964 lines
31 KiB
Python
964 lines
31 KiB
Python
"""Thread module emulating a subset of Java's threading model."""
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import sys as _sys
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import _thread
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from time import sleep as _sleep
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try:
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from time import monotonic as _time
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except ImportError:
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from time import time as _time
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from traceback import format_exc as _format_exc
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from _weakrefset import WeakSet
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try:
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from _itertools import islice as _slice
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from _collections import deque as _deque
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except ImportError:
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from itertools import islice as _islice
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from collections import deque as _deque
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# Note regarding PEP 8 compliant names
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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. Those originaly names are not in any imminent danger of
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# being deprecated (even for Py3k),so this module provides them as an
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# alias for the PEP 8 compliant names
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# Note that using the new PEP 8 compliant names 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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__all__ = ['active_count', 'Condition', 'current_thread', 'enumerate', 'Event',
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'Lock', 'RLock', 'Semaphore', 'BoundedSemaphore', 'Thread', 'Barrier',
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'Timer', 'ThreadError', 'setprofile', 'settrace', 'local', 'stack_size']
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# Rename some stuff so "from threading import *" is safe
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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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try:
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_CRLock = _thread.RLock
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except AttributeError:
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_CRLock = None
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TIMEOUT_MAX = _thread.TIMEOUT_MAX
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del _thread
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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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global _profile_hook
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_profile_hook = func
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def settrace(func):
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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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if _CRLock is None:
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return _PyRLock(*args, **kwargs)
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return _CRLock(*args, **kwargs)
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class _RLock:
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def __init__(self):
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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=True, timeout=-1):
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me = get_ident()
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if self._owner == me:
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self._count += 1
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return 1
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rc = self._block.acquire(blocking, timeout)
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if rc:
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self._owner = me
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self._count = 1
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return rc
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__enter__ = acquire
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def release(self):
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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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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, state):
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self._block.acquire()
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self._count, self._owner = state
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def _release_save(self):
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if self._count == 0:
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raise RuntimeError("cannot release un-acquired lock")
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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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_PyRLock = _RLock
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class Condition:
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def __init__(self, lock=None):
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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 = _deque()
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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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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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gotit = True
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else:
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if timeout > 0:
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gotit = waiter.acquire(True, timeout)
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else:
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gotit = waiter.acquire(False)
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if not gotit:
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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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return gotit
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finally:
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self._acquire_restore(saved_state)
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def wait_for(self, predicate, timeout=None):
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endtime = None
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waittime = timeout
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result = predicate()
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while not result:
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if waittime is not None:
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if endtime is None:
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endtime = _time() + waittime
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else:
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waittime = endtime - _time()
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if waittime <= 0:
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break
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self.wait(waittime)
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result = predicate()
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return result
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def notify(self, n=1):
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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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all_waiters = self._waiters
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waiters_to_notify = _deque(_islice(all_waiters, n))
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if not waiters_to_notify:
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return
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for waiter in waiters_to_notify:
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waiter.release()
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try:
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all_waiters.remove(waiter)
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except ValueError:
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pass
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def notify_all(self):
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self.notify(len(self._waiters))
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notifyAll = notify_all
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class Semaphore:
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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):
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if value < 0:
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raise ValueError("semaphore initial value must be >= 0")
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self._cond = Condition(Lock())
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self._value = value
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def acquire(self, blocking=True, timeout=None):
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if not blocking and timeout is not None:
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raise ValueError("can't specify timeout for non-blocking acquire")
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rc = False
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endtime = None
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self._cond.acquire()
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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 timeout is not None:
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if endtime is None:
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endtime = _time() + timeout
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else:
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timeout = endtime - _time()
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if timeout <= 0:
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break
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self._cond.wait(timeout)
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else:
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self._value -= 1
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rc = True
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self._cond.release()
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return rc
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__enter__ = acquire
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def release(self):
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self._cond.acquire()
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self._value += 1
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self._cond.notify()
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self._cond.release()
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def __exit__(self, t, v, tb):
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self.release()
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class BoundedSemaphore(Semaphore):
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"""Semaphore that checks that # releases is <= # acquires"""
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def __init__(self, value=1):
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Semaphore.__init__(self, value)
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self._initial_value = value
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def release(self):
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if self._value >= self._initial_value:
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raise ValueError("Semaphore released too many times")
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return Semaphore.release(self)
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class Event:
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# After Tim Peters' event class (without is_posted())
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def __init__(self):
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self._cond = Condition(Lock())
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self._flag = False
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def _reset_internal_locks(self):
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# private! called by Thread._reset_internal_locks by _after_fork()
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self._cond.__init__()
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def is_set(self):
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return self._flag
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isSet = is_set
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def set(self):
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self._cond.acquire()
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try:
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self._flag = True
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self._cond.notify_all()
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finally:
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self._cond.release()
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def clear(self):
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self._cond.acquire()
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try:
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self._flag = False
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finally:
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self._cond.release()
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def wait(self, timeout=None):
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self._cond.acquire()
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try:
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signaled = self._flag
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if not signaled:
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signaled = self._cond.wait(timeout)
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return signaled
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finally:
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self._cond.release()
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# A barrier class. Inspired in part by the pthread_barrier_* api and
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# the CyclicBarrier class from Java. See
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# http://sourceware.org/pthreads-win32/manual/pthread_barrier_init.html and
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# http://java.sun.com/j2se/1.5.0/docs/api/java/util/concurrent/
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# CyclicBarrier.html
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# for information.
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# We maintain two main states, 'filling' and 'draining' enabling the barrier
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# to be cyclic. Threads are not allowed into it until it has fully drained
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# since the previous cycle. In addition, a 'resetting' state exists which is
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# similar to 'draining' except that threads leave with a BrokenBarrierError,
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# and a 'broken' state in which all threads get the exception.
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class Barrier:
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"""
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Barrier. Useful for synchronizing a fixed number of threads
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at known synchronization points. Threads block on 'wait()' and are
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simultaneously once they have all made that call.
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"""
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def __init__(self, parties, action=None, timeout=None):
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"""
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Create a barrier, initialised to 'parties' threads.
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'action' is a callable which, when supplied, will be called
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by one of the threads after they have all entered the
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barrier and just prior to releasing them all.
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If a 'timeout' is provided, it is uses as the default for
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all subsequent 'wait()' calls.
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"""
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self._cond = Condition(Lock())
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self._action = action
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self._timeout = timeout
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self._parties = parties
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self._state = 0 #0 filling, 1, draining, -1 resetting, -2 broken
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self._count = 0
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def wait(self, timeout=None):
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"""
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Wait for the barrier. When the specified number of threads have
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started waiting, they are all simultaneously awoken. If an 'action'
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was provided for the barrier, one of the threads will have executed
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that callback prior to returning.
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Returns an individual index number from 0 to 'parties-1'.
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"""
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if timeout is None:
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timeout = self._timeout
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with self._cond:
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self._enter() # Block while the barrier drains.
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index = self._count
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self._count += 1
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try:
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if index + 1 == self._parties:
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# We release the barrier
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self._release()
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else:
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# We wait until someone releases us
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self._wait(timeout)
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return index
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finally:
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self._count -= 1
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# Wake up any threads waiting for barrier to drain.
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self._exit()
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# Block until the barrier is ready for us, or raise an exception
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# if it is broken.
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def _enter(self):
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while self._state in (-1, 1):
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# It is draining or resetting, wait until done
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self._cond.wait()
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#see if the barrier is in a broken state
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if self._state < 0:
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raise BrokenBarrierError
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assert self._state == 0
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# Optionally run the 'action' and release the threads waiting
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# in the barrier.
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def _release(self):
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try:
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if self._action:
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self._action()
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# enter draining state
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self._state = 1
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self._cond.notify_all()
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except:
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#an exception during the _action handler. Break and reraise
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self._break()
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raise
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# Wait in the barrier until we are relased. Raise an exception
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# if the barrier is reset or broken.
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def _wait(self, timeout):
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if not self._cond.wait_for(lambda : self._state != 0, timeout):
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#timed out. Break the barrier
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self._break()
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raise BrokenBarrierError
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if self._state < 0:
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raise BrokenBarrierError
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assert self._state == 1
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# If we are the last thread to exit the barrier, signal any threads
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# waiting for the barrier to drain.
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def _exit(self):
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if self._count == 0:
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if self._state in (-1, 1):
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#resetting or draining
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self._state = 0
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self._cond.notify_all()
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|
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def reset(self):
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"""
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Reset the barrier to the initial state.
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Any threads currently waiting will get the BrokenBarrier exception
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raised.
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"""
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with self._cond:
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if self._count > 0:
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if self._state == 0:
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#reset the barrier, waking up threads
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self._state = -1
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elif self._state == -2:
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#was broken, set it to reset state
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#which clears when the last thread exits
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self._state = -1
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else:
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self._state = 0
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self._cond.notify_all()
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|
|
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def abort(self):
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"""
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Place the barrier into a 'broken' state.
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Useful in case of error. Any currently waiting threads and
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threads attempting to 'wait()' will have BrokenBarrierError
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raised.
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"""
|
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with self._cond:
|
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self._break()
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|
|
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def _break(self):
|
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# An internal error was detected. The barrier is set to
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# a broken state all parties awakened.
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self._state = -2
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self._cond.notify_all()
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|
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@property
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def parties(self):
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"""
|
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Return the number of threads required to trip the barrier.
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"""
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return self._parties
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|
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@property
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def n_waiting(self):
|
|
"""
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Return the number of threads that are currently waiting at the barrier.
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"""
|
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# We don't need synchronization here since this is an ephemeral result
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# anyway. It returns the correct value in the steady state.
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if self._state == 0:
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return self._count
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return 0
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|
|
|
@property
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def broken(self):
|
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"""
|
|
Return True if the barrier is in a broken state
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"""
|
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return self._state == -2
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|
|
|
#exception raised by the Barrier class
|
|
class BrokenBarrierError(RuntimeError): pass
|
|
|
|
|
|
# Helper to generate new thread names
|
|
_counter = 0
|
|
def _newname(template="Thread-%d"):
|
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global _counter
|
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_counter += 1
|
|
return template % _counter
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|
|
|
# Active thread administration
|
|
_active_limbo_lock = _allocate_lock()
|
|
_active = {} # maps thread id to Thread object
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_limbo = {}
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|
|
|
# For debug and leak testing
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|
_dangling = WeakSet()
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|
|
|
# Main class for threads
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|
|
|
class Thread:
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|
|
|
__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
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|
# Keep sys.exc_clear too to clear the exception just before
|
|
# allowing .join() to return.
|
|
#XXX __exc_clear = _sys.exc_clear
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|
|
|
def __init__(self, group=None, target=None, name=None,
|
|
args=(), kwargs=None, *, daemon=None):
|
|
assert group is None, "group argument must be None for now"
|
|
if kwargs is None:
|
|
kwargs = {}
|
|
self._target = target
|
|
self._name = str(name or _newname())
|
|
self._args = args
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|
self._kwargs = kwargs
|
|
if daemon is not None:
|
|
self._daemonic = daemon
|
|
else:
|
|
self._daemonic = current_thread().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
|
|
_dangling.add(self)
|
|
|
|
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, '_block'): # DummyThread deletes _block
|
|
self._block.__init__()
|
|
self._started._reset_internal_locks()
|
|
|
|
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):
|
|
if not self._initialized:
|
|
raise RuntimeError("thread.__init__() not called")
|
|
|
|
if self._started.is_set():
|
|
raise RuntimeError("threads can only be started once")
|
|
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):
|
|
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 _trace_hook:
|
|
_sys.settrace(_trace_hook)
|
|
if _profile_hook:
|
|
_sys.setprofile(_profile_hook)
|
|
|
|
try:
|
|
self.run()
|
|
except SystemExit:
|
|
pass
|
|
except:
|
|
# 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:
|
|
_sys.stderr.write("Exception in thread %s:\n%s\n" %
|
|
(self.name, _format_exc()))
|
|
else:
|
|
# 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((
|
|
"Exception in thread " + self.name +
|
|
" (most likely raised during interpreter shutdown):"), file=self._stderr)
|
|
print((
|
|
"Traceback (most recent call last):"), file=self._stderr)
|
|
while exc_tb:
|
|
print((
|
|
' 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)), file=self._stderr)
|
|
exc_tb = exc_tb.tb_next
|
|
print(("%s: %s" % (exc_type, exc_value)), file=self._stderr)
|
|
# 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
|
|
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.
|
|
#XXX self.__exc_clear()
|
|
pass
|
|
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):
|
|
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):
|
|
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")
|
|
|
|
self._block.acquire()
|
|
try:
|
|
if timeout is None:
|
|
while not self._stopped:
|
|
self._block.wait()
|
|
else:
|
|
deadline = _time() + timeout
|
|
while not self._stopped:
|
|
delay = deadline - _time()
|
|
if delay <= 0:
|
|
break
|
|
self._block.wait(delay)
|
|
finally:
|
|
self._block.release()
|
|
|
|
@property
|
|
def name(self):
|
|
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):
|
|
assert self._initialized, "Thread.__init__() not called"
|
|
return self._ident
|
|
|
|
def is_alive(self):
|
|
assert self._initialized, "Thread.__init__() not called"
|
|
return self._started.is_set() and not self._stopped
|
|
|
|
isAlive = is_alive
|
|
|
|
@property
|
|
def daemon(self):
|
|
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
|
|
|
|
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", daemon=False)
|
|
self._started.set()
|
|
self._set_ident()
|
|
with _active_limbo_lock:
|
|
_active[self._ident] = self
|
|
|
|
def _exitfunc(self):
|
|
self._stop()
|
|
t = _pickSomeNonDaemonThread()
|
|
while t:
|
|
t.join()
|
|
t = _pickSomeNonDaemonThread()
|
|
self._delete()
|
|
|
|
def _pickSomeNonDaemonThread():
|
|
for t in enumerate():
|
|
if not t.daemon and t.is_alive():
|
|
return t
|
|
return None
|
|
|
|
|
|
# Dummy thread class to represent threads not started here.
|
|
# 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):
|
|
Thread.__init__(self, name=_newname("Dummy-%d"), daemon=True)
|
|
|
|
# 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._block
|
|
|
|
self._started.set()
|
|
self._set_ident()
|
|
with _active_limbo_lock:
|
|
_active[self._ident] = self
|
|
|
|
def _stop(self):
|
|
pass
|
|
|
|
def join(self, timeout=None):
|
|
assert False, "cannot join a dummy thread"
|
|
|
|
|
|
# Global API functions
|
|
|
|
def current_thread():
|
|
try:
|
|
return _active[get_ident()]
|
|
except KeyError:
|
|
return _DummyThread()
|
|
|
|
currentThread = current_thread
|
|
|
|
def active_count():
|
|
with _active_limbo_lock:
|
|
return len(_active) + len(_limbo)
|
|
|
|
activeCount = active_count
|
|
|
|
def _enumerate():
|
|
# Same as enumerate(), but without the lock. Internal use only.
|
|
return list(_active.values()) + list(_limbo.values())
|
|
|
|
def enumerate():
|
|
with _active_limbo_lock:
|
|
return list(_active.values()) + list(_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 _active.values():
|
|
# Any lock/condition variable may be currently locked or in an
|
|
# invalid state, so we reinitialize them.
|
|
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._ident = ident
|
|
new_active[ident] = thread
|
|
else:
|
|
# All the others are already stopped.
|
|
thread._stop()
|
|
|
|
_limbo.clear()
|
|
_active.clear()
|
|
_active.update(new_active)
|
|
assert len(_active) == 1
|