[gentoo-dev] [PATCH v2] libretro-core.eclass: An eclass to streamline the construction of Libretro core ebuilds

[Craig Andrews]

I'm proposing the addition of a new eclass,  libretro-core.eclass, which 
I'll use when adding a number of libretro ebuilds.

This version incorporates all the changes and suggestions posed so far.

The pull request which includes this eclass as well as a few ebuilds 
using it (with more to come) can be found at 
https://github.com/gentoo/gentoo/pull/9330

Thanks,
~Craig

---
  eclass/libretro-core.eclass | 197 ++++++++++++++++++++++++++++++++++++
  1 file changed, 197 insertions(+)
  create mode 100644 eclass/libretro-core.eclass

diff --git a/eclass/libretro-core.eclass b/eclass/libretro-core.eclass
new file mode 100644
index 000000000000..510f905111ce
--- /dev/null
+++ b/eclass/libretro-core.eclass
@@ -0,0 +1,197 @@
+# Copyright 1999-2018 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+
+# @ECLASS: libretro-core.eclass
+# @MAINTAINER:
+# candrews@g.o
+# @AUTHOR:
+# Cecil Curry <leycec@×××××.com>
+# Craig Andrews <candrews@g.o>
+# @BLURB: Simplify libretro core ebuilds
+# @DESCRIPTION:
+# The libretro eclass is designed to streamline the construction of
+# ebuilds for Libretro core ebuilds.
+#
+# Libretro cores can be found under https://github.com/libretro/
+#
+# They all use the same basic make based build system, are located
+# in the same github account, and do not release named or numbered
+# versions (so ebuild versions for git commits are keys).
+# This eclass covers those commonalities reducing much duplication
+# between the ebuilds.
+# @EXAMPLE:
+# @CODE
+# EAPI=7
+#
+# LIBRETRO_CORE_NAME="2048"
+# LIBRETRO_COMMIT_SHA="45655d3662e4cbcd8afb28e2ee3f5494a75888de"
+# KEYWORDS="~amd64 ~x86"
+# inherit libretro-core
+#
+# DESCRIPTION="Port of 2048 puzzle game to the libretro API"
+# LICENSE="Unlicense"
+# SLOT="0"
+# @CODE
+
+if [[ -z ${_LIBRETRO_CORE_ECLASS} ]]; then
+_LIBRETRO_CORE_ECLASS=1
+
+IUSE="debug"
+
+# @ECLASS-VARIABLE: LIBRETRO_CORE_NAME
+# @REQUIRED
+# @DESCRIPTION:
+# Name of this Libretro core. The libretro-core_src_install() phase 
function
+# will install the shared library 
"${S}/${LIBRETRO_CORE_NAME}_libretro.so" as a
+# Libretro core. Defaults to the name of the current package excluding 
the
+# "libretro-" prefix (e.g., "mgba" for the package "libretro-mgba").
+: ${LIBRETRO_CORE_NAME:=${PN#libretro-}}
+
+# @ECLASS-VARIABLE: LIBRETRO_COMMIT_SHA
+# @DESCRIPTION:
+# Commit SHA used for SRC_URI will die if not set in <9999 ebuilds.
+# Needs to be set before inherit.
+
+# @ECLASS-VARIABLE: LIBRETRO_REPO_NAME
+# @REQUIRED
+# @DESCRIPTION:
+# Contains the real repo name of the core formatted as 
"repouser/reponame".
+# Needs to be set before inherit. Otherwise defaults to 
"libretro/${PN}"
+: ${LIBRETRO_REPO_NAME:="libretro/libretro-${LIBRETRO_CORE_NAME}"}
+
+: ${HOMEPAGE:="https://github.com/${LIBRETRO_REPO_NAME}"}
+
+if [[ ${PV} == *9999 ]]; then
+	: ${EGIT_REPO_URI:="https://github.com/${LIBRETRO_REPO_NAME}.git"}
+	inherit git-r3
+else
+	[[ -z "${LIBRETRO_COMMIT_SHA}" ]] && die "LIBRETRO_COMMIT_SHA must be 
set before inherit."
+	S="${WORKDIR}/${LIBRETRO_REPO_NAME##*/}-${LIBRETRO_COMMIT_SHA}"
+	: 
${SRC_URI:="https://github.com/${LIBRETRO_REPO_NAME}/archive/${LIBRETRO_COMMIT_SHA}.tar.gz 
-> ${P}.tar.gz"}
+fi
+inherit flag-o-matic
+
+# @ECLASS-VARIABLE: LIBRETRO_CORE_LIB_FILE
+# @REQUIRED
+# @DESCRIPTION:
+# Absolute path of this Libretro core's shared library.
+: ${LIBRETRO_CORE_LIB_FILE:="${S}/${LIBRETRO_CORE_NAME}_libretro.so"}
+
+case "${EAPI:-0}" in
+	6|7)
+		EXPORT_FUNCTIONS src_unpack src_prepare src_compile src_install
+		;;
+	*)
+		die "EAPI=${EAPI} is not supported" ;;
+esac
+
+# @FUNCTION: libretro-core_src_unpack
+# @DESCRIPTION:
+# The libretro-core src_unpack function which is exported.
+#
+# This function retrieves the remote Libretro core info files.
+libretro-core_src_unpack() {
+	# If this is a live ebuild, retrieve this core's remote repository.
+	if [[ ${PV} == *9999 ]]; then
+		git-r3_src_unpack
+		# Add used commit SHA for version information, the above could also 
work.
+		LIBRETRO_COMMIT_SHA=$(git -C "${WORKDIR}/${P}" rev-parse HEAD)
+	# Else, unpack this core's local tarball.
+	else
+		default_src_unpack
+	fi
+}
+
+# @FUNCTION: libretro-core_src_prepare
+# @DESCRIPTION:
+# The libretro-core src_prepare function which is exported.
+#
+# This function prepares the source by making custom modifications.
+libretro-core_src_prepare() {
+	ebegin "Attempting to hack Makefiles to use custom cflags"
+	# Populate COMMIT for GIT_VERSION
+	CUSTOM_LIBRETRO_COMMIT_SHA="\" ${LIBRETRO_COMMIT_SHA:0:7}\""
+	local makefile
+	local flags_modified=0
+	local shopt_saved=$(shopt -p nullglob)
+	shopt -s nullglob
+	for makefile in "${S}"/[Mm]akefile* 
"${S}"/target-libretro/[Mm]akefile*; do
+		# * Convert CRLF to LF
+		# * Expand *FLAGS to prevent potential self-references
+		# * Where LDFLAGS directly define the link version
+		#   script append LDFLAGS and LIBS
+		# * Where SHARED is used to provide shared linking
+		#   flags ensure final link command includes LDFLAGS
+		#   and LIBS
+		# * Always use $(CFLAGS) when calling $(CC)
+		# * Add short-rev to Makefile
+		[[ -e "${makefile}" ]] && sed \
+			-e 's/\r$//g' \
+			-e "/flags.*=/s:-O[[:digit:]]:${CFLAGS}:g" \
+			-e "/CFLAGS.*=/s:-O[[:digit:]]:${CFLAGS}:g" \
+			-e "/.*,--version-script=.*/s:$: ${LDFLAGS} ${LIBS}:g" \
+			-e "/\$(CC)/s:\(\$(SHARED)\):\1 ${LDFLAGS} ${LIBS}:" \
+			-e 's:\(\$(CC)\):\1 \$(CFLAGS):g' \
+			-e 
"s/GIT_VERSION\s.=.*$/GIT_VERSION=${CUSTOM_LIBRETRO_COMMIT_SHA}/g" \
+			-i "${makefile}" || die "Failed to use custom cflags in ${makefile}"
+	done
+	${shopt_saved}
+	eend
+	export OPTFLAGS="${CFLAGS}"
+	default_src_prepare
+}
+
+# @VARIABLE: myemakeargs
+# @DEFAULT_UNSET
+# @DESCRIPTION:
+# Optional emake arguments as a bash array. Should be defined before 
calling
+# src_compile.
+# @CODE
+# src_compile() {
+#       local myemakeargs=(
+#		$(usex neon "HAVE_NEON=1" "")
+#	)
+#       libretro-core_src_configure
+# }
+# @CODE
+
+# @FUNCTION: libretro-core_src_compile
+# @DESCRIPTION:
+# The libretro-core src_compile function which is exported.
+#
+# This function compiles the shared library for this Libretro core.
+libretro-core_src_compile() {
+	# most (if not all) libretro makefiles use DEBUG=1
+	# to enable additional debug features.
+	emake CC=$(tc-getCC) CXX=$(tc-getCXX) \
+		$(usex debug "DEBUG=1" "") "${myemakeargs[@]}" \
+		$([[ -f makefile.libretro ]] && echo '-f makefile.libretro') \
+		$([[ -f Makefile.libretro ]] && echo '-f Makefile.libretro')
+}
+
+# @FUNCTION: libretro-core_src_install
+# @DESCRIPTION:
+# The libretro-core src_install function which is exported.
+#
+# This function installs the shared library for this Libretro core.
+libretro-core_src_install() {
+	# Absolute path of the directory containing Libretro shared libraries.
+	local LIBRETRO_LIB_DIR="/usr/$(get_libdir)/libretro"
+	# If this core's shared library exists, install that.
+	if [[ -f "${LIBRETRO_CORE_LIB_FILE}" ]]; then
+		insinto "${LIBRETRO_LIB_DIR}"
+		doexe "${LIBRETRO_CORE_LIB_FILE}"
+	else
+		# Basename of this library.
+		local lib_basename="${LIBRETRO_CORE_LIB_FILE##*/}"
+
+		# Absolute path to which this library was installed.
+		local lib_file_target="${ED}${LIBRETRO_LIB_DIR}/${lib_basename}"
+
+		# If this library was *NOT* installed, fail.
+		[[ -f "${lib_file_target}" ]] ||
+			die "Libretro core shared library \"${lib_file_target}\" not 
installed."
+	fi
+}
+
+fi # end _LIBRETRO_CORE_ECLASS guard
-- 
2.18.0