[Python-checkins] r70405 - python/trunk/Lib/Queue.py
georg.brandl
python-checkins at python.org
Sun Mar 15 23:11:07 CET 2009
Author: georg.brandl
Date: Sun Mar 15 23:11:07 2009
New Revision: 70405
Log:
Move the previously local import of threading to module level.
This is cleaner and avoids lockups in obscure cases where a Queue
is instantiated while the import lock is already held by another thread.
OKed by Tim Peters.
Modified:
python/trunk/Lib/Queue.py
Modified: python/trunk/Lib/Queue.py
==============================================================================
--- python/trunk/Lib/Queue.py (original)
+++ python/trunk/Lib/Queue.py Sun Mar 15 23:11:07 2009
@@ -1,6 +1,10 @@
"""A multi-producer, multi-consumer queue."""
from time import time as _time
+try:
+ import threading as _threading
+except ImportError:
+ import dummy_threading as _threading
from collections import deque
import heapq
@@ -20,26 +24,22 @@
If maxsize is <= 0, the queue size is infinite.
"""
def __init__(self, maxsize=0):
- try:
- import threading
- except ImportError:
- import dummy_threading as threading
self.maxsize = maxsize
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 three conditions, so acquiring and
# releasing the conditions also acquires and releases mutex.
- self.mutex = threading.Lock()
+ self.mutex = _threading.Lock()
# 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)
+ 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)
+ self.not_full = _threading.Condition(self.mutex)
# Notify all_tasks_done whenever the number of unfinished tasks
# drops to zero; thread waiting to join() is notified to resume
- self.all_tasks_done = threading.Condition(self.mutex)
+ self.all_tasks_done = _threading.Condition(self.mutex)
self.unfinished_tasks = 0
def task_done(self):
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