cpython-withatomic / Lib / threading.py

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
"""Thread module emulating a subset of Java's threading model."""

import sys as _sys

try:
    import thread
except ImportError:
    del _sys.modules[__name__]
    raise

import warnings

from functools import wraps
from time import time as _time, sleep as _sleep
from traceback import format_exc as _format_exc
from collections import deque

# Note regarding PEP 8 compliant aliases
#  This threading model was originally inspired by Java, and inherited
# the convention of camelCase function and method names from that
# language. While those names are not in any imminent danger of being
# deprecated, starting with Python 2.6, the module now provides a
# PEP 8 compliant alias for any such method name.
# Using the new PEP 8 compliant names also facilitates substitution
# with the multiprocessing module, which doesn't provide the old
# Java inspired names.


# Rename some stuff so "from threading import *" is safe
__all__ = ['activeCount', 'active_count', 'Condition', 'currentThread',
           'current_thread', 'enumerate', 'Event',
           'Lock', 'RLock', 'Semaphore', 'BoundedSemaphore', 'Thread',
           'Timer', 'setprofile', 'settrace', 'local', 'stack_size']

_start_new_thread = thread.start_new_thread
_allocate_lock = thread.allocate_lock
_get_ident = thread.get_ident
ThreadError = thread.error
del thread


# sys.exc_clear is used to work around the fact that except blocks
# don't fully clear the exception until 3.0.
warnings.filterwarnings('ignore', category=DeprecationWarning,
                        module='threading', message='sys.exc_clear')

# Debug support (adapted from ihooks.py).
# All the major classes here derive from _Verbose.  We force that to
# be a new-style class so that all the major classes here are new-style.
# This helps debugging (type(instance) is more revealing for instances
# of new-style classes).

_VERBOSE = False

if __debug__:

    class _Verbose(object):

        def __init__(self, verbose=None):
            if verbose is None:
                verbose = _VERBOSE
            self.__verbose = verbose

        def _note(self, format, *args):
            if self.__verbose:
                format = format % args
                format = "%s: %s\n" % (
                    current_thread().name, format)
                _sys.stderr.write(format)

else:
    # Disable this when using "python -O"
    class _Verbose(object):
        def __init__(self, verbose=None):
            pass
        def _note(self, *args):
            pass

# Support for profile and trace hooks

_profile_hook = None
_trace_hook = None

def setprofile(func):
    global _profile_hook
    _profile_hook = func

def settrace(func):
    global _trace_hook
    _trace_hook = func

# Synchronization classes

Lock = _allocate_lock

def RLock(*args, **kwargs):
    return _RLock(*args, **kwargs)

class _RLock(_Verbose):

    def __init__(self, verbose=None):
        _Verbose.__init__(self, verbose)
        self.__block = _allocate_lock()
        self.__owner = None
        self.__count = 0

    def __repr__(self):
        owner = self.__owner
        return "<%s(%s, %d)>" % (
                self.__class__.__name__,
                owner and owner.name,
                self.__count)

    def acquire(self, blocking=1):
        me = current_thread()
        if self.__owner is me:
            self.__count = self.__count + 1
            if __debug__:
                self._note("%s.acquire(%s): recursive success", self, blocking)
            return 1
        rc = self.__block.acquire(blocking)
        if rc:
            self.__owner = me
            self.__count = 1
            if __debug__:
                self._note("%s.acquire(%s): initial success", self, blocking)
        else:
            if __debug__:
                self._note("%s.acquire(%s): failure", self, blocking)
        return rc

    __enter__ = acquire

    def release(self):
        if self.__owner is not current_thread():
            raise RuntimeError("cannot release un-aquired lock")
        self.__count = count = self.__count - 1
        if not count:
            self.__owner = None
            self.__block.release()
            if __debug__:
                self._note("%s.release(): final release", self)
        else:
            if __debug__:
                self._note("%s.release(): non-final release", self)

    def __exit__(self, t, v, tb):
        self.release()

    # Internal methods used by condition variables

    def _acquire_restore(self, count_owner):
        count, owner = count_owner
        self.__block.acquire()
        self.__count = count
        self.__owner = owner
        if __debug__:
            self._note("%s._acquire_restore()", self)

    def _release_save(self):
        if __debug__:
            self._note("%s._release_save()", self)
        count = self.__count
        self.__count = 0
        owner = self.__owner
        self.__owner = None
        self.__block.release()
        return (count, owner)

    def _is_owned(self):
        return self.__owner is current_thread()


def Condition(*args, **kwargs):
    return _Condition(*args, **kwargs)

class _Condition(_Verbose):

    def __init__(self, lock=None, verbose=None):
        _Verbose.__init__(self, verbose)
        if lock is None:
            lock = RLock()
        self.__lock = lock
        # Export the lock's acquire() and release() methods
        self.acquire = lock.acquire
        self.release = lock.release
        # If the lock defines _release_save() and/or _acquire_restore(),
        # these override the default implementations (which just call
        # release() and acquire() on the lock).  Ditto for _is_owned().
        try:
            self._release_save = lock._release_save
        except AttributeError:
            pass
        try:
            self._acquire_restore = lock._acquire_restore
        except AttributeError:
            pass
        try:
            self._is_owned = lock._is_owned
        except AttributeError:
            pass
        self.__waiters = []

    def __enter__(self):
        return self.__lock.__enter__()

    def __exit__(self, *args):
        return self.__lock.__exit__(*args)

    def __repr__(self):
        return "<Condition(%s, %d)>" % (self.__lock, len(self.__waiters))

    def _release_save(self):
        self.__lock.release()           # No state to save

    def _acquire_restore(self, x):
        self.__lock.acquire()           # Ignore saved state

    def _is_owned(self):
        # Return True if lock is owned by current_thread.
        # This method is called only if __lock doesn't have _is_owned().
        if self.__lock.acquire(0):
            self.__lock.release()
            return False
        else:
            return True

    def wait(self, timeout=None):
        if not self._is_owned():
            raise RuntimeError("cannot wait on un-aquired lock")
        waiter = _allocate_lock()
        waiter.acquire()
        self.__waiters.append(waiter)
        saved_state = self._release_save()
        try:    # restore state no matter what (e.g., KeyboardInterrupt)
            if timeout is None:
                waiter.acquire()
                if __debug__:
                    self._note("%s.wait(): got it", self)
            else:
                # Balancing act:  We can't afford a pure busy loop, so we
                # have to sleep; but if we sleep the whole timeout time,
                # we'll be unresponsive.  The scheme here sleeps very
                # little at first, longer as time goes on, but never longer
                # than 20 times per second (or the timeout time remaining).
                endtime = _time() + timeout
                delay = 0.0005 # 500 us -> initial delay of 1 ms
                while True:
                    gotit = waiter.acquire(0)
                    if gotit:
                        break
                    remaining = endtime - _time()
                    if remaining <= 0:
                        break
                    delay = min(delay * 2, remaining, .05)
                    _sleep(delay)
                if not gotit:
                    if __debug__:
                        self._note("%s.wait(%s): timed out", self, timeout)
                    try:
                        self.__waiters.remove(waiter)
                    except ValueError:
                        pass
                else:
                    if __debug__:
                        self._note("%s.wait(%s): got it", self, timeout)
        finally:
            self._acquire_restore(saved_state)

    def notify(self, n=1):
        if not self._is_owned():
            raise RuntimeError("cannot notify on un-aquired lock")
        __waiters = self.__waiters
        waiters = __waiters[:n]
        if not waiters:
            if __debug__:
                self._note("%s.notify(): no waiters", self)
            return
        self._note("%s.notify(): notifying %d waiter%s", self, n,
                   n!=1 and "s" or "")
        for waiter in waiters:
            waiter.release()
            try:
                __waiters.remove(waiter)
            except ValueError:
                pass

    def notifyAll(self):
        self.notify(len(self.__waiters))

    notify_all = notifyAll


def Semaphore(*args, **kwargs):
    return _Semaphore(*args, **kwargs)

class _Semaphore(_Verbose):

    # After Tim Peters' semaphore class, but not quite the same (no maximum)

    def __init__(self, value=1, verbose=None):
        if value < 0:
            raise ValueError("semaphore initial value must be >= 0")
        _Verbose.__init__(self, verbose)
        self.__cond = Condition(Lock())
        self.__value = value

    def acquire(self, blocking=1):
        rc = False
        self.__cond.acquire()
        while self.__value == 0:
            if not blocking:
                break
            if __debug__:
                self._note("%s.acquire(%s): blocked waiting, value=%s",
                           self, blocking, self.__value)
            self.__cond.wait()
        else:
            self.__value = self.__value - 1
            if __debug__:
                self._note("%s.acquire: success, value=%s",
                           self, self.__value)
            rc = True
        self.__cond.release()
        return rc

    __enter__ = acquire

    def release(self):
        self.__cond.acquire()
        self.__value = self.__value + 1
        if __debug__:
            self._note("%s.release: success, value=%s",
                       self, self.__value)
        self.__cond.notify()
        self.__cond.release()

    def __exit__(self, t, v, tb):
        self.release()


def BoundedSemaphore(*args, **kwargs):
    return _BoundedSemaphore(*args, **kwargs)

class _BoundedSemaphore(_Semaphore):
    """Semaphore that checks that # releases is <= # acquires"""
    def __init__(self, value=1, verbose=None):
        _Semaphore.__init__(self, value, verbose)
        self._initial_value = value

    def release(self):
        if self._Semaphore__value >= self._initial_value:
            raise ValueError, "Semaphore released too many times"
        return _Semaphore.release(self)


def Event(*args, **kwargs):
    return _Event(*args, **kwargs)

class _Event(_Verbose):

    # 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 isSet(self):
        return self.__flag

    is_set = isSet

    def set(self):
        self.__cond.acquire()
        try:
            self.__flag = True
            self.__cond.notify_all()
        finally:
            self.__cond.release()

    def clear(self):
        self.__cond.acquire()
        try:
            self.__flag = False
        finally:
            self.__cond.release()

    def wait(self, timeout=None):
        self.__cond.acquire()
        try:
            if not self.__flag:
                self.__cond.wait(timeout)
        finally:
            self.__cond.release()

# Helper to generate new thread names
_counter = 0
def _newname(template="Thread-%d"):
    global _counter
    _counter = _counter + 1
    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):

    __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):
        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 _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):
        if not self.__initialized:
            raise RuntimeError("thread.__init__() not called")
        if self.__started.is_set():
            raise RuntimeError("thread already started")
        if __debug__:
            self._note("%s.start(): starting thread", self)
        _active_limbo_lock.acquire()
        _limbo[self] = self
        _active_limbo_lock.release()
        _start_new_thread(self.__bootstrap, ())
        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()
            _active_limbo_lock.acquire()
            _active[self.__ident] = self
            del _limbo[self]
            _active_limbo_lock.release()
            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:
                    _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>>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):
        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")

        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):
        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 isAlive(self):
        assert self.__initialized, "Thread.__init__() not called"
        return self.__started.is_set() and not self.__stopped

    is_alive = isAlive

    @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

def Timer(*args, **kwargs):
    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")
        self._Thread__started.set()
        self._set_ident()
        _active_limbo_lock.acquire()
        _active[_get_ident()] = self
        _active_limbo_lock.release()

    def _set_daemon(self):
        return False

    def _exitfunc(self):
        self._Thread__stop()
        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)
        self._Thread__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"))

        # 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()
        _active_limbo_lock.acquire()
        _active[_get_ident()] = self
        _active_limbo_lock.release()

    def _set_daemon(self):
        return True

    def join(self, timeout=None):
        assert False, "cannot join a dummy thread"


# Global API functions

def currentThread():
    try:
        return _active[_get_ident()]
    except KeyError:
        ##print "current_thread(): no current thread for", _get_ident()
        return _DummyThread()

current_thread = currentThread

def activeCount():
    _active_limbo_lock.acquire()
    count = len(_active) + len(_limbo)
    _active_limbo_lock.release()
    return count

active_count = activeCount

def enumerate():
    _active_limbo_lock.acquire()
    active = _active.values() + _limbo.values()
    _active_limbo_lock.release()
    return active

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.itervalues():
            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.
                # We don't call _Thread__stop() because it tries to acquire
                # thread._Thread__block which could also have been held while
                # we forked.
                thread._Thread__stopped = True

        _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()
Tip: Filter by directory path e.g. /media app.js to search for public/media/app.js.
Tip: Use camelCasing e.g. ProjME to search for ProjectModifiedEvent.java.
Tip: Filter by extension type e.g. /repo .js to search for all .js files in the /repo directory.
Tip: Separate your search with spaces e.g. /ssh pom.xml to search for src/ssh/pom.xml.
Tip: Use ↑ and ↓ arrow keys to navigate and return to view the file.
Tip: You can also navigate files with Ctrl+j (next) and Ctrl+k (previous) and view the file with Ctrl+o.
Tip: You can also navigate files with Alt+j (next) and Alt+k (previous) and view the file with Alt+o.