path: root/ACE/examples/Threads/barrier2.cpp

// $Id$

// This test program illustrates how the ACE task workers/barrier
// synchronization mechanisms work in conjunction with the ACE_Task
// and the ACE_Thread_Manager.  The manual flag not set simulates user
// input, if set input comes from stdin until RETURN only is entered
// which stops all workers via a message block of length 0. This is an
// alernative shutdown of workers compared to queue deactivate.  The
// delay_put flag simulates a delay between the shutdown puts. All
// should work with this flag disabled!  The BARRIER_TYPE is supposed
// to enable/disable barrier sync on each svc a worker has done.

#include "ace/OS_NS_string.h"
#include "ace/OS_NS_unistd.h"
#include "ace/OS_main.h"
#include "ace/Task.h"
#include "ace/Service_Config.h"

ACE_RCSID(Threads, barrier2, "$Id$")

#if defined (ACE_HAS_THREADS)

#include "ace/Null_Barrier.h"
#define BARRIER_TYPE ACE_Null_Barrier

template <class BARRIER>
class Worker_Task : public ACE_Task<ACE_MT_SYNCH>
{
public:
  Worker_Task (ACE_Thread_Manager *thr_mgr,
	       int n_threads,
	       int inp_serialize = 1);

  virtual int producer (void);
  // produce input for workers

  virtual int input (ACE_Message_Block *mb);
  // Fill one message block via a certain input strategy.

  virtual int output (ACE_Message_Block *mb);
  // Forward one message block via a certain output strategy to the
  // next task if any.

  virtual int service (ACE_Message_Block *mb, int iter);
  // Perform one message block dependant service.

private:
  virtual int put (ACE_Message_Block *mb, ACE_Time_Value *tv=0);

  virtual int svc (void);
  // Iterate <n_iterations> time printing off a message and "waiting"
  // for all other threads to complete this iteration.

  // = Not needed for this test.
  virtual int open (void *) { return 0; }
  virtual int close (u_long)
  {
    ACE_DEBUG ((LM_DEBUG,
                "(%t) in close of worker\n"));
    return 0;
  }

  int nt_;
  // Number of worker threads to run.

  int inp_serialize_;

  BARRIER barrier_;
};

template <class BARRIER>
Worker_Task<BARRIER>::Worker_Task (ACE_Thread_Manager *thr_mgr,
				   int n_threads,
				   int inp_serialize)
  : ACE_Task<ACE_MT_SYNCH> (thr_mgr),
    barrier_ (n_threads)
{
  nt_ = n_threads;

  // Create worker threads.
  inp_serialize_ = inp_serialize;

  // Use the task's message queue for serialization (default) or run
  // service in the context of the caller thread.

  if (nt_ > 0 && inp_serialize == 1)
    if (this->activate (THR_NEW_LWP, n_threads) == -1)
      ACE_ERROR ((LM_ERROR,
                  "%p\n",
                  "activate failed"));
}

// Simply enqueue the Message_Block into the end of the queue.

template <class BARRIER> int
Worker_Task<BARRIER>::put (ACE_Message_Block *mb,
                           ACE_Time_Value *tv)
{
  int result;

  if (this->inp_serialize_)
    result = this->putq (mb, tv);
  else
    {
      static int iter = 0;
      result = this->service (mb, iter++);

      if (this->output (mb) < 0)
	ACE_DEBUG ((LM_DEBUG,
                    "(%t) output not connected!\n"));

      mb->release ();
    }
  return result;
}

template <class BARRIER> int
Worker_Task<BARRIER>::service (ACE_Message_Block *mb,
                               int iter)
{
  size_t length = mb->length ();

  if (length > 0)
    {
      ACE_DEBUG ((LM_DEBUG,
                  "(%t) in iteration %d len=%d text got:\n",
                  iter,
                  length));
      ACE_OS::write (ACE_STDOUT,
                     mb->rd_ptr (),
                     length);
      ACE_DEBUG ((LM_DEBUG,
                  "\n"));
    }
  return 0;
}

// Iterate <n_iterations> time printing off a message and "waiting"
// for all other threads to complete this iteration.

template <class BARRIER> int
Worker_Task<BARRIER>::svc (void)
{
  // Note that the <ACE_Task::svc_run> method automatically adds us to
  // the Thread_Manager when the thread begins.

  // Keep looping, reading a message out of the queue, until we get a
  // message with a length == 0, which signals us to quit.

  for (int iter = 1; ;iter++)
    {
      ACE_Message_Block *mb = 0;

      int result = this->getq (mb);

      if (result == -1)
	{
	  ACE_ERROR ((LM_ERROR,
		      "(%t) in iteration %d\n",
                      "error waiting for message in iteration",
                      iter));
	  break;
	}

      size_t length = mb->length ();
      this->service (mb,iter);

      if (length == 0)
	{
	  ACE_DEBUG ((LM_DEBUG,
                      "(%t) in iteration %d got quit, exit!\n",
                      iter));
	  mb->release ();
	  break;
	}

      this->barrier_.wait ();
      this->output (mb);

      mb->release ();
    }

  // Note that the <ACE_Task::svc_run> method automatically removes us
  // from the Thread_Manager when the thread exits.

  return 0;
}

template <class BARRIER> int
Worker_Task<BARRIER>::producer (void)
{
  // Keep reading stdin, until we reach EOF.

  for (;;)
    {
      // Allocate a new message.
      ACE_Message_Block *mb;

      ACE_NEW_RETURN (mb,
                      ACE_Message_Block (BUFSIZ),
                      -1);

      if (this->input (mb) == -1)
	return -1;
    }

  ACE_NOTREACHED (return 0);
}

template <class BARRIER> int
Worker_Task<BARRIER>::output (ACE_Message_Block *mb)
{
  return this->put_next (mb);
}

template <class BARRIER> int
Worker_Task<BARRIER>::input (ACE_Message_Block *mb)
{
  ACE_Message_Block *mb1;

#if !defined (manual)
  static int l = 0;
  char str[] = "kalle";
  ACE_OS::strcpy (mb->rd_ptr (), str);

  size_t n = ACE_OS::strlen (str);

  if (l == 1000)
    n = 1;
  l++;

  if (l == 0 || (l % 100 == 0))
    ACE_OS::sleep (5);
  if (n <= 1)
#else
    ACE_DEBUG ((LM_DEBUG,
                "(%t) press chars and enter to put a new message into task queue ...\n"));
  n = ACE_OS::read (ACE_STDIN,
                    mb->rd_ptr (),
                    mb->size ());
  if (n <= 1)
#endif /* manual */
    {
      // Send a shutdown message to the waiting threads and exit.
      // cout << "\nvor loop, dump of task msg queue:\n" << endl;
      // this->msg_queue ()->dump ();

      for (int i = 0; i < nt_; i++)
	{
	  ACE_DEBUG ((LM_DEBUG,
                      "(%t) eof, sending block for thread=%d\n",
                      i + 1));

	  ACE_NEW_RETURN (mb1,
                          ACE_Message_Block (2),
                          -1);
	  mb1->length (0);

	  if (this->put (mb1) == -1)
	    ACE_ERROR ((LM_ERROR,
                        "(%t) %p\n",
                        "put"));
#if defined (delay_put)
          // this sleep helps to shutdown correctly -> was an error!
	  ACE_OS::sleep (1);
#endif /* delay_put */
	}
      return -1;
    }
  else
    {
      // Send a normal message to the waiting threads and continue
      // producing.
      mb->wr_ptr (n);

      if (this->put (mb) == -1)
	ACE_ERROR ((LM_ERROR,
                    "(%t) %p\n",
                    "put"));
    }
  return 0;
}

int
ACE_TMAIN (int argc, ACE_TCHAR *argv[])
{
  int n_threads = argc > 1 ? ACE_OS::atoi (argv[1]) : ACE_DEFAULT_THREADS;

  ACE_DEBUG ((LM_DEBUG,
              "(%t) worker threads running=%d\n",
              n_threads));

  Worker_Task<BARRIER_TYPE> worker_task (ACE_Thread_Manager::instance (),
                                         /* n_threads */ 0,
                                         0);
  worker_task.producer ();

  // Wait for all the threads to reach their exit point.
  ACE_DEBUG ((LM_DEBUG,
              "(%t) waiting with thread manager ...\n"));

  ACE_Thread_Manager::instance ()->wait ();

  ACE_DEBUG ((LM_DEBUG,
              "(%t) done correct!\n"));
  return 0;
}

#else
int
ACE_TMAIN (int, ACE_TCHAR *[])
{
  ACE_ERROR ((LM_ERROR, "threads not supported on this platform\n"));
  return 0;
}
#endif /* ACE_HAS_THREADS */