mutex.cpp

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/*
 The Real-Time eXperiment Interface (RTXI)
 Copyright (C) 2011 Georgia Institute of Technology, University of Utah, Weill Cornell Medical College

 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 This program 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 General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program. If not, see <http://www.gnu.org/licenses/>.

*/

#include <mutex.h>
#include <rt.h>

Mutex::Locker::Locker(Mutex *m):mutex(m)
{
 if (mutex)
 mutex->lock();
}

Mutex::Locker::~Locker(void)
{
 if (mutex)
 mutex->unlock();
}

Mutex::Mutex(Mutex::type_t type)
{
 pthread_mutexattr_t attr;
 pthread_mutexattr_init(&attr);

 switch (type)
 {
 case RECURSIVE:
 pthread_mutexattr_settype(&attr,PTHREAD_MUTEX_RECURSIVE_NP);
 break;
 default:
 pthread_mutexattr_settype(&attr,PTHREAD_MUTEX_FAST_NP);
 }

 pthread_mutex_init(&mutex,&attr);
 pthread_mutexattr_destroy(&attr);
}

Mutex::~Mutex(void)
{
 pthread_mutex_destroy(&mutex);
}

void Mutex::lock(void)
{
#ifdef DEBUG
 if (RT::OS::isRealtime())
 {
 ERROR_MSG("Detected unsafe lock attempt in RT thread\n");
 if (!tryLock())
 ERROR_MSG("Failed to obtain the lock\n");
 return;
 }
#endif // DEBUG

 pthread_mutex_lock(&mutex);
}

void Mutex::unlock(void)
{
 pthread_mutex_unlock(&mutex);
}

bool Mutex::tryLock(void)
{
 return pthread_mutex_trylock(&mutex) == 0;
}