Allow lastchange.py to be used for arbitrary repositories.

build/util/lastchange.py

 #!/usr/bin/env python
 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """
 lastchange.py -- Chromium revision fetching utility.
 """
 
 import re
@@ skipping 178 matching lines @@
   if argv is None:
     argv = sys.argv
 
   parser = optparse.OptionParser(usage="lastchange.py [options]")
   parser.add_option("-d", "--default-lastchange", metavar="FILE",
                     help="default last change input FILE")
   parser.add_option("-o", "--output", metavar="FILE",
                     help="write last change to FILE")
   parser.add_option("--revision-only", action='store_true',
                     help="just print the SVN revision number")
+  parser.add_option("-s", "--source-dir", metavar="DIR",
+                    help="use repository in the given directory")
   opts, args = parser.parse_args(argv[1:])
 
   out_file = opts.output
 
   while len(args) and out_file is None:
     if out_file is None:
       out_file = args.pop(0)
   if args:
     sys.stderr.write('Unexpected arguments: %r\n\n' % args)
     parser.print_help()
     sys.exit(2)
 
-  version_info = FetchVersionInfo(opts.default_lastchange,
-      os.path.dirname(sys.argv[0]))
+  if opts.source_dir:
+    src_dir = opts.source_dir
+  else:
+    src_dir = os.path.dirname(os.path.abspath(__file__))
+
+  version_info = FetchVersionInfo(opts.default_lastchange, src_dir)
 
   if version_info.revision == None:
     version_info.revision = '0'
 
   if opts.revision_only:
     print version_info.revision
   else:
     contents = "LASTCHANGE=%s\n" % version_info.revision
     if out_file:
       WriteIfChanged(out_file, contents)
     else:
       sys.stdout.write(contents)
 
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main())