Fix running presubmit_support.py directly

presubmit_support.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.
 
 """Enables directory-specific presubmit checks to run at upload and/or commit.
 """
 
 __version__ = '1.6.1'
 
@@ skipping 1165 matching lines @@
   files = []
   for arg in args:
     files.extend([('M', f) for f in ScanSubDirs(arg, recursive)])
   return files
 
 
 def load_files(options, args):
   """Tries to determine the SCM."""
   change_scm = scm.determine_scm(options.root)
   files = []
+  if args:
+    files = ParseFiles(args, options.recursive)
   if change_scm == 'svn':
     change_class = SvnChange
-    status_fn = scm.SVN.CaptureStatus
+    if not files:
+      files = scm.SVN.CaptureStatus([], options.root)
   elif change_scm == 'git':
     change_class = GitChange
-    status_fn = scm.GIT.CaptureStatus
+    # TODO(maruel): Get upstream.
+    if not files:
+      files = scm.GIT.CaptureStatus([], options.root, None)
   else:
     logging.info('Doesn\'t seem under source control. Got %d files' % len(args))
-    if not args:
+    if not files:
       return None, None
     change_class = Change
-  if args:
-    files = ParseFiles(args, options.recursive)
-  else:
-    # Grab modified files.
-    files = status_fn([options.root])
   return change_class, files
 
 
 def Main(argv):
   parser = optparse.OptionParser(usage="%prog [options] <files...>",
                                  version="%prog " + str(__version__))
   parser.add_option("-c", "--commit", action="store_true", default=False,
                    help="Use commit instead of upload checks")
   parser.add_option("-u", "--upload", action="store_false", dest='commit',
                    help="Use upload instead of commit checks")
@@ skipping 53 matching lines @@
   except PresubmitFailure, e:
     print >> sys.stderr, e
     print >> sys.stderr, 'Maybe your depot_tools is out of date?'
     print >> sys.stderr, 'If all fails, contact maruel@'
     return 2
 
 
 if __name__ == '__main__':
   fix_encoding.fix_encoding()
   sys.exit(Main(None))