# Copyright 2019-2021 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2

# @ECLASS: llvm.org.eclass
# @MAINTAINER:
# Michał Górny <mgorny@gentoo.org>
# @AUTHOR:
# Michał Górny <mgorny@gentoo.org>
# @BLURB: Common bits for fetching & unpacking llvm.org projects
# @DESCRIPTION:
# The llvm.org eclass provides common code to fetch and unpack parts
# of the llvm.org project tree.  It takes care of handling both git
# checkouts and source tarballs, making it possible to unify the code
# of live and release ebuilds and effectively reduce the work needed
# to package new releases/RCs/branches.
#
# In order to use this eclass, the ebuild needs to declare
# LLVM_COMPONENTS and then call llvm.org_set_globals.  If tests require
# additional components, they need to be listed in LLVM_TEST_COMPONENTS.
# The eclass exports an implementation of src_unpack() phase.
#
# Example:
# @CODE
# inherit llvm.org
#
# LLVM_COMPONENTS=( lld )
# LLVM_TEST_COMPONENTS=( llvm/utils/lit )
# llvm.org_set_globals
# @CODE

case "${EAPI:-0}" in
	7)
		;;
	*)
		die "Unsupported EAPI=${EAPI} for ${ECLASS}"
		;;
esac


# == internal control bits ==

# @ECLASS-VARIABLE: _LLVM_MASTER_MAJOR
# @INTERNAL
# @DESCRIPTION:
# The major version of current LLVM trunk.  Used to determine
# the correct branch to use.
_LLVM_MASTER_MAJOR=13

# @ECLASS-VARIABLE: _LLVM_SOURCE_TYPE
# @INTERNAL
# @DESCRIPTION:
# Source type to use: 'git' or 'tar'.
if [[ -z ${_LLVM_SOURCE_TYPE+1} ]]; then
	if [[ ${PV} == *.9999 ]]; then
		_LLVM_SOURCE_TYPE=git
	else
		_LLVM_SOURCE_TYPE=tar
	fi
fi

[[ ${_LLVM_SOURCE_TYPE} == git ]] && inherit git-r3

[[ ${PV} == ${_LLVM_MASTER_MAJOR}.* && ${_LLVM_SOURCE_TYPE} == tar ]] &&
	die "${ECLASS}: Release ebuild for master branch?!"

inherit multiprocessing


# == control variables ==

# @ECLASS-VARIABLE: LLVM_COMPONENTS
# @REQUIRED
# @DESCRIPTION:
# List of components needed unconditionally.  Specified as bash array
# with paths relative to llvm-project git.  Automatically translated
# for tarball releases.
#
# The first path specified is used to construct default S.

# @ECLASS-VARIABLE: LLVM_TEST_COMPONENTS
# @DEFAULT_UNSET
# @DESCRIPTION:
# List of additional components needed for tests.

# @ECLASS-VARIABLE: LLVM_MANPAGES
# @DEFAULT_UNSET
# @DESCRIPTION:
# Set to 'build', include the dependency on dev-python/sphinx to build
# the manpages.  If set to 'pregenerated', fetch and install
# pregenerated manpages from the archive.

# @ECLASS-VARIABLE: LLVM_PATCHSET
# @DEFAULT_UNSET
# @DESCRIPTION:
# LLVM patchset version.  No patchset is used if unset.


# == global scope logic ==

# @FUNCTION: llvm.org_set_globals
# @DESCRIPTION:
# Set global variables.  This must be called after setting LLVM_*
# variables used by the eclass.
llvm.org_set_globals() {
	if [[ $(declare -p LLVM_COMPONENTS) != "declare -a"* ]]; then
		die 'LLVM_COMPONENTS must be an array.'
	fi
	if declare -p LLVM_TEST_COMPONENTS &>/dev/null; then
		if [[ $(declare -p LLVM_TEST_COMPONENTS) != "declare -a"* ]]; then
			die 'LLVM_TEST_COMPONENTS must be an array.'
		fi
	fi

	if [[ ${_LLVM_SOURCE_TYPE} == git ]]; then
		EGIT_REPO_URI="https://github.com/llvm/llvm-project.git"

		[[ ${PV} != ${_LLVM_MASTER_MAJOR}.* ]] &&
			EGIT_BRANCH="release/${PV%%.*}.x"
	elif [[ ${_LLVM_SOURCE_TYPE} == tar ]]; then
		SRC_URI+="
			https://github.com/llvm/llvm-project/archive/llvmorg-${PV/_/-}.tar.gz"
	else
		die "Invalid _LLVM_SOURCE_TYPE: ${LLVM_SOURCE_TYPE}"
	fi

	S=${WORKDIR}/${LLVM_COMPONENTS[0]}

	if [[ -n ${LLVM_TEST_COMPONENTS+1} ]]; then
		IUSE+=" test"
		RESTRICT+=" !test? ( test )"
	fi

	case ${LLVM_MANPAGES:-__unset__} in
		__unset__)
			# no manpage support
			;;
		build)
			IUSE+=" doc"
			# NB: this is not always the correct dep but it does no harm
			BDEPEND+=" dev-python/sphinx"
			;;
		pregenerated)
			IUSE+=" doc"
			SRC_URI+="
				!doc? (
					https://dev.gentoo.org/~mgorny/dist/llvm/llvm-${PV}-manpages.tar.bz2
				)"
			;;
		*)
			die "Invalid LLVM_MANPAGES=${LLVM_MANPAGES}"
	esac

	if [[ -n ${LLVM_PATCHSET} ]]; then
		SRC_URI+="
			https://dev.gentoo.org/~mgorny/dist/llvm/llvm-gentoo-patchset-${LLVM_PATCHSET}.tar.xz"
	fi

	# === useful defaults for cmake-based packages ===

	# least intrusive of all
	CMAKE_BUILD_TYPE=RelWithDebInfo

	_LLVM_ORG_SET_GLOBALS_CALLED=1
}


# == phase functions ==

EXPORT_FUNCTIONS src_unpack
if ver_test -ge 10.0.1_rc; then
	EXPORT_FUNCTIONS src_prepare
fi

# @FUNCTION: llvm.org_src_unpack
# @DESCRIPTION:
# Unpack or checkout requested LLVM components.
llvm.org_src_unpack() {
	if [[ ! ${_LLVM_ORG_SET_GLOBALS_CALLED} ]]; then
		die "llvm.org_set_globals must be called in global scope"
	fi

	local components=( "${LLVM_COMPONENTS[@]}" )
	if [[ ${LLVM_TEST_COMPONENTS+1} ]] && use test; then
		components+=( "${LLVM_TEST_COMPONENTS[@]}" )
	fi

	if [[ ${_LLVM_SOURCE_TYPE} == git ]]; then
		git-r3_fetch
		git-r3_checkout '' . '' "${components[@]}"
		default_src_unpack
	else
		local archive=llvmorg-${PV/_/-}.tar.gz
		ebegin "Unpacking from ${archive}"
		tar -x -z -o --strip-components 1 \
			-f "${DISTDIR}/${archive}" \
			"${components[@]/#/llvm-project-${archive%.tar*}/}" || die
		eend ${?}

		# unpack all remaining distfiles
		local x
		for x in ${A}; do
			[[ ${x} != ${archive} ]] && unpack "${x}"
		done
	fi

	if [[ -n ${LLVM_PATCHSET} ]]; then
		# strip patches that don't match current components
		local IFS='|'
		grep -E -r -L "^Gentoo-Component:.*(${components[*]})" \
			"${WORKDIR}/llvm-gentoo-patchset-${LLVM_PATCHSET}" |
			xargs rm
		assert
	fi
}

# @FUNCTION: llvm.org_src_prepare
# @DESCRIPTION:
# Call appropriate src_prepare (cmake or default) depending on inherited
# eclasses.  Make sure that PATCHES and user patches are applied in top
# ${WORKDIR}, so that patches straight from llvm-project repository
# work correctly with -p1.
llvm.org_src_prepare() {
	if [[ -n ${LLVM_PATCHSET} ]]; then
		local PATCHES=(
			"${PATCHES[@]}"
			"${WORKDIR}/llvm-gentoo-patchset-${LLVM_PATCHSET}"
		)
	fi

	if declare -f cmake_src_prepare >/dev/null; then
		# cmake eclasses force ${S} for default_src_prepare
		# but use ${CMAKE_USE_DIR} for everything else
		CMAKE_USE_DIR=${S} \
		S=${WORKDIR} \
		cmake_src_prepare
	else
		pushd "${WORKDIR}" >/dev/null || die
		default_src_prepare
		popd >/dev/null || die
	fi
}


# == helper functions ==

# @ECLASS-VARIABLE: LIT_JOBS
# @USER_VARIABLE
# @DEFAULT_UNSET
# @DESCRIPTION:
# Number of test jobs to run simultaneously.  If unset, defaults
# to '-j' in MAKEOPTS.  If that is not found, default to nproc.

# @FUNCTION: get_lit_flags
# @DESCRIPTION:
# Get the standard recommended lit flags for running tests, in CMake
# list form (;-separated).
get_lit_flags() {
	echo "-vv;-j;${LIT_JOBS:-$(makeopts_jobs "${MAKEOPTS}" "$(get_nproc)")}"
}

# @FUNCTION: llvm_are_manpages_built
# @DESCRIPTION:
# Return true (0) if manpages are going to be built from source,
# false (1) if preinstalled manpages will be used.
llvm_are_manpages_built() {
	use doc || [[ ${LLVM_MANPAGES} == build ]]
}

# @FUNCTION: llvm_install_manpages
# @DESCRIPTION:
# Install pregenerated manpages if available.  No-op otherwise.
llvm_install_manpages() {
	# install pre-generated manpages
	if ! llvm_are_manpages_built; then
		# (doman does not support custom paths)
		insinto "/usr/lib/llvm/${SLOT}/share/man/man1"
		doins "${WORKDIR}/llvm-${PV}-manpages/${LLVM_COMPONENTS[0]}"/*.1
	fi
}