Add 'git cl diff' command.

git_cl.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.
 
 # Copyright (C) 2008 Evan Martin <martine@danga.com>
 
 """A git-command for integrating reviews on Rietveld."""
 
 from distutils.version import LooseVersion
@@ skipping 1843 matching lines @@
                     help="don't commit after patch applies")
   (options, args) = parser.parse_args(args)
   if len(args) != 1:
     parser.print_help()
     return 1
   issue_arg = args[0]
 
   # TODO(maruel): Use apply_issue.py
   # TODO(ukai): use gerrit-cherry-pick for gerrit repository?
 
-  if issue_arg.isdigit():
+  if options.newbranch:
+    if options.force:
+      RunGit(['branch', '-D', options.newbranch],
+          stderr=subprocess2.PIPE, error_ok=True)
+    RunGit(['checkout', '-b', options.newbranch,
+            Changelist().GetUpstreamBranch()])
+
+  return PatchIssue(issue_arg, options.reject, options.nocommit)
+
+
+def PatchIssue(issue_arg, reject, nocommit):
+  if type(issue_arg) is int or issue_arg.isdigit():
     # Input is an issue id.  Figure out the URL.
     issue = int(issue_arg)
     cl = Changelist(issue=issue)
     patchset = cl.GetMostRecentPatchset()
     patch_data = cl.GetPatchSetDiff(issue, patchset)
   else:
     # Assume it's a URL to the patch. Default to https.
     issue_url = gclient_utils.UpgradeToHttps(issue_arg)
     match = re.match(r'.*?/issue(\d+)_(\d+).diff', issue_url)
     if not match:
       DieWithError('Must pass an issue ID or full URL for '
           '\'Download raw patch set\'')
     issue = int(match.group(1))
     patchset = int(match.group(2))
     patch_data = urllib2.urlopen(issue_arg).read()
 
-  if options.newbranch:
-    if options.force:
-      RunGit(['branch', '-D', options.newbranch],
-          stderr=subprocess2.PIPE, error_ok=True)
-    RunGit(['checkout', '-b', options.newbranch,
-            Changelist().GetUpstreamBranch()])
-
   # Switch up to the top-level directory, if necessary, in preparation for
   # applying the patch.
   top = RunGit(['rev-parse', '--show-cdup']).strip()
   if top:
     os.chdir(top)
 
   # Git patches have a/ at the beginning of source paths.  We strip that out
   # with a sed script rather than the -p flag to patch so we can feed either
   # Git or svn-style patches into the same apply command.
   # re.sub() should be used but flags=re.MULTILINE is only in python 2.7.
   try:
     patch_data = subprocess2.check_output(
         ['sed', '-e', 's|^--- a/|--- |; s|^+++ b/|+++ |'], stdin=patch_data)
   except subprocess2.CalledProcessError:
     DieWithError('Git patch mungling failed.')
   logging.info(patch_data)
   env = os.environ.copy()
   # 'cat' is a magical git string that disables pagers on all platforms.
   env['GIT_PAGER'] = 'cat'
 
   # We use "git apply" to apply the patch instead of "patch" so that we can
   # pick up file adds.
   # The --index flag means: also insert into the index (so we catch adds).
   cmd = ['git', 'apply', '--index', '-p0']
-  if options.reject:
+  if reject:
     cmd.append('--reject')
   elif IsGitVersionAtLeast('1.7.12'):
     cmd.append('--3way')
   try:
     subprocess2.check_call(cmd, env=env,
                            stdin=patch_data, stdout=subprocess2.VOID)
   except subprocess2.CalledProcessError:
     DieWithError('Failed to apply the patch')
 
   # If we had an issue, commit the current state and register the issue.
-  if not options.nocommit:
+  if not nocommit:
     RunGit(['commit', '-m', 'patch from issue %s' % issue])
     cl = Changelist()
     cl.SetIssue(issue)
     cl.SetPatchset(patchset)
     print "Committed patch locally."
   else:
     print "Patch applied to index."
   return 0
 
 
@@ skipping 187 matching lines @@
   _, args = parser.parse_args(args)
   if args:
     parser.error('Unrecognized args: %s' % ' '.join(args))
   cl = Changelist()
   # Ensure there actually is an issue to close.
   cl.GetDescription()
   cl.CloseIssue()
   return 0
 
 
+def CMDdiff(parser, args):
+  """shows differences between local tree and last upload."""
+  cl = Changelist()
+  branch = cl.GetBranch()
+  TMP_BRANCH = 'git-cl-diff'
+  base_branch = RunGit(['merge-base', cl.GetUpstreamBranch(), 'HEAD']).strip()
+
+  # Create a new branch based on the merge-base
+  RunGit(['checkout', '-q', '-b', TMP_BRANCH, base_branch])
+  try:
+    # Patch in the latest changes from rietveld.
+    rtn = PatchIssue(cl.GetIssue(), False, False)
+    if rtn != 0:
+      return rtn
+
+    # Switch back to starting brand and diff against the temporary
+    # branch containing the latest rietveld patch.
+    subprocess2.check_call(['git', 'diff', TMP_BRANCH, branch])
+  finally:
+    RunGit(['checkout', '-q', branch])
+    RunGit(['branch', '-D', TMP_BRANCH])
+
+  return 0
+
+
 def CMDowners(parser, args):
   """interactively find the owners for reviewing"""
   parser.add_option(
       '--no-color',
       action='store_true',
       help='Use this option to disable color output')
   options, args = parser.parse_args(args)
 
   author = RunGit(['config', 'user.email']).strip() or None
 
@@ skipping 115 matching lines @@
         ('AppEngine is misbehaving and returned HTTP %d, again. Keep faith '
           'and retry or visit go/isgaeup.\n%s') % (e.code, str(e)))
 
 
 if __name__ == '__main__':
   # These affect sys.stdout so do it outside of main() to simplify mocks in
   # unit testing.
   fix_encoding.fix_encoding()
   colorama.init()
   sys.exit(main(sys.argv[1:]))