105 lines
3.0 KiB
Python
105 lines
3.0 KiB
Python
# -*- coding: utf-8 -*-
|
|
# Copyright 2014, 2015 OpenMarket Ltd
|
|
#
|
|
# Licensed under the Apache License, Version 2.0 (the "License");
|
|
# you may not use this file except in compliance with the License.
|
|
# You may obtain a copy of the License at
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
# distributed under the License is distributed on an "AS IS" BASIS,
|
|
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
# See the License for the specific language governing permissions and
|
|
# limitations under the License.
|
|
|
|
|
|
from twisted.internet import defer, reactor
|
|
|
|
from .logcontext import preserve_context_over_deferred
|
|
|
|
|
|
def sleep(seconds):
|
|
d = defer.Deferred()
|
|
reactor.callLater(seconds, d.callback, seconds)
|
|
return preserve_context_over_deferred(d)
|
|
|
|
|
|
def run_on_reactor():
|
|
""" This will cause the rest of the function to be invoked upon the next
|
|
iteration of the main loop
|
|
"""
|
|
return sleep(0)
|
|
|
|
|
|
class ObservableDeferred(object):
|
|
"""Wraps a deferred object so that we can add observer deferreds. These
|
|
observer deferreds do not affect the callback chain of the original
|
|
deferred.
|
|
|
|
If consumeErrors is true errors will be captured from the origin deferred.
|
|
|
|
Cancelling or otherwise resolving an observer will not affect the original
|
|
ObservableDeferred.
|
|
"""
|
|
|
|
__slots__ = ["_deferred", "_observers", "_result"]
|
|
|
|
def __init__(self, deferred, consumeErrors=False):
|
|
object.__setattr__(self, "_deferred", deferred)
|
|
object.__setattr__(self, "_result", None)
|
|
object.__setattr__(self, "_observers", set())
|
|
|
|
def callback(r):
|
|
object.__setattr__(self, "_result", (True, r))
|
|
while self._observers:
|
|
try:
|
|
self._observers.pop().callback(r)
|
|
except:
|
|
pass
|
|
return r
|
|
|
|
def errback(f):
|
|
object.__setattr__(self, "_result", (False, f))
|
|
while self._observers:
|
|
try:
|
|
self._observers.pop().errback(f)
|
|
except:
|
|
pass
|
|
|
|
if consumeErrors:
|
|
return None
|
|
else:
|
|
return f
|
|
|
|
deferred.addCallbacks(callback, errback)
|
|
|
|
def observe(self):
|
|
if not self._result:
|
|
d = defer.Deferred()
|
|
|
|
def remove(r):
|
|
self._observers.discard(d)
|
|
return r
|
|
d.addBoth(remove)
|
|
|
|
self._observers.add(d)
|
|
return d
|
|
else:
|
|
success, res = self._result
|
|
return defer.succeed(res) if success else defer.fail(res)
|
|
|
|
def observers(self):
|
|
return self._observers
|
|
|
|
def __getattr__(self, name):
|
|
return getattr(self._deferred, name)
|
|
|
|
def __setattr__(self, name, value):
|
|
setattr(self._deferred, name, value)
|
|
|
|
def __repr__(self):
|
|
return "<ObservableDeferred object at %s, result=%r, _deferred=%r>" % (
|
|
id(self), self._result, self._deferred,
|
|
)
|