[gentoo-dev] [PATCH 3/3] Support out-of-source builds.

[Michał Górny]

---
 gx86/eclass/distutils-r1.eclass | 50 ++++++++++++++++++++++++++++++++++++-----
 1 file changed, 45 insertions(+), 5 deletions(-)

diff --git a/gx86/eclass/distutils-r1.eclass b/gx86/eclass/distutils-r1.eclass
index 6bec5bb..cce47a7 100644
--- a/gx86/eclass/distutils-r1.eclass
+++ b/gx86/eclass/distutils-r1.eclass
@@ -105,6 +105,22 @@ DEPEND=${PYTHON_DEPS}
 # HTML_DOCS=( doc/html/ )
 # @CODE
 
+# @ECLASS-VARIABLE: DISTUTILS_IN_SOURCE_BUILD
+# @DEFAULT_UNSET
+# @DESCRIPTION:
+# If set to a non-null value, in-source builds will be enabled.
+# If unset, the default is to use in-source builds when python_prepare()
+# is declared, and out-of-source builds otherwise.
+#
+# If in-source builds are used, the eclass will create a copy of package
+# sources for each Python implementation in python_prepare_all(),
+# and work on that copy afterwards.
+#
+# If out-of-source builds are used, the eclass will instead work
+# on the sources directly, prepending setup.py arguments with
+# 'build --build-base ${BUILD_DIR}' to enforce keeping & using built
+# files in the specific root.
+
 # @ECLASS-VARIABLE: myesetuppyargs
 # @DEFAULT_UNSET
 # @DESCRIPTION:
@@ -130,7 +146,16 @@ DEPEND=${PYTHON_DEPS}
 esetuppy() {
 	debug-print-function ${FUNCNAME} "${@}"
 
-	set -- "${PYTHON:-python}" setup.py \
+	local args=()
+	if [[ ! ${DISTUTILS_IN_SOURCE_BUILD} ]]; then
+		if [[ ! ${BUILD_DIR} ]]; then
+			die 'Out-of-source build requested, yet BUILD_DIR unset.'
+		fi
+
+		args+=( build --build-base "${BUILD_DIR}" )
+	fi
+
+	set -- "${PYTHON:-python}" setup.py "${args[@]}" \
 		"${myesetuppyargs[@]}" "${@}"
 
 	echo "${@}" >&2
@@ -152,8 +177,17 @@ distutils-r1_python_prepare_all() {
 
 	epatch_user
 
-	# create source copies for each implementation
-	python_copy_sources
+	# by default, use in-source build if python_prepare() is used
+	if [[ ! ${DISTUTILS_IN_SOURCE_BUILD+1} ]]; then
+		if declare -f python_prepare >/dev/null; then
+			DISTUTILS_IN_SOURCE_BUILD=1
+		fi
+	fi
+
+	if [[ ${DISTUTILS_IN_SOURCE_BUILD} ]]; then
+		# create source copies for each implementation
+		python_copy_sources
+	fi
 }
 
 # @FUNCTION: distutils-r1_python_prepare
@@ -297,9 +331,15 @@ distutils-r1_python_install_all() {
 distutils-r1_run_phase() {
 	debug-print-function ${FUNCNAME} "${@}"
 
-	pushd "${BUILD_DIR}" &>/dev/null || die
+	if [[ ${DISTUTILS_IN_SOURCE_BUILD} ]]; then
+		pushd "${BUILD_DIR}" &>/dev/null || die
+	fi
+
 	"${@}" || die "${1} failed."
-	popd &>/dev/null || die
+
+	if [[ ${DISTUTILS_IN_SOURCE_BUILD} ]]; then
+		popd &>/dev/null || die
+	fi
 }
 
 distutils-r1_src_prepare() {
-- 
1.7.12.4