author Jim Blandy <>
Tue, 12 Feb 2019 08:16:16 +0000
changeset 458932 414b2c238839c321dee78a9d927c968f1e52ae79
parent 454195 ab27c46876ddb7ef3a1c99d8c2297fa7d0039e2d
child 460007 effd6611eaccae8fcc3572286a229f9efe96ce7d
permissions -rw-r--r--
Bug 1145201: Replace EnqueuePromiseJobCallback and GetIncumbentGlobalCallback with new JobQueue abstract base class. r=arai,smaug While the behavior of ECMAScript Promises and their associated job queue is covered by the ECMAScript standard, the HTML specification amends that with additional behavior the web platform requires. To support this, SpiderMonkey provides hooks the embedding can set to replace SpiderMonkey's queue with its own implementation. At present, these hooks are C-style function-pointer-and-void-pointer pairs, which are awkward to handle and mistake-prone, as passing a function the wrong void* is not a type error. Later patches in this series must add new hooks, making a bad situation worse. A C++ abstract base class is a well-typed alternative. This introduces a new `JS::JobQueue` abstract class, and adapts SpiderMonkey's internal job queue and Gecko's customization to use it. `GetIncumbentGlobalCallback` and `EnqueuePromiseJobCallback` become virtual methods. Within SpiderMonkey, the patch gathers the various fields of JSContext that implement the internal queue into their own type, js::InternalJobQueue. Various jsfriendapi functions become veneers for calls to methods specific to the derived class. The InternalJobQueue type itself remains private to SpiderMonkey, as it uses types like TraceableFifo, derived from Fifo, that are not part of SpiderMonkey's public API. Within Gecko, CycleCollectedJSContext acquires JS::JobQueue as a private base class, and a few static methods are cleaned up nicely. There are a few other hooks defined in js/public/Promise.h that might make sense to turn into virtual methods on JobQueue. For example, DispatchToEventLoopCallback, used for resolving promises of results from off-main-thread tasks, is probably necessarily connected to the JobQueue implementation in use, so it might not be sensible to set one without the other. But it was left unchanged to reduce this patch's size. Differential Revision:

# 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

from __future__ import print_function, unicode_literals

import codecs
import itertools
import logging
import os
import sys
import textwrap

base_dir = os.path.abspath(os.path.dirname(__file__))
sys.path.insert(0, os.path.join(base_dir, 'python', 'mozbuild'))
from mozbuild.configure import ConfigureSandbox
from mozbuild.pythonutil import iter_modules_in_path
from mozbuild.backend.configenvironment import PartialConfigEnvironment
from mozbuild.util import (
import mozpack.path as mozpath

def main(argv):
    config = {}
    sandbox = ConfigureSandbox(config, os.environ, argv), 'moz.configure'))

    if sandbox._help:
        return 0

    return config_status(config)

def config_status(config):
    # Sanitize config data to feed config.status
    # Ideally, all the backend and frontend code would handle the booleans, but
    # there are so many things involved, that it's easier to keep config.status
    # untouched for now.
    def sanitized_bools(v):
        if v is True:
            return '1'
        if v is False:
            return ''
        return v

    sanitized_config = {}
    sanitized_config['substs'] = {
        k: sanitized_bools(v) for k, v in config.iteritems()
        if k not in ('DEFINES', 'non_global_defines', 'TOPSRCDIR', 'TOPOBJDIR',
    sanitized_config['defines'] = {
        k: sanitized_bools(v) for k, v in config['DEFINES'].iteritems()
    sanitized_config['non_global_defines'] = config['non_global_defines']
    sanitized_config['topsrcdir'] = config['TOPSRCDIR']
    sanitized_config['topobjdir'] = config['TOPOBJDIR']
    sanitized_config['mozconfig'] = config.get('MOZCONFIG')

    # Create config.status. Eventually, we'll want to just do the work it does
    # here, when we're able to skip configure tests/use cached results/not rely
    # on autoconf.
    logging.getLogger('moz.configure').info('Creating config.status')
    encoding = 'mbcs' if sys.platform == 'win32' else 'utf-8'
    with'config.status', 'w', encoding) as fh:
            # coding=%(encoding)s
            from __future__ import unicode_literals
            from mozbuild.util import encode
            encoding = '%(encoding)s'
        ''') % {'python': config['PYTHON'], 'encoding': encoding})
        # A lot of the build backend code is currently expecting byte
        # strings and breaks in subtle ways with unicode strings. (bug 1296508)
        for k, v in sanitized_config.iteritems():
            fh.write('%s = encode(%s, encoding)\n' % (k, indented_repr(v)))
        fh.write("__all__ = ['topobjdir', 'topsrcdir', 'defines', "
                 "'non_global_defines', 'substs', 'mozconfig']")

        if config.get('MOZ_BUILD_APP') != 'js' or config.get('JS_STANDALONE'):
                if __name__ == '__main__':
                    from mozbuild.util import patch_main
                    from mozbuild.config_status import config_status
                    args = dict([(name, globals()[name]) for name in __all__])

    partial_config = PartialConfigEnvironment(config['TOPOBJDIR'])

    # Write out a file so the build backend knows to re-run configure when
    # relevant Python changes.
    with open('', 'w') as fh:
        for f in itertools.chain(config['CONFIG_STATUS_DEPS'],
            fh.write('%s\n' % mozpath.normpath(f))

    # Other things than us are going to run this file, so we need to give it
    # executable permissions.
    os.chmod('config.status', 0o755)
    if config.get('MOZ_BUILD_APP') != 'js' or config.get('JS_STANDALONE'):
        from mozbuild.config_status import config_status

        # Some values in sanitized_config also have more complex types, such as
        # EnumString, which using when calling config_status would currently
        # break the build, as well as making it inconsistent with re-running
        # config.status. Fortunately, EnumString derives from unicode, so it's
        # covered by converting unicode strings.

        # A lot of the build backend code is currently expecting byte strings
        # and breaks in subtle ways with unicode strings.
        return config_status(args=[], **encode(sanitized_config, encoding))
    return 0

if __name__ == '__main__':