build/variables.py
author Andrew McCreight <continuation@gmail.com>
Mon, 22 Apr 2019 16:34:51 +0000
changeset 470376 3073770e06f157040f4c64951b7e8425e1ad7bbe
parent 402320 2d0766c3e7c94d7af3e40b8069aa8e3d6d4071aa
permissions -rw-r--r--
Bug 1535403 - Take indirection into account for the CC optimizations for the outer window wrapper. r=peterv Most wrapper cached C++ objects are held alive by their wrapper. The cycle collector takes advantage of this in many classes and ignores the C++ object if the wrapper is marked black. However, this is not true for the outer window's wrapper. Instead, the outer window's wrapper keeps the inner window alive. The inner window usually keeps its outer window alive, but not after it has been unlinked. For reasons I do not yet understand, the outer window's wrapper can be kept alive after the inner window it is a proxy for is unlinked. This patch fixes the cycle collector optimization for the outer window by only applying it if the outer window still has a weak reference to the inner window, which it will until the inner no longer holds the outer alive. This in turn fixes, or at least helps fix, window leaks seen intermittently when the lifetime of outer windows and docshells are tied together. The code comment is based on a review comment by peterv. Differential Revision: https://phabricator.services.mozilla.com/D27981

# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

from __future__ import print_function, unicode_literals

import os
import subprocess
import sys
from datetime import datetime

SOURCESTAMP_FILENAME = 'sourcestamp.txt'


def buildid_header(output):
    buildid = os.environ.get('MOZ_BUILD_DATE')
    if buildid and len(buildid) != 14:
        print('Ignoring invalid MOZ_BUILD_DATE: %s' % buildid, file=sys.stderr)
        buildid = None
    if not buildid:
        buildid = datetime.now().strftime('%Y%m%d%H%M%S')
    output.write("#define MOZ_BUILDID %s\n" % buildid)


def get_program_output(*command):
    try:
        with open(os.devnull) as stderr:
            return subprocess.check_output(command, stderr=stderr)
    except Exception:
        return ''


def get_hg_info(workdir):
    repo = get_program_output('hg', '-R', workdir, 'path', 'default')
    if repo:
        repo = repo.strip()
        if repo.startswith('ssh://'):
            repo = 'https://' + repo[6:]
        repo = repo.rstrip('/')

    changeset = get_hg_changeset(workdir)

    return repo, changeset


def get_hg_changeset(path):
    return get_program_output('hg', '-R', path, 'parent', '--template={node}')


def get_info_from_sourcestamp(sourcestamp_path):
    """Read the repository and changelog information from the sourcestamp
    file. This assumes that the file exists and returns the results as a list
    (either strings or None in case of error).
    """

    # Load the content of the file.
    lines = None
    with open(sourcestamp_path) as f:
        lines = f.read().splitlines()

    # Parse the repo and the changeset. The sourcestamp file is supposed to
    # contain two lines: the first is the build id and the second is the source
    # URL.
    if len(lines) != 2 or not lines[1].startswith('http'):
        # Just return if the file doesn't contain what we expect.
        return None, None

    # Return the repo and the changeset.
    return lines[1].split('/rev/')


def source_repo_header(output):
    # We allow the source repo and changeset to be specified via the
    # environment (see configure)
    import buildconfig
    repo = buildconfig.substs.get('MOZ_SOURCE_REPO')
    changeset = buildconfig.substs.get('MOZ_SOURCE_CHANGESET')
    source = ''

    if not repo:
        sourcestamp_path = os.path.join(
            buildconfig.topsrcdir, SOURCESTAMP_FILENAME)
        if os.path.exists(os.path.join(buildconfig.topsrcdir, '.hg')):
            repo, changeset = get_hg_info(buildconfig.topsrcdir)
        elif os.path.exists(sourcestamp_path):
            repo, changeset = get_info_from_sourcestamp(sourcestamp_path)
    elif not changeset:
        changeset = get_hg_changeset(buildconfig.topsrcdir)
        if not changeset:
            raise Exception('could not resolve changeset; '
                            'try setting MOZ_SOURCE_CHANGESET')

    if changeset:
        output.write('#define MOZ_SOURCE_STAMP %s\n' % changeset)

    if repo and buildconfig.substs.get('MOZ_INCLUDE_SOURCE_INFO'):
        source = '%s/rev/%s' % (repo, changeset)
        output.write('#define MOZ_SOURCE_REPO %s\n' % repo)
        output.write('#define MOZ_SOURCE_URL %s\n' % source)


def main(args):
    if (len(args)):
        func = globals().get(args[0])
        if func:
            return func(sys.stdout, *args[1:])


if __name__ == '__main__':
    sys.exit(main(sys.argv[1:]))