// $Id: Barrier.cpp 92069 2010-09-28 11:38:59Z johnnyw $

#include "ace/Barrier.h"

#if defined (ACE_HAS_THREADS)

#if !defined (__ACE_INLINE__)
#include "ace/Barrier.inl"
#endif /* __ACE_INLINE__ */

#include "ace/Guard_T.h"
#include "ace/OS_NS_errno.h"

#if defined (ACE_HAS_DUMP)
#  include "ace/Log_Msg.h"
#endif /* ACE_HAS_DUMP */

ACE_BEGIN_VERSIONED_NAMESPACE_DECL

ACE_ALLOC_HOOK_DEFINE(ACE_Sub_Barrier)

void
ACE_Sub_Barrier::dump (void) const
{
#if defined (ACE_HAS_DUMP)
// ACE_TRACE ("ACE_Sub_Barrier::dump");

  ACE_DEBUG ((LM_DEBUG, ACE_BEGIN_DUMP, this));
  this->barrier_finished_.dump ();
  ACE_DEBUG ((LM_DEBUG, ACE_TEXT ("running_threads_ = %d\n"), this->running_threads_));
  ACE_DEBUG ((LM_DEBUG, ACE_END_DUMP));
#endif /* ACE_HAS_DUMP */
}

ACE_Sub_Barrier::ACE_Sub_Barrier (unsigned int count,
                                  ACE_Thread_Mutex &lock,
                                  const ACE_TCHAR *name,
                                  void *arg)
  : barrier_finished_ (lock, name, arg),
    running_threads_ (count)
{
// ACE_TRACE ("ACE_Sub_Barrier::ACE_Sub_Barrier");
}

ACE_ALLOC_HOOK_DEFINE(ACE_Barrier)

void
ACE_Barrier::dump (void) const
{
#if defined (ACE_HAS_DUMP)
// ACE_TRACE ("ACE_Barrier::dump");

  ACE_DEBUG ((LM_DEBUG, ACE_BEGIN_DUMP, this));
  this->lock_.dump ();
  ACE_DEBUG ((LM_DEBUG, ACE_TEXT ("current_generation_ = %d"), this->current_generation_));
  ACE_DEBUG ((LM_DEBUG, ACE_TEXT ("\ncount_ = %d"), this->count_));
  this->sub_barrier_1_.dump ();
  this->sub_barrier_2_.dump ();
  ACE_DEBUG ((LM_DEBUG, ACE_END_DUMP));
#endif /* ACE_HAS_DUMP */
}

ACE_Barrier::ACE_Barrier (unsigned int count,
                          const ACE_TCHAR *name,
                          void *arg)
  : lock_ (name, (ACE_mutexattr_t *) arg),
    current_generation_ (0),
    count_ (count),
    sub_barrier_1_ (count, lock_, name, arg),
    sub_barrier_2_ (count, lock_, name, arg)
{
  ACE_TRACE ("ACE_Barrier::ACE_Barrier");
  this->sub_barrier_[0] = &this->sub_barrier_1_;
  this->sub_barrier_[1] = &this->sub_barrier_2_;
}

int
ACE_Barrier::wait (void)
{
  ACE_TRACE ("ACE_Barrier::wait");
  ACE_GUARD_RETURN (ACE_Thread_Mutex, ace_mon, this->lock_, -1);

  ACE_Sub_Barrier *sbp =
    this->sub_barrier_[this->current_generation_];

  // Check for shutdown...
  if (sbp == 0)
    {
      errno = ESHUTDOWN;
      return -1;
    }

  int retval = 0;

  if (sbp->running_threads_ == 1)
    {
      // We're the last running thread, so swap generations and tell
      // all the threads waiting on the barrier to continue on their
      // way.
      sbp->running_threads_ = this->count_;
      // Swap generations.
      this->current_generation_ = 1 - this->current_generation_;
      sbp->barrier_finished_.broadcast ();
    }
  else
    {
      --sbp->running_threads_;

      // Block until all the other threads wait().
      while (sbp->running_threads_ != this->count_)
        sbp->barrier_finished_.wait ();

      // We're awake and the count has completed. See if it completed
      // because all threads hit the barrier, or because the barrier
      // was shut down.
      if (this->sub_barrier_[this->current_generation_] == 0)
        {
          errno = ESHUTDOWN;
          retval = -1;
        }
    }

  return retval;
}

int
ACE_Barrier::shutdown (void)
{
  ACE_TRACE ("ACE_Barrier::shutdown");
  ACE_GUARD_RETURN (ACE_Thread_Mutex, ace_mon, this->lock_, -1);

  ACE_Sub_Barrier *sbp =
    this->sub_barrier_[this->current_generation_];

  // Check for shutdown...
  if (sbp == 0)
    {
      errno = ESHUTDOWN;
      return -1;
    }

  // Flag the shutdown
  this->sub_barrier_[0] = 0;
  this->sub_barrier_[1] = 0;
  // Tell all the threads waiting on the barrier to continue on their way.
  sbp->running_threads_ = this->count_;
  sbp->barrier_finished_.broadcast ();

  return 0;
}

ACE_ALLOC_HOOK_DEFINE(ACE_Thread_Barrier)

ACE_Thread_Barrier::ACE_Thread_Barrier (unsigned int count,
                                        const ACE_TCHAR *name)
  : ACE_Barrier (count, name)
{
// ACE_TRACE ("ACE_Thread_Barrier::ACE_Thread_Barrier");
}

void
ACE_Thread_Barrier::dump (void) const
{
#if defined (ACE_HAS_DUMP)
// ACE_TRACE ("ACE_Thread_Barrier::dump");
  ACE_Barrier::dump ();
#endif /* ACE_HAS_DUMP */
}

ACE_END_VERSIONED_NAMESPACE_DECL

#endif /* ACE_HAS_THREADS */
