/*
 *  CORE Message Queue Handler
 *
 *  DESCRIPTION:
 *
 *  This package is the implementation of the CORE Message Queue Handler.
 *  This core object provides task synchronization and communication functions
 *  via messages passed to queue objects.
 *
 *  COPYRIGHT (c) 1989-1999.
 *  On-Line Applications Research Corporation (OAR).
 *
 *  The license and distribution terms for this file may be
 *  found in the file LICENSE in this distribution or at
 *  http://www.OARcorp.com/rtems/license.html.
 *
 *  $Id$
 */

#include <rtems/system.h>
#include <rtems/score/chain.h>
#include <rtems/score/isr.h>
#include <rtems/score/object.h>
#include <rtems/score/coremsg.h>
#include <rtems/score/states.h>
#include <rtems/score/thread.h>
#include <rtems/score/wkspace.h>
#if defined(RTEMS_MULTIPROCESSING)
#include <rtems/score/mpci.h>
#endif

/*PAGE
 *
 *  _CORE_message_queue_Insert_message
 *
 *  This kernel routine inserts the specified message into the
 *  message queue.  It is assumed that the message has been filled
 *  in before this routine is called.
 *
 *  Input parameters:
 *    the_message_queue - pointer to message queue
 *    the_message       - message to insert
 *    priority          - insert indication
 *
 *  Output parameters:  NONE
 *
 *  INTERRUPT LATENCY:
 *    insert
 */

void _CORE_message_queue_Insert_message(
  CORE_message_queue_Control        *the_message_queue,
  CORE_message_queue_Buffer_control *the_message,
  CORE_message_queue_Submit_types    submit_type
)
{
  the_message_queue->number_of_pending_messages += 1;

  the_message->priority = submit_type;

  switch ( submit_type ) {
    case CORE_MESSAGE_QUEUE_SEND_REQUEST:
      _CORE_message_queue_Append( the_message_queue, the_message );
      break;
    case CORE_MESSAGE_QUEUE_URGENT_REQUEST:
      _CORE_message_queue_Prepend( the_message_queue, the_message );
      break;
    default:
      /* XXX interrupt critical section needs to be addressed */
      {
        CORE_message_queue_Buffer_control *this_message;
        Chain_Node                        *the_node;
        Chain_Control                     *the_header;

        the_header = &the_message_queue->Pending_messages;
        the_node = the_header->first;
        while ( !_Chain_Is_tail( the_header, the_node ) ) {

          this_message = (CORE_message_queue_Buffer_control *) the_node;

          if ( this_message->priority <= the_message->priority ) {
            the_node = the_node->next;
            continue;
          }

          break;
        }
        _Chain_Insert( the_node->previous, &the_message->Node );
      }
      break;
  }

  /*
   *  According to POSIX, does this happen before or after the message
   *  is actually enqueued.  It is logical to think afterwards, because
   *  the message is actually in the queue at this point.
   */

  if ( the_message_queue->number_of_pending_messages == 1 && 
       the_message_queue->notify_handler )
    (*the_message_queue->notify_handler)( the_message_queue->notify_argument );
}