mirror of https://github.com/python/cpython
Remove the mutex module.
This commit is contained in:
parent
39143f8156
commit
d7cce26f7c
|
@ -26,7 +26,6 @@ The following modules are documented in this chapter:
|
||||||
bisect.rst
|
bisect.rst
|
||||||
array.rst
|
array.rst
|
||||||
sched.rst
|
sched.rst
|
||||||
mutex.rst
|
|
||||||
queue.rst
|
queue.rst
|
||||||
weakref.rst
|
weakref.rst
|
||||||
types.rst
|
types.rst
|
||||||
|
|
|
@ -1,63 +0,0 @@
|
||||||
|
|
||||||
: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)
|
|
||||||
:mod:`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.
|
|
||||||
|
|
|
@ -8,7 +8,7 @@
|
||||||
|
|
||||||
This module constructs higher-level threading interfaces on top of the lower
|
This module constructs higher-level threading interfaces on top of the lower
|
||||||
level :mod:`thread` module.
|
level :mod:`thread` module.
|
||||||
See also the :mod:`mutex` and :mod:`Queue` modules.
|
See also the :mod:`Queue` module.
|
||||||
|
|
||||||
The :mod:`dummy_threading` module is provided for situations where
|
The :mod:`dummy_threading` module is provided for situations where
|
||||||
:mod:`threading` cannot be used because :mod:`thread` is missing.
|
:mod:`threading` cannot be used because :mod:`thread` is missing.
|
||||||
|
|
52
Lib/mutex.py
52
Lib/mutex.py
|
@ -1,52 +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 collections import deque
|
|
||||||
|
|
||||||
class mutex:
|
|
||||||
def __init__(self):
|
|
||||||
"""Create a new mutex -- initially unlocked."""
|
|
||||||
self.locked = 0
|
|
||||||
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 = 1
|
|
||||||
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 = 0
|
|
|
@ -1,33 +0,0 @@
|
||||||
import mutex
|
|
||||||
|
|
||||||
import unittest
|
|
||||||
import test.test_support
|
|
||||||
|
|
||||||
class MutexTest(unittest.TestCase):
|
|
||||||
|
|
||||||
def setUp(self):
|
|
||||||
self.mutex = mutex.mutex()
|
|
||||||
|
|
||||||
def called_by_mutex(self, some_data):
|
|
||||||
self.assert_(self.mutex.test(), "mutex not held")
|
|
||||||
# Nested locking
|
|
||||||
self.mutex.lock(self.called_by_mutex2, "eggs")
|
|
||||||
|
|
||||||
def called_by_mutex2(self, some_data):
|
|
||||||
self.assert_(self.ready_for_2,
|
|
||||||
"called_by_mutex2 called too soon")
|
|
||||||
|
|
||||||
def test_lock_and_unlock(self):
|
|
||||||
self.read_for_2 = False
|
|
||||||
self.mutex.lock(self.called_by_mutex, "spam")
|
|
||||||
self.ready_for_2 = True
|
|
||||||
# unlock both locks
|
|
||||||
self.mutex.unlock()
|
|
||||||
self.mutex.unlock()
|
|
||||||
self.failIf(self.mutex.test(), "mutex still held")
|
|
||||||
|
|
||||||
def test_main():
|
|
||||||
test.test_support.run_unittest(MutexTest)
|
|
||||||
|
|
||||||
if __name__ == "__main__":
|
|
||||||
test_main()
|
|
Loading…
Reference in New Issue