Add watchlists to 'gcl upload'

Watchlists provides an opportunity for someone interested in a particular
code section to make comments before commit. One can subscribe to watchlists
depending on filepath (regular expressions) and she'll automatically get
cc-ed to changes when the watchlist is triggered.

Additional examples of watchlist_rules in diff repo:
http://codereview.chromium.org/118431
http://codereview.chromium.org/119356
Review URL: http://codereview.chromium.org/118432

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@18209 0039d316-1c4b-4281-b951-d872f2087c98

WATCHLISTS

+# 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.
+
+# Watchlist Rules
+# Refer: http://dev.chromium.org/developers/contributing-code/watchlists
+
+{
+
+  'WATCHLIST_DEFINITIONS': {
+    'this_file': {
+      'filepath': '^WATCHLISTS$',
+    },
+    'depot_tools': {
+      'filepath': '.+',
+    },
+  },
+
+  'WATCHLISTS': {
+    'this_file': ['nirnimesh@chromium.org'],
+    'depot_tools': ['maruel@chromium.org'],
+  },
+
+}

gcl.py

@@ -615,6 +615,7 @@ Basic commands:
 
    gcl upload change_name [-r reviewer1@gmail.com,reviewer2@gmail.com,...]
                           [--send_mail] [--no_try] [--no_presubmit]
+                          [--no_watchlists]
       Uploads the changelist to the server for review.
 
    gcl commit change_name [--no_presubmit]
@@ -738,6 +739,8 @@ def UploadCL(change_info, args):
   if not OptionallyDoPresubmitChecks(change_info, False, args):
     return
   no_try = FilterFlag(args, "--no_try") or FilterFlag(args, "--no-try")
+  no_watchlists = FilterFlag(args, "--no_watchlists") or \
+                  FilterFlag(args, "--no-watchlists")
 
   # Map --send-mail to --send_mail
   if FilterFlag(args, "--send-mail"):
@@ -775,7 +778,17 @@ def UploadCL(change_info, args):
     os.write(handle, change_info.description)
     os.close(handle)
 
+    # Watchlist processing -- CC people interested in this changeset
+    # http://dev.chromium.org/developers/contributing-code/watchlists
+    if not no_watchlists:
+      import watchlists
+      watchlist = watchlists.Watchlists(GetRepositoryRoot())
+      watchers = watchlist.GetWatchersForPaths(change_info.FileList())
+
     cc_list = GetCodeReviewSetting("CC_LIST")
+    if not no_watchlists and watchers:
+        # Filter out all empty elements and join by ','
+        cc_list = ','.join(filter(None, [cc_list] + watchers))
     if cc_list:
       upload_arg.append("--cc=" + cc_list)
     upload_arg.append("--description_file=" + desc_file + "")

watchlists.py

+#!/usr/bin/python
+# Copyright (c) 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.
+
+"""Watchlists
+
+Watchlists is a mechanism that allow a developer (a "watcher") to watch over
+portions of code that he is interested in. A "watcher" will be cc-ed to
+changes that modify that portion of code, thereby giving him an opportunity
+to make comments on codereview.chromium.org even before the change is
+committed.
+Refer: http://dev.chromium.org/developers/contributing-code/watchlists
+
+When invoked directly from the base of a repository, this script lists out
+the watchers for files given on the command line. This is useful to verify
+changes to WATCHLISTS files.
+"""
+
+import logging
+import os
+import re
+import sys
+
+
+class Watchlists(object):
+  """Manage Watchlists.
+
+  This class provides mechanism to load watchlists for a repo and identify
+  watchers.
+  Usage:
+    wl = Watchlists("/path/to/repo/root")
+    watchers = wl.GetWatchersForPaths(["/path/to/file1",
+                                       "/path/to/file2",])
+  """
+
+  _RULES = "WATCHLISTS"
+  _RULES_FILENAME = _RULES
+  _repo_root = None
+  _defns = {}       # Definitions
+  _watchlists = {}  # name to email mapping
+
+  def __init__(self, repo_root):
+    self._repo_root = repo_root
+    self._LoadWatchlistRules()
+
+  def _GetRulesFilePath(self):
+    return os.path.join(self._repo_root, self._RULES_FILENAME)
+
+  def _HasWatchlistsFile(self):
+    """Determine if watchlists are available for this repo."""
+    return os.path.exists(self._GetRulesFilePath())
+
+  def _LoadWatchlistRules(self):
+    if not self._HasWatchlistsFile():
+      return
+    watchlists_file = open(self._GetRulesFilePath())
+    contents = watchlists_file.read()
+    watchlists_file.close()
+
+    watchlists_data = None
+    try:
+      watchlists_data = eval(contents, {'__builtins__': None}, None)
+    except SyntaxError, e:
+      logging.error("Cannot parse %s. %s" % (self._GetRulesFilePath(), e))
+      return
+
+    defns = watchlists_data.get("WATCHLIST_DEFINITIONS")
+    if not defns:
+      logging.error("WATCHLIST_DEFINITIONS not defined in %s" %
+                    self._GetRulesFilePath())
+      return
+    watchlists = watchlists_data.get("WATCHLISTS")
+    if not watchlists:
+      logging.error("WATCHLISTS not defined in %s" % self._GetRulesFilePath())
+      return
+    self._defns = defns
+    self._watchlists = watchlists
+
+    # Verify that all watchlist names are defined
+    for name in watchlists:
+      if name not in defns:
+        logging.error("%s not defined in %s" % (name, self._GetRulesFilePath()))
+
+  def GetWatchersForPaths(self, paths):
+    """Fetch the list of watchers for |paths|
+
+    Args:
+      paths: [path1, path2, ...]
+
+    Returns:
+      [u1@chromium.org, u2@gmail.com, ...]
+    """
+    watchers = set()  # A set, to avoid duplicates
+    for path in paths:
+      for name, rule in self._defns.iteritems():
+        if name not in self._watchlists: continue
+        rex_str = rule.get('filepath')
+        if not rex_str: continue
+        if re.search(rex_str, path):
+          map(watchers.add, self._watchlists[name])
+    return list(watchers)
+
+
+def main(argv):
+  # Confirm that watchlists can be parsed and spew out the watchers
+  if len(argv) < 2:
+    print "Usage (from the base of repo):"
+    print "  %s [file-1] [file-2] ...." % argv[0]
+    return 1
+  wl = Watchlists(os.getcwd())
+  watchers = wl.GetWatchersForPaths(argv[1:])
+  print watchers
+
+
+if __name__ == '__main__':
+  main(sys.argv)