setupext.py

from __future__ import print_function, absolute_import

from distutils import sysconfig
from distutils import version
from distutils.core import Extension
import glob
import multiprocessing
import os
import platform
import re
import subprocess
from subprocess import check_output
import sys
import warnings
from textwrap import fill
import shutil
import versioneer


PY3min = (sys.version_info[0] >= 3)
PY32min = (PY3min and sys.version_info[1] >= 2 or sys.version_info[0] > 3)


def _get_home():
    """Find user's home directory if possible.
    Otherwise, returns None.

    :see:
        http://mail.python.org/pipermail/python-list/2005-February/325395.html
    """
    try:
        if not PY3min and sys.platform == 'win32':
            path = os.path.expanduser(b"~").decode(sys.getfilesystemencoding())
        else:
            path = os.path.expanduser("~")
    except ImportError:
        # This happens on Google App Engine (pwd module is not present).
        pass
    else:
        if os.path.isdir(path):
            return path
    for evar in ('HOME', 'USERPROFILE', 'TMP'):
        path = os.environ.get(evar)
        if path is not None and os.path.isdir(path):
            return path
    return None


def _get_xdg_cache_dir():
    """
    Returns the XDG cache directory, according to the `XDG
    base directory spec
    <http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html>`_.
    """
    path = os.environ.get('XDG_CACHE_HOME')
    if path is None:
        path = _get_home()
        if path is not None:
            path = os.path.join(path, '.cache', 'matplotlib')
    return path


# This is the version of FreeType to use when building a local
# version.  It must match the value in
# lib/matplotlib.__init__.py and also needs to be changed below in the
# embedded windows build script (grep for "REMINDER" in this file)
LOCAL_FREETYPE_VERSION = '2.6.1'
# md5 hash of the freetype tarball
LOCAL_FREETYPE_HASH = '348e667d728c597360e4a87c16556597'

if sys.platform != 'win32':
    if not PY3min:
        from commands import getstatusoutput
    else:
        from subprocess import getstatusoutput


if PY3min:
    import configparser
else:
    import ConfigParser as configparser


# matplotlib build options, which can be altered using setup.cfg
options = {
    'display_status': True,
    'verbose': False,
    'backend': None,
    'basedirlist': None
    }


setup_cfg = os.environ.get('MPLSETUPCFG', 'setup.cfg')
if os.path.exists(setup_cfg):
    if PY32min:
        config = configparser.ConfigParser()
    else:
        config = configparser.SafeConfigParser()
    config.read(setup_cfg)

    if config.has_option('status', 'suppress'):
        options['display_status'] = not config.getboolean("status", "suppress")

    if config.has_option('rc_options', 'backend'):
        options['backend'] = config.get("rc_options", "backend")

    if config.has_option('directories', 'basedirlist'):
        options['basedirlist'] = [
            x.strip() for x in
            config.get("directories", "basedirlist").split(',')]

    if config.has_option('test', 'local_freetype'):
        options['local_freetype'] = config.getboolean("test", "local_freetype")
else:
    config = None

lft = bool(os.environ.get('MPLLOCALFREETYPE', False))
options['local_freetype'] = lft or options.get('local_freetype', False)


def get_win32_compiler():
    """
    Determine the compiler being used on win32.
    """
    # Used to determine mingw32 or msvc
    # This is pretty bad logic, someone know a better way?
    for v in sys.argv:
        if 'mingw32' in v:
            return 'mingw32'
    return 'msvc'
win32_compiler = get_win32_compiler()


def extract_versions():
    """
    Extracts version values from the main matplotlib __init__.py and
    returns them as a dictionary.
    """
    with open('lib/matplotlib/__init__.py') as fd:
        for line in fd.readlines():
            if (line.startswith('__version__numpy__')):
                exec(line.strip())
    return locals()


def has_include_file(include_dirs, filename):
    """
    Returns `True` if `filename` can be found in one of the
    directories in `include_dirs`.
    """
    if sys.platform == 'win32':
        include_dirs += os.environ.get('INCLUDE', '.').split(';')
    for dir in include_dirs:
        if os.path.exists(os.path.join(dir, filename)):
            return True
    return False


def check_include_file(include_dirs, filename, package):
    """
    Raises an exception if the given include file can not be found.
    """
    if not has_include_file(include_dirs, filename):
        raise CheckFailed(
            "The C/C++ header for %s (%s) could not be found.  You "
            "may need to install the development package." %
            (package, filename))


def get_base_dirs():
    """
    Returns a list of standard base directories on this platform.
    """
    if options['basedirlist']:
        return options['basedirlist']

    if os.environ.get('MPLBASEDIRLIST'):
        return os.environ.get('MPLBASEDIRLIST').split(os.pathsep)

    win_bases = ['win32_static', ]
    # on conda windows, we also add the <installdir>\Library of the local interpreter,
    # as conda installs libs/includes there
    if os.getenv('CONDA_DEFAULT_ENV'):
        win_bases.append(os.path.join(os.getenv('CONDA_DEFAULT_ENV'), "Library"))

    basedir_map = {
        'win32': win_bases,
        'darwin': ['/usr/local/', '/usr', '/usr/X11',
                   '/opt/X11', '/opt/local'],
        'sunos5': [os.getenv('MPLIB_BASE') or '/usr/local', ],
        'gnu0': ['/usr'],
        'aix5': ['/usr/local'],
        }
    return basedir_map.get(sys.platform, ['/usr/local', '/usr'])


def get_include_dirs():
    """
    Returns a list of standard include directories on this platform.
    """
    include_dirs = [os.path.join(d, 'include') for d in get_base_dirs()]
    if sys.platform != 'win32':
        # gcc includes this dir automatically, so also look for headers in
        # these dirs
        include_dirs.extend(
            os.environ.get('CPLUS_INCLUDE_PATH', '').split(os.pathsep))
    return include_dirs


def is_min_version(found, minversion):
    """
    Returns `True` if `found` is at least as high a version as
    `minversion`.
    """
    expected_version = version.LooseVersion(minversion)
    found_version = version.LooseVersion(found)
    return found_version >= expected_version


# Define the display functions only if display_status is True.
if options['display_status']:
    def print_line(char='='):
        print(char * 76)

    def print_status(package, status):
        initial_indent = "%22s: " % package
        indent = ' ' * 24
        print(fill(str(status), width=76,
                   initial_indent=initial_indent,
                   subsequent_indent=indent))

    def print_message(message):
        indent = ' ' * 24 + "* "
        print(fill(str(message), width=76,
                   initial_indent=indent,
                   subsequent_indent=indent))

    def print_raw(section):
        print(section)
else:
    def print_line(*args, **kwargs):
        pass
    print_status = print_message = print_raw = print_line


# Remove the -Wstrict-prototypesoption, is it's not valid for C++
customize_compiler = sysconfig.customize_compiler


def my_customize_compiler(compiler):
    retval = customize_compiler(compiler)
    try:
        compiler.compiler_so.remove('-Wstrict-prototypes')
    except (ValueError, AttributeError):
        pass
    return retval

sysconfig.customize_compiler = my_customize_compiler


def make_extension(name, files, *args, **kwargs):
    """
    Make a new extension.  Automatically sets include_dirs and
    library_dirs to the base directories appropriate for this
    platform.

    `name` is the name of the extension.

    `files` is a list of source files.

    Any additional arguments are passed to the
    `distutils.core.Extension` constructor.
    """
    ext = DelayedExtension(name, files, *args, **kwargs)
    for dir in get_base_dirs():
        include_dir = os.path.join(dir, 'include')
        if os.path.exists(include_dir):
            ext.include_dirs.append(include_dir)
        for lib in ('lib', 'lib64'):
            lib_dir = os.path.join(dir, lib)
            if os.path.exists(lib_dir):
                ext.library_dirs.append(lib_dir)
    ext.include_dirs.append('.')

    return ext


def get_file_hash(filename):
    """
    Get the MD5 hash of a given filename.
    """
    import hashlib
    BLOCKSIZE = 1 << 16
    hasher = hashlib.md5()
    with open(filename, 'rb') as fd:
        buf = fd.read(BLOCKSIZE)
        while len(buf) > 0:
            hasher.update(buf)
            buf = fd.read(BLOCKSIZE)
    return hasher.hexdigest()


class PkgConfig(object):
    """
    This is a class for communicating with pkg-config.
    """
    def __init__(self):
        """
        Determines whether pkg-config exists on this machine.
        """
        if sys.platform == 'win32':
            self.has_pkgconfig = False
        else:
            try:
                self.pkg_config = os.environ['PKG_CONFIG']
            except KeyError:
                self.pkg_config = 'pkg-config'

            self.set_pkgconfig_path()
            status, output = getstatusoutput(self.pkg_config + " --help")
            self.has_pkgconfig = (status == 0)
            if not self.has_pkgconfig:
                print("IMPORTANT WARNING:")
                print(
                    "    pkg-config is not installed.\n"
                    "    matplotlib may not be able to find some of its dependencies")

    def set_pkgconfig_path(self):
        pkgconfig_path = sysconfig.get_config_var('LIBDIR')
        if pkgconfig_path is None:
            return

        pkgconfig_path = os.path.join(pkgconfig_path, 'pkgconfig')
        if not os.path.isdir(pkgconfig_path):
            return

        try:
            os.environ['PKG_CONFIG_PATH'] += ':' + pkgconfig_path
        except KeyError:
            os.environ['PKG_CONFIG_PATH'] = pkgconfig_path

    def setup_extension(self, ext, package, default_include_dirs=[],
                        default_library_dirs=[], default_libraries=[],
                        alt_exec=None):
        """
        Add parameters to the given `ext` for the given `package`.
        """
        flag_map = {
            '-I': 'include_dirs', '-L': 'library_dirs', '-l': 'libraries'}

        executable = alt_exec
        if self.has_pkgconfig:
            executable = (self.pkg_config + ' {0}').format(package)

        use_defaults = True

        if executable is not None:
            command = "{0} --libs --cflags ".format(executable)

            try:
                output = check_output(command, shell=True,
                                      stderr=subprocess.STDOUT)
            except subprocess.CalledProcessError:
                pass
            else:
                output = output.decode(sys.getfilesystemencoding())
                use_defaults = False
                for token in output.split():
                    attr = flag_map.get(token[:2])
                    if attr is not None:
                        getattr(ext, attr).insert(0, token[2:])

        if use_defaults:
            basedirs = get_base_dirs()
            for base in basedirs:
                for include in default_include_dirs:
                    dir = os.path.join(base, include)
                    if os.path.exists(dir):
                        ext.include_dirs.append(dir)
                for lib in default_library_dirs:
                    dir = os.path.join(base, lib)
                    if os.path.exists(dir):
                        ext.library_dirs.append(dir)
            ext.libraries.extend(default_libraries)
            return True

        return False

    def get_version(self, package):
        """
        Get the version of the package from pkg-config.
        """
        if not self.has_pkgconfig:
            return None

        status, output = getstatusoutput(
            self.pkg_config + " %s --modversion" % (package))
        if status == 0:
            return output
        return None


# The PkgConfig class should be used through this singleton
pkg_config = PkgConfig()


class CheckFailed(Exception):
    """
    Exception thrown when a `SetupPackage.check` method fails.
    """
    pass


class SetupPackage(object):
    optional = False
    pkg_names = {
        "apt-get": None,
        "yum": None,
        "dnf": None,
        "brew": None,
        "port": None,
        "windows_url": None
        }

    def check(self):
        """
        Checks whether the dependencies are met.  Should raise a
        `CheckFailed` exception if the dependency could not be met,
        otherwise return a string indicating a version number or some
        other message indicating what was found.
        """
        pass

    def get_packages(self):
        """
        Get a list of package names to add to the configuration.
        These are added to the `packages` list passed to
        `distutils.setup`.
        """
        return []

    def get_namespace_packages(self):
        """
        Get a list of namespace package names to add to the configuration.
        These are added to the `namespace_packages` list passed to
        `distutils.setup`.
        """
        return []

    def get_py_modules(self):
        """
        Get a list of top-level modules to add to the configuration.
        These are added to the `py_modules` list passed to
        `distutils.setup`.
        """
        return []

    def get_package_data(self):
        """
        Get a package data dictionary to add to the configuration.
        These are merged into to the `package_data` list passed to
        `distutils.setup`.
        """
        return {}

    def get_extension(self):
        """
        Get a list of C extensions (`distutils.core.Extension`
        objects) to add to the configuration.  These are added to the
        `extensions` list passed to `distutils.setup`.
        """
        return None

    def get_install_requires(self):
        """
        Get a list of Python packages that we require.
        pip/easy_install will attempt to download and install this
        package if it is not installed.
        """
        return []

    def get_setup_requires(self):
        """
        Get a list of Python packages that we require at build time.
        pip/easy_install will attempt to download and install this
        package if it is not installed.
        """
        return []

    def _check_for_pkg_config(self, package, include_file, min_version=None,
                              version=None):
        """
        A convenience function for writing checks for a
        pkg_config-defined dependency.

        `package` is the pkg_config package name.

        `include_file` is a top-level include file we expect to find.

        `min_version` is the minimum version required.

        `version` will override the found version if this package
        requires an alternate method for that. Set version='unknown'
        if the version is not known but you still want to disabled
        pkg_config version check.
        """
        if version is None:
            version = pkg_config.get_version(package)

            if version is None:
                raise CheckFailed(
                    "pkg-config information for '%s' could not be found." %
                    package)

        if min_version == 'PATCH':
            raise CheckFailed(
                "Requires patches that have not been merged upstream.")

        if min_version and version != 'unknown':
            if (not is_min_version(version, min_version)):
                raise CheckFailed(
                    "Requires %s %s or later.  Found %s." %
                    (package, min_version, version))

        ext = self.get_extension()
        if ext is None:
            ext = make_extension('test', [])
            pkg_config.setup_extension(ext, package)

        check_include_file(
            ext.include_dirs + get_include_dirs(), include_file, package)

        return 'version %s' % version

    def do_custom_build(self):
        """
        If a package needs to do extra custom things, such as building a
        third-party library, before building an extension, it should
        override this method.
        """
        pass

    def install_help_msg(self):
        """
        Do not override this method !

        Generate the help message to show if the package is not installed.
        To use this in subclasses, simply add the dictionary `pkg_names` as
        a class variable:

        pkg_names = {
            "apt-get": <Name of the apt-get package>,
            "yum": <Name of the yum package>,
            "dnf": <Name of the dnf package>,
            "brew": <Name of the brew package>,
            "port": <Name of the port package>,
            "windows_url": <The url which has installation instructions>
            }

        All the dictionary keys are optional. If a key is not present or has
        the value `None` no message is provided for that platform.
        """
        def _try_managers(*managers):
            for manager in managers:
                pkg_name = self.pkg_names.get(manager, None)
                if pkg_name:
                    try:
                        # `shutil.which()` can be used when Python 2.7 support
                        # is dropped. It is available in Python 3.3+
                        _ = check_output(["which", manager],
                                         stderr=subprocess.STDOUT)
                        return ('Try installing {0} with `{1} install {2}`'
                                .format(self.name, manager, pkg_name))
                    except subprocess.CalledProcessError:
                        pass

        message = None
        if sys.platform == "win32":
            url = self.pkg_names.get("windows_url", None)
            if url:
                message = ('Please check {0} for instructions to install {1}'
                           .format(url, self.name))
        elif sys.platform == "darwin":
            message = _try_managers("brew", "port")
        elif sys.platform.startswith("linux"):
            release = platform.linux_distribution()[0].lower()
            if release in ('debian', 'ubuntu'):
                message = _try_managers('apt-get')
            elif release in ('centos', 'redhat', 'fedora'):
                message = _try_managers('dnf', 'yum')
        return message


class OptionalPackage(SetupPackage):
    optional = True
    force = False
    config_category = "packages"

    @classmethod
    def get_config(cls):
        """
        Look at `setup.cfg` and return one of ["auto", True, False] indicating
        if the package is at default state ("auto"), forced by the user (case
        insensitively defined as 1, true, yes, on for True) or opted-out (case
        insensitively defined as 0, false, no, off for False).
        """
        conf = "auto"
        if config is not None and config.has_option(cls.config_category, cls.name):
            try:
                conf = config.getboolean(cls.config_category, cls.name)
            except ValueError:
                conf = config.get(cls.config_category, cls.name)
        return conf

    def check(self):
        """
        Do not override this method!

        For custom dependency checks override self.check_requirements().
        Two things are checked: Configuration file and requirements.
        """
        # Check configuration file
        conf = self.get_config()
        # Default "auto" state or install forced by user
        if conf in [True, 'auto']:
            message = "installing"
            # Set non-optional if user sets `True` in config
            if conf is True:
                self.optional = False
        # Configuration opt-out by user
        else:
            # Some backend extensions (e.g. Agg) need to be built for certain
            # other GUI backends (e.g. TkAgg) even when manually disabled
            if self.force is True:
                message = "installing forced (config override)"
            else:
                raise CheckFailed("skipping due to configuration")

        # Check requirements and add extra information (if any) to message.
        # If requirements are not met a CheckFailed should be raised in there.
        additional_info = self.check_requirements()
        if additional_info:
            message += ", " + additional_info

        # No CheckFailed raised until now, return install message.
        return message

    def check_requirements(self):
        """
        Override this method to do custom dependency checks.

         - Raise CheckFailed() if requirements are not met.
         - Return message with additional information, or an empty string
           (or None) for no additional information.
        """
        return ""


class OptionalBackendPackage(OptionalPackage):
    config_category = "gui_support"


class Platform(SetupPackage):
    name = "platform"

    def check(self):
        return sys.platform


class Python(SetupPackage):
    name = "python"

    def check(self):
        major, minor1, minor2, s, tmp = sys.version_info

        if major < 2:
            raise CheckFailed(
                "Requires Python 2.7 or later")
        elif major == 2 and minor1 < 7:
            raise CheckFailed(
                "Requires Python 2.7 or later (in the 2.x series)")
        elif major == 3 and minor1 < 4:
            raise CheckFailed(
                "Requires Python 3.4 or later (in the 3.x series)")

        return sys.version


class Matplotlib(SetupPackage):
    name = "matplotlib"

    def check(self):
        return versioneer.get_version()

    def get_packages(self):
        return [
            'matplotlib',
            'matplotlib.backends',
            'matplotlib.backends.qt_editor',
            'matplotlib.compat',
            'matplotlib.projections',
            'matplotlib.axes',
            'matplotlib.sphinxext',
            'matplotlib.style',
            'matplotlib.testing',
            'matplotlib.testing.jpl_units',
            'matplotlib.tri',
            ]

    def get_py_modules(self):
        return ['pylab']

    def get_package_data(self):
        return {
            'matplotlib':
            [
                'mpl-data/fonts/afm/*.afm',
                'mpl-data/fonts/pdfcorefonts/*.afm',
                'mpl-data/fonts/pdfcorefonts/*.txt',
                'mpl-data/fonts/ttf/*.ttf',
                'mpl-data/fonts/ttf/LICENSE_STIX',
                'mpl-data/fonts/ttf/COPYRIGHT.TXT',
                'mpl-data/fonts/ttf/README.TXT',
                'mpl-data/fonts/ttf/RELEASENOTES.TXT',
                'mpl-data/images/*.xpm',
                'mpl-data/images/*.svg',
                'mpl-data/images/*.gif',
                'mpl-data/images/*.pdf',
                'mpl-data/images/*.png',
                'mpl-data/images/*.ppm',
                'mpl-data/example/*.npy',
                'mpl-data/matplotlibrc',
                'backends/web_backend/*.*',
                'backends/web_backend/jquery/js/*.min.js',
                'backends/web_backend/jquery/css/themes/base/*.min.css',
                'backends/web_backend/jquery/css/themes/base/images/*',
                'backends/web_backend/css/*.*',
                'backends/web_backend/js/*.js',
                'backends/Matplotlib.nib/*',
                'mpl-data/stylelib/*.mplstyle',
             ]}


class SampleData(OptionalPackage):
    """
    This handles the sample data that ships with matplotlib.  It is
    technically optional, though most often will be desired.
    """
    name = "sample_data"

    def get_package_data(self):
        return {
            'matplotlib':
            [
                'mpl-data/sample_data/*.*',
                'mpl-data/sample_data/axes_grid/*.*',
            ]}


class Toolkits(OptionalPackage):
    name = "toolkits"

    def get_packages(self):
        return [
            'mpl_toolkits',
            'mpl_toolkits.mplot3d',
            'mpl_toolkits.axes_grid',
            'mpl_toolkits.axes_grid1',
            'mpl_toolkits.axisartist',
            ]

    def get_namespace_packages(self):
        return ['mpl_toolkits']


class Tests(OptionalPackage):
    name = "tests"
    nose_min_version = '0.11.1'

    def check(self):
        super(Tests, self).check()

        msgs = []
        msg_template = ('{package} is required to run the matplotlib test '
                        'suite. Please install it with pip or your preferred'
                        ' tool to run the test suite')

        bad_nose = msg_template.format(
            package='nose %s or later' % self.nose_min_version
        )
        try:
            import nose
            if is_min_version(nose.__version__, self.nose_min_version):
                msgs += ['using nose version %s' % nose.__version__]
            else:
                msgs += [bad_nose]
        except ImportError:
            msgs += [bad_nose]

        if sys.version_info >= (3, 3):
            msgs += ['using unittest.mock']
        else:
            try:
                import mock
                msgs += ['using mock %s' % mock.__version__]
            except ImportError:
                msgs += [msg_template.format(package='mock')]

        return ' / '.join(msgs)

    def get_packages(self):
        return [
            'matplotlib.tests',
            'matplotlib.sphinxext.tests',
            ]

    def get_package_data(self):
        baseline_images = [
            'tests/baseline_images/%s/*' % x
            for x in os.listdir('lib/matplotlib/tests/baseline_images')]

        return {
            'matplotlib':
            baseline_images +
            [
                'tests/cmr10.pfb',
                'tests/mpltest.ttf',
                'tests/test_rcparams.rc',
                'tests/test_utf32_be_rcparams.rc',
                'sphinxext/tests/tinypages/*.rst',
                'sphinxext/tests/tinypages/*.py',
                'sphinxext/tests/tinypages/_static/*',
            ]}


class Toolkits_Tests(Tests):
    name = "toolkits_tests"

    def check_requirements(self):
        conf = self.get_config()
        toolkits_conf = Toolkits.get_config()
        tests_conf = Tests.get_config()

        if conf is True:
            Tests.force = True
            Toolkits.force = True
        elif conf == "auto" and not (toolkits_conf and tests_conf):
            # Only auto-install if both toolkits and tests are set
            # to be installed
            raise CheckFailed("toolkits_tests needs 'toolkits' and 'tests'")
        return ""

    def get_packages(self):
        return [
            'mpl_toolkits.tests',
            ]

    def get_package_data(self):
        baseline_images = [
            'tests/baseline_images/%s/*' % x
            for x in os.listdir('lib/mpl_toolkits/tests/baseline_images')]

        return {'mpl_toolkits': baseline_images}

    def get_namespace_packages(self):
        return ['mpl_toolkits']


class DelayedExtension(Extension, object):
    """
    A distutils Extension subclass where some of its members
    may have delayed computation until reaching the build phase.

    This is so we can, for example, get the Numpy include dirs
    after pip has installed Numpy for us if it wasn't already
    on the system.
    """
    def __init__(self, *args, **kwargs):
        super(DelayedExtension, self).__init__(*args, **kwargs)
        self._finalized = False
        self._hooks = {}

    def add_hook(self, member, func):
        """
        Add a hook to dynamically compute a member.

        Parameters
        ----------
        member : string
            The name of the member

        func : callable
            The function to call to get dynamically-computed values
            for the member.
        """
        self._hooks[member] = func

    def finalize(self):
        self._finalized = True

    class DelayedMember(property):
        def __init__(self, name):
            self._name = name

        def __get__(self, obj, objtype=None):
            result = getattr(obj, '_' + self._name, [])

            if obj._finalized:
                if self._name in obj._hooks:
                    result = obj._hooks[self._name]() + result

            return result

        def __set__(self, obj, value):
            setattr(obj, '_' + self._name, value)

    include_dirs = DelayedMember('include_dirs')


class Numpy(SetupPackage):
    name = "numpy"

    @staticmethod
    def include_dirs_hook():
        if sys.version_info[0] >= 3:
            import builtins
            if hasattr(builtins, '__NUMPY_SETUP__'):
                del builtins.__NUMPY_SETUP__
            import imp
            import numpy
            imp.reload(numpy)
        else:
            import __builtin__
            if hasattr(__builtin__, '__NUMPY_SETUP__'):
                del __builtin__.__NUMPY_SETUP__
            import numpy
            reload(numpy)

        ext = Extension('test', [])
        ext.include_dirs.append(numpy.get_include())
        if not has_include_file(
                ext.include_dirs, os.path.join("numpy", "arrayobject.h")):
            warnings.warn(
                "The C headers for numpy could not be found. "
                "You may need to install the development package")

        return [numpy.get_include()]

    def check(self):
        min_version = extract_versions()['__version__numpy__']
        try:
            import numpy
        except ImportError:
            return 'not found. pip may install it below.'

        if not is_min_version(numpy.__version__, min_version):
            raise SystemExit(
                "Requires numpy %s or later to build.  (Found %s)" %
                (min_version, numpy.__version__))

        return 'version %s' % numpy.__version__

    def add_flags(self, ext):
        # Ensure that PY_ARRAY_UNIQUE_SYMBOL is uniquely defined for
        # each extension
        array_api_name = 'MPL_' + ext.name.replace('.', '_') + '_ARRAY_API'

        ext.define_macros.append(('PY_ARRAY_UNIQUE_SYMBOL', array_api_name))
        ext.add_hook('include_dirs', self.include_dirs_hook)

        ext.define_macros.append(('NPY_NO_DEPRECATED_API',
                                  'NPY_1_7_API_VERSION'))

    def get_setup_requires(self):
        return ['numpy>=1.6']

    def get_install_requires(self):
        return ['numpy>=1.6']


class LibAgg(SetupPackage):
    name = 'libagg'

    def check(self):
        self.__class__.found_external = True
        try:
            return self._check_for_pkg_config(
                'libagg', 'agg2/agg_basics.h', min_version='PATCH')
        except CheckFailed as e:
            self.__class__.found_external = False
            return str(e) + ' Using local copy.'

    def add_flags(self, ext, add_sources=True):
        if self.found_external:
            pkg_config.setup_extension(ext, 'libagg')
        else:
            ext.include_dirs.append('extern/agg24-svn/include')
            if add_sources:
                agg_sources = [
                    'agg_bezier_arc.cpp',
                    'agg_curves.cpp',
                    'agg_image_filters.cpp',
                    'agg_trans_affine.cpp',
                    'agg_vcgen_contour.cpp',
                    'agg_vcgen_dash.cpp',
                    'agg_vcgen_stroke.cpp',
                    'agg_vpgen_segmentator.cpp'
                    ]
                ext.sources.extend(
                    os.path.join('extern', 'agg24-svn', 'src', x) for x in agg_sources)


class FreeType(SetupPackage):
    name = "freetype"
    pkg_names = {
        "apt-get": "libfreetype6-dev",
        "yum": "freetype-devel",
        "dnf": "freetype-devel",
        "brew": "freetype",
        "port": "freetype",
        "windows_url": "http://gnuwin32.sourceforge.net/packages/freetype.htm"
        }

    def check(self):
        if options.get('local_freetype'):
            return "Using local version for testing"

        if sys.platform == 'win32':
            try:
                check_include_file(get_include_dirs(), 'ft2build.h', 'freetype')
            except CheckFailed:
                check_include_file(get_include_dirs(), 'freetype2\\ft2build.h', 'freetype')
            return 'Using unknown version found on system.'

        status, output = getstatusoutput("freetype-config --ftversion")
        if status == 0:
            version = output
        else:
            version = None

        # Early versions of freetype grep badly inside freetype-config,
        # so catch those cases. (tested with 2.5.3).
        if version is None or 'No such file or directory\ngrep:' in version:
            version = self.version_from_header()

        # pkg_config returns the libtool version rather than the
        # freetype version so we need to explicitly pass the version
        # to _check_for_pkg_config
        return self._check_for_pkg_config(
            'freetype2', 'ft2build.h',
            min_version='2.3', version=version)

    def version_from_header(self):
        version = 'unknown'
        ext = self.get_extension()
        if ext is None:
            return version
        # Return the first version found in the include dirs.
        for include_dir in ext.include_dirs:
            header_fname = os.path.join(include_dir, 'freetype.h')
            if os.path.exists(header_fname):
                major, minor, patch = 0, 0, 0
                with open(header_fname, 'r') as fh:
                    for line in fh:
                        if line.startswith('#define FREETYPE_'):
                            value = line.rsplit(' ', 1)[1].strip()
                            if 'MAJOR' in line:
                                major = value
                            elif 'MINOR' in line:
                                minor = value
                            else:
                                patch = value
                return '.'.join([major, minor, patch])

    def add_flags(self, ext):
        if options.get('local_freetype'):
            src_path = os.path.join(
                'build', 'freetype-{0}'.format(LOCAL_FREETYPE_VERSION))
            # Statically link to the locally-built freetype.
            # This is certainly broken on Windows.
            ext.include_dirs.insert(0, os.path.join(src_path, 'include'))
            if sys.platform == 'win32':
                libfreetype = 'libfreetype.lib'
            else:
                libfreetype = 'libfreetype.a'
            ext.extra_objects.insert(
                0, os.path.join(src_path, 'objs', '.libs', libfreetype))
            ext.define_macros.append(('FREETYPE_BUILD_TYPE', 'local'))
        else:
            pkg_config.setup_extension(
                ext, 'freetype2',
                default_include_dirs=[
                    'include/freetype2', 'freetype2',
                    'lib/freetype2/include',
                    'lib/freetype2/include/freetype2'],
                default_library_dirs=[
                    'freetype2/lib'],
                default_libraries=['freetype', 'z'])
            ext.define_macros.append(('FREETYPE_BUILD_TYPE', 'system'))

    def do_custom_build(self):
        # We're using a system freetype
        if not options.get('local_freetype'):
            return

        src_path = os.path.join(
            'build', 'freetype-{0}'.format(LOCAL_FREETYPE_VERSION))

        # We've already built freetype
        if sys.platform == 'win32':
            libfreetype = 'libfreetype.lib'
        else:
            libfreetype = 'libfreetype.a'

        if os.path.isfile(os.path.join(src_path, 'objs', '.libs', libfreetype)):
            return

        tarball = 'freetype-{0}.tar.gz'.format(LOCAL_FREETYPE_VERSION)
        tarball_path = os.path.join('build', tarball)
        try:
            tarball_cache_dir = _get_xdg_cache_dir()
            tarball_cache_path = os.path.join(tarball_cache_dir, tarball)
        except:
            # again, do not really care if this fails
            tarball_cache_dir = None
            tarball_cache_path = None
        if not os.path.isfile(tarball_path):
            if (tarball_cache_path is not None and
                    os.path.isfile(tarball_cache_path)):
                if get_file_hash(tarball_cache_path) == LOCAL_FREETYPE_HASH:
                    try:
                        # fail on Lpy, oh well
                        os.makedirs('build', exist_ok=True)
                        shutil.copy(tarball_cache_path, tarball_path)
                        print('Using cached tarball: {}'
                              .format(tarball_cache_path))
                    except:
                        # If this fails, oh well just re-download
                        pass

            if not os.path.isfile(tarball_path):
                url_fmt = (
                    'http://download.savannah.gnu.org/releases/freetype/{0}')
                tarball_url = url_fmt.format(tarball)

                print("Downloading {0}".format(tarball_url))
                if sys.version_info[0] == 2:
                    from urllib import urlretrieve
                else:
                    from urllib.request import urlretrieve

                if not os.path.exists('build'):
                    os.makedirs('build')
                urlretrieve(tarball_url, tarball_path)
                if get_file_hash(tarball_path) == LOCAL_FREETYPE_HASH:
                    try:
                        # this will fail on LPy, oh well
                        os.makedirs(tarball_cache_dir, exist_ok=True)
                        shutil.copy(tarball_path, tarball_cache_path)
                        print('Cached tarball at: {}'
                              .format(tarball_cache_path))
                    except:
                        # again, we do not care if this fails, can
                        # always re download
                        pass

            if get_file_hash(tarball_path) != LOCAL_FREETYPE_HASH:
                raise IOError(
                    "{0} does not match expected hash.".format(tarball))

        print("Building {0}".format(tarball))
        if sys.platform != 'win32':
            # compilation on all other platforms than windows
            cflags = 'CFLAGS="{0} -fPIC" '.format(os.environ.get('CFLAGS', ''))

            subprocess.check_call(
                ['tar', 'zxf', tarball], cwd='build')
            subprocess.check_call(
                [cflags + './configure --with-zlib=no --with-bzip2=no '
                 '--with-png=no --with-harfbuzz=no'], shell=True, cwd=src_path)
            subprocess.check_call(
                [cflags + 'make'], shell=True, cwd=src_path)
        else:
            # compilation on windows
            FREETYPE_BUILD_CMD = """\
call "%ProgramFiles%\\Microsoft SDKs\\Windows\\v7.0\\Bin\\SetEnv.Cmd" /Release /{xXX} /xp
call "{vcvarsall}" {xXX}
set MSBUILD=C:\\Windows\\Microsoft.NET\\Framework\\v4.0.30319\\MSBuild.exe
rd /S /Q %FREETYPE%\\objs
%MSBUILD% %FREETYPE%\\builds\\windows\\{vc20xx}\\freetype.sln /t:Clean;Build /p:Configuration="{config}";Platform={WinXX}
echo Build completed, moving result"
:: move to the "normal" path for the unix builds...
mkdir %FREETYPE%\\objs\\.libs
:: REMINDER: fix when changing the version
copy %FREETYPE%\\objs\\{vc20xx}\\{xXX}\\freetype261.lib %FREETYPE%\\objs\\.libs\\libfreetype.lib
if errorlevel 1 (
  rem This is a py27 version, which has a different location for the lib file :-/
  copy %FREETYPE%\\objs\\win32\\{vc20xx}\\freetype261.lib %FREETYPE%\\objs\\.libs\\libfreetype.lib
)
"""
            from setup_external_compile import fixproj, prepare_build_cmd, VS2010, X64, tar_extract
            # Note: freetype has no build profile for 2014, so we don't bother...
            vc = 'vc2010' if VS2010 else 'vc2008'
            WinXX = 'x64' if X64 else 'Win32'
            tar_extract(tarball_path, "build")
            # This is only false for py2.7, even on py3.5...
            if not VS2010:
                fixproj(os.path.join(src_path, 'builds', 'windows', vc, 'freetype.sln'), WinXX)
                fixproj(os.path.join(src_path, 'builds', 'windows', vc, 'freetype.vcproj'), WinXX)

            cmdfile = os.path.join("build", 'build_freetype.cmd')
            with open(cmdfile, 'w') as cmd:
                cmd.write(prepare_build_cmd(FREETYPE_BUILD_CMD, vc20xx=vc, WinXX=WinXX,
                                            config='Release' if VS2010 else 'LIB Release'))

            os.environ['FREETYPE'] = src_path
            subprocess.check_call([cmdfile], shell=True)


class FT2Font(SetupPackage):
    name = 'ft2font'

    def get_extension(self):
        sources = [
            'src/ft2font.cpp',
            'src/ft2font_wrapper.cpp',
            'src/mplutils.cpp'
            ]
        ext = make_extension('matplotlib.ft2font', sources)
        FreeType().add_flags(ext)
        Numpy().add_flags(ext)
        return ext


class Png(SetupPackage):
    name = "png"
    pkg_names = {
        "apt-get": "libpng12-dev",
        "yum": "libpng-devel",
        "dnf": "libpng-devel",
        "brew": "libpng",
        "port": "libpng",
        "windows_url": "http://gnuwin32.sourceforge.net/packages/libpng.htm"
        }

    def check(self):
        if sys.platform == 'win32':
            check_include_file(get_include_dirs(), 'png.h', 'png')
            return 'Using unknown version found on system.'

        status, output = getstatusoutput("libpng-config --version")
        if status == 0:
            version = output
        else:
            version = None

        try:
            return self._check_for_pkg_config(
                'libpng', 'png.h',
                min_version='1.2', version=version)
        except CheckFailed as e:
            if has_include_file(get_include_dirs(), 'png.h'):
                return str(e) + ' Using unknown version found on system.'
            raise

    def get_extension(self):
        sources = [
            'src/_png.cpp',
            'src/mplutils.cpp'
            ]
        ext = make_extension('matplotlib._png', sources)
        pkg_config.setup_extension(
            ext, 'libpng', default_libraries=['png', 'z'],
            alt_exec='libpng-config --ldflags')
        Numpy().add_flags(ext)
        return ext


class Qhull(SetupPackage):
    name = "qhull"

    def check(self):
        self.__class__.found_external = True
        try:
            return self._check_for_pkg_config(
                'qhull', 'qhull/qhull_a.h', min_version='2003.1')
        except CheckFailed as e:
            self.__class__.found_pkgconfig = False
            # Qhull may not be in the pkg-config system but may still be
            # present on this system, so check if the header files can be
            # found.
            include_dirs = [
                os.path.join(x, 'qhull') for x in get_include_dirs()]
            if has_include_file(include_dirs, 'qhull_a.h'):
                return 'Using system Qhull (version unknown, no pkg-config info)'
            else:
                self.__class__.found_external = False
                return str(e) + ' Using local copy.'

    def add_flags(self, ext):
        if self.found_external:
            pkg_config.setup_extension(ext, 'qhull',
                                       default_libraries=['qhull'])
        else:
            ext.include_dirs.append('extern')
            ext.sources.extend(glob.glob('extern/qhull/*.c'))


class TTConv(SetupPackage):
    name = "ttconv"

    def get_extension(self):
        sources = [
            'src/_ttconv.cpp',
            'extern/ttconv/pprdrv_tt.cpp',
            'extern/ttconv/pprdrv_tt2.cpp',
            'extern/ttconv/ttutil.cpp'
            ]
        ext = make_extension('matplotlib.ttconv', sources)
        Numpy().add_flags(ext)
        ext.include_dirs.append('extern')
        return ext


class Path(SetupPackage):
    name = "path"

    def get_extension(self):
        sources = [
            'src/py_converters.cpp',
            'src/_path_wrapper.cpp'
            ]

        ext = make_extension('matplotlib._path', sources)
        Numpy().add_flags(ext)
        LibAgg().add_flags(ext)
        return ext


class Image(SetupPackage):
    name = "image"

    def get_extension(self):
        sources = [
            'src/_image.cpp',
            'src/mplutils.cpp',
            'src/_image_wrapper.cpp',
            'src/py_converters.cpp'
            ]
        ext = make_extension('matplotlib._image', sources)
        Numpy().add_flags(ext)
        LibAgg().add_flags(ext)

        return ext


class ContourLegacy(SetupPackage):
    name = "contour_legacy"

    def get_extension(self):
        sources = [
            "src/cntr.c"
            ]
        ext = make_extension('matplotlib._cntr', sources)
        Numpy().add_flags(ext)
        return ext


class Contour(SetupPackage):
    name = "contour"

    def get_extension(self):
        sources = [
            "src/_contour.cpp",
            "src/_contour_wrapper.cpp",
            ]
        ext = make_extension('matplotlib._contour', sources)
        Numpy().add_flags(ext)
        return ext


class Delaunay(SetupPackage):
    name = "delaunay"

    def get_packages(self):
        return ['matplotlib.delaunay']

    def get_extension(self):
        sources = ["_delaunay.cpp", "VoronoiDiagramGenerator.cpp",
                   "delaunay_utils.cpp", "natneighbors.cpp"]
        sources = [os.path.join('lib/matplotlib/delaunay', s) for s in sources]
        ext = make_extension('matplotlib._delaunay', sources)
        Numpy().add_flags(ext)
        return ext


class QhullWrap(SetupPackage):
    name = "qhull_wrap"

    def get_extension(self):
        sources = ['src/qhull_wrap.c']
        ext = make_extension('matplotlib._qhull', sources,
                             define_macros=[('MPL_DEVNULL', os.devnull)])
        Numpy().add_flags(ext)
        Qhull().add_flags(ext)
        return ext


class Tri(SetupPackage):
    name = "tri"

    def get_extension(self):
        sources = [
            "lib/matplotlib/tri/_tri.cpp",
            "lib/matplotlib/tri/_tri_wrapper.cpp",
            "src/mplutils.cpp"
            ]
        ext = make_extension('matplotlib._tri', sources)
        Numpy().add_flags(ext)
        return ext


class Six(SetupPackage):
    name = "six"
    min_version = "1.10"

    def check(self):
        try:
            import six
        except ImportError:
            return (
                "six was not found."
                "pip will attempt to install it "
                "after matplotlib.")

        if not is_min_version(six.__version__, self.min_version):
            return ("The installed version of six is {inst_ver} but "
                    "a the minimum required version is {min_ver}. "
                    "pip/easy install will attempt to install a "
                    "newer version."
                    ).format(min_ver=self.min_version,
                             inst_ver=six.__version__)

        return "using six version %s" % six.__version__

    def get_install_requires(self):
        return ['six>={0}'.format(self.min_version)]


class Pytz(SetupPackage):
    name = "pytz"

    def check(self):
        try:
            import pytz
        except ImportError:
            return (
                "pytz was not found. "
                "pip/easy_install may attempt to install it "
                "after matplotlib.")

        return "using pytz version %s" % pytz.__version__

    def get_install_requires(self):
        return ['pytz']


class Cycler(SetupPackage):
    name = "cycler"

    def check(self):
        try:
            import cycler
        except ImportError:
            return (
                "cycler was not found. "
                "pip/easy_install may attempt to install it "
                "after matplotlib.")
        return "using cycler version %s" % cycler.__version__

    def get_install_requires(self):
        return ['cycler>=0.10']


class Dateutil(SetupPackage):
    name = "dateutil"

    def __init__(self, version=None):
        self.version = version

    def check(self):
        try:
            import dateutil
        except ImportError:
            # dateutil 2.1 has a file encoding bug that breaks installation on
            # python 3.3
            # https://github.com/matplotlib/matplotlib/issues/2373
            # hack around the problem by installing the (working) v2.0
            major, minor1, _, _, _ = sys.version_info
            if self.version is None and (major, minor1) == (3, 3):
                self.version = '!=2.1'

            return (
                "dateutil was not found. It is required for date axis "
                "support. pip/easy_install may attempt to install it "
                "after matplotlib.")

        return "using dateutil version %s" % dateutil.__version__

    def get_install_requires(self):
        dateutil = 'python-dateutil'
        if self.version is not None:
            dateutil += self.version
        return [dateutil]


class FuncTools32(SetupPackage):
    name = "functools32"

    def check(self):
        if sys.version_info[:2] < (3, 2):
            try:
                import functools32
            except ImportError:
                return (
                    "functools32 was not found. It is required for"
                    "Python versions prior to 3.2")

            return "using functools32"
        else:
            return "Not required"

    def get_install_requires(self):
        if sys.version_info[:2] < (3, 2):
            return ['functools32']
        else:
            return []


class Subprocess32(SetupPackage):
    name = "subprocess32"

    def check(self):
        if sys.version_info[:2] < (3, 2):
            try:
                import subprocess32
            except ImportError:
                return (
                    "subprocess32 was not found. It used "
                    " for Python versions prior to 3.2 to improves"
                    " functionality on Linux and OSX")

            return "using subprocess32"
        else:
            return "Not required"

    def get_install_requires(self):
        if sys.version_info[:2] < (3, 2) and os.name == 'posix':
            return ['subprocess32']
        else:
            return []


class Tornado(OptionalPackage):
    name = "tornado"

    def check(self):
        try:
            import tornado
        except ImportError:
            return (
                "tornado was not found. It is required for the WebAgg "
                "backend. pip/easy_install may attempt to install it "
                "after matplotlib.")

        return "using tornado version %s" % tornado.version


class Pyparsing(SetupPackage):
    name = "pyparsing"
    # pyparsing 2.0.4 has broken python 3 support.
    # pyparsing 2.1.2 is broken in python3.4/3.3.
    def is_ok(self):
        # pyparsing 2.0.0 bug, but it may be patched in distributions
        try:
            import pyparsing
            f = pyparsing.Forward()
            f <<= pyparsing.Literal('a')
            return f is not None
        except (ImportError, TypeError):
            return False

    def check(self):
        try:
            import pyparsing
        except ImportError:
            return (
                "pyparsing was not found. It is required for mathtext "
                "support. pip/easy_install may attempt to install it "
                "after matplotlib.")

        required = [1, 5, 6]
        if [int(x) for x in pyparsing.__version__.split('.')] < required:
            return (
                "matplotlib requires pyparsing >= {0}".format(
                    '.'.join(str(x) for x in required)))

        if not self.is_ok():
            return (
                "Your pyparsing contains a bug that will be monkey-patched by "
                "matplotlib.  For best results, upgrade to pyparsing 2.0.1 or "
                "later.")

        return "using pyparsing version %s" % pyparsing.__version__

    def get_install_requires(self):
        versionstring = 'pyparsing>=1.5.6,!=2.0.4,!=2.1.2'
        if self.is_ok():
            return [versionstring]
        else:
            return [versionstring + ',!=2.0.0']


class BackendAgg(OptionalBackendPackage):
    name = "agg"
    force = True

    def get_extension(self):
        sources = [
            "src/mplutils.cpp",
            "src/py_converters.cpp",
            "src/_backend_agg.cpp",
            "src/_backend_agg_wrapper.cpp"
            ]
        ext = make_extension('matplotlib.backends._backend_agg', sources)
        Numpy().add_flags(ext)
        LibAgg().add_flags(ext)
        FreeType().add_flags(ext)
        return ext


class BackendTkAgg(OptionalBackendPackage):
    name = "tkagg"
    force = True

    def check(self):
        return "installing; run-time loading from Python Tcl / Tk"

    def get_extension(self):
        sources = [
            'src/py_converters.cpp',
            'src/_tkagg.cpp'
            ]

        ext = make_extension('matplotlib.backends._tkagg', sources)
        self.add_flags(ext)
        Numpy().add_flags(ext)
        LibAgg().add_flags(ext, add_sources=False)
        return ext

    def add_flags(self, ext):
        ext.include_dirs.extend(['src'])
        if sys.platform == 'win32':
            # PSAPI library needed for finding Tcl / Tk at run time
            ext.libraries.extend(['psapi'])


class BackendGtk(OptionalBackendPackage):
    name = "gtk"

    def check_requirements(self):
        try:
            import gtk
        except ImportError:
            raise CheckFailed("Requires pygtk")
        except RuntimeError:
            raise CheckFailed('pygtk present, but import failed.')
        else:
            version = (2, 2, 0)
            if gtk.pygtk_version < version:
                raise CheckFailed(
                    "Requires pygtk %d.%d.%d or later. "
                    "Found %d.%d.%d" % (version + gtk.pygtk_version))

        ext = self.get_extension()
        self.add_flags(ext)
        check_include_file(ext.include_dirs,
                           os.path.join("gtk", "gtk.h"),
                           'gtk')
        check_include_file(ext.include_dirs,
                           os.path.join("pygtk", "pygtk.h"),
                           'pygtk')

        return 'Gtk: %s pygtk: %s' % (
            ".".join(str(x) for x in gtk.gtk_version),
            ".".join(str(x) for x in gtk.pygtk_version))

    def get_package_data(self):
        return {'matplotlib': ['mpl-data/*.glade']}

    def get_extension(self):
        sources = [
            'src/_backend_gdk.c'
            ]
        ext = make_extension('matplotlib.backends._backend_gdk', sources)
        self.add_flags(ext)
        Numpy().add_flags(ext)
        return ext

    def add_flags(self, ext):
        if sys.platform == 'win32':
            def getoutput(s):
                ret = os.popen(s).read().strip()
                return ret

            if 'PKG_CONFIG_PATH' not in os.environ:
                # If Gtk+ is installed, pkg-config is required to be installed
                os.environ['PKG_CONFIG_PATH'] = 'C:\\GTK\\lib\\pkgconfig'

                # popen broken on my win32 plaform so I can't use pkgconfig
                ext.library_dirs.extend(
                    ['C:/GTK/bin', 'C:/GTK/lib'])

                ext.include_dirs.extend(
                    ['win32_static/include/pygtk-2.0',
                     'C:/GTK/include',
                     'C:/GTK/include/gobject',
                     'C:/GTK/include/gext',
                     'C:/GTK/include/glib',
                     'C:/GTK/include/pango',
                     'C:/GTK/include/atk',
                     'C:/GTK/include/X11',
                     'C:/GTK/include/cairo',
                     'C:/GTK/include/gdk',
                     'C:/GTK/include/gdk-pixbuf',
                     'C:/GTK/include/gtk',
                     ])

            pygtkIncludes = getoutput(
                'pkg-config --cflags-only-I pygtk-2.0').split()
            gtkIncludes = getoutput(
                'pkg-config --cflags-only-I gtk+-2.0').split()
            includes = pygtkIncludes + gtkIncludes
            ext.include_dirs.extend([include[2:] for include in includes])

            pygtkLinker = getoutput('pkg-config --libs pygtk-2.0').split()
            gtkLinker = getoutput('pkg-config --libs gtk+-2.0').split()
            linkerFlags = pygtkLinker + gtkLinker

            ext.libraries.extend(
                [flag[2:] for flag in linkerFlags if flag.startswith('-l')])

            ext.library_dirs.extend(
                [flag[2:] for flag in linkerFlags if flag.startswith('-L')])

            ext.extra_link_args.extend(
                [flag for flag in linkerFlags if not
                 (flag.startswith('-l') or flag.startswith('-L'))])

            # visual studio doesn't need the math library
            if (sys.platform == 'win32' and
                win32_compiler == 'msvc' and
                'm' in ext.libraries):
                ext.libraries.remove('m')

        elif sys.platform != 'win32':
            pkg_config.setup_extension(ext, 'pygtk-2.0')
            pkg_config.setup_extension(ext, 'gtk+-2.0')


class BackendGtkAgg(BackendGtk):
    name = "gtkagg"

    def check(self):
        try:
            return super(BackendGtkAgg, self).check()
        except:
            raise

    def get_package_data(self):
        return {'matplotlib': ['mpl-data/*.glade']}

    def get_extension(self):
        sources = [
            'src/py_converters.cpp',
            'src/_gtkagg.cpp',
            'src/mplutils.cpp'
            ]
        ext = make_extension('matplotlib.backends._gtkagg', sources)
        self.add_flags(ext)
        LibAgg().add_flags(ext)
        Numpy().add_flags(ext)
        return ext


def backend_gtk3agg_internal_check(x):
    try:
        import gi
    except ImportError:
        return (False, "Requires pygobject to be installed.")

    try:
        gi.require_version("Gtk", "3.0")
    except ValueError:
        return (False, "Requires gtk3 development files to be installed.")
    except AttributeError:
        return (False, "pygobject version too old.")

    try:
        from gi.repository import Gtk, Gdk, GObject
    except (ImportError, RuntimeError):
        return (False, "Requires pygobject to be installed.")

    return (True, "version %s.%s.%s" % (
        Gtk.get_major_version(),
        Gtk.get_micro_version(),
        Gtk.get_minor_version()))


class BackendGtk3Agg(OptionalBackendPackage):
    name = "gtk3agg"

    def check_requirements(self):
        if 'TRAVIS' in os.environ:
            raise CheckFailed("Can't build with Travis")

        # This check needs to be performed out-of-process, because
        # importing gi and then importing regular old pygtk afterward
        # segfaults the interpreter.
        try:
            p = multiprocessing.Pool()
        except:
            return "unknown (can not use multiprocessing to determine)"
        try:
            res = p.map_async(backend_gtk3agg_internal_check, [0])
            success, msg = res.get(timeout=10)[0]
        except multiprocessing.TimeoutError:
            p.terminate()
            # No result returned. Probaly hanging, terminate the process.
            success = False
            raise CheckFailed("Check timed out")
        except:
            p.close()
            # Some other error.
            success = False
            msg = "Could not determine"
            raise
        else:
            p.close()
        finally:
            p.join()

        if success:
            return msg
        else:
            raise CheckFailed(msg)

    def get_package_data(self):
        return {'matplotlib': ['mpl-data/*.glade']}


def backend_gtk3cairo_internal_check(x):
    try:
        import cairocffi
    except ImportError:
        try:
            import cairo
        except ImportError:
            return (False, "Requires cairocffi or pycairo to be installed.")

    try:
        import gi
    except ImportError:
        return (False, "Requires pygobject to be installed.")

    try:
        gi.require_version("Gtk", "3.0")
    except ValueError:
        return (False, "Requires gtk3 development files to be installed.")
    except AttributeError:
        return (False, "pygobject version too old.")

    try:
        from gi.repository import Gtk, Gdk, GObject
    except (RuntimeError, ImportError):
        return (False, "Requires pygobject to be installed.")

    return (True, "version %s.%s.%s" % (
        Gtk.get_major_version(),
        Gtk.get_micro_version(),
        Gtk.get_minor_version()))


class BackendGtk3Cairo(OptionalBackendPackage):
    name = "gtk3cairo"

    def check_requirements(self):
        if 'TRAVIS' in os.environ:
            raise CheckFailed("Can't build with Travis")

        # This check needs to be performed out-of-process, because
        # importing gi and then importing regular old pygtk afterward
        # segfaults the interpreter.
        try:
            p = multiprocessing.Pool()
        except:
            return "unknown (can not use multiprocessing to determine)"
        try:
            res = p.map_async(backend_gtk3cairo_internal_check, [0])
            success, msg = res.get(timeout=10)[0]
        except multiprocessing.TimeoutError:
            p.terminate()
            # No result returned. Probaly hanging, terminate the process.
            success = False
            raise CheckFailed("Check timed out")
        except:
            p.close()
            success = False
            raise
        else:
            p.close()
        finally:
            p.join()

        if success:
            return msg
        else:
            raise CheckFailed(msg)

    def get_package_data(self):
        return {'matplotlib': ['mpl-data/*.glade']}


class BackendWxAgg(OptionalBackendPackage):
    name = "wxagg"

    def check_requirements(self):
        wxversioninstalled = True
        try:
            import wxversion
        except ImportError:
            wxversioninstalled = False

        if wxversioninstalled:
            try:
                _wx_ensure_failed = wxversion.AlreadyImportedError
            except AttributeError:
                _wx_ensure_failed = wxversion.VersionError

            try:
                wxversion.ensureMinimal('2.8')
            except _wx_ensure_failed:
                pass

        try:
            import wx
            backend_version = wx.VERSION_STRING
        except ImportError:
            raise CheckFailed("requires wxPython")

        # Extra version check in case wxversion lacks AlreadyImportedError;
        # then VersionError might have been raised and ignored when
        # there really *is* a problem with the version.
        major, minor = [int(n) for n in backend_version.split('.')[:2]]
        if major < 2 or (major < 3 and minor < 8):
            raise CheckFailed(
                "Requires wxPython 2.8, found %s" % backend_version)

        return "version %s" % backend_version


class BackendMacOSX(OptionalBackendPackage):
    name = 'macosx'

    def check_requirements(self):
        if sys.platform != 'darwin':
            raise CheckFailed("Mac OS-X only")

        return 'darwin'

    def get_extension(self):
        sources = [
            'src/_macosx.m'
            ]

        ext = make_extension('matplotlib.backends._macosx', sources)
        ext.extra_link_args.extend(['-framework', 'Cocoa'])
        return ext


class Windowing(OptionalBackendPackage):
    """
    Builds the windowing extension.
    """
    name = "windowing"

    def check_requirements(self):
        if sys.platform != 'win32':
            raise CheckFailed("Microsoft Windows only")
        config = self.get_config()
        if config is False:
            raise CheckFailed("skipping due to configuration")
        return ""

    def get_extension(self):
        sources = [
            "src/_windowing.cpp"
            ]
        ext = make_extension('matplotlib._windowing', sources)
        ext.include_dirs.extend(['C:/include'])
        ext.libraries.extend(['user32'])
        ext.library_dirs.extend(['C:/lib'])
        ext.extra_link_args.append("-mwindows")
        return ext


class BackendQtBase(OptionalBackendPackage):

    def convert_qt_version(self, version):
        version = '%x' % version
        temp = []
        while len(version) > 0:
            version, chunk = version[:-2], version[-2:]
            temp.insert(0, str(int(chunk, 16)))
        return '.'.join(temp)

    def check_requirements(self):
        '''
        If PyQt4/PyQt5 is already imported, importing PyQt5/PyQt4 will fail
        so we need to test in a subprocess (as for Gtk3).
        '''
        try:
            p = multiprocessing.Pool()

        except:
            # Can't do multiprocessing, fall back to normal approach ( this will fail if importing both PyQt4 and PyQt5 )
            try:
                # Try in-process
                msg = self.callback(self)

            except RuntimeError:
                raise CheckFailed("Could not import: are PyQt4 & PyQt5 both installed?")

            except:
                # Raise any other exceptions
                raise

        else:
            # Multiprocessing OK
            try:
                res = p.map_async(self.callback, [self])
                msg = res.get(timeout=10)[0]
            except multiprocessing.TimeoutError:
                p.terminate()
                # No result returned. Probaly hanging, terminate the process.
                raise CheckFailed("Check timed out")
            except:
                # Some other error.
                p.close()
                raise
            else:
                # Clean exit
                p.close()
            finally:
                # Tidy up multiprocessing
                p.join()

        return msg


def backend_pyside_internal_check(self):
    try:
        from PySide import __version__
        from PySide import QtCore
    except ImportError:
        raise CheckFailed("PySide not found")
    else:
        return ("Qt: %s, PySide: %s" %
                (QtCore.__version__, __version__))


def backend_pyqt4_internal_check(self):
    try:
        from PyQt4 import QtCore
    except ImportError:
        raise CheckFailed("PyQt4 not found")

    try:
        qt_version = QtCore.QT_VERSION
        pyqt_version_str = QtCore.QT_VERSION_STR
    except AttributeError:
        raise CheckFailed('PyQt4 not correctly imported')
    else:
        return ("Qt: %s, PyQt: %s" % (self.convert_qt_version(qt_version), pyqt_version_str))


def backend_qt4_internal_check(self):
    successes = []
    failures = []
    try:
        successes.append(backend_pyside_internal_check(self))
    except CheckFailed as e:
        failures.append(str(e))

    try:
        successes.append(backend_pyqt4_internal_check(self))
    except CheckFailed as e:
        failures.append(str(e))

    if len(successes) == 0:
        raise CheckFailed('; '.join(failures))
    return '; '.join(successes + failures)


class BackendQt4(BackendQtBase):
    name = "qt4agg"

    def __init__(self, *args, **kwargs):
        BackendQtBase.__init__(self, *args, **kwargs)
        self.callback = backend_qt4_internal_check

def backend_pyside2_internal_check(self):
    try:
        from PySide2 import __version__
        from PySide2 import QtCore
    except ImportError:
        raise CheckFailed("PySide2 not found")
    else:
        return ("Qt: %s, PySide2: %s" %
                (QtCore.__version__, __version__))

def backend_pyqt5_internal_check(self):
    try:
        from PyQt5 import QtCore
    except ImportError:
        raise CheckFailed("PyQt5 not found")

    try:
        qt_version = QtCore.QT_VERSION
        pyqt_version_str = QtCore.QT_VERSION_STR
    except AttributeError:
        raise CheckFailed('PyQt5 not correctly imported')
    else:
        return ("Qt: %s, PyQt: %s" % (self.convert_qt_version(qt_version), pyqt_version_str))

def backend_qt5_internal_check(self):
    successes = []
    failures = []
    try:
        successes.append(backend_pyside2_internal_check(self))
    except CheckFailed as e:
        failures.append(str(e))

    try:
        successes.append(backend_pyqt5_internal_check(self))
    except CheckFailed as e:
        failures.append(str(e))

    if len(successes) == 0:
        raise CheckFailed('; '.join(failures))
    return '; '.join(successes + failures)

class BackendQt5(BackendQtBase):
    name = "qt5agg"

    def __init__(self, *args, **kwargs):
        BackendQtBase.__init__(self, *args, **kwargs)
        self.callback = backend_qt5_internal_check


class BackendCairo(OptionalBackendPackage):
    name = "cairo"

    def check_requirements(self):
        try:
            import cairocffi
        except ImportError:
            try:
                import cairo
            except ImportError:
                raise CheckFailed("cairocffi or pycairo not found")
            else:
                return "pycairo version %s" % cairo.version
        else:
            return "cairocffi version %s" % cairocffi.version


class DviPng(SetupPackage):
    name = "dvipng"
    optional = True

    def check(self):
        try:
            output = check_output('dvipng -version', shell=True,
                                  stderr=subprocess.STDOUT)
            return "version %s" % output.splitlines()[1].decode().split()[-1]
        except (IndexError, ValueError, subprocess.CalledProcessError):
            raise CheckFailed()


class Ghostscript(SetupPackage):
    name = "ghostscript"
    optional = True

    def check(self):
        if sys.platform == 'win32':
            # mgs is the name in miktex
            gs_execs = ['gswin32c', 'gswin64c', 'mgs', 'gs']
        else:
            gs_execs = ['gs']
        for gs_exec in gs_execs:
            try:
                command = gs_exec + ' --version'
                output = check_output(command, shell=True,
                                      stderr=subprocess.STDOUT)
                return "version %s" % output.decode()[:-1]
            except (IndexError, ValueError, subprocess.CalledProcessError):
                pass

        raise CheckFailed()


class LaTeX(SetupPackage):
    name = "latex"
    optional = True

    def check(self):
        try:
            output = check_output('latex -version', shell=True,
                                  stderr=subprocess.STDOUT)
            line = output.splitlines()[0].decode()
            pattern = '(3\.1\d+)|(MiKTeX \d+.\d+)'
            match = re.search(pattern, line)
            return "version %s" % match.group(0)
        except (IndexError, ValueError, AttributeError, subprocess.CalledProcessError):
            raise CheckFailed()


class PdfToPs(SetupPackage):
    name = "pdftops"
    optional = True

    def check(self):
        try:
            output = check_output('pdftops -v', shell=True,
                                  stderr=subprocess.STDOUT)
            for line in output.splitlines():
                line = line.decode()
                if 'version' in line:
                    return "version %s" % line.split()[2]
        except (IndexError, ValueError, subprocess.CalledProcessError):
            pass

        raise CheckFailed()


class OptionalPackageData(OptionalPackage):
    config_category = "package_data"


class Dlls(OptionalPackageData):
    """
    On Windows, this packages any DLL files that can be found in the
    lib/matplotlib/* directories.
    """
    name = "dlls"

    def check_requirements(self):
        if sys.platform != 'win32':
            raise CheckFailed("Microsoft Windows only")

    def get_package_data(self):
        return {'': ['*.dll']}

    @classmethod
    def get_config(cls):
        """
        Look at `setup.cfg` and return one of ["auto", True, False] indicating
        if the package is at default state ("auto"), forced by the user (True)
        or opted-out (False).
        """
        try:
            return config.getboolean(cls.config_category, cls.name)
        except:
            return False  # <-- default