105 lines
3.0 KiB
Python
105 lines
3.0 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2014-2016 OpenMarket Ltd
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from twisted.internet import defer, reactor
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from .logcontext import preserve_context_over_deferred
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def sleep(seconds):
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d = defer.Deferred()
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reactor.callLater(seconds, d.callback, seconds)
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return preserve_context_over_deferred(d)
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def run_on_reactor():
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""" This will cause the rest of the function to be invoked upon the next
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iteration of the main loop
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"""
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return sleep(0)
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class ObservableDeferred(object):
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"""Wraps a deferred object so that we can add observer deferreds. These
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observer deferreds do not affect the callback chain of the original
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deferred.
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If consumeErrors is true errors will be captured from the origin deferred.
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Cancelling or otherwise resolving an observer will not affect the original
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ObservableDeferred.
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"""
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__slots__ = ["_deferred", "_observers", "_result"]
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def __init__(self, deferred, consumeErrors=False):
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object.__setattr__(self, "_deferred", deferred)
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object.__setattr__(self, "_result", None)
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object.__setattr__(self, "_observers", set())
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def callback(r):
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object.__setattr__(self, "_result", (True, r))
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while self._observers:
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try:
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self._observers.pop().callback(r)
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except:
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pass
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return r
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def errback(f):
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object.__setattr__(self, "_result", (False, f))
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while self._observers:
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try:
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self._observers.pop().errback(f)
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except:
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pass
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if consumeErrors:
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return None
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else:
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return f
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deferred.addCallbacks(callback, errback)
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def observe(self):
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if not self._result:
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d = defer.Deferred()
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def remove(r):
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self._observers.discard(d)
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return r
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d.addBoth(remove)
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self._observers.add(d)
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return d
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else:
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success, res = self._result
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return defer.succeed(res) if success else defer.fail(res)
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def observers(self):
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return self._observers
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def __getattr__(self, name):
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return getattr(self._deferred, name)
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def __setattr__(self, name, value):
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setattr(self._deferred, name, value)
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def __repr__(self):
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return "<ObservableDeferred object at %s, result=%r, _deferred=%r>" % (
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id(self), self._result, self._deferred,
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)
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