[LTP] [RFC PATCH 1/3] Makefile: Add C header with generated LTP version

[Cyril Hrubis]

Hi!
> obviously this is wrong, because $(top_srcdir)/Version (ltp-version.h
> dependency) is not specified in the top level Makefile (only Version is
> there). But I'm not sure if it should be changed to
> $(top_srcdir)/Version.
> 
> I suppose ltp-version.h should be in include/

Not reall, as long as it's used only in the library it can stay in the
lib/

> , but here I'm completely lost with dependencies under lib/. My goal
> is to type make in lib/ and make sure the header is generated
> (dependencies correctly resolved).

There is another problem as well, currently the Version file is
generated at the end of the LTP build, that means if you do a git pull
and make it's not updated until the build has finished.

Also we will have to rebuild tst_test.c each time Version file has been
rewritten, which actually happens each time make is build in the top
level directory, which would cause useless rebuilds.

The best I could came up with:

---
 lib/.gitignore     |  2 ++
 lib/Makefile       | 13 +++++++++++++
 lib/gen_version.sh | 16 ++++++++++++++++
 3 files changed, 31 insertions(+)
 create mode 100644 lib/.gitignore
 create mode 100755 lib/gen_version.sh

diff --git a/lib/.gitignore b/lib/.gitignore
new file mode 100644
index 000000000..178867a94
--- /dev/null
+++ b/lib/.gitignore
@@ -0,0 +1,2 @@
+ltp-version.h
+cached-version
diff --git a/lib/Makefile b/lib/Makefile
index 9b9906f25..371119ede 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -20,6 +20,19 @@ pc_file			:= $(DESTDIR)/$(datarootdir)/pkgconfig/ltp.pc
 
 INSTALL_TARGETS		:= $(pc_file)
 
+tst_test.o: ltp-version.h
+
+ltp-version.h: gen_version
+
+MAKE_TARGETS+=gen_version
+
+.PHONY: gen_version
+gen_version:
+	@echo GEN ltp-version.h
+	@./gen_version.sh
+
+CLEAN_TARGETS+=ltp-version.h cached-version
+
 $(pc_file):
 	test -d "$(@D)" || mkdir -p "$(@D)"
 	install -m $(INSTALL_MODE) "$(builddir)/$(@F)" "$@"
diff --git a/lib/gen_version.sh b/lib/gen_version.sh
new file mode 100755
index 000000000..7ecfb9077
--- /dev/null
+++ b/lib/gen_version.sh
@@ -0,0 +1,16 @@
+#!/bin/sh
+
+touch cached-version;
+
+if git describe >/dev/null 2>&1; then
+	VERSION=`git describe`
+else
+	VERSION=`cat $(top_srcdir)/VERSION`
+fi
+
+CACHED_VERSION=`cat cached-version`
+
+if [ "$CACHED_VERSION" != "$VERSION" ]; then
+	echo "$VERSION" > cached-version
+	echo "#define LTP_VERSION \"$VERSION\"" > ltp-version.h
+fi

-- 
Cyril Hrubis
chrubis@suse.cz