/*

* Copyright (c) 1999 - 2001 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the License "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description: 

*

*/

/*****************************************************************

  File name:  nwx_psq.c

  Part of: Protected Signaled Queue 

  Version: V1.0

  Description: 

    Provides interfaces to a Protected, Signaled, Queue. This is a queue that

  can be have multiple readers and writers running in separate threads.

  When something is added to the queue a signal is set.

******************************************************************/

/*

**-------------------------------------------------------------------------

**  Include Files

**-------------------------------------------------------------------------

*/

#include "nwx_psq.h"

#include "nwx_string.h"

#include "nwx_logger.h"

#include "nwx_datastruct.h"

#include "BrsrStatusCodes.h"

/*

**-------------------------------------------------------------------------

**  Constants

**-------------------------------------------------------------------------

*/

/*

**-------------------------------------------------------------------------

**  Internal Types

**-------------------------------------------------------------------------

*/

/*

**-------------------------------------------------------------------------

**  Macros

**-------------------------------------------------------------------------

*/

/*

**-------------------------------------------------------------------------

**  Internal Prototypes

**-------------------------------------------------------------------------

*/

/*

**-------------------------------------------------------------------------

**  File Scoped Static Variables

**-------------------------------------------------------------------------

*/

/*

**-------------------------------------------------------------------------

**  Global Variable Definitions

**-------------------------------------------------------------------------

*/

/*

**-------------------------------------------------------------------------

**  Internal Functions

**-------------------------------------------------------------------------

*/

/*

**-------------------------------------------------------------------------

**  External Public (Exported) Functions

**-------------------------------------------------------------------------

*/

/*****************************************************************

**  Name:   NW_Psq_New

**  Description:  Creates a new Psq object.

**  Parameters:   *name - name of queue for debugging  

**  Return Value: a pointer to the new Psq object or NULL

******************************************************************/

NW_Psq_t *NW_Psq_New(const char *name)

{

  NW_Psq_t *que;

  NW_ASSERT(name != NULL);

  que = (NW_Psq_t*) NW_Mem_Malloc(sizeof(NW_Psq_t));

  if (que != NULL) {

    que->head = NULL;

    que->tail = NULL;

    que->length = 0;

    que->signal = (NW_Osu_Signal_t*) NW_Osu_NewSignal(name);

    if (que->signal == NULL)

    {

      NW_Mem_Free(que);

      return NULL;

    }

    que->mutex  = (NW_Osu_Mutex_t*) NW_Osu_NewMutex(name);

    if (que->mutex == NULL)

    {

      NW_Osu_DeleteSignal(que->signal);

      NW_Mem_Free(que);

      return NULL;

    }

    que->name   = NW_Str_CvtFromAscii(name);

    if (que->name == NULL) {

      NW_Osu_DeleteSignal(que->signal);

      NW_Osu_DeleteMutex(que->mutex);

      NW_Mem_Free(que);

      return NULL;

    }

  }

  return que;

}

/*****************************************************************

**  Name:   NW_Psq_Delete

**  Description:  Delete a Psq object

**  Parameters:   *que - a pointer to the queue 

**  Return Value: void

**  Note: caller *must* insure that both signal and mutex

**        are no longer in use prior to deleting the Psq object.

******************************************************************/

void NW_Psq_Delete(NW_Psq_t *que)

{

  NW_ASSERT(que != NULL);

  if (que->signal != NULL)

    NW_Osu_DeleteSignal(que->signal);

  if (que->mutex != NULL)

    NW_Osu_DeleteMutex(que->mutex);

  if (que->name != NULL)

    NW_Str_Delete(que->name);

  NW_Mem_Free(que);

  return;

}

/*****************************************************************

**  Name:   NW_Psq_AddTail

**  Description:  Add a new node to the tail of the queue

**  Parameters:   *que - a pointer to the queue 

**                *node - pointer to the new node 

**  Return Value: void

******************************************************************/

void NW_Psq_AddTail(NW_Psq_t *que, NW_Node_t *node)

{

  NW_ASSERT(que != NULL);

  NW_ASSERT(node != NULL);

  NW_LOG2(NW_LOG_LEVEL5, "addTail on queue %s length %d\n",

          que->name, que->length);

  /* lock the mutex and wait as long as needed */

  NW_Osu_LockMutex(que->mutex);

  /* do the add */

  if (que->head == NULL) {

    que->head = node;

  } else {

    que->tail->next = node;

  }

  que->tail = node;

  que->tail->next = NULL;

  que->length++;

  /* unlock the mutex and set signal */

  NW_Osu_UnlockMutex(que->mutex);

  NW_Osu_NotifySignal(que->signal);

  return;

}

/*****************************************************************

**  Name:   NW_Psq_RemoveHead

**  Description:  Return node from the head of the queue and remove it

**  Parameters:   *que - a pointer to the queue 

**  Return Value: pointer to removed node

******************************************************************/

NW_Node_t *NW_Psq_RemoveHead(NW_Psq_t *que)

{

  NW_Node_t *tmp=NULL;

  NW_ASSERT(que != NULL);

  NW_LOG2(NW_LOG_LEVEL5, "removeHead on queue %s length %d\n",

          que->name, que->length);

  /* lock the mutex and wait as long as needed */

  NW_Osu_LockMutex(que->mutex);

  /* do the remove */

  if (que->head != NULL) {

    tmp = que->head;

    que->head = tmp->next;

    if (que->head == NULL)

      que->tail = NULL;

    que->length--;

  }

  /* unlock the mutex */

  NW_Osu_UnlockMutex(que->mutex);

  /* return the node */

  return tmp;

}

/*****************************************************************

**  Name:   NW_Psq_WaitForAdd

**  Description:  Wait for a node to be added to the queue

**  Parameters:   *que - a pointer to the queue

**                howLong - number mSec to wait or NW_WAIT_FOREVER

**  Return Value: KBrsrSuccess if node is queued, else KBrsrWaitTimeout

******************************************************************/

TBrowserStatusCode NW_Psq_WaitForAdd(const NW_Psq_t *que, const NW_Int32 howLong)

{

  /* NW_LOG1(NW_LOG_ALL, "wait on queue %s\n", que->name); */

  return NW_Osu_WaitOnSignal(que->signal, howLong);

}