1#!/usr/bin/env python3 2# Copyright 2012 The Chromium Authors 3# Use of this source code is governed by a BSD-style license that can be 4# found in the LICENSE file. 5 6""" 7lastchange.py -- Chromium revision fetching utility. 8""" 9 10import argparse 11import collections 12import datetime 13import logging 14import os 15import subprocess 16import sys 17 18VersionInfo = collections.namedtuple("VersionInfo", 19 ("revision_id", "revision", "timestamp")) 20 21class GitError(Exception): 22 pass 23 24# This function exists for compatibility with logic outside this 25# repository that uses this file as a library. 26# TODO(eliribble) remove this function after it has been ported into 27# the repositories that depend on it 28def RunGitCommand(directory, command): 29 """ 30 Launches git subcommand. 31 32 Errors are swallowed. 33 34 Returns: 35 A process object or None. 36 """ 37 command = ['git'] + command 38 # Force shell usage under cygwin. This is a workaround for 39 # mysterious loss of cwd while invoking cygwin's git. 40 # We can't just pass shell=True to Popen, as under win32 this will 41 # cause CMD to be used, while we explicitly want a cygwin shell. 42 if sys.platform == 'cygwin': 43 command = ['sh', '-c', ' '.join(command)] 44 try: 45 proc = subprocess.Popen(command, 46 stdout=subprocess.PIPE, 47 stderr=subprocess.PIPE, 48 cwd=directory, 49 shell=(sys.platform=='win32')) 50 return proc 51 except OSError as e: 52 logging.error('Command %r failed: %s' % (' '.join(command), e)) 53 return None 54 55 56def _RunGitCommand(directory, command): 57 """Launches git subcommand. 58 59 Returns: 60 The stripped stdout of the git command. 61 Raises: 62 GitError on failure, including a nonzero return code. 63 """ 64 command = ['git'] + command 65 # Force shell usage under cygwin. This is a workaround for 66 # mysterious loss of cwd while invoking cygwin's git. 67 # We can't just pass shell=True to Popen, as under win32 this will 68 # cause CMD to be used, while we explicitly want a cygwin shell. 69 if sys.platform == 'cygwin': 70 command = ['sh', '-c', ' '.join(command)] 71 try: 72 logging.info("Executing '%s' in %s", ' '.join(command), directory) 73 proc = subprocess.Popen(command, 74 stdout=subprocess.PIPE, 75 stderr=subprocess.PIPE, 76 cwd=directory, 77 shell=(sys.platform=='win32')) 78 stdout, stderr = tuple(x.decode(encoding='utf_8') 79 for x in proc.communicate()) 80 stdout = stdout.strip() 81 stderr = stderr.strip() 82 logging.debug("returncode: %d", proc.returncode) 83 logging.debug("stdout: %s", stdout) 84 logging.debug("stderr: %s", stderr) 85 if proc.returncode != 0 or not stdout: 86 raise GitError(( 87 "Git command '{}' in {} failed: " 88 "rc={}, stdout='{}' stderr='{}'").format( 89 " ".join(command), directory, proc.returncode, stdout, stderr)) 90 return stdout 91 except OSError as e: 92 raise GitError("Git command 'git {}' in {} failed: {}".format( 93 " ".join(command), directory, e)) 94 95 96def GetMergeBase(directory, ref): 97 """ 98 Return the merge-base of HEAD and ref. 99 100 Args: 101 directory: The directory containing the .git directory. 102 ref: The ref to use to find the merge base. 103 Returns: 104 The git commit SHA of the merge-base as a string. 105 """ 106 logging.debug("Calculating merge base between HEAD and %s in %s", 107 ref, directory) 108 command = ['merge-base', 'HEAD', ref] 109 return _RunGitCommand(directory, command) 110 111 112def FetchGitRevision(directory, commit_filter, start_commit="HEAD"): 113 """ 114 Fetch the Git hash (and Cr-Commit-Position if any) for a given directory. 115 116 Args: 117 directory: The directory containing the .git directory. 118 commit_filter: A filter to supply to grep to filter commits 119 start_commit: A commit identifier. The result of this function 120 will be limited to only consider commits before the provided 121 commit. 122 Returns: 123 A VersionInfo object. On error all values will be 0. 124 """ 125 hash_ = '' 126 127 git_args = ['log', '-1', '--format=%H %ct'] 128 if commit_filter is not None: 129 git_args.append('--grep=' + commit_filter) 130 131 git_args.append(start_commit) 132 133 output = _RunGitCommand(directory, git_args) 134 hash_, commit_timestamp = output.split() 135 if not hash_: 136 return VersionInfo('0', '0', 0) 137 138 revision = hash_ 139 output = _RunGitCommand(directory, ['cat-file', 'commit', hash_]) 140 for line in reversed(output.splitlines()): 141 if line.startswith('Cr-Commit-Position:'): 142 pos = line.rsplit()[-1].strip() 143 logging.debug("Found Cr-Commit-Position '%s'", pos) 144 revision = "{}-{}".format(hash_, pos) 145 break 146 return VersionInfo(hash_, revision, int(commit_timestamp)) 147 148 149def GetHeaderGuard(path): 150 """ 151 Returns the header #define guard for the given file path. 152 This treats everything after the last instance of "src/" as being a 153 relevant part of the guard. If there is no "src/", then the entire path 154 is used. 155 """ 156 src_index = path.rfind('src/') 157 if src_index != -1: 158 guard = path[src_index + 4:] 159 else: 160 guard = path 161 guard = guard.upper() 162 return guard.replace('/', '_').replace('.', '_').replace('\\', '_') + '_' 163 164 165def GetHeaderContents(path, define, version): 166 """ 167 Returns what the contents of the header file should be that indicate the given 168 revision. 169 """ 170 header_guard = GetHeaderGuard(path) 171 172 header_contents = """/* Generated by lastchange.py, do not edit.*/ 173 174#ifndef %(header_guard)s 175#define %(header_guard)s 176 177#define %(define)s "%(version)s" 178 179#endif // %(header_guard)s 180""" 181 header_contents = header_contents % { 'header_guard': header_guard, 182 'define': define, 183 'version': version } 184 return header_contents 185 186 187def GetGitTopDirectory(source_dir): 188 """Get the top git directory - the directory that contains the .git directory. 189 190 Args: 191 source_dir: The directory to search. 192 Returns: 193 The output of "git rev-parse --show-toplevel" as a string 194 """ 195 return _RunGitCommand(source_dir, ['rev-parse', '--show-toplevel']) 196 197 198def WriteIfChanged(file_name, contents): 199 """ 200 Writes the specified contents to the specified file_name 201 iff the contents are different than the current contents. 202 Returns if new data was written. 203 """ 204 try: 205 old_contents = open(file_name, 'r').read() 206 except EnvironmentError: 207 pass 208 else: 209 if contents == old_contents: 210 return False 211 os.unlink(file_name) 212 open(file_name, 'w').write(contents) 213 return True 214 215 216def main(argv=None): 217 if argv is None: 218 argv = sys.argv 219 220 parser = argparse.ArgumentParser(usage="lastchange.py [options]") 221 parser.add_argument("-m", "--version-macro", 222 help=("Name of C #define when using --header. Defaults to " 223 "LAST_CHANGE.")) 224 parser.add_argument("-o", 225 "--output", 226 metavar="FILE", 227 help=("Write last change to FILE. " 228 "Can be combined with other file-output-related " 229 "options to write multiple files.")) 230 parser.add_argument("--header", 231 metavar="FILE", 232 help=("Write last change to FILE as a C/C++ header. " 233 "Can be combined with other file-output-related " 234 "options to write multiple files.")) 235 parser.add_argument("--revision", 236 metavar="FILE", 237 help=("Write last change to FILE as a one-line revision. " 238 "Can be combined with other file-output-related " 239 "options to write multiple files.")) 240 parser.add_argument("--merge-base-ref", 241 default=None, 242 help=("Only consider changes since the merge " 243 "base between HEAD and the provided ref")) 244 parser.add_argument("--revision-id-only", action='store_true', 245 help=("Output the revision as a VCS revision ID only (in " 246 "Git, a 40-character commit hash, excluding the " 247 "Cr-Commit-Position).")) 248 parser.add_argument("--revision-id-prefix", 249 metavar="PREFIX", 250 help=("Adds a string prefix to the VCS revision ID.")) 251 parser.add_argument("--print-only", action="store_true", 252 help=("Just print the revision string. Overrides any " 253 "file-output-related options.")) 254 parser.add_argument("-s", "--source-dir", metavar="DIR", 255 help="Use repository in the given directory.") 256 parser.add_argument("--filter", metavar="REGEX", 257 help=("Only use log entries where the commit message " 258 "matches the supplied filter regex. Defaults to " 259 "'^Change-Id:' to suppress local commits."), 260 default='^Change-Id:') 261 262 args, extras = parser.parse_known_args(argv[1:]) 263 264 logging.basicConfig(level=logging.WARNING) 265 266 out_file = args.output 267 header = args.header 268 revision = args.revision 269 commit_filter=args.filter 270 271 while len(extras) and out_file is None: 272 if out_file is None: 273 out_file = extras.pop(0) 274 if extras: 275 sys.stderr.write('Unexpected arguments: %r\n\n' % extras) 276 parser.print_help() 277 sys.exit(2) 278 279 source_dir = args.source_dir or os.path.dirname(os.path.abspath(__file__)) 280 281 git_top_dir = None 282 try: 283 git_top_dir = GetGitTopDirectory(source_dir) 284 except GitError as e: 285 logging.warning("Failed to get git top directory from '%s': %s", source_dir, 286 e) 287 288 merge_base_sha = 'HEAD' 289 if git_top_dir and args.merge_base_ref: 290 try: 291 merge_base_sha = GetMergeBase(git_top_dir, args.merge_base_ref) 292 except GitError as e: 293 logging.error("You requested a --merge-base-ref value of '%s' but no " 294 "merge base could be found between it and HEAD. Git " 295 "reports: %s", args.merge_base_ref, e) 296 return 3 297 298 version_info = None 299 if git_top_dir: 300 try: 301 version_info = FetchGitRevision(git_top_dir, commit_filter, 302 merge_base_sha) 303 except GitError as e: 304 logging.error("Failed to get version info: %s", e) 305 306 if not version_info: 307 logging.warning( 308 "Falling back to a version of 0.0.0 to allow script to " 309 "finish. This is normal if you are bootstrapping a new environment " 310 "or do not have a git repository for any other reason. If not, this " 311 "could represent a serious error.") 312 # Use a dummy revision that has the same length as a Git commit hash, 313 # same as what we use in build/util/LASTCHANGE.dummy. 314 version_info = VersionInfo('0' * 40, '0' * 40, 0) 315 316 revision_string = version_info.revision 317 if args.revision_id_only: 318 revision_string = version_info.revision_id 319 320 if args.revision_id_prefix: 321 revision_string = args.revision_id_prefix + revision_string 322 323 if args.print_only: 324 print(revision_string) 325 else: 326 lastchange_year = datetime.datetime.fromtimestamp( 327 version_info.timestamp, datetime.timezone.utc).year 328 contents_lines = [ 329 "LASTCHANGE=%s" % revision_string, 330 "LASTCHANGE_YEAR=%s" % lastchange_year, 331 ] 332 contents = '\n'.join(contents_lines) + '\n' 333 if not out_file and not header and not revision: 334 sys.stdout.write(contents) 335 else: 336 if out_file: 337 committime_file = out_file + '.committime' 338 out_changed = WriteIfChanged(out_file, contents) 339 if out_changed or not os.path.exists(committime_file): 340 with open(committime_file, 'w') as timefile: 341 timefile.write(str(version_info.timestamp)) 342 if header: 343 WriteIfChanged(header, 344 GetHeaderContents(header, args.version_macro, 345 revision_string)) 346 if revision: 347 WriteIfChanged(revision, revision_string) 348 349 return 0 350 351 352if __name__ == '__main__': 353 sys.exit(main()) 354