77 lines
1.8 KiB
C++
77 lines
1.8 KiB
C++
/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2003 Robert Osfield
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*
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* This library is open source and may be redistributed and/or modified under
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* the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
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* (at your option) any later version. The full license is in LICENSE file
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* included with this distribution, and on the openscenegraph.org website.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* OpenSceneGraph Public License for more details.
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*/
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#include <osgDB/ReentrantMutex>
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using namespace osgDB;
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using namespace OpenThreads;
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ReentrantMutex::ReentrantMutex():
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_threadHoldingMutex(0),
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_lockCount(0)
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{
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}
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ReentrantMutex::~ReentrantMutex()
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{
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}
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int ReentrantMutex::lock()
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{
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if (_threadHoldingMutex==OpenThreads::Thread::CurrentThread() && _lockCount>0)
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{
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++_lockCount;
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return 0;
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}
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else
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{
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int result = Mutex::lock();
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if (result==0)
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{
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_threadHoldingMutex = OpenThreads::Thread::CurrentThread();
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_lockCount = 1;
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}
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return result;
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}
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}
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int ReentrantMutex::unlock()
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{
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if (_threadHoldingMutex==OpenThreads::Thread::CurrentThread() && _lockCount>0)
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{
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--_lockCount;
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if (_lockCount<=0) return Mutex::unlock();
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}
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return 0;
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}
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int ReentrantMutex::trylock()
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{
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if (_threadHoldingMutex==OpenThreads::Thread::CurrentThread() && _lockCount>0)
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{
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++_lockCount;
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return 0;
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}
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else
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{
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int result = Mutex::trylock();
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if (result==0)
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{
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_threadHoldingMutex = OpenThreads::Thread::CurrentThread();
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_lockCount = 1;
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}
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return result;
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}
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}
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