Mini Shell

# Copyright 2016, Tresys Technology, LLC
# Copyright 2018, Chris PeBenito <pebenito@ieee.org>
#
# This file is part of SETools.
#
# SETools 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.
#
# SETools 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 SETools.  If not, see
# <http://www.gnu.org/licenses/>.
#
from ..exception import MLSDisabled

from .difference import SymbolWrapper, Wrapper
from .mls import RangeWrapper
from .roles import role_wrapper_factory
from .types import type_wrapper_factory
from .users import user_wrapper_factory


class ContextWrapper(Wrapper):

    """Wrap contexts to allow comparisons."""

    __slots__ = ("user", "role", "type_", "range_")

    def __init__(self, ctx):
        self.origin = ctx
        self.user = user_wrapper_factory(ctx.user)
        self.role = role_wrapper_factory(ctx.role)
        self.type_ = type_wrapper_factory(ctx.type_)

        try:
            self.range_ = RangeWrapper(ctx.range_)
        except MLSDisabled:
            self.range_ = None

    def __hash__(self):
        return hash(self.origin)

    def __eq__(self, other):
        return self.user == other.user and \
            self.role == other.role and \
            self.type_ == other.type_ and \
            self.range_ == other.range_

    def __lt__(self, other):
        return self.user < other.user and \
            self.role < other.role and \
            self.type_ < other.type_ and \
            self.range_ < other.range_