summaryrefslogtreecommitdiff
path: root/tools/sync-webkit-git.py
blob: 3c7c5484c7d4bc2795e6755d5a1b57a9a502b790 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
#!/usr/bin/env python
# Copyright (c) 2011 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.

"""Update third_party/WebKit using git.

Under the assumption third_party/WebKit is a clone of git.webkit.org,
we can use git commands to make it match the version requested by DEPS.

See http://code.google.com/p/chromium/wiki/UsingWebKitGit for details on
how to use this.
"""

import logging
import optparse
import os
import re
import subprocess
import sys
import urllib


def RunGit(command):
  """Run a git subcommand, returning its output."""
  # On Windows, use shell=True to get PATH interpretation.
  command = ['git'] + command
  logging.info(' '.join(command))
  shell = (os.name == 'nt')
  proc = subprocess.Popen(command, shell=shell, stdout=subprocess.PIPE)
  out = proc.communicate()[0].strip()
  logging.info('Returned "%s"' % out)
  return out


def GetOverrideShortBranchName():
  """Returns the user-configured override branch name, if any."""
  override_config_name = 'chromium.sync-branch'
  return RunGit(['config', '--get', override_config_name])


def GetGClientBranchName():
  """Returns the name of the magic branch that lets us know that DEPS is
  managing the update cycle."""
  # Is there an override branch specified?
  override_branch_name = GetOverrideShortBranchName()
  if not override_branch_name:
    return 'refs/heads/gclient' # No override, so return the default branch.

  # Verify that the branch from config exists.
  ref_branch = 'refs/heads/' + override_branch_name
  current_head = RunGit(['show-ref', '--hash', ref_branch])
  if current_head:
    return ref_branch

  # Inform the user about the problem and how to fix it.
  print ("The specified override branch ('%s') doesn't appear to exist." %
         override_branch_name)
  print "Please fix your git config value '%s'." % overide_config_name
  sys.exit(1)


def GetWebKitRev():
  """Extract the 'webkit_revision' variable out of DEPS."""
  locals = {'Var': lambda _: locals["vars"][_],
            'From': lambda *args: None}
  execfile('DEPS', {}, locals)
  return locals['vars']['webkit_revision']


def GetWebKitRevFromTarball(version):
  """Extract the 'webkit_revision' variable out of tarball DEPS."""
  deps_url = "http://src.chromium.org/svn/releases/" + version + "/DEPS"
  f = urllib.urlopen(deps_url)
  s = f.read()
  m = re.search('(?<=/Source@)\w+', s)
  return m.group(0)


def FindSVNRev(branch_name, target_rev):
  """Map an SVN revision to a git hash.
  Like 'git svn find-rev' but without the git-svn bits."""

  # We iterate through the commit log looking for "git-svn-id" lines,
  # which contain the SVN revision of that commit.  We can stop once
  # we've found our target (or hit a revision number lower than what
  # we're looking for, indicating not found).

  target_rev = int(target_rev)

  # regexp matching the "commit" line from the log.
  commit_re = re.compile(r'^commit ([a-f\d]{40})$')
  # regexp matching the git-svn line from the log.
  git_svn_re = re.compile(r'^\s+git-svn-id: [^@]+@(\d+) ')
  if not branch_name:
    branch_name = 'origin/master'
  cmd = ['git', 'log', '--no-color', '--first-parent', '--pretty=medium',
         branch_name]
  logging.info(' '.join(cmd))
  log = subprocess.Popen(cmd, shell=(os.name == 'nt'), stdout=subprocess.PIPE)
  # Track whether we saw a revision *later* than the one we're seeking.
  saw_later = False
  for line in log.stdout:
    match = commit_re.match(line)
    if match:
      commit = match.group(1)
      continue
    match = git_svn_re.match(line)
    if match:
      rev = int(match.group(1))
      if rev <= target_rev:
        log.stdout.close()  # Break pipe.
        if rev < target_rev:
          if not saw_later:
            return None  # Can't be sure whether this rev is ok.
          print ("WARNING: r%d not found, so using next nearest earlier r%d" %
                 (target_rev, rev))
        return commit
      else:
        saw_later = True

  print "Error: reached end of log without finding commit info."
  print "Something has likely gone horribly wrong."
  return None


def GetRemote():
  branch = GetOverrideShortBranchName()
  if not branch:
    branch = 'gclient'

  remote = RunGit(['config', '--get', 'branch.' + branch + '.remote'])
  if remote:
    return remote
  return 'origin'


def UpdateGClientBranch(branch_name, webkit_rev, magic_gclient_branch):
  """Update the magic gclient branch to point at |webkit_rev|.

  Returns: true if the branch didn't need changes."""
  target = FindSVNRev(branch_name, webkit_rev)
  if not target:
    print "r%s not available; fetching." % webkit_rev
    subprocess.check_call(['git', 'fetch', GetRemote()],
                          shell=(os.name == 'nt'))
    target = FindSVNRev(branch_name, webkit_rev)
  if not target:
    print "ERROR: Couldn't map r%s to a git revision." % webkit_rev
    sys.exit(1)

  current = RunGit(['show-ref', '--hash', magic_gclient_branch])
  if current == target:
    return False  # No change necessary.

  subprocess.check_call(['git', 'update-ref', '-m', 'gclient sync',
                         magic_gclient_branch, target],
                         shell=(os.name == 'nt'))
  return True


def UpdateCurrentCheckoutIfAppropriate(magic_gclient_branch):
  """Reset the current gclient branch if that's what we have checked out."""
  branch = RunGit(['symbolic-ref', '-q', 'HEAD'])
  if branch != magic_gclient_branch:
    print "We have now updated the 'gclient' branch, but third_party/WebKit"
    print "has some other branch ('%s') checked out." % branch
    print "Run 'git checkout gclient' under third_party/WebKit if you want"
    print "to switch it to the version requested by DEPS."
    return 1

  if subprocess.call(['git', 'diff-index', '--exit-code', '--shortstat',
                      'HEAD'], shell=(os.name == 'nt')):
    print "Resetting tree state to new revision."
    subprocess.check_call(['git', 'reset', '--hard'], shell=(os.name == 'nt'))


def main():
  parser = optparse.OptionParser()
  parser.add_option('-v', '--verbose', action='store_true')
  parser.add_option('-r', '--revision', help="switch to desired revision")
  parser.add_option('-t', '--tarball', help="switch to desired tarball release")
  parser.add_option('-b', '--branch', help="branch name that gclient generate")
  options, args = parser.parse_args()
  if options.verbose:
    logging.basicConfig(level=logging.INFO)
  if not os.path.exists('third_party/WebKit/.git'):
    if os.path.exists('third_party/WebKit'):
      print "ERROR: third_party/WebKit appears to not be under git control."
    else:
      print "ERROR: third_party/WebKit could not be found."
      print "Did you run this script from the right directory?"

    print "See http://code.google.com/p/chromium/wiki/UsingWebKitGit for"
    print "setup instructions."
    return 1

  if options.revision:
    webkit_rev = options.revision
    if options.tarball:
      print "WARNING: --revision is given, so ignore --tarball"
  else:
    if options.tarball:
      webkit_rev = GetWebKitRevFromTarball(options.tarball)
    else:
      webkit_rev = GetWebKitRev()

  print 'Desired revision: r%s.' % webkit_rev
  os.chdir('third_party/WebKit')
  magic_gclient_branch = GetGClientBranchName()
  changed = UpdateGClientBranch(options.branch, webkit_rev,
                                magic_gclient_branch)
  if changed:
    return UpdateCurrentCheckoutIfAppropriate(magic_gclient_branch)
  else:
    print "Already on correct revision."
  return 0


if __name__ == '__main__':
  sys.exit(main())