scons-utils.eclass: sync with upstream Gentoo

Upstream Gentoo has added a dedicated eclass for working with scons
projects.  Nothing in the tree uses this yet, but some packages down
the line will.

BUG=None
TEST=None

Change-Id: Ibdfe1b7386e4cdbecc7c1cdc981092cda4993332
Reviewed-on: https://gerrit.chromium.org/gerrit/11994
Reviewed-by: David James <davidjames@chromium.org>
Commit-Ready: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>

sdk_container/src/third_party/portage-stable/eclass/scons-utils.eclass

@@ -0,0 +1,235 @@
+# Copyright 1999-2011 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+# $Header: /var/cvsroot/gentoo-x86/eclass/scons-utils.eclass,v 1.9 2011/11/18 20:51:10 mgorny Exp $
+
+# @ECLASS: scons-utils.eclass
+# @MAINTAINER:
+# mgorny@gentoo.org
+# @BLURB: helper functions to deal with SCons buildsystem
+# @DESCRIPTION:
+# This eclass provides a set of function to help developers sanely call
+# dev-util/scons and pass parameters to it.
+# @EXAMPLE:
+#
+# @CODE
+# inherit scons-utils toolchain-funcs
+#
+# EAPI=4
+#
+# src_configure() {
+# 	myesconsargs=(
+# 		CC="$(tc-getCC)"
+# 		$(use_scons nls ENABLE_NLS)
+# 	)
+# }
+#
+# src_compile() {
+# 	escons
+# }
+#
+# src_install() {
+# 	# note: this can be DESTDIR, INSTALL_ROOT, ... depending on package
+# 	escons DESTDIR="${D}" install
+# }
+# @CODE
+
+# -- public variables --
+
+# @ECLASS-VARIABLE: SCONS_MIN_VERSION
+# @DEFAULT_UNSET
+# @DESCRIPTION:
+# The minimal version of SCons required for the build to work.
+
+# @VARIABLE: myesconsargs
+# @DEFAULT_UNSET
+# @DESCRIPTION:
+# List of package-specific options to pass to all SCons calls. Supposed to be
+# set in src_configure().
+
+# @ECLASS-VARIABLE: SCONSOPTS
+# @DEFAULT_UNSET
+# @DESCRIPTION:
+# The default set of options to pass to scons. Similar to MAKEOPTS,
+# supposed to be set in make.conf. If unset, escons() will use cleaned
+# up MAKEOPTS instead.
+
+# @ECLASS-VARIABLE: EXTRA_ESCONS
+# @DEFAULT_UNSET
+# @DESCRIPTION:
+# The additional parameters to pass to SCons whenever escons() is used.
+# Much like EXTRA_EMAKE, this is not supposed to be used in make.conf
+# and not in ebuilds!
+
+# @ECLASS-VARIABLE: USE_SCONS_TRUE
+# @DESCRIPTION:
+# The default value for truth in scons-use() (1 by default).
+: ${USE_SCONS_TRUE:=1}
+
+# @ECLASS-VARIABLE: USE_SCONS_FALSE
+# @DESCRIPTION:
+# The default value for false in scons-use() (0 by default).
+: ${USE_SCONS_FALSE:=0}
+
+# -- EAPI support check --
+
+case ${EAPI:-0} in
+	0|1|2|3|4) ;;
+	*) die "EAPI ${EAPI} unsupported."
+esac
+
+# -- ebuild variables setup --
+
+if [[ -n ${SCONS_MIN_VERSION} ]]; then
+	DEPEND=">=dev-util/scons-${SCONS_MIN_VERSION}"
+else
+	DEPEND="dev-util/scons"
+fi
+
+# -- public functions --
+
+# @FUNCTION: escons
+# @USAGE: [scons-arg] ...
+# @DESCRIPTION:
+# Call scons, passing the supplied arguments, ${myesconsargs[@]},
+# filtered ${MAKEOPTS}, ${EXTRA_ESCONS}. Similar to emake. Like emake,
+# this function does die on failure in EAPI 4 (unless called nonfatal).
+escons() {
+	local ret
+
+	debug-print-function ${FUNCNAME} "${@}"
+
+	# if SCONSOPTS are _unset_, use cleaned MAKEOPTS
+	set -- scons ${SCONSOPTS-$(scons_clean_makeopts)} ${EXTRA_ESCONS} \
+		"${myesconsargs[@]}" "${@}"
+	echo "${@}" >&2
+	"${@}"
+	ret=${?}
+
+	[[ ${ret} -ne 0 && ${EAPI:-0} -ge 4 ]] && die "escons failed."
+	return ${ret}
+}
+
+# @FUNCTION: scons_clean_makeopts
+# @USAGE: [makeflags] [...]
+# @DESCRIPTION:
+# Strip the supplied makeflags (or ${MAKEOPTS} if called without
+# an argument) of options not supported by SCons and make sure --jobs
+# gets an argument. Output the resulting flag list (suitable
+# for an assignment to SCONSOPTS).
+scons_clean_makeopts() {
+	local new_makeopts
+
+	debug-print-function ${FUNCNAME} "${@}"
+
+	if [[ ${#} -eq 0 ]]; then
+		debug-print "Using MAKEOPTS: [${MAKEOPTS}]"
+		set -- ${MAKEOPTS}
+	else
+		# unquote if necessary
+		set -- ${*}
+	fi
+
+	# empty MAKEOPTS give out empty SCONSOPTS
+	# thus, we do need to worry about the initial setup
+	if [[ ${*} = ${_SCONS_CACHE_MAKEOPTS} ]]; then
+		set -- ${_SCONS_CACHE_SCONSOPTS}
+		debug-print "Cache hit: [${*}]"
+		echo ${*}
+		return
+	fi
+	export _SCONS_CACHE_MAKEOPTS=${*}
+
+	while [[ ${#} -gt 0 ]]; do
+		case ${1} in
+			# clean, simple to check -- we like that
+			--jobs=*|--keep-going)
+				new_makeopts=${new_makeopts+${new_makeopts} }${1}
+				;;
+			# need to take a look at the next arg and guess
+			--jobs)
+				if [[ ${#} -gt 1 && ${2} =~ ^[0-9]+$ ]]; then
+					new_makeopts="${new_makeopts+${new_makeopts} }${1} ${2}"
+					shift
+				else
+					# no value means no limit, let's pass a random int
+					new_makeopts=${new_makeopts+${new_makeopts} }${1}=5
+				fi
+				;;
+			# strip other long options
+			--*)
+				;;
+			# short option hell
+			-*)
+				local str new_optstr
+				new_optstr=
+				str=${1#-}
+
+				while [[ -n ${str} ]]; do
+					case ${str} in
+						k*)
+							new_optstr=${new_optstr}k
+							;;
+						# -j needs to come last
+						j)
+							if [[ ${#} -gt 1 && ${2} =~ ^[0-9]+$ ]]; then
+								new_optstr="${new_optstr}j ${2}"
+								shift
+							else
+								new_optstr="${new_optstr}j 5"
+							fi
+							;;
+						# otherwise, everything after -j is treated as an arg
+						j*)
+							new_optstr=${new_optstr}${str}
+							break
+							;;
+					esac
+					str=${str#?}
+				done
+
+				if [[ -n ${new_optstr} ]]; then
+					new_makeopts=${new_makeopts+${new_makeopts} }-${new_optstr}
+				fi
+				;;
+		esac
+		shift
+	done
+
+	set -- ${new_makeopts}
+	export _SCONS_CACHE_SCONSOPTS=${*}
+	debug-print "New SCONSOPTS: [${*}]"
+	echo ${*}
+}
+
+# @FUNCTION: use_scons
+# @USAGE: <use-flag> [var-name] [var-opt-true] [var-opt-false]
+# @DESCRIPTION:
+# Output a SCons parameter with value depending on the USE flag state.
+# If the USE flag is set, output <var-name>=<var-opt-true>; otherwise
+# <var-name>=<var-opt-false>.
+#
+# If <var-name> is omitted, <use-flag> will be used instead. However,
+# if <use-flag> starts with an exclamation mark (!flag), 'no' will be
+# prepended to the name (e.g. noflag).
+#
+# If <var-opt-true> and/or <var-opt-false> are omitted,
+# ${USE_SCONS_TRUE} and/or ${USE_SCONS_FALSE} will be used instead.
+use_scons() {
+	local flag=${1}
+	local varname=${2:-${flag/\!/no}}
+	local vartrue=${3:-${USE_SCONS_TRUE}}
+	local varfalse=${4:-${USE_SCONS_FALSE}}
+
+	debug-print-function ${FUNCNAME} "${@}"
+
+	if [[ ${#} -eq 0 ]]; then
+		eerror "Usage: scons-use <use-flag> [var-name] [var-opt-true] [var-opt-false]"
+		die 'scons-use(): not enough arguments'
+	fi
+
+	if use "${flag}"; then
+		echo "${varname}=${vartrue}"
+	else
+		echo "${varname}=${varfalse}"
+	fi
+}