/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */

/*

 * Copyright (c) 2008 INRIA

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation;

 *

 * 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, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 *

 * Author: Mathieu Lacage <mathieu.lacage.inria.fr>

 */

#include <pthread.h>

#include <cstring>

#include <cerrno> // for strerror

#include "fatal-error.h"

#include "system-mutex.h"

#include "log.h"

NS_LOG_COMPONENT_DEFINE ("SystemMutex");

namespace ns3 {

class SystemMutexPrivate {

public: 

  SystemMutexPrivate ();

  ~SystemMutexPrivate ();

  void Lock (void);

  void Unlock (void);

private:

  pthread_mutex_t m_mutex;

};

SystemMutexPrivate::SystemMutexPrivate ()

{

  NS_LOG_FUNCTION (this);

  pthread_mutexattr_t attr;

  pthread_mutexattr_init (&attr);

//

// Make this an error checking mutex.  This will check to see if the current

// thread already owns the mutex before trying to lock it.  Instead of 

// deadlocking it returns an error.  It will also check to make sure a thread

// has previously called pthread_mutex_lock when it calls pthread_mutex_unlock.

//

// Linux and OS X (at least) have, of course chosen different names for the 

// error checking flags just to make life difficult.

//

#if defined (PTHREAD_MUTEX_ERRORCHECK_NP)

  pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_ERRORCHECK_NP);

#else

  pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_ERRORCHECK);

#endif

  pthread_mutex_init (&m_mutex, &attr);

}

SystemMutexPrivate::~SystemMutexPrivate() 

{

  NS_LOG_FUNCTION (this);

  pthread_mutex_destroy (&m_mutex);

}

void

SystemMutexPrivate::Lock (void)

{

  NS_LOG_FUNCTION (this);

  int rc = pthread_mutex_lock (&m_mutex);

  if (rc != 0) 

    {

      NS_FATAL_ERROR ("SystemMutexPrivate::Lock()"

                      "pthread_mutex_lock failed: " << rc << " = \"" <<

                      std::strerror (rc) << "\"");

    }

}

void

SystemMutexPrivate::Unlock (void) 

{

  NS_LOG_FUNCTION (this);

  int rc = pthread_mutex_unlock (&m_mutex);

  if (rc != 0)

    {

      NS_FATAL_ERROR ("SystemMutexPrivate::Unlock()"

                      "pthread_mutex_unlock failed: " << rc << " = \"" <<

                      std::strerror (rc) << "\"");

    }

}

SystemMutex::SystemMutex() 

  : m_priv (new SystemMutexPrivate ())

{

  NS_LOG_FUNCTION (this);

}

SystemMutex::~SystemMutex() 

{

  NS_LOG_FUNCTION (this);

  delete m_priv;

}

void

SystemMutex::Lock ()

{

  NS_LOG_FUNCTION (this);

  m_priv->Lock ();

}

void

SystemMutex::Unlock ()

{

  NS_LOG_FUNCTION (this);

  m_priv->Unlock ();

}

CriticalSection::CriticalSection (SystemMutex &mutex)

  : m_mutex (mutex)

{

  NS_LOG_FUNCTION (this << &mutex);

  m_mutex.Lock ();

}

CriticalSection::~CriticalSection ()

{

  NS_LOG_FUNCTION (this);

  m_mutex.Unlock ();

}

} // namespace ns3