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+
+:mod:`mutex` --- Mutual exclusion support
+=========================================
+
+.. module:: mutex
+   :synopsis: Lock and queue for mutual exclusion.
+.. sectionauthor:: Moshe Zadka <moshez@zadka.site.co.il>
+
+
+The :mod:`mutex` module defines a class that allows mutual-exclusion via
+acquiring and releasing locks. It does not require (or imply) threading or
+multi-tasking, though it could be useful for those purposes.
+
+The :mod:`mutex` module defines the following class:
+
+
+.. class:: mutex()
+
+   Create a new (unlocked) mutex.
+
+   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 zero 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
+   :meth:`lock`, where a function is called once the lock is acquired.
+
+
+.. _mutex-objects:
+
+Mutex Objects
+-------------
+
+:class:`mutex` objects have following methods:
+
+
+.. method:: mutex.test()
+
+   Check whether the mutex is locked.
+
+
+.. method:: mutex.testandset()
+
+   "Atomic" test-and-set, grab the lock if it is not set, and return ``True``,
+   otherwise, return ``False``.
+
+
+.. method:: mutex.lock(function, argument)
+
+   Execute ``function(argument)``, unless the mutex is locked. In the case it is
+   locked, place the function and argument on the queue. See :meth:`unlock` for
+   explanation of when ``function(argument)`` is executed in that case.
+
+
+.. method:: mutex.unlock()
+
+   Unlock the mutex if queue is empty, otherwise execute the first element in the
+   queue.
+