Add presubmit checks and watchlist for FFmpeg repo.

PRESUBMIT.py

Index: PRESUBMIT.py
diff --git a/PRESUBMIT.py b/PRESUBMIT.py
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+++ b/PRESUBMIT.py
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+# 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.
+
+"""Presubmit script for FFmpeg repository.
+
+Does the following:
+- Displays a message indicating that all changes must be pushed to SVN.
+- Prevents changes inside the git-svn and svn repositories.
+- Warns users when a change is made without updating the README file.
+"""
+
+import re
+import subprocess
+
+
+# Setup some basic ANSI colors.
+BOLD_RED = '\033[1;31m'
+BOLD_BLUE = '\033[1;34m'
+
+
+def Color(color, string):
+  return ''.join([color, string, '\033[m'])
+
+
+def _CheckForMainRepository(input_api, output_api):
+  """Ensure no commits are allowed to the Subversion repository."""
+  try:
+    stdout = subprocess.Popen('git config --get remote.origin.url', shell=True,
+                              cwd=input_api.PresubmitLocalPath(),
+                              stdout=subprocess.PIPE).communicate()[0]
+    if 'chromium/third_party/ffmpeg.git' in stdout:
+      return []
+  except Exception, e:
+    # Not everyone has a working Git configuration, so print the exception text
+    # and move on.
+    print e
+
+  return [output_api.PresubmitError('\n'.join([
+      'Commits to the FFmpeg repository must be made through Git. The easiest',
+      'way to do this is to switch to using NewGit:\n',
+      '   http://code.google.com/p/chromium/wiki/UsingNewGit\n',
+      'Alternatively, you can clone the repository directly using:\n',
+      '   git clone http://git.chromium.org/chromium/third_party/ffmpeg.git']))]
+
+
+def _WarnAboutManualSteps():
+  """Warn about the manual steps required for rolling the FFmpeg repository."""
+  print Color(BOLD_RED, '[ REMEMBER ]'.center(70, '*'))
+  print Color(
+      BOLD_BLUE, '\n'.join([
+          'Updates to FFmpeg require the following additional manual steps:',
+          '  - Rebuild and commit of Chrome and Chromium Windows DLLs.',
+          '  - Push of new sources from Git to Subversion. See sync_svn.py.',
+          '  - Internal and external DEPS roll.',
+          '  - If new source files were added, generate_gyp.py must be run.\n',
+          'For help, please consult the following resources:',
+          '  - chromium/README.chromium help text.',
+          '  - Chromium development list: chromium-dev@chromium.org',
+          '  - "Communication" section of http://www.chromium.org/developers']))
+  print Color(BOLD_RED, 70 * '*')
+
+
+def _WarnIfReadmeIsUnchanged(input_api, output_api):
+  """Warn if the README file hasn't been updated with change notes."""
+  readme_re = re.compile(r'.*[/\\]chromium[/\\]patches[/\\]README$')
+  for f in input_api.AffectedSourceFiles(input_api.FilterSourceFile):
+    if readme_re.match(f.LocalPath()):
+      return []
+
+  return [output_api.PresubmitPromptWarning('\n'.join([
+      'FFmpeg changes detected without any update to chromium/patches/README,',
+      'it\'s good practice to update this file with a note about your changes.'
+  ]))]
+
+
+def CheckChangeOnUpload(input_api, output_api):
+  _WarnAboutManualSteps()
+  results = []
+  results.extend(_CheckForMainRepository(input_api, output_api))
+  results.extend(_WarnIfReadmeIsUnchanged(input_api, output_api))
+  return results