1331 lines
46 KiB
Python
1331 lines
46 KiB
Python
"""Thread module emulating a subset of Java's threading model."""
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import sys as _sys
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try:
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import thread
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except ImportError:
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del _sys.modules[__name__]
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raise
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import warnings
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from collections import deque as _deque
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from itertools import count as _count
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from time import time as _time, sleep as _sleep
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from traceback import format_exc as _format_exc
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# Note regarding PEP 8 compliant aliases
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# This threading model was originally inspired by Java, and inherited
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# the convention of camelCase function and method names from that
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# language. While those names are not in any imminent danger of being
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# deprecated, starting with Python 2.6, the module now provides a
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# PEP 8 compliant alias for any such method name.
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# Using the new PEP 8 compliant names also facilitates substitution
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# with the multiprocessing module, which doesn't provide the old
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# Java inspired names.
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# Rename some stuff so "from threading import *" is safe
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__all__ = ['activeCount', 'active_count', 'Condition', 'currentThread',
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'current_thread', 'enumerate', 'Event',
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'Lock', 'RLock', 'Semaphore', 'BoundedSemaphore', 'Thread',
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'Timer', 'setprofile', 'settrace', 'local', 'stack_size']
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_start_new_thread = thread.start_new_thread
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_allocate_lock = thread.allocate_lock
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_get_ident = thread.get_ident
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ThreadError = thread.error
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del thread
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# sys.exc_clear is used to work around the fact that except blocks
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# don't fully clear the exception until 3.0.
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warnings.filterwarnings('ignore', category=DeprecationWarning,
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module='threading', message='sys.exc_clear')
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# Debug support (adapted from ihooks.py).
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# All the major classes here derive from _Verbose. We force that to
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# be a new-style class so that all the major classes here are new-style.
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# This helps debugging (type(instance) is more revealing for instances
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# of new-style classes).
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_VERBOSE = False
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if __debug__:
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class _Verbose(object):
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def __init__(self, verbose=None):
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if verbose is None:
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verbose = _VERBOSE
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self.__verbose = verbose
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def _note(self, format, *args):
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if self.__verbose:
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format = format % args
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# Issue #4188: calling current_thread() can incur an infinite
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# recursion if it has to create a DummyThread on the fly.
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ident = _get_ident()
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try:
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name = _active[ident].name
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except KeyError:
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name = "<OS thread %d>" % ident
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format = "%s: %s\n" % (name, format)
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_sys.stderr.write(format)
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else:
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# Disable this when using "python -O"
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class _Verbose(object):
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def __init__(self, verbose=None):
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pass
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def _note(self, *args):
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pass
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# Support for profile and trace hooks
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_profile_hook = None
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_trace_hook = None
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def setprofile(func):
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"""Set a profile function for all threads started from the threading module.
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The func will be passed to sys.setprofile() for each thread, before its
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run() method is called.
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"""
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global _profile_hook
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_profile_hook = func
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def settrace(func):
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"""Set a trace function for all threads started from the threading module.
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The func will be passed to sys.settrace() for each thread, before its run()
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method is called.
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"""
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global _trace_hook
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_trace_hook = func
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# Synchronization classes
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Lock = _allocate_lock
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def RLock(*args, **kwargs):
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"""Factory function that returns a new reentrant lock.
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A reentrant lock must be released by the thread that acquired it. Once a
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thread has acquired a reentrant lock, the same thread may acquire it again
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without blocking; the thread must release it once for each time it has
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acquired it.
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"""
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return _RLock(*args, **kwargs)
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class _RLock(_Verbose):
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"""A reentrant lock must be released by the thread that acquired it. Once a
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thread has acquired a reentrant lock, the same thread may acquire it
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again without blocking; the thread must release it once for each time it
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has acquired it.
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"""
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def __init__(self, verbose=None):
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_Verbose.__init__(self, verbose)
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self.__block = _allocate_lock()
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self.__owner = None
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self.__count = 0
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def __repr__(self):
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owner = self.__owner
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try:
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owner = _active[owner].name
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except KeyError:
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pass
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return "<%s owner=%r count=%d>" % (
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self.__class__.__name__, owner, self.__count)
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def acquire(self, blocking=1):
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"""Acquire a lock, blocking or non-blocking.
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When invoked without arguments: if this thread already owns the lock,
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increment the recursion level by one, and return immediately. Otherwise,
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if another thread owns the lock, block until the lock is unlocked. Once
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the lock is unlocked (not owned by any thread), then grab ownership, set
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the recursion level to one, and return. If more than one thread is
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blocked waiting until the lock is unlocked, only one at a time will be
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able to grab ownership of the lock. There is no return value in this
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case.
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When invoked with the blocking argument set to true, do the same thing
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as when called without arguments, and return true.
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When invoked with the blocking argument set to false, do not block. If a
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call without an argument would block, return false immediately;
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otherwise, do the same thing as when called without arguments, and
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return true.
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"""
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me = _get_ident()
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if self.__owner == me:
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self.__count = self.__count + 1
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if __debug__:
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self._note("%s.acquire(%s): recursive success", self, blocking)
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return 1
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rc = self.__block.acquire(blocking)
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if rc:
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self.__owner = me
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self.__count = 1
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if __debug__:
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self._note("%s.acquire(%s): initial success", self, blocking)
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else:
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if __debug__:
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self._note("%s.acquire(%s): failure", self, blocking)
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return rc
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__enter__ = acquire
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def release(self):
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"""Release a lock, decrementing the recursion level.
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If after the decrement it is zero, reset the lock to unlocked (not owned
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by any thread), and if any other threads are blocked waiting for the
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lock to become unlocked, allow exactly one of them to proceed. If after
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the decrement the recursion level is still nonzero, the lock remains
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locked and owned by the calling thread.
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Only call this method when the calling thread owns the lock. A
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RuntimeError is raised if this method is called when the lock is
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unlocked.
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There is no return value.
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"""
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if self.__owner != _get_ident():
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raise RuntimeError("cannot release un-acquired lock")
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self.__count = count = self.__count - 1
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if not count:
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self.__owner = None
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self.__block.release()
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if __debug__:
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self._note("%s.release(): final release", self)
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else:
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if __debug__:
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self._note("%s.release(): non-final release", self)
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def __exit__(self, t, v, tb):
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self.release()
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# Internal methods used by condition variables
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def _acquire_restore(self, count_owner):
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count, owner = count_owner
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self.__block.acquire()
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self.__count = count
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self.__owner = owner
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if __debug__:
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self._note("%s._acquire_restore()", self)
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def _release_save(self):
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if __debug__:
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self._note("%s._release_save()", self)
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count = self.__count
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self.__count = 0
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owner = self.__owner
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self.__owner = None
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self.__block.release()
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return (count, owner)
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def _is_owned(self):
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return self.__owner == _get_ident()
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def Condition(*args, **kwargs):
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"""Factory function that returns a new condition variable object.
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A condition variable allows one or more threads to wait until they are
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notified by another thread.
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If the lock argument is given and not None, it must be a Lock or RLock
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object, and it is used as the underlying lock. Otherwise, a new RLock object
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is created and used as the underlying lock.
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"""
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return _Condition(*args, **kwargs)
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class _Condition(_Verbose):
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"""Condition variables allow one or more threads to wait until they are
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notified by another thread.
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"""
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def __init__(self, lock=None, verbose=None):
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_Verbose.__init__(self, verbose)
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if lock is None:
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lock = RLock()
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self.__lock = lock
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# Export the lock's acquire() and release() methods
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self.acquire = lock.acquire
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self.release = lock.release
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# If the lock defines _release_save() and/or _acquire_restore(),
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# these override the default implementations (which just call
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# release() and acquire() on the lock). Ditto for _is_owned().
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try:
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self._release_save = lock._release_save
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except AttributeError:
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pass
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try:
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self._acquire_restore = lock._acquire_restore
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except AttributeError:
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pass
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try:
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self._is_owned = lock._is_owned
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except AttributeError:
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pass
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self.__waiters = []
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def __enter__(self):
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return self.__lock.__enter__()
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def __exit__(self, *args):
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return self.__lock.__exit__(*args)
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def __repr__(self):
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return "<Condition(%s, %d)>" % (self.__lock, len(self.__waiters))
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def _release_save(self):
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self.__lock.release() # No state to save
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def _acquire_restore(self, x):
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self.__lock.acquire() # Ignore saved state
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def _is_owned(self):
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# Return True if lock is owned by current_thread.
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# This method is called only if __lock doesn't have _is_owned().
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if self.__lock.acquire(0):
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self.__lock.release()
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return False
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else:
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return True
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def wait(self, timeout=None):
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"""Wait until notified or until a timeout occurs.
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If the calling thread has not acquired the lock when this method is
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called, a RuntimeError is raised.
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This method releases the underlying lock, and then blocks until it is
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awakened by a notify() or notifyAll() call for the same condition
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variable in another thread, or until the optional timeout occurs. Once
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awakened or timed out, it re-acquires the lock and returns.
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When the timeout argument is present and not None, it should be a
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floating point number specifying a timeout for the operation in seconds
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(or fractions thereof).
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When the underlying lock is an RLock, it is not released using its
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release() method, since this may not actually unlock the lock when it
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was acquired multiple times recursively. Instead, an internal interface
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of the RLock class is used, which really unlocks it even when it has
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been recursively acquired several times. Another internal interface is
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then used to restore the recursion level when the lock is reacquired.
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"""
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if not self._is_owned():
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raise RuntimeError("cannot wait on un-acquired lock")
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waiter = _allocate_lock()
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waiter.acquire()
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self.__waiters.append(waiter)
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saved_state = self._release_save()
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try: # restore state no matter what (e.g., KeyboardInterrupt)
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if timeout is None:
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waiter.acquire()
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if __debug__:
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self._note("%s.wait(): got it", self)
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else:
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# Balancing act: We can't afford a pure busy loop, so we
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# have to sleep; but if we sleep the whole timeout time,
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# we'll be unresponsive. The scheme here sleeps very
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# little at first, longer as time goes on, but never longer
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# than 20 times per second (or the timeout time remaining).
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endtime = _time() + timeout
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delay = 0.0005 # 500 us -> initial delay of 1 ms
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while True:
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gotit = waiter.acquire(0)
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if gotit:
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break
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remaining = endtime - _time()
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if remaining <= 0:
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break
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delay = min(delay * 2, remaining, .05)
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_sleep(delay)
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if not gotit:
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if __debug__:
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self._note("%s.wait(%s): timed out", self, timeout)
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try:
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self.__waiters.remove(waiter)
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except ValueError:
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pass
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else:
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if __debug__:
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self._note("%s.wait(%s): got it", self, timeout)
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finally:
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self._acquire_restore(saved_state)
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def notify(self, n=1):
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"""Wake up one or more threads waiting on this condition, if any.
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If the calling thread has not acquired the lock when this method is
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called, a RuntimeError is raised.
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This method wakes up at most n of the threads waiting for the condition
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variable; it is a no-op if no threads are waiting.
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"""
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if not self._is_owned():
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raise RuntimeError("cannot notify on un-acquired lock")
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__waiters = self.__waiters
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waiters = __waiters[:n]
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if not waiters:
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if __debug__:
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self._note("%s.notify(): no waiters", self)
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return
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self._note("%s.notify(): notifying %d waiter%s", self, n,
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n!=1 and "s" or "")
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for waiter in waiters:
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waiter.release()
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try:
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__waiters.remove(waiter)
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except ValueError:
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pass
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def notifyAll(self):
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"""Wake up all threads waiting on this condition.
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If the calling thread has not acquired the lock when this method
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is called, a RuntimeError is raised.
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"""
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self.notify(len(self.__waiters))
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notify_all = notifyAll
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def Semaphore(*args, **kwargs):
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"""A factory function that returns a new semaphore.
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Semaphores manage a counter representing the number of release() calls minus
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the number of acquire() calls, plus an initial value. The acquire() method
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blocks if necessary until it can return without making the counter
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negative. If not given, value defaults to 1.
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"""
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return _Semaphore(*args, **kwargs)
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class _Semaphore(_Verbose):
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"""Semaphores manage a counter representing the number of release() calls
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minus the number of acquire() calls, plus an initial value. The acquire()
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method blocks if necessary until it can return without making the counter
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negative. If not given, value defaults to 1.
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"""
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# After Tim Peters' semaphore class, but not quite the same (no maximum)
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def __init__(self, value=1, verbose=None):
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if value < 0:
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raise ValueError("semaphore initial value must be >= 0")
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_Verbose.__init__(self, verbose)
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self.__cond = Condition(Lock())
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self.__value = value
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def acquire(self, blocking=1):
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"""Acquire a semaphore, decrementing the internal counter by one.
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When invoked without arguments: if the internal counter is larger than
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zero on entry, decrement it by one and return immediately. If it is zero
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on entry, block, waiting until some other thread has called release() to
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make it larger than zero. This is done with proper interlocking so that
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if multiple acquire() calls are blocked, release() will wake exactly one
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of them up. The implementation may pick one at random, so the order in
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which blocked threads are awakened should not be relied on. There is no
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return value in this case.
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When invoked with blocking set to true, do the same thing as when called
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without arguments, and return true.
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When invoked with blocking set to false, do not block. If a call without
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an argument would block, return false immediately; otherwise, do the
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same thing as when called without arguments, and return true.
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"""
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rc = False
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with self.__cond:
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while self.__value == 0:
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if not blocking:
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break
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if __debug__:
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self._note("%s.acquire(%s): blocked waiting, value=%s",
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self, blocking, self.__value)
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self.__cond.wait()
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else:
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self.__value = self.__value - 1
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if __debug__:
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self._note("%s.acquire: success, value=%s",
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self, self.__value)
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rc = True
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return rc
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__enter__ = acquire
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def release(self):
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"""Release a semaphore, incrementing the internal counter by one.
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When the counter is zero on entry and another thread is waiting for it
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to become larger than zero again, wake up that thread.
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"""
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with self.__cond:
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self.__value = self.__value + 1
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if __debug__:
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self._note("%s.release: success, value=%s",
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self, self.__value)
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self.__cond.notify()
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def __exit__(self, t, v, tb):
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self.release()
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|
|
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def BoundedSemaphore(*args, **kwargs):
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"""A factory function that returns a new bounded semaphore.
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A bounded semaphore checks to make sure its current value doesn't exceed its
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initial value. If it does, ValueError is raised. In most situations
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semaphores are used to guard resources with limited capacity.
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If the semaphore is released too many times it's a sign of a bug. If not
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given, value defaults to 1.
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Like regular semaphores, bounded semaphores manage a counter representing
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the number of release() calls minus the number of acquire() calls, plus an
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initial value. The acquire() method blocks if necessary until it can return
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without making the counter negative. If not given, value defaults to 1.
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"""
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return _BoundedSemaphore(*args, **kwargs)
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|
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class _BoundedSemaphore(_Semaphore):
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"""A bounded semaphore checks to make sure its current value doesn't exceed
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its initial value. If it does, ValueError is raised. In most situations
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semaphores are used to guard resources with limited capacity.
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"""
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|
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def __init__(self, value=1, verbose=None):
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_Semaphore.__init__(self, value, verbose)
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self._initial_value = value
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|
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def release(self):
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"""Release a semaphore, incrementing the internal counter by one.
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When the counter is zero on entry and another thread is waiting for it
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to become larger than zero again, wake up that thread.
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|
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If the number of releases exceeds the number of acquires,
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raise a ValueError.
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"""
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with self._Semaphore__cond:
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if self._Semaphore__value >= self._initial_value:
|
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raise ValueError("Semaphore released too many times")
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self._Semaphore__value += 1
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self._Semaphore__cond.notify()
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|
|
|
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def Event(*args, **kwargs):
|
|
"""A factory function that returns a new event.
|
|
|
|
Events manage a flag that can be set to true with the set() method and reset
|
|
to false with the clear() method. The wait() method blocks until the flag is
|
|
true.
|
|
|
|
"""
|
|
return _Event(*args, **kwargs)
|
|
|
|
class _Event(_Verbose):
|
|
"""A factory function that returns a new event object. An event manages a
|
|
flag that can be set to true with the set() method and reset to false
|
|
with the clear() method. The wait() method blocks until the flag is true.
|
|
|
|
"""
|
|
|
|
# After Tim Peters' event class (without is_posted())
|
|
|
|
def __init__(self, verbose=None):
|
|
_Verbose.__init__(self, verbose)
|
|
self.__cond = Condition(Lock())
|
|
self.__flag = False
|
|
|
|
def _reset_internal_locks(self):
|
|
# private! called by Thread._reset_internal_locks by _after_fork()
|
|
self.__cond.__init__()
|
|
|
|
def isSet(self):
|
|
'Return true if and only if the internal flag is true.'
|
|
return self.__flag
|
|
|
|
is_set = isSet
|
|
|
|
def set(self):
|
|
"""Set the internal flag to true.
|
|
|
|
All threads waiting for the flag to become true are awakened. Threads
|
|
that call wait() once the flag is true will not block at all.
|
|
|
|
"""
|
|
self.__cond.acquire()
|
|
try:
|
|
self.__flag = True
|
|
self.__cond.notify_all()
|
|
finally:
|
|
self.__cond.release()
|
|
|
|
def clear(self):
|
|
"""Reset the internal flag to false.
|
|
|
|
Subsequently, threads calling wait() will block until set() is called to
|
|
set the internal flag to true again.
|
|
|
|
"""
|
|
self.__cond.acquire()
|
|
try:
|
|
self.__flag = False
|
|
finally:
|
|
self.__cond.release()
|
|
|
|
def wait(self, timeout=None):
|
|
"""Block until the internal flag is true.
|
|
|
|
If the internal flag is true on entry, return immediately. Otherwise,
|
|
block until another thread calls set() to set the flag to true, or until
|
|
the optional timeout occurs.
|
|
|
|
When the timeout argument is present and not None, it should be a
|
|
floating point number specifying a timeout for the operation in seconds
|
|
(or fractions thereof).
|
|
|
|
This method returns the internal flag on exit, so it will always return
|
|
True except if a timeout is given and the operation times out.
|
|
|
|
"""
|
|
self.__cond.acquire()
|
|
try:
|
|
if not self.__flag:
|
|
self.__cond.wait(timeout)
|
|
return self.__flag
|
|
finally:
|
|
self.__cond.release()
|
|
|
|
# Helper to generate new thread names
|
|
_counter = _count().next
|
|
_counter() # Consume 0 so first non-main thread has id 1.
|
|
def _newname(template="Thread-%d"):
|
|
return template % _counter()
|
|
|
|
# Active thread administration
|
|
_active_limbo_lock = _allocate_lock()
|
|
_active = {} # maps thread id to Thread object
|
|
_limbo = {}
|
|
|
|
|
|
# Main class for threads
|
|
|
|
class Thread(_Verbose):
|
|
"""A class that represents a thread of control.
|
|
|
|
This class can be safely subclassed in a limited fashion.
|
|
|
|
"""
|
|
__initialized = False
|
|
# Need to store a reference to sys.exc_info for printing
|
|
# out exceptions when a thread tries to use a global var. during interp.
|
|
# shutdown and thus raises an exception about trying to perform some
|
|
# operation on/with a NoneType
|
|
__exc_info = _sys.exc_info
|
|
# Keep sys.exc_clear too to clear the exception just before
|
|
# allowing .join() to return.
|
|
__exc_clear = _sys.exc_clear
|
|
|
|
def __init__(self, group=None, target=None, name=None,
|
|
args=(), kwargs=None, verbose=None):
|
|
"""This constructor should always be called with keyword arguments. Arguments are:
|
|
|
|
*group* should be None; reserved for future extension when a ThreadGroup
|
|
class is implemented.
|
|
|
|
*target* is the callable object to be invoked by the run()
|
|
method. Defaults to None, meaning nothing is called.
|
|
|
|
*name* is the thread name. By default, a unique name is constructed of
|
|
the form "Thread-N" where N is a small decimal number.
|
|
|
|
*args* is the argument tuple for the target invocation. Defaults to ().
|
|
|
|
*kwargs* is a dictionary of keyword arguments for the target
|
|
invocation. Defaults to {}.
|
|
|
|
If a subclass overrides the constructor, it must make sure to invoke
|
|
the base class constructor (Thread.__init__()) before doing anything
|
|
else to the thread.
|
|
|
|
"""
|
|
assert group is None, "group argument must be None for now"
|
|
_Verbose.__init__(self, verbose)
|
|
if kwargs is None:
|
|
kwargs = {}
|
|
self.__target = target
|
|
self.__name = str(name or _newname())
|
|
self.__args = args
|
|
self.__kwargs = kwargs
|
|
self.__daemonic = self._set_daemon()
|
|
self.__ident = None
|
|
self.__started = Event()
|
|
self.__stopped = False
|
|
self.__block = Condition(Lock())
|
|
self.__initialized = True
|
|
# sys.stderr is not stored in the class like
|
|
# sys.exc_info since it can be changed between instances
|
|
self.__stderr = _sys.stderr
|
|
|
|
def _reset_internal_locks(self):
|
|
# private! Called by _after_fork() to reset our internal locks as
|
|
# they may be in an invalid state leading to a deadlock or crash.
|
|
if hasattr(self, '_Thread__block'): # DummyThread deletes self.__block
|
|
self.__block.__init__()
|
|
self.__started._reset_internal_locks()
|
|
|
|
@property
|
|
def _block(self):
|
|
# used by a unittest
|
|
return self.__block
|
|
|
|
def _set_daemon(self):
|
|
# Overridden in _MainThread and _DummyThread
|
|
return current_thread().daemon
|
|
|
|
def __repr__(self):
|
|
assert self.__initialized, "Thread.__init__() was not called"
|
|
status = "initial"
|
|
if self.__started.is_set():
|
|
status = "started"
|
|
if self.__stopped:
|
|
status = "stopped"
|
|
if self.__daemonic:
|
|
status += " daemon"
|
|
if self.__ident is not None:
|
|
status += " %s" % self.__ident
|
|
return "<%s(%s, %s)>" % (self.__class__.__name__, self.__name, status)
|
|
|
|
def start(self):
|
|
"""Start the thread's activity.
|
|
|
|
It must be called at most once per thread object. It arranges for the
|
|
object's run() method to be invoked in a separate thread of control.
|
|
|
|
This method will raise a RuntimeError if called more than once on the
|
|
same thread object.
|
|
|
|
"""
|
|
if not self.__initialized:
|
|
raise RuntimeError("thread.__init__() not called")
|
|
if self.__started.is_set():
|
|
raise RuntimeError("threads can only be started once")
|
|
if __debug__:
|
|
self._note("%s.start(): starting thread", self)
|
|
with _active_limbo_lock:
|
|
_limbo[self] = self
|
|
try:
|
|
_start_new_thread(self.__bootstrap, ())
|
|
except Exception:
|
|
with _active_limbo_lock:
|
|
del _limbo[self]
|
|
raise
|
|
self.__started.wait()
|
|
|
|
def run(self):
|
|
"""Method representing the thread's activity.
|
|
|
|
You may override this method in a subclass. The standard run() method
|
|
invokes the callable object passed to the object's constructor as the
|
|
target argument, if any, with sequential and keyword arguments taken
|
|
from the args and kwargs arguments, respectively.
|
|
|
|
"""
|
|
try:
|
|
if self.__target:
|
|
self.__target(*self.__args, **self.__kwargs)
|
|
finally:
|
|
# Avoid a refcycle if the thread is running a function with
|
|
# an argument that has a member that points to the thread.
|
|
del self.__target, self.__args, self.__kwargs
|
|
|
|
def __bootstrap(self):
|
|
# Wrapper around the real bootstrap code that ignores
|
|
# exceptions during interpreter cleanup. Those typically
|
|
# happen when a daemon thread wakes up at an unfortunate
|
|
# moment, finds the world around it destroyed, and raises some
|
|
# random exception *** while trying to report the exception in
|
|
# __bootstrap_inner() below ***. Those random exceptions
|
|
# don't help anybody, and they confuse users, so we suppress
|
|
# them. We suppress them only when it appears that the world
|
|
# indeed has already been destroyed, so that exceptions in
|
|
# __bootstrap_inner() during normal business hours are properly
|
|
# reported. Also, we only suppress them for daemonic threads;
|
|
# if a non-daemonic encounters this, something else is wrong.
|
|
try:
|
|
self.__bootstrap_inner()
|
|
except:
|
|
if self.__daemonic and _sys is None:
|
|
return
|
|
raise
|
|
|
|
def _set_ident(self):
|
|
self.__ident = _get_ident()
|
|
|
|
def __bootstrap_inner(self):
|
|
try:
|
|
self._set_ident()
|
|
self.__started.set()
|
|
with _active_limbo_lock:
|
|
_active[self.__ident] = self
|
|
del _limbo[self]
|
|
if __debug__:
|
|
self._note("%s.__bootstrap(): thread started", self)
|
|
|
|
if _trace_hook:
|
|
self._note("%s.__bootstrap(): registering trace hook", self)
|
|
_sys.settrace(_trace_hook)
|
|
if _profile_hook:
|
|
self._note("%s.__bootstrap(): registering profile hook", self)
|
|
_sys.setprofile(_profile_hook)
|
|
|
|
try:
|
|
self.run()
|
|
except SystemExit:
|
|
if __debug__:
|
|
self._note("%s.__bootstrap(): raised SystemExit", self)
|
|
except:
|
|
if __debug__:
|
|
self._note("%s.__bootstrap(): unhandled exception", self)
|
|
# If sys.stderr is no more (most likely from interpreter
|
|
# shutdown) use self.__stderr. Otherwise still use sys (as in
|
|
# _sys) in case sys.stderr was redefined since the creation of
|
|
# self.
|
|
if _sys and _sys.stderr is not None:
|
|
print>>_sys.stderr, ("Exception in thread %s:\n%s" %
|
|
(self.name, _format_exc()))
|
|
elif self.__stderr is not None:
|
|
# Do the best job possible w/o a huge amt. of code to
|
|
# approximate a traceback (code ideas from
|
|
# Lib/traceback.py)
|
|
exc_type, exc_value, exc_tb = self.__exc_info()
|
|
try:
|
|
print>>self.__stderr, (
|
|
"Exception in thread " + self.name +
|
|
" (most likely raised during interpreter shutdown):")
|
|
print>>self.__stderr, (
|
|
"Traceback (most recent call last):")
|
|
while exc_tb:
|
|
print>>self.__stderr, (
|
|
' File "%s", line %s, in %s' %
|
|
(exc_tb.tb_frame.f_code.co_filename,
|
|
exc_tb.tb_lineno,
|
|
exc_tb.tb_frame.f_code.co_name))
|
|
exc_tb = exc_tb.tb_next
|
|
print>>self.__stderr, ("%s: %s" % (exc_type, exc_value))
|
|
# Make sure that exc_tb gets deleted since it is a memory
|
|
# hog; deleting everything else is just for thoroughness
|
|
finally:
|
|
del exc_type, exc_value, exc_tb
|
|
else:
|
|
if __debug__:
|
|
self._note("%s.__bootstrap(): normal return", self)
|
|
finally:
|
|
# Prevent a race in
|
|
# test_threading.test_no_refcycle_through_target when
|
|
# the exception keeps the target alive past when we
|
|
# assert that it's dead.
|
|
self.__exc_clear()
|
|
finally:
|
|
with _active_limbo_lock:
|
|
self.__stop()
|
|
try:
|
|
# We don't call self.__delete() because it also
|
|
# grabs _active_limbo_lock.
|
|
del _active[_get_ident()]
|
|
except:
|
|
pass
|
|
|
|
def __stop(self):
|
|
# DummyThreads delete self.__block, but they have no waiters to
|
|
# notify anyway (join() is forbidden on them).
|
|
if not hasattr(self, '_Thread__block'):
|
|
return
|
|
self.__block.acquire()
|
|
self.__stopped = True
|
|
self.__block.notify_all()
|
|
self.__block.release()
|
|
|
|
def __delete(self):
|
|
"Remove current thread from the dict of currently running threads."
|
|
|
|
# Notes about running with dummy_thread:
|
|
#
|
|
# Must take care to not raise an exception if dummy_thread is being
|
|
# used (and thus this module is being used as an instance of
|
|
# dummy_threading). dummy_thread.get_ident() always returns -1 since
|
|
# there is only one thread if dummy_thread is being used. Thus
|
|
# len(_active) is always <= 1 here, and any Thread instance created
|
|
# overwrites the (if any) thread currently registered in _active.
|
|
#
|
|
# An instance of _MainThread is always created by 'threading'. This
|
|
# gets overwritten the instant an instance of Thread is created; both
|
|
# threads return -1 from dummy_thread.get_ident() and thus have the
|
|
# same key in the dict. So when the _MainThread instance created by
|
|
# 'threading' tries to clean itself up when atexit calls this method
|
|
# it gets a KeyError if another Thread instance was created.
|
|
#
|
|
# This all means that KeyError from trying to delete something from
|
|
# _active if dummy_threading is being used is a red herring. But
|
|
# since it isn't if dummy_threading is *not* being used then don't
|
|
# hide the exception.
|
|
|
|
try:
|
|
with _active_limbo_lock:
|
|
del _active[_get_ident()]
|
|
# There must not be any python code between the previous line
|
|
# and after the lock is released. Otherwise a tracing function
|
|
# could try to acquire the lock again in the same thread, (in
|
|
# current_thread()), and would block.
|
|
except KeyError:
|
|
if 'dummy_threading' not in _sys.modules:
|
|
raise
|
|
|
|
def join(self, timeout=None):
|
|
"""Wait until the thread terminates.
|
|
|
|
This blocks the calling thread until the thread whose join() method is
|
|
called terminates -- either normally or through an unhandled exception
|
|
or until the optional timeout occurs.
|
|
|
|
When the timeout argument is present and not None, it should be a
|
|
floating point number specifying a timeout for the operation in seconds
|
|
(or fractions thereof). As join() always returns None, you must call
|
|
isAlive() after join() to decide whether a timeout happened -- if the
|
|
thread is still alive, the join() call timed out.
|
|
|
|
When the timeout argument is not present or None, the operation will
|
|
block until the thread terminates.
|
|
|
|
A thread can be join()ed many times.
|
|
|
|
join() raises a RuntimeError if an attempt is made to join the current
|
|
thread as that would cause a deadlock. It is also an error to join() a
|
|
thread before it has been started and attempts to do so raises the same
|
|
exception.
|
|
|
|
"""
|
|
if not self.__initialized:
|
|
raise RuntimeError("Thread.__init__() not called")
|
|
if not self.__started.is_set():
|
|
raise RuntimeError("cannot join thread before it is started")
|
|
if self is current_thread():
|
|
raise RuntimeError("cannot join current thread")
|
|
|
|
if __debug__:
|
|
if not self.__stopped:
|
|
self._note("%s.join(): waiting until thread stops", self)
|
|
self.__block.acquire()
|
|
try:
|
|
if timeout is None:
|
|
while not self.__stopped:
|
|
self.__block.wait()
|
|
if __debug__:
|
|
self._note("%s.join(): thread stopped", self)
|
|
else:
|
|
deadline = _time() + timeout
|
|
while not self.__stopped:
|
|
delay = deadline - _time()
|
|
if delay <= 0:
|
|
if __debug__:
|
|
self._note("%s.join(): timed out", self)
|
|
break
|
|
self.__block.wait(delay)
|
|
else:
|
|
if __debug__:
|
|
self._note("%s.join(): thread stopped", self)
|
|
finally:
|
|
self.__block.release()
|
|
|
|
@property
|
|
def name(self):
|
|
"""A string used for identification purposes only.
|
|
|
|
It has no semantics. Multiple threads may be given the same name. The
|
|
initial name is set by the constructor.
|
|
|
|
"""
|
|
assert self.__initialized, "Thread.__init__() not called"
|
|
return self.__name
|
|
|
|
@name.setter
|
|
def name(self, name):
|
|
assert self.__initialized, "Thread.__init__() not called"
|
|
self.__name = str(name)
|
|
|
|
@property
|
|
def ident(self):
|
|
"""Thread identifier of this thread or None if it has not been started.
|
|
|
|
This is a nonzero integer. See the thread.get_ident() function. Thread
|
|
identifiers may be recycled when a thread exits and another thread is
|
|
created. The identifier is available even after the thread has exited.
|
|
|
|
"""
|
|
assert self.__initialized, "Thread.__init__() not called"
|
|
return self.__ident
|
|
|
|
def isAlive(self):
|
|
"""Return whether the thread is alive.
|
|
|
|
This method returns True just before the run() method starts until just
|
|
after the run() method terminates. The module function enumerate()
|
|
returns a list of all alive threads.
|
|
|
|
"""
|
|
assert self.__initialized, "Thread.__init__() not called"
|
|
return self.__started.is_set() and not self.__stopped
|
|
|
|
is_alive = isAlive
|
|
|
|
@property
|
|
def daemon(self):
|
|
"""A boolean value indicating whether this thread is a daemon thread (True) or not (False).
|
|
|
|
This must be set before start() is called, otherwise RuntimeError is
|
|
raised. Its initial value is inherited from the creating thread; the
|
|
main thread is not a daemon thread and therefore all threads created in
|
|
the main thread default to daemon = False.
|
|
|
|
The entire Python program exits when no alive non-daemon threads are
|
|
left.
|
|
|
|
"""
|
|
assert self.__initialized, "Thread.__init__() not called"
|
|
return self.__daemonic
|
|
|
|
@daemon.setter
|
|
def daemon(self, daemonic):
|
|
if not self.__initialized:
|
|
raise RuntimeError("Thread.__init__() not called")
|
|
if self.__started.is_set():
|
|
raise RuntimeError("cannot set daemon status of active thread");
|
|
self.__daemonic = daemonic
|
|
|
|
def isDaemon(self):
|
|
return self.daemon
|
|
|
|
def setDaemon(self, daemonic):
|
|
self.daemon = daemonic
|
|
|
|
def getName(self):
|
|
return self.name
|
|
|
|
def setName(self, name):
|
|
self.name = name
|
|
|
|
# The timer class was contributed by Itamar Shtull-Trauring
|
|
|
|
def Timer(*args, **kwargs):
|
|
"""Factory function to create a Timer object.
|
|
|
|
Timers call a function after a specified number of seconds:
|
|
|
|
t = Timer(30.0, f, args=[], kwargs={})
|
|
t.start()
|
|
t.cancel() # stop the timer's action if it's still waiting
|
|
|
|
"""
|
|
return _Timer(*args, **kwargs)
|
|
|
|
class _Timer(Thread):
|
|
"""Call a function after a specified number of seconds:
|
|
|
|
t = Timer(30.0, f, args=[], kwargs={})
|
|
t.start()
|
|
t.cancel() # stop the timer's action if it's still waiting
|
|
|
|
"""
|
|
|
|
def __init__(self, interval, function, args=[], kwargs={}):
|
|
Thread.__init__(self)
|
|
self.interval = interval
|
|
self.function = function
|
|
self.args = args
|
|
self.kwargs = kwargs
|
|
self.finished = Event()
|
|
|
|
def cancel(self):
|
|
"""Stop the timer if it hasn't finished yet"""
|
|
self.finished.set()
|
|
|
|
def run(self):
|
|
self.finished.wait(self.interval)
|
|
if not self.finished.is_set():
|
|
self.function(*self.args, **self.kwargs)
|
|
self.finished.set()
|
|
|
|
# Special thread class to represent the main thread
|
|
# This is garbage collected through an exit handler
|
|
|
|
class _MainThread(Thread):
|
|
|
|
def __init__(self):
|
|
Thread.__init__(self, name="MainThread")
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self._Thread__started.set()
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|
self._set_ident()
|
|
with _active_limbo_lock:
|
|
_active[_get_ident()] = self
|
|
|
|
def _set_daemon(self):
|
|
return False
|
|
|
|
def _exitfunc(self):
|
|
self._Thread__stop()
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|
t = _pickSomeNonDaemonThread()
|
|
if t:
|
|
if __debug__:
|
|
self._note("%s: waiting for other threads", self)
|
|
while t:
|
|
t.join()
|
|
t = _pickSomeNonDaemonThread()
|
|
if __debug__:
|
|
self._note("%s: exiting", self)
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|
self._Thread__delete()
|
|
|
|
def _pickSomeNonDaemonThread():
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|
for t in enumerate():
|
|
if not t.daemon and t.is_alive():
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|
return t
|
|
return None
|
|
|
|
|
|
# Dummy thread class to represent threads not started here.
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|
# These aren't garbage collected when they die, nor can they be waited for.
|
|
# If they invoke anything in threading.py that calls current_thread(), they
|
|
# leave an entry in the _active dict forever after.
|
|
# Their purpose is to return *something* from current_thread().
|
|
# They are marked as daemon threads so we won't wait for them
|
|
# when we exit (conform previous semantics).
|
|
|
|
class _DummyThread(Thread):
|
|
|
|
def __init__(self):
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|
Thread.__init__(self, name=_newname("Dummy-%d"))
|
|
|
|
# Thread.__block consumes an OS-level locking primitive, which
|
|
# can never be used by a _DummyThread. Since a _DummyThread
|
|
# instance is immortal, that's bad, so release this resource.
|
|
del self._Thread__block
|
|
|
|
self._Thread__started.set()
|
|
self._set_ident()
|
|
with _active_limbo_lock:
|
|
_active[_get_ident()] = self
|
|
|
|
def _set_daemon(self):
|
|
return True
|
|
|
|
def join(self, timeout=None):
|
|
assert False, "cannot join a dummy thread"
|
|
|
|
|
|
# Global API functions
|
|
|
|
def currentThread():
|
|
"""Return the current Thread object, corresponding to the caller's thread of control.
|
|
|
|
If the caller's thread of control was not created through the threading
|
|
module, a dummy thread object with limited functionality is returned.
|
|
|
|
"""
|
|
try:
|
|
return _active[_get_ident()]
|
|
except KeyError:
|
|
##print "current_thread(): no current thread for", _get_ident()
|
|
return _DummyThread()
|
|
|
|
current_thread = currentThread
|
|
|
|
def activeCount():
|
|
"""Return the number of Thread objects currently alive.
|
|
|
|
The returned count is equal to the length of the list returned by
|
|
enumerate().
|
|
|
|
"""
|
|
with _active_limbo_lock:
|
|
return len(_active) + len(_limbo)
|
|
|
|
active_count = activeCount
|
|
|
|
def _enumerate():
|
|
# Same as enumerate(), but without the lock. Internal use only.
|
|
return _active.values() + _limbo.values()
|
|
|
|
def enumerate():
|
|
"""Return a list of all Thread objects currently alive.
|
|
|
|
The list includes daemonic threads, dummy thread objects created by
|
|
current_thread(), and the main thread. It excludes terminated threads and
|
|
threads that have not yet been started.
|
|
|
|
"""
|
|
with _active_limbo_lock:
|
|
return _active.values() + _limbo.values()
|
|
|
|
from thread import stack_size
|
|
|
|
# Create the main thread object,
|
|
# and make it available for the interpreter
|
|
# (Py_Main) as threading._shutdown.
|
|
|
|
_shutdown = _MainThread()._exitfunc
|
|
|
|
# get thread-local implementation, either from the thread
|
|
# module, or from the python fallback
|
|
|
|
try:
|
|
from thread import _local as local
|
|
except ImportError:
|
|
from _threading_local import local
|
|
|
|
|
|
def _after_fork():
|
|
# This function is called by Python/ceval.c:PyEval_ReInitThreads which
|
|
# is called from PyOS_AfterFork. Here we cleanup threading module state
|
|
# that should not exist after a fork.
|
|
|
|
# Reset _active_limbo_lock, in case we forked while the lock was held
|
|
# by another (non-forked) thread. http://bugs.python.org/issue874900
|
|
global _active_limbo_lock
|
|
_active_limbo_lock = _allocate_lock()
|
|
|
|
# fork() only copied the current thread; clear references to others.
|
|
new_active = {}
|
|
current = current_thread()
|
|
with _active_limbo_lock:
|
|
for thread in _enumerate():
|
|
# Any lock/condition variable may be currently locked or in an
|
|
# invalid state, so we reinitialize them.
|
|
if hasattr(thread, '_reset_internal_locks'):
|
|
thread._reset_internal_locks()
|
|
if thread is current:
|
|
# There is only one active thread. We reset the ident to
|
|
# its new value since it can have changed.
|
|
ident = _get_ident()
|
|
thread._Thread__ident = ident
|
|
new_active[ident] = thread
|
|
else:
|
|
# All the others are already stopped.
|
|
thread._Thread__stop()
|
|
|
|
_limbo.clear()
|
|
_active.clear()
|
|
_active.update(new_active)
|
|
assert len(_active) == 1
|
|
|
|
|
|
# Self-test code
|
|
|
|
def _test():
|
|
|
|
class BoundedQueue(_Verbose):
|
|
|
|
def __init__(self, limit):
|
|
_Verbose.__init__(self)
|
|
self.mon = RLock()
|
|
self.rc = Condition(self.mon)
|
|
self.wc = Condition(self.mon)
|
|
self.limit = limit
|
|
self.queue = _deque()
|
|
|
|
def put(self, item):
|
|
self.mon.acquire()
|
|
while len(self.queue) >= self.limit:
|
|
self._note("put(%s): queue full", item)
|
|
self.wc.wait()
|
|
self.queue.append(item)
|
|
self._note("put(%s): appended, length now %d",
|
|
item, len(self.queue))
|
|
self.rc.notify()
|
|
self.mon.release()
|
|
|
|
def get(self):
|
|
self.mon.acquire()
|
|
while not self.queue:
|
|
self._note("get(): queue empty")
|
|
self.rc.wait()
|
|
item = self.queue.popleft()
|
|
self._note("get(): got %s, %d left", item, len(self.queue))
|
|
self.wc.notify()
|
|
self.mon.release()
|
|
return item
|
|
|
|
class ProducerThread(Thread):
|
|
|
|
def __init__(self, queue, quota):
|
|
Thread.__init__(self, name="Producer")
|
|
self.queue = queue
|
|
self.quota = quota
|
|
|
|
def run(self):
|
|
from random import random
|
|
counter = 0
|
|
while counter < self.quota:
|
|
counter = counter + 1
|
|
self.queue.put("%s.%d" % (self.name, counter))
|
|
_sleep(random() * 0.00001)
|
|
|
|
|
|
class ConsumerThread(Thread):
|
|
|
|
def __init__(self, queue, count):
|
|
Thread.__init__(self, name="Consumer")
|
|
self.queue = queue
|
|
self.count = count
|
|
|
|
def run(self):
|
|
while self.count > 0:
|
|
item = self.queue.get()
|
|
print item
|
|
self.count = self.count - 1
|
|
|
|
NP = 3
|
|
QL = 4
|
|
NI = 5
|
|
|
|
Q = BoundedQueue(QL)
|
|
P = []
|
|
for i in range(NP):
|
|
t = ProducerThread(Q, NI)
|
|
t.name = ("Producer-%d" % (i+1))
|
|
P.append(t)
|
|
C = ConsumerThread(Q, NI*NP)
|
|
for t in P:
|
|
t.start()
|
|
_sleep(0.000001)
|
|
C.start()
|
|
for t in P:
|
|
t.join()
|
|
C.join()
|
|
|
|
if __name__ == '__main__':
|
|
_test()
|