1#!/usr/bin/env python
2# Copyright (c) 2011 The Chromium Authors. All rights reserved.
3# Use of this source code is governed by a BSD-style license that can be
4# found in the LICENSE file.
5
6"""Update third_party/WebKit using git.
7
8Under the assumption third_party/WebKit is a clone of git.webkit.org,
9we can use git commands to make it match the version requested by DEPS.
10
11See http://code.google.com/p/chromium/wiki/UsingWebKitGit for details on
12how to use this.
13"""
14
15import logging
16import optparse
17import os
18import re
19import subprocess
20import sys
21import urllib
22
23
24def RunGit(command):
25  """Run a git subcommand, returning its output."""
26  # On Windows, use shell=True to get PATH interpretation.
27  command = ['git'] + command
28  logging.info(' '.join(command))
29  shell = (os.name == 'nt')
30  proc = subprocess.Popen(command, shell=shell, stdout=subprocess.PIPE)
31  out = proc.communicate()[0].strip()
32  logging.info('Returned "%s"' % out)
33  return out
34
35
36def GetOverrideShortBranchName():
37  """Returns the user-configured override branch name, if any."""
38  override_config_name = 'chromium.sync-branch'
39  return RunGit(['config', '--get', override_config_name])
40
41
42def GetGClientBranchName():
43  """Returns the name of the magic branch that lets us know that DEPS is
44  managing the update cycle."""
45  # Is there an override branch specified?
46  override_branch_name = GetOverrideShortBranchName()
47  if not override_branch_name:
48    return 'refs/heads/gclient' # No override, so return the default branch.
49
50  # Verify that the branch from config exists.
51  ref_branch = 'refs/heads/' + override_branch_name
52  current_head = RunGit(['show-ref', '--hash', ref_branch])
53  if current_head:
54    return ref_branch
55
56  # Inform the user about the problem and how to fix it.
57  print ("The specified override branch ('%s') doesn't appear to exist." %
58         override_branch_name)
59  print "Please fix your git config value '%s'." % overide_config_name
60  sys.exit(1)
61
62
63def GetWebKitRev():
64  """Extract the 'webkit_revision' variable out of DEPS."""
65  locals = {'Var': lambda _: locals["vars"][_],
66            'From': lambda *args: None}
67  execfile('DEPS', {}, locals)
68  return locals['vars']['webkit_revision']
69
70
71def GetWebKitRevFromTarball(version):
72  """Extract the 'webkit_revision' variable out of tarball DEPS."""
73  deps_url = "http://src.chromium.org/svn/releases/" + version + "/DEPS"
74  f = urllib.urlopen(deps_url)
75  s = f.read()
76  m = re.search('(?<=/Source@)\w+', s)
77  return m.group(0)
78
79
80def HasGitRev(target_rev):
81  """Finds if a git hash exists in the repository."""
82
83  cmd = ['git', 'rev-list', '--max-count=1', target_rev]
84  logging.info(' '.join(cmd))
85  result = subprocess.call(cmd, shell=(os.name == 'nt'), stdout=subprocess.PIPE)
86  return result == 0
87
88
89def GetRemote():
90  branch = GetOverrideShortBranchName()
91  if not branch:
92    branch = 'gclient'
93
94  remote = RunGit(['config', '--get', 'branch.' + branch + '.remote'])
95  if remote:
96    return remote
97  return 'origin'
98
99
100def UpdateGClientBranch(webkit_rev, magic_gclient_branch):
101  """Update the magic gclient branch to point at |webkit_rev|.
102
103  Returns: true if the branch didn't need changes."""
104  if not HasGitRev(webkit_rev):
105    print "%s not available; fetching." % webkit_rev
106    subprocess.check_call(['git', 'fetch', GetRemote()],
107                          shell=(os.name == 'nt'))
108    if not HasGitRev(webkit_rev):
109      print "ERROR: Couldn't find %s in the repository." % webkit_rev
110      sys.exit(1)
111
112  current = RunGit(['show-ref', '--hash', magic_gclient_branch])
113  if current == webkit_rev:
114    return False  # No change necessary.
115
116  subprocess.check_call(['git', 'update-ref', '-m', 'gclient sync',
117                         magic_gclient_branch, webkit_rev],
118                         shell=(os.name == 'nt'))
119  return True
120
121
122def UpdateCurrentCheckoutIfAppropriate(magic_gclient_branch):
123  """Reset the current gclient branch if that's what we have checked out."""
124  branch = RunGit(['symbolic-ref', '-q', 'HEAD'])
125  if branch != magic_gclient_branch:
126    print "We have now updated the 'gclient' branch, but third_party/WebKit"
127    print "has some other branch ('%s') checked out." % branch
128    print "Run 'git checkout gclient' under third_party/WebKit if you want"
129    print "to switch it to the version requested by DEPS."
130    return 1
131
132  if subprocess.call(['git', 'diff-index', '--exit-code', '--shortstat',
133                      'HEAD'], shell=(os.name == 'nt')):
134    print "Resetting tree state to new revision."
135    subprocess.check_call(['git', 'reset', '--hard'], shell=(os.name == 'nt'))
136
137
138def main():
139  parser = optparse.OptionParser()
140  parser.add_option('-v', '--verbose', action='store_true')
141  parser.add_option('-r', '--revision', help="switch to desired revision")
142  parser.add_option('-t', '--tarball', help="switch to desired tarball release")
143  options, args = parser.parse_args()
144  if options.verbose:
145    logging.basicConfig(level=logging.INFO)
146  if not os.path.exists('third_party/WebKit/.git'):
147    if os.path.exists('third_party/WebKit'):
148      print "ERROR: third_party/WebKit appears to not be under git control."
149    else:
150      print "ERROR: third_party/WebKit could not be found."
151      print "Did you run this script from the right directory?"
152
153    print "See http://code.google.com/p/chromium/wiki/UsingWebKitGit for"
154    print "setup instructions."
155    return 1
156
157  if options.revision:
158    webkit_rev = options.revision
159    if options.tarball:
160      print "WARNING: --revision is given, so ignore --tarball"
161  else:
162    if options.tarball:
163      webkit_rev = GetWebKitRevFromTarball(options.tarball)
164    else:
165      webkit_rev = GetWebKitRev()
166
167  print 'Desired revision: %s.' % webkit_rev
168  os.chdir('third_party/WebKit')
169  magic_gclient_branch = GetGClientBranchName()
170  changed = UpdateGClientBranch(webkit_rev, magic_gclient_branch)
171  if changed:
172    return UpdateCurrentCheckoutIfAppropriate(magic_gclient_branch)
173  else:
174    print "Already on correct revision."
175  return 0
176
177
178if __name__ == '__main__':
179  sys.exit(main())
180