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- # -*- coding: utf-8 -*-
- # Copyright 2014-2016 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.
- import logging
- from itertools import islice
- import attr
- from twisted.internet import defer, task
- from synapse.util.logcontext import PreserveLoggingContext
- logger = logging.getLogger(__name__)
- def unwrapFirstError(failure):
- # defer.gatherResults and DeferredLists wrap failures.
- failure.trap(defer.FirstError)
- return failure.value.subFailure
- @attr.s
- class Clock(object):
- """
- A Clock wraps a Twisted reactor and provides utilities on top of it.
- Args:
- reactor: The Twisted reactor to use.
- """
- _reactor = attr.ib()
- @defer.inlineCallbacks
- def sleep(self, seconds):
- d = defer.Deferred()
- with PreserveLoggingContext():
- self._reactor.callLater(seconds, d.callback, seconds)
- res = yield d
- defer.returnValue(res)
- def time(self):
- """Returns the current system time in seconds since epoch."""
- return self._reactor.seconds()
- def time_msec(self):
- """Returns the current system time in miliseconds since epoch."""
- return int(self.time() * 1000)
- def looping_call(self, f, msec):
- """Call a function repeatedly.
- Waits `msec` initially before calling `f` for the first time.
- Args:
- f(function): The function to call repeatedly.
- msec(float): How long to wait between calls in milliseconds.
- """
- call = task.LoopingCall(f)
- call.clock = self._reactor
- call.start(msec / 1000.0, now=False)
- return call
- def call_later(self, delay, callback, *args, **kwargs):
- """Call something later
- Args:
- delay(float): How long to wait in seconds.
- callback(function): Function to call
- *args: Postional arguments to pass to function.
- **kwargs: Key arguments to pass to function.
- """
- def wrapped_callback(*args, **kwargs):
- with PreserveLoggingContext():
- callback(*args, **kwargs)
- with PreserveLoggingContext():
- return self._reactor.callLater(delay, wrapped_callback, *args, **kwargs)
- def cancel_call_later(self, timer, ignore_errs=False):
- try:
- timer.cancel()
- except Exception:
- if not ignore_errs:
- raise
- def batch_iter(iterable, size):
- """batch an iterable up into tuples with a maximum size
- Args:
- iterable (iterable): the iterable to slice
- size (int): the maximum batch size
- Returns:
- an iterator over the chunks
- """
- # make sure we can deal with iterables like lists too
- sourceiter = iter(iterable)
- # call islice until it returns an empty tuple
- return iter(lambda: tuple(islice(sourceiter, size)), ())
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