Mutex.cpp

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/*
 * Mutex.cpp
 *
 * Copyright (C) 2011 IBR, TU Braunschweig
 *
 * Written-by: Johannes Morgenroth <morgenroth@ibr.cs.tu-bs.de>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

#include "ibrcommon/config.h"
#include "ibrcommon/thread/Mutex.h"
#include <errno.h>

namespace ibrcommon
{
        MutexInterface::~MutexInterface()
        {
        }

        Mutex::Mutex(MUTEX_TYPE type)
        {
                pthread_mutexattr_init(&m_attr);
                pthread_mutexattr_settype(&m_attr, type);
                pthread_mutex_init(&m_mutex, &m_attr);
        }

        Mutex::~Mutex()
        {
                pthread_mutex_destroy( &m_mutex );
                pthread_mutexattr_destroy(&m_attr);
        }

        void Mutex::trylock() throw (MutexException)
        {
                int ret = pthread_mutex_trylock( &m_mutex );

                switch (ret)
                {
                case 0:
                        break;

                case EBUSY:
                        throw MutexException("The mutex could not be acquired because it was already locked.");
                        break;
                }
        }

        void Mutex::enter() throw (MutexException)
        {
                switch (pthread_mutex_lock( &m_mutex ))
                {
                case 0:
                        return;

//              case EINVAL:
//                      throw MutexException("The mutex was created with the protocol attribute having the value PTHREAD_PRIO_PROTECT and the calling thread's priority is higher than the mutex's current priority ceiling.");

                // The pthread_mutex_trylock() function will fail if:

                case EBUSY:
                        throw MutexException("The mutex could not be acquired because it was already locked.");

                // The pthread_mutex_lock(), pthread_mutex_trylock() and pthread_mutex_unlock() functions may fail if:

                case EINVAL:
                        throw MutexException("The value specified by mutex does not refer to an initialised mutex object.");

                case EAGAIN:
                        throw MutexException("The mutex could not be acquired because the maximum number of recursive locks for mutex has been exceeded.");

                // The pthread_mutex_lock() function may fail if:

                case EDEADLK:
                        throw MutexException("The current thread already owns the mutex.");

                // The pthread_mutex_unlock() function may fail if:

                case EPERM:
                        throw MutexException("The current thread does not own the mutex.");

                default:
                        throw MutexException("can not lock the mutex");
                }
        }

        void Mutex::leave() throw (MutexException)
        {
                if (0 != pthread_mutex_unlock( &m_mutex ))
                {
                        throw MutexException("can not unlock mutex");
                }
        }

        MutexMock Mutex::_dummy;

        MutexInterface& Mutex::dummy()
        {
                return _dummy;
        }
}