[LTP] [PATCH v3 2/4] doc/Makefile: Allow to create and use .venv

[Petr Vorel]

This is an optional target (not run by default).
If .venv exists, it's used in other targets.

This helps to use virtualenv for development, but avoid using it by
default (readthedoc uses container with virtualenv, creating it would be
waste of time).

Add 'distclean' target which removes also .venv/ directory.

Signed-off-by: Petr Vorel <pvorel@suse.cz>
---
Changes since v2:
* Add distclean in "doc/Makefile: Allow to create and use .venv"

 doc/Makefile | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/doc/Makefile b/doc/Makefile
index 3c5682ad00..3b8265d88e 100644
--- a/doc/Makefile
+++ b/doc/Makefile
@@ -5,15 +5,30 @@ top_srcdir		?= ..
 
 include $(top_srcdir)/include/mk/env_pre.mk
 
+PYTHON := python3
+VENV_DIR := .venv
+VENV_CMD := . $(VENV_DIR)/bin/activate
+RUN_VENV := if [ -d $(VENV_DIR) ]; then $(VENV_CMD); fi
+
+# install sphinx only if needed
+INSTALL_SPHINX := $(shell $(PYTHON) -c "import sphinx" 2>/dev/null && echo ":" || echo "pip install sphinx")
+
+$(VENV_DIR):
+	$(PYTHON) -m virtualenv $(VENV_DIR)
+	$(VENV_CMD) && pip install -r requirements.txt && $(INSTALL_SPHINX)
+
 ${abs_top_builddir}/metadata/ltp.json:
 	$(MAKE) -C ${abs_top_builddir}/metadata
 
 all: ${abs_top_builddir}/metadata/ltp.json
-	sphinx-build -b html . html
+	$(RUN_VENV); sphinx-build -b html . html
 
 spelling:
-	sphinx-build -b spelling -d build/doctree . build/spelling
+	$(RUN_VENV); sphinx-build -b spelling -d build/doctree . build/spelling
 
 clean:
 	rm -rf html/ build/ _static/syscalls.rst _static/tests.rst syscalls.tbl \
 		${abs_top_builddir}/metadata/ltp.json
+
+distclean: clean
+	rm -rf $(VENV_DIR)
-- 
2.47.2