COSC_4P82_Assignment_1/lib/beagle-3.0.3/PACC/Threading/Mutex.cpp

134 lines
3.7 KiB
C++

/*
* Portable Agile C++ Classes (PACC)
* Copyright (C) 2001-2003 by Marc Parizeau
* http://manitou.gel.ulaval.ca/~parizeau/PACC
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Contact:
* Laboratoire de Vision et Systemes Numeriques
* Departement de genie electrique et de genie informatique
* Universite Laval, Quebec, Canada, G1K 7P4
* http://vision.gel.ulaval.ca
*
*/
/*!
* \file PACC/Threading/Mutex.cpp
* \brief Class methods for the portable mutual exclusion lock.
* \author Marc Parizeau, Laboratoire de vision et systèmes numériques, Université Laval
* $Revision: 1.5.2.1 $
* $Date: 2007/09/10 18:24:10 $
*/
#include "Threading/Mutex.hpp"
#ifdef WIN32
#include <windows.h>
typedef HANDLE pthread_mutex_t;
#else
#include <pthread.h>
#include <sys/errno.h>
#endif
using namespace PACC;
/*! \brief Allocate native structure and create mutex.
Any error raised a Threading:Exception.
*/
Threading::Mutex::Mutex(void)
{
pthread_mutex_t* lMutex = new pthread_mutex_t;
#ifdef WIN32
if((*lMutex = ::CreateMutex(0, 0, 0)) == 0)
#else
if(::pthread_mutex_init(lMutex, 0))
#endif
throw Exception(eOtherError, "Mutex::Mutex() can't create!");
mMutex = lMutex;
}
//! Destroy mutex and free allocated native structure.
Threading::Mutex::~Mutex(void)
{
pthread_mutex_t* lMutex = (pthread_mutex_t*) mMutex;
#ifdef WIN32
while(::CloseHandle(*lMutex) == 0)
#else
while(::pthread_mutex_destroy(lMutex) == EBUSY)
#endif
{
// wait for mutex to unlock
lock();
unlock();
}
delete lMutex;
mMutex = 0;
}
/*! \brief Lock the mutex.
A thread should never lock a mutex twice consecutively (without calling method Mutex::unlock). Any error will raise a Threading::Exception.
*/
void Threading::Mutex::lock(void) const
{
pthread_mutex_t* lMutex = (pthread_mutex_t*) mMutex;
#ifdef WIN32
if(::WaitForSingleObject(*lMutex, INFINITE) != WAIT_OBJECT_0)
#else
if(::pthread_mutex_lock(lMutex) != 0)
#endif
throw Exception(eWouldDeadLock, "Mutex::lock() can't lock!");
}
/*! \brief Try to lock the mutex without blocking.
Return's true if successful; false otherwise.
Any error will raise a Threading::Exception.
*/
bool Threading::Mutex::tryLock(void) const
{
pthread_mutex_t* lMutex = (pthread_mutex_t*) mMutex;
#ifdef WIN32
int lValue = ::WaitForSingleObject(*lMutex, 0);
if(lValue == WAIT_TIMEOUT) return false;
if(lValue != WAIT_OBJECT_0)
#else
int lValue = ::pthread_mutex_trylock(lMutex);
if(lValue == EBUSY) return false;
if(lValue != 0)
#endif
throw Exception(eOtherError, "Mutex::trylock() can't trylock!");
return true;
}
/*! \brief Unlock the mutex.
A thread should never unlock a mutex twice consecutively (without calling method Mutex::lock). Any error will raise a Threading::Exception.
*/
void Threading::Mutex::unlock(void) const
{
pthread_mutex_t* lMutex = (pthread_mutex_t*) mMutex;
#ifdef WIN32
if(::ReleaseMutex(*lMutex) == 0)
#else
if(::pthread_mutex_unlock(lMutex) != 0)
#endif
throw Exception(eMutexNotOwned, "Mutex::unlock() can't unlock!");
}