cpython-lru_cache-weakref: Lib/Queue.py annotate

annotate Lib/Queue.py @ 33091:48100a01ac7c 2.3

Ignore the locale's encoding if it is an empty string.

author	Martin v. Löwis <martin@v.loewis.de>
date	Thu, 12 Aug 2004 13:14:20 +0000
parents	58132c813d7b
children	63fa60f2d61c

rev	line source
11691 e34991022571 Mass patch by Ka-Ping Yee: Guido van Rossum <guido@python.org> parents: 11267 diff changeset	1 """A multi-producer, multi-consumer queue."""
995 f025eef93130 New module implementing a multi-everything queue. Guido van Rossum <guido@python.org> parents: diff changeset	2
25796 3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	3 from time import time as _time, sleep as _sleep
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	4
29711 58132c813d7b Add __all__ . Brett Cannon <bcannon@gmail.com> parents: 26892 diff changeset	5 __all__ = ['Empty', 'Full', 'Queue']
58132c813d7b Add __all__ . Brett Cannon <bcannon@gmail.com> parents: 26892 diff changeset	6
15902 eef321b6e41c Variant of Skip's patch 103246 (Remove unneeded string exception compat from Queue). Tim Peters <tim.peters@gmail.com> parents: 13050 diff changeset	7 class Empty(Exception):
eef321b6e41c Variant of Skip's patch 103246 (Remove unneeded string exception compat from Queue). Tim Peters <tim.peters@gmail.com> parents: 13050 diff changeset	8 "Exception raised by Queue.get(block=0)/get_nowait()."
eef321b6e41c Variant of Skip's patch 103246 (Remove unneeded string exception compat from Queue). Tim Peters <tim.peters@gmail.com> parents: 13050 diff changeset	9 pass
eef321b6e41c Variant of Skip's patch 103246 (Remove unneeded string exception compat from Queue). Tim Peters <tim.peters@gmail.com> parents: 13050 diff changeset	10
eef321b6e41c Variant of Skip's patch 103246 (Remove unneeded string exception compat from Queue). Tim Peters <tim.peters@gmail.com> parents: 13050 diff changeset	11 class Full(Exception):
eef321b6e41c Variant of Skip's patch 103246 (Remove unneeded string exception compat from Queue). Tim Peters <tim.peters@gmail.com> parents: 13050 diff changeset	12 "Exception raised by Queue.put(block=0)/put_nowait()."
eef321b6e41c Variant of Skip's patch 103246 (Remove unneeded string exception compat from Queue). Tim Peters <tim.peters@gmail.com> parents: 13050 diff changeset	13 pass
995 f025eef93130 New module implementing a multi-everything queue. Guido van Rossum <guido@python.org> parents: diff changeset	14
f025eef93130 New module implementing a multi-everything queue. Guido van Rossum <guido@python.org> parents: diff changeset	15 class Queue:
11267 2b26e48a85a6 Make the maxsize constructor argument default to 0 (an unlimited queue size). Guido van Rossum <guido@python.org> parents: 10120 diff changeset	16 def __init__(self, maxsize=0):
7755 fb4b4d069cc7 Mass check-in after untabifying all files that need it. Guido van Rossum <guido@python.org> parents: 6612 diff changeset	17 """Initialize a queue object with a given maximum size.
995 f025eef93130 New module implementing a multi-everything queue. Guido van Rossum <guido@python.org> parents: diff changeset	18
7755 fb4b4d069cc7 Mass check-in after untabifying all files that need it. Guido van Rossum <guido@python.org> parents: 6612 diff changeset	19 If maxsize is <= 0, the queue size is infinite.
fb4b4d069cc7 Mass check-in after untabifying all files that need it. Guido van Rossum <guido@python.org> parents: 6612 diff changeset	20 """
26892 95510f0a0624 Use the dummy_thread module in Queue.py and tempfile.py. Guido van Rossum <guido@python.org> parents: 25796 diff changeset	21 try:
95510f0a0624 Use the dummy_thread module in Queue.py and tempfile.py. Guido van Rossum <guido@python.org> parents: 25796 diff changeset	22 import thread
95510f0a0624 Use the dummy_thread module in Queue.py and tempfile.py. Guido van Rossum <guido@python.org> parents: 25796 diff changeset	23 except ImportError:
95510f0a0624 Use the dummy_thread module in Queue.py and tempfile.py. Guido van Rossum <guido@python.org> parents: 25796 diff changeset	24 import dummy_thread as thread
7755 fb4b4d069cc7 Mass check-in after untabifying all files that need it. Guido van Rossum <guido@python.org> parents: 6612 diff changeset	25 self._init(maxsize)
fb4b4d069cc7 Mass check-in after untabifying all files that need it. Guido van Rossum <guido@python.org> parents: 6612 diff changeset	26 self.mutex = thread.allocate_lock()
fb4b4d069cc7 Mass check-in after untabifying all files that need it. Guido van Rossum <guido@python.org> parents: 6612 diff changeset	27 self.esema = thread.allocate_lock()
8197 3a55b4c5e3c7 Replace all calls to acquire_lock() and release_lock() with acquire() Guido van Rossum <guido@python.org> parents: 7926 diff changeset	28 self.esema.acquire()
7755 fb4b4d069cc7 Mass check-in after untabifying all files that need it. Guido van Rossum <guido@python.org> parents: 6612 diff changeset	29 self.fsema = thread.allocate_lock()
995 f025eef93130 New module implementing a multi-everything queue. Guido van Rossum <guido@python.org> parents: diff changeset	30
6612 4b2d8dc92db4 (Queue.Empty): When class based exceptions are in force, derive this Barry Warsaw <barry@python.org> parents: 1463 diff changeset	31 def qsize(self):
10120 5b15642e7bdf Tim Peters: Guido van Rossum <guido@python.org> parents: 8197 diff changeset	32 """Return the approximate size of the queue (not reliable!)."""
8197 3a55b4c5e3c7 Replace all calls to acquire_lock() and release_lock() with acquire() Guido van Rossum <guido@python.org> parents: 7926 diff changeset	33 self.mutex.acquire()
7755 fb4b4d069cc7 Mass check-in after untabifying all files that need it. Guido van Rossum <guido@python.org> parents: 6612 diff changeset	34 n = self._qsize()
8197 3a55b4c5e3c7 Replace all calls to acquire_lock() and release_lock() with acquire() Guido van Rossum <guido@python.org> parents: 7926 diff changeset	35 self.mutex.release()
7755 fb4b4d069cc7 Mass check-in after untabifying all files that need it. Guido van Rossum <guido@python.org> parents: 6612 diff changeset	36 return n
995 f025eef93130 New module implementing a multi-everything queue. Guido van Rossum <guido@python.org> parents: diff changeset	37
6612 4b2d8dc92db4 (Queue.Empty): When class based exceptions are in force, derive this Barry Warsaw <barry@python.org> parents: 1463 diff changeset	38 def empty(self):
25796 3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	39 """Return True if the queue is empty, False otherwise (not reliable!)."""
8197 3a55b4c5e3c7 Replace all calls to acquire_lock() and release_lock() with acquire() Guido van Rossum <guido@python.org> parents: 7926 diff changeset	40 self.mutex.acquire()
7755 fb4b4d069cc7 Mass check-in after untabifying all files that need it. Guido van Rossum <guido@python.org> parents: 6612 diff changeset	41 n = self._empty()
8197 3a55b4c5e3c7 Replace all calls to acquire_lock() and release_lock() with acquire() Guido van Rossum <guido@python.org> parents: 7926 diff changeset	42 self.mutex.release()
7755 fb4b4d069cc7 Mass check-in after untabifying all files that need it. Guido van Rossum <guido@python.org> parents: 6612 diff changeset	43 return n
995 f025eef93130 New module implementing a multi-everything queue. Guido van Rossum <guido@python.org> parents: diff changeset	44
6612 4b2d8dc92db4 (Queue.Empty): When class based exceptions are in force, derive this Barry Warsaw <barry@python.org> parents: 1463 diff changeset	45 def full(self):
25796 3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	46 """Return True if the queue is full, False otherwise (not reliable!)."""
8197 3a55b4c5e3c7 Replace all calls to acquire_lock() and release_lock() with acquire() Guido van Rossum <guido@python.org> parents: 7926 diff changeset	47 self.mutex.acquire()
7755 fb4b4d069cc7 Mass check-in after untabifying all files that need it. Guido van Rossum <guido@python.org> parents: 6612 diff changeset	48 n = self._full()
8197 3a55b4c5e3c7 Replace all calls to acquire_lock() and release_lock() with acquire() Guido van Rossum <guido@python.org> parents: 7926 diff changeset	49 self.mutex.release()
7755 fb4b4d069cc7 Mass check-in after untabifying all files that need it. Guido van Rossum <guido@python.org> parents: 6612 diff changeset	50 return n
995 f025eef93130 New module implementing a multi-everything queue. Guido van Rossum <guido@python.org> parents: diff changeset	51
25796 3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	52 def put(self, item, block=True, timeout=None):
7926 e29d435ab142 Clarify that put blocks when the queue is full. Add some blank Guido van Rossum <guido@python.org> parents: 7755 diff changeset	53 """Put an item into the queue.
e29d435ab142 Clarify that put blocks when the queue is full. Add some blank Guido van Rossum <guido@python.org> parents: 7755 diff changeset	54
25796 3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	55 If optional args 'block' is true and 'timeout' is None (the default),
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	56 block if necessary until a free slot is available. If 'timeout' is
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	57 a positive number, it blocks at most 'timeout' seconds and raises
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	58 the Full exception if no free slot was available within that time.
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	59 Otherwise ('block' is false), put an item on the queue if a free slot
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	60 is immediately available, else raise the Full exception ('timeout'
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	61 is ignored in that case).
10120 5b15642e7bdf Tim Peters: Guido van Rossum <guido@python.org> parents: 8197 diff changeset	62 """
5b15642e7bdf Tim Peters: Guido van Rossum <guido@python.org> parents: 8197 diff changeset	63 if block:
25796 3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	64 if timeout is None:
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	65 # blocking, w/o timeout, i.e. forever
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	66 self.fsema.acquire()
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	67 elif timeout >= 0:
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	68 # waiting max. 'timeout' seconds.
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	69 # this code snipped is from threading.py: _Event.wait():
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	70 # Balancing act: We can't afford a pure busy loop, so we
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	71 # have to sleep; but if we sleep the whole timeout time,
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	72 # we'll be unresponsive. The scheme here sleeps very
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	73 # little at first, longer as time goes on, but never longer
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	74 # than 20 times per second (or the timeout time remaining).
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	75 delay = 0.0005 # 500 us -> initial delay of 1 ms
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	76 endtime = _time() + timeout
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	77 while True:
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	78 if self.fsema.acquire(0):
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	79 break
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	80 remaining = endtime - _time()
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	81 if remaining <= 0: #time is over and no slot was free
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	82 raise Full
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	83 delay = min(delay * 2, remaining, .05)
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	84 _sleep(delay) #reduce CPU usage by using a sleep
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	85 else:
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	86 raise ValueError("'timeout' must be a positive number")
10120 5b15642e7bdf Tim Peters: Guido van Rossum <guido@python.org> parents: 8197 diff changeset	87 elif not self.fsema.acquire(0):
5b15642e7bdf Tim Peters: Guido van Rossum <guido@python.org> parents: 8197 diff changeset	88 raise Full
8197 3a55b4c5e3c7 Replace all calls to acquire_lock() and release_lock() with acquire() Guido van Rossum <guido@python.org> parents: 7926 diff changeset	89 self.mutex.acquire()
23160 c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	90 release_fsema = True
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	91 try:
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	92 was_empty = self._empty()
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	93 self._put(item)
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	94 # If we fail before here, the empty state has
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	95 # not changed, so we can skip the release of esema
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	96 if was_empty:
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	97 self.esema.release()
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	98 # If we fail before here, the queue can not be full, so
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	99 # release_full_sema remains True
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	100 release_fsema = not self._full()
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	101 finally:
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	102 # Catching system level exceptions here (RecursionDepth,
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	103 # OutOfMemory, etc) - so do as little as possible in terms
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	104 # of Python calls.
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	105 if release_fsema:
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	106 self.fsema.release()
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	107 self.mutex.release()
995 f025eef93130 New module implementing a multi-everything queue. Guido van Rossum <guido@python.org> parents: diff changeset	108
10120 5b15642e7bdf Tim Peters: Guido van Rossum <guido@python.org> parents: 8197 diff changeset	109 def put_nowait(self, item):
5b15642e7bdf Tim Peters: Guido van Rossum <guido@python.org> parents: 8197 diff changeset	110 """Put an item into the queue without blocking.
5b15642e7bdf Tim Peters: Guido van Rossum <guido@python.org> parents: 8197 diff changeset	111
5b15642e7bdf Tim Peters: Guido van Rossum <guido@python.org> parents: 8197 diff changeset	112 Only enqueue the item if a free slot is immediately available.
5b15642e7bdf Tim Peters: Guido van Rossum <guido@python.org> parents: 8197 diff changeset	113 Otherwise raise the Full exception.
5b15642e7bdf Tim Peters: Guido van Rossum <guido@python.org> parents: 8197 diff changeset	114 """
25796 3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	115 return self.put(item, False)
7926 e29d435ab142 Clarify that put blocks when the queue is full. Add some blank Guido van Rossum <guido@python.org> parents: 7755 diff changeset	116
25796 3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	117 def get(self, block=True, timeout=None):
10120 5b15642e7bdf Tim Peters: Guido van Rossum <guido@python.org> parents: 8197 diff changeset	118 """Remove and return an item from the queue.
5b15642e7bdf Tim Peters: Guido van Rossum <guido@python.org> parents: 8197 diff changeset	119
25796 3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	120 If optional args 'block' is true and 'timeout' is None (the default),
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	121 block if necessary until an item is available. If 'timeout' is
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	122 a positive number, it blocks at most 'timeout' seconds and raises
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	123 the Empty exception if no item was available within that time.
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	124 Otherwise ('block' is false), return an item if one is immediately
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	125 available, else raise the Empty exception ('timeout' is ignored
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	126 in that case).
7755 fb4b4d069cc7 Mass check-in after untabifying all files that need it. Guido van Rossum <guido@python.org> parents: 6612 diff changeset	127 """
10120 5b15642e7bdf Tim Peters: Guido van Rossum <guido@python.org> parents: 8197 diff changeset	128 if block:
25796 3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	129 if timeout is None:
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	130 # blocking, w/o timeout, i.e. forever
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	131 self.esema.acquire()
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	132 elif timeout >= 0:
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	133 # waiting max. 'timeout' seconds.
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	134 # this code snipped is from threading.py: _Event.wait():
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	135 # Balancing act: We can't afford a pure busy loop, so we
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	136 # have to sleep; but if we sleep the whole timeout time,
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	137 # we'll be unresponsive. The scheme here sleeps very
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	138 # little at first, longer as time goes on, but never longer
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	139 # than 20 times per second (or the timeout time remaining).
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	140 delay = 0.0005 # 500 us -> initial delay of 1 ms
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	141 endtime = _time() + timeout
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	142 while 1:
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	143 if self.esema.acquire(0):
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	144 break
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	145 remaining = endtime - _time()
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	146 if remaining <= 0: #time is over and no element arrived
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	147 raise Empty
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	148 delay = min(delay * 2, remaining, .05)
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	149 _sleep(delay) #reduce CPU usage by using a sleep
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	150 else:
3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	151 raise ValueError("'timeout' must be a positive number")
10120 5b15642e7bdf Tim Peters: Guido van Rossum <guido@python.org> parents: 8197 diff changeset	152 elif not self.esema.acquire(0):
5b15642e7bdf Tim Peters: Guido van Rossum <guido@python.org> parents: 8197 diff changeset	153 raise Empty
8197 3a55b4c5e3c7 Replace all calls to acquire_lock() and release_lock() with acquire() Guido van Rossum <guido@python.org> parents: 7926 diff changeset	154 self.mutex.acquire()
23160 c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	155 release_esema = True
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	156 try:
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	157 was_full = self._full()
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	158 item = self._get()
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	159 # If we fail before here, the full state has
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	160 # not changed, so we can skip the release of fsema
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	161 if was_full:
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	162 self.fsema.release()
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	163 # Failure means empty state also unchanged - release_esema
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	164 # remains True.
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	165 release_esema = not self._empty()
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	166 finally:
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	167 if release_esema:
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	168 self.esema.release()
c548e726b3bc Fix bug 544473 - "Queue module can deadlock". Mark Hammond <mhammond@skippinet.com.au> parents: 16657 diff changeset	169 self.mutex.release()
7755 fb4b4d069cc7 Mass check-in after untabifying all files that need it. Guido van Rossum <guido@python.org> parents: 6612 diff changeset	170 return item
995 f025eef93130 New module implementing a multi-everything queue. Guido van Rossum <guido@python.org> parents: diff changeset	171
6612 4b2d8dc92db4 (Queue.Empty): When class based exceptions are in force, derive this Barry Warsaw <barry@python.org> parents: 1463 diff changeset	172 def get_nowait(self):
10120 5b15642e7bdf Tim Peters: Guido van Rossum <guido@python.org> parents: 8197 diff changeset	173 """Remove and return an item from the queue without blocking.
7926 e29d435ab142 Clarify that put blocks when the queue is full. Add some blank Guido van Rossum <guido@python.org> parents: 7755 diff changeset	174
25796 3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	175 Only get an item if one is immediately available. Otherwise
10120 5b15642e7bdf Tim Peters: Guido van Rossum <guido@python.org> parents: 8197 diff changeset	176 raise the Empty exception.
7755 fb4b4d069cc7 Mass check-in after untabifying all files that need it. Guido van Rossum <guido@python.org> parents: 6612 diff changeset	177 """
25796 3eafbde56b21 Patch #572628: Optional timeouts for put and get. Martin v. Löwis <martin@v.loewis.de> parents: 24058 diff changeset	178 return self.get(False)
6612 4b2d8dc92db4 (Queue.Empty): When class based exceptions are in force, derive this Barry Warsaw <barry@python.org> parents: 1463 diff changeset	179
4b2d8dc92db4 (Queue.Empty): When class based exceptions are in force, derive this Barry Warsaw <barry@python.org> parents: 1463 diff changeset	180 # Override these methods to implement other queue organizations
4b2d8dc92db4 (Queue.Empty): When class based exceptions are in force, derive this Barry Warsaw <barry@python.org> parents: 1463 diff changeset	181 # (e.g. stack or priority queue).
4b2d8dc92db4 (Queue.Empty): When class based exceptions are in force, derive this Barry Warsaw <barry@python.org> parents: 1463 diff changeset	182 # These will only be called with appropriate locks held
995 f025eef93130 New module implementing a multi-everything queue. Guido van Rossum <guido@python.org> parents: diff changeset	183
6612 4b2d8dc92db4 (Queue.Empty): When class based exceptions are in force, derive this Barry Warsaw <barry@python.org> parents: 1463 diff changeset	184 # Initialize the queue representation
4b2d8dc92db4 (Queue.Empty): When class based exceptions are in force, derive this Barry Warsaw <barry@python.org> parents: 1463 diff changeset	185 def _init(self, maxsize):
7755 fb4b4d069cc7 Mass check-in after untabifying all files that need it. Guido van Rossum <guido@python.org> parents: 6612 diff changeset	186 self.maxsize = maxsize
fb4b4d069cc7 Mass check-in after untabifying all files that need it. Guido van Rossum <guido@python.org> parents: 6612 diff changeset	187 self.queue = []
995 f025eef93130 New module implementing a multi-everything queue. Guido van Rossum <guido@python.org> parents: diff changeset	188
6612 4b2d8dc92db4 (Queue.Empty): When class based exceptions are in force, derive this Barry Warsaw <barry@python.org> parents: 1463 diff changeset	189 def _qsize(self):
7755 fb4b4d069cc7 Mass check-in after untabifying all files that need it. Guido van Rossum <guido@python.org> parents: 6612 diff changeset	190 return len(self.queue)
995 f025eef93130 New module implementing a multi-everything queue. Guido van Rossum <guido@python.org> parents: diff changeset	191
13050 a195962e389c typos fixed by Rob Hooft Jeremy Hylton <jeremy@alum.mit.edu> parents: 11691 diff changeset	192 # Check whether the queue is empty
6612 4b2d8dc92db4 (Queue.Empty): When class based exceptions are in force, derive this Barry Warsaw <barry@python.org> parents: 1463 diff changeset	193 def _empty(self):
7755 fb4b4d069cc7 Mass check-in after untabifying all files that need it. Guido van Rossum <guido@python.org> parents: 6612 diff changeset	194 return not self.queue
995 f025eef93130 New module implementing a multi-everything queue. Guido van Rossum <guido@python.org> parents: diff changeset	195
6612 4b2d8dc92db4 (Queue.Empty): When class based exceptions are in force, derive this Barry Warsaw <barry@python.org> parents: 1463 diff changeset	196 # Check whether the queue is full
4b2d8dc92db4 (Queue.Empty): When class based exceptions are in force, derive this Barry Warsaw <barry@python.org> parents: 1463 diff changeset	197 def _full(self):
7755 fb4b4d069cc7 Mass check-in after untabifying all files that need it. Guido van Rossum <guido@python.org> parents: 6612 diff changeset	198 return self.maxsize > 0 and len(self.queue) == self.maxsize
995 f025eef93130 New module implementing a multi-everything queue. Guido van Rossum <guido@python.org> parents: diff changeset	199
6612 4b2d8dc92db4 (Queue.Empty): When class based exceptions are in force, derive this Barry Warsaw <barry@python.org> parents: 1463 diff changeset	200 # Put a new item in the queue
4b2d8dc92db4 (Queue.Empty): When class based exceptions are in force, derive this Barry Warsaw <barry@python.org> parents: 1463 diff changeset	201 def _put(self, item):
7755 fb4b4d069cc7 Mass check-in after untabifying all files that need it. Guido van Rossum <guido@python.org> parents: 6612 diff changeset	202 self.queue.append(item)
995 f025eef93130 New module implementing a multi-everything queue. Guido van Rossum <guido@python.org> parents: diff changeset	203
6612 4b2d8dc92db4 (Queue.Empty): When class based exceptions are in force, derive this Barry Warsaw <barry@python.org> parents: 1463 diff changeset	204 # Get an item from the queue
4b2d8dc92db4 (Queue.Empty): When class based exceptions are in force, derive this Barry Warsaw <barry@python.org> parents: 1463 diff changeset	205 def _get(self):
24058 37ffce2d9c3c Code modernization. Replace v=s[i]; del s[i] with single lookup v=s.pop(i) Raymond Hettinger <python@rcn.com> parents: 23160 diff changeset	206 return self.queue.pop(0)

Mercurial > cpython-lru_cache-weakref

annotate Lib/Queue.py @ 33091:48100a01ac7c 2.3