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Diffstat (limited to 'net/py-kenosis/files/python2.3-Queue.py')
| -rw-r--r-- | net/py-kenosis/files/python2.3-Queue.py | 206 |
1 files changed, 0 insertions, 206 deletions
diff --git a/net/py-kenosis/files/python2.3-Queue.py b/net/py-kenosis/files/python2.3-Queue.py deleted file mode 100644 index 980aee619ddc..000000000000 --- a/net/py-kenosis/files/python2.3-Queue.py +++ /dev/null @@ -1,206 +0,0 @@ -"""A multi-producer, multi-consumer queue.""" - -from time import time as _time, sleep as _sleep - -__all__ = ['Empty', 'Full', 'Queue'] - -class Empty(Exception): - "Exception raised by Queue.get(block=0)/get_nowait()." - pass - -class Full(Exception): - "Exception raised by Queue.put(block=0)/put_nowait()." - pass - -class Queue: - def __init__(self, maxsize=0): - """Initialize a queue object with a given maximum size. - - If maxsize is <= 0, the queue size is infinite. - """ - try: - import thread - except ImportError: - import dummy_thread as thread - self._init(maxsize) - self.mutex = thread.allocate_lock() - self.esema = thread.allocate_lock() - self.esema.acquire() - self.fsema = thread.allocate_lock() - - def qsize(self): - """Return the approximate size of the queue (not reliable!).""" - self.mutex.acquire() - n = self._qsize() - self.mutex.release() - return n - - def empty(self): - """Return True if the queue is empty, False otherwise (not reliable!).""" - self.mutex.acquire() - n = self._empty() - self.mutex.release() - return n - - def full(self): - """Return True if the queue is full, False otherwise (not reliable!).""" - self.mutex.acquire() - n = self._full() - self.mutex.release() - return n - - def put(self, item, block=True, timeout=None): - """Put an item into the queue. - - If optional args 'block' is true and 'timeout' is None (the default), - block if necessary until a free slot is available. If 'timeout' is - a positive number, it blocks at most 'timeout' seconds and raises - the Full exception if no free slot was available within that time. - Otherwise ('block' is false), put an item on the queue if a free slot - is immediately available, else raise the Full exception ('timeout' - is ignored in that case). - """ - if block: - if timeout is None: - # blocking, w/o timeout, i.e. forever - self.fsema.acquire() - elif timeout >= 0: - # waiting max. 'timeout' seconds. - # this code snipped is from threading.py: _Event.wait(): - # 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). - delay = 0.0005 # 500 us -> initial delay of 1 ms - endtime = _time() + timeout - while True: - if self.fsema.acquire(0): - break - remaining = endtime - _time() - if remaining <= 0: #time is over and no slot was free - raise Full - delay = min(delay * 2, remaining, .05) - _sleep(delay) #reduce CPU usage by using a sleep - else: - raise ValueError("'timeout' must be a positive number") - elif not self.fsema.acquire(0): - raise Full - self.mutex.acquire() - release_fsema = True - try: - was_empty = self._empty() - self._put(item) - # If we fail before here, the empty state has - # not changed, so we can skip the release of esema - if was_empty: - self.esema.release() - # If we fail before here, the queue can not be full, so - # release_full_sema remains True - release_fsema = not self._full() - finally: - # Catching system level exceptions here (RecursionDepth, - # OutOfMemory, etc) - so do as little as possible in terms - # of Python calls. - if release_fsema: - self.fsema.release() - self.mutex.release() - - def put_nowait(self, item): - """Put an item into the queue without blocking. - - Only enqueue the item if a free slot is immediately available. - Otherwise raise the Full exception. - """ - return self.put(item, False) - - def get(self, block=True, timeout=None): - """Remove and return an item from the queue. - - If optional args 'block' is true and 'timeout' is None (the default), - block if necessary until an item is available. If 'timeout' is - a positive number, it blocks at most 'timeout' seconds and raises - the Empty exception if no item was available within that time. - Otherwise ('block' is false), return an item if one is immediately - available, else raise the Empty exception ('timeout' is ignored - in that case). - """ - if block: - if timeout is None: - # blocking, w/o timeout, i.e. forever - self.esema.acquire() - elif timeout >= 0: - # waiting max. 'timeout' seconds. - # this code snipped is from threading.py: _Event.wait(): - # 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). - delay = 0.0005 # 500 us -> initial delay of 1 ms - endtime = _time() + timeout - while 1: - if self.esema.acquire(0): - break - remaining = endtime - _time() - if remaining <= 0: #time is over and no element arrived - raise Empty - delay = min(delay * 2, remaining, .05) - _sleep(delay) #reduce CPU usage by using a sleep - else: - raise ValueError("'timeout' must be a positive number") - elif not self.esema.acquire(0): - raise Empty - self.mutex.acquire() - release_esema = True - try: - was_full = self._full() - item = self._get() - # If we fail before here, the full state has - # not changed, so we can skip the release of fsema - if was_full: - self.fsema.release() - # Failure means empty state also unchanged - release_esema - # remains True. - release_esema = not self._empty() - finally: - if release_esema: - self.esema.release() - self.mutex.release() - return item - - def get_nowait(self): - """Remove and return an item from the queue without blocking. - - Only get an item if one is immediately available. Otherwise - raise the Empty exception. - """ - return self.get(False) - - # Override these methods to implement other queue organizations - # (e.g. stack or priority queue). - # These will only be called with appropriate locks held - - # Initialize the queue representation - def _init(self, maxsize): - self.maxsize = maxsize - self.queue = [] - - def _qsize(self): - return len(self.queue) - - # Check whether the queue is empty - def _empty(self): - return not self.queue - - # Check whether the queue is full - def _full(self): - return self.maxsize > 0 and len(self.queue) == self.maxsize - - # Put a new item in the queue - def _put(self, item): - self.queue.append(item) - - # Get an item from the queue - def _get(self): - return self.queue.pop(0) |