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annotate roundup/backends/locking.py @ 7908:608f140237c9

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Add comment about filehandled opened in acquire_lock. Opened lock file is closed by caller and not in release_lock. Not sure why but this confused me.
author John Rouillard <rouilj@ieee.org>
date Sat, 27 Apr 2024 23:24:05 -0400
parents 6e3e4f24c753
children
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509a101305da node ids are now generated from a lockable store - no more race conditions
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1 #! /usr/bin/env python
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2 # Copyright (c) 2002 ekit.com Inc (http://www.ekit-inc.com/)
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3 #
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4 # Permission is hereby granted, free of charge, to any person obtaining a copy
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5 # of this software and associated documentation files (the "Software"), to deal
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6 # in the Software without restriction, including without limitation the rights
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7 # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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8 # copies of the Software, and to permit persons to whom the Software is
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9 # furnished to do so, subject to the following conditions:
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10 #
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11 # The above copyright notice and this permission notice shall be included in
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12 # all copies or substantial portions of the Software.
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13 #
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14 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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15 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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16 # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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17 # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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18 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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19 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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20 # SOFTWARE.
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21
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22 '''This module provides a generic interface to acquire and release
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23 exclusive access to a file.
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24
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25 It should work on Unix and Windows.
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26 '''
2005
fc52d57c6c3e documentation cleanup
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27 __docformat__ = 'restructuredtext'
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28
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13b3155869e0 Beginnings of a big code cleanup / modernisation to make 2to3 happy
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29 from roundup.backends import portalocker
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30
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31 def acquire_lock(path, block=1):
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32 '''Acquire a lock for the given path
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608f140237c9 Add comment about filehandled opened in acquire_lock.
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33 File is closed in caller not by unlock.
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34 '''
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35 file = open(path, 'w')
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36 if block:
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37 portalocker.lock(file, portalocker.LOCK_EX)
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38 else:
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39 portalocker.lock(file, portalocker.LOCK_EX|portalocker.LOCK_NB)
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40 return file
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41
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42 def release_lock(file):
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43 '''Release our lock on the given path
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44 '''
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45 portalocker.unlock(file)
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