# Source code for aioxmpp.sasl

    ########################################################################
    # File name: sasl.py
    # This file is part of: aioxmpp
    #
    # LICENSE
    #
    # This program 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 3 of the
    # License, or (at your option) any later version.
    #
    # This program 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 program.  If not, see
    # <http://www.gnu.org/licenses/>.
    #
    ########################################################################
    """
    :mod:`~aioxmpp.sasl` -- SASL helpers
    ####################################

    This module is used to implement SASL in :mod:`aioxmpp.security_layer`. It
    provides a state machine for use by the different SASL mechanisms and
    implementations of some SASL mechanisms.

    It provides an XMPP adaptor for :mod:`aiosasl`.

    .. autoclass:: SASLXMPPInterface

    The XSOs for SASL authentication can be found in :mod:`aioxmpp.nonza`.

    """

    import asyncio
    import logging

    import aiosasl

    from . import protocol, nonza

    logger = logging.getLogger(__name__)

    class SASLXMPPInterface(aiosasl.SASLInterface):
        def __init__(self, xmlstream):
            super().__init__()
            self.xmlstream = xmlstream
            self.timeout = None

        async def _send_sasl_node_and_wait_for(self, node):
            node = await protocol.send_and_wait_for(
                self.xmlstream,
                [node],
                [
                    nonza.SASLChallenge,
                    nonza.SASLFailure,
                    nonza.SASLSuccess
                ],
                timeout=self.timeout
            )

            state = node.TAG[1]

            if state == "failure":
                xmpp_error = node.condition[1]
                text = node.text
                raise aiosasl.SASLFailure(xmpp_error, text=text)

            if hasattr(node, "payload"):
                payload = node.payload
            else:
                payload = None

            return state, payload

        async def initiate(self, mechanism, payload=None):
            with self.xmlstream.mute():
                return await self._send_sasl_node_and_wait_for(
                    nonza.SASLAuth(mechanism=mechanism,
                                   payload=payload))

        async def respond(self, payload):
            with self.xmlstream.mute():
                return await self._send_sasl_node_and_wait_for(
                    nonza.SASLResponse(payload=payload)
                )

        async def abort(self):
            try:
                next_state, payload = await self._send_sasl_node_and_wait_for(
                    nonza.SASLAbort()
                )
            except aiosasl.SASLFailure as err:
                self._state = "failure"
                if err.opaque_error != "aborted":
                    raise
                return "failure", None
            else:
                raise aiosasl.SASLFailure(
                    "aborted",
                    text="unexpected non-failure after abort: "
                    "{}".format(self._state)
                )