Factor out PathDifference into gclient_utils for a later reuse.

gcl.py

 #!/usr/bin/python
 # Copyright (c) 2006-2009 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.
 
 """Wrapper script around Rietveld's upload.py that groups files into
 changelists."""
 
 import getpass
 import os
@@ skipping 801 matching lines @@
 
 def TryChange(change_info, args, swallow_exception):
   """Create a diff file of change_info and send it to the try server."""
   try:
     import trychange
   except ImportError:
     if swallow_exception:
       return
     ErrorExit("You need to install trychange.py to use the try server.")
 
-  def PathDifference(root, subpath):
-    """Returns the difference subpath minus root."""
-    root = os.path.realpath(root)
-    subpath = os.path.realpath(subpath)
-    if not subpath.startswith(root):
-      return None
-    # If the root does not have a trailing \ or /, we add it so the returned
-    # path starts immediately after the seperator regardless of whether it is
-    # provided.
-    root = os.path.join(root, '')
-    return subpath[len(root):]
-
   trychange_args = []
   settings = {
     'port': GetCodeReviewSetting('TRYSERVER_HTTP_PORT'),
     'host': GetCodeReviewSetting('TRYSERVER_HTTP_HOST'),
     'svn_repo': GetCodeReviewSetting('TRYSERVER_SVN_URL'),
     'project': GetCodeReviewSetting('TRYSERVER_PROJECT'),
     'root': GetCodeReviewSetting('TRYSERVER_ROOT'),
     'patchlevel': GetCodeReviewSetting('TRYSERVER_PATCHLEVEL'),
   }
   for (k, v) in settings.iteritems():
     if v:
       trychange_args.extend(['--' + k, v])
 
   gclient_root = gclient_utils.FindGclientRoot(GetRepositoryRoot())
   if gclient_root:
-    trychange_args.extend(['--root', PathDifference(gclient_root,
-                                                    GetRepositoryRoot())])
+    trychange_args.extend(['--root',
+                           gclient_utils.PathDifference(gclient_root,
+                                                        GetRepositoryRoot())])
   if change_info:
     trychange_args.extend(['--name', change_info.name])
     if change_info.issue:
       trychange_args.extend(["--issue", str(change_info.issue)])
     if change_info.patchset:
       trychange_args.extend(["--patchset", str(change_info.patchset)])
     trychange_args.extend(args)
     file_list = change_info.GetFileNames()
   else:
     trychange_args.extend(args)
@@ skipping 368 matching lines @@
       return 0
     args =["svn", command]
     root = GetRepositoryRoot()
     args.extend([os.path.join(root, x) for x in change_info.GetFileNames()])
     RunShell(args, True)
   return 0
 
 
 if __name__ == "__main__":
   sys.exit(main())