Patch path filtering script.

scripts/slave/patch_path_filter.py

Index: scripts/slave/patch_path_filter.py
diff --git a/scripts/slave/patch_path_filter.py b/scripts/slave/patch_path_filter.py
new file mode 100755
index 0000000000000000000000000000000000000000..24b7281bf05b9ed2ad88aba08ee688569fe5be18
--- /dev/null
+++ b/scripts/slave/patch_path_filter.py
@@ -0,0 +1,97 @@
+#!/usr/bin/python
+# Copyright 2013 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.
+
+"""Script that can be used to filter out files from a patch/diff.
+
+Just pipe the patch contents to stdin and the filtered output will be written
+to stdout.
+"""
+
+import optparse
+import os
+import re
+import sys
+
+from depot_tools import patch
+
+_GIT_PREFIX = 'diff --git '
+_SVN_PREFIX = 'Index: '
+
+# The Git patches generated from depot_tools/git_cl.py has the a/ prefix for
+# the source files stripped out. That's why it's optional non-capturing group
+# below (to support both scenarios).
+_GIT_FILENAME_REGEX = r'^diff \-\-git (?:a/)?(.*?) .*\n$'
+_SVN_FILENAME_REGEX = r'^Index: ([^\t]+).*\n$'
+
+
+def parse_git_patch_set(patch_contents):
+  return _parse_patch_set(_GIT_PREFIX, _GIT_FILENAME_REGEX, patch_contents)
+
+def parse_svn_patch_set(patch_contents):
+  return _parse_patch_set(_SVN_PREFIX, _SVN_FILENAME_REGEX, patch_contents)
+
+def _parse_patch_set(prefix, filename_pattern, patch_contents):
+  # Parse into chunks using the prefix.
+  patch_chunks = []
+  current_chunk = []
+  for line in patch_contents.splitlines(True):
+    if line.startswith(prefix) and current_chunk:
+      patch_chunks.insert(0, current_chunk)
+      current_chunk = [line]
+    else:
+      current_chunk.append(line)
+  if current_chunk:
+    patch_chunks.insert(0, current_chunk)
+
+  # Parse filename for each patch chunk and create FilePatchDiff objects
+  filename_regex = re.compile(filename_pattern)
+  patches = []
+  for chunk in patch_chunks:
+    match = filename_regex.match(chunk[0])
+    if not match:
+      raise Exception('Did not find any filename in %s' % chunk[0])
+    filename = match.group(1).replace('\\', '/')
+    diff = ''.join(chunk)
+    patches.append(patch.FilePatchDiff(filename=filename, diff=diff,
+                                       svn_properties=[]))
+  return patch.PatchSet(patches)
+
+def main():
+  usage = '%s -f <path-filter> [-r <root-dir>]' % os.path.basename(sys.argv[0])
+  parser = optparse.OptionParser(usage=usage)
+  parser.add_option('-f', '--path-filter',
+                    help=('The path filter (UNIX paths) that all file paths '
+                          'are required to have to pass this filter (no '
+                          'regexp).'))
+  parser.add_option('-r', '--root-dir',
+                    help=('The patch root dir in which to apply the patch. If '
+                          'specified, it will be prepended to the filename '
+                          'for each patch entry before the filter is applied.'))
+
+  options, args = parser.parse_args()
+  if args:
+    parser.error('Unused args: %s' % args)
+  if not options.path_filter:
+    parser.error('A path filter must be be specified.')
+
+  patch_contents = sys.stdin.read()
+
+  # Find out if it's a Git or Subversion patch set.
+  is_git = any(l.startswith(_GIT_PREFIX) for l in patch_contents.splitlines())

[kjellander_chromium, 2013/12/10 20:46:02]

Turns out this is actually not needed if we assume we're working with only depot
tools generated patches (that all have Index: in the beginning of each patch
chunk)

+  if is_git:
+    patchset = parse_git_patch_set(patch_contents)
+  else:
+    patchset = parse_svn_patch_set(patch_contents)
+
+  # Only print the patch entries that passes our path filter.
+  for patch_entry in patchset:
+    filename = patch_entry.filename
+    if options.root_dir:
+      filename = os.path.join(options.root_dir, filename)
+    if filename.startswith(options.path_filter):
+      print patch_entry.get(for_git=is_git)
+
+if __name__ == '__main__':
+  sys.exit(main())