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Diffstat (limited to 'lib/python2.7/site-packages/SQLAlchemy-0.7.0-py2.7-linux-x86_64.egg/sqlalchemy/util/queue.py')
| -rwxr-xr-x | lib/python2.7/site-packages/SQLAlchemy-0.7.0-py2.7-linux-x86_64.egg/sqlalchemy/util/queue.py | 191 |
1 files changed, 0 insertions, 191 deletions
diff --git a/lib/python2.7/site-packages/SQLAlchemy-0.7.0-py2.7-linux-x86_64.egg/sqlalchemy/util/queue.py b/lib/python2.7/site-packages/SQLAlchemy-0.7.0-py2.7-linux-x86_64.egg/sqlalchemy/util/queue.py deleted file mode 100755 index db717595..00000000 --- a/lib/python2.7/site-packages/SQLAlchemy-0.7.0-py2.7-linux-x86_64.egg/sqlalchemy/util/queue.py +++ /dev/null @@ -1,191 +0,0 @@ -# util/queue.py -# Copyright (C) 2005-2011 the SQLAlchemy authors and contributors <see AUTHORS file> -# -# This module is part of SQLAlchemy and is released under -# the MIT License: http://www.opensource.org/licenses/mit-license.php - -"""An adaptation of Py2.3/2.4's Queue module which supports reentrant -behavior, using RLock instead of Lock for its mutex object. - -This is to support the connection pool's usage of weakref callbacks to return -connections to the underlying Queue, which can in extremely -rare cases be invoked within the ``get()`` method of the Queue itself, -producing a ``put()`` inside the ``get()`` and therefore a reentrant -condition.""" - -from collections import deque -from time import time as _time -from sqlalchemy.util import threading - -__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. - """ - - self._init(maxsize) - # mutex must be held whenever the queue is mutating. All methods - # that acquire mutex must release it before returning. mutex - # is shared between the two conditions, so acquiring and - # releasing the conditions also acquires and releases mutex. - self.mutex = threading.RLock() - # Notify not_empty whenever an item is added to the queue; a - # thread waiting to get is notified then. - self.not_empty = threading.Condition(self.mutex) - # Notify not_full whenever an item is removed from the queue; - # a thread waiting to put is notified then. - self.not_full = threading.Condition(self.mutex) - - 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). - """ - - self.not_full.acquire() - try: - if not block: - if self._full(): - raise Full - elif timeout is None: - while self._full(): - self.not_full.wait() - else: - if timeout < 0: - raise ValueError("'timeout' must be a positive number") - endtime = _time() + timeout - while self._full(): - remaining = endtime - _time() - if remaining <= 0.0: - raise Full - self.not_full.wait(remaining) - self._put(item) - self.not_empty.notify() - finally: - self.not_full.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). - """ - - self.not_empty.acquire() - try: - if not block: - if self._empty(): - raise Empty - elif timeout is None: - while self._empty(): - self.not_empty.wait() - else: - if timeout < 0: - raise ValueError("'timeout' must be a positive number") - endtime = _time() + timeout - while self._empty(): - remaining = endtime - _time() - if remaining <= 0.0: - raise Empty - self.not_empty.wait(remaining) - item = self._get() - self.not_full.notify() - return item - finally: - self.not_empty.release() - - 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 = deque() - - 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.popleft() |