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Viewing changes to vendor/Twisted-10.0.0/twisted/python/threadable.py

  • Committer: Jesse Andrews
  • Date: 2010-05-28 06:05:26 UTC
  • Revision ID: git-v1:bf6e6e718cdc7488e2da87b21e258ccc065fe499
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vendor/Twisted-10.0.0/twisted/python/threadable.py
 
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# -*- test-case-name: twisted.python.threadable -*-
 
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# Copyright (c) 2001-2004 Twisted Matrix Laboratories.
 
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# See LICENSE for details.
 
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"""
 
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A module that will allow your program to be multi-threaded,
 
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micro-threaded, and single-threaded.  Currently microthreads are
 
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unimplemented.  The idea is to abstract away some commonly used
 
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functionality so that I don't have to special-case it in all programs.
 
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"""
 
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import warnings
 
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from twisted.python import hook
 
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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, *a, **b):
 
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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, *a, **b):
 
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    self._threadable_lock.release()
 
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def synchronize(*klasses):
 
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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 threadmodule is not None:
 
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        for klass in klasses:
 
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            for methodName in klass.synchronized:
 
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                hook.addPre(klass, methodName, _synchPre)
 
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                hook.addPost(klass, methodName, _synchPost)
 
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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 threadmodule 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 threadmodule is None:
 
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        return _dummyID
 
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    return threadmodule.get_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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def whenThreaded(cb):
 
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    warnings.warn("threadable.whenThreaded is deprecated. "
 
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                  "Use application-level logic instead.",
 
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                  DeprecationWarning, stacklevel=2)
 
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    cb()
 
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try:
 
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    import thread as threadmodule
 
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    import threading as threadingmodule
 
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except ImportError:
 
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    threadmodule = None
 
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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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           'whenThreaded']