# Copyright (c) 2013 Paul Tagliamonte <paultag@debian.org>
# Copyright (c) 2013 Julien Danjou <julien@danjou.info>
#
# Permission is hereby granted, free of charge, to any person obtaining a
# copy of this software and associated documentation files (the "Software"),
# to deal in the Software without restriction, including without limitation
# the rights to use, copy, modify, merge, publish, distribute, sublicense,
# and/or sell copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
# THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
# DEALINGS IN THE SOFTWARE.

import contextlib
import sys


if sys.version_info[0] >= 3:
    str_type = str
else:
    str_type = unicode


@contextlib.contextmanager
def temporary_attribute_value(obj, attribute, value):
    """Temporarily switch an object attribute value to another value."""
    original_value = getattr(obj, attribute)
    setattr(obj, attribute, value)

    try:
        yield
    except Exception:
        pass

    setattr(obj, attribute, original_value)


def flatten_literal_list(entry):
    for e in entry:
        if type(e) == list:
            for x in flatten_literal_list(e):
                yield x  # needs more yield-from
        else:
            yield e