break
						if skip:
							continue

						# For packages in the system set, don't take
						# any chances. If the conflict can't be resolved
						# by a normal replacement operation then abort.
						skip = False
						try:
							for atom in root_config.sets[
								"system"].iterAtomsForPackage(task):
								skip = True
								break
						except portage.exception.InvalidDependString, e:
							portage.writemsg("!!! Invalid PROVIDE in " + \
								"'%svar/db/pkg/%s/PROVIDE': %s\n" % \
								(task.root, task.cpv, e), noiselevel=-1)
							del e
							skip = True
						if skip:
							continue

					# Note that the world check isn't always
					# necessary since self._complete_graph() will
					# add all packages from the system and world sets to the
					# graph. This just allows unresolved conflicts to be
					# detected as early as possible, which makes it possible
					# to avoid calling self._complete_graph() when it is
					# unnecessary due to blockers triggering an abortion.
					if not complete:
						# For packages in the world set, go ahead an uninstall
						# when necessary, as long as the atom will be satisfied
						# in the final state.
						graph_db = self.mydbapi[task.root]
						skip = False
						try:
							for atom in root_config.sets[
								"world"].iterAtomsForPackage(task):
								satisfied = False
								for pkg in graph_db.match_pkgs(atom):
									if pkg == inst_pkg:
										continue
									satisfied = True
									break
								if not satisfied:
									skip = True
									self._blocked_world_pkgs[inst_pkg] = atom
									break
						except portage.exception.InvalidDependString, e:
							portage.writemsg("!!! Invalid PROVIDE in " + \
								"'%svar/db/pkg/%s/PROVIDE': %s\n" % \
								(task.root, task.cpv, e), noiselevel=-1)
							del e
							skip = True
						if skip:
							continue

					# Check the deps of parent nodes to ensure that
					# the chosen task produces a leaf node. Maybe
					# this can be optimized some more to make the
					# best possible choice, but the current algorithm
					# is simple and should be near optimal for most
					# common cases.
					mergeable_parent = False
					parent_deps = set()
					for parent in mygraph.parent_nodes(task):
						parent_deps.update(mygraph.child_nodes(parent,
							ignore_priority=priority_range.ignore_medium_soft))
						if parent in mergeable_nodes and \
							gather_deps(ignore_uninst_or_med_soft,
							mergeable_nodes, set(), parent):
							mergeable_parent = True

					if not mergeable_parent:
						continue

					parent_deps.remove(task)
					if min_parent_deps is None or \
						len(parent_deps) < min_parent_deps:
						min_parent_deps = len(parent_deps)
						uninst_task = task

				if uninst_task is not None:
					# The uninstall is performed only after blocking
					# packages have been merged on top of it. File
					# collisions between blocking packages are detected
					# and removed from the list of files to be uninstalled.
					scheduled_uninstalls.add(uninst_task)
					parent_nodes = mygraph.parent_nodes(uninst_task)

					# Reverse the parent -> uninstall edges since we want
					# to do the uninstall after blocking packages have
					# been merged on top of it.
					mygraph.remove(uninst_task)
					for blocked_pkg in parent_nodes:
						mygraph.add(blocked_pkg, uninst_task,
							priority=BlockerDepPriority.instance)
						scheduler_graph.remove_edge(uninst_task, blocked_pkg)
						scheduler_graph.add(blocked_pkg, uninst_task,
							priority=BlockerDepPriority.instance)

					# Reset the state variables for leaf node selection and
					# continue trying to select leaf nodes.
					prefer_asap = True
					drop_satisfied = False
					continue

			if not selected_nodes:
				# Only select root nodes as a last resort. This case should
				# only trigger when the graph is nearly empty and the only
				# remaining nodes are isolated (no parents or children). Since
				# the nodes must be isolated, ignore_priority is not needed.
				selected_nodes = get_nodes()

			if not selected_nodes and not drop_satisfied:
				drop_satisfied = True
				continue

			if not selected_nodes and not myblocker_uninstalls.is_empty():
				# If possible, drop an uninstall task here in order to avoid
				# the circular deps code path. The corresponding blocker will
				# still be counted as an unresolved conflict.
				uninst_task = None
				for node in myblocker_uninstalls.leaf_nodes():
					try:
						mygraph.remove(node)
					except KeyError:
						pass
					else:
						uninst_task = node
						ignored_uninstall_tasks.add(node)
						break

				if uninst_task is not None:
					# Reset the state variables for leaf node selection and
					# continue trying to select leaf nodes.
					prefer_asap = True
					drop_satisfied = False
					continue

			if not selected_nodes:
				self._circular_deps_for_display = mygraph
				raise self._unknown_internal_error()

			# At this point, we've succeeded in selecting one or more nodes, so
			# reset state variables for leaf node selection.
			prefer_asap = True
			drop_satisfied = False

			mygraph.difference_update(selected_nodes)

			for node in selected_nodes:
				if isinstance(node, Package) and \
					node.operation == "nomerge":
					continue

				# Handle interactions between blockers
				# and uninstallation tasks.
				solved_blockers = set()
				uninst_task = None
				if isinstance(node, Package) and \
					"uninstall" == node.operation:
					have_uninstall_task = True
					uninst_task = node
				else:
					vardb = self.trees[node.root]["vartree"].dbapi
					previous_cpv = vardb.match(node.slot_atom)
					if previous_cpv:
						# The package will be replaced by this one, so remove
						# the corresponding Uninstall task if necessary.
						previous_cpv = previous_cpv[0]
						uninst_task = \
							("installed", node.root, previous_cpv, "uninstall")
						try:
							mygraph.remove(uninst_task)
						except KeyError:
							pass

				if uninst_task is not None and \
					uninst_task not in ignored_uninstall_tasks and \
					myblocker_uninstalls.contains(uninst_task):
					blocker_nodes = myblocker_uninstalls.parent_nodes(uninst_task)
					myblocker_uninstalls.remove(uninst_task)
					# Discard any blockers that this Uninstall solves.
					for blocker in blocker_nodes:
						if not myblocker_uninstalls.child_nodes(blocker):
							myblocker_uninstalls.remove(blocker)
							solved_blockers.add(blocker)

				retlist.append(node)

				if (isinstance(node, Package) and \
					"uninstall" == node.operation) or \
					(uninst_task is not None and \
					uninst_task in scheduled_uninstalls):
					# Include satisfied blockers in the merge list
					# since the user might be interested and also
					# it serves as an indicator that blocking packages
					# will be temporarily installed simultaneously.
					for blocker in solved_blockers:
						retlist.append(Blocker(atom=blocker.atom,
							root=blocker.root, eapi=blocker.eapi,
							satisfied=True))

		unsolvable_blockers = set(self._unsolvable_blockers.leaf_nodes())
		for node in myblocker_uninstalls.root_nodes():
			unsolvable_blockers.add(node)

		for blocker in unsolvable_blockers:
			retlist.append(blocker)

		# If any Uninstall tasks need to be executed in order
		# to avoid a conflict, complete the graph with any
		# dependencies that may have been initially
		# neglected (to ensure that unsafe Uninstall tasks
		# are properly identified and blocked from execution).
		if have_uninstall_task and \
			not complete and \
			not unsolvable_blockers:
			self.myparams.add("complete")
			raise self._serialize_tasks_retry("")

		if unsolvable_blockers and \
			not self._accept_blocker_conflicts():
			self._unsatisfied_blockers_for_display = unsolvable_blockers
			self._serialized_tasks_cache = retlist[:]
			self._scheduler_graph = scheduler_graph
			raise self._unknown_internal_error()

		if self._slot_collision_info and \
			not self._accept_blocker_conflicts():
			self._serialized_tasks_cache = retlist[:]
			self._scheduler_graph = scheduler_graph
			raise self._unknown_internal_error()

		return retlist, scheduler_graph

	def _show_circular_deps(self, mygraph):
		# No leaf nodes are available, so we have a circular
		# dependency panic situation.  Reduce the noise level to a
		# minimum via repeated elimination of root nodes since they
		# have no parents and thus can not be part of a cycle.
		while True:
			root_nodes = mygraph.root_nodes(
				ignore_priority=DepPrioritySatisfiedRange.ignore_medium_soft)
			if not root_nodes:
				break
			mygraph.difference_update(root_nodes)
		# Display the USE flags that are enabled on nodes that are part
		# of dependency cycles in case that helps the user decide to
		# disable some of them.
		display_order = []
		tempgraph = mygraph.copy()
		while not tempgraph.empty():
			nodes = tempgraph.leaf_nodes()
			if not nodes:
				node = tempgraph.order[0]
			else:
				node = nodes[0]
			display_order.append(node)
			tempgraph.remove(node)
		display_order.reverse()
		self.myopts.pop("--quiet", None)
		self.myopts.pop("--verbose", None)
		self.myopts["--tree"] = True
		portage.writemsg("\n\n", noiselevel=-1)
		self.display(display_order)
		prefix = colorize("BAD", " * ")
		portage.writemsg("\n", noiselevel=-1)
		portage.writemsg(prefix + "Error: circular dependencies:\n",
			noiselevel=-1)
		portage.writemsg("\n", noiselevel=-1)
		mygraph.debug_print()
		portage.writemsg("\n", noiselevel=-1)
		portage.writemsg(prefix + "Note that circular dependencies " + \
			"can often be avoided by temporarily\n", noiselevel=-1)
		portage.writemsg(prefix + "disabling USE flags that trigger " + \
			"optional dependencies.\n", noiselevel=-1)

	def _show_merge_list(self):
		if self._serialized_tasks_cache is not None and \
			not (self._displayed_list and \
			(self._displayed_list == self._serialized_tasks_cache or \
			self._displayed_list == \
				list(reversed(self._serialized_tasks_cache)))):
			display_list = self._serialized_tasks_cache[:]
			if "--tree" in self.myopts:
				display_list.reverse()
			self.display(display_list)

	def _show_unsatisfied_blockers(self, blockers):
		self._show_merge_list()
		msg = "Error: The above package list contains " + \
			"packages which cannot be installed " + \
			"at the same time on the same system."
		prefix = colorize("BAD", " * ")
		from textwrap import wrap
		portage.writemsg("\n", noiselevel=-1)
		for line in wrap(msg, 70):
			portage.writemsg(prefix + line + "\n", noiselevel=-1)

		# Display the conflicting packages along with the packages
		# that pulled them in. This is helpful for troubleshooting
		# cases in which blockers don't solve automatically and
		# the reasons are not apparent from the normal merge list
		# display.

		conflict_pkgs = {}
		for blocker in blockers:
			for pkg in chain(self._blocked_pkgs.child_nodes(blocker), \
				self._blocker_parents.parent_nodes(blocker)):
				parent_atoms = self._parent_atoms.get(pkg)
				if not parent_atoms:
					atom = self._blocked_world_pkgs.get(pkg)
					if atom is not None:
						parent_atoms = set([("@world", atom)])
				if parent_atoms:
					conflict_pkgs[pkg] = parent_atoms

		if conflict_pkgs:
			# Reduce noise by pruning packages that are only
			# pulled in by other conflict packages.
			pruned_pkgs = set()
			for pkg, parent_atoms in conflict_pkgs.iteritems():
				relevant_parent = False
				for parent, atom in parent_atoms:
					if parent not in conflict_pkgs:
						relevant_parent = True
						break
				if not relevant_parent:
					pruned_pkgs.add(pkg)
			for pkg in pruned_pkgs:
				del conflict_pkgs[pkg]

		if conflict_pkgs:
			msg = []
			msg.append("\n")
			indent = "  "
			# Max number of parents shown, to avoid flooding the display.
			max_parents = 3
			for pkg, parent_atoms in conflict_pkgs.iteritems():

				pruned_list = set()

				# Prefer packages that are not directly involved in a conflict.
				for parent_atom in parent_atoms:
					if len(pruned_list) >= max_parents:
						break
					parent, atom = parent_atom
					if parent not in conflict_pkgs:
						pruned_list.add(parent_atom)

				for parent_atom in parent_atoms:
					if len(pruned_list) >= max_parents:
						break
					pruned_list.add(parent_atom)

				omitted_parents = len(parent_atoms) - len(pruned_list)
				msg.append(indent + "%s pulled in by\n" % pkg)

				for parent_atom in pruned_list:
					parent, atom = parent_atom
					msg.append(2*indent)
					if isinstance(parent,
						(PackageArg, AtomArg)):
						# For PackageArg and AtomArg types, it's
						# redundant to display the atom attribute.
						msg.append(str(parent))
					else:
						# Display the specific atom from SetArg or
						# Package types.
						msg.append("%s required by %s" % (atom, parent))
					msg.append("\n")

				if omitted_parents:
					msg.append(2*indent)
					msg.append("(and %d more)\n" % omitted_parents)

				msg.append("\n")

			sys.stderr.write("".join(msg))
			sys.stderr.flush()

		if "--quiet" not in self.myopts:
			show_blocker_docs_link()

	def display(self, mylist, favorites=[], verbosity=None):

		# This is used to prevent display_problems() from
		# redundantly displaying this exact same merge list
		# again via _show_merge_list().
		self._displayed_list = mylist

		if verbosity is None:
			verbosity = ("--quiet" in self.myopts and 1 or \
				"--verbose" in self.myopts and 3 or 2)
		favorites_set = InternalPackageSet(favorites)
		oneshot = "--oneshot" in self.myopts or \
			"--onlydeps" in self.myopts
		columns = "--columns" in self.myopts
		changelogs=[]
		p=[]
		blockers = []

		counters = PackageCounters()

		if verbosity == 1 and "--verbose" not in self.myopts:
			def create_use_string(*args):
				return ""
		else:
			def create_use_string(name, cur_iuse, iuse_forced, cur_use,
				old_iuse, old_use,
				is_new, reinst_flags,
				all_flags=(verbosity == 3 or "--quiet" in self.myopts),
				alphabetical=("--alphabetical" in self.myopts)):
				enabled = []
				if alphabetical:
					disabled = enabled
					removed = enabled
				else:
					disabled = []
					removed = []
				cur_iuse = set(cur_iuse)
				enabled_flags = cur_iuse.intersection(cur_use)
				removed_iuse = set(old_iuse).difference(cur_iuse)
				any_iuse = cur_iuse.union(old_iuse)
				any_iuse = list(any_iuse)
				any_iuse.sort()
				for flag in any_iuse:
					flag_str = None
					isEnabled = False
					reinst_flag = reinst_flags and flag in reinst_flags
					if flag in enabled_flags:
						isEnabled = True
						if is_new or flag in old_use and \
							(all_flags or reinst_flag):
							flag_str = red(flag)
						elif flag not in old_iuse:
							flag_str = yellow(flag) + "%*"
						elif flag not in old_use:
							flag_str = green(flag) + "*"
					elif flag in removed_iuse:
						if all_flags or reinst_flag:
							flag_str = yellow("-" + flag) + "%"
							if flag in old_use:
								flag_str += "*"
							flag_str = "(" + flag_str + ")"
							removed.append(flag_str)
						continue
					else:
						if is_new or flag in old_iuse and \
							flag not in old_use and \
							(all_flags or reinst_flag):
							flag_str = blue("-" + flag)
						elif flag not in old_iuse:
							flag_str = yellow("-" + flag)
							if flag not in iuse_forced:
								flag_str += "%"
						elif flag in old_use:
							flag_str = green("-" + flag) + "*"
					if flag_str:
						if flag in iuse_forced:
							flag_str = "(" + flag_str + ")"
						if isEnabled:
							enabled.append(flag_str)
						else:
							disabled.append(flag_str)

				if alphabetical:
					ret = " ".join(enabled)
				else:
					ret = " ".join(enabled + disabled + removed)
				if ret:
					ret = '%s="%s" ' % (name, ret)
				return ret

		repo_display = RepoDisplay(self.roots)

		tree_nodes = []
		display_list = []
		mygraph = self.digraph.copy()

		# If there are any Uninstall instances, add the corresponding
		# blockers to the digraph (useful for --tree display).

		executed_uninstalls = set(node for node in mylist \
			if isinstance(node, Package) and node.operation == "unmerge")

		for uninstall in self._blocker_uninstalls.leaf_nodes():
			uninstall_parents = \
				self._blocker_uninstalls.parent_nodes(uninstall)
			if not uninstall_parents:
				continue

			# Remove the corresponding "nomerge" node and substitute
			# the Uninstall node.
			inst_pkg = self._pkg_cache[
				("installed", uninstall.root, uninstall.cpv, "nomerge")]
			try:
				mygraph.remove(inst_pkg)
			except KeyError:
				pass

			try:
				inst_pkg_blockers = self._blocker_parents.child_nodes(inst_pkg)
			except KeyError:
				inst_pkg_blockers = []

			# Break the Package -> Uninstall edges.
			mygraph.remove(uninstall)

			# Resolution of a package's blockers
			# depend on it's own uninstallation.
			for blocker in inst_pkg_blockers:
				mygraph.add(uninstall, blocker)

			# Expand Package -> Uninstall edges into
			# Package -> Blocker -> Uninstall edges.
			for blocker in uninstall_parents:
				mygraph.add(uninstall, blocker)
				for parent in self._blocker_parents.parent_nodes(blocker):
					if parent != inst_pkg:
						mygraph.add(blocker, parent)

			# If the uninstall task did not need to be executed because
			# of an upgrade, display Blocker -> Upgrade edges since the
			# corresponding Blocker -> Uninstall edges will not be shown.
			upgrade_node = \
				self._slot_pkg_map[uninstall.root].get(uninstall.slot_atom)
			if upgrade_node is not None and \
				uninstall not in executed_uninstalls:
				for blocker in uninstall_parents:
					mygraph.add(upgrade_node, blocker)

		unsatisfied_blockers = []
		i = 0
		depth = 0
		shown_edges = set()
		for x in mylist:
			if isinstance(x, Blocker) and not x.satisfied:
				unsatisfied_blockers.append(x)
				continue
			graph_key = x
			if "--tree" in self.myopts:
				depth = len(tree_nodes)
				while depth and graph_key not in \
					mygraph.child_nodes(tree_nodes[depth-1]):
						depth -= 1
				if depth:
					tree_nodes = tree_nodes[:depth]
					tree_nodes.append(graph_key)
					display_list.append((x, depth, True))
					shown_edges.add((graph_key, tree_nodes[depth-1]))
				else:
					traversed_nodes = set() # prevent endless circles
					traversed_nodes.add(graph_key)
					def add_parents(current_node, ordered):
						parent_nodes = None
						# Do not traverse to parents if this node is an
						# an argument or a direct member of a set that has
						# been specified as an argument (system or world).
						if current_node not in self._set_nodes:
							parent_nodes = mygraph.parent_nodes(current_node)
						if parent_nodes:
							child_nodes = set(mygraph.child_nodes(current_node))
							selected_parent = None
							# First, try to avoid a direct cycle.
							for node in parent_nodes:
								if not isinstance(node, (Blocker, Package)):
									continue
								if node not in traversed_nodes and \
									node not in child_nodes:
									edge = (current_node, node)
									if edge in shown_edges:
										continue
									selected_parent = node
									break
							if not selected_parent:
								# A direct cycle is unavoidable.
								for node in parent_nodes:
									if not isinstance(node, (Blocker, Package)):
										continue
									if node not in traversed_nodes:
										edge = (current_node, node)
										if edge in shown_edges:
											continue
										selected_parent = node
										break
							if selected_parent:
								shown_edges.add((current_node, selected_parent))
								traversed_nodes.add(selected_parent)
								add_parents(selected_parent, False)
						display_list.append((current_node,
							len(tree_nodes), ordered))
						tree_nodes.append(current_node)
					tree_nodes = []
					add_parents(graph_key, True)
			else:
				display_list.append((x, depth, True))
		mylist = display_list
		for x in unsatisfied_blockers:
			mylist.append((x, 0, True))

		last_merge_depth = 0
		for i in xrange(len(mylist)-1,-1,-1):
			graph_key, depth, ordered = mylist[i]
			if not ordered and depth == 0 and i > 0 \
				and graph_key == mylist[i-1][0] and \
				mylist[i-1][1] == 0:
				# An ordered node got a consecutive duplicate when the tree was
				# being filled in.
				del mylist[i]
				continue
			if ordered and graph_key[-1] != "nomerge":
				last_merge_depth = depth
				continue
			if depth >= last_merge_depth or \
				i < len(mylist) - 1 and \
				depth >= mylist[i+1][1]:
					del mylist[i]

		from portage import flatten
		from portage.dep import use_reduce, paren_reduce
		# files to fetch list - avoids counting a same file twice
		# in size display (verbose mode)
		myfetchlist=[]

		# Use this set to detect when all the "repoadd" strings are "[0]"
		# and disable the entire repo display in this case.
		repoadd_set = set()

		for mylist_index in xrange(len(mylist)):
			x, depth, ordered = mylist[mylist_index]
			pkg_type = x[0]
			myroot = x[1]
			pkg_key = x[2]
			portdb = self.trees[myroot]["porttree"].dbapi
			bindb  = self.trees[myroot]["bintree"].dbapi
			vardb = self.trees[myroot]["vartree"].dbapi
			vartree = self.trees[myroot]["vartree"]
			pkgsettings = self.pkgsettings[myroot]

			fetch=" "
			indent = " " * depth

			if isinstance(x, Blocker):
				if x.satisfied:
					blocker_style = "PKG_BLOCKER_SATISFIED"
					addl = "%s  %s  " % (colorize(blocker_style, "b"), fetch)
				else:
					blocker_style = "PKG_BLOCKER"
					addl = "%s  %s  " % (colorize(blocker_style, "B"), fetch)
				if ordered:
					counters.blocks += 1
					if x.satisfied:
						counters.blocks_satisfied += 1
				resolved = portage.key_expand(
					str(x.atom).lstrip("!"), mydb=vardb, settings=pkgsettings)
				if "--columns" in self.myopts and "--quiet" in self.myopts:
					addl += " " + colorize(blocker_style, resolved)
				else:
					addl = "[%s %s] %s%s" % \
						(colorize(blocker_style, "blocks"),
						addl, indent, colorize(blocker_style, resolved))
				block_parents = self._blocker_parents.parent_nodes(x)
				block_parents = set([pnode[2] for pnode in block_parents])
				block_parents = ", ".join(block_parents)
				if resolved!=x[2]:
					addl += colorize(blocker_style,
						" (\"%s\" is blocking %s)") % \
						(str(x.atom).lstrip("!"), block_parents)
				else:
					addl += colorize(blocker_style,
						" (is blocking %s)") % block_parents
				if isinstance(x, Blocker) and x.satisfied:
					if columns:
						continue
					p.append(addl)
				else:
					blockers.append(addl)
			else:
				pkg_status = x[3]
				pkg_merge = ordered and pkg_status == "merge"
				if not pkg_merge and pkg_status == "merge":
					pkg_status = "nomerge"
				built = pkg_type != "ebuild"
				installed = pkg_type == "installed"
				pkg = x
				metadata = pkg.metadata
				ebuild_path = None
				repo_name = metadata["repository"]
				if pkg_type == "ebuild":
					ebuild_path = portdb.findname(pkg_key)
					if not ebuild_path: # shouldn't happen
						raise portage.exception.PackageNotFound(pkg_key)
					repo_path_real = os.path.dirname(os.path.dirname(
						os.path.dirname(ebuild_path)))
				else:
					repo_path_real = portdb.getRepositoryPath(repo_name)
				pkg_use = list(pkg.use.enabled)
				try:
					restrict = flatten(use_reduce(paren_reduce(
						pkg.metadata["RESTRICT"]), uselist=pkg_use))
				except portage.exception.InvalidDependString, e:
					if not pkg.installed:
						show_invalid_depstring_notice(x,
							pkg.metadata["RESTRICT"], str(e))
						del e
						return 1
					restrict = []
				if "ebuild" == pkg_type and x[3] != "nomerge" and \
					"fetch" in restrict:
					fetch = red("F")
					if ordered:
						counters.restrict_fetch += 1
					if portdb.fetch_check(pkg_key, pkg_use):
						fetch = green("f")
						if ordered:
							counters.restrict_fetch_satisfied += 1

				#we need to use "--emptrytree" testing here rather than "empty" param testing because "empty"
				#param is used for -u, where you still *do* want to see when something is being upgraded.
				myoldbest = []
				myinslotlist = None
				installed_versions = vardb.match(portage.cpv_getkey(pkg_key))
				if vardb.cpv_exists(pkg_key):
					addl="  "+yellow("R")+fetch+"  "
					if ordered:
						if pkg_merge:
							counters.reinst += 1
						elif pkg_status == "uninstall":
							counters.uninst += 1
				# filter out old-style virtual matches
				elif installed_versions and \
					portage.cpv_getkey(installed_versions[0]) == \
					portage.cpv_getkey(pkg_key):
					myinslotlist = vardb.match(pkg.slot_atom)
					# If this is the first install of a new-style virtual, we
					# need to filter out old-style virtual matches.
					if myinslotlist and \
						portage.cpv_getkey(myinslotlist[0]) != \
						portage.cpv_getkey(pkg_key):
						myinslotlist = None
					if myinslotlist:
						myoldbest = myinslotlist[:]
						addl = "   " + fetch
						if not portage.dep.cpvequal(pkg_key,
							portage.best([pkg_key] + myoldbest)):
							# Downgrade in slot
							addl += turquoise("U")+blue("D")
							if ordered:
								counters.downgrades += 1
						else:
							# Update in slot
							addl += turquoise("U") + " "
							if ordered:
								counters.upgrades += 1
					else:
						# New slot, mark it new.
						addl = " " + green("NS") + fetch + "  "
						myoldbest = vardb.match(portage.cpv_getkey(pkg_key))
						if ordered:
							counters.newslot += 1

					if "--changelog" in self.myopts:
						inst_matches = vardb.match(pkg.slot_atom)
						if inst_matches:
							changelogs.extend(self.calc_changelog(
								portdb.findname(pkg_key),
								inst_matches[0], pkg_key))
				else:
					addl = " " + green("N") + " " + fetch + "  "
					if ordered:
						counters.new += 1

				verboseadd = ""
				repoadd = None

				if True:
					# USE flag display
					forced_flags = set()
					pkgsettings.setcpv(pkg) # for package.use.{mask,force}
					forced_flags.update(pkgsettings.useforce)
					forced_flags.update(pkgsettings.usemask)

					cur_use = [flag for flag in pkg.use.enabled \
						if flag in pkg.iuse.all]
					cur_iuse = sorted(pkg.iuse.all)

					if myoldbest and myinslotlist:
						previous_cpv = myoldbest[0]
					else:
						previous_cpv = pkg.cpv
					if vardb.cpv_exists(previous_cpv):
						old_iuse, old_use = vardb.aux_get(
								previous_cpv, ["IUSE", "USE"])
						old_iuse = list(set(
							filter_iuse_defaults(old_iuse.split())))
						old_iuse.sort()
						old_use = old_use.split()
						is_new = False
					else:
						old_iuse = []
						old_use = []
						is_new = True

					old_use = [flag for flag in old_use if flag in old_iuse]

					use_expand = pkgsettings["USE_EXPAND"].lower().split()
					use_expand.sort()
					use_expand.reverse()
					use_expand_hidden = \
						pkgsettings["USE_EXPAND_HIDDEN"].lower().split()

					def map_to_use_expand(myvals, forcedFlags=False,
						removeHidden=True):
						ret = {}
						forced = {}
						for exp in use_expand:
							ret[exp] = []
							forced[exp] = set()
							for val in myvals[:]:
								if val.startswith(exp.lower()+"_"):
									if val in forced_flags:
										forced[exp].add(val[len(exp)+1:])
									ret[exp].append(val[len(exp)+1:])
									myvals.remove(val)
						ret["USE"] = myvals
						forced["USE"] = [val for val in myvals \
							if val in forced_flags]
						if removeHidden:
							for exp in use_expand_hidden:
								ret.pop(exp, None)
						if forcedFlags:
							return ret, forced
						return ret

					# Prevent USE_EXPAND_HIDDEN flags from being hidden if they
					# are the only thing that triggered reinstallation.
					reinst_flags_map = {}
					reinstall_for_flags = self._reinstall_nodes.get(pkg)
					reinst_expand_map = None
					if reinstall_for_flags:
						reinst_flags_map = map_to_use_expand(
							list(reinstall_for_flags), removeHidden=False)
						for k in list(reinst_flags_map):
							if not reinst_flags_map[k]:
								del reinst_flags_map[k]
						if not reinst_flags_map.get("USE"):
							reinst_expand_map = reinst_flags_map.copy()
							reinst_expand_map.pop("USE", None)
					if reinst_expand_map and \
						not set(reinst_expand_map).difference(
						use_expand_hidden):
						use_expand_hidden = \
							set(use_expand_hidden).difference(
							reinst_expand_map)

					cur_iuse_map, iuse_forced = \
						map_to_use_expand(cur_iuse, forcedFlags=True)
					cur_use_map = map_to_use_expand(cur_use)
					old_iuse_map = map_to_use_expand(old_iuse)
					old_use_map = map_to_use_expand(old_use)

					use_expand.sort()
					use_expand.insert(0, "USE")
					
					for key in use_expand:
						if key in use_expand_hidden:
							continue
						verboseadd += create_use_string(key.upper(),
							cur_iuse_map[key], iuse_forced[key],
							cur_use_map[key], old_iuse_map[key],
							old_use_map[key], is_new,
							reinst_flags_map.get(key))

				if verbosity == 3:
					# size verbose
					mysize=0
					if pkg_type == "ebuild" and pkg_merge:
						try:
							myfilesdict = portdb.getfetchsizes(pkg_key,
								useflags=pkg_use, debug=self.edebug)
						except portage.exception.InvalidDependString, e:
							src_uri = portdb.aux_get(pkg_key, ["SRC_URI"])[0]
							show_invalid_depstring_notice(x, src_uri, str(e))
							del e
							return 1
						if myfilesdict is None:
							myfilesdict="[empty/missing/bad digest]"
						else:
							for myfetchfile in myfilesdict:
								if myfetchfile not in myfetchlist:
									mysize+=myfilesdict[myfetchfile]
									myfetchlist.append(myfetchfile)
							if ordered:
								counters.totalsize += mysize
						verboseadd += format_size(mysize)

					# overlay verbose
					# assign index for a previous version in the same slot
					has_previous = False
					repo_name_prev = None
					slot_atom = "%s:%s" % (portage.dep_getkey(pkg_key),
						metadata["SLOT"])
					slot_matches = vardb.match(slot_atom)
					if slot_matches:
						has_previous = True
						repo_name_prev = vardb.aux_get(slot_matches[0],
							["repository"])[0]

					# now use the data to generate output
					if pkg.installed or not has_previous:
						repoadd = repo_display.repoStr(repo_path_real)
					else:
						repo_path_prev = None
						if repo_name_prev:
							repo_path_prev = portdb.getRepositoryPath(
								repo_name_prev)
						if repo_path_prev == repo_path_real:
							repoadd = repo_display.repoStr(repo_path_real)
						else:
							repoadd = "%s=>%s" % (
								repo_display.repoStr(repo_path_prev),
								repo_display.repoStr(repo_path_real))
					if repoadd:
						repoadd_set.add(repoadd)

				xs = [portage.cpv_getkey(pkg_key)] + \
					list(portage.catpkgsplit(pkg_key)[2:])
				if xs[2] == "r0":
					xs[2] = ""
				else:
					xs[2] = "-" + xs[2]

				mywidth = 130
				if "COLUMNWIDTH" in self.settings:
					try:
						mywidth = int(self.settings["COLUMNWIDTH"])
					except ValueError, e:
						portage.writemsg("!!! %s\n" % str(e), noiselevel=-1)
						portage.writemsg(
							"!!! Unable to parse COLUMNWIDTH='%s'\n" % \
							self.settings["COLUMNWIDTH"], noiselevel=-1)
						del e
				oldlp = mywidth - 30
				newlp = oldlp - 30

				# Convert myoldbest from a list to a string.
				if not myoldbest:
					myoldbest = ""
				else:
					for pos, key in enumerate(myoldbest):
						key = portage.catpkgsplit(key)[2] + \
							"-" + portage.catpkgsplit(key)[3]
						if key[-3:] == "-r0":
							key = key[:-3]
						myoldbest[pos] = key
					myoldbest = blue("["+", ".join(myoldbest)+"]")

				pkg_cp = xs[0]
				root_config = self.roots[myroot]
				system_set = root_config.sets["system"]
				world_set  = root_config.sets["world"]

				pkg_system = False
				pkg_world = False
				try:
					pkg_system = system_set.findAtomForPackage(pkg)
					pkg_world  = world_set.findAtomForPackage(pkg)
					if not (oneshot or pkg_world) and \
						myroot == self.target_root and \
						favorites_set.findAtomForPackage(pkg):
						# Maybe it will be added to world now.
						if create_world_atom(pkg, favorites_set, root_config):
							pkg_world = True
				except portage.exception.InvalidDependString:
					# This is reported elsewhere if relevant.
					pass

				def pkgprint(pkg_str):
					if pkg_merge:
						if pkg_system:
							return colorize("PKG_MERGE_SYSTEM", pkg_str)
						elif pkg_world:
							return colorize("PKG_MERGE_WORLD", pkg_str)
						else:
							return colorize("PKG_MERGE", pkg_str)
					elif pkg_status == "uninstall":
						return colorize("PKG_UNINSTALL", pkg_str)
					else:
						if pkg_system:
							return colorize("PKG_NOMERGE_SYSTEM", pkg_str)
						elif pkg_world:
							return colorize("PKG_NOMERGE_WORLD", pkg_str)
						else:
							return colorize("PKG_NOMERGE", pkg_str)

				try:
					properties = flatten(use_reduce(paren_reduce(
						pkg.metadata["PROPERTIES"]), uselist=pkg.use.enabled))
				except portage.exception.InvalidDependString, e:
					if not pkg.installed:
						show_invalid_depstring_notice(pkg,
							pkg.metadata["PROPERTIES"], str(e))
						del e
						return 1
					properties = []
				interactive = "interactive" in properties
				if interactive and pkg.operation == "merge":
					addl = colorize("WARN", "I") + addl[1:]
					if ordered:
						counters.interactive += 1

				if x[1]!="/":
					if myoldbest:
						myoldbest +=" "
					if "--columns" in self.myopts:
						if "--quiet" in self.myopts:
							myprint=addl+" "+indent+pkgprint(pkg_cp)
							myprint=myprint+darkblue(" "+xs[1]+xs[2])+" "
							myprint=myprint+myoldbest
							myprint=myprint+darkgreen("to "+x[1])
							verboseadd = None
						else:
							if not pkg_merge:
								myprint = "[%s] %s%s" % \
									(pkgprint(pkg_status.ljust(13)),
									indent, pkgprint(pkg.cp))
							else:
								myprint = "[%s %s] %s%s" % \
									(pkgprint(pkg.type_name), addl,
									indent, pkgprint(pkg.cp))
							if (newlp-nc_len(myprint)) > 0:
								myprint=myprint+(" "*(newlp-nc_len(myprint)))
							myprint=myprint+"["+darkblue(xs[1]+xs[2])+"] "
							if (oldlp-nc_len(myprint)) > 0:
								myprint=myprint+" "*(oldlp-nc_len(myprint))
							myprint=myprint+myoldbest
							myprint += darkgreen("to " + pkg.root)
					else:
						if not pkg_merge:
							myprint = "[%s] " % pkgprint(pkg_status.ljust(13))
						else:
							myprint = "[%s %s] " % (pkgprint(pkg_type), addl)
						myprint += indent + pkgprint(pkg_key) + " " + \
							myoldbest + darkgreen("to " + myroot)
				else:
					if "--columns" in self.myopts:
						if "--quiet" in self.myopts:
							myprint=addl+" "+indent+pkgprint(pkg_cp)
							myprint=myprint+" "+green(xs[1]+xs[2])+" "
							myprint=myprint+myoldbest
							verboseadd = None
						else:
							if not pkg_merge:
								myprint = "[%s] %s%s" % \
									(pkgprint(pkg_status.ljust(13)),
									indent, pkgprint(pkg.cp))
							else:
								myprint = "[%s %s] %s%s" % \
									(pkgprint(pkg.type_name), addl,
									indent, pkgprint(pkg.cp))
							if (newlp-nc_len(myprint)) > 0:
								myprint=myprint+(" "*(newlp-nc_len(myprint)))
							myprint=myprint+green(" ["+xs[1]+xs[2]+"] ")
							if (oldlp-nc_len(myprint)) > 0:
								myprint=myprint+(" "*(oldlp-nc_len(myprint)))
							myprint += myoldbest
					else:
						if not pkg_merge:
							myprint = "[%s] %s%s %s" % \
								(pkgprint(pkg_status.ljust(13)),
								indent, pkgprint(pkg.cpv),
								myoldbest)
						else:
							myprint = "[%s %s] %s%s %s" % \
								(pkgprint(pkg_type), addl, indent,
								pkgprint(pkg.cpv), myoldbest)

				if columns and pkg.operation == "uninstall":
					continue
				p.append((myprint, verboseadd, repoadd))

				if "--tree" not in self.myopts and \
					"--quiet" not in self.myopts and \
					not self._opts_no_restart.intersection(self.myopts) and \
					pkg.root == self._running_root.root and \
					portage.match_from_list(
					portage.const.PORTAGE_PACKAGE_ATOM, [pkg]) and \
					not vardb.cpv_exists(pkg.cpv) and \
					"--quiet" not in self.myopts:
						if mylist_index < len(mylist) - 1:
							p.append(colorize("WARN", "*** Portage will stop merging at this point and reload itself,"))
							p.append(colorize("WARN", "    then resume the merge."))

		out = sys.stdout
		show_repos = repoadd_set and repoadd_set != set(["0"])

		for x in p:
			if isinstance(x, basestring):
				out.write("%s\n" % (x,))
				continue

			myprint, verboseadd, repoadd = x

			if verboseadd:
				myprint += " " + verboseadd

			if show_repos and repoadd:
				myprint += " " + teal("[%s]" % repoadd)

			out.write("%s\n" % (myprint,))

		for x in blockers:
			print x

		if verbosity == 3:
			print
			print counters
			if show_repos:
				sys.stdout.write(str(repo_display))

		if "--changelog" in self.myopts:
			print
			for revision,text in changelogs:
				print bold('*'+revision)
				sys.stdout.write(text)

		sys.stdout.flush()
		return os.EX_OK

	def display_problems(self):
		"""
		Display problems with the dependency graph such as slot collisions.
		This is called internally by display() to show the problems _after_
		the merge list where it is most likely to be seen, but if display()
		is not going to be called then this method should be called explicitly
		to ensure that the user is notified of problems with the graph.

		All output goes to stderr, except for unsatisfied dependencies which
		go to stdout for parsing by programs such as autounmask.
		"""

		# Note that show_masked_packages() sends it's output to
		# stdout, and some programs such as autounmask parse the
		# output in cases when emerge bails out. However, when
		# show_masked_packages() is called for installed packages
		# here, the message is a warning that is more appropriate
		# to send to stderr, so temporarily redirect stdout to
		# stderr. TODO: Fix output code so there's a cleaner way
		# to redirect everything to stderr.
		sys.stdout.flush()
		sys.stderr.flush()
		stdout = sys.stdout
		try:
			sys.stdout = sys.stderr
			self._display_problems()
		finally:
			sys.stdout = stdout
			sys.stdout.flush()
			sys.stderr.flush()

		# This goes to stdout for parsing by programs like autounmask.
		for pargs, kwargs in self._unsatisfied_deps_for_display:
			self._show_unsatisfied_dep(*pargs, **kwargs)

	def _display_problems(self):
		if self._circular_deps_for_display is not None:
			self._show_circular_deps(
				self._circular_deps_for_display)

		# The user is only notified of a slot conflict if
		# there are no unresolvable blocker conflicts.
		if self._unsatisfied_blockers_for_display is not None:
			self._show_unsatisfied_blockers(
				self._unsatisfied_blockers_for_display)
		else:
			self._show_slot_collision_notice()

		# TODO: Add generic support for "set problem" handlers so that
		# the below warnings aren't special cases for world only.

		if self._missing_args:
			world_problems = False
			if "world" in self._sets:
				# Filter out indirect members of world (from nested sets)
				# since only direct members of world are desired here.
				world_set = self.roots[self.target_root].sets["world"]
				for arg, atom in self._missing_args:
					if arg.name == "world" and atom in world_set:
						world_problems = True
						break

			if world_problems:
				sys.stderr.write("\n!!! Problems have been " + \
					"detected with your world file\n")
				sys.stderr.write("!!! Please run " + \
					green("emaint --check world")+"\n\n")

		if self._missing_args:
			sys.stderr.write("\n" + colorize("BAD", "!!!") + \
				" Ebuilds for the following packages are either all\n")
			sys.stderr.write(colorize("BAD", "!!!") + \
				" masked or don't exist:\n")
			sys.stderr.write(" ".join(str(atom) for arg, atom in \
				self._missing_args) + "\n")

		if self._pprovided_args:
			arg_refs = {}
			for arg, atom in self._pprovided_args:
				if isinstance(arg, SetArg):
					parent = arg.name
					arg_atom = (atom, atom)
				else:
					parent = "args"
					arg_atom = (arg.arg, atom)
				refs = arg_refs.setdefault(arg_atom, [])
				if parent not in refs:
					refs.append(parent)
			msg = []
			msg.append(bad("\nWARNING: "))
			if len(self._pprovided_args) > 1:
				msg.append("Requested packages will not be " + \
					"merged because they are listed in\n")
			else:
				msg.append("A requested package will not be " + \
					"merged because it is listed in\n")
			msg.append("package.provided:\n\n")
			problems_sets = set()
			for (arg, atom), refs in arg_refs.iteritems():
				ref_string = ""
				if refs:
					problems_sets.update(refs)
					refs.sort()
					ref_string = ", ".join(["'%s'" % name for name in refs])
					ref_string = " pulled in by " + ref_string
				msg.append("  %s%s\n" % (colorize("INFORM", str(arg)), ref_string))
			msg.append("\n")
			if "world" in problems_sets:
				msg.append("This problem can be solved in one of the following ways:\n\n")
				msg.append("  A) Use emaint to clean offending packages from world (if not installed).\n")
				msg.append("  B) Uninstall offending packages (cleans them from world).\n")
				msg.append("  C) Remove offending entries from package.provided.\n\n")
				msg.append("The best course of action depends on the reason that an offending\n")
				msg.append("package.provided entry exists.\n\n")
			sys.stderr.write("".join(msg))

		masked_packages = []
		for pkg in self._masked_installed:
			root_config = pkg.root_config
			pkgsettings = self.pkgsettings[pkg.root]
			mreasons = get_masking_status(pkg, pkgsettings, root_config)
			masked_packages.append((root_config, pkgsettings,
				pkg.cpv, pkg.metadata, mreasons))
		if masked_packages:
			sys.stderr.write("\n" + colorize("BAD", "!!!") + \
				" The following installed packages are masked:\n")
			show_masked_packages(masked_packages)
			show_mask_docs()
			print

	def calc_changelog(self,ebuildpath,current,next):
		if ebuildpath == None or not os.path.exists(ebuildpath):
			return []
		current = '-'.join(portage.catpkgsplit(current)[1:])
		if current.endswith('-r0'):
			current = current[:-3]
		next = '-'.join(portage.catpkgsplit(next)[1:])
		if next.endswith('-r0'):
			next = next[:-3]
		changelogpath = os.path.join(os.path.split(ebuildpath)[0],'ChangeLog')
		try:
			changelog = open(changelogpath).read()
		except SystemExit, e:
			raise # Needed else can't exit
		except:
			return []
		divisions = self.find_changelog_tags(changelog)
		#print 'XX from',current,'to',next
		#for div,text in divisions: print 'XX',div
		# skip entries for all revisions above the one we are about to emerge
		for i in range(len(divisions)):
			if divisions[i][0]==next:
				divisions = divisions[i:]
				break
		# find out how many entries we are going to display
		for i in range(len(divisions)):
			if divisions[i][0]==current:
				divisions = divisions[:i]
				break
		else:
		    # couldnt find the current revision in the list. display nothing
			return []
		return divisions

	def find_changelog_tags(self,changelog):
		divs = []
		release = None
		while 1:
			match = re.search(r'^\*\ ?([-a-zA-Z0-9_.+]*)(?:\ .*)?\n',changelog,re.M)
			if match is None:
				if release is not None:
					divs.append((release,changelog))
				return divs
			if release is not None:
				divs.append((release,changelog[:match.start()]))
			changelog = changelog[match.end():]
			release = match.group(1)
			if release.endswith('.ebuild'):
				release = release[:-7]
			if release.endswith('-r0'):
				release = release[:-3]

	def saveNomergeFavorites(self):
		"""Find atoms in favorites that are not in the mergelist and add them
		to the world file if necessary."""
		for x in ("--buildpkgonly", "--fetchonly", "--fetch-all-uri",
			"--oneshot", "--onlydeps", "--pretend"):
			if x in self.myopts:
				return
		root_config = self.roots[self.target_root]
		world_set = root_config.sets["world"]

		world_locked = False
		if hasattr(world_set, "lock"):
			world_set.lock()
			world_locked = True

		if hasattr(world_set, "load"):
			world_set.load() # maybe it's changed on disk

		args_set = self._sets["args"]
		portdb = self.trees[self.target_root]["porttree"].dbapi
		added_favorites = set()
		for x in self._set_nodes:
			pkg_type, root, pkg_key, pkg_status = x
			if pkg_status != "nomerge":
				continue

			try:
				myfavkey = create_world_atom(x, args_set, root_config)
				if myfavkey:
					if myfavkey in added_favorites:
						continue
					added_favorites.add(myfavkey)
			except portage.exception.InvalidDependString, e:
				writemsg("\n\n!!! '%s' has invalid PROVIDE: %s\n" % \
					(pkg_key, str(e)), noiselevel=-1)
				writemsg("!!! see '%s'\n\n" % os.path.join(
					root, portage.VDB_PATH, pkg_key, "PROVIDE"), noiselevel=-1)
				del e
		all_added = []
		for k in self._sets:
			if k in ("args", "world") or not root_config.sets[k].world_candidate:
				continue
			s = SETPREFIX + k
			if s in world_set:
				continue
			all_added.append(SETPREFIX + k)
		all_added.extend(added_favorites)
		all_added.sort()
		for a in all_added:
			print ">>> Recording %s in \"world\" favorites file..." % \
				colorize("INFORM", str(a))
		if all_added:
			world_set.update(all_added)

		if world_locked:
			world_set.unlock()

	def loadResumeCommand(self, resume_data, skip_masked=False):
		"""
		Add a resume command to the graph and validate it in the process.  This
		will raise a PackageNotFound exception if a package is not available.
		"""

		if not isinstance(resume_data, dict):
			return False

		mergelist = resume_data.get("mergelist")
		if not isinstance(mergelist, list):
			mergelist = []

		fakedb = self.mydbapi
		trees = self.trees
		serialized_tasks = []
		masked_tasks = []
		for x in mergelist:
			if not (isinstance(x, list) and len(x) == 4):
				continue
			pkg_type, myroot, pkg_key, action = x
			if pkg_type not in self.pkg_tree_map:
				continue
			if action != "merge":
				continue
			tree_type = self.pkg_tree_map[pkg_type]
			mydb = trees[myroot][tree_type].dbapi
			db_keys = list(self._trees_orig[myroot][
				tree_type].dbapi._aux_cache_keys)
			try:
				metadata = izip(db_keys, mydb.aux_get(pkg_key, db_keys))
			except KeyError:
				# It does no exist or it is corrupt.
				if action == "uninstall":
					continue
				raise portage.exception.PackageNotFound(pkg_key)
			installed = action == "uninstall"
			built = pkg_type != "ebuild"
			root_config = self.roots[myroot]
			pkg = Package(built=built, cpv=pkg_key,
				installed=installed, metadata=metadata,
				operation=action, root_config=root_config,
				type_name=pkg_type)
			if pkg_type == "ebuild":
				pkgsettings = self.pkgsettings[myroot]
				pkgsettings.setcpv(pkg)
				pkg.metadata["USE"] = pkgsettings["PORTAGE_USE"]
				pkg.metadata['CHOST'] = pkgsettings.get('CHOST', '')
			self._pkg_cache[pkg] = pkg

			root_config = self.roots[pkg.root]
			if "merge" == pkg.operation and \
				not visible(root_config.settings, pkg):
				if skip_masked:
					masked_tasks.append(Dependency(root=pkg.root, parent=pkg))
				else:
					self._unsatisfied_deps_for_display.append(
						((pkg.root, "="+pkg.cpv), {"myparent":None}))

			fakedb[myroot].cpv_inject(pkg)
			serialized_tasks.append(pkg)
			self.spinner.update()

		if self._unsatisfied_deps_for_display:
			return False

		if not serialized_tasks or "--nodeps" in self.myopts:
			self._serialized_tasks_cache = serialized_tasks
			self._scheduler_graph = self.digraph
		else:
			self._select_package = self._select_pkg_from_graph
			self.myparams.add("selective")
			# Always traverse deep dependencies in order to account for
			# potentially unsatisfied dependencies of installed packages.
			# This is necessary for correct --keep-going or --resume operation
			# in case a package from a group of circularly dependent packages
			# fails. In this case, a package which has recently been installed
			# may have an unsatisfied circular dependency (pulled in by
			# PDEPEND, for example). So, even though a package is already
			# installed, it may not have all of it's dependencies satisfied, so
			# it may not be usable. If such a package is in the subgraph of
			# deep depenedencies of a scheduled build, that build needs to
			# be cancelled. In order for this type of situation to be
			# recognized, deep traversal of dependencies is required.
			self.myparams.add("deep")

			favorites = resume_data.get("favorites")
			args_set = self._sets["args"]
			if isinstance(favorites, list):
				args = self._load_favorites(favorites)
			else:
				args = []

			for task in serialized_tasks:
				if isinstance(task, Package) and \
					task.operation == "merge":
					if not self._add_pkg(task, None):
						return False

			# Packages for argument atoms need to be explicitly
			# added via _add_pkg() so that they are included in the
			# digraph (needed at least for --tree display).
			for arg in args:
				for atom in arg.set:
					pkg, existing_node = self._select_package(
						arg.root_config.root, atom)
					if existing_node is None and \
						pkg is not None:
						if not self._add_pkg(pkg, Dependency(atom=atom,
							root=pkg.root, parent=arg)):
							return False

			# Allow unsatisfied deps here to avoid showing a masking
			# message for an unsatisfied dep that isn't necessarily
			# masked.
			if not self._create_graph(allow_unsatisfied=True):
				return False

			unsatisfied_deps = []
			for dep in self._unsatisfied_deps:
				if not isinstance(dep.parent, Package):
					continue
				if dep.parent.operation == "merge":
					unsatisfied_deps.append(dep)
					continue

				# For unsatisfied deps of installed packages, only account for
				# them if they are in the subgraph of dependencies of a package
				# which is scheduled to be installed.
				unsatisfied_install = False
				traversed = set()
				dep_stack = self.digraph.parent_nodes(dep.parent)
				while dep_stack:
					node = dep_stack.pop()
					if not isinstance(node, Package):
						continue
					if node.operation == "merge":
						unsatisfied_install = True
						break
					if node in traversed:
						continue
					traversed.add(node)
					dep_stack.extend(self.digraph.parent_nodes(node))

				if unsatisfied_install:
					unsatisfied_deps.append(dep)

			if masked_tasks or unsatisfied_deps:
				# This probably means that a required package
				# was dropped via --skipfirst. It makes the
				# resume list invalid, so convert it to a
				# UnsatisfiedResumeDep exception.
				raise self.UnsatisfiedResumeDep(self,
					masked_tasks + unsatisfied_deps)
			self._serialized_tasks_cache = None
			try:
				self.altlist()
			except self._unknown_internal_error:
				return False

		return True

	def _load_favorites(self, favorites):
		"""
		Use a list of favorites to resume state from a
		previous select_files() call. This creates similar
		DependencyArg instances to those that would have
		been created by the original select_files() call.
		This allows Package instances to be matched with
		DependencyArg instances during graph creation.
		"""
		root_config = self.roots[self.target_root]
		getSetAtoms = root_config.setconfig.getSetAtoms
		sets = root_config.sets
		args = []
		for x in favorites:
			if not isinstance(x, basestring):
				continue
			if x in ("system", "world"):
				x = SETPREFIX + x
			if x.startswith(SETPREFIX):
				s = x[len(SETPREFIX):]
				if s not in sets:
					continue
				if s in self._sets:
					continue
				# Recursively expand sets so that containment tests in
				# self._get_parent_sets() properly match atoms in nested
				# sets (like if world contains system).
				expanded_set = InternalPackageSet(
					initial_atoms=getSetAtoms(s))
				self._sets[s] = expanded_set
				args.append(SetArg(arg=x, set=expanded_set,
					root_config=root_config))
			else:
				if not portage.isvalidatom(x):
					continue
				args.append(AtomArg(arg=x, atom=x,
					root_config=root_config))

		self._set_args(args)
		return args

	class UnsatisfiedResumeDep(portage.exception.PortageException):
		"""
		A dependency of a resume list is not installed. This
		can occur when a required package is dropped from the
		merge list via --skipfirst.
		"""
		def __init__(self, depgraph, value):
			portage.exception.PortageException.__init__(self, value)
			self.depgraph = depgraph

	class _internal_exception(portage.exception.PortageException):
		def __init__(self, value=""):
			portage.exception.PortageException.__init__(self, value)

	class _unknown_internal_error(_internal_exception):
		"""
		Used by the depgraph internally to terminate graph creation.
		The specific reason for the failure should have been dumped
		to stderr, unfortunately, the exact reason for the failure
		may not be known.
		"""

	class _serialize_tasks_retry(_internal_exception):
		"""
		This is raised by the _serialize_tasks() method when it needs to
		be called again for some reason. The only case that it's currently
		used for is when neglected dependencies need to be added to the
		graph in order to avoid making a potentially unsafe decision.
		"""

	class _dep_check_composite_db(portage.dbapi):
		"""
		A dbapi-like interface that is optimized for use in dep_check() calls.
		This is built on top of the existing depgraph package selection logic.
		Some packages that have been added to the graph may be masked from this
		view in order to influence the atom preference selection that occurs
		via dep_check().
		"""
		def __init__(self, depgraph, root):
			portage.dbapi.__init__(self)
			self._depgraph = depgraph
			self._root = root
			self._match_cache = {}
			self._cpv_pkg_map = {}

		def _clear_cache(self):
			self._match_cache.clear()
			self._cpv_pkg_map.clear()

		def match(self, atom):
			ret = self._match_cache.get(atom)
			if ret is not None:
				return ret[:]
			orig_atom = atom
			if "/" not in atom:
				atom = self._dep_expand(atom)
			pkg, existing = self._depgraph._select_package(self._root, atom)
			if not pkg:
				ret = []
			else:
				# Return the highest available from select_package() as well as
				# any matching slots in the graph db.
				slots = set()
				slots.add(pkg.metadata["SLOT"])
				atom_cp = portage.dep_getkey(atom)
				if pkg.cp.startswith("virtual/"):
					# For new-style virtual lookahead that occurs inside
					# dep_check(), examine all slots. This is needed
					# so that newer slots will not unnecessarily be pulled in
					# when a satisfying lower slot is already installed. For
					# example, if virtual/jdk-1.4 is satisfied via kaffe then
					# there's no need to pull in a newer slot to satisfy a
					# virtual/jdk dependency.
					for db, pkg_type, built, installed, db_keys in \
						self._depgraph._filtered_trees[self._root]["dbs"]:
						for cpv in db.match(atom):
							if portage.cpv_getkey(cpv) != pkg.cp:
								continue
							slots.add(db.aux_get(cpv, ["SLOT"])[0])
				ret = []
				if self._visible(pkg):
					self._cpv_pkg_map[pkg.cpv] = pkg
					ret.append(pkg.cpv)
				slots.remove(pkg.metadata["SLOT"])
				while slots:
					slot_atom = "%s:%s" % (atom_cp, slots.pop())
					pkg, existing = self._depgraph._select_package(
						self._root, slot_atom)
					if not pkg:
						continue
					if not self._visible(pkg):
						continue
					self._cpv_pkg_map[pkg.cpv] = pkg
					ret.append(pkg.cpv)
				if ret:
					self._cpv_sort_ascending(ret)
			self._match_cache[orig_atom] = ret
			return ret[:]

		def _visible(self, pkg):
			if pkg.installed and "selective" not in self._depgraph.myparams:
				try:
					arg = self._depgraph._iter_atoms_for_pkg(pkg).next()
				except (StopIteration, portage.exception.InvalidDependString):
					arg = None
				if arg:
					return False
			if pkg.installed:
				try:
					if not visible(
						self._depgraph.pkgsettings[pkg.root], pkg):
						return False
				except portage.exception.InvalidDependString:
					pass
			in_graph = self._depgraph._slot_pkg_map[
				self._root].get(pkg.slot_atom)
			if in_graph is None:
				# Mask choices for packages which are not the highest visible
				# version within their slot (since they usually trigger slot
				# conflicts).
				highest_visible, in_graph = self._depgraph._select_package(
					self._root, pkg.slot_atom)
				if pkg != highest_visible:
					return False
			elif in_graph != pkg:
				# Mask choices for packages that would trigger a slot
				# conflict with a previously selected package.
				return False
			return True

		def _dep_expand(self, atom):
			"""
			This is only needed for old installed packages that may
			contain atoms that are not fully qualified with a specific
			category. Emulate the cpv_expand() function that's used by
			dbapi.match() in cases like this. If there are multiple
			matches, it's often due to a new-style virtual that has
			been added, so try to filter those out to avoid raising
			a ValueError.
			"""
			root_config = self._depgraph.roots[self._root]
			orig_atom = atom
			expanded_atoms = self._depgraph._dep_expand(root_config, atom)
			if len(expanded_atoms) > 1:
				non_virtual_atoms = []
				for x in expanded_atoms:
					if not portage.dep_getkey(x).startswith("virtual/"):
						non_virtual_atoms.append(x)
				if len(non_virtual_atoms) == 1:
					expanded_atoms = non_virtual_atoms
			if len(expanded_atoms) > 1:
				# compatible with portage.cpv_expand()
				raise portage.exception.AmbiguousPackageName(
					[portage.dep_getkey(x) for x in expanded_atoms])
			if expanded_atoms:
				atom = expanded_atoms[0]
			else:
				null_atom = insert_category_into_atom(atom, "null")
				null_cp = portage.dep_getkey(null_atom)
				cat, atom_pn = portage.catsplit(null_cp)
				virts_p = root_config.settings.get_virts_p().get(atom_pn)
				if virts_p:
					# Allow the resolver to choose which virtual.
					atom = insert_category_into_atom(atom, "virtual")
				else:
					atom = insert_category_into_atom(atom, "null")
			return atom

		def aux_get(self, cpv, wants):
			metadata = self._cpv_pkg_map[cpv].metadata
			return [metadata.get(x, "") for x in wants]

class RepoDisplay(object):
	def __init__(self, roots):
		self._shown_repos = {}
		self._unknown_repo = False
		repo_paths = set()
		for root_config in roots.itervalues():
			portdir = root_config.settings.get("PORTDIR")
			if portdir:
				repo_paths.add(portdir)
			overlays = root_config.settings.get("PORTDIR_OVERLAY")
			if overlays:
				repo_paths.update(overlays.split())
		repo_paths = list(repo_paths)
		self._repo_paths = repo_paths
		self._repo_paths_real = [ os.path.realpath(repo_path) \
			for repo_path in repo_paths ]

		# pre-allocate index for PORTDIR so that it always has index 0.
		for root_config in roots.itervalues():
			portdb = root_config.trees["porttree"].dbapi
			portdir = portdb.porttree_root
			if portdir:
				self.repoStr(portdir)

	def repoStr(self, repo_path_real):
		real_index = -1
		if repo_path_real:
			real_index = self._repo_paths_real.index(repo_path_real)
		if real_index == -1:
			s = "?"
			self._unknown_repo = True
		else:
			shown_repos = self._shown_repos
			repo_paths = self._repo_paths
			repo_path = repo_paths[real_index]
			index = shown_repos.get(repo_path)
			if index is None:
				index = len(shown_repos)
				shown_repos[repo_path] = index
			s = str(index)
		return s

	def __str__(self):
		output = []
		shown_repos = self._shown_repos
		unknown_repo = self._unknown_repo
		if shown_repos or self._unknown_repo:
			output.append("Portage tree and overlays:\n")
		show_repo_paths = list(shown_repos)
		for repo_path, repo_index in shown_repos.iteritems():
			show_repo_paths[repo_index] = repo_path
		if show_repo_paths:
			for index, repo_path in enumerate(show_repo_paths):
				output.append(" "+teal("["+str(index)+"]")+" %s\n" % repo_path)
		if unknown_repo:
			output.append(" "+teal("[?]") + \
				" indicates that the source repository could not be determined\n")
		return "".join(output)

class PackageCounters(object):

	def __init__(self):
		self.upgrades   = 0
		self.downgrades = 0
		self.new        = 0
		self.newslot    = 0
		self.reinst     = 0
		self.uninst     = 0
		self.blocks     = 0
		self.blocks_satisfied         = 0
		self.totalsize  = 0
		self.restrict_fetch           = 0
		self.restrict_fetch_satisfied = 0
		self.interactive              = 0

	def __str__(self):
		total_installs = self.upgrades + self.downgrades + self.newslot + self.new + self.reinst
		myoutput = []
		details = []
		myoutput.append("Total: %s package" % total_installs)
		if total_installs != 1:
			myoutput.append("s")
		if total_installs != 0:
			myoutput.append(" (")
		if self.upgrades > 0:
			details.append("%s upgrade" % self.upgrades)
			if self.upgrades > 1:
				details[-1] += "s"
		if self.downgrades > 0:
			details.append("%s downgrade" % self.downgrades)
			if self.downgrades > 1:
				details[-1] += "s"
		if self.new > 0:
			details.append("%s new" % self.new)
		if self.newslot > 0:
			details.append("%s in new slot" % self.newslot)
			if self.newslot > 1:
				details[-1] += "s"
		if self.reinst > 0:
			details.append("%s reinstall" % self.reinst)
			if self.reinst > 1:
				details[-1] += "s"
		if self.uninst > 0:
			details.append("%s uninstall" % self.uninst)
			if self.uninst > 1:
				details[-1] += "s"
		if self.interactive > 0:
			details.append("%s %s" % (self.interactive,
				colorize("WARN", "interactive")))
		myoutput.append(", ".join(details))
		if total_installs != 0:
			myoutput.append(")")
		myoutput.append(", Size of downloads: %s" % format_size(self.totalsize))
		if self.restrict_fetch:
			myoutput.append("\nFetch Restriction: %s package" % \
				self.restrict_fetch)
			if self.restrict_fetch > 1:
				myoutput.append("s")
		if self.restrict_fetch_satisfied < self.restrict_fetch:
			myoutput.append(bad(" (%s unsatisfied)") % \
				(self.restrict_fetch - self.restrict_fetch_satisfied))
		if self.blocks > 0:
			myoutput.append("\nConflict: %s block" % \
				self.blocks)
			if self.blocks > 1:
				myoutput.append("s")
			if self.blocks_satisfied < self.blocks:
				myoutput.append(bad(" (%s unsatisfied)") % \
					(self.blocks - self.blocks_satisfied))
		return "".join(myoutput)

class PollSelectAdapter(PollConstants):

	"""
	Use select to emulate a poll object, for
	systems that don't support poll().
	"""

	def __init__(self):
		self._registered = {}
		self._select_args = [[], [], []]

	def register(self, fd, *args):
		"""
		Only POLLIN is currently supported!
		"""
		if len(args) > 1:
			raise TypeError(
				"register expected at most 2 arguments, got " + \
				repr(1 + len(args)))

		eventmask = PollConstants.POLLIN | \
			PollConstants.POLLPRI | PollConstants.POLLOUT
		if args:
			eventmask = args[0]

		self._registered[fd] = eventmask
		self._select_args = None

	def unregister(self, fd):
		self._select_args = None
		del self._registered[fd]

	def poll(self, *args):
		if len(args) > 1:
			raise TypeError(
				"poll expected at most 2 arguments, got " + \
				repr(1 + len(args)))

		timeout = None
		if args:
			timeout = args[0]

		select_args = self._select_args
		if select_args is None:
			select_args = [self._registered.keys(), [], []]

		if timeout is not None:
			select_args = select_args[:]
			# Translate poll() timeout args to select() timeout args:
			#
			#          | units        | value(s) for indefinite block
			# ---------|--------------|------------------------------
			#   poll   | milliseconds | omitted, negative, or None
			# ---------|--------------|------------------------------
			#   select | seconds      | omitted
			# ---------|--------------|------------------------------

			if timeout is not None and timeout < 0:
				timeout = None
			if timeout is not None:
				select_args.append(timeout / 1000)

		select_events = select.select(*select_args)
		poll_events = []
		for fd in select_events[0]:
			poll_events.append((fd, PollConstants.POLLIN))
		return poll_events

class SequentialTaskQueue(SlotObject):

	__slots__ = ("max_jobs", "running_tasks") + \
		("_dirty", "_scheduling", "_task_queue")

	def __init__(self, **kwargs):
		SlotObject.__init__(self, **kwargs)
		self._task_queue = deque()
		self.running_tasks = set()
		if self.max_jobs is None:
			self.max_jobs = 1
		self._dirty = True

	def add(self, task):
		self._task_queue.append(task)
		self._dirty = True

	def addFront(self, task):
		self._task_queue.appendleft(task)
		self._dirty = True

	def schedule(self):

		if not self._dirty:
			return False

		if not self:
			return False

		if self._scheduling:
			# Ignore any recursive schedule() calls triggered via
			# self._task_exit().
			return False

		self._scheduling = True

		task_queue = self._task_queue
		running_tasks = self.running_tasks
		max_jobs = self.max_jobs
		state_changed = False

		while task_queue and \
			(max_jobs is True or len(running_tasks) < max_jobs):
			task = task_queue.popleft()
			cancelled = getattr(task, "cancelled", None)
			if not cancelled:
				running_tasks.add(task)
				task.addExitListener(self._task_exit)
				task.start()
			state_changed = True

		self._dirty = False
		self._scheduling = False

		return state_changed

	def _task_exit(self, task):
		"""
		Since we can always rely on exit listeners being called, the set of
 		running tasks is always pruned automatically and there is never any need
		to actively prune it.
		"""
		self.running_tasks.remove(task)
		if self._task_queue:
			self._dirty = True

	def clear(self):
		self._task_queue.clear()
		running_tasks = self.running_tasks
		while running_tasks:
			task = running_tasks.pop()
			task.removeExitListener(self._task_exit)
			task.cancel()
		self._dirty = False

	def __nonzero__(self):
		return bool(self._task_queue or self.running_tasks)

	def __len__(self):
		return len(self._task_queue) + len(self.running_tasks)

_can_poll_device = None

def can_poll_device():
	"""
	Test if it's possible to use poll() on a device such as a pty. This
	is known to fail on Darwin.
	@rtype: bool
	@returns: True if poll() on a device succeeds, False otherwise.
	"""

	global _can_poll_device
	if _can_poll_device is not None:
		return _can_poll_device

	if not hasattr(select, "poll"):
		_can_poll_device = False
		return _can_poll_device

	try:
		dev_null = open('/dev/null', 'rb')
	except IOError:
		_can_poll_device = False
		return _can_poll_device

	p = select.poll()
	p.register(dev_null.fileno(), PollConstants.POLLIN)

	invalid_request = False
	for f, event in p.poll():
		if event & PollConstants.POLLNVAL:
			invalid_request = True
			break
	dev_null.close()

	_can_poll_device = not invalid_request
	return _can_poll_device

def create_poll_instance():
	"""
	Create an instance of select.poll, or an instance of
	PollSelectAdapter there is no poll() implementation or
	it is broken somehow.
	"""
	if can_poll_device():
		return select.poll()
	return PollSelectAdapter()

getloadavg = getattr(os, "getloadavg", None)
if getloadavg is None:
	def getloadavg():
		"""
		Uses /proc/loadavg to emulate os.getloadavg().
		Raises OSError if the load average was unobtainable.
		"""
		try:
			loadavg_str = open('/proc/loadavg').readline()
		except IOError:
			# getloadavg() is only supposed to raise OSError, so convert
			raise OSError('unknown')
		loadavg_split = loadavg_str.split()
		if len(loadavg_split) < 3:
			raise OSError('unknown')
		loadavg_floats = []
		for i in xrange(3):
			try:
				loadavg_floats.append(float(loadavg_split[i]))
			except ValueError:
				raise OSError('unknown')
		return tuple(loadavg_floats)

class PollScheduler(object):

	class _sched_iface_class(SlotObject):
		__slots__ = ("register", "schedule", "unregister")

	def __init__(self):
		self._max_jobs = 1
		self._max_load = None
		self._jobs = 0
		self._poll_event_queue = []
		self._poll_event_handlers = {}
		self._poll_event_handler_ids = {}
		# Increment id for each new handler.
		self._event_handler_id = 0
		self._poll_obj = create_poll_instance()
		self._scheduling = False

	def _schedule(self):
		"""
		Calls _schedule_tasks() and automatically returns early from
		any recursive calls to this method that the _schedule_tasks()
		call might trigger. This makes _schedule() safe to call from
		inside exit listeners.
		"""
		if self._scheduling:
			return False
		self._scheduling = True
		try:
			return self._schedule_tasks()
		finally:
			self._scheduling = False

	def _running_job_count(self):
		return self._jobs

	def _can_add_job(self):
		max_jobs = self._max_jobs
		max_load = self._max_load

		if self._max_jobs is not True and \
			self._running_job_count() >= self._max_jobs:
			return False

		if max_load is not None and \
			(max_jobs is True or max_jobs > 1) and \
			self._running_job_count() >= 1:
			try:
				avg1, avg5, avg15 = getloadavg()
			except OSError:
				return False

			if avg1 >= max_load:
				return False

		return True

	def _poll(self, timeout=None):
		"""
		All poll() calls pass through here. The poll events
		are added directly to self._poll_event_queue.
		In order to avoid endless blocking, this raises
		StopIteration if timeout is None and there are
		no file descriptors to poll.
		"""
		if not self._poll_event_handlers:
			self._schedule()
			if timeout is None and \
				not self._poll_event_handlers:
				raise StopIteration(
					"timeout is None and there are no poll() event handlers")

		# The following error is known to occur with Linux kernel versions
		# less than 2.6.24:
		#
		#   select.error: (4, 'Interrupted system call')
		#
		# This error has been observed after a SIGSTOP, followed by SIGCONT.
		# Treat it similar to EAGAIN if timeout is None, otherwise just return
		# without any events.
		while True:
			try:
				self._poll_event_queue.extend(self._poll_obj.poll(timeout))
				break
			except select.error, e:
				writemsg_level("\n!!! select error: %s\n" % (e,),
					level=logging.ERROR, noiselevel=-1)
				del e
				if timeout is not None:
					break

	def _next_poll_event(self, timeout=None):
		"""
		Since the _schedule_wait() loop is called by event
		handlers from _poll_loop(), maintain a central event
		queue for both of them to share events from a single
		poll() call. In order to avoid endless blocking, this
		raises StopIteration if timeout is None and there are
		no file descriptors to poll.
		"""
		if not self._poll_event_queue:
			self._poll(timeout)
		return self._poll_event_queue.pop()

	def _poll_loop(self):

		event_handlers = self._poll_event_handlers
		event_handled = False

		try:
			while event_handlers:
				f, event = self._next_poll_event()
				handler, reg_id = event_handlers[f]
				handler(f, event)
				event_handled = True
		except StopIteration:
			event_handled = True

		if not event_handled:
			raise AssertionError("tight loop")

	def _schedule_yield(self):
		"""
		Schedule for a short period of time chosen by the scheduler based
		on internal state. Synchronous tasks should call this periodically
		in order to allow the scheduler to service pending poll events. The
		scheduler will call poll() exactly once, without blocking, and any
		resulting poll events will be serviced.
		"""
		event_handlers = self._poll_event_handlers
		events_handled = 0

		if not event_handlers:
			return bool(events_handled)

		if not self._poll_event_queue:
			self._poll(0)

		try:
			while event_handlers and self._poll_event_queue:
				f, event = self._next_poll_event()
				handler, reg_id = event_handlers[f]
				handler(f, event)
				events_handled += 1
		except StopIteration:
			events_handled += 1

		return bool(events_handled)

	def _register(self, f, eventmask, handler):
		"""
		@rtype: Integer
		@return: A unique registration id, for use in schedule() or
			unregister() calls.
		"""
		if f in self._poll_event_handlers:
			raise AssertionError("fd %d is already registered" % f)
		self._event_handler_id += 1
		reg_id = self._event_handler_id
		self._poll_event_handler_ids[reg_id] = f
		self._poll_event_handlers[f] = (handler, reg_id)
		self._poll_obj.register(f, eventmask)
		return reg_id

	def _unregister(self, reg_id):
		f = self._poll_event_handler_ids[reg_id]
		self._poll_obj.unregister(f)
		del self._poll_event_handlers[f]
		del self._poll_event_handler_ids[reg_id]

	def _schedule_wait(self, wait_ids):
		"""
		Schedule until wait_id is not longer registered
		for poll() events.
		@type wait_id: int
		@param wait_id: a task id to wait for
		"""
		event_handlers = self._poll_event_handlers
		handler_ids = self._poll_event_handler_ids
		event_handled = False

		if isinstance(wait_ids, int):
			wait_ids = frozenset([wait_ids])

		try:
			while wait_ids.intersection(handler_ids):
				f, event = self._next_poll_event()
				handler, reg_id = event_handlers[f]
				handler(f, event)
				event_handled = True
		except StopIteration:
			event_handled = True

		return event_handled

class QueueScheduler(PollScheduler):

	"""
	Add instances of SequentialTaskQueue and then call run(). The
	run() method returns when no tasks remain.
	"""

	def __init__(self, max_jobs=None, max_load=None):
		PollScheduler.__init__(self)

		if max_jobs is None:
			max_jobs = 1

		self._max_jobs = max_jobs
		self._max_load = max_load
		self.sched_iface = self._sched_iface_class(
			register=self._register,
			schedule=self._schedule_wait,
			unregister=self._unregister)

		self._queues = []
		self._schedule_listeners = []

	def add(self, q):
		self._queues.append(q)

	def remove(self, q):
		self._queues.remove(q)

	def run(self):

		while self._schedule():
			self._poll_loop()

		while self._running_job_count():
			self._poll_loop()

	def _schedule_tasks(self):
		"""
		@rtype: bool
		@returns: True if there may be remaining tasks to schedule,
			False otherwise.
		"""
		while self._can_add_job():
			n = self._max_jobs - self._running_job_count()
			if n < 1:
				break

			if not self._start_next_job(n):
				return False

		for q in self._queues:
			if q:
				return True
		return False

	def _running_job_count(self):
		job_count = 0
		for q in self._queues:
			job_count += len(q.running_tasks)
		self._jobs = job_count
		return job_count

	def _start_next_job(self, n=1):
		started_count = 0
		for q in self._queues:
			initial_job_count = len(q.running_tasks)
			q.schedule()
			final_job_count = len(q.running_tasks)
			if final_job_count > initial_job_count:
				started_count += (final_job_count - initial_job_count)
			if started_count >= n:
				break
		return started_count

class TaskScheduler(object):

	"""
	A simple way to handle scheduling of AsynchrousTask instances. Simply
	add tasks and call run(). The run() method returns when no tasks remain.
	"""

	def __init__(self, max_jobs=None, max_load=None):
		self._queue = SequentialTaskQueue(max_jobs=max_jobs)
		self._scheduler = QueueScheduler(
			max_jobs=max_jobs, max_load=max_load)
		self.sched_iface = self._scheduler.sched_iface
		self.run = self._scheduler.run
		self._scheduler.add(self._queue)

	def add(self, task):
		self._queue.add(task)

class JobStatusDisplay(object):

	_bound_properties = ("curval", "failed", "running")
	_jobs_column_width = 48

	# Don't update the display unless at least this much
	# time has passed, in units of seconds.
	_min_display_latency = 2

	_default_term_codes = {
		'cr'  : '\r',
		'el'  : '\x1b[K',
		'nel' : '\n',
	}

	_termcap_name_map = {
		'carriage_return' : 'cr',
		'clr_eol'         : 'el',
		'newline'         : 'nel',
	}

	def __init__(self, out=sys.stdout, quiet=False):
		object.__setattr__(self, "out", out)
		object.__setattr__(self, "quiet", quiet)
		object.__setattr__(self, "maxval", 0)
		object.__setattr__(self, "merges", 0)
		object.__setattr__(self, "_changed", False)
		object.__setattr__(self, "_displayed", False)
		object.__setattr__(self, "_last_display_time", 0)
		object.__setattr__(self, "width", 80)
		self.reset()

		isatty = hasattr(out, "isatty") and out.isatty()
		object.__setattr__(self, "_isatty", isatty)
		if not isatty or not self._init_term():
			term_codes = {}
			for k, capname in self._termcap_name_map.iteritems():
				term_codes[k] = self._default_term_codes[capname]
			object.__setattr__(self, "_term_codes", term_codes)
		encoding = sys.getdefaultencoding()
		for k, v in self._term_codes.items():
			if not isinstance(v, basestring):
				self._term_codes[k] = v.decode(encoding, 'replace')

	def _init_term(self):
		"""
		Initialize term control codes.
		@rtype: bool
		@returns: True if term codes were successfully initialized,
			False otherwise.
		"""

		term_type = os.environ.get("TERM", "vt100")
		tigetstr = None

		try:
			import curses
			try:
				curses.setupterm(term_type, self.out.fileno())
				tigetstr = curses.tigetstr
			except curses.error:
				pass
		except ImportError:
			pass

		if tigetstr is None:
			return False

		term_codes = {}
		for k, capname in self._termcap_name_map.iteritems():
			code = tigetstr(capname)
			if code is None:
				code = self._default_term_codes[capname]
			term_codes[k] = code
		object.__setattr__(self, "_term_codes", term_codes)
		return True

	def _format_msg(self, msg):
		return ">>> %s" % msg

	def _erase(self):
		self.out.write(
			self._term_codes['carriage_return'] + \
			self._term_codes['clr_eol'])
		self.out.flush()
		self._displayed = False

	def _display(self, line):
		self.out.write(line)
		self.out.flush()
		self._displayed = True

	def _update(self, msg):

		out = self.out
		if not self._isatty:
			out.write(self._format_msg(msg) + self._term_codes['newline'])
			self.out.flush()
			self._displayed = True
			return

		if self._displayed:
			self._erase()

		self._display(self._format_msg(msg))

	def displayMessage(self, msg):

		was_displayed = self._displayed

		if self._isatty and self._displayed:
			self._erase()

		self.out.write(self._format_msg(msg) + self._term_codes['newline'])
		self.out.flush()
		self._displayed = False

		if was_displayed:
			self._changed = True
			self.display()

	def reset(self):
		self.maxval = 0
		self.merges = 0
		for name in self._bound_properties:
			object.__setattr__(self, name, 0)

		if self._displayed:
			self.out.write(self._term_codes['newline'])
			self.out.flush()
			self._displayed = False

	def __setattr__(self, name, value):
		old_value = getattr(self, name)
		if value == old_value:
			return
		object.__setattr__(self, name, value)
		if name in self._bound_properties:
			self._property_change(name, old_value, value)

	def _property_change(self, name, old_value, new_value):
		self._changed = True
		self.display()

	def _load_avg_str(self):
		try:
			avg = getloadavg()
		except OSError:
			return 'unknown'

		max_avg = max(avg)

		if max_avg < 10:
			digits = 2
		elif max_avg < 100:
			digits = 1
		else:
			digits = 0

		return ", ".join(("%%.%df" % digits ) % x for x in avg)

	def display(self):
		"""
		Display status on stdout, but only if something has
		changed since the last call.
		"""

		if self.quiet:
			return

		current_time = time.time()
		time_delta = current_time - self._last_display_time
		if self._displayed and \
			not self._changed:
			if not self._isatty:
				return
			if time_delta < self._min_display_latency:
				return

		self._last_display_time = current_time
		self._changed = False
		self._display_status()

	def _display_status(self):
		# Don't use len(self._completed_tasks) here since that also
		# can include uninstall tasks.
		curval_str = str(self.curval)
		maxval_str = str(self.maxval)
		running_str = str(self.running)
		failed_str = str(self.failed)
		load_avg_str = self._load_avg_str()

		color_output = StringIO()
		plain_output = StringIO()
		style_file = portage.output.ConsoleStyleFile(color_output)
		style_file.write_listener = plain_output
		style_writer = portage.output.StyleWriter(file=style_file, maxcol=9999)
		style_writer.style_listener = style_file.new_styles
		f = formatter.AbstractFormatter(style_writer)

		number_style = "INFORM"
		f.add_literal_data("Jobs: ")
		f.push_style(number_style)
		f.add_literal_data(curval_str)
		f.pop_style()
		f.add_literal_data(" of ")
		f.push_style(number_style)
		f.add_literal_data(maxval_str)
		f.pop_style()
		f.add_literal_data(" complete")

		if self.running:
			f.add_literal_data(", ")
			f.push_style(number_style)
			f.add_literal_data(running_str)
			f.pop_style()
			f.add_literal_data(" running")

		if self.failed:
			f.add_literal_data(", ")
			f.push_style(number_style)
			f.add_literal_data(failed_str)
			f.pop_style()
			f.add_literal_data(" failed")

		padding = self._jobs_column_width - len(plain_output.getvalue())
		if padding > 0:
			f.add_literal_data(padding * " ")

		f.add_literal_data("Load avg: ")
		f.add_literal_data(load_avg_str)

		# Truncate to fit width, to avoid making the terminal scroll if the
		# line overflows (happens when the load average is large).
		plain_output = plain_output.getvalue()
		if self._isatty and len(plain_output) > self.width:
			# Use plain_output here since it's easier to truncate
			# properly than the color output which contains console
			# color codes.
			self._update(plain_output[:self.width])
		else:
			self._update(color_output.getvalue())

		xtermTitle(" ".join(plain_output.split()))

class Scheduler(PollScheduler):

	_opts_ignore_blockers = \
		frozenset(["--buildpkgonly",
		"--fetchonly", "--fetch-all-uri",
		"--nodeps", "--pretend"])

	_opts_no_background = \
		frozenset(["--pretend",
		"--fetchonly", "--fetch-all-uri"])

	_opts_no_restart = frozenset(["--buildpkgonly",
		"--fetchonly", "--fetch-all-uri", "--pretend"])

	_bad_resume_opts = set(["--ask", "--changelog",
		"--resume", "--skipfirst"])

	_fetch_log = "/var/log/emerge-fetch.log"

	class _iface_class(SlotObject):
		__slots__ = ("dblinkEbuildPhase", "dblinkDisplayMerge",
			"dblinkElog", "fetch", "register", "schedule",
			"scheduleSetup", "scheduleUnpack", "scheduleYield",
			"unregister")

	class _fetch_iface_class(SlotObject):
		__slots__ = ("log_file", "schedule")

	_task_queues_class = slot_dict_class(
		("merge", "jobs", "fetch", "unpack"), prefix="")

	class _build_opts_class(SlotObject):
		__slots__ = ("buildpkg", "buildpkgonly",
			"fetch_all_uri", "fetchonly", "pretend")

	class _binpkg_opts_class(SlotObject):
		__slots__ = ("fetchonly", "getbinpkg", "pretend")

	class _pkg_count_class(SlotObject):
		__slots__ = ("curval", "maxval")

	class _emerge_log_class(SlotObject):
		__slots__ = ("xterm_titles",)

		def log(self, *pargs, **kwargs):
			if not self.xterm_titles:
				# Avoid interference with the scheduler's status display.
				kwargs.pop("short_msg", None)
			emergelog(self.xterm_titles, *pargs, **kwargs)

	class _failed_pkg(SlotObject):
		__slots__ = ("build_dir", "build_log", "pkg", "returncode")

	class _ConfigPool(object):
		"""Interface for a task to temporarily allocate a config
		instance from a pool. This allows a task to be constructed
		long before the config instance actually becomes needed, like
		when prefetchers are constructed for the whole merge list."""
		__slots__ = ("_root", "_allocate", "_deallocate")
		def __init__(self, root, allocate, deallocate):
			self._root = root
			self._allocate = allocate
			self._deallocate = deallocate
		def allocate(self):
			return self._allocate(self._root)
		def deallocate(self, settings):
			self._deallocate(settings)

	class _unknown_internal_error(portage.exception.PortageException):
		"""
		Used internally to terminate scheduling. The specific reason for
		the failure should have been dumped to stderr.
		"""
		def __init__(self, value=""):
			portage.exception.PortageException.__init__(self, value)

	def __init__(self, settings, trees, mtimedb, myopts,
		spinner, mergelist, favorites, digraph):
		PollScheduler.__init__(self)
		self.settings = settings
		self.target_root = settings["ROOT"]
		self.trees = trees
		self.myopts = myopts
		self._spinner = spinner
		self._mtimedb = mtimedb
		self._mergelist = mergelist
		self._favorites = favorites
		self._args_set = InternalPackageSet(favorites)
		self._build_opts = self._build_opts_class()
		for k in self._build_opts.__slots__:
			setattr(self._build_opts, k, "--" + k.replace("_", "-") in myopts)
		self._binpkg_opts = self._binpkg_opts_class()
		for k in self._binpkg_opts.__slots__:
			setattr(self._binpkg_opts, k, "--" + k.replace("_", "-") in myopts)

		self.curval = 0
		self._logger = self._emerge_log_class()
		self._task_queues = self._task_queues_class()
		for k in self._task_queues.allowed_keys:
			setattr(self._task_queues, k,
				SequentialTaskQueue())

		# Holds merges that will wait to be executed when no builds are
		# executing. This is useful for system packages since dependencies
		# on system packages are frequently unspecified.
		self._merge_wait_queue = []
		# Holds merges that have been transfered from the merge_wait_queue to
		# the actual merge queue. They are removed from this list upon
		# completion. Other packages can start building only when this list is
		# empty.
		self._merge_wait_scheduled = []

		# Holds system packages and their deep runtime dependencies. Before
		# being merged, these packages go to merge_wait_queue, to be merged
		# when no other packages are building.
		self._deep_system_deps = set()

		# Holds packages to merge which will satisfy currently unsatisfied
		# deep runtime dependencies of system packages. If this is not empty
		# then no parallel builds will be spawned until it is empty. This
		# minimizes the possibility that a build will fail due to the system
		# being in a fragile state. For example, see bug #259954.
		self._unsatisfied_system_deps = set()

		self._status_display = JobStatusDisplay()
		self._max_load = myopts.get("--load-average")
		max_jobs = myopts.get("--jobs")
		if max_jobs is None:
			max_jobs = 1
		self._set_max_jobs(max_jobs)

		# The root where the currently running
		# portage instance is installed.
		self._running_root = trees["/"]["root_config"]
		self.edebug = 0
		if settings.get("PORTAGE_DEBUG", "") == "1":
			self.edebug = 1
		self.pkgsettings = {}
		self._config_pool = {}
		self._blocker_db = {}
		for root in trees:
			self._config_pool[root] = []
			self._blocker_db[root] = BlockerDB(trees[root]["root_config"])

		fetch_iface = self._fetch_iface_class(log_file=self._fetch_log,
			schedule=self._schedule_fetch)
		self._sched_iface = self._iface_class(
			dblinkEbuildPhase=self._dblink_ebuild_phase,
			dblinkDisplayMerge=self._dblink_display_merge,
			dblinkElog=self._dblink_elog,
			fetch=fetch_iface, register=self._register,
			schedule=self._schedule_wait,
			scheduleSetup=self._schedule_setup,
			scheduleUnpack=self._schedule_unpack,
			scheduleYield=self._schedule_yield,
			unregister=self._unregister)

		self._prefetchers = weakref.WeakValueDictionary()
		self._pkg_queue = []
		self._completed_tasks = set()

		self._failed_pkgs = []
		self._failed_pkgs_all = []
		self._failed_pkgs_die_msgs = []
		self._post_mod_echo_msgs = []
		self._parallel_fetch = False
		merge_count = len([x for x in mergelist \
			if isinstance(x, Package) and x.operation == "merge"])
		self._pkg_count = self._pkg_count_class(
			curval=0, maxval=merge_count)
		self._status_display.maxval = self._pkg_count.maxval

		# The load average takes some time to respond when new
		# jobs are added, so we need to limit the rate of adding
		# new jobs.
		self._job_delay_max = 10
		self._job_delay_factor = 1.0
		self._job_delay_exp = 1.5
		self._previous_job_start_time = None

		self._set_digraph(digraph)

		# This is used to memoize the _choose_pkg() result when
		# no packages can be chosen until one of the existing
		# jobs completes.
		self._choose_pkg_return_early = False

		features = self.settings.features
		if "parallel-fetch" in features and \
			not ("--pretend" in self.myopts or \
			"--fetch-all-uri" in self.myopts or \
			"--fetchonly" in self.myopts):
			if "distlocks" not in features:
				portage.writemsg(red("!!!")+"\n", noiselevel=-1)
				portage.writemsg(red("!!!")+" parallel-fetching " + \
					"requires the distlocks feature enabled"+"\n",
					noiselevel=-1)
				portage.writemsg(red("!!!")+" you have it disabled, " + \
					"thus parallel-fetching is being disabled"+"\n",
					noiselevel=-1)
				portage.writemsg(red("!!!")+"\n", noiselevel=-1)
			elif len(mergelist) > 1:
				self._parallel_fetch = True

		if self._parallel_fetch:
				# clear out existing fetch log if it exists
				try:
					open(self._fetch_log, 'w')
				except EnvironmentError:
					pass

		self._running_portage = None
		portage_match = self._running_root.trees["vartree"].dbapi.match(
			portage.const.PORTAGE_PACKAGE_ATOM)
		if portage_match:
			cpv = portage_match.pop()
			self._running_portage = self._pkg(cpv, "installed",
				self._running_root, installed=True)

	def _poll(self, timeout=None):
		self._schedule()
		PollScheduler._poll(self, timeout=timeout)

	def _set_max_jobs(self, max_jobs):
		self._max_jobs = max_jobs
		self._task_queues.jobs.max_jobs = max_jobs

	def _background_mode(self):
		"""
		Check if background mode is enabled and adjust states as necessary.

		@rtype: bool
		@returns: True if background mode is enabled, False otherwise.
		"""
		background = (self._max_jobs is True or \
			self._max_jobs > 1 or "--quiet" in self.myopts) and \
			not bool(self._opts_no_background.intersection(self.myopts))

		if background:
			interactive_tasks = self._get_interactive_tasks()
			if interactive_tasks:
				background = False
				writemsg_level(">>> Sending package output to stdio due " + \
					"to interactive package(s):\n",
					level=logging.INFO, noiselevel=-1)
				msg = [""]
				for pkg in interactive_tasks:
					pkg_str = "  " + colorize("INFORM", str(pkg.cpv))
					if pkg.root != "/":
						pkg_str += " for " + pkg.root
					msg.append(pkg_str)
				msg.append("")
				writemsg_level("".join("%s\n" % (l,) for l in msg),
					level=logging.INFO, noiselevel=-1)
				if self._max_jobs is True or self._max_jobs > 1:
					self._set_max_jobs(1)
					writemsg_level(">>> Setting --jobs=1 due " + \
						"to the above interactive package(s)\n",
						level=logging.INFO, noiselevel=-1)

		self._status_display.quiet = \
			not background or \
			("--quiet" in self.myopts and \
			"--verbose" not in self.myopts)

		self._logger.xterm_titles = \
			"notitles" not in self.settings.features and \
			self._status_display.quiet

		return background

	def _get_interactive_tasks(self):
		from portage import flatten
		from portage.dep import use_reduce, paren_reduce
		interactive_tasks = []
		for task in self._mergelist:
			if not (isinstance(task, Package) and \
				task.operation == "merge"):
				continue
			try:
				properties = flatten(use_reduce(paren_reduce(
					task.metadata["PROPERTIES"]), uselist=task.use.enabled))
			except portage.exception.InvalidDependString, e:
				show_invalid_depstring_notice(task,
					task.metadata["PROPERTIES"], str(e))
				raise self._unknown_internal_error()
			if "interactive" in properties:
				interactive_tasks.append(task)
		return interactive_tasks

	def _set_digraph(self, digraph):
		if "--nodeps" in self.myopts or \
			(self._max_jobs is not True and self._max_jobs < 2):
			# save some memory
			self._digraph = None
			return

		self._digraph = digraph
		self._find_system_deps()
		self._prune_digraph()
		self._prevent_builddir_collisions()

	def _find_system_deps(self):
		"""
		Find system packages and their deep runtime dependencies. Before being
		merged, these packages go to merge_wait_queue, to be merged when no
		other packages are building.
		"""
		deep_system_deps = self._deep_system_deps
		deep_system_deps.clear()
		deep_system_deps.update(
			_find_deep_system_runtime_deps(self._digraph))
		deep_system_deps.difference_update([pkg for pkg in \
			deep_system_deps if pkg.operation != "merge"])

	def _prune_digraph(self):
		"""
		Prune any root nodes that are irrelevant.
		"""

		graph = self._digraph
		completed_tasks = self._completed_tasks
		removed_nodes = set()
		while True:
			for node in graph.root_nodes():
				if not isinstance(node, Package) or \
					(node.installed and node.operation == "nomerge") or \
					node.onlydeps or \
					node in completed_tasks:
					removed_nodes.add(node)
			if removed_nodes:
				graph.difference_update(removed_nodes)
			if not removed_nodes:
				break
			removed_nodes.clear()

	def _prevent_builddir_collisions(self):
		"""
		When building stages, sometimes the same exact cpv needs to be merged
		to both $ROOTs. Add edges to the digraph in order to avoid collisions
		in the builddir. Currently, normal file locks would be inappropriate
		for this purpose since emerge holds all of it's build dir locks from
		the main process.
		"""
		cpv_map = {}
		for pkg in self._mergelist:
			if not isinstance(pkg, Package):
				# a satisfied blocker
				continue
			if pkg.installed:
				continue
			if pkg.cpv not in cpv_map:
				cpv_map[pkg.cpv] = [pkg]
				continue
			for earlier_pkg in cpv_map[pkg.cpv]:
				self._digraph.add(earlier_pkg, pkg,
					priority=DepPriority(buildtime=True))
			cpv_map[pkg.cpv].append(pkg)

	class _pkg_failure(portage.exception.PortageException):
		"""
		An instance of this class is raised by unmerge() when
		an uninstallation fails.
		"""
		status = 1
		def __init__(self, *pargs):
			portage.exception.PortageException.__init__(self, pargs)
			if pargs:
				self.status = pargs[0]

	def _schedule_fetch(self, fetcher):
		"""
		Schedule a fetcher on the fetch queue, in order to
		serialize access to the fetch log.
		"""
		self._task_queues.fetch.addFront(fetcher)

	def _schedule_setup(self, setup_phase):
		"""
		Schedule a setup phase on the merge queue, in order to
		serialize unsandboxed access to the live filesystem.
		"""
		self._task_queues.merge.addFront(setup_phase)
		self._schedule()

	def _schedule_unpack(self, unpack_phase):
		"""
		Schedule an unpack phase on the unpack queue, in order
		to serialize $DISTDIR access for live ebuilds.
		"""
		self._task_queues.unpack.add(unpack_phase)

	def _find_blockers(self, new_pkg):
		"""
		Returns a callable which should be called only when
		the vdb lock has been acquired.
		"""
		def get_blockers():
			return self._find_blockers_with_lock(new_pkg, acquire_lock=0)
		return get_blockers

	def _find_blockers_with_lock(self, new_pkg, acquire_lock=0):
		if self._opts_ignore_blockers.intersection(self.myopts):
			return None

		# Call gc.collect() here to avoid heap overflow that
		# triggers 'Cannot allocate memory' errors (reported
		# with python-2.5).
		import gc
		gc.collect()

		blocker_db = self._blocker_db[new_pkg.root]

		blocker_dblinks = []
		for blocking_pkg in blocker_db.findInstalledBlockers(
			new_pkg, acquire_lock=acquire_lock):
			if new_pkg.slot_atom == blocking_pkg.slot_atom:
				continue
			if new_pkg.cpv == blocking_pkg.cpv:
				continue
			blocker_dblinks.append(portage.dblink(
				blocking_pkg.category, blocking_pkg.pf, blocking_pkg.root,
				self.pkgsettings[blocking_pkg.root], treetype="vartree",
				vartree=self.trees[blocking_pkg.root]["vartree"]))

		gc.collect()

		return blocker_dblinks

	def _dblink_pkg(self, pkg_dblink):
		cpv = pkg_dblink.mycpv
		type_name = RootConfig.tree_pkg_map[pkg_dblink.treetype]
		root_config = self.trees[pkg_dblink.myroot]["root_config"]
		installed = type_name == "installed"
		return self._pkg(cpv, type_name, root_config, installed=installed)

	def _append_to_log_path(self, log_path, msg):
		f = open(log_path, 'a')
		try:
			f.write(msg)
		finally:
			f.close()

	def _dblink_elog(self, pkg_dblink, phase, func, msgs):

		log_path = pkg_dblink.settings.get("PORTAGE_LOG_FILE")
		log_file = None
		out = sys.stdout
		background = self._background

		if background and log_path is not None:
			log_file = open(log_path, 'a')
			out = log_file

		try:
			for msg in msgs:
				func(msg, phase=phase, key=pkg_dblink.mycpv, out=out)
		finally:
			if log_file is not None:
				log_file.close()

	def _dblink_display_merge(self, pkg_dblink, msg, level=0, noiselevel=0):
		log_path = pkg_dblink.settings.get("PORTAGE_LOG_FILE")
		background = self._background

		if log_path is None:
			if not (background and level < logging.WARN):
				portage.util.writemsg_level(msg,
					level=level, noiselevel=noiselevel)
		else:
			if not background:
				portage.util.writemsg_level(msg,
					level=level, noiselevel=noiselevel)
			self._append_to_log_path(log_path, msg)

	def _dblink_ebuild_phase(self,
		pkg_dblink, pkg_dbapi, ebuild_path, phase):
		"""
		Using this callback for merge phases allows the scheduler
		to run while these phases execute asynchronously, and allows
		the scheduler control output handling.
		"""

		scheduler = self._sched_iface
		settings = pkg_dblink.settings
		pkg = self._dblink_pkg(pkg_dblink)
		background = self._background
		log_path = settings.get("PORTAGE_LOG_FILE")

		ebuild_phase = EbuildPhase(background=background,
			pkg=pkg, phase=phase, scheduler=scheduler,
			settings=settings, tree=pkg_dblink.treetype)
		ebuild_phase.start()
		ebuild_phase.wait()

		return ebuild_phase.returncode

	def _generate_digests(self):
		"""
		Generate digests if necessary for --digests or FEATURES=digest.
		In order to avoid interference, this must done before parallel
		tasks are started.
		"""

		if '--fetchonly' in self.myopts:
			return os.EX_OK

		digest = '--digest' in self.myopts
		if not digest:
			for pkgsettings in self.pkgsettings.itervalues():
				if 'digest' in pkgsettings.features:
					digest = True
					break

		if not digest:
			return os.EX_OK

		for x in self._mergelist:
			if not isinstance(x, Package) or \
				x.type_name != 'ebuild' or \
				x.operation != 'merge':
				continue
			pkgsettings = self.pkgsettings[x.root]
			if '--digest' not in self.myopts and \
				'digest' not in pkgsettings.features:
				continue
			portdb = x.root_config.trees['porttree'].dbapi
			ebuild_path = portdb.findname(x.cpv)
			if not ebuild_path:
				writemsg_level(
					"!!! Could not locate ebuild for '%s'.\n" \
					% x.cpv, level=logging.ERROR, noiselevel=-1)
				return 1
			pkgsettings['O'] = os.path.dirname(ebuild_path)
			if not portage.digestgen([], pkgsettings, myportdb=portdb):
				writemsg_level(
					"!!! Unable to generate manifest for '%s'.\n" \
					% x.cpv, level=logging.ERROR, noiselevel=-1)
				return 1

		return os.EX_OK

	def _check_manifests(self):
		# Verify all the manifests now so that the user is notified of failure
		# as soon as possible.
		if "strict" not in self.settings.features or \
			"--fetchonly" in self.myopts or \
			"--fetch-all-uri" in self.myopts:
			return os.EX_OK

		shown_verifying_msg = False
		quiet_settings = {}
		for myroot, pkgsettings in self.pkgsettings.iteritems():
			quiet_config = portage.config(clone=pkgsettings)
			quiet_config["PORTAGE_QUIET"] = "1"
			quiet_config.backup_changes("PORTAGE_QUIET")
			quiet_settings[myroot] = quiet_config
			del quiet_config

		for x in self._mergelist:
			if not isinstance(x, Package) or \
				x.type_name != "ebuild":
				continue

			if not shown_verifying_msg:
				shown_verifying_msg = True
				self._status_msg("Verifying ebuild manifests")

			root_config = x.root_config
			portdb = root_config.trees["porttree"].dbapi
			quiet_config = quiet_settings[root_config.root]
			quiet_config["O"] = os.path.dirname(portdb.findname(x.cpv))
			if not portage.digestcheck([], quiet_config, strict=True):
				return 1

		return os.EX_OK

	def _add_prefetchers(self):

		if not self._parallel_fetch:
			return

		if self._parallel_fetch:
			self._status_msg("Starting parallel fetch")

			prefetchers = self._prefetchers
			getbinpkg = "--getbinpkg" in self.myopts

			# In order to avoid "waiting for lock" messages
			# at the beginning, which annoy users, never
			# spawn a prefetcher for the first package.
			for pkg in self._mergelist[1:]:
				prefetcher = self._create_prefetcher(pkg)
				if prefetcher is not None:
					self._task_queues.fetch.add(prefetcher)
					prefetchers[pkg] = prefetcher

	def _create_prefetcher(self, pkg):
		"""
		@return: a prefetcher, or None if not applicable
		"""
		prefetcher = None

		if not isinstance(pkg, Package):
			pass

		elif pkg.type_name == "ebuild":

			prefetcher = EbuildFetcher(background=True,
				config_pool=self._ConfigPool(pkg.root,
				self._allocate_config, self._deallocate_config),
				fetchonly=1, logfile=self._fetch_log,
				pkg=pkg, prefetch=True, scheduler=self._sched_iface)

		elif pkg.type_name == "binary" and \
			"--getbinpkg" in self.myopts and \
			pkg.root_config.trees["bintree"].isremote(pkg.cpv):

			prefetcher = BinpkgPrefetcher(background=True,
				pkg=pkg, scheduler=self._sched_iface)

		return prefetcher

	def _is_restart_scheduled(self):
		"""
		Check if the merge list contains a replacement
		for the current running instance, that will result
		in restart after merge.
		@rtype: bool
		@returns: True if a restart is scheduled, False otherwise.
		"""
		if self._opts_no_restart.intersection(self.myopts):
			return False

		mergelist = self._mergelist

		for i, pkg in enumerate(mergelist):
			if self._is_restart_necessary(pkg) and \
				i != len(mergelist) - 1:
				return True

		return False

	def _is_restart_necessary(self, pkg):
		"""
		@return: True if merging the given package
			requires restart, False otherwise.
		"""

		# Figure out if we need a restart.
		if pkg.root == self._running_root.root and \
			portage.match_from_list(
			portage.const.PORTAGE_PACKAGE_ATOM, [pkg]):
			if self._running_portage:
				return pkg.cpv != self._running_portage.cpv
			return True
		return False

	def _restart_if_necessary(self, pkg):
		"""
		Use execv() to restart emerge. This happens
		if portage upgrades itself and there are
		remaining packages in the list.
		"""

		if self._opts_no_restart.intersection(self.myopts):
			return

		if not self._is_restart_necessary(pkg):
			return

		if pkg == self._mergelist[-1]:
			return

		self._main_loop_cleanup()

		logger = self._logger
		pkg_count = self._pkg_count
		mtimedb = self._mtimedb
		bad_resume_opts = self._bad_resume_opts

		logger.log(" ::: completed emerge (%s of %s) %s to %s" % \
			(pkg_count.curval, pkg_count.maxval, pkg.cpv, pkg.root))

		logger.log(" *** RESTARTING " + \
			"emerge via exec() after change of " + \
			"portage version.")

		mtimedb["resume"]["mergelist"].remove(list(pkg))
		mtimedb.commit()
		portage.run_exitfuncs()
		mynewargv = [sys.argv[0], "--resume"]
		resume_opts = self.myopts.copy()
		# For automatic resume, we need to prevent
		# any of bad_resume_opts from leaking in
		# via EMERGE_DEFAULT_OPTS.
		resume_opts["--ignore-default-opts"] = True
		for myopt, myarg in resume_opts.iteritems():
			if myopt not in bad_resume_opts:
				if myarg is True:
					mynewargv.append(myopt)
				else:
					mynewargv.append(myopt +"="+ str(myarg))
		# priority only needs to be adjusted on the first run
		os.environ["PORTAGE_NICENESS"] = "0"
		os.execv(mynewargv[0], mynewargv)

	def merge(self):

		if "--resume" in self.myopts:
			# We're resuming.
			portage.writemsg_stdout(
				colorize("GOOD", "*** Resuming merge...\n"), noiselevel=-1)
			self._logger.log(" *** Resuming merge...")

		self._save_resume_list()

		try:
			self._background = self._background_mode()
		except self._unknown_internal_error:
			return 1

		for root in self.trees:
			root_config = self.trees[root]["root_config"]

			# Even for --pretend --fetch mode, PORTAGE_TMPDIR is required
			# since it might spawn pkg_nofetch which requires PORTAGE_BUILDDIR
			# for ensuring sane $PWD (bug #239560) and storing elog messages.
			tmpdir = root_config.settings.get("PORTAGE_TMPDIR", "")
			if not tmpdir or not os.path.isdir(tmpdir):
				msg = "The directory specified in your " + \
					"PORTAGE_TMPDIR variable, '%s', " % tmpdir + \
				"does not exist. Please create this " + \
				"directory or correct your PORTAGE_TMPDIR setting."
				msg = textwrap.wrap(msg, 70)
				out = portage.output.EOutput()
				for l in msg:
					out.eerror(l)
				return 1

			if self._background:
				root_config.settings.unlock()
				root_config.settings["PORTAGE_BACKGROUND"] = "1"
				root_config.settings.backup_changes("PORTAGE_BACKGROUND")
				root_config.settings.lock()

			self.pkgsettings[root] = portage.config(
				clone=root_config.settings)

		rval = self._generate_digests()
		if rval != os.EX_OK:
			return rval

		rval = self._check_manifests()
		if rval != os.EX_OK:
			return rval

		keep_going = "--keep-going" in self.myopts
		fetchonly = self._build_opts.fetchonly
		mtimedb = self._mtimedb
		failed_pkgs = self._failed_pkgs

		while True:
			rval = self._merge()
			if rval == os.EX_OK or fetchonly or not keep_going:
				break
			if "resume" not in mtimedb:
				break
			mergelist = self._mtimedb["resume"].get("mergelist")
			if not mergelist:
				break

			if not failed_pkgs:
				break

			for failed_pkg in failed_pkgs:
				mergelist.remove(list(failed_pkg.pkg))

			self._failed_pkgs_all.extend(failed_pkgs)
			del failed_pkgs[:]

			if not mergelist:
				break

			if not self._calc_resume_list():
				break

			clear_caches(self.trees)
			if not self._mergelist:
				break

			self._save_resume_list()
			self._pkg_count.curval = 0
			self._pkg_count.maxval = len([x for x in self._mergelist \
				if isinstance(x, Package) and x.operation == "merge"])
			self._status_display.maxval = self._pkg_count.maxval

		self._logger.log(" *** Finished. Cleaning up...")

		if failed_pkgs:
			self._failed_pkgs_all.extend(failed_pkgs)
			del failed_pkgs[:]

		background = self._background
		failure_log_shown = False
		if background and len(self._failed_pkgs_all) == 1:
			# If only one package failed then just show it's
			# whole log for easy viewing.
			failed_pkg = self._failed_pkgs_all[-1]
			build_dir = failed_pkg.build_dir
			log_file = None

			log_paths = [failed_pkg.build_log]

			log_path = self._locate_failure_log(failed_pkg)
			if log_path is not None:
				try:
					log_file = open(log_path)
				except IOError:
					pass

			if log_file is not None:
				try:
					for line in log_file:
						writemsg_level(line, noiselevel=-1)
				finally:
					log_file.close()
				failure_log_shown = True

		# Dump mod_echo output now since it tends to flood the terminal.
		# This allows us to avoid having more important output, generated
		# later, from being swept away by the mod_echo output.
		mod_echo_output =  _flush_elog_mod_echo()

		if background and not failure_log_shown and \
			self._failed_pkgs_all and \
			self._failed_pkgs_die_msgs and \
			not mod_echo_output:

			printer = portage.output.EOutput()
			for mysettings, key, logentries in self._failed_pkgs_die_msgs:
				root_msg = ""
				if mysettings["ROOT"] != "/":
					root_msg = " merged to %s" % mysettings["ROOT"]
				print
				printer.einfo("Error messages for package %s%s:" % \
					(colorize("INFORM", key), root_msg))
				print
				for phase in portage.const.EBUILD_PHASES:
					if phase not in logentries:
						continue
					for msgtype, msgcontent in logentries[phase]:
						if isinstance(msgcontent, basestring):
							msgcontent = [msgcontent]
						for line in msgcontent:
							printer.eerror(line.strip("\n"))

		if self._post_mod_echo_msgs:
			for msg in self._post_mod_echo_msgs:
				msg()

		if len(self._failed_pkgs_all) > 1 or \
			(self._failed_pkgs_all and "--keep-going" in self.myopts):
			if len(self._failed_pkgs_all) > 1:
				msg = "The following %d packages have " % \
					len(self._failed_pkgs_all) + \
					"failed to build or install:"
			else:
				msg = "The following package has " + \
					"failed to build or install:"
			prefix = bad(" * ")
			writemsg(prefix + "\n", noiselevel=-1)
			from textwrap import wrap
			for line in wrap(msg, 72):
				writemsg("%s%s\n" % (prefix, line), noiselevel=-1)
			writemsg(prefix + "\n", noiselevel=-1)
			for failed_pkg in self._failed_pkgs_all:
				writemsg("%s\t%s\n" % (prefix,
					colorize("INFORM", str(failed_pkg.pkg))),
					noiselevel=-1)
			writemsg(prefix + "\n", noiselevel=-1)

		return rval

	def _elog_listener(self, mysettings, key, logentries, fulltext):
		errors = portage.elog.filter_loglevels(logentries, ["ERROR"])
		if errors:
			self._failed_pkgs_die_msgs.append(
				(mysettings, key, errors))

	def _locate_failure_log(self, failed_pkg):

		build_dir = failed_pkg.build_dir
		log_file = None

		log_paths = [failed_pkg.build_log]

		for log_path in log_paths:
			if not log_path:
				continue

			try:
				log_size = os.stat(log_path).st_size
			except OSError:
				continue

			if log_size == 0:
				continue

			return log_path

		return None

	def _add_packages(self):
		pkg_queue = self._pkg_queue
		for pkg in self._mergelist:
			if isinstance(pkg, Package):
				pkg_queue.append(pkg)
			elif isinstance(pkg, Blocker):
				pass

	def _system_merge_started(self, merge):
		"""
		Add any unsatisfied runtime deps to self._unsatisfied_system_deps.
		"""
		graph = self._digraph
		if graph is None:
			return
		pkg = merge.merge.pkg

		# Skip this if $ROOT != / since it shouldn't matter if there
		# are unsatisfied system runtime deps in this case.
		if pkg.root != '/':
			return

		completed_tasks = self._completed_tasks
		unsatisfied = self._unsatisfied_system_deps

		def ignore_non_runtime_or_satisfied(priority):
			"""
			Ignore non-runtime and satisfied runtime priorities.
			"""
			if isinstance(priority, DepPriority) and \
				not priority.satisfied and \
				(priority.runtime or priority.runtime_post):
				return False
			return True

		# When checking for unsatisfied runtime deps, only check
		# direct deps since indirect deps are checked when the
		# corresponding parent is merged.
		for child in graph.child_nodes(pkg,
			ignore_priority=ignore_non_runtime_or_satisfied):
			if not isinstance(child, Package) or \
				child.operation == 'uninstall':
				continue
			if child is pkg:
				continue
			if child.operation == 'merge' and \
				child not in completed_tasks:
				unsatisfied.add(child)

	def _merge_wait_exit_handler(self, task):
		self._merge_wait_scheduled.remove(task)
		self._merge_exit(task)

	def _merge_exit(self, merge):
		self._do_merge_exit(merge)
		self._deallocate_config(merge.merge.settings)
		if merge.returncode == os.EX_OK and \
			not merge.merge.pkg.installed:
			self._status_display.curval += 1
		self._status_display.merges = len(self._task_queues.merge)
		self._schedule()

	def _do_merge_exit(self, merge):
		pkg = merge.merge.pkg
		if merge.returncode != os.EX_OK:
			settings = merge.merge.settings
			build_dir = settings.get("PORTAGE_BUILDDIR")
			build_log = settings.get("PORTAGE_LOG_FILE")

			self._failed_pkgs.append(self._failed_pkg(
				build_dir=build_dir, build_log=build_log,
				pkg=pkg,
				returncode=merge.returncode))
			self._failed_pkg_msg(self._failed_pkgs[-1], "install", "to")

			self._status_display.failed = len(self._failed_pkgs)
			return

		self._task_complete(pkg)
		pkg_to_replace = merge.merge.pkg_to_replace
		if pkg_to_replace is not None:
			# When a package is replaced, mark it's uninstall
			# task complete (if any).
			uninst_hash_key = \
				("installed", pkg.root, pkg_to_replace.cpv, "uninstall")
			self._task_complete(uninst_hash_key)

		if pkg.installed:
			return

		self._restart_if_necessary(pkg)

		# Call mtimedb.commit() after each merge so that
		# --resume still works after being interrupted
		# by reboot, sigkill or similar.
		mtimedb = self._mtimedb
		mtimedb["resume"]["mergelist"].remove(list(pkg))
		if not mtimedb["resume"]["mergelist"]:
			del mtimedb["resume"]
		mtimedb.commit()

	def _build_exit(self, build):
		if build.returncode == os.EX_OK:
			self.curval += 1
			merge = PackageMerge(merge=build)
			if not build.build_opts.buildpkgonly and \
				build.pkg in self._deep_system_deps:
				# Since dependencies on system packages are frequently
				# unspecified, merge them only when no builds are executing.
				self._merge_wait_queue.append(merge)
				merge.addStartListener(self._system_merge_started)
			else:
				merge.addExitListener(self._merge_exit)
				self._task_queues.merge.add(merge)
				self._status_display.merges = len(self._task_queues.merge)
		else:
			settings = build.settings
			build_dir = settings.get("PORTAGE_BUILDDIR")
			build_log = settings.get("PORTAGE_LOG_FILE")

			self._failed_pkgs.append(self._failed_pkg(
				build_dir=build_dir, build_log=build_log,
				pkg=build.pkg,
				returncode=build.returncode))
			self._failed_pkg_msg(self._failed_pkgs[-1], "emerge", "for")

			self._status_display.failed = len(self._failed_pkgs)
			self._deallocate_config(build.settings)
		self._jobs -= 1
		self._status_display.running = self._jobs
		self._schedule()

	def _extract_exit(self, build):
		self._build_exit(build)

	def _task_complete(self, pkg):
		self._completed_tasks.add(pkg)
		self._unsatisfied_system_deps.discard(pkg)
		self._choose_pkg_return_early = False

	def _merge(self):

		self._add_prefetchers()
		self._add_packages()
		pkg_queue = self._pkg_queue
		failed_pkgs = self._failed_pkgs
		portage.locks._quiet = self._background
		portage.elog._emerge_elog_listener = self._elog_listener
		rval = os.EX_OK

		try:
			self._main_loop()
		finally:
			self._main_loop_cleanup()
			portage.locks._quiet = False
			portage.elog._emerge_elog_listener = None
			if failed_pkgs:
				rval = failed_pkgs[-1].returncode

		return rval

	def _main_loop_cleanup(self):
		del self._pkg_queue[:]
		self._completed_tasks.clear()
		self._deep_system_deps.clear()
		self._unsatisfied_system_deps.clear()
		self._choose_pkg_return_early = False
		self._status_display.reset()
		self._digraph = None
		self._task_queues.fetch.clear()

	def _choose_pkg(self):
		"""
		Choose a task that has all it's dependencies satisfied.
		"""

		if self._choose_pkg_return_early:
			return None

		if self._digraph is None:
			if (self._jobs or self._task_queues.merge) and \
				not ("--nodeps" in self.myopts and \
				(self._max_jobs is True or self._max_jobs > 1)):
				self._choose_pkg_return_early = True
				return None
			return self._pkg_queue.pop(0)

		if not (self._jobs or self._task_queues.merge):
			return self._pkg_queue.pop(0)

		self._prune_digraph()

		chosen_pkg = None
		later = set(self._pkg_queue)
		for pkg in self._pkg_queue:
			later.remove(pkg)
			if not self._dependent_on_scheduled_merges(pkg, later):
				chosen_pkg = pkg
				break

		if chosen_pkg is not None:
			self._pkg_queue.remove(chosen_pkg)

		if chosen_pkg is None:
			# There's no point in searching for a package to
			# choose until at least one of the existing jobs
			# completes.
			self._choose_pkg_return_early = True

		return chosen_pkg

	def _dependent_on_scheduled_merges(self, pkg, later):
		"""
		Traverse the subgraph of the given packages deep dependencies
		to see if it contains any scheduled merges.
		@param pkg: a package to check dependencies for
		@type pkg: Package
		@param later: packages for which dependence should be ignored
			since they will be merged later than pkg anyway and therefore
			delaying the merge of pkg will not result in a more optimal
			merge order
		@type later: set
		@rtype: bool
		@returns: True if the package is dependent, False otherwise.
		"""

		graph = self._digraph
		completed_tasks = self._completed_tasks

		dependent = False
		traversed_nodes = set([pkg])
		direct_deps = graph.child_nodes(pkg)
		node_stack = direct_deps
		direct_deps = frozenset(direct_deps)
		while node_stack:
			node = node_stack.pop()
			if node in traversed_nodes:
				continue
			traversed_nodes.add(node)
			if not ((node.installed and node.operation == "nomerge") or \
				(node.operation == "uninstall" and \
				node not in direct_deps) or \
				node in completed_tasks or \
				node in later):
				dependent = True
				break
			node_stack.extend(graph.child_nodes(node))

		return dependent

	def _allocate_config(self, root):
		"""
		Allocate a unique config instance for a task in order
		to prevent interference between parallel tasks.
		"""
		if self._config_pool[root]:
			temp_settings = self._config_pool[root].pop()
		else:
			temp_settings = portage.config(clone=self.pkgsettings[root])
		# Since config.setcpv() isn't guaranteed to call config.reset() due to
		# performance reasons, call it here to make sure all settings from the
		# previous package get flushed out (such as PORTAGE_LOG_FILE).
		temp_settings.reload()
		temp_settings.reset()
		return temp_settings

	def _deallocate_config(self, settings):
		self._config_pool[settings["ROOT"]].append(settings)

	def _main_loop(self):

		# Only allow 1 job max if a restart is scheduled
		# due to portage update.
		if self._is_restart_scheduled() or \
			self._opts_no_background.intersection(self.myopts):
			self._set_max_jobs(1)

		merge_queue = self._task_queues.merge

		while self._schedule():
			if self._poll_event_handlers:
				self._poll_loop()

		while True:
			self._schedule()
			if not (self._jobs or merge_queue):
				break
			if self._poll_event_handlers:
				self._poll_loop()

	def _keep_scheduling(self):
		return bool(self._pkg_queue and \
			not (self._failed_pkgs and not self._build_opts.fetchonly))

	def _schedule_tasks(self):

		# When the number of jobs drops to zero, process all waiting merges.
		if not self._jobs and self._merge_wait_queue:
			for task in self._merge_wait_queue:
				task.addExitListener(self._merge_wait_exit_handler)
				self._task_queues.merge.add(task)
			self._status_display.merges = len(self._task_queues.merge)
			self._merge_wait_scheduled.extend(self._merge_wait_queue)
			del self._merge_wait_queue[:]

		self._schedule_tasks_imp()
		self._status_display.display()

		state_change = 0
		for q in self._task_queues.values():
			if q.schedule():
				state_change += 1

		# Cancel prefetchers if they're the only reason
		# the main poll loop is still running.
		if self._failed_pkgs and not self._build_opts.fetchonly and \
			not (self._jobs or self._task_queues.merge) and \
			self._task_queues.fetch:
			self._task_queues.fetch.clear()
			state_change += 1

		if state_change:
			self._schedule_tasks_imp()
			self._status_display.display()

		return self._keep_scheduling()

	def _job_delay(self):
		"""
		@rtype: bool
		@returns: True if job scheduling should be delayed, False otherwise.
		"""

		if self._jobs and self._max_load is not None:

			current_time = time.time()

			delay = self._job_delay_factor * self._jobs ** self._job_delay_exp
			if delay > self._job_delay_max:
				delay = self._job_delay_max
			if (current_time - self._previous_job_start_time) < delay:
				return True

		return False

	def _schedule_tasks_imp(self):
		"""
		@rtype: bool
		@returns: True if state changed, False otherwise.
		"""

		state_change = 0

		while True:

			if not self._keep_scheduling():
				return bool(state_change)

			if self._choose_pkg_return_early or \
				self._merge_wait_scheduled or \
				(self._jobs and self._unsatisfied_system_deps) or \
				not self._can_add_job() or \
				self._job_delay():
				return bool(state_change)

			pkg = self._choose_pkg()
			if pkg is None:
				return bool(state_change)

			state_change += 1

			if not pkg.installed:
				self._pkg_count.curval += 1

			task = self._task(pkg)

			if pkg.installed:
				merge = PackageMerge(merge=task)
				merge.addExitListener(self._merge_exit)
				self._task_queues.merge.add(merge)

			elif pkg.built:
				self._jobs += 1
				self._previous_job_start_time = time.time()
				self._status_display.running = self._jobs
				task.addExitListener(self._extract_exit)
				self._task_queues.jobs.add(task)

			else:
				self._jobs += 1
				self._previous_job_start_time = time.time()
				self._status_display.running = self._jobs
				task.addExitListener(self._build_exit)
				self._task_queues.jobs.add(task)

		return bool(state_change)

	def _task(self, pkg):

		pkg_to_replace = None
		if pkg.operation != "uninstall":
			vardb = pkg.root_config.trees["vartree"].dbapi
			previous_cpv = vardb.match(pkg.slot_atom)
			if previous_cpv:
				previous_cpv = previous_cpv.pop()
				pkg_to_replace = self._pkg(previous_cpv,
					"installed", pkg.root_config, installed=True)

		task = MergeListItem(args_set=self._args_set,
			background=self._background, binpkg_opts=self._binpkg_opts,
			build_opts=self._build_opts,
			config_pool=self._ConfigPool(pkg.root,
			self._allocate_config, self._deallocate_config),
			emerge_opts=self.myopts,
			find_blockers=self._find_blockers(pkg), logger=self._logger,
			mtimedb=self._mtimedb, pkg=pkg, pkg_count=self._pkg_count.copy(),
			pkg_to_replace=pkg_to_replace,
			prefetcher=self._prefetchers.get(pkg),
			scheduler=self._sched_iface,
			settings=self._allocate_config(pkg.root),
			statusMessage=self._status_msg,
			world_atom=self._world_atom)

		return task

	def _failed_pkg_msg(self, failed_pkg, action, preposition):
		pkg = failed_pkg.pkg
		msg = "%s to %s %s" % \
			(bad("Failed"), action, colorize("INFORM", pkg.cpv))
		if pkg.root != "/":
			msg += " %s %s" % (preposition, pkg.root)

		log_path = self._locate_failure_log(failed_pkg)
		if log_path is not None:
			msg += ", Log file:"
		self._status_msg(msg)

		if log_path is not None:
			self._status_msg(" '%s'" % (colorize("INFORM", log_path),))

	def _status_msg(self, msg):
		"""
		Display a brief status message (no newlines) in the status display.
		This is called by tasks to provide feedback to the user. This
		delegates the resposibility of generating \r and \n control characters,
		to guarantee that lines are created or erased when necessary and
		appropriate.

		@type msg: str
		@param msg: a brief status message (no newlines allowed)
		"""
		if not self._background:
			writemsg_level("\n")
		self._status_display.displayMessage(msg)

	def _save_resume_list(self):
		"""
		Do this before verifying the ebuild Manifests since it might
		be possible for the user to use --resume --skipfirst get past
		a non-essential package with a broken digest.
		"""
		mtimedb = self._mtimedb
		mtimedb["resume"]["mergelist"] = [list(x) \
			for x in self._mergelist \
			if isinstance(x, Package) and x.operation == "merge"]

		mtimedb.commit()

	def _calc_resume_list(self):
		"""
		Use the current resume list to calculate a new one,
		dropping any packages with unsatisfied deps.
		@rtype: bool
		@returns: True if successful, False otherwise.
		"""
		print colorize("GOOD", "*** Resuming merge...")

		if self._show_list():
			if "--tree" in self.myopts:
				portage.writemsg_stdout("\n" + \
					darkgreen("These are the packages that " + \
					"would be merged, in reverse order:\n\n"))

			else:
				portage.writemsg_stdout("\n" + \
					darkgreen("These are the packages that " + \
					"would be merged, in order:\n\n"))

		show_spinner = "--quiet" not in self.myopts and \
			"--nodeps" not in self.myopts

		if show_spinner:
			print "Calculating dependencies  ",

		myparams = create_depgraph_params(self.myopts, None)
		success = False
		e = None
		try:
			success, mydepgraph, dropped_tasks = resume_depgraph(
				self.settings, self.trees, self._mtimedb, self.myopts,
				myparams, self._spinner)
		except depgraph.UnsatisfiedResumeDep, exc:
			# rename variable to avoid python-3.0 error:
			# SyntaxError: can not delete variable 'e' referenced in nested
			#              scope
			e = exc
			mydepgraph = e.depgraph
			dropped_tasks = set()

		if show_spinner:
			print "\b\b... done!"

		if e is not None:
			def unsatisfied_resume_dep_msg():
				mydepgraph.display_problems()
				out = portage.output.EOutput()
				out.eerror("One or more packages are either masked or " + \
					"have missing dependencies:")
				out.eerror("")
				indent = "  "
				show_parents = set()
				for dep in e.value:
					if dep.parent in show_parents:
						continue
					show_parents.add(dep.parent)
					if dep.atom is None:
						out.eerror(indent + "Masked package:")
						out.eerror(2 * indent + str(dep.parent))
						out.eerror("")
					else:
						out.eerror(indent + str(dep.atom) + " pulled in by:")
						out.eerror(2 * indent + str(dep.parent))
						out.eerror("")
				msg = "The resume list contains packages " + \
					"that are either masked or have " + \
					"unsatisfied dependencies. " + \
					"Please restart/continue " + \
					"the operation manually, or use --skipfirst " + \
					"to skip the first package in the list and " + \
					"any other packages that may be " + \
					"masked or have missing dependencies."
				for line in textwrap.wrap(msg, 72):
					out.eerror(line)
			self._post_mod_echo_msgs.append(unsatisfied_resume_dep_msg)
			return False

		if success and self._show_list():
			mylist = mydepgraph.altlist()
			if mylist:
				if "--tree" in self.myopts:
					mylist.reverse()
				mydepgraph.display(mylist, favorites=self._favorites)

		if not success:
			self._post_mod_echo_msgs.append(mydepgraph.display_problems)
			return False
		mydepgraph.display_problems()

		mylist = mydepgraph.altlist()
		mydepgraph.break_refs(mylist)
		mydepgraph.break_refs(dropped_tasks)
		self._mergelist = mylist
		self._set_digraph(mydepgraph.schedulerGraph())

		msg_width = 75
		for task in dropped_tasks:
			if not (isinstance(task, Package) and task.operation == "merge"):
				continue
			pkg = task
			msg = "emerge --keep-going:" + \
				" %s" % (pkg.cpv,)
			if pkg.root != "/":
				msg += " for %s" % (pkg.root,)
			msg += " dropped due to unsatisfied dependency."
			for line in textwrap.wrap(msg, msg_width):
				eerror(line, phase="other", key=pkg.cpv)
			settings = self.pkgsettings[pkg.root]
			# Ensure that log collection from $T is disabled inside
			# elog_process(), since any logs that might exist are
			# not valid here.
			settings.pop("T", None)
			portage.elog.elog_process(pkg.cpv, settings)
			self._failed_pkgs_all.append(self._failed_pkg(pkg=pkg))

		return True

	def _show_list(self):
		myopts = self.myopts
		if "--quiet" not in myopts and \
			("--ask" in myopts or "--tree" in myopts or \
			"--verbose" in myopts):
			return True
		return False

	def _world_atom(self, pkg):
		"""
		Add the package to the world file, but only if
		it's supposed to be added. Otherwise, do nothing.
		"""

		if set(("--buildpkgonly", "--fetchonly",
			"--fetch-all-uri",
			"--oneshot", "--onlydeps",
			"--pretend")).intersection(self.myopts):
			return

		if pkg.root != self.target_root:
			return

		args_set = self._args_set
		if not args_set.findAtomForPackage(pkg):
			return

		logger = self._logger
		pkg_count = self._pkg_count
		root_config = pkg.root_config
		world_set = root_config.sets["world"]
		world_locked = False
		if hasattr(world_set, "lock"):
			world_set.lock()
			world_locked = True

		try:
			if hasattr(world_set, "load"):
				world_set.load() # maybe it's changed on disk

			atom = create_world_atom(pkg, args_set, root_config)
			if atom:
				if hasattr(world_set, "add"):
					self._status_msg(('Recording %s in "world" ' + \
						'favorites file...') % atom)
					logger.log(" === (%s of %s) Updating world file (%s)" % \
						(pkg_count.curval, pkg_count.maxval, pkg.cpv))
					world_set.add(atom)
				else:
					writemsg_level('\n!!! Unable to record %s in "world"\n' % \
						(atom,), level=logging.WARN, noiselevel=-1)
		finally:
			if world_locked:
				world_set.unlock()

	def _pkg(self, cpv, type_name, root_config, installed=False):
		"""
		Get a package instance from the cache, or create a new
		one if necessary. Raises KeyError from aux_get if it
		failures for some reason (package does not exist or is
		corrupt).
		"""
		operation = "merge"
		if installed:
			operation = "nomerge"

		if self._digraph is not None:
			# Reuse existing instance when available.
			pkg = self._digraph.get(
				(type_name, root_config.root, cpv, operation))
			if pkg is not None:
				return pkg

		tree_type = depgraph.pkg_tree_map[type_name]
		db = root_config.trees[tree_type].dbapi
		db_keys = list(self.trees[root_config.root][
			tree_type].dbapi._aux_cache_keys)
		metadata = izip(db_keys, db.aux_get(cpv, db_keys))
		pkg = Package(cpv=cpv, metadata=metadata,
			root_config=root_config, installed=installed)
		if type_name == "ebuild":
			settings = self.pkgsettings[root_config.root]
			settings.setcpv(pkg)
			pkg.metadata["USE"] = settings["PORTAGE_USE"]
			pkg.metadata['CHOST'] = settings.get('CHOST', '')

		return pkg

class MetadataRegen(PollScheduler):

	def __init__(self, portdb, max_jobs=None, max_load=None):
		PollScheduler.__init__(self)
		self._portdb = portdb

		if max_jobs is None:
			max_jobs = 1

		self._max_jobs = max_jobs
		self._max_load = max_load
		self._sched_iface = self._sched_iface_class(
			register=self._register,
			schedule=self._schedule_wait,
			unregister=self._unregister)

		self._valid_pkgs = set()
		self._process_iter = self._iter_metadata_processes()
		self.returncode = os.EX_OK
		self._error_count = 0

	def _iter_metadata_processes(self):
		portdb = self._portdb
		valid_pkgs = self._valid_pkgs
		every_cp = portdb.cp_all()
		every_cp.sort(reverse=True)

		while every_cp:
			cp = every_cp.pop()
			portage.writemsg_stdout("Processing %s\n" % cp)
			cpv_list = portdb.cp_list(cp)
			for cpv in cpv_list:
				valid_pkgs.add(cpv)
				ebuild_path, repo_path = portdb.findname2(cpv)
				metadata_process = portdb._metadata_process(
					cpv, ebuild_path, repo_path)
				if metadata_process is None:
					continue
				yield metadata_process

	def run(self):

		portdb = self._portdb
		from portage.cache.cache_errors import CacheError
		dead_nodes = {}

		for mytree in portdb.porttrees:
			try:
				dead_nodes[mytree] = set(portdb.auxdb[mytree].iterkeys())
			except CacheError, e:
				portage.writemsg("Error listing cache entries for " + \
					"'%s': %s, continuing...\n" % (mytree, e), noiselevel=-1)
				del e
				dead_nodes = None
				break

		while self._schedule():
			self._poll_loop()

		while self._jobs:
			self._poll_loop()

		if dead_nodes:
			for y in self._valid_pkgs:
				for mytree in portdb.porttrees:
					if portdb.findname2(y, mytree=mytree)[0]:
						dead_nodes[mytree].discard(y)

			for mytree, nodes in dead_nodes.iteritems():
				auxdb = portdb.auxdb[mytree]
				for y in nodes:
					try:
						del auxdb[y]
					except (KeyError, CacheError):
						pass

	def _schedule_tasks(self):
		"""
		@rtype: bool
		@returns: True if there may be remaining tasks to schedule,
			False otherwise.
		"""
		while self._can_add_job():
			try:
				metadata_process = self._process_iter.next()
			except StopIteration:
				return False

			self._jobs += 1
			metadata_process.scheduler = self._sched_iface
			metadata_process.addExitListener(self._metadata_exit)
			metadata_process.start()
		return True

	def _metadata_exit(self, metadata_process):
		self._jobs -= 1
		if metadata_process.returncode != os.EX_OK:
			self.returncode = 1
			self._error_count += 1
			self._valid_pkgs.discard(metadata_process.cpv)
			portage.writemsg("Error processing %s, continuing...\n" % \
				(metadata_process.cpv,))
		self._schedule()

class UninstallFailure(portage.exception.PortageException):
	"""
	An instance of this class is raised by unmerge() when
	an uninstallation fails.
	"""
	status = 1
	def __init__(self, *pargs):
		portage.exception.PortageException.__init__(self, pargs)
		if pargs:
			self.status = pargs[0]

def unmerge(root_config, myopts, unmerge_action,
	unmerge_files, ldpath_mtimes, autoclean=0,
	clean_world=1, clean_delay=1, ordered=0, raise_on_error=0,
	scheduler=None, writemsg_level=portage.util.writemsg_level):

	quiet = "--quiet" in myopts
	settings = root_config.settings
	sets = root_config.sets
	vartree = root_config.trees["vartree"]
	candidate_catpkgs=[]
	global_unmerge=0
	xterm_titles = "notitles" not in settings.features
	out = portage.output.EOutput()
	pkg_cache = {}
	db_keys = list(vartree.dbapi._aux_cache_keys)

	def _pkg(cpv):
		pkg = pkg_cache.get(cpv)
		if pkg is None:
			pkg = Package(cpv=cpv, installed=True,
				metadata=izip(db_keys, vartree.dbapi.aux_get(cpv, db_keys)),
				root_config=root_config,
				type_name="installed")
			pkg_cache[cpv] = pkg
		return pkg

	vdb_path = os.path.join(settings["ROOT"], portage.VDB_PATH)
	try:
		# At least the parent needs to exist for the lock file.
		portage.util.ensure_dirs(vdb_path)
	except portage.exception.PortageException:
		pass
	vdb_lock = None
	try:
		if os.access(vdb_path, os.W_OK):
			vdb_lock = portage.locks.lockdir(vdb_path)
		realsyslist = sets["system"].getAtoms()
		syslist = []
		for x in realsyslist:
			mycp = portage.dep_getkey(x)
			if mycp in settings.getvirtuals():
				providers = []
				for provider in settings.getvirtuals()[mycp]:
					if vartree.dbapi.match(provider):
						providers.append(provider)
				if len(providers) == 1:
					syslist.extend(providers)
			else:
				syslist.append(mycp)
	
		mysettings = portage.config(clone=settings)
	
		if not unmerge_files:
			if unmerge_action == "unmerge":
				print
				print bold("emerge unmerge") + " can only be used with specific package names"
				print
				return 0
			else:
				global_unmerge = 1
	
		localtree = vartree
		# process all arguments and add all
		# valid db entries to candidate_catpkgs
		if global_unmerge:
			if not unmerge_files:
				candidate_catpkgs.extend(vartree.dbapi.cp_all())
		else:
			#we've got command-line arguments
			if not unmerge_files:
				print "\nNo packages to unmerge have been provided.\n"
				return 0
			for x in unmerge_files:
				arg_parts = x.split('/')
				if x[0] not in [".","/"] and \
					arg_parts[-1][-7:] != ".ebuild":
					#possible cat/pkg or dep; treat as such
					candidate_catpkgs.append(x)
				elif unmerge_action in ["prune","clean"]:
					print "\n!!! Prune and clean do not accept individual" + \
						" ebuilds as arguments;\n    skipping.\n"
					continue
				else:
					# it appears that the user is specifying an installed
					# ebuild and we're in "unmerge" mode, so it's ok.
					if not os.path.exists(x):
						print "\n!!! The path '"+x+"' doesn't exist.\n"
						return 0
	
					absx   = os.path.abspath(x)
					sp_absx = absx.split("/")
					if sp_absx[-1][-7:] == ".ebuild":
						del sp_absx[-1]
						absx = "/".join(sp_absx)
	
					sp_absx_len = len(sp_absx)
	
					vdb_path = os.path.join(settings["ROOT"], portage.VDB_PATH)
					vdb_len  = len(vdb_path)
	
					sp_vdb     = vdb_path.split("/")
					sp_vdb_len = len(sp_vdb)
	
					if not os.path.exists(absx+"/CONTENTS"):
						print "!!! Not a valid db dir: "+str(absx)
						return 0
	
					if sp_absx_len <= sp_vdb_len:
						# The Path is shorter... so it can't be inside the vdb.
						print sp_absx
						print absx
						print "\n!!!",x,"cannot be inside "+ \
							vdb_path+"; aborting.\n"
						return 0
	
					for idx in range(0,sp_vdb_len):
						if idx >= sp_absx_len or sp_vdb[idx] != sp_absx[idx]:
							print sp_absx
							print absx
							print "\n!!!", x, "is not inside "+\
								vdb_path+"; aborting.\n"
							return 0
	
					print "="+"/".join(sp_absx[sp_vdb_len:])
					candidate_catpkgs.append(
						"="+"/".join(sp_absx[sp_vdb_len:]))
	
		newline=""
		if (not "--quiet" in myopts):
			newline="\n"
		if settings["ROOT"] != "/":
			writemsg_level(darkgreen(newline+ \
				">>> Using system located in ROOT tree %s\n" % \
				settings["ROOT"]))

		if (("--pretend" in myopts) or ("--ask" in myopts)) and \
			not ("--quiet" in myopts):
			writemsg_level(darkgreen(newline+\
				">>> These are the packages that would be unmerged:\n"))

		# Preservation of order is required for --depclean and --prune so
		# that dependencies are respected. Use all_selected to eliminate
		# duplicate packages since the same package may be selected by
		# multiple atoms.
		pkgmap = []
		all_selected = set()
		for x in candidate_catpkgs:
			# cycle through all our candidate deps and determine
			# what will and will not get unmerged
			try:
				mymatch = vartree.dbapi.match(x)
			except portage.exception.AmbiguousPackageName, errpkgs:
				print "\n\n!!! The short ebuild name \"" + \
					x + "\" is ambiguous.  Please specify"
				print "!!! one of the following fully-qualified " + \
					"ebuild names instead:\n"
				for i in errpkgs[0]:
					print "    " + green(i)
				print
				sys.exit(1)
	
			if not mymatch and x[0] not in "<>=~":
				mymatch = localtree.dep_match(x)
			if not mymatch:
				portage.writemsg("\n--- Couldn't find '%s' to %s.\n" % \
					(x, unmerge_action), noiselevel=-1)
				continue

			pkgmap.append(
				{"protected": set(), "selected": set(), "omitted": set()})
			mykey = len(pkgmap) - 1
			if unmerge_action=="unmerge":
					for y in mymatch:
						if y not in all_selected:
							pkgmap[mykey]["selected"].add(y)
							all_selected.add(y)
			elif unmerge_action == "prune":
				if len(mymatch) == 1:
					continue
				best_version = mymatch[0]
				best_slot = vartree.getslot(best_version)
				best_counter = vartree.dbapi.cpv_counter(best_version)
				for mypkg in mymatch[1:]:
					myslot = vartree.getslot(mypkg)
					mycounter = vartree.dbapi.cpv_counter(mypkg)
					if (myslot == best_slot and mycounter > best_counter) or \
						mypkg == portage.best([mypkg, best_version]):
						if myslot == best_slot:
							if mycounter < best_counter:
								# On slot collision, keep the one with the
								# highest counter since it is the most
								# recently installed.
								continue
						best_version = mypkg
						best_slot = myslot
						best_counter = mycounter
				pkgmap[mykey]["protected"].add(best_version)
				pkgmap[mykey]["selected"].update(mypkg for mypkg in mymatch \
					if mypkg != best_version and mypkg not in all_selected)
				all_selected.update(pkgmap[mykey]["selected"])
			else:
				# unmerge_action == "clean"
				slotmap={}
				for mypkg in mymatch:
					if unmerge_action == "clean":
						myslot = localtree.getslot(mypkg)
					else:
						# since we're pruning, we don't care about slots
						# and put all the pkgs in together
						myslot = 0
					if myslot not in slotmap:
						slotmap[myslot] = {}
					slotmap[myslot][localtree.dbapi.cpv_counter(mypkg)] = mypkg

				for mypkg in vartree.dbapi.cp_list(
					portage.dep_getkey(mymatch[0])):
					myslot = vartree.getslot(mypkg)
					if myslot not in slotmap:
						slotmap[myslot] = {}
					slotmap[myslot][vartree.dbapi.cpv_counter(mypkg)] = mypkg

				for myslot in slotmap:
					counterkeys = slotmap[myslot].keys()
					if not counterkeys:
						continue
					counterkeys.sort()
					pkgmap[mykey]["protected"].add(
						slotmap[myslot][counterkeys[-1]])
					del counterkeys[-1]

					for counter in counterkeys[:]:
						mypkg = slotmap[myslot][counter]
						if mypkg not in mymatch:
							counterkeys.remove(counter)
							pkgmap[mykey]["protected"].add(
								slotmap[myslot][counter])

					#be pretty and get them in order of merge:
					for ckey in counterkeys:
						mypkg = slotmap[myslot][ckey]
						if mypkg not in all_selected:
							pkgmap[mykey]["selected"].add(mypkg)
							all_selected.add(mypkg)
					# ok, now the last-merged package
					# is protected, and the rest are selected
		numselected = len(all_selected)
		if global_unmerge and not numselected:
			portage.writemsg_stdout("\n>>> No outdated packages were found on your system.\n")
			return 0
	
		if not numselected:
			portage.writemsg_stdout(
				"\n>>> No packages selected for removal by " + \
				unmerge_action + "\n")
			return 0
	finally:
		if vdb_lock:
			vartree.dbapi.flush_cache()
			portage.locks.unlockdir(vdb_lock)
	
	from portage.sets.base import EditablePackageSet
	
	# generate a list of package sets that are directly or indirectly listed in "world",
	# as there is no persistent list of "installed" sets
	installed_sets = ["world"]
	stop = False
	pos = 0
	while not stop:
		stop = True
		pos = len(installed_sets)
		for s in installed_sets[pos - 1:]:
			if s not in sets:
				continue
			candidates = [x[len(SETPREFIX):] for x in sets[s].getNonAtoms() if x.startswith(SETPREFIX)]
			if candidates:
				stop = False
				installed_sets += candidates
	installed_sets = [x for x in installed_sets if x not in root_config.setconfig.active]
	del stop, pos

	# we don't want to unmerge packages that are still listed in user-editable package sets
	# listed in "world" as they would be remerged on the next update of "world" or the 
	# relevant package sets.
	unknown_sets = set()
	for cp in xrange(len(pkgmap)):
		for cpv in pkgmap[cp]["selected"].copy():
			try:
				pkg = _pkg(cpv)
			except KeyError:
				# It could have been uninstalled
				# by a concurrent process.
				continue

			if unmerge_action != "clean" and \
				root_config.root == "/" and \
				portage.match_from_list(
				portage.const.PORTAGE_PACKAGE_ATOM, [pkg]):
				msg = ("Not unmerging package %s since there is no valid " + \
				"reason for portage to unmerge itself.") % (pkg.cpv,)
				for line in textwrap.wrap(msg, 75):
					out.eerror(line)
				# adjust pkgmap so the display output is correct
				pkgmap[cp]["selected"].remove(cpv)
				all_selected.remove(cpv)
				pkgmap[cp]["protected"].add(cpv)
				continue

			parents = []
			for s in installed_sets:
				# skip sets that the user requested to unmerge, and skip world 
				# unless we're unmerging a package set (as the package would be 
				# removed from "world" later on)
				if s in root_config.setconfig.active or (s == "world" and not root_config.setconfig.active):
					continue

				if s not in sets:
					if s in unknown_sets:
						continue
					unknown_sets.add(s)
					out = portage.output.EOutput()
					out.eerror(("Unknown set '@%s' in " + \
						"%svar/lib/portage/world_sets") % \
						(s, root_config.root))
					continue

				# only check instances of EditablePackageSet as other classes are generally used for
				# special purposes and can be ignored here (and are usually generated dynamically, so the
				# user can't do much about them anyway)
				if isinstance(sets[s], EditablePackageSet):

					# This is derived from a snippet of code in the
					# depgraph._iter_atoms_for_pkg() method.
					for atom in sets[s].iterAtomsForPackage(pkg):
						inst_matches = vartree.dbapi.match(atom)
						inst_matches.reverse() # descending order
						higher_slot = None
						for inst_cpv in inst_matches:
							try:
								inst_pkg = _pkg(inst_cpv)
							except KeyError:
								# It could have been uninstalled
								# by a concurrent process.
								continue

							if inst_pkg.cp != atom.cp:
								continue
							if pkg >= inst_pkg:
								# This is descending order, and we're not
								# interested in any versions <= pkg given.
								break
							if pkg.slot_atom != inst_pkg.slot_atom:
								higher_slot = inst_pkg
								break
						if higher_slot is None:
							parents.append(s)
							break
			if parents:
				#print colorize("WARN", "Package %s is going to be unmerged," % cpv)
				#print colorize("WARN", "but still listed in the following package sets:")
				#print "    %s\n" % ", ".join(parents)
				print colorize("WARN", "Not unmerging package %s as it is" % cpv)
				print colorize("WARN", "still referenced by the following package sets:")
				print "    %s\n" % ", ".join(parents)
				# adjust pkgmap so the display output is correct
				pkgmap[cp]["selected"].remove(cpv)
				all_selected.remove(cpv)
				pkgmap[cp]["protected"].add(cpv)
	
	del installed_sets

	numselected = len(all_selected)
	if not numselected:
		writemsg_level(
			"\n>>> No packages selected for removal by " + \
			unmerge_action + "\n")
		return 0

	# Unmerge order only matters in some cases
	if not ordered:
		unordered = {}
		for d in pkgmap:
			selected = d["selected"]
			if not selected:
				continue
			cp = portage.cpv_getkey(iter(selected).next())
			cp_dict = unordered.get(cp)
			if cp_dict is None:
				cp_dict = {}
				unordered[cp] = cp_dict
				for k in d:
					cp_dict[k] = set()
			for k, v in d.iteritems():
				cp_dict[k].update(v)
		pkgmap = [unordered[cp] for cp in sorted(unordered)]

	for x in xrange(len(pkgmap)):
		selected = pkgmap[x]["selected"]
		if not selected:
			continue
		for mytype, mylist in pkgmap[x].iteritems():
			if mytype == "selected":
				continue
			mylist.difference_update(all_selected)
		cp = portage.cpv_getkey(iter(selected).next())
		for y in localtree.dep_match(cp):
			if y not in pkgmap[x]["omitted"] and \
				y not in pkgmap[x]["selected"] and \
				y not in pkgmap[x]["protected"] and \
				y not in all_selected:
				pkgmap[x]["omitted"].add(y)
		if global_unmerge and not pkgmap[x]["selected"]:
			#avoid cluttering the preview printout with stuff that isn't getting unmerged
			continue
		if not (pkgmap[x]["protected"] or pkgmap[x]["omitted"]) and cp in syslist:
			writemsg_level(colorize("BAD","\a\n\n!!! " + \
				"'%s' is part of your system profile.\n" % cp),
				level=logging.WARNING, noiselevel=-1)
			writemsg_level(colorize("WARN","\a!!! Unmerging it may " + \
				"be damaging to your system.\n\n"),
				level=logging.WARNING, noiselevel=-1)
			if clean_delay and "--pretend" not in myopts and "--ask" not in myopts:
				countdown(int(settings["EMERGE_WARNING_DELAY"]),
					colorize("UNMERGE_WARN", "Press Ctrl-C to Stop"))
		if not quiet:
			writemsg_level("\n %s\n" % (bold(cp),), noiselevel=-1)
		else:
			writemsg_level(bold(cp) + ": ", noiselevel=-1)
		for mytype in ["selected","protected","omitted"]:
			if not quiet:
				writemsg_level((mytype + ": ").rjust(14), noiselevel=-1)
			if pkgmap[x][mytype]:
				sorted_pkgs = [portage.catpkgsplit(mypkg)[1:] for mypkg in pkgmap[x][mytype]]
				sorted_pkgs.sort(key=cmp_sort_key(portage.pkgcmp))
				for pn, ver, rev in sorted_pkgs:
					if rev == "r0":
						myversion = ver
					else:
						myversion = ver + "-" + rev
					if mytype == "selected":
						writemsg_level(
							colorize("UNMERGE_WARN", myversion + " "),
							noiselevel=-1)
					else:
						writemsg_level(
							colorize("GOOD", myversion + " "), noiselevel=-1)
			else:
				writemsg_level("none ", noiselevel=-1)
			if not quiet:
				writemsg_level("\n", noiselevel=-1)
		if quiet:
			writemsg_level("\n", noiselevel=-1)

	writemsg_level("\n>>> " + colorize("UNMERGE_WARN", "'Selected'") + \
		" packages are slated for removal.\n")
	writemsg_level(">>> " + colorize("GOOD", "'Protected'") + \
			" and " + colorize("GOOD", "'omitted'") + \
			" packages will not be removed.\n\n")

	if "--pretend" in myopts:
		#we're done... return
		return 0
	if "--ask" in myopts:
		if userquery("Would you like to unmerge these packages?")=="No":
			# enter pretend mode for correct formatting of results
			myopts["--pretend"] = True
			print
			print "Quitting."
			print
			return 0
	#the real unmerging begins, after a short delay....
	if clean_delay and not autoclean:
		countdown(int(settings["CLEAN_DELAY"]), ">>> Unmerging")

	for x in xrange(len(pkgmap)):
		for y in pkgmap[x]["selected"]:
			writemsg_level(">>> Unmerging "+y+"...\n", noiselevel=-1)
			emergelog(xterm_titles, "=== Unmerging... ("+y+")")
			mysplit = y.split("/")
			#unmerge...
			retval = portage.unmerge(mysplit[0], mysplit[1], settings["ROOT"],
				mysettings, unmerge_action not in ["clean","prune"],
				vartree=vartree, ldpath_mtimes=ldpath_mtimes,
				scheduler=scheduler)

			if retval != os.EX_OK:
				emergelog(xterm_titles, " !!! unmerge FAILURE: "+y)
				if raise_on_error:
					raise UninstallFailure(retval)
				sys.exit(retval)
			else:
				if clean_world and hasattr(sets["world"], "cleanPackage"):
					sets["world"].cleanPackage(vartree.dbapi, y)
				emergelog(xterm_titles, " >>> unmerge success: "+y)
	if clean_world and hasattr(sets["world"], "remove"):
		for s in root_config.setconfig.active:
			sets["world"].remove(SETPREFIX+s)
	return 1

def chk_updated_info_files(root, infodirs, prev_mtimes, retval):

	if os.path.exists("/usr/bin/install-info"):
		out = portage.output.EOutput()
		regen_infodirs=[]
		for z in infodirs:
			if z=='':
				continue
			inforoot=normpath(root+z)
			if os.path.isdir(inforoot):
				infomtime = long(os.stat(inforoot).st_mtime)
				if inforoot not in prev_mtimes or \
					prev_mtimes[inforoot] != infomtime:
						regen_infodirs.append(inforoot)

		if not regen_infodirs:
			portage.writemsg_stdout("\n")
			out.einfo("GNU info directory index is up-to-date.")
		else:
			portage.writemsg_stdout("\n")
			out.einfo("Regenerating GNU info directory index...")

			dir_extensions = ("", ".gz", ".bz2")
			icount=0
			badcount=0
			errmsg = ""
			for inforoot in regen_infodirs:
				if inforoot=='':
					continue

				if not os.path.isdir(inforoot) or \
					not os.access(inforoot, os.W_OK):
					continue

				file_list = os.listdir(inforoot)
				file_list.sort()
				dir_file = os.path.join(inforoot, "dir")
				moved_old_dir = False
				processed_count = 0
				for x in file_list:
					if x.startswith(".") or \
						os.path.isdir(os.path.join(inforoot, x)):
						continue
					if x.startswith("dir"):
						skip = False
						for ext in dir_extensions:
							if x == "dir" + ext or \
								x == "dir" + ext + ".old":
								skip = True
								break
						if skip:
							continue
					if processed_count == 0:
						for ext in dir_extensions:
							try:
								os.rename(dir_file + ext, dir_file + ext + ".old")
								moved_old_dir = True
							except EnvironmentError, e:
								if e.errno != errno.ENOENT:
									raise
								del e
					processed_count += 1
					myso=commands.getstatusoutput("LANG=C LANGUAGE=C /usr/bin/install-info --dir-file="+inforoot+"/dir "+inforoot+"/"+x)[1]
					existsstr="already exists, for file `"
					if myso!="":
						if re.search(existsstr,myso):
							# Already exists... Don't increment the count for this.
							pass
						elif myso[:44]=="install-info: warning: no info dir entry in ":
							# This info file doesn't contain a DIR-header: install-info produces this
							# (harmless) warning (the --quiet switch doesn't seem to work).
							# Don't increment the count for this.
							pass
						else:
							badcount=badcount+1
							errmsg += myso + "\n"
					icount=icount+1

				if moved_old_dir and not os.path.exists(dir_file):
					# We didn't generate a new dir file, so put the old file
					# back where it was originally found.
					for ext in dir_extensions:
						try:
							os.rename(dir_file + ext + ".old", dir_file + ext)
						except EnvironmentError, e:
							if e.errno != errno.ENOENT:
								raise
							del e

				# Clean dir.old cruft so that they don't prevent
				# unmerge of otherwise empty directories.
				for ext in dir_extensions:
					try:
						os.unlink(dir_file + ext + ".old")
					except EnvironmentError, e:
						if e.errno != errno.ENOENT:
							raise
						del e

				#update mtime so we can potentially avoid regenerating.
				prev_mtimes[inforoot] = long(os.stat(inforoot).st_mtime)

			if badcount:
				out.eerror("Processed %d info files; %d errors." % \
					(icount, badcount))
				writemsg_level(errmsg, level=logging.ERROR, noiselevel=-1)
			else:
				if icount > 0:
					out.einfo("Processed %d info files." % (icount,))


def display_news_notification(root_config, myopts):
	target_root = root_config.root
	trees = root_config.trees
	settings = trees["vartree"].settings
	portdb = trees["porttree"].dbapi
	vardb = trees["vartree"].dbapi
	NEWS_PATH = os.path.join("metadata", "news")
	UNREAD_PATH = os.path.join(target_root, NEWS_LIB_PATH, "news")
	newsReaderDisplay = False
	update = "--pretend" not in myopts

	for repo in portdb.getRepositories():
		unreadItems = checkUpdatedNewsItems(
			portdb, vardb, NEWS_PATH, UNREAD_PATH, repo, update=update)
		if unreadItems:
			if not newsReaderDisplay:
				newsReaderDisplay = True
				print
			print colorize("WARN", " * IMPORTANT:"),
			print "%s news items need reading for repository '%s'." % (unreadItems, repo)
			
	
	if newsReaderDisplay:
		print colorize("WARN", " *"),
		print "Use " + colorize("GOOD", "eselect news") + " to read news items."
		print

def display_preserved_libs(vardbapi):
	MAX_DISPLAY = 3

	# Ensure the registry is consistent with existing files.
	vardbapi.plib_registry.pruneNonExisting()

	if vardbapi.plib_registry.hasEntries():
		print
		print colorize("WARN", "!!!") + " existing preserved libs:"
		plibdata = vardbapi.plib_registry.getPreservedLibs()
		linkmap = vardbapi.linkmap
		consumer_map = {}
		owners = {}
		linkmap_broken = False

		try:
			linkmap.rebuild()
		except portage.exception.CommandNotFound, e:
			writemsg_level("!!! Command Not Found: %s\n" % (e,),
				level=logging.ERROR, noiselevel=-1)
			del e
			linkmap_broken = True
		else:
			search_for_owners = set()
			for cpv in plibdata:
				internal_plib_keys = set(linkmap._obj_key(f) \
					for f in plibdata[cpv])
				for f in plibdata[cpv]:
					if f in consumer_map:
						continue
					consumers = []
					for c in linkmap.findConsumers(f):
						# Filter out any consumers that are also preserved libs
						# belonging to the same package as the provider.
						if linkmap._obj_key(c) not in internal_plib_keys:
							consumers.append(c)
					consumers.sort()
					consumer_map[f] = consumers
					search_for_owners.update(consumers[:MAX_DISPLAY+1])

			owners = vardbapi._owners.getFileOwnerMap(search_for_owners)

		for cpv in plibdata:
			print colorize("WARN", ">>>") + " package: %s" % cpv
			samefile_map = {}
			for f in plibdata[cpv]:
				obj_key = linkmap._obj_key(f)
				alt_paths = samefile_map.get(obj_key)
				if alt_paths is None:
					alt_paths = set()
					samefile_map[obj_key] = alt_paths
				alt_paths.add(f)

			for alt_paths in samefile_map.itervalues():
				alt_paths = sorted(alt_paths)
				for p in alt_paths:
					print colorize("WARN", " * ") + " - %s" % (p,)
				f = alt_paths[0]
				consumers = consumer_map.get(f, [])
				for c in consumers[:MAX_DISPLAY]:
					print colorize("WARN", " * ") + "     used by %s (%s)" % \
						(c, ", ".join(x.mycpv for x in owners.get(c, [])))
				if len(consumers) == MAX_DISPLAY + 1:
					print colorize("WARN", " * ") + "     used by %s (%s)" % \
						(consumers[MAX_DISPLAY], ", ".join(x.mycpv \
						for x in owners.get(consumers[MAX_DISPLAY], [])))
				elif len(consumers) > MAX_DISPLAY:
					print colorize("WARN", " * ") + "     used by %d other files" % (len(consumers) - MAX_DISPLAY)
		print "Use " + colorize("GOOD", "emerge @preserved-rebuild") + " to rebuild packages using these libraries"


def _flush_elog_mod_echo():
	"""
	Dump the mod_echo output now so that our other
	notifications are shown last.
	@rtype: bool
	@returns: True if messages were shown, False otherwise.
	"""
	messages_shown = False
	try:
		from portage.elog import mod_echo
	except ImportError:
		pass # happens during downgrade to a version without the module
	else:
		messages_shown = bool(mod_echo._items)
		mod_echo.finalize()
	return messages_shown

def post_emerge(root_config, myopts, mtimedb, retval):
	"""
	Misc. things to run at the end of a merge session.
	
	Update Info Files
	Update Config Files
	Update News Items
	Commit mtimeDB
	Display preserved libs warnings
	Exit Emerge

	@param trees: A dictionary mapping each ROOT to it's package databases
	@type trees: dict
	@param mtimedb: The mtimeDB to store data needed across merge invocations
	@type mtimedb: MtimeDB class instance
	@param retval: Emerge's return value
	@type retval: Int
	@rype: None
	@returns:
	1.  Calls sys.exit(retval)
	"""

	target_root = root_config.root
	trees = { target_root : root_config.trees }
	vardbapi = trees[target_root]["vartree"].dbapi
	settings = vardbapi.settings
	info_mtimes = mtimedb["info"]

	# Load the most current variables from ${ROOT}/etc/profile.env
	settings.unlock()
	settings.reload()
	settings.regenerate()
	settings.lock()

	config_protect = settings.get("CONFIG_PROTECT","").split()
	infodirs = settings.get("INFOPATH","").split(":") + \
		settings.get("INFODIR","").split(":")

	os.chdir("/")

	if retval == os.EX_OK:
		exit_msg = " *** exiting successfully."
	else:
		exit_msg = " *** exiting unsuccessfully with status '%s'." % retval
	emergelog("notitles" not in settings.features, exit_msg)

	_flush_elog_mod_echo()

	counter_hash = settings.get("PORTAGE_COUNTER_HASH")
	if "--pretend" in myopts or (counter_hash is not None and \
		counter_hash == vardbapi._counter_hash()):
		display_news_notification(root_config, myopts)
		# If vdb state has not changed then there's nothing else to do.
		sys.exit(retval)

	vdb_path = os.path.join(target_root, portage.VDB_PATH)
	portage.util.ensure_dirs(vdb_path)
	vdb_lock = None
	if os.access(vdb_path, os.W_OK) and not "--pretend" in myopts:
		vdb_lock = portage.locks.lockdir(vdb_path)

	if vdb_lock:
		try:
			if "noinfo" not in settings.features:
				chk_updated_info_files(target_root,
					infodirs, info_mtimes, retval)
			mtimedb.commit()
		finally:
			if vdb_lock:
				portage.locks.unlockdir(vdb_lock)

	chk_updated_cfg_files(target_root, config_protect)
	
	display_news_notification(root_config, myopts)
	if retval in (None, os.EX_OK) or (not "--pretend" in myopts):
		display_preserved_libs(vardbapi)	

	sys.exit(retval)


def chk_updated_cfg_files(target_root, config_protect):
	if config_protect:
		#number of directories with some protect files in them
		procount=0
		for x in config_protect:
			x = os.path.join(target_root, x.lstrip(os.path.sep))
			if not os.access(x, os.W_OK):
				# Avoid Permission denied errors generated
				# later by `find`.
				continue
			try:
				mymode = os.lstat(x).st_mode
			except OSError:
				continue
			if stat.S_ISLNK(mymode):
				# We want to treat it like a directory if it
				# is a symlink to an existing directory.
				try:
					real_mode = os.stat(x).st_mode
					if stat.S_ISDIR(real_mode):
						mymode = real_mode
				except OSError:
					pass
			if stat.S_ISDIR(mymode):
				mycommand = "find '%s' -name '.*' -type d -prune -o -name '._cfg????_*'" % x
			else:
				mycommand = "find '%s' -maxdepth 1 -name '._cfg????_%s'" % \
					os.path.split(x.rstrip(os.path.sep))
			mycommand += " ! -name '.*~' ! -iname '.*.bak' -print0"
			a = commands.getstatusoutput(mycommand)
			if a[0] != 0:
				sys.stderr.write(" %s error scanning '%s': " % (bad("*"), x))
				sys.stderr.flush()
				# Show the error message alone, sending stdout to /dev/null.
				os.system(mycommand + " 1>/dev/null")
			else:
				files = a[1].split('\0')
				# split always produces an empty string as the last element
				if files and not files[-1]:
					del files[-1]
				if files:
					procount += 1
					print "\n"+colorize("WARN", " * IMPORTANT:"),
					if stat.S_ISDIR(mymode):
						 print "%d config files in '%s' need updating." % \
							(len(files), x)
					else:
						 print "config file '%s' needs updating." % x

		if procount:
			print " "+yellow("*")+" See the "+colorize("INFORM","CONFIGURATION FILES")+ \
				" section of the " + bold("emerge")
			print " "+yellow("*")+" man page to learn how to update config files."

def checkUpdatedNewsItems(portdb, vardb, NEWS_PATH, UNREAD_PATH, repo_id,
	update=False):
	"""
	Examines news items in repodir + '/' + NEWS_PATH and attempts to find unread items
	Returns the number of unread (yet relevent) items.
	
	@param portdb: a portage tree database
	@type portdb: pordbapi
	@param vardb: an installed package database
	@type vardb: vardbapi
	@param NEWS_PATH:
	@type NEWS_PATH:
	@param UNREAD_PATH:
	@type UNREAD_PATH:
	@param repo_id:
	@type repo_id:
	@rtype: Integer
	@returns:
	1.  The number of unread but relevant news items.
	
	"""
	from portage.news import NewsManager
	manager = NewsManager(portdb, vardb, NEWS_PATH, UNREAD_PATH)
	return manager.getUnreadItems( repo_id, update=update )

def insert_category_into_atom(atom, category):
	alphanum = re.search(r'\w', atom)
	if alphanum:
		ret = atom[:alphanum.start()] + "%s/" % category + \
			atom[alphanum.start():]
	else:
		ret = None
	return ret

def is_valid_package_atom(x):
	if "/" not in x:
		alphanum = re.search(r'\w', x)
		if alphanum:
			x = x[:alphanum.start()] + "cat/" + x[alphanum.start():]
	return portage.isvalidatom(x)

def show_blocker_docs_link():
	print
	print "For more information about " + bad("Blocked Packages") + ", please refer to the following"
	print "section of the Gentoo Linux x86 Handbook (architecture is irrelevant):"
	print
	print "http://www.gentoo.org/doc/en/handbook/handbook-x86.xml?full=1#blocked"
	print

def show_mask_docs():
	print "For more information, see the MASKED PACKAGES section in the emerge"
	print "man page or refer to the Gentoo Handbook."

def action_sync(settings, trees, mtimedb, myopts, myaction):
	xterm_titles = "notitles" not in settings.features
	emergelog(xterm_titles, " === sync")
	myportdir = settings.get("PORTDIR", None)
	out = portage.output.EOutput()
	if not myportdir:
		sys.stderr.write("!!! PORTDIR is undefined.  Is /etc/make.globals missing?\n")
		sys.exit(1)
	if myportdir[-1]=="/":
		myportdir=myportdir[:-1]
	try:
		st = os.stat(myportdir)
	except OSError:
		st = None
	if st is None:
		print ">>>",myportdir,"not found, creating it."
		os.makedirs(myportdir,0755)
		st = os.stat(myportdir)

	spawn_kwargs = {}
	spawn_kwargs["env"] = settings.environ()
	if 'usersync' in settings.features and \
		portage.data.secpass >= 2 and \
		(st.st_uid != os.getuid() and st.st_mode & 0700 or \
		st.st_gid != os.getgid() and st.st_mode & 0070):
		try:
			homedir = pwd.getpwuid(st.st_uid).pw_dir
		except KeyError:
			pass
		else:
			# Drop privileges when syncing, in order to match
			# existing uid/gid settings.
			spawn_kwargs["uid"]    = st.st_uid
			spawn_kwargs["gid"]    = st.st_gid
			spawn_kwargs["groups"] = [st.st_gid]
			spawn_kwargs["env"]["HOME"] = homedir
			umask = 0002
			if not st.st_mode & 0020:
				umask = umask | 0020
			spawn_kwargs["umask"] = umask

	syncuri = settings.get("SYNC", "").strip()
	if not syncuri:
		writemsg_level("!!! SYNC is undefined. Is /etc/make.globals missing?\n",
			noiselevel=-1, level=logging.ERROR)
		return 1

	vcs_dirs = frozenset([".git", ".svn", "CVS", ".hg"])
	vcs_dirs = vcs_dirs.intersection(os.listdir(myportdir))

	os.umask(0022)
	dosyncuri = syncuri
	updatecache_flg = False
	if myaction == "metadata":
		print "skipping sync"
		updatecache_flg = True
	elif ".git" in vcs_dirs:
		# Update existing git repository, and ignore the syncuri. We are
		# going to trust the user and assume that the user is in the branch
		# that he/she wants updated. We'll let the user manage branches with
		# git directly.
		if portage.process.find_binary("git") is None:
			msg = ["Command not found: git",
			"Type \"emerge dev-util/git\" to enable git support."]
			for l in msg:
				writemsg_level("!!! %s\n" % l,
					level=logging.ERROR, noiselevel=-1)
			return 1
		msg = ">>> Starting git pull in %s..." % myportdir
		emergelog(xterm_titles, msg )
		writemsg_level(msg + "\n")
		exitcode = portage.process.spawn_bash("cd %s ; git pull" % \
			(portage._shell_quote(myportdir),), **spawn_kwargs)
		if exitcode != os.EX_OK:
			msg = "!!! git pull error in %s." % myportdir
			emergelog(xterm_titles, msg)
			writemsg_level(msg + "\n", level=logging.ERROR, noiselevel=-1)
			return exitcode
		msg = ">>> Git pull in %s successful" % myportdir
		emergelog(xterm_titles, msg)
		writemsg_level(msg + "\n")
		exitcode = git_sync_timestamps(settings, myportdir)
		if exitcode == os.EX_OK:
			updatecache_flg = True
	elif syncuri[:8]=="rsync://":
		for vcs_dir in vcs_dirs:
			writemsg_level(("!!! %s appears to be under revision " + \
				"control (contains %s).\n!!! Aborting rsync sync.\n") % \
				(myportdir, vcs_dir), level=logging.ERROR, noiselevel=-1)
			return 1
		if not os.path.exists("/usr/bin/rsync"):
			print "!!! /usr/bin/rsync does not exist, so rsync support is disabled."
			print "!!! Type \"emerge net-misc/rsync\" to enable rsync support."
			sys.exit(1)
		mytimeout=180

		rsync_opts = []
		if settings["PORTAGE_RSYNC_OPTS"] == "":
			portage.writemsg("PORTAGE_RSYNC_OPTS empty or unset, using hardcoded defaults\n")
			rsync_opts.extend([
				"--recursive",    # Recurse directories
				"--links",        # Consider symlinks
				"--safe-links",   # Ignore links outside of tree
				"--perms",        # Preserve permissions
				"--times",        # Preserive mod times
				"--compress",     # Compress the data transmitted
				"--force",        # Force deletion on non-empty dirs
				"--whole-file",   # Don't do block transfers, only entire files
				"--delete",       # Delete files that aren't in the master tree
				"--stats",        # Show final statistics about what was transfered
				"--timeout="+str(mytimeout), # IO timeout if not done in X seconds
				"--exclude=/distfiles",   # Exclude distfiles from consideration
				"--exclude=/local",       # Exclude local     from consideration
				"--exclude=/packages",    # Exclude packages  from consideration
			])

		else:
			# The below validation is not needed when using the above hardcoded
			# defaults.

			portage.writemsg("Using PORTAGE_RSYNC_OPTS instead of hardcoded defaults\n", 1)
			rsync_opts.extend(
				shlex.split(settings.get("PORTAGE_RSYNC_OPTS","")))
			for opt in ("--recursive", "--times"):
				if opt not in rsync_opts:
					portage.writemsg(yellow("WARNING:") + " adding required option " + \
					"%s not included in PORTAGE_RSYNC_OPTS\n" % opt)
					rsync_opts.append(opt)
	
			for exclude in ("distfiles", "local", "packages"):
				opt = "--exclude=/%s" % exclude
				if opt not in rsync_opts:
					portage.writemsg(yellow("WARNING:") + \
					" adding required option %s not included in "  % opt + \
					"PORTAGE_RSYNC_OPTS (can be overridden with --exclude='!')\n")
					rsync_opts.append(opt)
	
			if syncuri.rstrip("/").endswith(".gentoo.org/gentoo-portage"):
				def rsync_opt_startswith(opt_prefix):
					for x in rsync_opts:
						if x.startswith(opt_prefix):
							return True
					return False

				if not rsync_opt_startswith("--timeout="):
					rsync_opts.append("--timeout=%d" % mytimeout)

				for opt in ("--compress", "--whole-file"):
					if opt not in rsync_opts:
						portage.writemsg(yellow("WARNING:") + " adding required option " + \
						"%s not included in PORTAGE_RSYNC_OPTS\n" % opt)
						rsync_opts.append(opt)

		if "--quiet" in myopts:
			rsync_opts.append("--quiet")    # Shut up a lot
		else:
			rsync_opts.append("--verbose")	# Print filelist

		if "--verbose" in myopts:
			rsync_opts.append("--progress")  # Progress meter for each file

		if "--debug" in myopts:
			rsync_opts.append("--checksum") # Force checksum on all files

		# Real local timestamp file.
		servertimestampfile = os.path.join(
			myportdir, "metadata", "timestamp.chk")

		content = portage.util.grabfile(servertimestampfile)
		mytimestamp = 0
		if content:
			try:
				mytimestamp = time.mktime(time.strptime(content[0],
					"%a, %d %b %Y %H:%M:%S +0000"))
			except (OverflowError, ValueError):
				pass
		del content

		try:
			rsync_initial_timeout = \
				int(settings.get("PORTAGE_RSYNC_INITIAL_TIMEOUT", "15"))
		except ValueError:
			rsync_initial_timeout = 15

		try:
			maxretries=int(settings["PORTAGE_RSYNC_RETRIES"])
		except SystemExit, e:
			raise # Needed else can't exit
		except:
			maxretries=3 #default number of retries

		retries=0
		user_name, hostname, port = re.split(
			"rsync://([^:/]+@)?([^:/]*)(:[0-9]+)?", syncuri, maxsplit=3)[1:4]
		if port is None:
			port=""
		if user_name is None:
			user_name=""
		updatecache_flg=True
		all_rsync_opts = set(rsync_opts)
		extra_rsync_opts = shlex.split(
			settings.get("PORTAGE_RSYNC_EXTRA_OPTS",""))
		all_rsync_opts.update(extra_rsync_opts)
		family = socket.AF_INET
		if "-4" in all_rsync_opts or "--ipv4" in all_rsync_opts:
			family = socket.AF_INET
		elif socket.has_ipv6 and \
			("-6" in all_rsync_opts or "--ipv6" in all_rsync_opts):
			family = socket.AF_INET6
		ips=[]
		SERVER_OUT_OF_DATE = -1
		EXCEEDED_MAX_RETRIES = -2
		while (1):
			if ips:
				del ips[0]
			if ips==[]:
				try:
					for addrinfo in socket.getaddrinfo(
						hostname, None, family, socket.SOCK_STREAM):
						if socket.has_ipv6 and addrinfo[0] == socket.AF_INET6:
							# IPv6 addresses need to be enclosed in square brackets
							ips.append("[%s]" % addrinfo[4][0])
						else:
							ips.append(addrinfo[4][0])
					from random import shuffle
					shuffle(ips)
				except SystemExit, e:
					raise # Needed else can't exit
				except Exception, e:
					print "Notice:",str(e)
					dosyncuri=syncuri

			if ips:
				try:
					dosyncuri = syncuri.replace(
						"//" + user_name + hostname + port + "/",
						"//" + user_name + ips[0] + port + "/", 1)
				except SystemExit, e:
					raise # Needed else can't exit
				except Exception, e:
					print "Notice:",str(e)
					dosyncuri=syncuri

			if (retries==0):
				if "--ask" in myopts:
					if userquery("Do you want to sync your Portage tree with the mirror at\n" + blue(dosyncuri) + bold("?"))=="No":
						print
						print "Quitting."
						print
						sys.exit(0)
				emergelog(xterm_titles, ">>> Starting rsync with " + dosyncuri)
				if "--quiet" not in myopts:
					print ">>> Starting rsync with "+dosyncuri+"..."
			else:
				emergelog(xterm_titles,
					">>> Starting retry %d of %d with %s" % \
						(retries,maxretries,dosyncuri))
				print "\n\n>>> Starting retry %d of %d with %s" % (retries,maxretries,dosyncuri)

			if mytimestamp != 0 and "--quiet" not in myopts:
				print ">>> Checking server timestamp ..."

			rsynccommand = ["/usr/bin/rsync"] + rsync_opts + extra_rsync_opts

			if "--debug" in myopts:
				print rsynccommand

			exitcode = os.EX_OK
			servertimestamp = 0
			# Even if there's no timestamp available locally, fetch the
			# timestamp anyway as an initial probe to verify that the server is
			# responsive.  This protects us from hanging indefinitely on a
			# connection attempt to an unresponsive server which rsync's
			# --timeout option does not prevent.
			if True:
				# Temporary file for remote server timestamp comparison.
				from tempfile import mkstemp
				fd, tmpservertimestampfile = mkstemp()
				os.close(fd)
				mycommand = rsynccommand[:]
				mycommand.append(dosyncuri.rstrip("/") + \
					"/metadata/timestamp.chk")
				mycommand.append(tmpservertimestampfile)
				content = None
				mypids = []
				try:
					def timeout_handler(signum, frame):
						raise portage.exception.PortageException("timed out")
					signal.signal(signal.SIGALRM, timeout_handler)
					# Timeout here in case the server is unresponsive.  The
					# --timeout rsync option doesn't apply to the initial
					# connection attempt.
					if rsync_initial_timeout:
						signal.alarm(rsync_initial_timeout)
					try:
						mypids.extend(portage.process.spawn(
							mycommand, env=settings.environ(), returnpid=True))
						exitcode = os.waitpid(mypids[0], 0)[1]
						content = portage.grabfile(tmpservertimestampfile)
					finally:
						if rsync_initial_timeout:
							signal.alarm(0)
						try:
							os.unlink(tmpservertimestampfile)
						except OSError:
							pass
				except portage.exception.PortageException, e:
					# timed out
					print e
					del e
					if mypids and os.waitpid(mypids[0], os.WNOHANG) == (0,0):
						os.kill(mypids[0], signal.SIGTERM)
						os.waitpid(mypids[0], 0)
					# This is the same code rsync uses for timeout.
					exitcode = 30
				else:
					if exitcode != os.EX_OK:
						if exitcode & 0xff:
							exitcode = (exitcode & 0xff) << 8
						else:
							exitcode = exitcode >> 8
				if mypids:
					portage.process.spawned_pids.remove(mypids[0])
				if content:
					try:
						servertimestamp = time.mktime(time.strptime(
							content[0], "%a, %d %b %Y %H:%M:%S +0000"))
					except (OverflowError, ValueError):
						pass
				del mycommand, mypids, content
			if exitcode == os.EX_OK:
				if (servertimestamp != 0) and (servertimestamp == mytimestamp):
					emergelog(xterm_titles,
						">>> Cancelling sync -- Already current.")
					print
					print ">>>"
					print ">>> Timestamps on the server and in the local repository are the same."
					print ">>> Cancelling all further sync action. You are already up to date."
					print ">>>"
					print ">>> In order to force sync, remove '%s'." % servertimestampfile
					print ">>>"
					print
					sys.exit(0)
				elif (servertimestamp != 0) and (servertimestamp < mytimestamp):
					emergelog(xterm_titles,
						">>> Server out of date: %s" % dosyncuri)
					print
					print ">>>"
					print ">>> SERVER OUT OF DATE: %s" % dosyncuri
					print ">>>"
					print ">>> In order to force sync, remove '%s'." % servertimestampfile
					print ">>>"
					print
					exitcode = SERVER_OUT_OF_DATE
				elif (servertimestamp == 0) or (servertimestamp > mytimestamp):
					# actual sync
					mycommand = rsynccommand + [dosyncuri+"/", myportdir]
					exitcode = portage.process.spawn(mycommand, **spawn_kwargs)
					if exitcode in [0,1,3,4,11,14,20,21]:
						break
			elif exitcode in [1,3,4,11,14,20,21]:
				break
			else:
				# Code 2 indicates protocol incompatibility, which is expected
				# for servers with protocol < 29 that don't support
				# --prune-empty-directories.  Retry for a server that supports
				# at least rsync protocol version 29 (>=rsync-2.6.4).
				pass

			retries=retries+1

			if retries<=maxretries:
				print ">>> Retrying..."
				time.sleep(11)
			else:
				# over retries
				# exit loop
				updatecache_flg=False
				exitcode = EXCEEDED_MAX_RETRIES
				break

		if (exitcode==0):
			emergelog(xterm_titles, "=== Sync completed with %s" % dosyncuri)
		elif exitcode == SERVER_OUT_OF_DATE:
			sys.exit(1)
		elif exitcode == EXCEEDED_MAX_RETRIES:
			sys.stderr.write(
				">>> Exceeded PORTAGE_RSYNC_RETRIES: %s\n" % maxretries)
			sys.exit(1)
		elif (exitcode>0):
			msg = []
			if exitcode==1:
				msg.append("Rsync has reported that there is a syntax error. Please ensure")
				msg.append("that your SYNC statement is proper.")
				msg.append("SYNC=" + settings["SYNC"])
			elif exitcode==11:
				msg.append("Rsync has reported that there is a File IO error. Normally")
				msg.append("this means your disk is full, but can be caused by corruption")
				msg.append("on the filesystem that contains PORTDIR. Please investigate")
				msg.append("and try again after the problem has been fixed.")
				msg.append("PORTDIR=" + settings["PORTDIR"])
			elif exitcode==20:
				msg.append("Rsync was killed before it finished.")
			else:
				msg.append("Rsync has not successfully finished. It is recommended that you keep")
				msg.append("trying or that you use the 'emerge-webrsync' option if you are unable")
				msg.append("to use rsync due to firewall or other restrictions. This should be a")
				msg.append("temporary problem unless complications exist with your network")
				msg.append("(and possibly your system's filesystem) configuration.")
			for line in msg:
				out.eerror(line)
			sys.exit(exitcode)
	elif syncuri[:6]=="cvs://":
		if not os.path.exists("/usr/bin/cvs"):
			print "!!! /usr/bin/cvs does not exist, so CVS support is disabled."
			print "!!! Type \"emerge dev-util/cvs\" to enable CVS support."
			sys.exit(1)
		cvsroot=syncuri[6:]
		cvsdir=os.path.dirname(myportdir)
		if not os.path.exists(myportdir+"/CVS"):
			#initial checkout
			print ">>> Starting initial cvs checkout with "+syncuri+"..."
			if os.path.exists(cvsdir+"/gentoo-x86"):
				print "!!! existing",cvsdir+"/gentoo-x86 directory; exiting."
				sys.exit(1)
			try:
				os.rmdir(myportdir)
			except OSError, e:
				if e.errno != errno.ENOENT:
					sys.stderr.write(
						"!!! existing '%s' directory; exiting.\n" % myportdir)
					sys.exit(1)
				del e
			if portage.spawn("cd "+cvsdir+"; cvs -z0 -d "+cvsroot+" co -P gentoo-x86",settings,free=1):
				print "!!! cvs checkout error; exiting."
				sys.exit(1)
			os.rename(os.path.join(cvsdir, "gentoo-x86"), myportdir)
		else:
			#cvs update
			print ">>> Starting cvs update with "+syncuri+"..."
			retval = portage.process.spawn_bash(
				"cd %s; cvs -z0 -q update -dP" % \
				(portage._shell_quote(myportdir),), **spawn_kwargs)
			if retval != os.EX_OK:
				sys.exit(retval)
		dosyncuri = syncuri
	else:
		writemsg_level("!!! Unrecognized protocol: SYNC='%s'\n" % (syncuri,),
			noiselevel=-1, level=logging.ERROR)
		return 1

	if updatecache_flg and  \
		myaction != "metadata" and \
		"metadata-transfer" not in settings.features:
		updatecache_flg = False

	# Reload the whole config from scratch.
	settings, trees, mtimedb = load_emerge_config(trees=trees)
	root_config = trees[settings["ROOT"]]["root_config"]
	portdb = trees[settings["ROOT"]]["porttree"].dbapi

	if os.path.exists(myportdir+"/metadata/cache") and updatecache_flg:
		action_metadata(settings, portdb, myopts)

	if portage._global_updates(trees, mtimedb["updates"]):
		mtimedb.commit()
		# Reload the whole config from scratch.
		settings, trees, mtimedb = load_emerge_config(trees=trees)
		portdb = trees[settings["ROOT"]]["porttree"].dbapi
		root_config = trees[settings["ROOT"]]["root_config"]

	mybestpv = portdb.xmatch("bestmatch-visible",
		portage.const.PORTAGE_PACKAGE_ATOM)
	mypvs = portage.best(
		trees[settings["ROOT"]]["vartree"].dbapi.match(
		portage.const.PORTAGE_PACKAGE_ATOM))

	chk_updated_cfg_files("/", settings.get("CONFIG_PROTECT","").split())

	if myaction != "metadata":
		if os.access(portage.USER_CONFIG_PATH + "/bin/post_sync", os.X_OK):
			retval = portage.process.spawn(
				[os.path.join(portage.USER_CONFIG_PATH, "bin", "post_sync"),
				dosyncuri], env=settings.environ())
			if retval != os.EX_OK:
				print red(" * ")+bold("spawn failed of "+ portage.USER_CONFIG_PATH + "/bin/post_sync")

	if(mybestpv != mypvs) and not "--quiet" in myopts:
		print
		print red(" * ")+bold("An update to portage is available.")+" It is _highly_ recommended"
		print red(" * ")+"that you update portage now, before any other packages are updated."
		print
		print red(" * ")+"To update portage, run 'emerge portage' now."
		print
	
	display_news_notification(root_config, myopts)
	return os.EX_OK

def git_sync_timestamps(settings, portdir):
	"""
	Since git doesn't preserve timestamps, synchronize timestamps between
	entries and ebuilds/eclasses. Assume the cache has the correct timestamp
	for a given file as long as the file in the working tree is not modified
	(relative to HEAD).
	"""
	cache_dir = os.path.join(portdir, "metadata", "cache")
	if not os.path.isdir(cache_dir):
		return os.EX_OK
	writemsg_level(">>> Synchronizing timestamps...\n")

	from portage.cache.cache_errors import CacheError
	try:
		cache_db = settings.load_best_module("portdbapi.metadbmodule")(
			portdir, "metadata/cache", portage.auxdbkeys[:], readonly=True)
	except CacheError, e:
		writemsg_level("!!! Unable to instantiate cache: %s\n" % (e,),
			level=logging.ERROR, noiselevel=-1)
		return 1

	ec_dir = os.path.join(portdir, "eclass")
	try:
		ec_names = set(f[:-7] for f in os.listdir(ec_dir) \
			if f.endswith(".eclass"))
	except OSError, e:
		writemsg_level("!!! Unable to list eclasses: %s\n" % (e,),
			level=logging.ERROR, noiselevel=-1)
		return 1

	args = [portage.const.BASH_BINARY, "-c",
		"cd %s && git diff-index --name-only --diff-filter=M HEAD" % \
		portage._shell_quote(portdir)]
	import subprocess
	proc = subprocess.Popen(args, stdout=subprocess.PIPE)
	modified_files = set(l.rstrip("\n") for l in proc.stdout)
	rval = proc.wait()
	if rval != os.EX_OK:
		return rval

	modified_eclasses = set(ec for ec in ec_names \
		if os.path.join("eclass", ec + ".eclass") in modified_files)

	updated_ec_mtimes = {}

	for cpv in cache_db:
		cpv_split = portage.catpkgsplit(cpv)
		if cpv_split is None:
			writemsg_level("!!! Invalid cache entry: %s\n" % (cpv,),
				level=logging.ERROR, noiselevel=-1)
			continue

		cat, pn, ver, rev = cpv_split
		cat, pf = portage.catsplit(cpv)
		relative_eb_path = os.path.join(cat, pn, pf + ".ebuild")
		if relative_eb_path in modified_files:
			continue

		try:
			cache_entry = cache_db[cpv]
			eb_mtime = cache_entry.get("_mtime_")
			ec_mtimes = cache_entry.get("_eclasses_")
		except KeyError:
			writemsg_level("!!! Missing cache entry: %s\n" % (cpv,),
				level=logging.ERROR, noiselevel=-1)
			continue
		except CacheError, e:
			writemsg_level("!!! Unable to access cache entry: %s %s\n" % \
				(cpv, e), level=logging.ERROR, noiselevel=-1)
			continue

		if eb_mtime is None:
			writemsg_level("!!! Missing ebuild mtime: %s\n" % (cpv,),
				level=logging.ERROR, noiselevel=-1)
			continue

		try:
			eb_mtime = long(eb_mtime)
		except ValueError:
			writemsg_level("!!! Invalid ebuild mtime: %s %s\n" % \
				(cpv, eb_mtime), level=logging.ERROR, noiselevel=-1)
			continue

		if ec_mtimes is None:
			writemsg_level("!!! Missing eclass mtimes: %s\n" % (cpv,),
				level=logging.ERROR, noiselevel=-1)
			continue

		if modified_eclasses.intersection(ec_mtimes):
			continue

		missing_eclasses = set(ec_mtimes).difference(ec_names)
		if missing_eclasses:
			writemsg_level("!!! Non-existent eclass(es): %s %s\n" % \
				(cpv, sorted(missing_eclasses)), level=logging.ERROR,
				noiselevel=-1)
			continue

		eb_path = os.path.join(portdir, relative_eb_path)
		try:
			current_eb_mtime = os.stat(eb_path)
		except OSError:
			writemsg_level("!!! Missing ebuild: %s\n" % \
				(cpv,), level=logging.ERROR, noiselevel=-1)
			continue

		inconsistent = False
		for ec, (ec_path, ec_mtime) in ec_mtimes.iteritems():
			updated_mtime = updated_ec_mtimes.get(ec)
			if updated_mtime is not None and updated_mtime != ec_mtime:
				writemsg_level("!!! Inconsistent eclass mtime: %s %s\n" % \
					(cpv, ec), level=logging.ERROR, noiselevel=-1)
				inconsistent = True
				break

		if inconsistent:
			continue

		if current_eb_mtime != eb_mtime:
			os.utime(eb_path, (eb_mtime, eb_mtime))

		for ec, (ec_path, ec_mtime) in ec_mtimes.iteritems():
			if ec in updated_ec_mtimes:
				continue
			ec_path = os.path.join(ec_dir, ec + ".eclass")
			current_mtime = long(os.stat(ec_path).st_mtime)
			if current_mtime != ec_mtime:
				os.utime(ec_path, (ec_mtime, ec_mtime))
			updated_ec_mtimes[ec] = ec_mtime

	return os.EX_OK

def action_metadata(settings, portdb, myopts):
	portage.writemsg_stdout("\n>>> Updating Portage cache:      ")
	old_umask = os.umask(0002)
	cachedir = os.path.normpath(settings.depcachedir)
	if cachedir in ["/",    "/bin", "/dev",  "/etc",  "/home",
					"/lib", "/opt", "/proc", "/root", "/sbin",
					"/sys", "/tmp", "/usr",  "/var"]:
		print >> sys.stderr, "!!! PORTAGE_DEPCACHEDIR IS SET TO A PRIMARY " + \
			"ROOT DIRECTORY ON YOUR SYSTEM."
		print >> sys.stderr, \
			"!!! This is ALMOST CERTAINLY NOT what you want: '%s'" % cachedir
		sys.exit(73)
	if not os.path.exists(cachedir):
		os.mkdir(cachedir)

	ec = portage.eclass_cache.cache(portdb.porttree_root)
	myportdir = os.path.realpath(settings["PORTDIR"])
	cm = settings.load_best_module("portdbapi.metadbmodule")(
		myportdir, "metadata/cache", portage.auxdbkeys[:], readonly=True)

	from portage.cache import util

	class percentage_noise_maker(util.quiet_mirroring):
		def __init__(self, dbapi):
			self.dbapi = dbapi
			self.cp_all = dbapi.cp_all()
			l = len(self.cp_all)
			self.call_update_min = 100000000
			self.min_cp_all = l/100.0
			self.count = 1
			self.pstr = ''

		def __iter__(self):
			for x in self.cp_all:
				self.count += 1
				if self.count > self.min_cp_all:
					self.call_update_min = 0
					self.count = 0
				for y in self.dbapi.cp_list(x):
					yield y
			self.call_update_mine = 0

		def update(self, *arg):
			try:				self.pstr = int(self.pstr) + 1
			except ValueError:	self.pstr = 1
			sys.stdout.write("%s%i%%" % \
				("\b" * (len(str(self.pstr))+1), self.pstr))
			sys.stdout.flush()
			self.call_update_min = 10000000

		def finish(self, *arg):
			sys.stdout.write("\b\b\b\b100%\n")
			sys.stdout.flush()

	if "--quiet" in myopts:
		def quicky_cpv_generator(cp_all_list):
			for x in cp_all_list:
				for y in portdb.cp_list(x):
					yield y
		source = quicky_cpv_generator(portdb.cp_all())
		noise_maker = portage.cache.util.quiet_mirroring()
	else:
		noise_maker = source = percentage_noise_maker(portdb)
	portage.cache.util.mirror_cache(source, cm, portdb.auxdb[myportdir],
		eclass_cache=ec, verbose_instance=noise_maker)

	sys.stdout.flush()
	os.umask(old_umask)

def action_regen(settings, portdb, max_jobs, max_load):
	xterm_titles = "notitles" not in settings.features
	emergelog(xterm_titles, " === regen")
	#regenerate cache entries
	portage.writemsg_stdout("Regenerating cache entries...\n")
	try:
		os.close(sys.stdin.fileno())
	except SystemExit, e:
		raise # Needed else can't exit
	except:
		pass
	sys.stdout.flush()

	regen = MetadataRegen(portdb, max_jobs=max_jobs, max_load=max_load)
	regen.run()

	portage.writemsg_stdout("done!\n")
	return regen.returncode

def action_config(settings, trees, myopts, myfiles):
	if len(myfiles) != 1:
		print red("!!! config can only take a single package atom at this time\n")
		sys.exit(1)
	if not is_valid_package_atom(myfiles[0]):
		portage.writemsg("!!! '%s' is not a valid package atom.\n" % myfiles[0],
			noiselevel=-1)
		portage.writemsg("!!! Please check ebuild(5) for full details.\n")
		portage.writemsg("!!! (Did you specify a version but forget to prefix with '='?)\n")
		sys.exit(1)
	print
	try:
		pkgs = trees[settings["ROOT"]]["vartree"].dbapi.match(myfiles[0])
	except portage.exception.AmbiguousPackageName, e:
		# Multiple matches thrown from cpv_expand
		pkgs = e.args[0]
	if len(pkgs) == 0:
		print "No packages found.\n"
		sys.exit(0)
	elif len(pkgs) > 1:
		if "--ask" in myopts:
			options = []
			print "Please select a package to configure:"
			idx = 0
			for pkg in pkgs:
				idx += 1
				options.append(str(idx))
				print options[-1]+") "+pkg
			print "X) Cancel"
			options.append("X")
			idx = userquery("Selection?", options)
			if idx == "X":
				sys.exit(0)
			pkg = pkgs[int(idx)-1]
		else:
			print "The following packages available:"
			for pkg in pkgs:
				print "* "+pkg
			print "\nPlease use a specific atom or the --ask option."
			sys.exit(1)
	else:
		pkg = pkgs[0]

	print
	if "--ask" in myopts:
		if userquery("Ready to configure "+pkg+"?") == "No":
			sys.exit(0)
	else:
		print "Configuring pkg..."
	print
	ebuildpath = trees[settings["ROOT"]]["vartree"].dbapi.findname(pkg)
	mysettings = portage.config(clone=settings)
	vardb = trees[mysettings["ROOT"]]["vartree"].dbapi
	debug = mysettings.get("PORTAGE_DEBUG") == "1"
	retval = portage.doebuild(ebuildpath, "config", mysettings["ROOT"],
		mysettings,
		debug=(settings.get("PORTAGE_DEBUG", "") == 1), cleanup=True,
		mydbapi=trees[settings["ROOT"]]["vartree"].dbapi, tree="vartree")
	if retval == os.EX_OK:
		portage.doebuild(ebuildpath, "clean", mysettings["ROOT"],
			mysettings, debug=debug, mydbapi=vardb, tree="vartree")
	print

def action_info(settings, trees, myopts, myfiles):
	print getportageversion(settings["PORTDIR"], settings["ROOT"],
		settings.profile_path, settings["CHOST"],
		trees[settings["ROOT"]]["vartree"].dbapi)
	header_width = 65
	header_title = "System Settings"
	if myfiles:
		print header_width * "="
		print header_title.rjust(int(header_width/2 + len(header_title)/2))
	print header_width * "="
	print "System uname: "+platform.platform(aliased=1)

	lastSync = portage.grabfile(os.path.join(
		settings["PORTDIR"], "metadata", "timestamp.chk"))
	print "Timestamp of tree:",
	if lastSync:
		print lastSync[0]
	else:
		print "Unknown"

	output=commands.getstatusoutput("distcc --version")
	if not output[0]:
		print str(output[1].split("\n",1)[0]),
		if "distcc" in settings.features:
			print "[enabled]"
		else:
			print "[disabled]"

	output=commands.getstatusoutput("ccache -V")
	if not output[0]:
		print str(output[1].split("\n",1)[0]),
		if "ccache" in settings.features:
			print "[enabled]"
		else:
			print "[disabled]"

	myvars  = ["sys-devel/autoconf", "sys-devel/automake", "virtual/os-headers",
	           "sys-devel/binutils", "sys-devel/libtool",  "dev-lang/python"]
	myvars += portage.util.grabfile(settings["PORTDIR"]+"/profiles/info_pkgs")
	myvars  = portage.util.unique_array(myvars)
	myvars.sort()

	for x in myvars:
		if portage.isvalidatom(x):
			pkg_matches = trees["/"]["vartree"].dbapi.match(x)
			pkg_matches = [portage.catpkgsplit(cpv)[1:] for cpv in pkg_matches]
			pkg_matches.sort(key=cmp_sort_key(portage.pkgcmp))
			pkgs = []
			for pn, ver, rev in pkg_matches:
				if rev != "r0":
					pkgs.append(ver + "-" + rev)
				else:
					pkgs.append(ver)
			if pkgs:
				pkgs = ", ".join(pkgs)
				print "%-20s %s" % (x+":", pkgs)
		else:
			print "%-20s %s" % (x+":", "[NOT VALID]")

	libtool_vers = ",".join(trees["/"]["vartree"].dbapi.match("sys-devel/libtool"))

	if "--verbose" in myopts:
		myvars=settings.keys()
	else:
		myvars = ['GENTOO_MIRRORS', 'CONFIG_PROTECT', 'CONFIG_PROTECT_MASK',
		          'PORTDIR', 'DISTDIR', 'PKGDIR', 'PORTAGE_TMPDIR',
		          'PORTDIR_OVERLAY', 'USE', 'CHOST', 'CFLAGS', 'CXXFLAGS',
		          'ACCEPT_KEYWORDS', 'SYNC', 'FEATURES', 'EMERGE_DEFAULT_OPTS']

		myvars.extend(portage.util.grabfile(settings["PORTDIR"]+"/profiles/info_vars"))

	myvars = portage.util.unique_array(myvars)
	unset_vars = []
	myvars.sort()
	for x in myvars:
		if x in settings:
			if x != "USE":
				print '%s="%s"' % (x, settings[x])
			else:
				use = set(settings["USE"].split())
				use_expand = settings["USE_EXPAND"].split()
				use_expand.sort()
				for varname in use_expand:
					flag_prefix = varname.lower() + "_"
					for f in list(use):
						if f.startswith(flag_prefix):
							use.remove(f)
				use = list(use)
				use.sort()
				print 'USE="%s"' % " ".join(use),
				for varname in use_expand:
					myval = settings.get(varname)
					if myval:
						print '%s="%s"' % (varname, myval),
				print
		else:
			unset_vars.append(x)
	if unset_vars:
		print "Unset:  "+", ".join(unset_vars)
	print

	if "--debug" in myopts:
		for x in dir(portage):
			module = getattr(portage, x)
			if "cvs_id_string" in dir(module):
				print "%s: %s" % (str(x), str(module.cvs_id_string))

	# See if we can find any packages installed matching the strings
	# passed on the command line
	mypkgs = []
	vardb = trees[settings["ROOT"]]["vartree"].dbapi
	portdb = trees[settings["ROOT"]]["porttree"].dbapi
	for x in myfiles:
		mypkgs.extend(vardb.match(x))

	# If some packages were found...
	if mypkgs:
		# Get our global settings (we only print stuff if it varies from
		# the current config)
		mydesiredvars = [ 'CHOST', 'CFLAGS', 'CXXFLAGS', 'LDFLAGS' ]
		auxkeys = mydesiredvars + [ "USE", "IUSE"]
		global_vals = {}
		pkgsettings = portage.config(clone=settings)

		for myvar in mydesiredvars:
			global_vals[myvar] = set(settings.get(myvar, "").split())

		# Loop through each package
		# Only print settings if they differ from global settings
		header_title = "Package Settings"
		print header_width * "="
		print header_title.rjust(int(header_width/2 + len(header_title)/2))
		print header_width * "="
		from portage.output import EOutput
		out = EOutput()
		for pkg in mypkgs:
			# Get all package specific variables
			auxvalues = vardb.aux_get(pkg, auxkeys)
			valuesmap = {}
			for i in xrange(len(auxkeys)):
				valuesmap[auxkeys[i]] = set(auxvalues[i].split())
			diff_values = {}
			for myvar in mydesiredvars:
				# If the package variable doesn't match the
				# current global variable, something has changed
				# so set diff_found so we know to print
				if valuesmap[myvar] != global_vals[myvar]:
					diff_values[myvar] = valuesmap[myvar]
			valuesmap["IUSE"] = set(filter_iuse_defaults(valuesmap["IUSE"]))
			valuesmap["USE"] = valuesmap["USE"].intersection(valuesmap["IUSE"])
			pkgsettings.reset()
			# If a matching ebuild is no longer available in the tree, maybe it
			# would make sense to compare against the flags for the best
			# available version with the same slot?
			mydb = None
			if portdb.cpv_exists(pkg):
				mydb = portdb
			pkgsettings.setcpv(pkg, mydb=mydb)
			if valuesmap["IUSE"].intersection(
				pkgsettings["PORTAGE_USE"].split()) != valuesmap["USE"]:
				diff_values["USE"] = valuesmap["USE"]
			# If a difference was found, print the info for
			# this package.
			if diff_values:
				# Print package info
				print "%s was built with the following:" % pkg
				for myvar in mydesiredvars + ["USE"]:
					if myvar in diff_values:
						mylist = list(diff_values[myvar])
						mylist.sort()
						print "%s=\"%s\"" % (myvar, " ".join(mylist))
				print
			print ">>> Attempting to run pkg_info() for '%s'" % pkg
			ebuildpath = vardb.findname(pkg)
			if not ebuildpath or not os.path.exists(ebuildpath):
				out.ewarn("No ebuild found for '%s'" % pkg)
				continue
			portage.doebuild(ebuildpath, "info", pkgsettings["ROOT"],
				pkgsettings, debug=(settings.get("PORTAGE_DEBUG", "") == 1),
				mydbapi=trees[settings["ROOT"]]["vartree"].dbapi,
				tree="vartree")

def action_search(root_config, myopts, myfiles, spinner):
	if not myfiles:
		print "emerge: no search terms provided."
	else:
		searchinstance = search(root_config,
			spinner, "--searchdesc" in myopts,
			"--quiet" not in myopts, "--usepkg" in myopts,
			"--usepkgonly" in myopts)
		for mysearch in myfiles:
			try:
				searchinstance.execute(mysearch)
			except re.error, comment:
				print "\n!!! Regular expression error in \"%s\": %s" % ( mysearch, comment )
				sys.exit(1)
			searchinstance.output()

def action_depclean(settings, trees, ldpath_mtimes,
	myopts, action, myfiles, spinner):
	# Kill packages that aren't explicitly merged or are required as a
	# dependency of another package. World file is explicit.

	# Global depclean or prune operations are not very safe when there are
	# missing dependencies since it's unknown how badly incomplete
	# the dependency graph is, and we might accidentally remove packages
	# that should have been pulled into the graph. On the other hand, it's
	# relatively safe to ignore missing deps when only asked to remove
	# specific packages.
	allow_missing_deps = len(myfiles) > 0

	msg = []
	msg.append("Always study the list of packages to be cleaned for any obvious\n")
	msg.append("mistakes. Packages that are part of the world set will always\n")
	msg.append("be kept.  They can be manually added to this set with\n")
	msg.append(good("`emerge --noreplace <atom>`") + ".  Packages that are listed in\n")
	msg.append("package.provided (see portage(5)) will be removed by\n")
	msg.append("depclean, even if they are part of the world set.\n")
	msg.append("\n")
	msg.append("As a safety measure, depclean will not remove any packages\n")
	msg.append("unless *all* required dependencies have been resolved.  As a\n")
	msg.append("consequence, it is often necessary to run %s\n" % \
		good("`emerge --update"))
	msg.append(good("--newuse --deep @system @world`") + \
		" prior to depclean.\n")

	if action == "depclean" and "--quiet" not in myopts and not myfiles:
		portage.writemsg_stdout("\n")
		for x in msg:
			portage.writemsg_stdout(colorize("WARN", " * ") + x)

	xterm_titles = "notitles" not in settings.features
	myroot = settings["ROOT"]
	root_config = trees[myroot]["root_config"]
	getSetAtoms = root_config.setconfig.getSetAtoms
	vardb = trees[myroot]["vartree"].dbapi

	required_set_names = ("system", "world")
	required_sets = {}
	set_args = []

	for s in required_set_names:
		required_sets[s] = InternalPackageSet(
			initial_atoms=getSetAtoms(s))

	
	# When removing packages, use a temporary version of world
	# which excludes packages that are intended to be eligible for
	# removal.
	world_temp_set = required_sets["world"]
	system_set = required_sets["system"]

	if not system_set or not world_temp_set:

		if not system_set:
			writemsg_level("!!! You have no system list.\n",
				level=logging.ERROR, noiselevel=-1)

		if not world_temp_set:
			writemsg_level("!!! You have no world file.\n",
					level=logging.WARNING, noiselevel=-1)

		writemsg_level("!!! Proceeding is likely to " + \
			"break your installation.\n",
			level=logging.WARNING, noiselevel=-1)
		if "--pretend" not in myopts:
			countdown(int(settings["EMERGE_WARNING_DELAY"]), ">>> Depclean")

	if action == "depclean":
		emergelog(xterm_titles, " >>> depclean")

	import textwrap
	args_set = InternalPackageSet()
	if myfiles:
		for x in myfiles:
			if not is_valid_package_atom(x):
				writemsg_level("!!! '%s' is not a valid package atom.\n" % x,
					level=logging.ERROR, noiselevel=-1)
				writemsg_level("!!! Please check ebuild(5) for full details.\n")
				return
			try:
				atom = portage.dep_expand(x, mydb=vardb, settings=settings)
			except portage.exception.AmbiguousPackageName, e:
				msg = "The short ebuild name \"" + x + \
					"\" is ambiguous.  Please specify " + \
					"one of the following " + \
					"fully-qualified ebuild names instead:"
				for line in textwrap.wrap(msg, 70):
					writemsg_level("!!! %s\n" % (line,),
						level=logging.ERROR, noiselevel=-1)
				for i in e[0]:
					writemsg_level("    %s\n" % colorize("INFORM", i),
						level=logging.ERROR, noiselevel=-1)
				writemsg_level("\n", level=logging.ERROR, noiselevel=-1)
				return
			args_set.add(atom)
		matched_packages = False
		for x in args_set:
			if vardb.match(x):
				matched_packages = True
				break
		if not matched_packages:
			writemsg_level(">>> No packages selected for removal by %s\n" % \
				action)
			return

	writemsg_level("\nCalculating dependencies  ")
	resolver_params = create_depgraph_params(myopts, "remove")
	resolver = depgraph(settings, trees, myopts, resolver_params, spinner)
	vardb = resolver.trees[myroot]["vartree"].dbapi

	if action == "depclean":

		if args_set:
			# Pull in everything that's installed but not matched
			# by an argument atom since we don't want to clean any
			# package if something depends on it.

			world_temp_set.clear()
			for pkg in vardb:
				spinner.update()

				try:
					if args_set.findAtomForPackage(pkg) is None:
						world_temp_set.add("=" + pkg.cpv)
						continue
				except portage.exception.InvalidDependString, e:
					show_invalid_depstring_notice(pkg,
						pkg.metadata["PROVIDE"], str(e))
					del e
					world_temp_set.add("=" + pkg.cpv)
					continue

	elif action == "prune":

		# Pull in everything that's installed since we don't
		# to prune a package if something depends on it.
		world_temp_set.clear()
		world_temp_set.update(vardb.cp_all())

		if not args_set:

			# Try to prune everything that's slotted.
			for cp in vardb.cp_all():
				if len(vardb.cp_list(cp)) > 1:
					args_set.add(cp)

		# Remove atoms from world that match installed packages
		# that are also matched by argument atoms, but do not remove
		# them if they match the highest installed version.
		for pkg in vardb:
			spinner.update()
			pkgs_for_cp = vardb.match_pkgs(pkg.cp)
			if not pkgs_for_cp or pkg not in pkgs_for_cp:
				raise AssertionError("package expected in matches: " + \
					"cp = %s, cpv = %s matches = %s" % \
					(pkg.cp, pkg.cpv, [str(x) for x in pkgs_for_cp]))

			highest_version = pkgs_for_cp[-1]
			if pkg == highest_version:
				# pkg is the highest version
				world_temp_set.add("=" + pkg.cpv)
				continue

			if len(pkgs_for_cp) <= 1:
				raise AssertionError("more packages expected: " + \
					"cp = %s, cpv = %s matches = %s" % \
					(pkg.cp, pkg.cpv, [str(x) for x in pkgs_for_cp]))

			try:
				if args_set.findAtomForPackage(pkg) is None:
					world_temp_set.add("=" + pkg.cpv)
					continue
			except portage.exception.InvalidDependString, e:
				show_invalid_depstring_notice(pkg,
					pkg.metadata["PROVIDE"], str(e))
				del e
				world_temp_set.add("=" + pkg.cpv)
				continue

	set_args = {}
	for s, package_set in required_sets.iteritems():
		set_atom = SETPREFIX + s
		set_arg = SetArg(arg=set_atom, set=package_set,
			root_config=resolver.roots[myroot])
		set_args[s] = set_arg
		for atom in set_arg.set:
			resolver._dep_stack.append(
				Dependency(atom=atom, root=myroot, parent=set_arg))
			resolver.digraph.add(set_arg, None)

	success = resolver._complete_graph()
	writemsg_level("\b\b... done!\n")

	resolver.display_problems()

	if not success:
		return 1

	def unresolved_deps():

		unresolvable = set()
		for dep in resolver._initially_unsatisfied_deps:
			if isinstance(dep.parent, Package) and \
				(dep.priority > UnmergeDepPriority.SOFT):
				unresolvable.add((dep.atom, dep.parent.cpv))

		if not unresolvable:
			return False

		if unresolvable and not allow_missing_deps:
			prefix = bad(" * ")
			msg = []
			msg.append("Dependencies could not be completely resolved due to")
			msg.append("the following required packages not being installed:")
			msg.append("")
			for atom, parent in unresolvable:
				msg.append("  %s pulled in by:" % (atom,))
				msg.append("    %s" % (parent,))
				msg.append("")
			msg.append("Have you forgotten to run " + \
				good("`emerge --update --newuse --deep @system @world`") + " prior")
			msg.append(("to %s? It may be necessary to manually " + \
				"uninstall packages that no longer") % action)
			msg.append("exist in the portage tree since " + \
				"it may not be possible to satisfy their")
			msg.append("dependencies.  Also, be aware of " + \
				"the --with-bdeps option that is documented")
			msg.append("in " + good("`man emerge`") + ".")
			if action == "prune":
				msg.append("")
				msg.append("If you would like to ignore " + \
					"dependencies then use %s." % good("--nodeps"))
			writemsg_level("".join("%s%s\n" % (prefix, line) for line in msg),
				level=logging.ERROR, noiselevel=-1)
			return True
		return False

	if unresolved_deps():
		return 1

	graph = resolver.digraph.copy()
	required_pkgs_total = 0
	for node in graph:
		if isinstance(node, Package):
			required_pkgs_total += 1

	def show_parents(child_node):
		parent_nodes = graph.parent_nodes(child_node)
		if not parent_nodes:
			# With --prune, the highest version can be pulled in without any
			# real parent since all installed packages are pulled in.  In that
			# case there's nothing to show here.
			return
		parent_strs = []
		for node in parent_nodes:
			parent_strs.append(str(getattr(node, "cpv", node)))
		parent_strs.sort()
		msg = []
		msg.append("  %s pulled in by:\n" % (child_node.cpv,))
		for parent_str in parent_strs:
			msg.append("    %s\n" % (parent_str,))
		msg.append("\n")
		portage.writemsg_stdout("".join(msg), noiselevel=-1)

	def cmp_pkg_cpv(pkg1, pkg2):
		"""Sort Package instances by cpv."""
		if pkg1.cpv > pkg2.cpv:
			return 1
		elif pkg1.cpv == pkg2.cpv:
			return 0
		else:
			return -1

	def create_cleanlist():
		pkgs_to_remove = []

		if action == "depclean":
			if args_set:

				for pkg in sorted(vardb, key=cmp_sort_key(cmp_pkg_cpv)):
					arg_atom = None
					try:
						arg_atom = args_set.findAtomForPackage(pkg)
					except portage.exception.InvalidDependString:
						# this error has already been displayed by now
						continue

					if arg_atom:
						if pkg not in graph:
							pkgs_to_remove.append(pkg)
						elif "--verbose" in myopts:
							show_parents(pkg)

			else:
				for pkg in sorted(vardb, key=cmp_sort_key(cmp_pkg_cpv)):
					if pkg not in graph:
						pkgs_to_remove.append(pkg)
					elif "--verbose" in myopts:
						show_parents(pkg)

		elif action == "prune":
			# Prune really uses all installed instead of world. It's not
			# a real reverse dependency so don't display it as such.
			graph.remove(set_args["world"])

			for atom in args_set:
				for pkg in vardb.match_pkgs(atom):
					if pkg not in graph:
						pkgs_to_remove.append(pkg)
					elif "--verbose" in myopts:
						show_parents(pkg)

		if not pkgs_to_remove:
			writemsg_level(
				">>> No packages selected for removal by %s\n" % action)
			if "--verbose" not in myopts:
				writemsg_level(
					">>> To see reverse dependencies, use %s\n" % \
						good("--verbose"))
			if action == "prune":
				writemsg_level(
					">>> To ignore dependencies, use %s\n" % \
						good("--nodeps"))

		return pkgs_to_remove

	cleanlist = create_cleanlist()

	if len(cleanlist):
		clean_set = set(cleanlist)

		# Check if any of these package are the sole providers of libraries
		# with consumers that have not been selected for removal. If so, these
		# packages and any dependencies need to be added to the graph.
		real_vardb = trees[myroot]["vartree"].dbapi
		linkmap = real_vardb.linkmap
		liblist = linkmap.listLibraryObjects()
		consumer_cache = {}
		provider_cache = {}
		soname_cache = {}
		consumer_map = {}

		writemsg_level(">>> Checking for lib consumers...\n")

		for pkg in cleanlist:
			pkg_dblink = real_vardb._dblink(pkg.cpv)
			provided_libs = set()

			for lib in liblist:
				if pkg_dblink.isowner(lib, myroot):
					provided_libs.add(lib)

			if not provided_libs:
				continue

			consumers = {}
			for lib in provided_libs:
				lib_consumers = consumer_cache.get(lib)
				if lib_consumers is None:
					lib_consumers = linkmap.findConsumers(lib)
					consumer_cache[lib] = lib_consumers
				if lib_consumers:
					consumers[lib] = lib_consumers

			if not consumers:
				continue

			for lib, lib_consumers in consumers.items():
				for consumer_file in list(lib_consumers):
					if pkg_dblink.isowner(consumer_file, myroot):
						lib_consumers.remove(consumer_file)
				if not lib_consumers:
					del consumers[lib]

			if not consumers:
				continue

			for lib, lib_consumers in consumers.iteritems():

				soname = soname_cache.get(lib)
				if soname is None:
					soname = linkmap.getSoname(lib)
					soname_cache[lib] = soname

				consumer_providers = []
				for lib_consumer in lib_consumers:
					providers = provider_cache.get(lib)
					if providers is None:
						providers = linkmap.findProviders(lib_consumer)
						provider_cache[lib_consumer] = providers
					if soname not in providers:
						# Why does this happen?
						continue
					consumer_providers.append(
						(lib_consumer, providers[soname]))

				consumers[lib] = consumer_providers

			consumer_map[pkg] = consumers

		if consumer_map:

			search_files = set()
			for consumers in consumer_map.itervalues():
				for lib, consumer_providers in consumers.iteritems():
					for lib_consumer, providers in consumer_providers:
						search_files.add(lib_consumer)
						search_files.update(providers)

			writemsg_level(">>> Assigning files to packages...\n")
			file_owners = real_vardb._owners.getFileOwnerMap(search_files)

			for pkg, consumers in consumer_map.items():
				for lib, consumer_providers in consumers.items():
					lib_consumers = set()

					for lib_consumer, providers in consumer_providers:
						owner_set = file_owners.get(lib_consumer)
						provider_dblinks = set()
						provider_pkgs = set()

						if len(providers) > 1:
							for provider in providers:
								provider_set = file_owners.get(provider)
								if provider_set is not None:
									provider_dblinks.update(provider_set)

						if len(provider_dblinks) > 1:
							for provider_dblink in provider_dblinks:
								pkg_key = ("installed", myroot,
									provider_dblink.mycpv, "nomerge")
								if pkg_key not in clean_set:
									provider_pkgs.add(vardb.get(pkg_key))

						if provider_pkgs:
							continue

						if owner_set is not None:
							lib_consumers.update(owner_set)

					for consumer_dblink in list(lib_consumers):
						if ("installed", myroot, consumer_dblink.mycpv,
							"nomerge") in clean_set:
							lib_consumers.remove(consumer_dblink)
							continue

					if lib_consumers:
						consumers[lib] = lib_consumers
					else:
						del consumers[lib]
				if not consumers:
					del consumer_map[pkg]

		if consumer_map:
			# TODO: Implement a package set for rebuilding consumer packages.

			msg = "In order to avoid breakage of link level " + \
				"dependencies, one or more packages will not be removed. " + \
				"This can be solved by rebuilding " + \
				"the packages that pulled them in."

			prefix = bad(" * ")
			from textwrap import wrap
			writemsg_level("".join(prefix + "%s\n" % line for \
				line in wrap(msg, 70)), level=logging.WARNING, noiselevel=-1)

			msg = []
			for pkg, consumers in consumer_map.iteritems():
				unique_consumers = set(chain(*consumers.values()))
				unique_consumers = sorted(consumer.mycpv \
					for consumer in unique_consumers)
				msg.append("")
				msg.append("  %s pulled in by:" % (pkg.cpv,))
				for consumer in unique_consumers:
					msg.append("    %s" % (consumer,))
			msg.append("")
			writemsg_level("".join(prefix + "%s\n" % line for line in msg),
				level=logging.WARNING, noiselevel=-1)

			# Add lib providers to the graph as children of lib consumers,
			# and also add any dependencies pulled in by the provider.
			writemsg_level(">>> Adding lib providers to graph...\n")

			for pkg, consumers in consumer_map.iteritems():
				for consumer_dblink in set(chain(*consumers.values())):
					consumer_pkg = vardb.get(("installed", myroot,
						consumer_dblink.mycpv, "nomerge"))
					if not resolver._add_pkg(pkg,
						Dependency(parent=consumer_pkg,
						priority=UnmergeDepPriority(runtime=True),
						root=pkg.root)):
						resolver.display_problems()
						return 1

			writemsg_level("\nCalculating dependencies  ")
			success = resolver._complete_graph()
			writemsg_level("\b\b... done!\n")
			resolver.display_problems()
			if not success:
				return 1
			if unresolved_deps():
				return 1

			graph = resolver.digraph.copy()
			required_pkgs_total = 0
			for node in graph:
				if isinstance(node, Package):
					required_pkgs_total += 1
			cleanlist = create_cleanlist()
			if not cleanlist:
				return 0
			clean_set = set(cleanlist)

		# Use a topological sort to create an unmerge order such that
		# each package is unmerged before it's dependencies. This is
		# necessary to avoid breaking things that may need to run
		# during pkg_prerm or pkg_postrm phases.

		# Create a new graph to account for dependencies between the
		# packages being unmerged.
		graph = digraph()
		del cleanlist[:]

		dep_keys = ["DEPEND", "RDEPEND", "PDEPEND"]
		runtime = UnmergeDepPriority(runtime=True)
		runtime_post = UnmergeDepPriority(runtime_post=True)
		buildtime = UnmergeDepPriority(buildtime=True)
		priority_map = {
			"RDEPEND": runtime,
			"PDEPEND": runtime_post,
			"DEPEND": buildtime,
		}

		for node in clean_set:
			graph.add(node, None)
			mydeps = []
			node_use = node.metadata["USE"].split()
			for dep_type in dep_keys:
				depstr = node.metadata[dep_type]
				if not depstr:
					continue
				try:
					portage.dep._dep_check_strict = False
					success, atoms = portage.dep_check(depstr, None, settings,
						myuse=node_use, trees=resolver._graph_trees,
						myroot=myroot)
				finally:
					portage.dep._dep_check_strict = True
				if not success:
					# Ignore invalid deps of packages that will
					# be uninstalled anyway.
					continue

				priority = priority_map[dep_type]
				for atom in atoms:
					if not isinstance(atom, portage.dep.Atom):
						# Ignore invalid atoms returned from dep_check().
						continue
					if atom.blocker:
						continue
					matches = vardb.match_pkgs(atom)
					if not matches:
						continue
					for child_node in matches:
						if child_node in clean_set:
							graph.add(child_node, node, priority=priority)

		ordered = True
		if len(graph.order) == len(graph.root_nodes()):
			# If there are no dependencies between packages
			# let unmerge() group them by cat/pn.
			ordered = False
			cleanlist = [pkg.cpv for pkg in graph.order]
		else:
			# Order nodes from lowest to highest overall reference count for
			# optimal root node selection.
			node_refcounts = {}
			for node in graph.order:
				node_refcounts[node] = len(graph.parent_nodes(node))
			def cmp_reference_count(node1, node2):
				return node_refcounts[node1] - node_refcounts[node2]
			graph.order.sort(key=cmp_sort_key(cmp_reference_count))
	
			ignore_priority_range = [None]
			ignore_priority_range.extend(
				xrange(UnmergeDepPriority.MIN, UnmergeDepPriority.MAX + 1))
			while not graph.empty():
				for ignore_priority in ignore_priority_range:
					nodes = graph.root_nodes(ignore_priority=ignore_priority)
					if nodes:
						break
				if not nodes:
					raise AssertionError("no root nodes")
				if ignore_priority is not None:
					# Some deps have been dropped due to circular dependencies,
					# so only pop one node in order do minimize the number that
					# are dropped.
					del nodes[1:]
				for node in nodes:
					graph.remove(node)
					cleanlist.append(node.cpv)

		unmerge(root_config, myopts, "unmerge", cleanlist,
			ldpath_mtimes, ordered=ordered)

	if action == "prune":
		return

	if not cleanlist and "--quiet" in myopts:
		return

	print "Packages installed:   "+str(len(vardb.cpv_all()))
	print "Packages in world:    " + \
		str(len(root_config.sets["world"].getAtoms()))
	print "Packages in system:   " + \
		str(len(root_config.sets["system"].getAtoms()))
	print "Required packages:    "+str(required_pkgs_total)
	if "--pretend" in myopts:
		print "Number to remove:     "+str(len(cleanlist))
	else:
		print "Number removed:       "+str(len(cleanlist))

def resume_depgraph(settings, trees, mtimedb, myopts, myparams, spinner):
	"""
	Construct a depgraph for the given resume list. This will raise
	PackageNotFound or depgraph.UnsatisfiedResumeDep when necessary.
	@rtype: tuple
	@returns: (success, depgraph, dropped_tasks)
	"""
	skip_masked = True
	skip_unsatisfied = True
	mergelist = mtimedb["resume"]["mergelist"]
	dropped_tasks = set()
	while True:
		mydepgraph = depgraph(settings, trees,
			myopts, myparams, spinner)
		try:
			success = mydepgraph.loadResumeCommand(mtimedb["resume"],
				skip_masked=skip_masked)
		except depgraph.UnsatisfiedResumeDep, e:
			if not skip_unsatisfied:
				raise

			graph = mydepgraph.digraph
			unsatisfied_parents = dict((dep.parent, dep.parent) \
				for dep in e.value)
			traversed_nodes = set()
			unsatisfied_stack = list(unsatisfied_parents)
			while unsatisfied_stack:
				pkg = unsatisfied_stack.pop()
				if pkg in traversed_nodes:
					continue
				traversed_nodes.add(pkg)

				# If this package was pulled in by a parent
				# package scheduled for merge, removing this
				# package may cause the the parent package's
				# dependency to become unsatisfied.
				for parent_node in graph.parent_nodes(pkg):
					if not isinstance(parent_node, Package) \
						or parent_node.operation not in ("merge", "nomerge"):
						continue
					unsatisfied = \
						graph.child_nodes(parent_node,
						ignore_priority=DepPrioritySatisfiedRange.ignore_soft)
					if pkg in unsatisfied:
						unsatisfied_parents[parent_node] = parent_node
						unsatisfied_stack.append(parent_node)

			pruned_mergelist = []
			for x in mergelist:
				if isinstance(x, list) and \
					tuple(x) not in unsatisfied_parents:
					pruned_mergelist.append(x)

			# If the mergelist doesn't shrink then this loop is infinite.
			if len(pruned_mergelist) == len(mergelist):
				# This happens if a package can't be dropped because
				# it's already installed, but it has unsatisfied PDEPEND.
				raise
			mergelist[:] = pruned_mergelist

			# Exclude installed packages that have been removed from the graph due
			# to failure to build/install runtime dependencies after the dependent
			# package has already been installed.
			dropped_tasks.update(pkg for pkg in \
				unsatisfied_parents if pkg.operation != "nomerge")
			mydepgraph.break_refs(unsatisfied_parents)

			del e, graph, traversed_nodes, \
				unsatisfied_parents, unsatisfied_stack
			continue
		else:
			break
	return (success, mydepgraph, dropped_tasks)

def action_build(settings, trees, mtimedb,
	myopts, myaction, myfiles, spinner):

	# validate the state of the resume data
	# so that we can make assumptions later.
	for k in ("resume", "resume_backup"):
		if k not in mtimedb:
			continue
		resume_data = mtimedb[k]
		if not isinstance(resume_data, dict):
			del mtimedb[k]
			continue
		mergelist = resume_data.get("mergelist")
		if not isinstance(mergelist, list):
			del mtimedb[k]
			continue
		for x in mergelist:
			if not (isinstance(x, list) and len(x) == 4):
				continue
			pkg_type, pkg_root, pkg_key, pkg_action = x
			if pkg_root not in trees:
				# Current $ROOT setting differs,
				# so the list must be stale.
				mergelist = None
				break
		if not mergelist:
			del mtimedb[k]
			continue
		resume_opts = resume_data.get("myopts")
		if not isinstance(resume_opts, (dict, list)):
			del mtimedb[k]
			continue
		favorites = resume_data.get("favorites")
		if not isinstance(favorites, list):
			del mtimedb[k]
			continue

	resume = False
	if "--resume" in myopts and \
		("resume" in mtimedb or
		"resume_backup" in mtimedb):
		resume = True
		if "resume" not in mtimedb:
			mtimedb["resume"] = mtimedb["resume_backup"]
			del mtimedb["resume_backup"]
			mtimedb.commit()
		# "myopts" is a list for backward compatibility.
		resume_opts = mtimedb["resume"].get("myopts", [])
		if isinstance(resume_opts, list):
			resume_opts = dict((k,True) for k in resume_opts)
		for opt in ("--ask", "--color", "--skipfirst", "--tree"):
			resume_opts.pop(opt, None)
		myopts.update(resume_opts)

		if "--debug" in myopts:
			writemsg_level("myopts %s\n" % (myopts,))

		# Adjust config according to options of the command being resumed.
		for myroot in trees:
			mysettings =  trees[myroot]["vartree"].settings
			mysettings.unlock()
			adjust_config(myopts, mysettings)
			mysettings.lock()
			del myroot, mysettings

	ldpath_mtimes = mtimedb["ldpath"]
	favorites=[]
	merge_count = 0
	buildpkgonly = "--buildpkgonly" in myopts
	pretend = "--pretend" in myopts
	fetchonly = "--fetchonly" in myopts or "--fetch-all-uri" in myopts
	ask = "--ask" in myopts
	nodeps = "--nodeps" in myopts
	oneshot = "--oneshot" in myopts or "--onlydeps" in myopts
	tree = "--tree" in myopts
	if nodeps and tree:
		tree = False
		del myopts["--tree"]
		portage.writemsg(colorize("WARN", " * ") + \
			"--tree is broken with --nodeps. Disabling...\n")
	debug = "--debug" in myopts
	verbose = "--verbose" in myopts
	quiet = "--quiet" in myopts
	if pretend or fetchonly:
		# make the mtimedb readonly
		mtimedb.filename = None
	if '--digest' in myopts or 'digest' in settings.features:
		if '--digest' in myopts:
			msg = "The --digest option"
		else:
			msg = "The FEATURES=digest setting"

		msg += " can prevent corruption from being" + \
			" noticed. The `repoman manifest` command is the preferred" + \
			" way to generate manifests and it is capable of doing an" + \
			" entire repository or category at once."
		prefix = bad(" * ")
		writemsg(prefix + "\n")
		from textwrap import wrap
		for line in wrap(msg, 72):
			writemsg("%s%s\n" % (prefix, line))
		writemsg(prefix + "\n")

	if "--quiet" not in myopts and \
		("--pretend" in myopts or "--ask" in myopts or \
		"--tree" in myopts or "--verbose" in myopts):
		action = ""
		if "--fetchonly" in myopts or "--fetch-all-uri" in myopts:
			action = "fetched"
		elif "--buildpkgonly" in myopts:
			action = "built"
		else:
			action = "merged"
		if "--tree" in myopts and action != "fetched": # Tree doesn't work with fetching
			print
			print darkgreen("These are the packages that would be %s, in reverse order:") % action
			print
		else:
			print
			print darkgreen("These are the packages that would be %s, in order:") % action
			print

	show_spinner = "--quiet" not in myopts and "--nodeps" not in myopts
	if not show_spinner:
		spinner.update = spinner.update_quiet

	if resume:
		favorites = mtimedb["resume"].get("favorites")
		if not isinstance(favorites, list):
			favorites = []

		if show_spinner:
			print "Calculating dependencies  ",
		myparams = create_depgraph_params(myopts, myaction)

		resume_data = mtimedb["resume"]
		mergelist = resume_data["mergelist"]
		if mergelist and "--skipfirst" in myopts:
			for i, task in enumerate(mergelist):
				if isinstance(task, list) and \
					task and task[-1] == "merge":
					del mergelist[i]
					break

		success = False
		mydepgraph = None
		try:
			success, mydepgraph, dropped_tasks = resume_depgraph(
				settings, trees, mtimedb, myopts, myparams, spinner)
		except (portage.exception.PackageNotFound,
			depgraph.UnsatisfiedResumeDep), e:
			if isinstance(e, depgraph.UnsatisfiedResumeDep):
				mydepgraph = e.depgraph
			if show_spinner:
				print
			from textwrap import wrap
			from portage.output import EOutput
			out = EOutput()

			resume_data = mtimedb["resume"]
			mergelist = resume_data.get("mergelist")
			if not isinstance(mergelist, list):
				mergelist = []
			if mergelist and debug or (verbose and not quiet):
				out.eerror("Invalid resume list:")
				out.eerror("")
				indent = "  "
				for task in mergelist:
					if isinstance(task, list):
						out.eerror(indent + str(tuple(task)))
				out.eerror("")

			if isinstance(e, depgraph.UnsatisfiedResumeDep):
				out.eerror("One or more packages are either masked or " + \
					"have missing dependencies:")
				out.eerror("")
				indent = "  "
				for dep in e.value:
					if dep.atom is None:
						out.eerror(indent + "Masked package:")
						out.eerror(2 * indent + str(dep.parent))
						out.eerror("")
					else:
						out.eerror(indent + str(dep.atom) + " pulled in by:")
						out.eerror(2 * indent + str(dep.parent))
						out.eerror("")
				msg = "The resume list contains packages " + \
					"that are either masked or have " + \
					"unsatisfied dependencies. " + \
					"Please restart/continue " + \
					"the operation manually, or use --skipfirst " + \
					"to skip the first package in the list and " + \
					"any other packages that may be " + \
					"masked or have missing dependencies."
				for line in wrap(msg, 72):
					out.eerror(line)
			elif isinstance(e, portage.exception.PackageNotFound):
				out.eerror("An expected package is " + \
					"not available: %s" % str(e))
				out.eerror("")
				msg = "The resume list contains one or more " + \
					"packages that are no longer " + \
					"available. Please restart/continue " + \
					"the operation manually."
				for line in wrap(msg, 72):
					out.eerror(line)
		else:
			if show_spinner:
				print "\b\b... done!"

		if success:
			if dropped_tasks:
				portage.writemsg("!!! One or more packages have been " + \
					"dropped due to\n" + \
					"!!! masking or unsatisfied dependencies:\n\n",
					noiselevel=-1)
				for task in dropped_tasks:
					portage.writemsg("  " + str(task) + "\n", noiselevel=-1)
				portage.writemsg("\n", noiselevel=-1)
			del dropped_tasks
		else:
			if mydepgraph is not None:
				mydepgraph.display_problems()
			if not (ask or pretend):
				# delete the current list and also the backup
				# since it's probably stale too.
				for k in ("resume", "resume_backup"):
					mtimedb.pop(k, None)
				mtimedb.commit()

			return 1
	else:
		if ("--resume" in myopts):
			print darkgreen("emerge: It seems we have nothing to resume...")
			return os.EX_OK

		myparams = create_depgraph_params(myopts, myaction)
		if "--quiet" not in myopts and "--nodeps" not in myopts:
			print "Calculating dependencies  ",
			sys.stdout.flush()
		mydepgraph = depgraph(settings, trees, myopts, myparams, spinner)
		try:
			retval, favorites = mydepgraph.select_files(myfiles)
		except portage.exception.PackageNotFound, e:
			portage.writemsg("\n!!! %s\n" % str(e), noiselevel=-1)
			return 1
		except portage.exception.PackageSetNotFound, e:
			root_config = trees[settings["ROOT"]]["root_config"]
			display_missing_pkg_set(root_config, e.value)
			return 1
		if show_spinner:
			print "\b\b... done!"
		if not retval:
			mydepgraph.display_problems()
			return 1

	if "--pretend" not in myopts and \
		("--ask" in myopts or "--tree" in myopts or \
		"--verbose" in myopts) and \
		not ("--quiet" in myopts and "--ask" not in myopts):
		if "--resume" in myopts:
			mymergelist = mydepgraph.altlist()
			if len(mymergelist) == 0:
				print colorize("INFORM", "emerge: It seems we have nothing to resume...")
				return os.EX_OK
			favorites = mtimedb["resume"]["favorites"]
			retval = mydepgraph.display(
				mydepgraph.altlist(reversed=tree),
				favorites=favorites)
			mydepgraph.display_problems()
			if retval != os.EX_OK:
				return retval
			prompt="Would you like to resume merging these packages?"
		else:
			retval = mydepgraph.display(
				mydepgraph.altlist(reversed=("--tree" in myopts)),
				favorites=favorites)
			mydepgraph.display_problems()
			if retval != os.EX_OK:
				return retval
			mergecount=0
			for x in mydepgraph.altlist():
				if isinstance(x, Package) and x.operation == "merge":
					mergecount += 1

			if mergecount==0:
				sets = trees[settings["ROOT"]]["root_config"].sets
				world_candidates = None
				if "--noreplace" in myopts and \
					not oneshot and favorites:
					# Sets that are not world candidates are filtered
					# out here since the favorites list needs to be
					# complete for depgraph.loadResumeCommand() to
					# operate correctly.
					world_candidates = [x for x in favorites \
						if not (x.startswith(SETPREFIX) and \
						not sets[x[1:]].world_candidate)]
				if "--noreplace" in myopts and \
					not oneshot and world_candidates:
					print
					for x in world_candidates:
						print " %s %s" % (good("*"), x)
					prompt="Would you like to add these packages to your world favorites?"
				elif settings["AUTOCLEAN"] and "yes"==settings["AUTOCLEAN"]:
					prompt="Nothing to merge; would you like to auto-clean packages?"
				else:
					print
					print "Nothing to merge; quitting."
					print
					return os.EX_OK
			elif "--fetchonly" in myopts or "--fetch-all-uri" in myopts:
				prompt="Would you like to fetch the source files for these packages?"
			else:
				prompt="Would you like to merge these packages?"
		print
		if "--ask" in myopts and userquery(prompt) == "No":
			print
			print "Quitting."
			print
			return os.EX_OK
		# Don't ask again (e.g. when auto-cleaning packages after merge)
		myopts.pop("--ask", None)

	if ("--pretend" in myopts) and not ("--fetchonly" in myopts or "--fetch-all-uri" in myopts):
		if ("--resume" in myopts):
			mymergelist = mydepgraph.altlist()
			if len(mymergelist) == 0:
				print colorize("INFORM", "emerge: It seems we have nothing to resume...")
				return os.EX_OK
			favorites = mtimedb["resume"]["favorites"]
			retval = mydepgraph.display(
				mydepgraph.altlist(reversed=tree),
				favorites=favorites)
			mydepgraph.display_problems()
			if retval != os.EX_OK:
				return retval
		else:
			retval = mydepgraph.display(
				mydepgraph.altlist(reversed=("--tree" in myopts)),
				favorites=favorites)
			mydepgraph.display_problems()
			if retval != os.EX_OK:
				return retval
			if "--buildpkgonly" in myopts:
				graph_copy = mydepgraph.digraph.clone()
				removed_nodes = set()
				for node in graph_copy:
					if not isinstance(node, Package) or \
						node.operation == "nomerge":
						removed_nodes.add(node)
				graph_copy.difference_update(removed_nodes)
				if not graph_copy.hasallzeros(ignore_priority = \
					DepPrioritySatisfiedRange.ignore_medium):
					print "\n!!! --buildpkgonly requires all dependencies to be merged."
					print "!!! You have to merge the dependencies before you can build this package.\n"
					return 1
	else:
		if "--buildpkgonly" in myopts:
			graph_copy = mydepgraph.digraph.clone()
			removed_nodes = set()
			for node in graph_copy:
				if not isinstance(node, Package) or \
					node.operation == "nomerge":
					removed_nodes.add(node)
			graph_copy.difference_update(removed_nodes)
			if not graph_copy.hasallzeros(ignore_priority = \
				DepPrioritySatisfiedRange.ignore_medium):
				print "\n!!! --buildpkgonly requires all dependencies to be merged."
				print "!!! Cannot merge requested packages. Merge deps and try again.\n"
				return 1

		if ("--resume" in myopts):
			favorites=mtimedb["resume"]["favorites"]
			mymergelist = mydepgraph.altlist()
			mydepgraph.break_refs(mymergelist)
			mergetask = Scheduler(settings, trees, mtimedb, myopts,
				spinner, mymergelist, favorites, mydepgraph.schedulerGraph())
			del mydepgraph, mymergelist
			clear_caches(trees)

			retval = mergetask.merge()
			merge_count = mergetask.curval
		else:
			if "resume" in mtimedb and \
			"mergelist" in mtimedb["resume"] and \
			len(mtimedb["resume"]["mergelist"]) > 1:
				mtimedb["resume_backup"] = mtimedb["resume"]
				del mtimedb["resume"]
				mtimedb.commit()
			mtimedb["resume"]={}
			# Stored as a dict starting with portage-2.1.6_rc1, and supported
			# by >=portage-2.1.3_rc8. Versions <portage-2.1.3_rc8 only support
			# a list type for options.
			mtimedb["resume"]["myopts"] = myopts.copy()

			# Convert Atom instances to plain str.
			mtimedb["resume"]["favorites"] = [str(x) for x in favorites]

			pkglist = mydepgraph.altlist()
			mydepgraph.saveNomergeFavorites()
			mydepgraph.break_refs(pkglist)
			mergetask = Scheduler(settings, trees, mtimedb, myopts,
				spinner, pkglist, favorites, mydepgraph.schedulerGraph())
			del mydepgraph, pkglist
			clear_caches(trees)

			retval = mergetask.merge()
			merge_count = mergetask.curval

		if retval == os.EX_OK and not (buildpkgonly or fetchonly or pretend):
			if "yes" == settings.get("AUTOCLEAN"):
				portage.writemsg_stdout(">>> Auto-cleaning packages...\n")
				unmerge(trees[settings["ROOT"]]["root_config"],
					myopts, "clean", [],
					ldpath_mtimes, autoclean=1)
			else:
				portage.writemsg_stdout(colorize("WARN", "WARNING:")
					+ " AUTOCLEAN is disabled.  This can cause serious"
					+ " problems due to overlapping packages.\n")
			trees[settings["ROOT"]]["vartree"].dbapi.plib_registry.pruneNonExisting()

		return retval

def multiple_actions(action1, action2):
	sys.stderr.write("\n!!! Multiple actions requested... Please choose one only.\n")
	sys.stderr.write("!!! '%s' or '%s'\n\n" % (action1, action2))
	sys.exit(1)

def insert_optional_args(args):
	"""
	Parse optional arguments and insert a value if one has
	not been provided. This is done before feeding the args
	to the optparse parser since that parser does not support
	this feature natively.
	"""

	new_args = []
	jobs_opts = ("-j", "--jobs")
	arg_stack = args[:]
	arg_stack.reverse()
	while arg_stack:
		arg = arg_stack.pop()

		short_job_opt = bool("j" in arg and arg[:1] == "-" and arg[:2] != "--")
		if not (short_job_opt or arg in jobs_opts):
			new_args.append(arg)
			continue

		# Insert an empty placeholder in order to
		# satisfy the requirements of optparse.

		new_args.append("--jobs")
		job_count = None
		saved_opts = None
		if short_job_opt and len(arg) > 2:
			if arg[:2] == "-j":
				try:
					job_count = int(arg[2:])
				except ValueError:
					saved_opts = arg[2:]
			else:
				job_count = "True"
				saved_opts = arg[1:].replace("j", "")

		if job_count is None and arg_stack:
			try:
				job_count = int(arg_stack[-1])
			except ValueError:
				pass
			else:
				# Discard the job count from the stack
				# since we're consuming it here.
				arg_stack.pop()

		if job_count is None:
			# unlimited number of jobs
			new_args.append("True")
		else:
			new_args.append(str(job_count))

		if saved_opts is not None:
			new_args.append("-" + saved_opts)

	return new_args

def parse_opts(tmpcmdline, silent=False):
	myaction=None
	myopts = {}
	myfiles=[]

	global actions, options, shortmapping

	longopt_aliases = {"--cols":"--columns", "--skip-first":"--skipfirst"}
	argument_options = {
		"--config-root": {
			"help":"specify the location for portage configuration files",
			"action":"store"
		},
		"--color": {
			"help":"enable or disable color output",
			"type":"choice",
			"choices":("y", "n")
		},

		"--jobs": {

			"help"   : "Specifies the number of packages to build " + \
				"simultaneously.",

			"action" : "store"
		},

		"--load-average": {

			"help"   :"Specifies that no new builds should be started " + \
				"if there are other builds running and the load average " + \
				"is at least LOAD (a floating-point number).",

			"action" : "store"
		},

		"--with-bdeps": {
			"help":"include unnecessary build time dependencies",
			"type":"choice",
			"choices":("y", "n")
		},
		"--reinstall": {
			"help":"specify conditions to trigger package reinstallation",
			"type":"choice",
			"choices":["changed-use"]
		}
	}

	from optparse import OptionParser
	parser = OptionParser()
	if parser.has_option("--help"):
		parser.remove_option("--help")

	for action_opt in actions:
		parser.add_option("--" + action_opt, action="store_true",
			dest=action_opt.replace("-", "_"), default=False)
	for myopt in options:
		parser.add_option(myopt, action="store_true",
			dest=myopt.lstrip("--").replace("-", "_"), default=False)
	for shortopt, longopt in shortmapping.iteritems():
		parser.add_option("-" + shortopt, action="store_true",
			dest=longopt.lstrip("--").replace("-", "_"), default=False)
	for myalias, myopt in longopt_aliases.iteritems():
		parser.add_option(myalias, action="store_true",
			dest=myopt.lstrip("--").replace("-", "_"), default=False)

	for myopt, kwargs in argument_options.iteritems():
		parser.add_option(myopt,
			dest=myopt.lstrip("--").replace("-", "_"), **kwargs)

	tmpcmdline = insert_optional_args(tmpcmdline)

	myoptions, myargs = parser.parse_args(args=tmpcmdline)

	if myoptions.jobs:
		jobs = None
		if myoptions.jobs == "True":
			jobs = True
		else:
			try:
				jobs = int(myoptions.jobs)
			except ValueError:
				jobs = -1

		if jobs is not True and \
			jobs < 1:
			jobs = None
			if not silent:
				writemsg("!!! Invalid --jobs parameter: '%s'\n" % \
					(myoptions.jobs,), noiselevel=-1)

		myoptions.jobs = jobs

	if myoptions.load_average:
		try:
			load_average = float(myoptions.load_average)
		except ValueError:
			load_average = 0.0

		if load_average <= 0.0:
			load_average = None
			if not silent:
				writemsg("!!! Invalid --load-average parameter: '%s'\n" % \
					(myoptions.load_average,), noiselevel=-1)

		myoptions.load_average = load_average

	for myopt in options:
		v = getattr(myoptions, myopt.lstrip("--").replace("-", "_"))
		if v:
			myopts[myopt] = True

	for myopt in argument_options:
		v = getattr(myoptions, myopt.lstrip("--").replace("-", "_"), None)
		if v is not None:
			myopts[myopt] = v

	if myoptions.searchdesc:
		myoptions.search = True

	for action_opt in actions:
		v = getattr(myoptions, action_opt.replace("-", "_"))
		if v:
			if myaction:
				multiple_actions(myaction, action_opt)
				sys.exit(1)
			myaction = action_opt

	myfiles += myargs

	return myaction, myopts, myfiles

def validate_ebuild_environment(trees):
	for myroot in trees:
		settings = trees[myroot]["vartree"].settings
		settings.validate()

def clear_caches(trees):
	for d in trees.itervalues():
		d["porttree"].dbapi.melt()
		d["porttree"].dbapi._aux_cache.clear()
		d["bintree"].dbapi._aux_cache.clear()
		d["bintree"].dbapi._clear_cache()
		d["vartree"].dbapi.linkmap._clear_cache()
	portage.dircache.clear()
	gc.collect()

def load_emerge_config(trees=None):
	kwargs = {}
	for k, envvar in (("config_root", "PORTAGE_CONFIGROOT"), ("target_root", "ROOT")):
		v = os.environ.get(envvar, None)
		if v and v.strip():
			kwargs[k] = v
	trees = portage.create_trees(trees=trees, **kwargs)

	for root, root_trees in trees.iteritems():
		settings = root_trees["vartree"].settings
		setconfig = load_default_config(settings, root_trees)
		root_trees["root_config"] = RootConfig(settings, root_trees, setconfig)

	settings = trees["/"]["vartree"].settings

	for myroot in trees:
		if myroot != "/":
			settings = trees[myroot]["vartree"].settings
			break

	mtimedbfile = os.path.join("/", portage.CACHE_PATH.lstrip(os.path.sep), "mtimedb")
	mtimedb = portage.MtimeDB(mtimedbfile)
	
	return settings, trees, mtimedb

def adjust_config(myopts, settings):
	"""Make emerge specific adjustments to the config."""

	# To enhance usability, make some vars case insensitive by forcing them to
	# lower case.
	for myvar in ("AUTOCLEAN", "NOCOLOR"):
		if myvar in settings:
			settings[myvar] = settings[myvar].lower()
			settings.backup_changes(myvar)
	del myvar

	# Kill noauto as it will break merges otherwise.
	if "noauto" in settings.features:
		while "noauto" in settings.features:
			settings.features.remove("noauto")
		settings["FEATURES"] = " ".join(settings.features)
		settings.backup_changes("FEATURES")

	CLEAN_DELAY = 5
	try:
		CLEAN_DELAY = int(settings.get("CLEAN_DELAY", str(CLEAN_DELAY)))
	except ValueError, e:
		portage.writemsg("!!! %s\n" % str(e), noiselevel=-1)
		portage.writemsg("!!! Unable to parse integer: CLEAN_DELAY='%s'\n" % \
			settings["CLEAN_DELAY"], noiselevel=-1)
	settings["CLEAN_DELAY"] = str(CLEAN_DELAY)
	settings.backup_changes("CLEAN_DELAY")

	EMERGE_WARNING_DELAY = 10
	try:
		EMERGE_WARNING_DELAY = int(settings.get(
			"EMERGE_WARNING_DELAY", str(EMERGE_WARNING_DELAY)))
	except ValueError, e:
		portage.writemsg("!!! %s\n" % str(e), noiselevel=-1)
		portage.writemsg("!!! Unable to parse integer: EMERGE_WARNING_DELAY='%s'\n" % \
			settings["EMERGE_WARNING_DELAY"], noiselevel=-1)
	settings["EMERGE_WARNING_DELAY"] = str(EMERGE_WARNING_DELAY)
	settings.backup_changes("EMERGE_WARNING_DELAY")

	if "--quiet" in myopts:
		settings["PORTAGE_QUIET"]="1"
		settings.backup_changes("PORTAGE_QUIET")

	if "--verbose" in myopts:
		settings["PORTAGE_VERBOSE"] = "1"
		settings.backup_changes("PORTAGE_VERBOSE")

	# Set so that configs will be merged regardless of remembered status
	if ("--noconfmem" in myopts):
		settings["NOCONFMEM"]="1"
		settings.backup_changes("NOCONFMEM")

	# Set various debug markers... They should be merged somehow.
	PORTAGE_DEBUG = 0
	try:
		PORTAGE_DEBUG = int(settings.get("PORTAGE_DEBUG", str(PORTAGE_DEBUG)))
		if PORTAGE_DEBUG not in (0, 1):
			portage.writemsg("!!! Invalid value: PORTAGE_DEBUG='%i'\n" % \
				PORTAGE_DEBUG, noiselevel=-1)
			portage.writemsg("!!! PORTAGE_DEBUG must be either 0 or 1\n",
				noiselevel=-1)
			PORTAGE_DEBUG = 0
	except ValueError, e:
		portage.writemsg("!!! %s\n" % str(e), noiselevel=-1)
		portage.writemsg("!!! Unable to parse integer: PORTAGE_DEBUG='%s'\n" %\
			settings["PORTAGE_DEBUG"], noiselevel=-1)
		del e
	if "--debug" in myopts:
		PORTAGE_DEBUG = 1
	settings["PORTAGE_DEBUG"] = str(PORTAGE_DEBUG)
	settings.backup_changes("PORTAGE_DEBUG")

	if settings.get("NOCOLOR") not in ("yes","true"):
		portage.output.havecolor = 1

	"""The explicit --color < y | n > option overrides the NOCOLOR environment
	variable and stdout auto-detection."""
	if "--color" in myopts:
		if "y" == myopts["--color"]:
			portage.output.havecolor = 1
			settings["NOCOLOR"] = "false"
		else:
			portage.output.havecolor = 0
			settings["NOCOLOR"] = "true"
		settings.backup_changes("NOCOLOR")
	elif not sys.stdout.isatty() and settings.get("NOCOLOR") != "no":
		portage.output.havecolor = 0
		settings["NOCOLOR"] = "true"
		settings.backup_changes("NOCOLOR")

def apply_priorities(settings):
	ionice(settings)
	nice(settings)

def nice(settings):
	try:
		os.nice(int(settings.get("PORTAGE_NICENESS", "0")))
	except (OSError, ValueError), e:
		out = portage.output.EOutput()
		out.eerror("Failed to change nice value to '%s'" % \
			settings["PORTAGE_NICENESS"])
		out.eerror("%s\n" % str(e))

def ionice(settings):

	ionice_cmd = settings.get("PORTAGE_IONICE_COMMAND")
	if ionice_cmd:
		ionice_cmd = shlex.split(ionice_cmd)
	if not ionice_cmd:
		return

	from portage.util import varexpand
	variables = {"PID" : str(os.getpid())}
	cmd = [varexpand(x, mydict=variables) for x in ionice_cmd]

	try:
		rval = portage.process.spawn(cmd, env=os.environ)
	except portage.exception.CommandNotFound:
		# The OS kernel probably doesn't support ionice,
		# so return silently.
		return

	if rval != os.EX_OK:
		out = portage.output.EOutput()
		out.eerror("PORTAGE_IONICE_COMMAND returned %d" % (rval,))
		out.eerror("See the make.conf(5) man page for PORTAGE_IONICE_COMMAND usage instructions.")

def display_missing_pkg_set(root_config, set_name):

	msg = []
	msg.append(("emerge: There are no sets to satisfy '%s'. " + \
		"The following sets exist:") % \
		colorize("INFORM", set_name))
	msg.append("")

	for s in sorted(root_config.sets):
		msg.append("    %s" % s)
	msg.append("")

	writemsg_level("".join("%s\n" % l for l in msg),
		level=logging.ERROR, noiselevel=-1)

def expand_set_arguments(myfiles, myaction, root_config):
	retval = os.EX_OK
	setconfig = root_config.setconfig

	sets = setconfig.getSets()

	# In order to know exactly which atoms/sets should be added to the
	# world file, the depgraph performs set expansion later. It will get
	# confused about where the atoms came from if it's not allowed to
	# expand them itself.
	do_not_expand = (None, )
	newargs = []
	for a in myfiles:
		if a in ("system", "world"):
			newargs.append(SETPREFIX+a)
		else:
			newargs.append(a)
	myfiles = newargs
	del newargs
	newargs = []

	# separators for set arguments
	ARG_START = "{"
	ARG_END = "}"

	# WARNING: all operators must be of equal length
	IS_OPERATOR = "/@"
	DIFF_OPERATOR = "-@"
	UNION_OPERATOR = "+@"
	
	for i in range(0, len(myfiles)):
		if myfiles[i].startswith(SETPREFIX):
			start = 0
			end = 0
			x = myfiles[i][len(SETPREFIX):]
			newset = ""
			while x:
				start = x.find(ARG_START)
				end = x.find(ARG_END)
				if start > 0 and start < end:
					namepart = x[:start]
					argpart = x[start+1:end]
				
					# TODO: implement proper quoting
					args = argpart.split(",")
					options = {}
					for a in args:
						if "=" in a:
							k, v  = a.split("=", 1)
							options[k] = v
						else:
							options[a] = "True"
					setconfig.update(namepart, options)
					newset += (x[:start-len(namepart)]+namepart)
					x = x[end+len(ARG_END):]
				else:
					newset += x
					x = ""
			myfiles[i] = SETPREFIX+newset
				
	sets = setconfig.getSets()

	# display errors that occured while loading the SetConfig instance
	for e in setconfig.errors:
		print colorize("BAD", "Error during set creation: %s" % e)
	
	# emerge relies on the existance of sets with names "world" and "system"
	required_sets = ("world", "system")
	missing_sets = []

	for s in required_sets:
		if s not in sets:
			missing_sets.append(s)
	if missing_sets:
		if len(missing_sets) > 2:
			missing_sets_str = ", ".join('"%s"' % s for s in missing_sets[:-1])
			missing_sets_str += ', and "%s"' % missing_sets[-1]
		elif len(missing_sets) == 2:
			missing_sets_str = '"%s" and "%s"' % tuple(missing_sets)
		else:
			missing_sets_str = '"%s"' % missing_sets[-1]
		msg = ["emerge: incomplete set configuration, " + \
			"missing set(s): %s" % missing_sets_str]
		if sets:
			msg.append("        sets defined: %s" % ", ".join(sets))
		msg.append("        This usually means that '%s'" % \
			(os.path.join(portage.const.GLOBAL_CONFIG_PATH, "sets.conf"),))
		msg.append("        is missing or corrupt.")
		for line in msg:
			writemsg_level(line + "\n", level=logging.ERROR, noiselevel=-1)
		return (None, 1)
	unmerge_actions = ("unmerge", "prune", "clean", "depclean")

	for a in myfiles:
		if a.startswith(SETPREFIX):
			# support simple set operations (intersection, difference and union)
			# on the commandline. Expressions are evaluated strictly left-to-right
			if IS_OPERATOR in a or DIFF_OPERATOR in a or UNION_OPERATOR in a:
				expression = a[len(SETPREFIX):]
				expr_sets = []
				expr_ops = []
				while IS_OPERATOR in expression or DIFF_OPERATOR in expression or UNION_OPERATOR in expression:
					is_pos = expression.rfind(IS_OPERATOR)
					diff_pos = expression.rfind(DIFF_OPERATOR)
					union_pos = expression.rfind(UNION_OPERATOR)
					op_pos = max(is_pos, diff_pos, union_pos)
					s1 = expression[:op_pos]
					s2 = expression[op_pos+len(IS_OPERATOR):]
					op = expression[op_pos:op_pos+len(IS_OPERATOR)]
					if not s2 in sets:
						display_missing_pkg_set(root_config, s2)
						return (None, 1)
					expr_sets.insert(0, s2)
					expr_ops.insert(0, op)
					expression = s1
				if not expression in sets:
					display_missing_pkg_set(root_config, expression)
					return (None, 1)
				expr_sets.insert(0, expression)
				result = set(setconfig.getSetAtoms(expression))
				for i in range(0, len(expr_ops)):
					s2 = setconfig.getSetAtoms(expr_sets[i+1])
					if expr_ops[i] == IS_OPERATOR:
						result.intersection_update(s2)
					elif expr_ops[i] == DIFF_OPERATOR:
						result.difference_update(s2)
					elif expr_ops[i] == UNION_OPERATOR:
						result.update(s2)
					else:
						raise NotImplementedError("unknown set operator %s" % expr_ops[i])
				newargs.extend(result)
			else:			
				s = a[len(SETPREFIX):]
				if s not in sets:
					display_missing_pkg_set(root_config, s)
					return (None, 1)
				setconfig.active.append(s)
				try:
					set_atoms = setconfig.getSetAtoms(s)
				except portage.exception.PackageSetNotFound, e:
					writemsg_level(("emerge: the given set '%s' " + \
						"contains a non-existent set named '%s'.\n") % \
						(s, e), level=logging.ERROR, noiselevel=-1)
					return (None, 1)
				if myaction in unmerge_actions and \
						not sets[s].supportsOperation("unmerge"):
					sys.stderr.write("emerge: the given set '%s' does " % s + \
						"not support unmerge operations\n")
					retval = 1
				elif not set_atoms:
					print "emerge: '%s' is an empty set" % s
				elif myaction not in do_not_expand:
					newargs.extend(set_atoms)
				else:
					newargs.append(SETPREFIX+s)
				for e in sets[s].errors:
					print e
		else:
			newargs.append(a)
	return (newargs, retval)

def repo_name_check(trees):
	missing_repo_names = set()
	for root, root_trees in trees.iteritems():
		if "porttree" in root_trees:
			portdb = root_trees["porttree"].dbapi
			missing_repo_names.update(portdb.porttrees)
			repos = portdb.getRepositories()
			for r in repos:
				missing_repo_names.discard(portdb.getRepositoryPath(r))
			if portdb.porttree_root in missing_repo_names and \
				not os.path.exists(os.path.join(
				portdb.porttree_root, "profiles")):
				# This is normal if $PORTDIR happens to be empty,
				# so don't warn about it.
				missing_repo_names.remove(portdb.porttree_root)

	if missing_repo_names:
		msg = []
		msg.append("WARNING: One or more repositories " + \
			"have missing repo_name entries:")
		msg.append("")
		for p in missing_repo_names:
			msg.append("\t%s/profiles/repo_name" % (p,))
		msg.append("")
		msg.extend(textwrap.wrap("NOTE: Each repo_name entry " + \
			"should be a plain text file containing a unique " + \
			"name for the repository on the first line.", 70))
		writemsg_level("".join("%s\n" % l for l in msg),
			level=logging.WARNING, noiselevel=-1)

	return bool(missing_repo_names)

def config_protect_check(trees):
	for root, root_trees in trees.iteritems():
		if not root_trees["root_config"].settings.get("CONFIG_PROTECT"):
			msg = "!!! CONFIG_PROTECT is empty"
			if root != "/":
				msg += " for '%s'" % root
			writemsg_level(msg, level=logging.WARN, noiselevel=-1)

def ambiguous_package_name(arg, atoms, root_config, spinner, myopts):

	if "--quiet" in myopts:
		print "!!! The short ebuild name \"%s\" is ambiguous. Please specify" % arg
		print "!!! one of the following fully-qualified ebuild names instead:\n"
		for cp in sorted(set(portage.dep_getkey(atom) for atom in atoms)):
			print "    " + colorize("INFORM", cp)
		return

	s = search(root_config, spinner, "--searchdesc" in myopts,
		"--quiet" not in myopts, "--usepkg" in myopts,
		"--usepkgonly" in myopts)
	null_cp = portage.dep_getkey(insert_category_into_atom(
		arg, "null"))
	cat, atom_pn = portage.catsplit(null_cp)
	s.searchkey = atom_pn
	for cp in sorted(set(portage.dep_getkey(atom) for atom in atoms)):
		s.addCP(cp)
	s.output()
	print "!!! The short ebuild name \"%s\" is ambiguous. Please specify" % arg
	print "!!! one of the above fully-qualified ebuild names instead.\n"

def profile_check(trees, myaction, myopts):
	if myaction in ("info", "sync"):
		return os.EX_OK
	elif "--version" in myopts or "--help" in myopts:
		return os.EX_OK
	for root, root_trees in trees.iteritems():
		if root_trees["root_config"].settings.profiles:
			continue
		# generate some profile related warning messages
		validate_ebuild_environment(trees)
		msg = "If you have just changed your profile configuration, you " + \
			"should revert back to the previous configuration. Due to " + \
			"your current profile being invalid, allowed actions are " + \
			"limited to --help, --info, --sync, and --version."
		writemsg_level("".join("!!! %s\n" % l for l in textwrap.wrap(msg, 70)),
			level=logging.ERROR, noiselevel=-1)
		return 1
	return os.EX_OK

def emerge_main():
	global portage	# NFC why this is necessary now - genone
	portage._disable_legacy_globals()
	# Disable color until we're sure that it should be enabled (after
	# EMERGE_DEFAULT_OPTS has been parsed).
	portage.output.havecolor = 0
	# This first pass is just for options that need to be known as early as
	# possible, such as --config-root.  They will be parsed again later,
	# together with EMERGE_DEFAULT_OPTS (which may vary depending on the
	# the value of --config-root).
	myaction, myopts, myfiles = parse_opts(sys.argv[1:], silent=True)
	if "--debug" in myopts:
		os.environ["PORTAGE_DEBUG"] = "1"
	if "--config-root" in myopts:
		os.environ["PORTAGE_CONFIGROOT"] = myopts["--config-root"]

	# Portage needs to ensure a sane umask for the files it creates.
	os.umask(022)
	settings, trees, mtimedb = load_emerge_config()
	portdb = trees[settings["ROOT"]]["porttree"].dbapi
	rval = profile_check(trees, myaction, myopts)
	if rval != os.EX_OK:
		return rval

	if portage._global_updates(trees, mtimedb["updates"]):
		mtimedb.commit()
		# Reload the whole config from scratch.
		settings, trees, mtimedb = load_emerge_config(trees=trees)
		portdb = trees[settings["ROOT"]]["porttree"].dbapi

	xterm_titles = "notitles" not in settings.features

	tmpcmdline = []
	if "--ignore-default-opts" not in myopts:
		tmpcmdline.extend(settings["EMERGE_DEFAULT_OPTS"].split())
	tmpcmdline.extend(sys.argv[1:])
	myaction, myopts, myfiles = parse_opts(tmpcmdline)

	if "--digest" in myopts:
		os.environ["FEATURES"] = os.environ.get("FEATURES","") + " digest"
		# Reload the whole config from scratch so that the portdbapi internal
		# config is updated with new FEATURES.
		settings, trees, mtimedb = load_emerge_config(trees=trees)
		portdb = trees[settings["ROOT"]]["porttree"].dbapi

	for myroot in trees:
		mysettings =  trees[myroot]["vartree"].settings
		mysettings.unlock()
		adjust_config(myopts, mysettings)
		if '--pretend' not in myopts and myaction in \
			(None, 'clean', 'depclean', 'prune', 'unmerge'):
			mysettings["PORTAGE_COUNTER_HASH"] = \
				trees[myroot]["vartree"].dbapi._counter_hash()
			mysettings.backup_changes("PORTAGE_COUNTER_HASH")
		mysettings.lock()
		del myroot, mysettings

	apply_priorities(settings)

	spinner = stdout_spinner()
	if "candy" in settings.features:
		spinner.update = spinner.update_scroll

	if "--quiet" not in myopts:
		portage.deprecated_profile_check(settings=settings)
		repo_name_check(trees)
		config_protect_check(trees)

	eclasses_overridden = {}
	for mytrees in trees.itervalues():
		mydb = mytrees["porttree"].dbapi
		# Freeze the portdbapi for performance (memoize all xmatch results).
		mydb.freeze()
		eclasses_overridden.update(mydb.eclassdb._master_eclasses_overridden)
	del mytrees, mydb

	if eclasses_overridden and \
		settings.get("PORTAGE_ECLASS_WARNING_ENABLE") != "0":
		prefix = bad(" * ")
		if len(eclasses_overridden) == 1:
			writemsg(prefix + "Overlay eclass overrides " + \
				"eclass from PORTDIR:\n", noiselevel=-1)
		else:
			writemsg(prefix + "Overlay eclasses override " + \
				"eclasses from PORTDIR:\n", noiselevel=-1)
		writemsg(prefix + "\n", noiselevel=-1)
		for eclass_name in sorted(eclasses_overridden):
			writemsg(prefix + "  '%s/%s.eclass'\n" % \
				(eclasses_overridden[eclass_name], eclass_name),
				noiselevel=-1)
		writemsg(prefix + "\n", noiselevel=-1)
		msg = "It is best to avoid overriding eclasses from PORTDIR " + \
		"because it will trigger invalidation of cached ebuild metadata " + \
		"that is distributed with the portage tree. If you must " + \
		"override eclasses from PORTDIR then you are advised to add " + \
		"FEATURES=\"metadata-transfer\" to /etc/make.conf and to run " + \
		"`emerge --regen` after each time that you run `emerge --sync`. " + \
		"Set PORTAGE_ECLASS_WARNING_ENABLE=\"0\" in /etc/make.conf if " + \
		"you would like to disable this warning."
		from textwrap import wrap
		for line in wrap(msg, 72):
			writemsg("%s%s\n" % (prefix, line), noiselevel=-1)

	if "moo" in myfiles:
		print """

  Larry loves Gentoo (""" + platform.system() + """)

 _______________________
< Have you mooed today? >
 -----------------------
        \   ^__^
         \  (oo)\_______
            (__)\       )\/\ 
                ||----w |
                ||     ||

"""

	for x in myfiles:
		ext = os.path.splitext(x)[1]
		if (ext == ".ebuild" or ext == ".tbz2") and os.path.exists(os.path.abspath(x)):
			print colorize("BAD", "\n*** emerging by path is broken and may not always work!!!\n")
			break

	root_config = trees[settings["ROOT"]]["root_config"]
	if myaction == "list-sets":
		sys.stdout.write("".join("%s\n" % s for s in sorted(root_config.sets)))
		sys.stdout.flush()
		return os.EX_OK

	# only expand sets for actions taking package arguments
	oldargs = myfiles[:]
	if myaction in ("clean", "config", "depclean", "info", "prune", "unmerge", None):
		myfiles, retval = expand_set_arguments(myfiles, myaction, root_config)
		if retval != os.EX_OK:
			return retval

		# Need to handle empty sets specially, otherwise emerge will react 
		# with the help message for empty argument lists
		if oldargs and not myfiles:
			print "emerge: no targets left after set expansion"
			return 0

	if ("--tree" in myopts) and ("--columns" in myopts):
		print "emerge: can't specify both of \"--tree\" and \"--columns\"."
		return 1

	if ("--quiet" in myopts):
		spinner.update = spinner.update_quiet
		portage.util.noiselimit = -1

	# Always create packages if FEATURES=buildpkg
	# Imply --buildpkg if --buildpkgonly
	if ("buildpkg" in settings.features) or ("--buildpkgonly" in myopts):
		if "--buildpkg" not in myopts:
			myopts["--buildpkg"] = True

	# Always try and fetch binary packages if FEATURES=getbinpkg
	if ("getbinpkg" in settings.features):
		myopts["--getbinpkg"] = True

	if "--buildpkgonly" in myopts:
		# --buildpkgonly will not merge anything, so
		# it cancels all binary package options.
		for opt in ("--getbinpkg", "--getbinpkgonly",
			"--usepkg", "--usepkgonly"):
			myopts.pop(opt, None)

	if "--fetch-all-uri" in myopts:
		myopts["--fetchonly"] = True

	if "--skipfirst" in myopts and "--resume" not in myopts:
		myopts["--resume"] = True

	if ("--getbinpkgonly" in myopts) and not ("--usepkgonly" in myopts):
		myopts["--usepkgonly"] = True

	if ("--getbinpkgonly" in myopts) and not ("--getbinpkg" in myopts):
		myopts["--getbinpkg"] = True

	if ("--getbinpkg" in myopts) and not ("--usepkg" in myopts):
		myopts["--usepkg"] = True

	# Also allow -K to apply --usepkg/-k
	if ("--usepkgonly" in myopts) and not ("--usepkg" in myopts):
		myopts["--usepkg"] = True

	# Allow -p to remove --ask
	if ("--pretend" in myopts) and ("--ask" in myopts):
		print ">>> --pretend disables --ask... removing --ask from options."
		del myopts["--ask"]

	# forbid --ask when not in a terminal
	# note: this breaks `emerge --ask | tee logfile`, but that doesn't work anyway.
	if ("--ask" in myopts) and (not sys.stdin.isatty()):
		portage.writemsg("!!! \"--ask\" should only be used in a terminal. Exiting.\n",
			noiselevel=-1)
		return 1

	if settings.get("PORTAGE_DEBUG", "") == "1":
		spinner.update = spinner.update_quiet
		portage.debug=1
		if "python-trace" in settings.features:
			import portage.debug
			portage.debug.set_trace(True)

	if not ("--quiet" in myopts):
		if not sys.stdout.isatty() or ("--nospinner" in myopts):
			spinner.update = spinner.update_basic

	if myaction == 'version':
		print getportageversion(settings["PORTDIR"], settings["ROOT"],
			settings.profile_path, settings["CHOST"],
			trees[settings["ROOT"]]["vartree"].dbapi)
		return 0
	elif "--help" in myopts:
		_emerge.help.help(myaction, myopts, portage.output.havecolor)
		return 0

	if "--debug" in myopts:
		print "myaction", myaction
		print "myopts", myopts

	if not myaction and not myfiles and "--resume" not in myopts:
		_emerge.help.help(myaction, myopts, portage.output.havecolor)
		return 1

	pretend = "--pretend" in myopts
	fetchonly = "--fetchonly" in myopts or "--fetch-all-uri" in myopts
	buildpkgonly = "--buildpkgonly" in myopts

	# check if root user is the current user for the actions where emerge needs this
	if portage.secpass < 2:
		# We've already allowed "--version" and "--help" above.
		if "--pretend" not in myopts and myaction not in ("search","info"):
			need_superuser = not \
				(fetchonly or \
				(buildpkgonly and secpass >= 1) or \
				myaction in ("metadata", "regen") or \
				(myaction == "sync" and os.access(settings["PORTDIR"], os.W_OK)))
			if portage.secpass < 1 or \
				need_superuser:
				if need_superuser:
					access_desc = "superuser"
				else:
					access_desc = "portage group"
				# Always show portage_group_warning() when only portage group
				# access is required but the user is not in the portage group.
				from portage.data import portage_group_warning
				if "--ask" in myopts:
					myopts["--pretend"] = True
					del myopts["--ask"]
					print ("%s access is required... " + \
						"adding --pretend to options.\n") % access_desc
					if portage.secpass < 1 and not need_superuser:
						portage_group_warning()
				else:
					sys.stderr.write(("emerge: %s access is " + \
						"required.\n\n") % access_desc)
					if portage.secpass < 1 and not need_superuser:
						portage_group_warning()
					return 1

	disable_emergelog = False
	for x in ("--pretend", "--fetchonly", "--fetch-all-uri"):
		if x in myopts:
			disable_emergelog = True
			break
	if myaction in ("search", "info"):
		disable_emergelog = True
	if disable_emergelog:
		""" Disable emergelog for everything except build or unmerge
		operations.  This helps minimize parallel emerge.log entries that can
		confuse log parsers.  We especially want it disabled during
		parallel-fetch, which uses --resume --fetchonly."""
		global emergelog
		def emergelog(*pargs, **kargs):
			pass

	if not "--pretend" in myopts:
		emergelog(xterm_titles, "Started emerge on: "+\
			time.strftime("%b %d, %Y %H:%M:%S", time.localtime()))
		myelogstr=""
		if myopts:
			myelogstr=" ".join(myopts)
		if myaction:
			myelogstr+=" "+myaction
		if myfiles:
			myelogstr += " " + " ".join(oldargs)
		emergelog(xterm_titles, " *** emerge " + myelogstr)
	del oldargs

	def emergeexitsig(signum, frame):
		signal.signal(signal.SIGINT, signal.SIG_IGN)
		signal.signal(signal.SIGTERM, signal.SIG_IGN)
		portage.util.writemsg("\n\nExiting on signal %(signal)s\n" % {"signal":signum})
		sys.exit(100+signum)
	signal.signal(signal.SIGINT, emergeexitsig)
	signal.signal(signal.SIGTERM, emergeexitsig)

	def emergeexit():
		"""This gets out final log message in before we quit."""
		if "--pretend" not in myopts:
			emergelog(xterm_titles, " *** terminating.")
		if "notitles" not in settings.features:
			xtermTitleReset()
	portage.atexit_register(emergeexit)

	if myaction in ("config", "metadata", "regen", "sync"):
		if "--pretend" in myopts:
			sys.stderr.write(("emerge: The '%s' action does " + \
				"not support '--pretend'.\n") % myaction)
			return 1

	if "sync" == myaction:
		return action_sync(settings, trees, mtimedb, myopts, myaction)
	elif "metadata" == myaction:
		action_metadata(settings, portdb, myopts)
	elif myaction=="regen":
		validate_ebuild_environment(trees)
		return action_regen(settings, portdb, myopts.get("--jobs"),
			myopts.get("--load-average"))
	# HELP action
	elif "config"==myaction:
		validate_ebuild_environment(trees)
		action_config(settings, trees, myopts, myfiles)

	# SEARCH action
	elif "search"==myaction:
		validate_ebuild_environment(trees)
		action_search(trees[settings["ROOT"]]["root_config"],
			myopts, myfiles, spinner)
	elif myaction in ("clean", "unmerge") or \
		(myaction == "prune" and "--nodeps" in myopts):
		validate_ebuild_environment(trees)

		# Ensure atoms are valid before calling unmerge().
		# For backward compat, leading '=' is not required.
		for x in myfiles:
			if is_valid_package_atom(x) or \
				is_valid_package_atom("=" + x):
				continue
			msg = []
			msg.append("'%s' is not a valid package atom." % (x,))
			msg.append("Please check ebuild(5) for full details.")
			writemsg_level("".join("!!! %s\n" % line for line in msg),
				level=logging.ERROR, noiselevel=-1)
			return 1

		# When given a list of atoms, unmerge
		# them in the order given.
		ordered = myaction == "unmerge"
		if 1 == unmerge(root_config, myopts, myaction, myfiles,
			mtimedb["ldpath"], ordered=ordered):
			if not (buildpkgonly or fetchonly or pretend):
				post_emerge(root_config, myopts, mtimedb, os.EX_OK)

	elif myaction in ("depclean", "info", "prune"):

		# Ensure atoms are valid before calling unmerge().
		vardb = trees[settings["ROOT"]]["vartree"].dbapi
		valid_atoms = []
		for x in myfiles:
			if is_valid_package_atom(x):
				try:
					valid_atoms.append(
						portage.dep_expand(x, mydb=vardb, settings=settings))
				except portage.exception.AmbiguousPackageName, e:
					msg = "The short ebuild name \"" + x + \
						"\" is ambiguous.  Please specify " + \
						"one of the following " + \
						"fully-qualified ebuild names instead:"
					for line in textwrap.wrap(msg, 70):
						writemsg_level("!!! %s\n" % (line,),
							level=logging.ERROR, noiselevel=-1)
					for i in e[0]:
						writemsg_level("    %s\n" % colorize("INFORM", i),
							level=logging.ERROR, noiselevel=-1)
					writemsg_level("\n", level=logging.ERROR, noiselevel=-1)
					return 1
				continue
			msg = []
			msg.append("'%s' is not a valid package atom." % (x,))
			msg.append("Please check ebuild(5) for full details.")
			writemsg_level("".join("!!! %s\n" % line for line in msg),
				level=logging.ERROR, noiselevel=-1)
			return 1

		if myaction == "info":
			return action_info(settings, trees, myopts, valid_atoms)

		validate_ebuild_environment(trees)
		action_depclean(settings, trees, mtimedb["ldpath"],
			myopts, myaction, valid_atoms, spinner)
		if not (buildpkgonly or fetchonly or pretend):
			post_emerge(root_config, myopts, mtimedb, os.EX_OK)
	# "update", "system", or just process files:
	else:
		validate_ebuild_environment(trees)
		if "--pretend" not in myopts:
			display_news_notification(root_config, myopts)
		retval = action_build(settings, trees, mtimedb,
			myopts, myaction, myfiles, spinner)
		root_config = trees[settings["ROOT"]]["root_config"]
		post_emerge(root_config, myopts, mtimedb, retval)

		return retval