On Wed, Oct 24, 2012 at 2:19 PM, Ian Kelly <ian.g.ke...@gmail.com> wrote:
> I used a PriorityQueue and Conditions to get rid of the ugly while True loop.
Same things, but with Events instead of Conditions. This is just a
bit more readable.
The PriorityQueue is also probably unnecessary, since it's always
accessed with the mutex held. A heapq would be fine.
import threading
import Queue
class PriorityLock(object):
def __init__(self):
self._is_available = True
self._mutex = threading.Lock()
self._waiter_queue = Queue.PriorityQueue()
def acquire(self, priority=0):
self._mutex.acquire()
# First, just check the lock.
if self._is_available:
self._is_available = False
self._mutex.release()
return True
event = threading.Event()
self._waiter_queue.put((priority, event))
self._mutex.release()
event.wait()
# When the event is triggered, we have the lock.
return True
def release(self):
self._mutex.acquire()
# Notify the next thread in line, if any.
try:
_, event = self._waiter_queue.get_nowait()
except Queue.Empty:
self._is_available = True
else:
event.set()
self._mutex.release()
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