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#!/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 --header to write both files."))
parser.add_argument("--header", metavar="FILE",
help=("Write last change to FILE as a C/C++ header. "
"Can be combined with --output to write both 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
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 args.header:
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))
return 0
if __name__ == '__main__':
sys.exit(main())