// Message_Queue.cpp
// $Id$

#if !defined (ACE_MESSAGE_QUEUE_C)
#define ACE_MESSAGE_QUEUE_C

#define ACE_BUILD_DLL
#include "ace/Message_Queue.h"

#if !defined (__ACE_INLINE__)
#include "ace/Message_Queue.i"
#endif /* __ACE_INLINE__ */

ACE_ALLOC_HOOK_DEFINE(ACE_Message_Queue)

template <ACE_SYNCH_DECL>
ACE_Message_Queue_Iterator<ACE_SYNCH_USE>::ACE_Message_Queue_Iterator (ACE_Message_Queue <ACE_SYNCH_USE> &q)
  : queue_ (q),
    curr_ (q.head_)
{
}

template <ACE_SYNCH_DECL> int 
ACE_Message_Queue_Iterator<ACE_SYNCH_USE>::next (ACE_Message_Block *&entry)
{
  ACE_Read_Guard<ACE_SYNCH_MUTEX_T> m (this->queue_.lock_);

  if (this->curr_ != 0)
    {
      entry = this->curr_;
      return 1;
    }
  else
    return 0;
}

template <ACE_SYNCH_DECL> int 
ACE_Message_Queue_Iterator<ACE_SYNCH_USE>::done (void) const
{
  ACE_Read_Guard<ACE_SYNCH_MUTEX_T> m (this->queue_.lock_);

  return this->curr_ == 0;
}

template <ACE_SYNCH_DECL> int
ACE_Message_Queue_Iterator<ACE_SYNCH_USE>::advance (void)
{
  ACE_Read_Guard<ACE_SYNCH_MUTEX_T> m (this->queue_.lock_);

  this->curr_ = this->curr_->next ();
  return this->curr_ != 0;
}

template <ACE_SYNCH_DECL> void 
ACE_Message_Queue_Iterator<ACE_SYNCH_USE>::dump (void) const
{
}

ACE_ALLOC_HOOK_DEFINE(ACE_Message_Queue_Iterator)

template <ACE_SYNCH_DECL>
ACE_Message_Queue_Reverse_Iterator<ACE_SYNCH_USE>::ACE_Message_Queue_Reverse_Iterator (ACE_Message_Queue <ACE_SYNCH_USE> &queue)
  : queue_ (queue),
    curr_ (queue_.tail_)
{
}

template <ACE_SYNCH_DECL> int 
ACE_Message_Queue_Reverse_Iterator<ACE_SYNCH_USE>::next (ACE_Message_Block *&entry)
{
  ACE_Read_Guard<ACE_SYNCH_MUTEX_T> m (this->queue_.lock_);

  if (this->curr_ != 0)
    {
      entry = this->curr_;
      return 1;
    }
  else
    return 0;
}

template <ACE_SYNCH_DECL> int 
ACE_Message_Queue_Reverse_Iterator<ACE_SYNCH_USE>::done (void) const
{
  ACE_Read_Guard<ACE_SYNCH_MUTEX_T> m (this->queue_.lock_);

  return this->curr_ == 0;
}

template <ACE_SYNCH_DECL> int
ACE_Message_Queue_Reverse_Iterator<ACE_SYNCH_USE>::advance (void)
{
  ACE_Read_Guard<ACE_SYNCH_MUTEX_T> m (this->queue_.lock_);

  this->curr_ = this->curr_->prev ();
  return this->curr_ != 0;
}

template <ACE_SYNCH_DECL> void 
ACE_Message_Queue_Reverse_Iterator<ACE_SYNCH_USE>::dump (void) const
{
}

template <ACE_SYNCH_DECL> void
ACE_Message_Queue<ACE_SYNCH_USE>::dump (void) const
{
  ACE_TRACE ("ACE_Message_Queue<ACE_SYNCH_USE>::dump");
  ACE_DEBUG ((LM_DEBUG, ACE_BEGIN_DUMP, this));
  ACE_DEBUG ((LM_DEBUG,
              "deactivated = %d\n"
              "low_water_mark = %d\n"
              "high_water_mark = %d\n"
              "cur_bytes = %d\n"
              "cur_count = %d\n"
              "head_ = %u\n"
              "tail_ = %u\n",
              this->deactivated_,
              this->low_water_mark_, 
              this->high_water_mark_,
              this->cur_bytes_, 
              this->cur_count_,
              this->head_,
              this->tail_));
  ACE_DEBUG ((LM_DEBUG,"not_full_cond: \n"));
  not_full_cond_.dump ();
  ACE_DEBUG ((LM_DEBUG,"not_empty_cond: \n"));
  not_empty_cond_.dump ();
  ACE_DEBUG ((LM_DEBUG, ACE_END_DUMP));
}

template <ACE_SYNCH_DECL>
ACE_Message_Queue<ACE_SYNCH_USE>::ACE_Message_Queue (size_t hwm, 
                                                     size_t lwm,
                                                     ACE_Notification_Strategy *ns)
#if defined (ACE_HAS_OPTIMIZED_MESSAGE_QUEUE)
  : not_empty_cond_ (0),
    not_full_cond_ (0),
    enqueue_waiters_ (0),
    dequeue_waiters_ (0)
#else
  : not_empty_cond_ (this->lock_),
    not_full_cond_ (this->lock_)
#endif /* ACE_HAS_OPTIMIZED_MESSAGE_QUEUE */
{
  ACE_TRACE ("ACE_Message_Queue<ACE_SYNCH_USE>::ACE_Message_Queue");

  if (this->open (hwm, lwm, ns) == -1)
    ACE_ERROR ((LM_ERROR, "open"));
}

template <ACE_SYNCH_DECL>
ACE_Message_Queue<ACE_SYNCH_USE>::~ACE_Message_Queue (void)
{
  ACE_TRACE ("ACE_Message_Queue<ACE_SYNCH_USE>::~ACE_Message_Queue");
  if (this->head_ != 0 && this->close () == -1)
    ACE_ERROR ((LM_ERROR, "close"));
}
  
// Don't bother locking since if someone calls this function more than
// once for the same queue, we're in bigger trouble than just
// concurrency control!

template <ACE_SYNCH_DECL> int 
ACE_Message_Queue<ACE_SYNCH_USE>::open (size_t hwm, 
                                        size_t lwm,
                                        ACE_Notification_Strategy *ns)
{
  ACE_TRACE ("ACE_Message_Queue<ACE_SYNCH_USE>::open");
  this->high_water_mark_ = hwm;
  this->low_water_mark_  = lwm;
  this->deactivated_ = 0;
  this->cur_bytes_ = 0;
  this->cur_count_ = 0;
  this->tail_ = 0;
  this->head_ = 0;
  this->notification_strategy_ = ns;
  return 0;
}

// Implementation of the public deactivate() method
// (assumes locks are held).

template <ACE_SYNCH_DECL> int
ACE_Message_Queue<ACE_SYNCH_USE>::deactivate_i (void)
{
  ACE_TRACE ("ACE_Message_Queue<ACE_SYNCH_USE>::deactivate_i");
  int current_status = 
    this->deactivated_ ? WAS_INACTIVE : WAS_ACTIVE;

  // Wakeup all waiters.
#if !defined (ACE_HAS_OPTIMIZED_MESSAGE_QUEUE)
  this->not_empty_cond_.broadcast ();
  this->not_full_cond_.broadcast ();
#endif /* ACE_HAS_OPTIMIZED_MESSAGE_QUEUE */

  this->deactivated_ = 1;
  return current_status;
}

template <ACE_SYNCH_DECL> int
ACE_Message_Queue<ACE_SYNCH_USE>::activate_i (void)
{
  ACE_TRACE ("ACE_Message_Queue<ACE_SYNCH_USE>::activate_i");
  int current_status = 
    this->deactivated_ ? WAS_INACTIVE : WAS_ACTIVE;
  this->deactivated_ = 0;
  return current_status;
}

// Clean up the queue if we have not already done so! 

template <ACE_SYNCH_DECL> int
ACE_Message_Queue<ACE_SYNCH_USE>::close (void)
{
  ACE_TRACE ("ACE_Message_Queue<ACE_SYNCH_USE>::close");
  ACE_GUARD_RETURN (ACE_SYNCH_MUTEX_T, ace_mon, this->lock_, -1);

  int res = this->deactivate_i ();

  // Free up the remaining message on the list 

  for (this->tail_ = 0; this->head_ != 0; )
    {
      this->cur_count_--;

      ACE_Message_Block *temp;

      // Decrement all the counts.
      for (temp = this->head_;
           temp != 0; 
           temp = temp->cont ())
        this->cur_bytes_ -= temp->size ();

      temp = this->head_;
      this->head_ = this->head_->next ();

      // Make sure to use <release> rather than <delete> since this is
      // reference counted.
      temp->release ();
    }

  return res;
}

template <ACE_SYNCH_DECL> int
ACE_Message_Queue<ACE_SYNCH_USE>::signal_enqueue_waiters (void)
{
#if !defined (ACE_HAS_OPTIMIZED_MESSAGE_QUEUE)
  if (this->not_full_cond_.signal () != 0)
    return -1;
#else
  if (this->enqueue_waiters_ > 0)
    {
      --this->enqueue_waiters_;
      return this->not_full_cond_.release ();
    }
#endif /* ACE_HAS_OPTIMIZED_MESSAGE_QUEUE */
  return 0;
}

template <ACE_SYNCH_DECL> int
ACE_Message_Queue<ACE_SYNCH_USE>::signal_dequeue_waiters (void)
{
#if !defined (ACE_HAS_OPTIMIZED_MESSAGE_QUEUE)
  // Tell any blocked threads that the queue has a new item!
  if (this->not_empty_cond_.signal () != 0)
    return -1;
#else
  if (this->dequeue_waiters_ > 0)
    {
      --this->dequeue_waiters_;
      return this->not_empty_cond_.release ();
    }
#endif /* ACE_HAS_OPTIMIZED_MESSAGE_QUEUE */
  return 0;
}

// Actually put the node at the end (no locking so must be called with
// locks held).

template <ACE_SYNCH_DECL> int
ACE_Message_Queue<ACE_SYNCH_USE>::enqueue_tail_i (ACE_Message_Block *new_item)
{
  ACE_TRACE ("ACE_Message_Queue<ACE_SYNCH_USE>::enqueue_tail_i");

  if (new_item == 0)
    return -1;

  // List was empty, so build a new one.
  if (this->tail_ == 0)
    {
      this->head_ = new_item;
      this->tail_ = new_item;
      new_item->next (0);
      new_item->prev (0);
    }
  // Link at the end.
  else 
    {
      new_item->next (0);
      this->tail_->next (new_item);
      new_item->prev (this->tail_);
      this->tail_ = new_item;
    }

  // Make sure to count *all* the bytes in a composite message!!! 

  for (ACE_Message_Block *temp = new_item; 
       temp != 0; 
       temp = temp->cont ())
    this->cur_bytes_ += temp->size ();

  this->cur_count_++;

  if (this->signal_dequeue_waiters () == -1)
    return -1;
  else
    return this->cur_count_;
}

// Actually put the node at the head (no locking) 

template <ACE_SYNCH_DECL> int
ACE_Message_Queue<ACE_SYNCH_USE>::enqueue_head_i (ACE_Message_Block *new_item)
{
  ACE_TRACE ("ACE_Message_Queue<ACE_SYNCH_USE>::enqueue_head_i");

  if (new_item == 0)
    return -1;

  new_item->prev (0);
  new_item->next (this->head_);

  if (this->head_ != 0)
      this->head_->prev (new_item);
  else
    this->tail_ = new_item;

  this->head_ = new_item;

  // Make sure to count *all* the bytes in a composite message!!!

  for (ACE_Message_Block *temp = new_item; 
       temp != 0; 
       temp = temp->cont ())
    this->cur_bytes_ += temp->size ();

  this->cur_count_++;

  if (this->signal_dequeue_waiters () == -1)
    return -1;
  else
    return this->cur_count_;
}

// Actually put the node at its proper position relative to its
// priority.

template <ACE_SYNCH_DECL> int
ACE_Message_Queue<ACE_SYNCH_USE>::enqueue_i (ACE_Message_Block *new_item)
{
  ACE_TRACE ("ACE_Message_Queue<ACE_SYNCH_USE>::enqueue_i");

  if (new_item == 0)
    return -1;

  if (this->head_ == 0)
    // Check for simple case of an empty queue, where all we need to
    // do is insert <new_item> into the head.
    return this->enqueue_head_i (new_item);
  else
    {
      ACE_Message_Block *temp;

      // Figure out where the new item goes relative to its priority.
      // We start looking from the highest priority to the lowest
      // priority.

      for (temp = this->tail_;
           temp != 0;
           temp = temp->prev ())
	if (temp->msg_priority () >= new_item->msg_priority ())
	  // Break out when we've located an item that has higher
	  // priority that <new_item>.
	  break;

      if (temp == 0)
        // Check for simple case of inserting at the head of the queue,
        // where all we need to do is insert <new_item> before the
        // current head.
        return this->enqueue_head_i (new_item);
      else if (temp->next () == 0)
        // Check for simple case of inserting at the end of the
        // queue, where all we need to do is insert <new_item> after
        // the current tail.
        return this->enqueue_tail_i (new_item);
      else
        {
          // Insert the message right before the item of equal or
          // higher priority.  This ensures that FIFO order is
          // maintained when messages of the same priority are
          // inserted consecutively.
          new_item->prev (temp);
          new_item->next (temp->next ());
          temp->next ()->prev (new_item);
          temp->next (new_item);
        }
    }

  // Make sure to count *all* the bytes in a composite message!!!

  for (ACE_Message_Block *temp = new_item; 
       temp != 0; 
       temp = temp->cont ())
    this->cur_bytes_ += temp->size ();

  this->cur_count_++;

  if (this->signal_dequeue_waiters () == -1)
    return -1;
  else
    return this->cur_count_;
}

// Actually get the first ACE_Message_Block (no locking, so must be
// called with locks held).  This method assumes that the queue has at
// least one item in it when it is called.

template <ACE_SYNCH_DECL> int
ACE_Message_Queue<ACE_SYNCH_USE>::dequeue_head_i (ACE_Message_Block *&first_item)
{
  ACE_TRACE ("ACE_Message_Queue<ACE_SYNCH_USE>::dequeue_head_i");
  first_item = this->head_;
  this->head_ = this->head_->next ();

  if (this->head_ == 0)
    this->tail_ = 0;
  else
    // The prev pointer of the first message block has to point to
    // NULL...
    this->head_->prev (0);

  // Make sure to subtract off all of the bytes associated with this
  // message.
  for (ACE_Message_Block *temp = first_item; 
       temp != 0; 
       temp = temp->cont ())
    this->cur_bytes_ -= temp->size ();

  this->cur_count_--;

  if (this->signal_enqueue_waiters () == -1)
    return -1;
  else
    return this->cur_count_;
}

// Take a look at the first item without removing it. 

template <ACE_SYNCH_DECL> int
ACE_Message_Queue<ACE_SYNCH_USE>::peek_dequeue_head (ACE_Message_Block *&first_item, 
                                                   ACE_Time_Value *tv)
{
  ACE_TRACE ("ACE_Message_Queue<ACE_SYNCH_USE>::peek_dequeue_head");
  ACE_GUARD_RETURN (ACE_SYNCH_MUTEX_T, ace_mon, this->lock_, -1);

  if (this->deactivated_)
    {
      errno = ESHUTDOWN;
      return -1;
    }

  // Wait for at least one item to become available 

  while (this->is_empty_i ())
    {
      if (this->not_empty_cond_.wait (tv) == -1)
        {
          if (errno == ETIME)
            errno = EWOULDBLOCK;
          return -1;
        }
      if (this->deactivated_)
        {
          errno = ESHUTDOWN;
          return -1;
        }
    }

  first_item = this->head_;
  return this->cur_count_;
}

template <ACE_SYNCH_DECL> int
ACE_Message_Queue<ACE_SYNCH_USE>::wait_not_full_cond (ACE_Guard<ACE_SYNCH_MUTEX_T> &mon,
						    ACE_Time_Value *tv)
{
#if defined (ACE_HAS_OPTIMIZED_MESSAGE_QUEUE)
  while (this->is_full_i ())
    {
      ++this->enqueue_waiters_;
      // @@ Need to add sanity checks for failure...
      mon.release ();
      this->not_full_cond_.acquire ();
      mon.acquire ();
    }
#else
  ACE_UNUSED_ARG (mon);

  // Wait while the queue is full.

  while (this->is_full_i ())
    {
      if (this->not_full_cond_.wait (tv) == -1)
        {
          if (errno == ETIME)
            errno = EWOULDBLOCK;
          return -1;
        }
      if (this->deactivated_)
        {
          errno = ESHUTDOWN;
          return -1;
        }
    }
#endif /* ACE_HAS_OPTIMIZED_MESSAGE_QUEUE */
  return 0;
}

template <ACE_SYNCH_DECL> int
ACE_Message_Queue<ACE_SYNCH_USE>::wait_not_empty_cond (ACE_Guard<ACE_SYNCH_MUTEX_T> &mon, 
						     ACE_Time_Value *tv)
{
#if defined (ACE_HAS_OPTIMIZED_MESSAGE_QUEUE)
  while (this->is_empty_i ())
    {
      ++this->dequeue_waiters_;
      // @@ Need to add sanity checks for failure...
      mon.release ();
      this->not_empty_cond_.acquire ();
      mon.acquire ();
    }
#else
  ACE_UNUSED_ARG (mon);

  // Wait while the queue is empty.

  while (this->is_empty_i ())
    {
      if (this->not_empty_cond_.wait (tv) == -1)
        {
          if (errno == ETIME)
            errno = EWOULDBLOCK;
          return -1;
        }
      if (this->deactivated_)
        {
          errno = ESHUTDOWN;
          return -1;
        }
    }
#endif /* ACE_HAS_OPTIMIZED_MESSAGE_QUEUE */
  return 0;
}

// Block indefinitely waiting for an item to arrive,
// does not ignore alerts (e.g., signals). 

template <ACE_SYNCH_DECL> int 
ACE_Message_Queue<ACE_SYNCH_USE>::enqueue_head (ACE_Message_Block *new_item, 
                                              ACE_Time_Value *tv)
{
  ACE_TRACE ("ACE_Message_Queue<ACE_SYNCH_USE>::enqueue_head");
  ACE_GUARD_RETURN (ACE_SYNCH_MUTEX_T, ace_mon, this->lock_, -1);

  if (this->deactivated_)
    {
      errno = ESHUTDOWN;
      return -1;
    }

  if (this->wait_not_full_cond (ace_mon, tv) == -1)
    return -1;

  int queue_count = this->enqueue_head_i (new_item);

  if (queue_count == -1)
    return -1;
  else
    {
      this->notify ();
      return queue_count;
    }
}

// Enqueue an <ACE_Message_Block *> into the <Message_Queue> in
// accordance with its <msg_priority> (0 is lowest priority).  Returns
// -1 on failure, else the number of items still on the queue.

template <ACE_SYNCH_DECL> int 
ACE_Message_Queue<ACE_SYNCH_USE>::enqueue_prio (ACE_Message_Block *new_item, 
                                              ACE_Time_Value *tv)
{
  ACE_TRACE ("ACE_Message_Queue<ACE_SYNCH_USE>::enqueue_prio");
  ACE_GUARD_RETURN (ACE_SYNCH_MUTEX_T, ace_mon, this->lock_, -1);

  if (this->deactivated_)
    {
      errno = ESHUTDOWN;
      return -1;
    }

  if (this->wait_not_full_cond (ace_mon, tv) == -1)
    return -1;

  int queue_count = this->enqueue_i (new_item);

  if (queue_count == -1)
    return -1;
  else
    {
      this->notify ();
      return queue_count;
    }
}

template <ACE_SYNCH_DECL> int 
ACE_Message_Queue<ACE_SYNCH_USE>::enqueue (ACE_Message_Block *new_item, 
                                         ACE_Time_Value *tv)
{
  ACE_TRACE ("ACE_Message_Queue<ACE_SYNCH_USE>::enqueue");
  return this->enqueue_prio (new_item, tv);
}

// Block indefinitely waiting for an item to arrive,
// does not ignore alerts (e.g., signals). 

template <ACE_SYNCH_DECL> int 
ACE_Message_Queue<ACE_SYNCH_USE>::enqueue_tail (ACE_Message_Block *new_item, 
                                              ACE_Time_Value *tv)
{
  ACE_TRACE ("ACE_Message_Queue<ACE_SYNCH_USE>::enqueue_tail");
  ACE_GUARD_RETURN (ACE_SYNCH_MUTEX_T, ace_mon, this->lock_, -1);

  if (this->deactivated_)
    {
      errno = ESHUTDOWN;
      return -1;
    }

  if (this->wait_not_full_cond (ace_mon, tv) == -1)
    return -1;

  int queue_count = this->enqueue_tail_i (new_item);

  if (queue_count == -1)
    return -1;
  else
    {
      this->notify ();
      return queue_count;
    }
}

// Remove an item from the front of the queue.  If TV == 0 block 
// indefinitely (or until an alert occurs).  Otherwise, block for upto
// the amount of time specified by TV. 

template <ACE_SYNCH_DECL> int 
ACE_Message_Queue<ACE_SYNCH_USE>::dequeue_head (ACE_Message_Block *&first_item, 
                                              ACE_Time_Value *tv)
{
  ACE_TRACE ("ACE_Message_Queue<ACE_SYNCH_USE>::dequeue_head");
  ACE_GUARD_RETURN (ACE_SYNCH_MUTEX_T, ace_mon, this->lock_, -1);

  if (this->deactivated_)
    {
      errno = ESHUTDOWN;
      return -1;
    }

  if (this->wait_not_empty_cond (ace_mon, tv) == -1)
    return -1;

  return this->dequeue_head_i (first_item);
}

template <ACE_SYNCH_DECL> int
ACE_Message_Queue<ACE_SYNCH_USE>::notify (void)
{
  ACE_TRACE ("ACE_Message_Queue<ACE_SYNCH_USE>::notify");

  // By default, don't do anything.
  if (this->notification_strategy_ == 0)
    return 0;
  else
    return this->notification_strategy_->notify ();
}

#endif /* ACE_MESSAGE_QUEUE_C */