# Copyright 2017 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2

# @ECLASS: meson.eclass
# @MAINTAINER:
# William Hubbs <williamh@gentoo.org>
# Mike Gilbert <floppym@gentoo.org>
# @BLURB: common ebuild functions for meson-based packages
# @DESCRIPTION:
# This eclass contains the default phase functions for packages which
# use the meson build system.
#
# @EXAMPLE:
# Typical ebuild using meson.eclass:
#
# @CODE
# EAPI=6
#
# inherit meson
#
# ...
#
# src_configure() {
# 	local emesonargs=(
# 		-Dqt4=$(usex qt4 true false)
# 		-Dthreads=$(usex threads true false)
# 		-Dtiff=$(usex tiff true false)
# 	)
# 	meson_src_configure
# }
#
# ...
#
# @CODE

case ${EAPI:-0} in
	6) ;;
	*) die "EAPI=${EAPI} is not supported" ;;
esac

if [[ -z ${_MESON_ECLASS} ]]; then

inherit ninja-utils toolchain-funcs

fi

EXPORT_FUNCTIONS src_configure src_compile src_test src_install

if [[ -z ${_MESON_ECLASS} ]]; then
_MESON_ECLASS=1

DEPEND=">=dev-util/meson-0.40.0
	>=dev-util/ninja-1.7.2"

# @ECLASS-VARIABLE: BUILD_DIR
# @DEFAULT_UNSET
# @DESCRIPTION:
# Build directory, location where all generated files should be placed.
# If this isn't set, it defaults to ${WORKDIR}/${P}-build.

# @ECLASS-VARIABLE: EMESON_SOURCE
# @DEFAULT_UNSET
# @DESCRIPTION:
# The location of the source files for the project; this is the source
# directory to pass to meson.
# If this isn't set, it defaults to ${S}

# @VARIABLE: emesonargs
# @DEFAULT_UNSET
# @DESCRIPTION:
# Optional meson arguments as Bash array; this should be defined before
# calling meson_src_configure.

# @FUNCTION: _meson_create_cross_file
# @INTERNAL
# @DESCRIPTION:
# Creates a cross file. meson uses this to define settings for
# cross-compilers. This function is called from meson_src_configure.
_meson_create_cross_file() {
	# Reference: http://mesonbuild.com/Cross-compilation.html

	# system roughly corresponds to uname -s (lowercase)
	local system=unknown
	case ${CHOST} in
		*-aix*)     system=aix ;;
		*-cygwin*)  system=cygwin ;;
		*-darwin*)  system=darwin ;;
		*-freebsd*) system=freebsd ;;
		*-linux*)   system=linux ;;
		*-solaris*) system=sunos ;;
	esac

	local cpu_family=$(tc-arch)
	case ${cpu_family} in
		amd64) cpu_family=x86_64 ;;
		arm64) cpu_family=aarch64 ;;
	esac

	# This may require adjustment based on CFLAGS
	local cpu=${CHOST%%-*}

	cat > "${T}/meson.${CHOST}" <<-EOF
	[binaries]
	ar = '${AR}'
	c = '${CC}'
	cpp = '${CXX}'
	strip = '${STRIP}'

	[host_machine]
	system = '${system}'
	cpu_family = '${cpu_family}'
	cpu = '${cpu}'
	endian = '$(tc-endian)'
	EOF
}

# @FUNCTION: meson_src_configure
# @DESCRIPTION:
# This is the meson_src_configure function.
meson_src_configure() {
	debug-print-function ${FUNCNAME} "$@"

	# Common args
	local mesonargs=(
		--buildtype plain
		--libdir "$(get_libdir)"
		--localstatedir "${EPREFIX}/var/lib"
		--prefix "${EPREFIX}/usr"
		--sysconfdir "${EPREFIX}/etc"
		--wrap-mode nodownload
		)

	# Both meson(1) and _meson_create_cross_file need these
	local -x AR=$(tc-getAR)
	local -x CC=$(tc-getCC)
	local -x CXX=$(tc-getCXX)
	local -x STRIP=$(tc-getSTRIP)

	if tc-is-cross-compiler; then
		_meson_create_cross_file || die "unable to write meson cross file"
		mesonargs+=(
			--cross-file "${T}/meson.${CHOST}"
		)
		# In cross mode, meson uses these as the native/build programs
		AR=$(tc-getBUILD_AR)
		CC=$(tc-getBUILD_CC)
		CXX=$(tc-getBUILD_CXX)
		STRIP=$(tc-getBUILD_STRIP)
	fi

	# Append additional arguments from ebuild
	mesonargs+=("${emesonargs[@]}")

	BUILD_DIR="${BUILD_DIR:-${WORKDIR}/${P}-build}"
	set -- meson "${mesonargs[@]}" "$@" \
		"${EMESON_SOURCE:-${S}}" "${BUILD_DIR}"
	echo "$@"
	"$@" || die
}

# @FUNCTION: meson_src_compile
# @DESCRIPTION:
# This is the meson_src_compile function.
meson_src_compile() {
	debug-print-function ${FUNCNAME} "$@"

	eninja -C "${BUILD_DIR}"
}

# @FUNCTION: meson_src_test
# @DESCRIPTION:
# This is the meson_src_test function.
meson_src_test() {
	debug-print-function ${FUNCNAME} "$@"

	eninja -C "${BUILD_DIR}" test
}

# @FUNCTION: meson_src_install
# @DESCRIPTION:
# This is the meson_src_install function.
meson_src_install() {
	debug-print-function ${FUNCNAME} "$@"

	DESTDIR="${D}" eninja -C "${BUILD_DIR}" install
	einstalldocs
}

fi