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# Copyright (C) 2020 Philipp Hörist <philipp AT hoerist.com>
#
# This file is part of nbxmpp.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; If not, see <http://www.gnu.org/licenses/>.
import weakref
import inspect
import logging
from enum import IntEnum
from functools import wraps
from gi.repository import Soup
from nbxmpp.errors import is_error
from nbxmpp.errors import CancelledError
from nbxmpp.errors import TimeoutStanzaError
from nbxmpp.simplexml import Node
from nbxmpp.modules.util import make_func_arguments_string
log = logging.getLogger('nbxmpp.task')
class _ResultSet:
pass
ResultSet = _ResultSet()
class NoType:
pass
class TaskState(IntEnum):
INIT = 0
RUNNING = 1
FINISHED = 2
CANCELLED = 3
@property
def is_init(self):
return self == TaskState.INIT
@property
def is_running(self):
return self == TaskState.RUNNING
@property
def is_finished(self):
return self == TaskState.FINISHED
@property
def is_cancelled(self):
return self == TaskState.CANCELLED
def _setup_task(task, client, callback, user_data):
client.add_task(task)
task.set_finalize_func(client.remove_task)
task.set_user_data(user_data)
if callback is not None:
task.add_done_callback(callback)
task.start()
return task
def iq_request_task(func):
@wraps(func)
def func_wrapper(self, *args, timeout=None, callback=None, user_data=None, **kwargs):
if self._log.isEnabledFor(logging.INFO):
self._log.info(make_func_arguments_string(func, self, args, kwargs))
task = IqRequestTask(func(self, *args, **kwargs),
self._log,
self._client)
task.set_timeout(timeout)
return _setup_task(task, self._client, callback, user_data)
return func_wrapper
def http_request_task(func):
@wraps(func)
def func_wrapper(self, *args, callback=None, user_data=None, **kwargs):
task = HTTPRequestTask(func(self, *args, **kwargs),
self._log,
self._soup_session)
return _setup_task(task, self._client, callback, user_data)
return func_wrapper
def is_fatal_error(error):
if is_error(error):
return error.is_fatal
return isinstance(error, Exception)
class Task:
'''
Base class for wrapping a generator method.
It runs the generator depending on what the generator yields. If the
generator yields another generator a sub task is created. If it yields
a type defined in _process_types, _run_async() is called which needs to
be implemented by classes.
the implementation of _run_async() must be really async, means it should
not call _async_finished() in the same mainloop cycle. Otherwise sub tasks
may break. _async_finished() needs to call _next_step(result).
'''
_process_types = (NoType,)
def __init__(self, gen, logger=log):
self._logger = logger
self._gen = gen
self._done_callbacks = []
self._sub_task = None
self._result = None
self._error = None
self._user_data = None
self._timeout = None
self._finalize_func = None
self._finalize_context = None
self._state = TaskState.INIT
@property
def state(self):
return self._state
def add_done_callback(self, callback, weak=True):
if self._state.is_finished or self._state.is_cancelled:
raise RuntimeError('Task is finished')
if weak:
if inspect.ismethod(callback):
callback = weakref.WeakMethod(callback)
elif inspect.isfunction(callback):
callback = weakref.ref(callback)
else:
ValueError('Unknown callback object')
self._done_callbacks.append(callback)
def set_timeout(self, timeout):
self._timeout = timeout
def start(self):
if not self._state.is_init:
raise RuntimeError('Task already started')
self._state = TaskState.RUNNING
next(self._gen)
self._next_step(self)
def _run_async(self, data):
raise NotImplementedError
def _async_finished(self, *args, **kwargs):
raise NotImplementedError
def _sub_task_completed(self, task):
self._sub_task = None
if not self._state.is_running:
return
result = task.get_result()
if is_fatal_error(result):
self._error = result
self._set_finished()
else:
self._next_step(result)
def _next_step(self, result):
try:
res = self._gen.send(result)
except StopIteration:
self._set_finished()
return
except Exception as error:
self._log_if_fatal(error)
self._error = error
self._set_finished()
return
if isinstance(res, self._process_types):
self._run_async(res)
elif isinstance(res, Task):
if self._sub_task is not None:
RuntimeError('Only one sub task can be active')
self._sub_task = res
self._sub_task.add_done_callback(self._sub_task_completed,
weak=False)
else:
if res is not ResultSet:
self._result = res
self._set_finished()
def _set_finished(self):
self._state = TaskState.FINISHED
self._invoke_callbacks()
self._finalize()
def _log_if_fatal(self, error):
if is_error(error):
if error.is_fatal:
self._logger.log(error.log_level, error)
elif isinstance(error, Exception):
self._logger.exception('Fatal Exception')
def _invoke_callbacks(self):
for callback in self._done_callbacks:
if isinstance(callback, weakref.WeakMethod):
callback = callback()
if callback is None:
return
# Be conservative with catching exceptions here
# For example unittests raise Assertion errors
# which should not be catched here
try:
callback(self)
except CancelledError:
pass
def set_result(self, result):
self._result = result
return ResultSet
def get_result(self):
# if self._error is None, there was no error
# but None is a valid value for self._result
if self._error is not None:
return self._error
return self._result
def finish(self):
if self._error is not None:
raise self._error # pylint: disable=raising-bad-type
return self._result
def set_user_data(self, user_data):
self._user_data = user_data
def get_user_data(self):
return self._user_data
def set_finalize_func(self, func, context=None):
self._finalize_func = func
self._finalize_context = context
def cancel(self):
if not self._state.is_running:
return
self._state = TaskState.CANCELLED
if self._sub_task is not None:
self._sub_task.cancel()
self._error = CancelledError()
self._invoke_callbacks()
self._finalize()
def _finalize(self):
self._done_callbacks.clear()
self._sub_task = None
self._error = None
self._result = None
self._user_data = None
self._gen.close()
if self._finalize_func is not None:
self._finalize_func(self, self._finalize_context)
class IqRequestTask(Task):
'''
A Task for running IQ requests
'''
_process_types = (Node,)
def __init__(self, gen, logger, client):
super().__init__(gen, logger)
self._client = client
self._iq_id = None
def _run_async(self, stanza):
self._iq_id = self._client.send_stanza(stanza,
callback=self._async_finished,
timeout=self._timeout)
def _async_finished(self, _client, result, *args, **kwargs):
if self._state == TaskState.CANCELLED:
return
if result is None:
self._error = TimeoutStanzaError()
self._set_finished()
return
self._next_step(result)
def _finalize(self):
if self._iq_id is not None:
self._client._dispatcher.remove_iq_callback(self._iq_id)
self._client = None
super()._finalize()
class HTTPRequestTask(Task):
'''
A Task for running HTTP requests
'''
_process_types = (Soup.Message,)
def __init__(self, gen, logger, session):
super().__init__(gen, logger)
self._session = session
def _run_async(self, message):
self._session.queue_message(message, self._async_finished, None)
def _async_finished(self, _session, message, _user_data):
if self._state != TaskState.CANCELLED:
self._next_step(message)
def _finalize(self):
self._session = None
super()._finalize()
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