Added git footers tool to parse conventional metadata from git commits
BUG=407316
Review URL: https://codereview.chromium.org/521033002
git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@291777 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/git_footers.py b/git_footers.py
new file mode 100755
index 0000000..b08d464
--- /dev/null
+++ b/git_footers.py
@@ -0,0 +1,131 @@
+#!/usr/bin/env python
+# Copyright 2014 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.
+
+import argparse
+import re
+import sys
+
+from collections import defaultdict
+
+import git_common as git
+
+FOOTER_PATTERN = re.compile(r'^\s*([\w-]+): (.*)$')
+CHROME_COMMIT_POSITION_PATTERN = re.compile(r'^([\w/-]+)@{#(\d+)}$')
+GIT_SVN_ID_PATTERN = re.compile('^([^\s@]+)@(\d+)')
+
+def normalize_name(header):
+ return '-'.join([ word.title() for word in header.strip().split('-') ])
+
+
+def parse_footer(line):
+ match = FOOTER_PATTERN.match(line)
+ if match:
+ return (match.group(1), match.group(2))
+ else:
+ return None
+
+
+def parse_footers(message):
+ """Parses a git commit message into a multimap of footers."""
+ footer_lines = []
+ for line in reversed(message.splitlines()):
+ if line == '' or line.isspace():
+ break
+ footer_lines.append(line)
+
+ footers = map(parse_footer, footer_lines)
+ if not all(footers):
+ return defaultdict(list)
+
+ footer_map = defaultdict(list)
+ for (k, v) in footers:
+ footer_map[normalize_name(k)].append(v.strip())
+
+ return footer_map
+
+
+def get_unique(footers, key):
+ key = normalize_name(key)
+ values = footers[key]
+ assert len(values) <= 1, 'Multiple %s footers' % key
+ if values:
+ return values[0]
+ else:
+ return None
+
+
+def get_position(footers):
+ """Get the chrome commit position from a footer multimap using a heuristic.
+
+ Returns:
+ A tuple of the branch and the position on that branch. For example,
+
+ Cr-Commit-Position: refs/heads/master@{#292272}
+
+ would give the return value ('refs/heads/master', 292272). If
+ Cr-Commit-Position is not defined, we try to infer the ref and position
+ from git-svn-id. The position number can be None if it was not inferrable.
+ """
+
+ position = get_unique(footers, 'Cr-Commit-Position')
+ if position:
+ match = CHROME_COMMIT_POSITION_PATTERN.match(position)
+ assert match, 'Invalid Cr-Commit-Position value: %s' % position
+ return (match.group(1), match.group(2))
+
+ svn_commit = get_unique(footers, 'git-svn-id')
+ if svn_commit:
+ match = GIT_SVN_ID_PATTERN.match(svn_commit)
+ assert match, 'Invalid git-svn-id value: %s' % svn_commit
+ if re.match('.*/chrome/trunk/src$', match.group(1)):
+ return ('refs/heads/master', match.group(2))
+ branch_match = re.match('.*/chrome/branches/([\w/-]+)/src$', match.group(1))
+ if branch_match:
+ # svn commit numbers do not map to branches.
+ return ('refs/branch-heads/%s' % branch_match.group(1), None)
+
+ raise ValueError('Unable to infer commit position from footers')
+
+
+def main(args):
+ parser = argparse.ArgumentParser(
+ formatter_class=argparse.ArgumentDefaultsHelpFormatter
+ )
+ parser.add_argument('ref')
+
+ g = parser.add_mutually_exclusive_group()
+ g.add_argument('--key', metavar='KEY',
+ help='Get all values for the given footer name, one per '
+ 'line (case insensitive)')
+ g.add_argument('--position', action='store_true')
+ g.add_argument('--position-ref', action='store_true')
+ g.add_argument('--position-num', action='store_true')
+
+
+ opts = parser.parse_args(args)
+
+ message = git.run('log', '-1', '--format=%B', opts.ref)
+ footers = parse_footers(message)
+
+ if opts.key:
+ for v in footers.get(normalize_name(opts.key), []):
+ print v
+ elif opts.position:
+ pos = get_position(footers)
+ print '%s@{#%s}' % (pos[0], pos[1] or '?')
+ elif opts.position_ref:
+ print get_position(footers)[0]
+ elif opts.position_num:
+ pos = get_position(footers)
+ assert pos[1], 'No valid position for commit'
+ print pos[1]
+ else:
+ for k in footers.keys():
+ for v in footers[k]:
+ print '%s: %s' % (k, v)
+
+
+if __name__ == '__main__':
+ sys.exit(main(sys.argv[1:]))