127 lines
3.9 KiB
Python
127 lines
3.9 KiB
Python
# Copyright (c) Twisted Matrix Laboratories.
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# See LICENSE for details.
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"""
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Extended thread dispatching support.
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For basic support see reactor threading API docs.
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"""
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from __future__ import division, absolute_import
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from twisted.python.compat import _PY3
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if not _PY3:
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import Queue
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else:
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import queue as Queue
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from twisted.python import failure
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from twisted.internet import defer
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def deferToThreadPool(reactor, threadpool, f, *args, **kwargs):
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"""
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Call the function C{f} using a thread from the given threadpool and return
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the result as a Deferred.
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This function is only used by client code which is maintaining its own
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threadpool. To run a function in the reactor's threadpool, use
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C{deferToThread}.
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@param reactor: The reactor in whose main thread the Deferred will be
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invoked.
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@param threadpool: An object which supports the C{callInThreadWithCallback}
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method of C{twisted.python.threadpool.ThreadPool}.
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@param f: The function to call.
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@param *args: positional arguments to pass to f.
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@param **kwargs: keyword arguments to pass to f.
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@return: A Deferred which fires a callback with the result of f, or an
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errback with a L{twisted.python.failure.Failure} if f throws an
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exception.
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"""
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d = defer.Deferred()
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def onResult(success, result):
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if success:
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reactor.callFromThread(d.callback, result)
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else:
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reactor.callFromThread(d.errback, result)
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threadpool.callInThreadWithCallback(onResult, f, *args, **kwargs)
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return d
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def deferToThread(f, *args, **kwargs):
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"""
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Run a function in a thread and return the result as a Deferred.
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@param f: The function to call.
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@param *args: positional arguments to pass to f.
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@param **kwargs: keyword arguments to pass to f.
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@return: A Deferred which fires a callback with the result of f,
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or an errback with a L{twisted.python.failure.Failure} if f throws
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an exception.
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"""
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from twisted.internet import reactor
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return deferToThreadPool(reactor, reactor.getThreadPool(),
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f, *args, **kwargs)
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def _runMultiple(tupleList):
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"""
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Run a list of functions.
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"""
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for f, args, kwargs in tupleList:
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f(*args, **kwargs)
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def callMultipleInThread(tupleList):
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"""
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Run a list of functions in the same thread.
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tupleList should be a list of (function, argsList, kwargsDict) tuples.
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"""
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from twisted.internet import reactor
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reactor.callInThread(_runMultiple, tupleList)
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def blockingCallFromThread(reactor, f, *a, **kw):
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"""
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Run a function in the reactor from a thread, and wait for the result
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synchronously. If the function returns a L{Deferred}, wait for its
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result and return that.
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@param reactor: The L{IReactorThreads} provider which will be used to
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schedule the function call.
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@param f: the callable to run in the reactor thread
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@type f: any callable.
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@param a: the arguments to pass to C{f}.
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@param kw: the keyword arguments to pass to C{f}.
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@return: the result of the L{Deferred} returned by C{f}, or the result
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of C{f} if it returns anything other than a L{Deferred}.
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@raise: If C{f} raises a synchronous exception,
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C{blockingCallFromThread} will raise that exception. If C{f}
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returns a L{Deferred} which fires with a L{Failure},
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C{blockingCallFromThread} will raise that failure's exception (see
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L{Failure.raiseException}).
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"""
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queue = Queue.Queue()
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def _callFromThread():
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result = defer.maybeDeferred(f, *a, **kw)
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result.addBoth(queue.put)
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reactor.callFromThread(_callFromThread)
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result = queue.get()
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if isinstance(result, failure.Failure):
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result.raiseException()
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return result
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__all__ = ["deferToThread", "deferToThreadPool", "callMultipleInThread",
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"blockingCallFromThread"]
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