8 files changed, 966 insertions, 0 deletions
diff --git a/src/flake8/main/__init__.py b/src/flake8/main/__init__.py
new file mode 100644
index 0000000..d3aa1de
--- /dev/null
+++ b/src/flake8/main/__init__.py
@@ -0,0 +1 @@
+"""Module containing the logic for the Flake8 entry-points."""
diff --git a/src/flake8/main/application.py b/src/flake8/main/application.py
new file mode 100644
index 0000000..225c701
--- /dev/null
+++ b/src/flake8/main/application.py
@@ -0,0 +1,296 @@
+"""Module containing the application logic for Flake8."""
+from __future__ import print_function
+
+import logging
+import sys
+import time
+
+import flake8
+from flake8 import checker
+from flake8 import defaults
+from flake8 import style_guide
+from flake8 import utils
+from flake8.main import options
+from flake8.options import aggregator
+from flake8.options import manager
+from flake8.plugins import manager as plugin_manager
+
+LOG = logging.getLogger(__name__)
+
+
+class Application(object):
+    """Abstract our application into a class."""
+
+    def __init__(self, program='flake8', version=flake8.__version__):
+        # type: (str, str) -> NoneType
+        """Initialize our application.
+
+        :param str program:
+            The name of the program/application that we're executing.
+        :param str version:
+            The version of the program/application we're executing.
+        """
+        #: The timestamp when the Application instance was instantiated.
+        self.start_time = time.time()
+        #: The timestamp when the Application finished reported errors.
+        self.end_time = None
+        #: The name of the program being run
+        self.program = program
+        #: The version of the program being run
+        self.version = version
+        #: The instance of :class:`flake8.options.manager.OptionManager` used
+        #: to parse and handle the options and arguments passed by the user
+        self.option_manager = manager.OptionManager(
+            prog='flake8', version=flake8.__version__
+        )
+        options.register_default_options(self.option_manager)
+
+        # We haven't found or registered our plugins yet, so let's defer
+        # printing the version until we aggregate options from config files
+        # and the command-line. First, let's clone our arguments on the CLI,
+        # then we'll attempt to remove ``--version`` so that we can avoid
+        # triggering the "version" action in optparse. If it's not there, we
+        # do not need to worry and we can continue. If it is, we successfully
+        # defer printing the version until just a little bit later.
+        # Similarly we have to defer printing the help text until later.
+        args = sys.argv[:]
+        try:
+            args.remove('--version')
+        except ValueError:
+            pass
+        try:
+            args.remove('--help')
+        except ValueError:
+            pass
+        try:
+            args.remove('-h')
+        except ValueError:
+            pass
+
+        preliminary_opts, _ = self.option_manager.parse_args(args)
+        # Set the verbosity of the program
+        flake8.configure_logging(preliminary_opts.verbose,
+                                 preliminary_opts.output_file)
+
+        #: The instance of :class:`flake8.plugins.manager.Checkers`
+        self.check_plugins = None
+        #: The instance of :class:`flake8.plugins.manager.Listeners`
+        self.listening_plugins = None
+        #: The instance of :class:`flake8.plugins.manager.ReportFormatters`
+        self.formatting_plugins = None
+        #: The user-selected formatter from :attr:`formatting_plugins`
+        self.formatter = None
+        #: The :class:`flake8.plugins.notifier.Notifier` for listening plugins
+        self.listener_trie = None
+        #: The :class:`flake8.style_guide.StyleGuide` built from the user's
+        #: options
+        self.guide = None
+        #: The :class:`flake8.checker.Manager` that will handle running all of
+        #: the checks selected by the user.
+        self.file_checker_manager = None
+
+        #: The user-supplied options parsed into an instance of
+        #: :class:`optparse.Values`
+        self.options = None
+        #: The left over arguments that were not parsed by
+        #: :attr:`option_manager`
+        self.args = None
+        #: The number of errors, warnings, and other messages after running
+        #: flake8 and taking into account ignored errors and lines.
+        self.result_count = 0
+        #: The total number of errors before accounting for ignored errors and
+        #: lines.
+        self.total_result_count = 0
+
+        #: Whether the program is processing a diff or not
+        self.running_against_diff = False
+        #: The parsed diff information
+        self.parsed_diff = {}
+
+    def exit(self):
+        # type: () -> NoneType
+        """Handle finalization and exiting the program.
+
+        This should be the last thing called on the application instance. It
+        will check certain options and exit appropriately.
+        """
+        if self.options.count:
+            print(self.result_count)
+
+        if not self.options.exit_zero:
+            raise SystemExit(self.result_count > 0)
+
+    def find_plugins(self):
+        # type: () -> NoneType
+        """Find and load the plugins for this application.
+
+        If :attr:`check_plugins`, :attr:`listening_plugins`, or
+        :attr:`formatting_plugins` are ``None`` then this method will update
+        them with the appropriate plugin manager instance. Given the expense
+        of finding plugins (via :mod:`pkg_resources`) we want this to be
+        idempotent and so only update those attributes if they are ``None``.
+        """
+        if self.check_plugins is None:
+            self.check_plugins = plugin_manager.Checkers()
+
+        if self.listening_plugins is None:
+            self.listening_plugins = plugin_manager.Listeners()
+
+        if self.formatting_plugins is None:
+            self.formatting_plugins = plugin_manager.ReportFormatters()
+
+        self.check_plugins.load_plugins()
+        self.listening_plugins.load_plugins()
+        self.formatting_plugins.load_plugins()
+
+    def register_plugin_options(self):
+        # type: () -> NoneType
+        """Register options provided by plugins to our option manager."""
+        self.check_plugins.register_options(self.option_manager)
+        self.check_plugins.register_plugin_versions(self.option_manager)
+        self.listening_plugins.register_options(self.option_manager)
+        self.formatting_plugins.register_options(self.option_manager)
+
+    def parse_configuration_and_cli(self, argv=None):
+        # type: (Union[NoneType, List[str]]) -> NoneType
+        """Parse configuration files and the CLI options.
+
+        :param list argv:
+            Command-line arguments passed in directly.
+        """
+        if self.options is None and self.args is None:
+            self.options, self.args = aggregator.aggregate_options(
+                self.option_manager, argv
+            )
+
+        self.running_against_diff = self.options.diff
+        if self.running_against_diff:
+            self.parsed_diff = utils.parse_unified_diff()
+
+        self.check_plugins.provide_options(self.option_manager, self.options,
+                                           self.args)
+        self.listening_plugins.provide_options(self.option_manager,
+                                               self.options,
+                                               self.args)
+        self.formatting_plugins.provide_options(self.option_manager,
+                                                self.options,
+                                                self.args)
+
+    def make_formatter(self):
+        # type: () -> NoneType
+        """Initialize a formatter based on the parsed options."""
+        if self.formatter is None:
+            self.formatter = self.formatting_plugins.get(
+                self.options.format, self.formatting_plugins['default']
+            ).execute(self.options)
+
+    def make_notifier(self):
+        # type: () -> NoneType
+        """Initialize our listener Notifier."""
+        if self.listener_trie is None:
+            self.listener_trie = self.listening_plugins.build_notifier()
+
+    def make_guide(self):
+        # type: () -> NoneType
+        """Initialize our StyleGuide."""
+        if self.guide is None:
+            self.guide = style_guide.StyleGuide(
+                self.options, self.listener_trie, self.formatter
+            )
+
+        if self.running_against_diff:
+            self.guide.add_diff_ranges(self.parsed_diff)
+
+    def make_file_checker_manager(self):
+        # type: () -> NoneType
+        """Initialize our FileChecker Manager."""
+        if self.file_checker_manager is None:
+            self.file_checker_manager = checker.Manager(
+                style_guide=self.guide,
+                arguments=self.args,
+                checker_plugins=self.check_plugins,
+            )
+
+    def run_checks(self):
+        # type: () -> NoneType
+        """Run the actual checks with the FileChecker Manager.
+
+        This method encapsulates the logic to make a
+        :class:`~flake8.checker.Manger` instance run the checks it is
+        managing.
+        """
+        files = None
+        if self.running_against_diff:
+            files = list(sorted(self.parsed_diff.keys()))
+        self.file_checker_manager.start(files)
+        self.file_checker_manager.run()
+        LOG.info('Finished running')
+        self.file_checker_manager.stop()
+        self.end_time = time.time()
+
+    def report_benchmarks(self):
+        """Aggregate, calculate, and report benchmarks for this run."""
+        if not self.options.benchmark:
+            return
+
+        time_elapsed = self.end_time - self.start_time
+        statistics = [('seconds elapsed', time_elapsed)]
+        add_statistic = statistics.append
+        for statistic in (defaults.STATISTIC_NAMES + ('files',)):
+            value = self.file_checker_manager.statistics[statistic]
+            total_description = 'total ' + statistic + ' processed'
+            add_statistic((total_description, value))
+            per_second_description = statistic + ' processed per second'
+            add_statistic((per_second_description, int(value / time_elapsed)))
+
+        self.formatter.show_benchmarks(statistics)
+
+    def report_errors(self):
+        # type: () -> NoneType
+        """Report all the errors found by flake8 3.0.
+
+        This also updates the :attr:`result_count` attribute with the total
+        number of errors, warnings, and other messages found.
+        """
+        LOG.info('Reporting errors')
+        results = self.file_checker_manager.report()
+        self.total_result_count, self.result_count = results
+        LOG.info('Found a total of %d results and reported %d',
+                 self.total_result_count, self.result_count)
+
+    def initialize(self, argv):
+        # type: () -> NoneType
+        """Initialize the application to be run.
+
+        This finds the plugins, registers their options, and parses the
+        command-line arguments.
+        """
+        self.find_plugins()
+        self.register_plugin_options()
+        self.parse_configuration_and_cli(argv)
+        self.make_formatter()
+        self.make_notifier()
+        self.make_guide()
+        self.make_file_checker_manager()
+
+    def _run(self, argv):
+        # type: (Union[NoneType, List[str]]) -> NoneType
+        self.initialize(argv)
+        self.run_checks()
+        self.report_errors()
+        self.report_benchmarks()
+
+    def run(self, argv=None):
+        # type: (Union[NoneType, List[str]]) -> NoneType
+        """Run our application.
+
+        This method will also handle KeyboardInterrupt exceptions for the
+        entirety of the flake8 application. If it sees a KeyboardInterrupt it
+        will forcibly clean up the :class:`~flake8.checker.Manager`.
+        """
+        try:
+            self._run(argv)
+        except KeyboardInterrupt as exc:
+            LOG.critical('Caught keyboard interrupt from user')
+            LOG.exception(exc)
+            self.file_checker_manager._force_cleanup()
diff --git a/src/flake8/main/cli.py b/src/flake8/main/cli.py
new file mode 100644
index 0000000..29bd159
--- /dev/null
+++ b/src/flake8/main/cli.py
@@ -0,0 +1,17 @@
+"""Command-line implementation of flake8."""
+from flake8.main import application
+
+
+def main(argv=None):
+    # type: (Union[NoneType, List[str]]) -> NoneType
+    """Main entry-point for the flake8 command-line tool.
+
+    This handles the creation of an instance of :class:`Application`, runs it,
+    and then exits the application.
+
+    :param list argv:
+        The arguments to be passed to the application for parsing.
+    """
+    app = application.Application()
+    app.run(argv)
+    app.exit()
diff --git a/src/flake8/main/git.py b/src/flake8/main/git.py
new file mode 100644
index 0000000..bae0233
--- /dev/null
+++ b/src/flake8/main/git.py
@@ -0,0 +1,207 @@
+"""Module containing the main git hook interface and helpers.
+
+.. autofunction:: hook
+.. autofunction:: install
+
+"""
+import contextlib
+import os
+import shutil
+import stat
+import subprocess
+import sys
+import tempfile
+
+from flake8 import defaults
+from flake8 import exceptions
+
+__all__ = ('hook', 'install')
+
+
+def hook(lazy=False, strict=False):
+    """Execute Flake8 on the files in git's index.
+
+    Determine which files are about to be committed and run Flake8 over them
+    to check for violations.
+
+    :param bool lazy:
+        Find files not added to the index prior to committing. This is useful
+        if you frequently use ``git commit -a`` for example. This defaults to
+        False since it will otherwise include files not in the index.
+    :param bool strict:
+        If True, return the total number of errors/violations found by Flake8.
+        This will cause the hook to fail.
+    :returns:
+        Total number of errors found during the run.
+    :rtype:
+        int
+    """
+    # NOTE(sigmavirus24): Delay import of application until we need it.
+    from flake8.main import application
+    app = application.Application()
+    with make_temporary_directory() as tempdir:
+        filepaths = list(copy_indexed_files_to(tempdir, lazy))
+        app.initialize(filepaths)
+        app.run_checks()
+
+    app.report_errors()
+    if strict:
+        return app.result_count
+    return 0
+
+
+def install():
+    """Install the git hook script.
+
+    This searches for the ``.git`` directory and will install an executable
+    pre-commit python script in the hooks sub-directory if one does not
+    already exist.
+
+    :returns:
+        True if successful, False if the git directory doesn't exist.
+    :rtype:
+        bool
+    :raises:
+        flake8.exceptions.GitHookAlreadyExists
+    """
+    git_directory = find_git_directory()
+    if git_directory is None or not os.path.exists(git_directory):
+        return False
+
+    hooks_directory = os.path.join(git_directory, 'hooks')
+    if not os.path.exists(hooks_directory):
+        os.mkdir(hooks_directory)
+
+    pre_commit_file = os.path.abspath(
+        os.path.join(hooks_directory, 'pre-commit')
+    )
+    if os.path.exists(pre_commit_file):
+        raise exceptions.GitHookAlreadyExists(
+            'File already exists',
+            path=pre_commit_file,
+        )
+
+    executable = get_executable()
+
+    with open(pre_commit_file, 'w') as fd:
+        fd.write(_HOOK_TEMPLATE.format(executable=executable))
+
+    # NOTE(sigmavirus24): The following sets:
+    # - read, write, and execute permissions for the owner
+    # - read permissions for people in the group
+    # - read permissions for other people
+    # The owner needs the file to be readable, writable, and executable
+    # so that git can actually execute it as a hook.
+    pre_commit_permissions = stat.S_IRWXU | stat.S_IRGRP | stat.S_IROTH
+    os.chmod(pre_commit_file, pre_commit_permissions)
+    return True
+
+
+def get_executable():
+    if sys.executable is not None:
+        return sys.executable
+    return '/usr/bin/env python'
+
+
+def find_git_directory():
+    rev_parse = piped_process(['git', 'rev-parse', '--git-dir'])
+
+    (stdout, _) = rev_parse.communicate()
+    stdout = to_text(stdout)
+
+    if rev_parse.returncode == 0:
+        return stdout.strip()
+    return None
+
+
+def copy_indexed_files_to(temporary_directory, lazy):
+    modified_files = find_modified_files(lazy)
+    for filename in modified_files:
+        contents = get_staged_contents_from(filename)
+        yield copy_file_to(temporary_directory, filename, contents)
+
+
+def copy_file_to(destination_directory, filepath, contents):
+    directory, filename = os.path.split(os.path.abspath(filepath))
+    temporary_directory = make_temporary_directory_from(destination_directory,
+                                                        directory)
+    if not os.path.exists(temporary_directory):
+        os.makedirs(temporary_directory)
+    temporary_filepath = os.path.join(temporary_directory, filename)
+    with open(temporary_filepath, 'wb') as fd:
+        fd.write(contents)
+    return temporary_filepath
+
+
+def make_temporary_directory_from(destination, directory):
+    prefix = os.path.commonprefix([directory, destination])
+    common_directory_path = os.path.relpath(directory, start=prefix)
+    return os.path.join(destination, common_directory_path)
+
+
+def find_modified_files(lazy):
+    diff_index = piped_process(
+        ['git', 'diff-index', '--cached', '--name-only',
+         '--diff-filter=ACMRTUXB', 'HEAD'],
+    )
+
+    (stdout, _) = diff_index.communicate()
+    stdout = to_text(stdout)
+    return stdout.splitlines()
+
+
+def get_staged_contents_from(filename):
+    git_show = piped_process(['git', 'show', ':{0}'.format(filename)])
+    (stdout, _) = git_show.communicate()
+    return stdout
+
+
+@contextlib.contextmanager
+def make_temporary_directory():
+    temporary_directory = tempfile.mkdtemp()
+    yield temporary_directory
+    shutil.rmtree(temporary_directory, ignore_errors=True)
+
+
+def to_text(string):
+    """Ensure that the string is text."""
+    if callable(getattr(string, 'decode', None)):
+        return string.decode('utf-8')
+    return string
+
+
+def piped_process(command):
+    return subprocess.Popen(
+        command,
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+    )
+
+
+def git_config_for(parameter):
+    config = piped_process(['git', 'config', '--get', '--bool', parameter])
+    (stdout, _) = config.communicate()
+    return to_text(stdout)
+
+
+def config_for(parameter):
+    environment_variable = 'flake8_{0}'.format(parameter).upper()
+    git_variable = 'flake8.{0}'.format(parameter)
+    value = os.environ.get(environment_variable, git_config_for(git_variable))
+    return value.lower() in defaults.TRUTHY_VALUES
+
+
+_HOOK_TEMPLATE = """#!{executable}
+import os
+import sys
+
+from flake8.main import git
+
+if __name__ == '__main__':
+    sys.exit(
+        git.hook(
+            strict=git.config_for('strict'),
+            lazy=git.config_for('lazy'),
+        )
+    )
+"""
diff --git a/src/flake8/main/mercurial.py b/src/flake8/main/mercurial.py
new file mode 100644
index 0000000..d067612
--- /dev/null
+++ b/src/flake8/main/mercurial.py
@@ -0,0 +1,128 @@
+"""Module containing the main mecurial hook interface and helpers.
+
+.. autofunction:: hook
+.. autofunction:: install
+
+"""
+import configparser
+import os
+import subprocess
+
+from flake8 import exceptions as exc
+
+__all__ = ('hook', 'install')
+
+
+def hook(ui, repo, **kwargs):
+    """Execute Flake8 on the repository provided by Mercurial.
+
+    To understand the parameters read more of the Mercurial documentation
+    around Hooks: https://www.mercurial-scm.org/wiki/Hook.
+
+    We avoid using the ``ui`` attribute because it can cause issues with
+    the GPL license tha Mercurial is under. We don't import it, but we
+    avoid using it all the same.
+    """
+    from flake8.main import application
+    hgrc = find_hgrc(create_if_missing=False)
+    if hgrc is None:
+        print('Cannot locate your root mercurial repository.')
+        raise SystemExit(True)
+
+    hgconfig = configparser_for(hgrc)
+    strict = hgconfig.get('flake8', 'strict', fallback=True)
+
+    filenames = list(get_filenames_from(repo, kwargs))
+
+    app = application.Application()
+    app.run(filenames)
+
+    if strict:
+        return app.result_count
+    return 0
+
+
+def install():
+    """Ensure that the mercurial hooks are installed."""
+    hgrc = find_hgrc(create_if_missing=True)
+    if hgrc is None:
+        return False
+
+    hgconfig = configparser_for(hgrc)
+
+    if not hgconfig.has_section('hooks'):
+        hgconfig.add_section('hooks')
+
+    if hgconfig.has_option('hooks', 'commit'):
+        raise exc.MercurialCommitHookAlreadyExists(
+            path=hgrc,
+            value=hgconfig.get('hooks', 'commit'),
+        )
+
+    if hgconfig.has_option('hooks', 'qrefresh'):
+        raise exc.MercurialQRefreshHookAlreadyExists(
+            path=hgrc,
+            value=hgconfig.get('hooks', 'qrefresh'),
+        )
+
+    hgconfig.set('hooks', 'commit', 'python:flake8.main.mercurial.hook')
+    hgconfig.set('hooks', 'qrefresh', 'python:flake8.main.mercurial.hook')
+
+    if not hgconfig.has_section('flake8'):
+        hgconfig.add_section('flake8')
+
+    if not hgconfig.has_option('flake8', 'strict'):
+        hgconfig.set('flake8', 'strict', False)
+
+    with open(hgrc, 'w') as fd:
+        hgconfig.write(fd)
+
+    return True
+
+
+def get_filenames_from(repository, kwargs):
+    seen_filenames = set()
+    node = kwargs['node']
+    for revision in range(repository[node], len(repository)):
+        for filename in repository[revision].files():
+            full_filename = os.path.join(repository.root, filename)
+            have_seen_filename = full_filename in seen_filenames
+            filename_does_not_exist = not os.path.exists(full_filename)
+            if have_seen_filename or filename_does_not_exist:
+                continue
+
+            seen_filenames.add(full_filename)
+            if full_filename.endswith('.py'):
+                yield full_filename
+
+
+def find_hgrc(create_if_missing=False):
+    root = subprocess.Popen(
+        ['hg', 'root'],
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+    )
+
+    (hg_directory, _) = root.communicate()
+    if callable(getattr(hg_directory, 'decode', None)):
+        hg_directory = hg_directory.decode('utf-8')
+
+    if not os.path.isdir(hg_directory):
+        return None
+
+    hgrc = os.path.abspath(
+        os.path.join(hg_directory, '.hg', 'hgrc')
+    )
+    if not os.path.exists(hgrc):
+        if create_if_missing:
+            open(hgrc, 'w').close()
+        else:
+            return None
+
+    return hgrc
+
+
+def configparser_for(path):
+    parser = configparser.ConfigParser(interpolation=None)
+    parser.read(path)
+    return parser
diff --git a/src/flake8/main/options.py b/src/flake8/main/options.py
new file mode 100644
index 0000000..c725c38
--- /dev/null
+++ b/src/flake8/main/options.py
@@ -0,0 +1,201 @@
+"""Contains the logic for all of the default options for Flake8."""
+from flake8 import defaults
+from flake8.main import vcs
+
+
+def register_default_options(option_manager):
+    """Register the default options on our OptionManager.
+
+    The default options include:
+
+    - ``-v``/``--verbose``
+    - ``-q``/``--quiet``
+    - ``--count``
+    - ``--diff``
+    - ``--exclude``
+    - ``--filename``
+    - ``--format``
+    - ``--hang-closing``
+    - ``--ignore``
+    - ``--max-line-length``
+    - ``--select``
+    - ``--disable-noqa``
+    - ``--show-source``
+    - ``--statistics``
+    - ``--enable-extensions``
+    - ``--exit-zero``
+    - ``-j``/``--jobs``
+    - ``--output-file``
+    - ``--append-config``
+    - ``--config``
+    - ``--isolated``
+    """
+    add_option = option_manager.add_option
+
+    # pep8 options
+    add_option(
+        '-v', '--verbose', default=0, action='count',
+        parse_from_config=True,
+        help='Print more information about what is happening in flake8.'
+             ' This option is repeatable and will increase verbosity each '
+             'time it is repeated.',
+    )
+    add_option(
+        '-q', '--quiet', default=0, action='count',
+        parse_from_config=True,
+        help='Report only file names, or nothing. This option is repeatable.',
+    )
+
+    add_option(
+        '--count', action='store_true', parse_from_config=True,
+        help='Print total number of errors and warnings to standard error and'
+             ' set the exit code to 1 if total is not empty.',
+    )
+
+    add_option(
+        '--diff', action='store_true',
+        help='Report changes only within line number ranges in the unified '
+             'diff provided on standard in by the user.',
+    )
+
+    add_option(
+        '--exclude', metavar='patterns', default=defaults.EXCLUDE,
+        comma_separated_list=True, parse_from_config=True,
+        normalize_paths=True,
+        help='Comma-separated list of files or directories to exclude.'
+             ' (Default: %default)',
+    )
+
+    add_option(
+        '--filename', metavar='patterns', default='*.py',
+        parse_from_config=True, comma_separated_list=True,
+        help='Only check for filenames matching the patterns in this comma-'
+             'separated list. (Default: %default)',
+    )
+
+    add_option(
+        '--stdin-display-name', default='stdin',
+        help='The name used when reporting errors from code passed via stdin.'
+             ' This is useful for editors piping the file contents to flake8.'
+             ' (Default: %default)',
+    )
+
+    # TODO(sigmavirus24): Figure out --first/--repeat
+
+    # NOTE(sigmavirus24): We can't use choices for this option since users can
+    # freely provide a format string and that will break if we restrict their
+    # choices.
+    add_option(
+        '--format', metavar='format', default='default',
+        parse_from_config=True,
+        help='Format errors according to the chosen formatter.',
+    )
+
+    add_option(
+        '--hang-closing', action='store_true', parse_from_config=True,
+        help='Hang closing bracket instead of matching indentation of opening'
+             " bracket's line.",
+    )
+
+    add_option(
+        '--ignore', metavar='errors', default=defaults.IGNORE,
+        parse_from_config=True, comma_separated_list=True,
+        help='Comma-separated list of errors and warnings to ignore (or skip).'
+             ' For example, ``--ignore=E4,E51,W234``. (Default: %default)',
+    )
+
+    add_option(
+        '--max-line-length', type='int', metavar='n',
+        default=defaults.MAX_LINE_LENGTH, parse_from_config=True,
+        help='Maximum allowed line length for the entirety of this run. '
+             '(Default: %default)',
+    )
+
+    add_option(
+        '--select', metavar='errors', default=defaults.SELECT,
+        parse_from_config=True, comma_separated_list=True,
+        help='Comma-separated list of errors and warnings to enable.'
+             ' For example, ``--select=E4,E51,W234``. (Default: %default)',
+    )
+
+    add_option(
+        '--disable-noqa', default=False, parse_from_config=True,
+        action='store_true',
+        help='Disable the effect of "# noqa". This will report errors on '
+             'lines with "# noqa" at the end.'
+    )
+
+    # TODO(sigmavirus24): Decide what to do about --show-pep8
+
+    add_option(
+        '--show-source', action='store_true', parse_from_config=True,
+        help='Show the source generate each error or warning.',
+    )
+
+    add_option(
+        '--statistics', action='store_true', parse_from_config=True,
+        help='Count errors and warnings.',
+    )
+
+    # Flake8 options
+    add_option(
+        '--enable-extensions', default='', parse_from_config=True,
+        comma_separated_list=True, type='string',
+        help='Enable plugins and extensions that are otherwise disabled '
+             'by default',
+    )
+
+    add_option(
+        '--exit-zero', action='store_true',
+        help='Exit with status code "0" even if there are errors.',
+    )
+
+    add_option(
+        '--install-hook', action='callback', type='choice',
+        choices=vcs.choices(), callback=vcs.install,
+        help='Install a hook that is run prior to a commit for the supported '
+             'version control systema.'
+    )
+
+    add_option(
+        '-j', '--jobs', type='string', default='auto', parse_from_config=True,
+        help='Number of subprocesses to use to run checks in parallel. '
+             'This is ignored on Windows. The default, "auto", will '
+             'auto-detect the number of processors available to use.'
+             ' (Default: %default)',
+    )
+
+    add_option(
+        '--output-file', default=None, type='string', parse_from_config=True,
+        # callback=callbacks.redirect_stdout,
+        help='Redirect report to a file.',
+    )
+
+    # Config file options
+
+    add_option(
+        '--append-config', action='append',
+        help='Provide extra config files to parse in addition to the files '
+             'found by Flake8 by default. These files are the last ones read '
+             'and so they take the highest precedence when multiple files '
+             'provide the same option.',
+    )
+
+    add_option(
+        '--config', default=None,
+        help='Path to the config file that will be the authoritative config '
+             'source. This will cause Flake8 to ignore all other '
+             'configuration files.'
+    )
+
+    add_option(
+        '--isolated', default=False, action='store_true',
+        help='Ignore all found configuration files.',
+    )
+
+    # Benchmarking
+
+    add_option(
+        '--benchmark', default=False, action='store_true',
+        help='Print benchmark information about this run of Flake8',
+    )
diff --git a/src/flake8/main/setuptools_command.py b/src/flake8/main/setuptools_command.py
new file mode 100644
index 0000000..1c27bf6
--- /dev/null
+++ b/src/flake8/main/setuptools_command.py
@@ -0,0 +1,77 @@
+"""The logic for Flake8's integration with setuptools."""
+import os
+
+import setuptools
+
+from flake8.main import application as app
+
+
+class Flake8(setuptools.Command):
+    """Run Flake8 via setuptools/distutils for registered modules."""
+
+    description = 'Run Flake8 on modules registered in setup.py'
+    # NOTE(sigmavirus24): If we populated this with a list of tuples, users
+    # could do something like ``python setup.py flake8 --ignore=E123,E234``
+    # but we would have to redefine it and we can't define it dynamically.
+    # Since I refuse to copy-and-paste the options here or maintain two lists
+    # of options, and since this will break when users use plugins that
+    # provide command-line options, we are leaving this empty. If users want
+    # to configure this command, they can do so through config files.
+    user_options = []
+
+    def initialize_options(self):
+        """Override this method to initialize our application."""
+        pass
+
+    def finalize_options(self):
+        """Override this to parse the parameters."""
+        pass
+
+    def package_files(self):
+        """Collect the files/dirs included in the registered modules."""
+        seen_package_directories = ()
+        directories = self.distribution.package_dir or {}
+        empty_directory_exists = '' in directories
+        packages = self.distribution.packages or []
+        for package in packages:
+            package_directory = package
+            if package in directories:
+                package_directory = directories[package]
+            elif empty_directory_exists:
+                package_directory = os.path.join(directories[''],
+                                                 package_directory)
+
+            # NOTE(sigmavirus24): Do not collect submodules, e.g.,
+            # if we have:
+            #  - flake8/
+            #  - flake8/plugins/
+            # Flake8 only needs ``flake8/`` to be provided. It will
+            # recurse on its own.
+            if package_directory.startswith(seen_package_directories):
+                continue
+
+            seen_package_directories += (package_directory,)
+            yield package_directory
+
+    def module_files(self):
+        """Collect the files listed as py_modules."""
+        modules = self.distribution.py_modules or []
+        filename_from = '{0}.py'.format
+        for module in modules:
+            yield filename_from(module)
+
+    def distribution_files(self):
+        """Collect package and module files."""
+        for package in self.package_files():
+            yield package
+
+        for module in self.module_files():
+            yield module
+
+        yield 'setup.py'
+
+    def run(self):
+        """Run the Flake8 application."""
+        flake8 = app.Application()
+        flake8.run(list(self.distribution_files()))
+        flake8.exit()
diff --git a/src/flake8/main/vcs.py b/src/flake8/main/vcs.py
new file mode 100644
index 0000000..6f7499e
--- /dev/null
+++ b/src/flake8/main/vcs.py
@@ -0,0 +1,39 @@
+"""Module containing some of the logic for our VCS installation logic."""
+from flake8 import exceptions as exc
+from flake8.main import git
+from flake8.main import mercurial
+
+
+# NOTE(sigmavirus24): In the future, we may allow for VCS hooks to be defined
+# as plugins, e.g., adding a flake8.vcs entry-point. In that case, this
+# dictionary should disappear, and this module might contain more code for
+# managing those bits (in conjuntion with flake8.plugins.manager).
+_INSTALLERS = {
+    'git': git.install,
+    'mercurial': mercurial.install,
+}
+
+
+def install(option, option_string, value, parser):
+    """Determine which version control hook to install.
+
+    For more information about the callback signature, see:
+    https://docs.python.org/2/library/optparse.html#optparse-option-callbacks
+    """
+    installer = _INSTALLERS.get(value)
+    errored = False
+    successful = False
+    try:
+        successful = installer()
+    except exc.HookInstallationError as hook_error:
+        print(str(hook_error))
+        errored = True
+
+    if not successful:
+        print('Could not find the {0} directory'.format(value))
+    raise SystemExit(not successful and errored)
+
+
+def choices():
+    """Return the list of VCS choices."""
+    return list(_INSTALLERS.keys())