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Diffstat (limited to 'lib/python2.7/mutex.py')
-rw-r--r-- | lib/python2.7/mutex.py | 55 |
1 files changed, 0 insertions, 55 deletions
diff --git a/lib/python2.7/mutex.py b/lib/python2.7/mutex.py deleted file mode 100644 index f8acba4..0000000 --- a/lib/python2.7/mutex.py +++ /dev/null @@ -1,55 +0,0 @@ -"""Mutual exclusion -- for use with module sched - -A mutex has two pieces of state -- a 'locked' bit and a queue. -When the mutex is not locked, the queue is empty. -Otherwise, the queue contains 0 or more (function, argument) pairs -representing functions (or methods) waiting to acquire the lock. -When the mutex is unlocked while the queue is not empty, -the first queue entry is removed and its function(argument) pair called, -implying it now has the lock. - -Of course, no multi-threading is implied -- hence the funny interface -for lock, where a function is called once the lock is aquired. -""" -from warnings import warnpy3k -warnpy3k("the mutex module has been removed in Python 3.0", stacklevel=2) -del warnpy3k - -from collections import deque - -class mutex: - def __init__(self): - """Create a new mutex -- initially unlocked.""" - self.locked = False - self.queue = deque() - - def test(self): - """Test the locked bit of the mutex.""" - return self.locked - - def testandset(self): - """Atomic test-and-set -- grab the lock if it is not set, - return True if it succeeded.""" - if not self.locked: - self.locked = True - return True - else: - return False - - def lock(self, function, argument): - """Lock a mutex, call the function with supplied argument - when it is acquired. If the mutex is already locked, place - function and argument in the queue.""" - if self.testandset(): - function(argument) - else: - self.queue.append((function, argument)) - - def unlock(self): - """Unlock a mutex. If the queue is not empty, call the next - function with its argument.""" - if self.queue: - function, argument = self.queue.popleft() - function(argument) - else: - self.locked = False |