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  $   ˆl–Ãa¾”JeJ‚ÆÅq·Å£Â„YyŸÁÀ¿ ,w    # -*- coding: utf-8 -*-
# Copyright (C) 2015 mulhern <amulhern@redhat.com>

# This library is free software; you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by the
# Free Software Foundation; either version 2.1 of the License, or (at your
# option) any later version.

# This library is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
# for more details.

# You should have received a copy of the GNU Lesser General Public License
# along with this library; if not, write to the Free Software Foundation,
# Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
"""
    pyudev.discover
    ===============

    Tools to discover a device given limited information.

    .. moduleauthor::  mulhern <amulhern@redhat.com>
"""

from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
from __future__ import unicode_literals

import abc
import functools
import os
import re
import six

from pyudev._errors import DeviceNotFoundError

from pyudev.device import Devices


def wrap_exception(func):
    """
    Allow Device discovery methods to return None instead of raising an
    exception.
    """

    @functools.wraps(func)
    def the_func(*args, **kwargs):
        """
        Returns result of calling ``func`` on ``args``, ``kwargs``.
        Returns None if ``func`` raises :exc:`DeviceNotFoundError`.
        """
        try:
            return func(*args, **kwargs)
        except DeviceNotFoundError:
            return None

    return the_func


@six.add_metaclass(abc.ABCMeta)
class Hypothesis(object):
    """
    Represents a hypothesis about the meaning of the device identifier.
    """

    @classmethod
    @abc.abstractmethod
    def match(cls, value):  # pragma: no cover
        """
        Match the given string according to the hypothesis.

        The purpose of this method is to obtain a value corresponding to
        ``value`` if that is possible. It may use a regular expression, but
        in general it should just return ``value`` and let the lookup method
        sort out the rest.

        :param str value: the string to inspect
        :returns: the matched thing or None if unmatched
        :rtype: the type of lookup's key parameter or NoneType
        """
        raise NotImplementedError()

    @classmethod
    @abc.abstractmethod
    def lookup(cls, context, key):  # pragma: no cover
        """
        Lookup the given string according to the hypothesis.

        :param Context context: the pyudev context
        :param key: a key with which to lookup the device
        :type key: the type of match's return value if not None
        :returns: a list of Devices obtained
        :rtype: frozenset of :class:`Device`
        """
        raise NotImplementedError()

    @classmethod
    def setup(cls, context):
        """
        A potentially expensive method that may allow an :class:`Hypothesis`
        to find devices more rapidly or to find a device that it would
        otherwise miss.

        :param Context context: the pyudev context
        """
        pass

    @classmethod
    def get_devices(cls, context, value):
        """
        Get any devices that may correspond to the given string.

        :param Context context: the pyudev context
        :param str value: the value to look for
        :returns: a list of devices obtained
        :rtype: set of :class:`Device`
        """
        key = cls.match(value)
        return cls.lookup(context, key) if key is not None else frozenset()


class DeviceNumberHypothesis(Hypothesis):
    """
    Represents the hypothesis that the device is a device number.

    The device may be separated into major/minor number or a composite number.
    """

    @classmethod
    def _match_major_minor(cls, value):
        """
        Match t