blob: 0ba47049b570377c4e090a4c9d1fc7884afb9261 [file] [log] [blame]
#!/usr/bin/env python
# Copyright (c) 2016 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.
"""Writes a file that contains a define that approximates the build date.
For unofficial builds, the build date is set to the most recent first Sunday
of a month, in UTC time.
For official builds, the build date is set to the current date (in UTC).
It is also possible to explicitly set a build date to be used.
The reason for using the first Sunday of a month for unofficial builds is that
it is a time where invalidating the build cache shouldn't have major
reprecussions (due to lower load).
import argparse
import calendar
import datetime
import os
import sys
def GetFirstSundayOfMonth(year, month):
"""Returns the first sunday of the given month of the given year."""
weeks = calendar.Calendar().monthdays2calendar(year, month)
# Return the first day in the first week that is a Sunday.
return [date_day[0] for date_day in weeks[0] if date_day[1] == 6][0]
# Validate that GetFirstSundayOfMonth works.
assert GetFirstSundayOfMonth(2016, 2) == 7
assert GetFirstSundayOfMonth(2016, 3) == 6
assert GetFirstSundayOfMonth(2000, 1) == 2
def GetBuildDate(build_type, utc_now):
"""Gets the approximate build date given the specific build type."""
day =
month = utc_now.month
year = utc_now.year
if build_type != 'official':
first_sunday = GetFirstSundayOfMonth(year, month)
# If our build is after the first Sunday, we've already refreshed our build
# cache on a quiet day, so just use that day.
# Otherwise, take the first Sunday of the previous month.
if day >= first_sunday:
day = first_sunday
month -= 1
if month == 0:
month = 12
year -= 1
day = GetFirstSundayOfMonth(year, month)
return '{:%b %d %Y}'.format(, month, day))
# Validate that GetBuildDate works.
assert GetBuildDate('default',, 2, 6)) == 'Jan 03 2016'
assert GetBuildDate('default',, 2, 7)) == 'Feb 07 2016'
assert GetBuildDate('default',, 2, 8)) == 'Feb 07 2016'
def main():
argument_parser = argparse.ArgumentParser()
argument_parser.add_argument('output_file', help='The file to write to')
argument_parser.add_argument('build_type', help='The type of build',
choices=('official', 'default'))
argument_parser.add_argument('build_date_override', nargs='?',
help='Optional override for the build date')
args = argument_parser.parse_args()
if args.build_date_override:
build_date = args.build_date_override
build_date = GetBuildDate(args.build_type, datetime.datetime.utcnow())
output = ('// Generated by //build/\n'
'#ifndef BUILD_DATE\n'
'#define BUILD_DATE "{}"\n'
'#endif // BUILD_DATE\n'.format(build_date))
current_contents = ''
if os.path.isfile(args.output_file):
with open(args.output_file, 'r') as current_file:
current_contents =
if current_contents != output:
with open(args.output_file, 'w') as output_file:
return 0
if __name__ == '__main__':