/* -*- 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 <string.h>

#include <signal.h>

#include "fatal-error.h"

#include "system-thread.h"

#include "log.h"

NS_LOG_COMPONENT_DEFINE ("SystemThread");

namespace ns3 {

//

// Private implementation class for the SystemThread class.  The deal is

// that we export the SystemThread class to the user.  The header just 

// declares a class and its members.  There is a forward declaration for

// a private implementation class there and a member declaration.  Thus

// there is no knowledge of the implementation in the exported header.

//

// We provide an implementation class for each operating system.  This is

// the Unix implementation of the SystemThread.

//

// In order to use the SystemThread, you will include "system-thread.h" and

// get the implementation by linking unix-system-thread.cc (if you are running

// a Posix system).

//

class SystemThreadImpl

{

public:

  SystemThreadImpl (Callback<void> callback);

  void Start (void);

  void Join (void);

  void Shutdown (void);

  bool Break (void);

private:

  static void *DoRun (void *arg);

  Callback<void> m_callback;

  pthread_t m_thread;

  bool m_break;

  void *    m_ret;

};

SystemThreadImpl::SystemThreadImpl (Callback<void> callback)

  : m_callback (callback)

{

  NS_LOG_FUNCTION_NOARGS ();

  // Make sure we have a SIGALRM handler which does not terminate

  // our process.

  struct sigaction act;

  act.sa_flags = 0;

  sigemptyset (&act.sa_mask);

  act.sa_handler = SIG_IGN;

  sigaction (SIGALRM, &act, 0);

}

  void

SystemThreadImpl::Start (void)

{

  NS_LOG_FUNCTION_NOARGS ();

  int rc = pthread_create (&m_thread, NULL, &SystemThreadImpl::DoRun,

    (void *)this);

  if (rc) 

    {

      NS_FATAL_ERROR ("pthread_create failed: " << rc << "=\"" << 

        strerror(rc) << "\".");

    }

}

  void 

SystemThreadImpl::Join (void)

{

  NS_LOG_FUNCTION_NOARGS ();

  void *thread_return;

  int rc = pthread_join (m_thread, &thread_return);

  if (rc) 

    {

      NS_FATAL_ERROR ("pthread_join failed: " << rc << "=\"" << 

        strerror(rc) << "\".");

    }

}

  void 

SystemThreadImpl::Shutdown (void)

{

  NS_LOG_FUNCTION_NOARGS ();

  m_break = true;

  // send a SIGALRM signal on the target thread to make sure that it

  // will unblock.

  pthread_kill (m_thread, SIGALRM);

}

  bool

SystemThreadImpl::Break (void)

{

  NS_LOG_FUNCTION_NOARGS ();

  return m_break;

}

  void *

SystemThreadImpl::DoRun (void *arg)

{

  NS_LOG_FUNCTION_NOARGS ();

  SystemThreadImpl *self = static_cast<SystemThreadImpl *> (arg);

  self->m_callback ();

  return 0;

}

//

// Remember that we just export the delcaration of the SystemThread class to

// the user.  There is no code to implement the SystemThread methods.  We

// have to do that here.  We just vector the calls to our implementation 

// class above.

//

SystemThread::SystemThread (Callback<void> callback) 

  : m_impl (new SystemThreadImpl (callback))

{

  NS_LOG_FUNCTION_NOARGS ();

}

SystemThread::~SystemThread() 

{

  NS_LOG_FUNCTION_NOARGS ();

  delete m_impl;

}

  void 

SystemThread::Start (void)

{

  NS_LOG_FUNCTION_NOARGS ();

  m_impl->Start ();

}

  void 

SystemThread::Join (void) 

{

  NS_LOG_FUNCTION_NOARGS ();

  m_impl->Join ();

}  

  void 

SystemThread::Shutdown (void) 

{

  NS_LOG_FUNCTION_NOARGS ();

  m_impl->Shutdown ();

}  

  bool 

SystemThread::Break (void) 

{

  NS_LOG_FUNCTION_NOARGS ();

  return m_impl->Break ();

}  

} // namespace ns3