utils/gn/build/write_vcsrevision.py

   1 #!/usr/bin/env python
   2
   3 """Gets the current revision and writes it to VCSRevision.h."""
   4
   5 from __future__ import print_function
   6
   7 import argparse
   8 import os
   9 import subprocess
  10 import sys
  11
  12
  13 THIS_DIR = os.path.abspath(os.path.dirname(__file__))
  14 LLVM_DIR = os.path.dirname(os.path.dirname(os.path.dirname(THIS_DIR)))
  15
  16
  17 def which(program):
  18     # distutils.spawn.which() doesn't find .bat files,
  19     # https://bugs.python.org/issue2200
  20     for path in os.environ["PATH"].split(os.pathsep):
  21         candidate = os.path.join(path, program)
  22         if os.path.isfile(candidate) and os.access(candidate, os.X_OK):
  23             return candidate
  24     return None
  25
  26
  27 def main():
  28     parser = argparse.ArgumentParser(description=__doc__)
  29     parser.add_argument('-d', '--depfile',
  30                         help='if set, writes a depfile that causes this script '
  31                              'to re-run each time the current revision changes')
  32     parser.add_argument('vcs_header', help='path to the output file to write')
  33     args = parser.parse_args()
  34
  35     if os.path.isdir(os.path.join(LLVM_DIR, '.svn')):
  36         print('SVN support not implemented', file=sys.stderr)
  37         return 1
  38     if os.path.exists(os.path.join(LLVM_DIR, '.git')):
  39         print('non-mono-repo git support not implemented', file=sys.stderr)
  40         return 1
  41
  42     git, use_shell = which('git'), False
  43     if not git:
  44         git = which('git.exe')
  45     if not git:
  46         git = which('git.bat')
  47         use_shell = True
  48
  49     git_dir = subprocess.check_output([git, 'rev-parse', '--git-dir'],
  50                                       cwd=LLVM_DIR, shell=use_shell).decode().strip()
  51     if not os.path.isdir(git_dir):
  52         print('.git dir not found at "%s"' % git_dir, file=sys.stderr)
  53         return 1
  54
  55     rev = subprocess.check_output([git, 'rev-parse', '--short', 'HEAD'],
  56                                   cwd=git_dir, shell=use_shell).decode().strip()
  57     # FIXME: add pizzas such as the svn revision read off a git note?
  58     vcsrevision_contents = '#define LLVM_REVISION "git-%s"\n' % rev
  59
  60     # If the output already exists and is identical to what we'd write,
  61     # return to not perturb the existing file's timestamp.
  62     if os.path.exists(args.vcs_header) and \
  63             open(args.vcs_header).read() == vcsrevision_contents:
  64         return 0
  65
  66     # http://neugierig.org/software/blog/2014/11/binary-revisions.html
  67     if args.depfile:
  68         build_dir = os.getcwd()
  69         with open(args.depfile, 'w') as depfile:
  70             depfile.write('%s: %s\n' % (
  71                 args.vcs_header,
  72                 os.path.relpath(os.path.join(git_dir, 'logs', 'HEAD'),
  73                                 build_dir)))
  74     open(args.vcs_header, 'w').write(vcsrevision_contents)
  75
  76
  77 if __name__ == '__main__':
  78     sys.exit(main())