[gentoo-dev] [PATCH 1/8] llvm.org.eclass: New eclass to help maintaining LLVM

[Michał Górny]

llvm.org eclass is meant to provide helper routines for maintaining
LLVM packages.  It takes care of covering the differences between
release, prerelease and git ebuilds in a unified API.  This will make
maintenance much easier.

Initially, the eclass takes care of fetching and unpacking the archives.
Later on, I will work on moving some more common stuff there.

Signed-off-by: Michał Górny <mgorny@g.o>
---
 eclass/llvm.org.eclass | 198 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 198 insertions(+)
 create mode 100644 eclass/llvm.org.eclass

// I'm following this up with a few example updates to ebuilds.  This
// patchset neither covers all ebuilds nor is final.

diff --git a/eclass/llvm.org.eclass b/eclass/llvm.org.eclass
new file mode 100644
index 000000000000..5a704c1d9805
--- /dev/null
+++ b/eclass/llvm.org.eclass
@@ -0,0 +1,198 @@
+# Copyright 2019 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+# @ECLASS: llvm.org.eclass
+# @MAINTAINER:
+# Michał Górny <mgorny@g.o>
+# @AUTHOR:
+# Michał Górny <mgorny@g.o>
+# @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=10
+
+# @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?!"
+
+
+# == 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.
+
+
+# == global scope logic ==
+
+# @FUNCTION: _llvm.org_get_archives
+# @USAGE: <components>
+# @INTERNAL
+# @DESCRIPTION:
+# Set 'archives' array to list of unique archive filenames
+# for components passed as parameters.
+_llvm.org_get_archives() {
+	local c
+	archives=()
+
+	for c; do
+		local cn=${c%%/*}
+		case ${cn} in
+			clang) cn=cfe;;
+		esac
+
+		local a=${cn}-${PV}.src.tar.xz
+		has "${a}" "${archives[@]}" || archives+=( "${a}" )
+	done
+}
+
+# @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 [[ ${_LLVM_SOURCE_TYPE} == tar ]]; then
+		local a archives=()
+		_llvm.org_get_archives "${LLVM_COMPONENTS[@]}"
+		for a in "${archives[@]}"; do
+			SRC_URI+="
+				https://releases.llvm.org/${PV}/${a}"
+		done
+	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 )"
+
+		if [[ ${_LLVM_SOURCE_TYPE} == tar ]]; then
+			SRC_URI+="
+				test? ("
+
+			_llvm.org_get_archives "${LLVM_TEST_COMPONENTS[@]}"
+			for a in "${archives[@]}"; do
+				SRC_URI+="
+					https://releases.llvm.org/${PV}/${a}"
+			done
+
+			SRC_URI+="
+				)"
+		fi
+	fi
+
+	_LLVM_ORG_SET_GLOBALS_CALLED=1
+}
+
+
+# == phase functions ==
+
+EXPORT_FUNCTIONS src_unpack
+
+# @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[@]}"
+	else
+		local c archives
+		# TODO: optimize this
+		for c in "${components[@]}"; do
+			local top_dir=${c%%/*}
+			_llvm.org_get_archives "${c}"
+			local sub_path=${archives[0]%.tar.xz}
+			[[ ${c} == */* ]] && sub_path+=/${c#*/}
+
+			ebegin "Unpacking ${sub_path} from ${archives[0]}"
+			mkdir -p "${top_dir}" || die
+			tar -C "${top_dir}" -x -J -o --strip-components 1 \
+				-f "${DISTDIR}/${archives[0]}" "${sub_path}" || die
+			eend
+		done
+	fi
+}
-- 
2.23.0