/* GLIB - Library of useful routines for C programming

 * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald

 *

 * GAsyncQueue: asynchronous queue implementation, based on Gqueue.

 * Copyright (C) 2000 Sebastian Wilhelmi; University of Karlsruhe

 * Portions copyright (c) 2006 Nokia Corporation.  All rights reserved.

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, write to the

 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,

 * Boston, MA 02111-1307, USA.

 */

/*

 * MT safe

 */

#include "config.h"

#include "glib.h"

#include "galias.h"

#ifdef __SYMBIAN32__

#include <glib_wsd.h>

#endif /* __SYMBIAN32__ */

#if EMULATOR

#define g_thread_functions_for_glib_use (*_g_thread_functions_for_glib_use())

#define g_thread_use_default_impl (*_g_thread_use_default_impl())

#endif /* EMULATOR */

struct _GAsyncQueue

{

  GMutex *mutex;

  GCond *cond;

  GQueue *queue;

  guint waiting_threads;

  gint32 ref_count;

};

typedef struct {

  GCompareDataFunc func;

  gpointer         user_data;

} SortData;

/**

 * g_async_queue_new:

 * 

 * Creates a new asynchronous queue with the initial reference count of 1.

 * 

 * Return value: the new #GAsyncQueue.

 **/

EXPORT_C GAsyncQueue*

g_async_queue_new (void)

{

  GAsyncQueue* retval = g_new (GAsyncQueue, 1);

  retval->mutex = g_mutex_new ();

  retval->cond = NULL;

  retval->queue = g_queue_new ();

  retval->waiting_threads = 0;

  retval->ref_count = 1;

  return retval;

}

/**

 * g_async_queue_ref:

 * @queue: a #GAsyncQueue.

 *

 * Increases the reference count of the asynchronous @queue by 1. You

 * do not need to hold the lock to call this function.

 *

 * Returns: the @queue that was passed in (since 2.6)

 **/

EXPORT_C GAsyncQueue *

g_async_queue_ref (GAsyncQueue *queue)

{

  g_return_val_if_fail (queue, NULL);

  g_return_val_if_fail (g_atomic_int_get (&queue->ref_count) > 0, NULL);

  g_atomic_int_inc (&queue->ref_count);

  return queue;

}

/**

 * g_async_queue_ref_unlocked:

 * @queue: a #GAsyncQueue.

 * 

 * Increases the reference count of the asynchronous @queue by 1.

 *

 * @Deprecated: Since 2.8, reference counting is done atomically

 * so g_async_queue_ref() can be used regardless of the @queue's

 * lock.

 **/

EXPORT_C void 

g_async_queue_ref_unlocked (GAsyncQueue *queue)

{

  g_return_if_fail (queue);

  g_return_if_fail (g_atomic_int_get (&queue->ref_count) > 0);

  g_atomic_int_inc (&queue->ref_count);

}

/**

 * g_async_queue_unref_and_unlock:

 * @queue: a #GAsyncQueue.

 * 

 * Decreases the reference count of the asynchronous @queue by 1 and

 * releases the lock. This function must be called while holding the

 * @queue's lock. If the reference count went to 0, the @queue will be

 * destroyed and the memory allocated will be freed.

 *

 * @Deprecated: Since 2.8, reference counting is done atomically

 * so g_async_queue_unref() can be used regardless of the @queue's

 * lock.

 **/

EXPORT_C void 

g_async_queue_unref_and_unlock (GAsyncQueue *queue)

{

  g_return_if_fail (queue);

  g_return_if_fail (g_atomic_int_get (&queue->ref_count) > 0);

  g_mutex_unlock (queue->mutex);

  g_async_queue_unref (queue);

}

/**

 * g_async_queue_unref:

 * @queue: a #GAsyncQueue.

 * 

 * Decreases the reference count of the asynchronous @queue by 1. If

 * the reference count went to 0, the @queue will be destroyed and the

 * memory allocated will be freed. So you are not allowed to use the

 * @queue afterwards, as it might have disappeared. You do not need to

 * hold the lock to call this function.

 **/

EXPORT_C void 

g_async_queue_unref (GAsyncQueue *queue)

{

  g_return_if_fail (queue);

  g_return_if_fail (g_atomic_int_get (&queue->ref_count) > 0);

  if (g_atomic_int_dec_and_test (&queue->ref_count))

    {

      g_return_if_fail (queue->waiting_threads == 0);

      g_mutex_free (queue->mutex);

      if (queue->cond)

	g_cond_free (queue->cond);

      g_queue_free (queue->queue);

      g_free (queue);

    }

}

/**

 * g_async_queue_lock:

 * @queue: a #GAsyncQueue.

 * 

 * Acquires the @queue's lock. After that you can only call the

 * <function>g_async_queue_*_unlocked()</function> function variants on that

 * @queue. Otherwise it will deadlock.

 **/

EXPORT_C void

g_async_queue_lock (GAsyncQueue *queue)

{

  g_return_if_fail (queue);

  g_return_if_fail (g_atomic_int_get (&queue->ref_count) > 0);

  g_mutex_lock (queue->mutex);

}

/**

 * g_async_queue_unlock:

 * @queue: a #GAsyncQueue.

 * 

 * Releases the queue's lock.

 **/

EXPORT_C void 

g_async_queue_unlock (GAsyncQueue *queue)

{

  g_return_if_fail (queue);

  g_return_if_fail (g_atomic_int_get (&queue->ref_count) > 0);

  g_mutex_unlock (queue->mutex);

}

/**

 * g_async_queue_push:

 * @queue: a #GAsyncQueue.

 * @data: @data to push into the @queue.

 *

 * Pushes the @data into the @queue. @data must not be %NULL.

 **/

EXPORT_C void

g_async_queue_push (GAsyncQueue* queue, gpointer data)

{

  g_return_if_fail (queue);

  g_return_if_fail (g_atomic_int_get (&queue->ref_count) > 0);

  g_return_if_fail (data);

  g_mutex_lock (queue->mutex);

  g_async_queue_push_unlocked (queue, data);

  g_mutex_unlock (queue->mutex);

}

/**

 * g_async_queue_push_unlocked:

 * @queue: a #GAsyncQueue.

 * @data: @data to push into the @queue.

 * 

 * Pushes the @data into the @queue. @data must not be %NULL. This

 * function must be called while holding the @queue's lock.

 **/

EXPORT_C void

g_async_queue_push_unlocked (GAsyncQueue* queue, gpointer data)

{

  g_return_if_fail (queue);

  g_return_if_fail (g_atomic_int_get (&queue->ref_count) > 0);

  g_return_if_fail (data);

  g_queue_push_head (queue->queue, data);

  if (queue->waiting_threads > 0)

    g_cond_signal (queue->cond);

}

/**

 * g_async_queue_push_sorted:

 * @queue: a #GAsyncQueue

 * @data: the @data to push into the @queue

 * @func: the #GCompareDataFunc is used to sort @queue. This function

 *     is passed two elements of the @queue. The function should return

 *     0 if they are equal, a negative value if the first element

 *     should be higher in the @queue or a positive value if the first

 *     element should be lower in the @queue than the second element.

 * @user_data: user data passed to @func.

 * 

 * Inserts @data into @queue using @func to determine the new

 * position. 

 * 

 * This function requires that the @queue is sorted before pushing on

 * new elements.

 * 

 * This function will lock @queue before it sorts the queue and unlock

 * it when it is finished.

 * 

 * For an example of @func see g_async_queue_sort(). 

 *

 * Since: 2.10

 **/

EXPORT_C void

g_async_queue_push_sorted (GAsyncQueue      *queue,

			   gpointer          data,

			   GCompareDataFunc  func,

			   gpointer          user_data)

{

  g_return_if_fail (queue != NULL);

  g_mutex_lock (queue->mutex);

  g_async_queue_push_sorted_unlocked (queue, data, func, user_data);

  g_mutex_unlock (queue->mutex);

}

static gint 

g_async_queue_invert_compare (gpointer  v1, 

			      gpointer  v2, 

			      SortData *sd)

{

  return -sd->func (v1, v2, sd->user_data);

}

/**

 * g_async_queue_push_sorted_unlocked:

 * @queue: a #GAsyncQueue

 * @data: the @data to push into the @queue

 * @func: the #GCompareDataFunc is used to sort @queue. This function

 *     is passed two elements of the @queue. The function should return

 *     0 if they are equal, a negative value if the first element

 *     should be higher in the @queue or a positive value if the first

 *     element should be lower in the @queue than the second element.

 * @user_data: user data passed to @func.

 * 

 * Inserts @data into @queue using @func to determine the new

 * position.

 * 

 * This function requires that the @queue is sorted before pushing on

 * new elements.

 * 

 * This function is called while holding the @queue's lock.

 * 

 * For an example of @func see g_async_queue_sort(). 

 *

 * Since: 2.10

 **/

EXPORT_C void

g_async_queue_push_sorted_unlocked (GAsyncQueue      *queue,

				    gpointer          data,

				    GCompareDataFunc  func,

				    gpointer          user_data)

{

  SortData sd;

  g_return_if_fail (queue != NULL);

  sd.func = func;

  sd.user_data = user_data;

  g_queue_insert_sorted (queue->queue, 

			 data, 

			 (GCompareDataFunc)g_async_queue_invert_compare, 

			 &sd);

  if (queue->waiting_threads > 0)

    g_cond_signal (queue->cond);

}

static gpointer

g_async_queue_pop_intern_unlocked (GAsyncQueue *queue, 

				   gboolean     try, 

				   GTimeVal    *end_time)

{

  gpointer retval;

  if (!g_queue_peek_tail_link (queue->queue))

    {

      if (try)

	return NULL;

      if (!queue->cond)

	queue->cond = g_cond_new ();

      if (!end_time)

        {

          queue->waiting_threads++;

	  while (!g_queue_peek_tail_link (queue->queue))

            g_cond_wait (queue->cond, queue->mutex);

          queue->waiting_threads--;

        }

      else

        {

          queue->waiting_threads++;

          while (!g_queue_peek_tail_link (queue->queue))

            if (!g_cond_timed_wait (queue->cond, queue->mutex, end_time))

              break;

          queue->waiting_threads--;

          if (!g_queue_peek_tail_link (queue->queue))

	    return NULL;

        }

    }

  retval = g_queue_pop_tail (queue->queue);

  g_assert (retval);

  return retval;

}

/**

 * g_async_queue_pop:

 * @queue: a #GAsyncQueue.

 * 

 * Pops data from the @queue. This function blocks until data become

 * available.

 *

 * Return value: data from the queue.

 **/

EXPORT_C gpointer

g_async_queue_pop (GAsyncQueue* queue)

{

  gpointer retval;

  g_return_val_if_fail (queue, NULL);

  g_return_val_if_fail (g_atomic_int_get (&queue->ref_count) > 0, NULL);

  g_mutex_lock (queue->mutex);

  retval = g_async_queue_pop_intern_unlocked (queue, FALSE, NULL);

  g_mutex_unlock (queue->mutex);

  return retval;

}

/**

 * g_async_queue_pop_unlocked:

 * @queue: a #GAsyncQueue.

 * 

 * Pops data from the @queue. This function blocks until data become

 * available. This function must be called while holding the @queue's

 * lock.

 *

 * Return value: data from the queue.

 **/

EXPORT_C gpointer

g_async_queue_pop_unlocked (GAsyncQueue* queue)

{

  g_return_val_if_fail (queue, NULL);

  g_return_val_if_fail (g_atomic_int_get (&queue->ref_count) > 0, NULL);

  return g_async_queue_pop_intern_unlocked (queue, FALSE, NULL);

}

/**

 * g_async_queue_try_pop:

 * @queue: a #GAsyncQueue.

 * 

 * Tries to pop data from the @queue. If no data is available, %NULL is

 * returned.

 *

 * Return value: data from the queue or %NULL, when no data is

 * available immediately.

 **/

EXPORT_C gpointer

g_async_queue_try_pop (GAsyncQueue* queue)

{

  gpointer retval;

  g_return_val_if_fail (queue, NULL);

  g_return_val_if_fail (g_atomic_int_get (&queue->ref_count) > 0, NULL);

  g_mutex_lock (queue->mutex);

  retval = g_async_queue_pop_intern_unlocked (queue, TRUE, NULL);

  g_mutex_unlock (queue->mutex);

  return retval;

}

/**

 * g_async_queue_try_pop_unlocked:

 * @queue: a #GAsyncQueue.

 * 

 * Tries to pop data from the @queue. If no data is available, %NULL is

 * returned. This function must be called while holding the @queue's

 * lock.

 *

 * Return value: data from the queue or %NULL, when no data is

 * available immediately.

 **/

EXPORT_C gpointer

g_async_queue_try_pop_unlocked (GAsyncQueue* queue)

{

  g_return_val_if_fail (queue, NULL);

  g_return_val_if_fail (g_atomic_int_get (&queue->ref_count) > 0, NULL);

  return g_async_queue_pop_intern_unlocked (queue, TRUE, NULL);

}

/**

 * g_async_queue_timed_pop:

 * @queue: a #GAsyncQueue.

 * @end_time: a #GTimeVal, determining the final time.

 *

 * Pops data from the @queue. If no data is received before @end_time,

 * %NULL is returned.

 *

 * To easily calculate @end_time a combination of g_get_current_time()

 * and g_time_val_add() can be used.

 *

 * Return value: data from the queue or %NULL, when no data is

 * received before @end_time.

 **/

EXPORT_C gpointer

g_async_queue_timed_pop (GAsyncQueue* queue, GTimeVal *end_time)

{

  gpointer retval;

  g_return_val_if_fail (queue, NULL);

  g_return_val_if_fail (g_atomic_int_get (&queue->ref_count) > 0, NULL);

  g_mutex_lock (queue->mutex);

  retval = g_async_queue_pop_intern_unlocked (queue, FALSE, end_time);

  g_mutex_unlock (queue->mutex);

  return retval;  

}

/**

 * g_async_queue_timed_pop_unlocked:

 * @queue: a #GAsyncQueue.

 * @end_time: a #GTimeVal, determining the final time.

 *

 * Pops data from the @queue. If no data is received before @end_time,

 * %NULL is returned. This function must be called while holding the

 * @queue's lock.

 *

 * To easily calculate @end_time a combination of g_get_current_time()

 * and g_time_val_add() can be used.

 *

 * Return value: data from the queue or %NULL, when no data is

 * received before @end_time.

 **/

EXPORT_C gpointer

g_async_queue_timed_pop_unlocked (GAsyncQueue* queue, GTimeVal *end_time)

{

  g_return_val_if_fail (queue, NULL);

  g_return_val_if_fail (g_atomic_int_get (&queue->ref_count) > 0, NULL);

  return g_async_queue_pop_intern_unlocked (queue, FALSE, end_time);

}

/**

 * g_async_queue_length:

 * @queue: a #GAsyncQueue.

 * 

 * Returns the length of the queue, negative values mean waiting

 * threads, positive values mean available entries in the

 * @queue. Actually this function returns the number of data items in

 * the queue minus the number of waiting threads. Thus a return value

 * of 0 could mean 'n' entries in the queue and 'n' thread waiting.

 * That can happen due to locking of the queue or due to

 * scheduling.  

 *

 * Return value: the length of the @queue.

 **/

EXPORT_C gint

g_async_queue_length (GAsyncQueue* queue)

{

  gint retval;

  g_return_val_if_fail (queue, 0);

  g_return_val_if_fail (g_atomic_int_get (&queue->ref_count) > 0, 0);

  g_mutex_lock (queue->mutex);