build/util/lastchange.py

   1 #!/usr/bin/env python
   2 # Copyright (c) 2012 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 """
   7 lastchange.py -- Chromium revision fetching utility.
   8 """
   9
  10 import re
  11 import optparse
  12 import os
  13 import subprocess
  14 import sys
  15
  16 _GIT_SVN_ID_REGEX = re.compile(r'.*git-svn-id:\s*([^@]*)@([0-9]+)', re.DOTALL)
  17
  18 class VersionInfo(object):
  19   def __init__(self, url, revision):
  20     self.url = url
  21     self.revision = revision
  22
  23
  24 def FetchSVNRevision(directory, svn_url_regex):
  25   """
  26   Fetch the Subversion branch and revision for a given directory.
  27
  28   Errors are swallowed.
  29
  30   Returns:
  31     A VersionInfo object or None on error.
  32   """
  33   try:
  34     proc = subprocess.Popen(['svn', 'info'],
  35                             stdout=subprocess.PIPE,
  36                             stderr=subprocess.PIPE,
  37                             cwd=directory,
  38                             shell=(sys.platform=='win32'))
  39   except OSError:
  40     # command is apparently either not installed or not executable.
  41     return None
  42   if not proc:
  43     return None
  44
  45   attrs = {}
  46   for line in proc.stdout:
  47     line = line.strip()
  48     if not line:
  49       continue
  50     key, val = line.split(': ', 1)
  51     attrs[key] = val
  52
  53   try:
  54     match = svn_url_regex.search(attrs['URL'])
  55     if match:
  56       url = match.group(2)
  57     else:
  58       url = ''
  59     revision = attrs['Revision']
  60   except KeyError:
  61     return None
  62
  63   return VersionInfo(url, revision)
  64
  65
  66 def RunGitCommand(directory, command):
  67   """
  68   Launches git subcommand.
  69
  70   Errors are swallowed.
  71
  72   Returns:
  73     A process object or None.
  74   """
  75   command = ['git'] + command
  76   # Force shell usage under cygwin. This is a workaround for
  77   # mysterious loss of cwd while invoking cygwin's git.
  78   # We can't just pass shell=True to Popen, as under win32 this will
  79   # cause CMD to be used, while we explicitly want a cygwin shell.
  80   if sys.platform == 'cygwin':
  81     command = ['sh', '-c', ' '.join(command)]
  82   try:
  83     proc = subprocess.Popen(command,
  84                             stdout=subprocess.PIPE,
  85                             stderr=subprocess.PIPE,
  86                             cwd=directory,
  87                             shell=(sys.platform=='win32'))
  88     return proc
  89   except OSError:
  90     return None
  91
  92
  93 def FetchGitRevision(directory):
  94   """
  95   Fetch the Git hash for a given directory.
  96
  97   Errors are swallowed.
  98
  99   Returns:
 100     A VersionInfo object or None on error.
 101   """
 102   # TODO(agable): Re-add the commit position after the lastchange value can
 103   # accept strings longer than 64 characters. See crbug.com/406783.
 104   hsh = ''
 105   proc = RunGitCommand(directory, ['rev-parse', 'HEAD'])
 106   if proc:
 107     output = proc.communicate()[0].strip()
 108     if proc.returncode == 0 and output:
 109       hsh = output
 110   if not hsh:
 111     return None
 112   # TODO(agable): Figure out a way to use the full hash instead of just a
 113   # 12-character short hash. See crbug.com/406783.
 114   return VersionInfo('git', hsh[:12])
 115
 116
 117 def FetchGitSVNURLAndRevision(directory, svn_url_regex):
 118   """
 119   Fetch the Subversion URL and revision through Git.
 120
 121   Errors are swallowed.
 122
 123   Returns:
 124     A tuple containing the Subversion URL and revision.
 125   """
 126   proc = RunGitCommand(directory, ['log', '-1', '--format=%b'])
 127   if proc:
 128     output = proc.communicate()[0].strip()
 129     if proc.returncode == 0 and output:
 130       # Extract the latest SVN revision and the SVN URL.
 131       # The target line is the last "git-svn-id: ..." line like this:
 132       # git-svn-id: svn://svn.chromium.org/chrome/trunk/src@85528 0039d316....
 133       match = _GIT_SVN_ID_REGEX.search(output)
 134       if match:
 135         revision = match.group(2)
 136         url_match = svn_url_regex.search(match.group(1))
 137         if url_match:
 138           url = url_match.group(2)
 139         else:
 140           url = ''
 141         return url, revision
 142   return None, None
 143
 144
 145 def FetchGitSVNRevision(directory, svn_url_regex):
 146   """
 147   Fetch the Git-SVN identifier for the local tree.
 148
 149   Errors are swallowed.
 150   """
 151   url, revision = FetchGitSVNURLAndRevision(directory, svn_url_regex)
 152   if url and revision:
 153     return VersionInfo(url, revision)
 154   return None
 155
 156
 157 def FetchVersionInfo(default_lastchange, directory=None,
 158                      directory_regex_prior_to_src_url='chrome|blink|svn'):
 159   """
 160   Returns the last change (in the form of a branch, revision tuple),
 161   from some appropriate revision control system.
 162   """
 163   svn_url_regex = re.compile(
 164       r'.*/(' + directory_regex_prior_to_src_url + r')(/.*)')
 165
 166   version_info = (FetchSVNRevision(directory, svn_url_regex) or
 167                   FetchGitSVNRevision(directory, svn_url_regex) or
 168                   FetchGitRevision(directory))
 169   if not version_info:
 170     if default_lastchange and os.path.exists(default_lastchange):
 171       revision = open(default_lastchange, 'r').read().strip()
 172       version_info = VersionInfo(None, revision)
 173     else:
 174       version_info = VersionInfo(None, None)
 175   return version_info
 176
 177 def GetHeaderGuard(path):
 178   """
 179   Returns the header #define guard for the given file path.
 180   This treats everything after the last instance of "src/" as being a
 181   relevant part of the guard. If there is no "src/", then the entire path
 182   is used.
 183   """
 184   src_index = path.rfind('src/')
 185   if src_index != -1:
 186     guard = path[src_index + 4:]
 187   else:
 188     guard = path
 189   guard = guard.upper()
 190   return guard.replace('/', '_').replace('.', '_').replace('\\', '_') + '_'
 191
 192 def GetHeaderContents(path, define, version):
 193   """
 194   Returns what the contents of the header file should be that indicate the given
 195   revision. Note that the #define is specified as a string, even though it's
 196   currently always a SVN revision number, in case we need to move to git hashes.
 197   """
 198   header_guard = GetHeaderGuard(path)
 199
 200   header_contents = """/* Generated by lastchange.py, do not edit.*/
 201
 202 #ifndef %(header_guard)s
 203 #define %(header_guard)s
 204
 205 #define %(define)s "%(version)s"
 206
 207 #endif  // %(header_guard)s
 208 """
 209   header_contents = header_contents % { 'header_guard': header_guard,
 210                                         'define': define,
 211                                         'version': version }
 212   return header_contents
 213
 214 def WriteIfChanged(file_name, contents):
 215   """
 216   Writes the specified contents to the specified file_name
 217   iff the contents are different than the current contents.
 218   """
 219   try:
 220     old_contents = open(file_name, 'r').read()
 221   except EnvironmentError:
 222     pass
 223   else:
 224     if contents == old_contents:
 225       return
 226     os.unlink(file_name)
 227   open(file_name, 'w').write(contents)
 228
 229
 230 def main(argv=None):
 231   if argv is None:
 232     argv = sys.argv
 233
 234   parser = optparse.OptionParser(usage="lastchange.py [options]")
 235   parser.add_option("-d", "--default-lastchange", metavar="FILE",
 236                     help="Default last change input FILE.")
 237   parser.add_option("-m", "--version-macro",
 238                     help="Name of C #define when using --header. Defaults to " +
 239                     "LAST_CHANGE.",
 240                     default="LAST_CHANGE")
 241   parser.add_option("-o", "--output", metavar="FILE",
 242                     help="Write last change to FILE. " +
 243                     "Can be combined with --header to write both files.")
 244   parser.add_option("", "--header", metavar="FILE",
 245                     help="Write last change to FILE as a C/C++ header. " +
 246                     "Can be combined with --output to write both files.")
 247   parser.add_option("--revision-only", action='store_true',
 248                     help="Just print the SVN revision number. Overrides any " +
 249                     "file-output-related options.")
 250   parser.add_option("-s", "--source-dir", metavar="DIR",
 251                     help="Use repository in the given directory.")
 252   opts, args = parser.parse_args(argv[1:])
 253
 254   out_file = opts.output
 255   header = opts.header
 256
 257   while len(args) and out_file is None:
 258     if out_file is None:
 259       out_file = args.pop(0)
 260   if args:
 261     sys.stderr.write('Unexpected arguments: %r\n\n' % args)
 262     parser.print_help()
 263     sys.exit(2)
 264
 265   if opts.source_dir:
 266     src_dir = opts.source_dir
 267   else:
 268     src_dir = os.path.dirname(os.path.abspath(__file__))
 269
 270   version_info = FetchVersionInfo(opts.default_lastchange, src_dir)
 271
 272   if version_info.revision == None:
 273     version_info.revision = '0'
 274
 275   if opts.revision_only:
 276     print version_info.revision
 277   else:
 278     contents = "LASTCHANGE=%s\n" % version_info.revision
 279     if not out_file and not opts.header:
 280       sys.stdout.write(contents)
 281     else:
 282       if out_file:
 283         WriteIfChanged(out_file, contents)
 284       if header:
 285         WriteIfChanged(header,
 286                        GetHeaderContents(header, opts.version_macro,
 287                                          version_info.revision))
 288
 289   return 0
 290
 291
 292 if __name__ == '__main__':
 293   sys.exit(main())