lastchange: add a flag to only print the svn revision number

build/util/lastchange.py

 #!/usr/bin/env python
 # Copyright (c) 2010 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 optparse
@@ skipping 53 matching lines @@
     if contents == old_contents:
       return
     os.unlink(file_name)
   open(file_name, 'w').write(contents)
 
 
 def main(argv=None):
   if argv is None:
     argv = sys.argv
 
-  parser = optparse.OptionParser(usage="lastchange.py [-h] [[-o] FILE]")
+  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")
   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)
 
   change = FetchChange(opts.default_lastchange)
 
-  contents = "LASTCHANGE=%s\n" % change
-
-  if out_file:
-    WriteIfChanged(out_file, contents)
+  if opts.revision_only:
+    print change
   else:
-    sys.stdout.write(contents)
+    contents = "LASTCHANGE=%s\n" % change
+    if out_file:
+      WriteIfChanged(out_file, contents)
+    else:
+      sys.stdout.write(contents)
 
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main())