bin/git_sha1_gen.py

   1 #!/usr/bin/env python
   2
   3 """
   4 Generate the contents of the git_sha1.h file.
   5 The output of this script goes to stdout.
   6 """
   7
   8
   9 import argparse
  10 import os
  11 import os.path
  12 import subprocess
  13 import sys
  14
  15
  16 def get_git_sha1():
  17     """Try to get the git SHA1 with git rev-parse."""
  18     git_dir = os.path.join(os.path.dirname(sys.argv[0]), '..', '.git')
  19     try:
  20         git_sha1 = subprocess.check_output([
  21             'git',
  22             '--git-dir=' + git_dir,
  23             'rev-parse',
  24             'HEAD',
  25         ], stderr=open(os.devnull, 'w')).decode("ascii")
  26     except:
  27         # don't print anything if it fails
  28         git_sha1 = ''
  29     return git_sha1
  30
  31 def write_if_different(contents):
  32     """
  33     Avoid touching the output file if it doesn't need modifications
  34     Useful to avoid triggering rebuilds when nothing has changed.
  35     """
  36     if os.path.isfile(args.output):
  37         with open(args.output, 'r') as file:
  38             if file.read() == contents:
  39                 return
  40     with open(args.output, 'w') as file:
  41         file.write(contents)
  42
  43 parser = argparse.ArgumentParser()
  44 parser.add_argument('--output', help='File to write the #define in',
  45                     required=True)
  46 args = parser.parse_args()
  47
  48 git_sha1 = os.environ.get('MESA_GIT_SHA1_OVERRIDE', get_git_sha1())[:10]
  49 if git_sha1:
  50     write_if_different('#define MESA_GIT_SHA1 "git-' + git_sha1 + '"')
  51 else:
  52     write_if_different('')