def test_traversal_all_vars(self):
        reader = self.reader('traversal-all-vars')
        emitter = TreeMetadataEmitter(reader.config)

        objs = list(emitter.emit(reader.read_topsrcdir()))
        self.assertEqual(len(objs), 6)

        for o in objs:
            self.assertIsInstance(o, DirectoryTraversal)

        reldirs = set([o.relativedir for o in objs])
        self.assertEqual(reldirs, set(['', 'parallel', 'regular', 'test',
            'test_tool', 'tool']))

        for o in objs:
            reldir = o.relativedir

            if reldir == '':
                self.assertEqual(o.dirs, ['regular'])
                self.assertEqual(o.parallel_dirs, ['parallel'])
                self.assertEqual(o.test_dirs, ['test'])
                self.assertEqual(o.test_tool_dirs, ['test_tool'])
                self.assertEqual(o.tool_dirs, ['tool'])
                self.assertEqual(o.external_make_dirs, ['external_make'])
                self.assertEqual(o.parallel_external_make_dirs,
                    ['parallel_external_make'])

    def _emit(self, name, env=None):
        if not env:
            env = self._get_environment(name)

        reader = BuildReader(env)
        emitter = TreeMetadataEmitter(env)

        return env, emitter.emit(reader.read_topsrcdir())

    def test_tier_simple(self):
        reader = self.reader('traversal-tier-simple')
        emitter = TreeMetadataEmitter(reader.config)

        objs = list(emitter.emit(reader.read_topsrcdir()))
        self.assertEqual(len(objs), 4)

        reldirs = [o.relativedir for o in objs]
        self.assertEqual(reldirs, ['', 'foo', 'foo/biz', 'bar'])

    def read_topsrcdir(self, reader, filter_common=True):
        emitter = TreeMetadataEmitter(reader.config)
        objs = list(emitter.emit(reader.read_topsrcdir()))
        self.assertGreater(len(objs), 0)

        filtered = []
        for obj in objs:
            if filter_common and isinstance(obj, DirectoryTraversal):
                continue

            filtered.append(obj)

        return filtered

    def test_config_file_substitution(self):
        reader = self.reader('config-file-substitution')
        emitter = TreeMetadataEmitter(reader.config)

        objs = list(emitter.emit(reader.read_topsrcdir()))
        self.assertEqual(len(objs), 3)

        self.assertIsInstance(objs[0], DirectoryTraversal)
        self.assertIsInstance(objs[1], ConfigFileSubstitution)
        self.assertIsInstance(objs[2], ConfigFileSubstitution)

        topobjdir = os.path.abspath(reader.config.topobjdir)
        self.assertEqual(os.path.normpath(objs[1].output_path),
            os.path.normpath(os.path.join(topobjdir, 'foo')))
        self.assertEqual(os.path.normpath(objs[2].output_path),
            os.path.normpath(os.path.join(topobjdir, 'bar')))

def gen_test_backend():
    build_obj = MozbuildObject.from_environment()
    try:
        config = build_obj.config_environment
    except BuildEnvironmentNotFoundException:
        print("No build detected, test metadata may be incomplete.")
        config = EmptyConfig(build_obj.topsrcdir)
        config.topobjdir = build_obj.topobjdir

    reader = BuildReader(config)
    emitter = TreeMetadataEmitter(config)
    backend = TestManifestBackend(config)

    context = reader.read_topsrcdir()
    data = emitter.emit(context, emitfn=emitter._process_test_manifests)
    backend.consume(data)

    def test_mtime_no_change(self):
        """Ensure mtime is not updated if file content does not change."""

        env = self._consume('stub0', RecursiveMakeBackend)

        makefile_path = mozpath.join(env.topobjdir, 'Makefile')
        backend_path = mozpath.join(env.topobjdir, 'backend.mk')
        makefile_mtime = os.path.getmtime(makefile_path)
        backend_mtime = os.path.getmtime(backend_path)

        reader = BuildReader(env)
        emitter = TreeMetadataEmitter(env)
        backend = RecursiveMakeBackend(env)
        backend.consume(emitter.emit(reader.read_topsrcdir()))

        self.assertEqual(os.path.getmtime(makefile_path), makefile_mtime)
        self.assertEqual(os.path.getmtime(backend_path), backend_mtime)

    def do_test_backend(self, *backends, **kwargs):
        topobjdir = mkdtemp()
        try:
            config = ConfigEnvironment(buildconfig.topsrcdir, topobjdir,
                                       **kwargs)
            reader = BuildReader(config)
            emitter = TreeMetadataEmitter(config)
            moz_build = mozpath.join(config.topsrcdir, 'test.mozbuild')
            definitions = list(emitter.emit(
                reader.read_mozbuild(moz_build, config)))
            for backend in backends:
                backend(config).consume(definitions)

            yield config
        except:
            raise
        finally:
            if not os.environ.get('MOZ_NO_CLEANUP'):
                shutil.rmtree(topobjdir)

    def read_topsrcdir(self, reader, filter_common=True):
        emitter = TreeMetadataEmitter(reader.config)
        def ack(obj):
            obj.ack()
            return obj

        objs = list(ack(o) for o in emitter.emit(reader.read_topsrcdir()))
        self.assertGreater(len(objs), 0)
        self.assertIsInstance(objs[-1], ReaderSummary)

        filtered = []
        for obj in objs:
            if filter_common and isinstance(obj, DirectoryTraversal):
                continue

            # Always filter ReaderSummary because it's asserted above.
            if isinstance(obj, ReaderSummary):
                continue

            filtered.append(obj)

        return filtered

def gen_test_backend():
    build_obj = MozbuildObject.from_environment()
    try:
        config = build_obj.config_environment
    except BuildEnvironmentNotFoundException:
        print("No build detected, test metadata may be incomplete.")

        # If 'JS_STANDALONE' is set, tests that don't require an objdir won't
        # be picked up due to bug 1345209.
        substs = EmptyConfig.default_substs
        if 'JS_STANDALONE' in substs:
            del substs['JS_STANDALONE']

        config = EmptyConfig(build_obj.topsrcdir, substs)
        config.topobjdir = build_obj.topobjdir

    reader = BuildReader(config)
    emitter = TreeMetadataEmitter(config)
    backend = TestManifestBackend(config)

    context = reader.read_topsrcdir()
    data = emitter.emit(context, emitfn=emitter._process_test_manifests)
    backend.consume(data)

def config_status(topobjdir='.', topsrcdir='.', defines=None,
                  non_global_defines=None, substs=None, source=None,
                  mozconfig=None):
    '''Main function, providing config.status functionality.

    Contrary to config.status, it doesn't use CONFIG_FILES or CONFIG_HEADERS
    variables.

    Without the -n option, this program acts as config.status and considers
    the current directory as the top object directory, even when config.status
    is in a different directory. It will, however, treat the directory
    containing config.status as the top object directory with the -n option.

    The options to this function are passed when creating the
    ConfigEnvironment. These lists, as well as the actual wrapper script
    around this function, are meant to be generated by configure.
    See build/autoconf/config.status.m4.
    '''

    if 'CONFIG_FILES' in os.environ:
        raise Exception('Using the CONFIG_FILES environment variable is not '
            'supported.')
    if 'CONFIG_HEADERS' in os.environ:
        raise Exception('Using the CONFIG_HEADERS environment variable is not '
            'supported.')

    if not os.path.isabs(topsrcdir):
        raise Exception('topsrcdir must be defined as an absolute directory: '
            '%s' % topsrcdir)

    default_backends = ['RecursiveMake']
    default_backends = (substs or {}).get('BUILD_BACKENDS', ['RecursiveMake'])

    parser = ArgumentParser()
    parser.add_argument('-v', '--verbose', dest='verbose', action='store_true',
                        help='display verbose output')
    parser.add_argument('-n', dest='not_topobjdir', action='store_true',
                        help='do not consider current directory as top object directory')
    parser.add_argument('-d', '--diff', action='store_true',
                        help='print diffs of changed files.')
    parser.add_argument('-b', '--backend', nargs='+', choices=sorted(backends),
                        default=default_backends,
                        help='what backend to build (default: %s).' %
                        ' '.join(default_backends))
    parser.add_argument('--dry-run', action='store_true',
                        help='do everything except writing files out.')
    options = parser.parse_args()

    # Without -n, the current directory is meant to be the top object directory
    if not options.not_topobjdir:
        topobjdir = os.path.abspath('.')

    env = ConfigEnvironment(topsrcdir, topobjdir, defines=defines,
            non_global_defines=non_global_defines, substs=substs,
            source=source, mozconfig=mozconfig)

    # mozinfo.json only needs written if configure changes and configure always
    # passes this environment variable.
    if 'WRITE_MOZINFO' in os.environ:
        write_mozinfo(os.path.join(topobjdir, 'mozinfo.json'), env, os.environ)

    cpu_start = time.clock()
    time_start = time.time()

    # Make appropriate backend instances, defaulting to RecursiveMakeBackend,
    # or what is in BUILD_BACKENDS.
    selected_backends = [get_backend_class(b)(env) for b in options.backend]

    if options.dry_run:
        for b in selected_backends:
            b.dry_run = True

    reader = BuildReader(env)
    emitter = TreeMetadataEmitter(env)
    # This won't actually do anything because of the magic of generators.
    definitions = emitter.emit(reader.read_topsrcdir())

    log_level = logging.DEBUG if options.verbose else logging.INFO
    log_manager.add_terminal_logging(level=log_level)
    log_manager.enable_unstructured()

    print('Reticulating splines...', file=sys.stderr)
    if len(selected_backends) > 1:
        definitions = list(definitions)

    for the_backend in selected_backends:
        the_backend.consume(definitions)

    execution_time = 0.0
    for obj in chain((reader, emitter), selected_backends):
        summary = obj.summary()
        print(summary, file=sys.stderr)
        execution_time += summary.execution_time

    cpu_time = time.clock() - cpu_start
    wall_time = time.time() - time_start
    efficiency = cpu_time / wall_time if wall_time else 100
    untracked = wall_time - execution_time

    print(
#.........这里部分代码省略.........

#.........这里部分代码省略.........

    # Without -n, the current directory is meant to be the top object directory
    if not options.not_topobjdir:
        topobjdir = os.path.abspath('.')

    env = ConfigEnvironment(topsrcdir, topobjdir, defines=defines,
            non_global_defines=non_global_defines, substs=substs, source=source)

    # mozinfo.json only needs written if configure changes and configure always
    # passes this environment variable.
    if 'WRITE_MOZINFO' in os.environ:
        write_mozinfo(os.path.join(topobjdir, 'mozinfo.json'), env, os.environ)

    # Make an appropriate backend instance, defaulting to RecursiveMakeBackend.
    backends_cls = []
    for backend in options.backend:
        if backend == 'AndroidEclipse':
            from mozbuild.backend.android_eclipse import AndroidEclipseBackend
            if not MachCommandConditions.is_android(env):
                raise Exception('The Android Eclipse backend is not available with this configuration.')
            backends_cls.append(AndroidEclipseBackend)
        elif backend == 'CppEclipse':
            from mozbuild.backend.cpp_eclipse import CppEclipseBackend
            backends_cls.append(CppEclipseBackend)
            if os.name == 'nt':
              raise Exception('Eclipse is not supported on Windows. Consider using Visual Studio instead.')
        elif backend == 'VisualStudio':
            from mozbuild.backend.visualstudio import VisualStudioBackend
            backends_cls.append(VisualStudioBackend)
        elif backend == 'FasterMake':
            from mozbuild.backend.fastermake import FasterMakeBackend
            backends_cls.append(FasterMakeBackend)
        elif backend == 'CompileDB':
            from mozbuild.compilation.database import CompileDBBackend
            backends_cls.append(CompileDBBackend)
        else:
            backends_cls.append(RecursiveMakeBackend)

    cpu_start = time.clock()
    time_start = time.time()

    backends = [cls(env) for cls in backends_cls]

    reader = BuildReader(env)
    emitter = TreeMetadataEmitter(env)
    # This won't actually do anything because of the magic of generators.
    definitions = emitter.emit(reader.read_topsrcdir())

    if options.recheck:
        # Execute configure from the top object directory
        os.chdir(topobjdir)
        os.execlp('sh', 'sh', '-c', ' '.join([os.path.join(topsrcdir, 'configure'), env.substs['ac_configure_args'], '--no-create', '--no-recursion']))

    log_level = logging.DEBUG if options.verbose else logging.INFO
    log_manager.add_terminal_logging(level=log_level)
    log_manager.enable_unstructured()

    print('Reticulating splines...', file=sys.stderr)
    if len(backends) > 1:
        definitions = list(definitions)

    for the_backend in backends:
        the_backend.consume(definitions)

    execution_time = 0.0
    for obj in chain((reader, emitter), backends):
        summary = obj.summary()
        print(summary, file=sys.stderr)
        execution_time += summary.execution_time

    cpu_time = time.clock() - cpu_start
    wall_time = time.time() - time_start
    efficiency = cpu_time / wall_time if wall_time else 100
    untracked = wall_time - execution_time

    print(
        'Total wall time: {:.2f}s; CPU time: {:.2f}s; Efficiency: '
        '{:.0%}; Untracked: {:.2f}s'.format(
            wall_time, cpu_time, efficiency, untracked),
        file=sys.stderr
    )

    if options.diff:
        for the_backend in backends:
            for path, diff in sorted(the_backend.file_diffs.items()):
                print('\n'.join(diff))

    # Advertise Visual Studio if appropriate.
    if os.name == 'nt' and 'VisualStudio' not in options.backend:
        print(VISUAL_STUDIO_ADVERTISEMENT)

    # Advertise Eclipse if it is appropriate.
    if MachCommandConditions.is_android(env):
        if 'AndroidEclipse' not in options.backend:
            print(ANDROID_IDE_ADVERTISEMENT)

    if env.substs.get('MOZ_ARTIFACT_BUILDS', False):
        # Execute |mach artifact install| from the top source directory.
        os.chdir(topsrcdir)
        return subprocess.check_call([sys.executable, os.path.join(topsrcdir, 'mach'), 'artifact', 'install'])

def config_status(topobjdir = '.', topsrcdir = '.',
                  defines = [], non_global_defines = [], substs = [],
                  files = [], headers = []):
    '''Main function, providing config.status functionality.

    Contrary to config.status, it doesn't use CONFIG_FILES or CONFIG_HEADERS
    variables, but like config.status from autoconf 2.6, single files may be
    generated with the --file and --header options. Several such options can
    be given to generate several files at the same time.

    Without the -n option, this program acts as config.status and considers
    the current directory as the top object directory, even when config.status
    is in a different directory. It will, however, treat the directory
    containing config.status as the top object directory with the -n option,
    while files given to the --file and --header arguments are considered
    relative to the current directory.

    The --recheck option, like with the original config.status, runs configure
    again, with the options given in the "ac_configure_args" subst.

    The options to this function are passed when creating the
    ConfigEnvironment, except for files and headers, which contain the list
    of files and headers to be generated by default. These lists, as well as
    the actual wrapper script around this function, are meant to be generated
    by configure. See build/autoconf/config.status.m4.

    Unlike config.status behaviour with CONFIG_FILES and CONFIG_HEADERS,
    but like config.status behaviour with --file and --header, providing
    files or headers on the command line inhibits the default generation of
    files when given headers and headers when given files.

    Unlike config.status, the FILE:TEMPLATE syntax is not supported for
    files and headers. The template is always the filename suffixed with
    '.in', in the corresponding directory under the top source directory.
    '''

    if 'CONFIG_FILES' in os.environ:
        raise Exception, 'Using the CONFIG_FILES environment variable is not supported. Use --file instead.'
    if 'CONFIG_HEADERS' in os.environ:
        raise Exception, 'Using the CONFIG_HEADERS environment variable is not supported. Use --header instead.'

    parser = OptionParser()
    parser.add_option('--recheck', dest='recheck', action='store_true',
                      help='update config.status by reconfiguring in the same conditions')
    parser.add_option('--file', dest='files', metavar='FILE', action='append',
                      help='instantiate the configuration file FILE')
    parser.add_option('--header', dest='headers', metavar='FILE', action='append',
                      help='instantiate the configuration header FILE')
    parser.add_option('-v', '--verbose', dest='verbose', action='store_true',
                      help='display verbose output')
    parser.add_option('-n', dest='not_topobjdir', action='store_true',
                      help='do not consider current directory as top object directory')
    (options, args) = parser.parse_args()

    # Without -n, the current directory is meant to be the top object directory
    if not options.not_topobjdir:
        topobjdir = '.'

    env = ConfigEnvironment(topsrcdir, topobjdir, defines=defines,
            non_global_defines=non_global_defines, substs=substs)

    reader = BuildReader(env)
    emitter = TreeMetadataEmitter(env)
    backend = RecursiveMakeBackend(env)
    # This won't actually do anything because of the magic of generators.
    definitions = emitter.emit(reader.read_topsrcdir())

    if options.recheck:
        # Execute configure from the top object directory
        if not os.path.isabs(topsrcdir):
            topsrcdir = relpath(topsrcdir, topobjdir)
        os.chdir(topobjdir)
        os.execlp('sh', 'sh', '-c', ' '.join([os.path.join(topsrcdir, 'configure'), env.substs['ac_configure_args'], '--no-create', '--no-recursion']))

    if options.files:
        files = options.files
        headers = []
    if options.headers:
        headers = options.headers
        if not options.files:
            files = []
    # Default to display messages when giving --file or --headers on the
    # command line.
    log_level = logging.INFO

    if options.files or options.headers or options.verbose:
        log_level = logging.DEBUG

    log_manager.add_terminal_logging(level=log_level)
    log_manager.enable_unstructured()

    if not options.files and not options.headers:
        print('Reticulating splines...', file=sys.stderr)
        summary = backend.consume(definitions)

        for line in summary.summaries():
            print(line, file=sys.stderr)

        files = [os.path.join(topobjdir, f) for f in files]
        headers = [os.path.join(topobjdir, f) for f in headers]
#.........这里部分代码省略.........

def config_status(topobjdir='.', topsrcdir='.',
        defines=[], non_global_defines=[], substs=[], source=None):
    '''Main function, providing config.status functionality.

    Contrary to config.status, it doesn't use CONFIG_FILES or CONFIG_HEADERS
    variables.

    Without the -n option, this program acts as config.status and considers
    the current directory as the top object directory, even when config.status
    is in a different directory. It will, however, treat the directory
    containing config.status as the top object directory with the -n option.

    The --recheck option, like with the original config.status, runs configure
    again, with the options given in the "ac_configure_args" subst.

    The options to this function are passed when creating the
    ConfigEnvironment. These lists, as well as the actual wrapper script
    around this function, are meant to be generated by configure.
    See build/autoconf/config.status.m4.
    '''

    if 'CONFIG_FILES' in os.environ:
        raise Exception('Using the CONFIG_FILES environment variable is not '
            'supported.')
    if 'CONFIG_HEADERS' in os.environ:
        raise Exception('Using the CONFIG_HEADERS environment variable is not '
            'supported.')

    if not os.path.isabs(topsrcdir):
        raise Exception('topsrcdir must be defined as an absolute directory: '
            '%s' % topsrcdir)

    parser = OptionParser()
    parser.add_option('--recheck', dest='recheck', action='store_true',
                      help='update config.status by reconfiguring in the same conditions')
    parser.add_option('-v', '--verbose', dest='verbose', action='store_true',
                      help='display verbose output')
    parser.add_option('-n', dest='not_topobjdir', action='store_true',
                      help='do not consider current directory as top object directory')
    parser.add_option('-d', '--diff', action='store_true',
                      help='print diffs of changed files.')
    options, args = parser.parse_args()

    # Without -n, the current directory is meant to be the top object directory
    if not options.not_topobjdir:
        topobjdir = os.path.abspath('.')

    env = ConfigEnvironment(topsrcdir, topobjdir, defines=defines,
            non_global_defines=non_global_defines, substs=substs, source=source)

    # mozinfo.json only needs written if configure changes and configure always
    # passes this environment variable.
    if 'WRITE_MOZINFO' in os.environ:
        write_mozinfo(os.path.join(topobjdir, 'mozinfo.json'), env, os.environ)

    reader = BuildReader(env)
    emitter = TreeMetadataEmitter(env)
    backend = RecursiveMakeBackend(env)
    # This won't actually do anything because of the magic of generators.
    definitions = emitter.emit(reader.read_topsrcdir())

    if options.recheck:
        # Execute configure from the top object directory
        os.chdir(topobjdir)
        os.execlp('sh', 'sh', '-c', ' '.join([os.path.join(topsrcdir, 'configure'), env.substs['ac_configure_args'], '--no-create', '--no-recursion']))

    log_level = logging.DEBUG if options.verbose else logging.INFO
    log_manager.add_terminal_logging(level=log_level)
    log_manager.enable_unstructured()

    print('Reticulating splines...', file=sys.stderr)
    summary = backend.consume(definitions)

    for line in summary.summaries():
        print(line, file=sys.stderr)

    if options.diff:
        for path, diff in sorted(summary.file_diffs.items()):
            print(diff)

#.........这里部分代码省略.........
        dest="not_topobjdir",
        action="store_true",
        help="do not consider current directory as top object directory",
    )
    parser.add_option("-d", "--diff", action="store_true", help="print diffs of changed files.")
    parser.add_option(
        "-b",
        "--backend",
        choices=["RecursiveMake", "AndroidEclipse", "CppEclipse", "VisualStudio", "Build", "ForceBuild"],
        default="Build",
        help="what backend to build (default: RecursiveMake).",
    )
    options, args = parser.parse_args()

    # Without -n, the current directory is meant to be the top object directory
    if not options.not_topobjdir:
        topobjdir = os.path.abspath(".")

    env = ConfigEnvironment(
        topsrcdir, topobjdir, defines=defines, non_global_defines=non_global_defines, substs=substs, source=source
    )

    # mozinfo.json only needs written if configure changes and configure always
    # passes this environment variable.
    if "WRITE_MOZINFO" in os.environ:
        write_mozinfo(os.path.join(topobjdir, "mozinfo.json"), env, os.environ)

    # Make an appropriate backend instance, defaulting to RecursiveMakeBackend.
    backend_cls = RecursiveMakeBackend
    if options.backend == "AndroidEclipse":
        from mozbuild.backend.android_eclipse import AndroidEclipseBackend

        if not MachCommandConditions.is_android(env):
            raise Exception("The Android Eclipse backend is not available with this configuration.")
        backend_cls = AndroidEclipseBackend
    elif options.backend == "CppEclipse":
        from mozbuild.backend.cpp_eclipse import CppEclipseBackend

        backend_cls = CppEclipseBackend
        if os.name == "nt":
            raise Exception("Eclipse is not supported on Windows. Consider using Visual Studio instead.")
    elif options.backend == "VisualStudio":
        from mozbuild.backend.visualstudio import VisualStudioBackend

        backend_cls = VisualStudioBackend
    elif options.backend == "Build":
        from mozbuild.backend.visualstudio import VisualStudioBackend

        backend_cls = VisualStudioBackend
    elif options.backend == "ForceBuild":
        from mozbuild.backend.visualstudio import VisualStudioBackend

        backend_cls = VisualStudioBackend

    the_backend = backend_cls(env)
    if options.backend == "Build":
        if the_backend.try_build():
            return
    elif options.backend == "ForceBuild":
        the_backend.full_build()

    reader = BuildReader(env)
    emitter = TreeMetadataEmitter(env)
    # This won't actually do anything because of the magic of generators.
    definitions = emitter.emit(reader.read_topsrcdir())

    if options.recheck:
        # Execute configure from the top object directory
        os.chdir(topobjdir)
        os.execlp(
            "sh",
            "sh",
            "-c",
            " ".join(
                [os.path.join(topsrcdir, "configure"), env.substs["ac_configure_args"], "--no-create", "--no-recursion"]
            ),
        )

    log_level = logging.DEBUG if options.verbose else logging.INFO
    log_manager.add_terminal_logging(level=log_level)
    log_manager.enable_unstructured()

    print("Reticulating splines...", file=sys.stderr)
    summary = the_backend.consume(definitions)

    for line in summary.summaries():
        print(line, file=sys.stderr)

    if options.diff:
        for path, diff in sorted(summary.file_diffs.items()):
            print("\n".join(diff))

    # Advertise Visual Studio if appropriate.
    if os.name == "nt" and options.backend == "RecursiveMake":
        print(VISUAL_STUDIO_ADVERTISEMENT)

    # Advertise Eclipse if it is appropriate.
    if MachCommandConditions.is_android(env):
        if options.backend == "RecursiveMake":
            print(ANDROID_IDE_ADVERTISEMENT)

def config_status(topobjdir='.', topsrcdir='.',
        defines=[], non_global_defines=[], substs=[], source=None):
    '''Main function, providing config.status functionality.

    Contrary to config.status, it doesn't use CONFIG_FILES or CONFIG_HEADERS
    variables.

    Without the -n option, this program acts as config.status and considers
    the current directory as the top object directory, even when config.status
    is in a different directory. It will, however, treat the directory
    containing config.status as the top object directory with the -n option.

    The --recheck option, like with the original config.status, runs configure
    again, with the options given in the "ac_configure_args" subst.

    The options to this function are passed when creating the
    ConfigEnvironment. These lists, as well as the actual wrapper script
    around this function, are meant to be generated by configure.
    See build/autoconf/config.status.m4.
    '''

    if 'CONFIG_FILES' in os.environ:
        raise Exception('Using the CONFIG_FILES environment variable is not '
            'supported.')
    if 'CONFIG_HEADERS' in os.environ:
        raise Exception('Using the CONFIG_HEADERS environment variable is not '
            'supported.')

    if not os.path.isabs(topsrcdir):
        raise Exception('topsrcdir must be defined as an absolute directory: '
            '%s' % topsrcdir)

    parser = OptionParser()
    parser.add_option('--recheck', dest='recheck', action='store_true',
                      help='update config.status by reconfiguring in the same conditions')
    parser.add_option('-v', '--verbose', dest='verbose', action='store_true',
                      help='display verbose output')
    parser.add_option('-n', dest='not_topobjdir', action='store_true',
                      help='do not consider current directory as top object directory')
    parser.add_option('-d', '--diff', action='store_true',
                      help='print diffs of changed files.')
    parser.add_option('-b', '--backend',
                      choices=['RecursiveMake', 'AndroidEclipse', 'CppEclipse', 'VisualStudio'],
                      default='RecursiveMake',
                      help='what backend to build (default: RecursiveMake).')
    options, args = parser.parse_args()

    # Without -n, the current directory is meant to be the top object directory
    if not options.not_topobjdir:
        topobjdir = os.path.abspath('.')

    env = ConfigEnvironment(topsrcdir, topobjdir, defines=defines,
            non_global_defines=non_global_defines, substs=substs, source=source)

    # mozinfo.json only needs written if configure changes and configure always
    # passes this environment variable.
    if 'WRITE_MOZINFO' in os.environ:
        write_mozinfo(os.path.join(topobjdir, 'mozinfo.json'), env, os.environ)

    # Make an appropriate backend instance, defaulting to RecursiveMakeBackend.
    backend_cls = RecursiveMakeBackend
    if options.backend == 'AndroidEclipse':
        from mozbuild.backend.android_eclipse import AndroidEclipseBackend
        if not MachCommandConditions.is_android(env):
            raise Exception('The Android Eclipse backend is not available with this configuration.')
        backend_cls = AndroidEclipseBackend
    elif options.backend == 'CppEclipse':
        from mozbuild.backend.cpp_eclipse import CppEclipseBackend
        backend_cls = CppEclipseBackend
        if os.name == 'nt':
          raise Exception('Eclipse is not supported on Windows. Consider using Visual Studio instead.')
    elif options.backend == 'VisualStudio':
        from mozbuild.backend.visualstudio import VisualStudioBackend
        backend_cls = VisualStudioBackend

    the_backend = backend_cls(env)

    reader = BuildReader(env)
    emitter = TreeMetadataEmitter(env)
    # This won't actually do anything because of the magic of generators.
    definitions = emitter.emit(reader.read_topsrcdir())

    if options.recheck:
        # Execute configure from the top object directory
        os.chdir(topobjdir)
        os.execlp('sh', 'sh', '-c', ' '.join([os.path.join(topsrcdir, 'configure'), env.substs['ac_configure_args'], '--no-create', '--no-recursion']))

    log_level = logging.DEBUG if options.verbose else logging.INFO
    log_manager.add_terminal_logging(level=log_level)
    log_manager.enable_unstructured()

    print('Reticulating splines...', file=sys.stderr)
    summary = the_backend.consume(definitions)

    for line in summary.summaries():
        print(line, file=sys.stderr)

    if options.diff:
        for path, diff in sorted(summary.file_diffs.items()):
            print('\n'.join(diff))
#.........这里部分代码省略.........