#!/usr/bin/env python # Copyright (c) 2012 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. """ lastchange.py -- Chromium revision fetching utility. """ from __future__ import print_function import argparse import collections import datetime import logging import os import subprocess import sys VersionInfo = collections.namedtuple("VersionInfo", ("revision_id", "revision", "timestamp")) class GitError(Exception): pass # This function exists for compatibility with logic outside this # repository that uses this file as a library. # TODO(eliribble) remove this function after it has been ported into # the repositories that depend on it def RunGitCommand(directory, command): """ Launches git subcommand. Errors are swallowed. Returns: A process object or None. """ command = ['git'] + command # Force shell usage under cygwin. This is a workaround for # mysterious loss of cwd while invoking cygwin's git. # We can't just pass shell=True to Popen, as under win32 this will # cause CMD to be used, while we explicitly want a cygwin shell. if sys.platform == 'cygwin': command = ['sh', '-c', ' '.join(command)] try: proc = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.PIPE, cwd=directory, shell=(sys.platform=='win32')) return proc except OSError as e: logging.error('Command %r failed: %s' % (' '.join(command), e)) return None def _RunGitCommand(directory, command): """Launches git subcommand. Returns: The stripped stdout of the git command. Raises: GitError on failure, including a nonzero return code. """ command = ['git'] + command # Force shell usage under cygwin. This is a workaround for # mysterious loss of cwd while invoking cygwin's git. # We can't just pass shell=True to Popen, as under win32 this will # cause CMD to be used, while we explicitly want a cygwin shell. if sys.platform == 'cygwin': command = ['sh', '-c', ' '.join(command)] try: logging.info("Executing '%s' in %s", ' '.join(command), directory) proc = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.PIPE, cwd=directory, shell=(sys.platform=='win32')) stdout, stderr = tuple(x.decode(encoding='utf_8') for x in proc.communicate()) stdout = stdout.strip() logging.debug("returncode: %d", proc.returncode) logging.debug("stdout: %s", stdout) logging.debug("stderr: %s", stderr) if proc.returncode != 0 or not stdout: raise GitError(( "Git command '{}' in {} failed: " "rc={}, stdout='{}' stderr='{}'").format( " ".join(command), directory, proc.returncode, stdout, stderr)) return stdout except OSError as e: raise GitError("Git command 'git {}' in {} failed: {}".format( " ".join(command), directory, e)) def GetMergeBase(directory, ref): """ Return the merge-base of HEAD and ref. Args: directory: The directory containing the .git directory. ref: The ref to use to find the merge base. Returns: The git commit SHA of the merge-base as a string. """ logging.debug("Calculating merge base between HEAD and %s in %s", ref, directory) command = ['merge-base', 'HEAD', ref] return _RunGitCommand(directory, command) def FetchGitRevision(directory, commit_filter, start_commit="HEAD"): """ Fetch the Git hash (and Cr-Commit-Position if any) for a given directory. Args: directory: The directory containing the .git directory. commit_filter: A filter to supply to grep to filter commits start_commit: A commit identifier. The result of this function will be limited to only consider commits before the provided commit. Returns: A VersionInfo object. On error all values will be 0. """ hash_ = '' git_args = ['log', '-1', '--format=%H %ct'] if commit_filter is not None: git_args.append('--grep=' + commit_filter) git_args.append(start_commit) output = _RunGitCommand(directory, git_args) hash_, commit_timestamp = output.split() if not hash_: return VersionInfo('0', '0', 0) revision = hash_ output = _RunGitCommand(directory, ['cat-file', 'commit', hash_]) for line in reversed(output.splitlines()): if line.startswith('Cr-Commit-Position:'): pos = line.rsplit()[-1].strip() logging.debug("Found Cr-Commit-Position '%s'", pos) revision = "{}-{}".format(hash_, pos) break return VersionInfo(hash_, revision, int(commit_timestamp)) def GetHeaderGuard(path): """ Returns the header #define guard for the given file path. This treats everything after the last instance of "src/" as being a relevant part of the guard. If there is no "src/", then the entire path is used. """ src_index = path.rfind('src/') if src_index != -1: guard = path[src_index + 4:] else: guard = path guard = guard.upper() return guard.replace('/', '_').replace('.', '_').replace('\\', '_') + '_' def GetHeaderContents(path, define, version): """ Returns what the contents of the header file should be that indicate the given revision. """ header_guard = GetHeaderGuard(path) header_contents = """/* Generated by lastchange.py, do not edit.*/ #ifndef %(header_guard)s #define %(header_guard)s #define %(define)s "%(version)s" #endif // %(header_guard)s """ header_contents = header_contents % { 'header_guard': header_guard, 'define': define, 'version': version } return header_contents def GetGitTopDirectory(source_dir): """Get the top git directory - the directory that contains the .git directory. Args: source_dir: The directory to search. Returns: The output of "git rev-parse --show-toplevel" as a string """ return _RunGitCommand(source_dir, ['rev-parse', '--show-toplevel']) def WriteIfChanged(file_name, contents): """ Writes the specified contents to the specified file_name iff the contents are different than the current contents. Returns if new data was written. """ try: old_contents = open(file_name, 'r').read() except EnvironmentError: pass else: if contents == old_contents: return False os.unlink(file_name) open(file_name, 'w').write(contents) return True def main(argv=None): if argv is None: argv = sys.argv parser = argparse.ArgumentParser(usage="lastchange.py [options]") parser.add_argument("-m", "--version-macro", help=("Name of C #define when using --header. Defaults to " "LAST_CHANGE.")) parser.add_argument("-o", "--output", metavar="FILE", help=("Write last change to FILE. " "Can be combined with other file-output-related " "options to write multiple files.")) parser.add_argument("--header", metavar="FILE", help=("Write last change to FILE as a C/C++ header. " "Can be combined with other file-output-related " "options to write multiple files.")) parser.add_argument("--revision", metavar="FILE", help=("Write last change to FILE as a one-line revision. " "Can be combined with other file-output-related " "options to write multiple files.")) parser.add_argument("--merge-base-ref", default=None, help=("Only consider changes since the merge " "base between HEAD and the provided ref")) parser.add_argument("--revision-id-only", action='store_true', help=("Output the revision as a VCS revision ID only (in " "Git, a 40-character commit hash, excluding the " "Cr-Commit-Position).")) parser.add_argument("--revision-id-prefix", metavar="PREFIX", help=("Adds a string prefix to the VCS revision ID.")) parser.add_argument("--print-only", action="store_true", help=("Just print the revision string. Overrides any " "file-output-related options.")) parser.add_argument("-s", "--source-dir", metavar="DIR", help="Use repository in the given directory.") parser.add_argument("--filter", metavar="REGEX", help=("Only use log entries where the commit message " "matches the supplied filter regex. Defaults to " "'^Change-Id:' to suppress local commits."), default='^Change-Id:') args, extras = parser.parse_known_args(argv[1:]) logging.basicConfig(level=logging.WARNING) out_file = args.output header = args.header revision = args.revision commit_filter=args.filter while len(extras) and out_file is None: if out_file is None: out_file = extras.pop(0) if extras: sys.stderr.write('Unexpected arguments: %r\n\n' % extras) parser.print_help() sys.exit(2) source_dir = args.source_dir or os.path.dirname(os.path.abspath(__file__)) try: git_top_dir = GetGitTopDirectory(source_dir) except GitError as e: logging.error("Failed to get git top directory from '%s': %s", source_dir, e) return 2 if args.merge_base_ref: try: merge_base_sha = GetMergeBase(git_top_dir, args.merge_base_ref) except GitError as e: logging.error("You requested a --merge-base-ref value of '%s' but no " "merge base could be found between it and HEAD. Git " "reports: %s", args.merge_base_ref, e) return 3 else: merge_base_sha = 'HEAD' try: version_info = FetchGitRevision(git_top_dir, commit_filter, merge_base_sha) except GitError as e: logging.error("Failed to get version info: %s", e) logging.info(("Falling back to a version of 0.0.0 to allow script to " "finish. This is normal if you are bootstrapping a new environment " "or do not have a git repository for any other reason. If not, this " "could represent a serious error.")) version_info = VersionInfo('0', '0', 0) revision_string = version_info.revision if args.revision_id_only: revision_string = version_info.revision_id if args.revision_id_prefix: revision_string = args.revision_id_prefix + revision_string if args.print_only: print(revision_string) else: lastchange_year = datetime.datetime.utcfromtimestamp( version_info.timestamp).year contents_lines = [ "LASTCHANGE=%s" % revision_string, "LASTCHANGE_YEAR=%s" % lastchange_year, ] contents = '\n'.join(contents_lines) + '\n' if not out_file and not header and not revision: sys.stdout.write(contents) else: if out_file: committime_file = out_file + '.committime' out_changed = WriteIfChanged(out_file, contents) if out_changed or not os.path.exists(committime_file): with open(committime_file, 'w') as timefile: timefile.write(str(version_info.timestamp)) if header: WriteIfChanged(header, GetHeaderContents(header, args.version_macro, revision_string)) if revision: WriteIfChanged(revision, revision_string) return 0 if __name__ == '__main__': sys.exit(main())