build: Convert git_sha1_gen script to Python.

Python is the scripting language we've been using for scripts that need
to run across all supported platforms.

Shell is *not* a portable language for scripts.

Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>

Makefile.am

@@ -53,7 +53,7 @@ EXTRA_DIST = \
 	common.py \
 	docs \
 	doxygen \
-	bin/git_sha1_gen.sh \
+	bin/git_sha1_gen.py \
 	scons \
 	SConstruct
 

bin/git_sha1_gen.py

@@ -0,0 +1,20 @@
+#!/usr/bin/env python
+
+import os.path
+import subprocess
+import sys
+
+git_dir = os.path.join(os.path.dirname(sys.argv[0]), '..', '.git')
+try:
+    git_sha1 = subprocess.check_output([
+        'git',
+        '--git-dir=' + git_dir,
+        'rev-parse',
+        '--short=10',
+        'HEAD',
+    ], stderr=open(os.devnull, 'w'))
+except subprocess.CalledProcessError as e:
+    # don't print anything if git fails
+    pass
+else:
+    sys.stdout.write('#define MESA_GIT_SHA1 "git-%s"\n' % git_sha1.rstrip())

bin/git_sha1_gen.sh

@@ -1,12 +0,0 @@
-#!/bin/sh
-
-# run git from the sources directory
-cd "$(dirname "$0")"
-
-# don't print anything if git fails
-if ! git_sha1=$(git --git-dir=../.git rev-parse --short=10 HEAD 2>/dev/null)
-then
-  exit
-fi
-
-printf '#define MESA_GIT_SHA1 "git-%s"\n' "$git_sha1"

src/Makefile.am

@@ -21,7 +21,7 @@
 
 .PHONY: git_sha1.h.tmp
 git_sha1.h.tmp:
-	@sh $(top_srcdir)/bin/git_sha1_gen.sh > $@
+	@python $(top_srcdir)/bin/git_sha1_gen.py > $@
 
 git_sha1.h: git_sha1.h.tmp
 	@echo "updating git_sha1.h"

src/SConscript

@@ -1,6 +1,7 @@
 import filecmp
 import os
 import subprocess
+from sys import executable as python_cmd
 
 Import('*')
 
@@ -25,7 +26,7 @@ def write_git_sha1_h_file(filename):
 
     tempfile = "git_sha1.h.tmp"
     with open(tempfile, "w") as f:
-        args = [ 'sh', Dir('#').abspath + '/bin/git_sha1_gen.sh' ]
+        args = [ python_cmd, Dir('#').abspath + '/bin/git_sha1_gen.py' ]
         try:
             subprocess.Popen(args, stdout=f).wait()
         except:

src/mesa/Android.libmesa_git_sha1.mk

@@ -46,7 +46,7 @@ LOCAL_GENERATED_SOURCES += $(addprefix $(intermediates)/, git_sha1.h)
 $(intermediates)/git_sha1.h: $(wildcard $(MESA_TOP)/.git/logs/HEAD)
 	@mkdir -p $(dir $@)
 	@echo "GIT-SHA1: $(PRIVATE_MODULE) <= git"
-	$(hide) sh $(MESA_TOP)/bin/git_sha1_gen.sh > $@
+	$(hide) python $(MESA_TOP)/bin/git_sha1_gen.py > $@
 
 LOCAL_EXPORT_C_INCLUDE_DIRS := $(intermediates)