140 lines
3.1 KiB
Python
140 lines
3.1 KiB
Python
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# -*- test-case-name: twisted.python.test_threadable -*-
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# Copyright (c) Twisted Matrix Laboratories.
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# See LICENSE for details.
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"""
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A module to provide some very basic threading primitives, such as
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synchronization.
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"""
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from __future__ import division, absolute_import
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from functools import wraps
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class DummyLock(object):
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"""
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Hack to allow locks to be unpickled on an unthreaded system.
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"""
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def __reduce__(self):
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return (unpickle_lock, ())
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def unpickle_lock():
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if threadingmodule is not None:
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return XLock()
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else:
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return DummyLock()
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unpickle_lock.__safe_for_unpickling__ = True
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def _synchPre(self):
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if '_threadable_lock' not in self.__dict__:
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_synchLockCreator.acquire()
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if '_threadable_lock' not in self.__dict__:
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self.__dict__['_threadable_lock'] = XLock()
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_synchLockCreator.release()
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self._threadable_lock.acquire()
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def _synchPost(self):
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self._threadable_lock.release()
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def _sync(klass, function):
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@wraps(function)
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def sync(self, *args, **kwargs):
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_synchPre(self)
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try:
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return function(self, *args, **kwargs)
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finally:
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_synchPost(self)
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return sync
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def synchronize(*klasses):
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"""
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Make all methods listed in each class' synchronized attribute synchronized.
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The synchronized attribute should be a list of strings, consisting of the
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names of methods that must be synchronized. If we are running in threaded
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mode these methods will be wrapped with a lock.
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"""
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if threadingmodule is not None:
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for klass in klasses:
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for methodName in klass.synchronized:
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sync = _sync(klass, klass.__dict__[methodName])
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setattr(klass, methodName, sync)
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def init(with_threads=1):
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"""Initialize threading.
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Don't bother calling this. If it needs to happen, it will happen.
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"""
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global threaded, _synchLockCreator, XLock
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if with_threads:
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if not threaded:
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if threadingmodule is not None:
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threaded = True
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class XLock(threadingmodule._RLock, object):
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def __reduce__(self):
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return (unpickle_lock, ())
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_synchLockCreator = XLock()
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else:
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raise RuntimeError("Cannot initialize threading, platform lacks thread support")
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else:
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if threaded:
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raise RuntimeError("Cannot uninitialize threads")
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else:
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pass
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_dummyID = object()
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def getThreadID():
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if threadingmodule is None:
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return _dummyID
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return threadingmodule.currentThread().ident
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def isInIOThread():
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"""Are we in the thread responsable for I/O requests (the event loop)?
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"""
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return ioThread == getThreadID()
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def registerAsIOThread():
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"""Mark the current thread as responsable for I/O requests.
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"""
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global ioThread
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ioThread = getThreadID()
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ioThread = None
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threaded = False
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try:
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import threading as threadingmodule
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except ImportError:
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threadingmodule = None
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else:
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init(True)
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__all__ = ['isInIOThread', 'registerAsIOThread', 'getThreadID', 'XLock']
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