323ce02f23
This change has been done to make it easier for OpenSceneGraph users to check out the svn via https without any conflicts introduced with a http externals.
159 lines
3.4 KiB
C++
159 lines
3.4 KiB
C++
/* -*-c++-*- OpenThreads library, Copyright (C) 2002 - 2007 The Open Thread Group
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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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#ifndef _WIN32VODITIONPRODUCER_CONDITION
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#define PRODUCER_CONDITION
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#ifdef WIN32
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#include "Mutex.h"
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namespace OpenThreads {
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class Win32ConditionImpl
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{
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public:
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/// number of waiters.
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long waiters_;
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Condition(long max = 0L)
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{
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waiters_ = 0;
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sema_ = CreateSemaphore(NULL,0,0x7fffffff,NULL);
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waiters_done_ = CreateEvent(NULL,FALSE,FALSE,NULL);
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}
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~Condition()
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{
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// CloseHandle(sema_);
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// CloseHandle(waiters_done_);
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}
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inline int broadcast ()
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{
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waiters_lock_.lock();
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int have_waiters = 0;
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if (waiters_ > 0)
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{
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// We are broadcasting, even if there is just one waiter...
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// Record the fact that we are broadcasting. This helps the
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// wait() method know how to optimize itself. Be sure to
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// set this with the <waiters_lock_> held.
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was_broadcast_ = 1;
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have_waiters = 1;
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}
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waiters_lock_.unlock();
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int result = 0;
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if (have_waiters)
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{
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// Wake up all the waiters.
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ReleaseSemaphore(sema_,waiters_,NULL);
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WaitForSingleObject(waiters_done_,INFINITE) ;
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// This is okay, even without the <waiters_lock_> held because
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// no other waiter threads can wake up to access it.
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was_broadcast_ = 0;
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}
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return result;
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}
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inline int wait (Mutex& external_mutex)
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{
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// Prevent race conditions on the <waiters_> count.
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waiters_lock_.lock();
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waiters_++;
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waiters_lock_.unlock();
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int result = 0;
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external_mutex.unlock();
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DWORD dwResult = WaitForSingleObject(sema_,INFINITE);
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if(dwResult != WAIT_OBJECT_0)
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result = (int)dwResult;
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// Reacquire lock to avoid race conditions on the <waiters_> count.
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waiters_lock_.lock();
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// We're ready to return, so there's one less waiter.
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waiters_--;
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int last_waiter = was_broadcast_ && waiters_ == 0;
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// Release the lock so that other collaborating threads can make
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// progress.
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waiters_lock_.unlock();
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if (result != -1 && last_waiter)
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SetEvent(waiters_done_);
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external_mutex.lock();
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return result;
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}
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protected:
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/// Serialize access to the waiters count.
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Mutex waiters_lock_;
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/// Queue up threads waiting for the condition to become signaled.
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HANDLE sema_;
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/**
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* An auto reset event used by the broadcast/signal thread to wait
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* for the waiting thread(s) to wake up and get a chance at the
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* semaphore.
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*/
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HANDLE waiters_done_;
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/// Keeps track of whether we were broadcasting or just signaling.
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size_t was_broadcast_;
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};
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#else
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#include <pthread.h>
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namespace Producer {
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class PR_EXPORT Condition
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{
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public:
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/// number of waiters.
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Condition(long max)
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{
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pthread_cond_init( &_cond, 0L );
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}
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~Condition()
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{
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}
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inline int broadcast ()
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{
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return pthread_cond_broadcast(&_cond);
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}
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inline int wait (Mutex& external_mutex)
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{
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return pthread_cond_wait(&_cond);
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}
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protected:
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pthread_cond_t _cond;
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};
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#endif
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}
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#endif |