| /* 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 |
| * |
| * 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 "glib.h" |
| |
| struct _GAsyncQueue |
| { |
| GMutex *mutex; |
| GCond *cond; |
| GQueue *queue; |
| guint waiting_threads; |
| guint ref_count; |
| }; |
| |
| /** |
| * g_async_queue_new: |
| * |
| * Creates a new asynchronous queue with the initial reference count of 1. |
| * |
| * Return value: the new #GAsyncQueue. |
| **/ |
| GAsyncQueue* |
| g_async_queue_new () |
| { |
| GAsyncQueue* retval = g_new (GAsyncQueue, 1); |
| retval->mutex = g_mutex_new (); |
| retval->cond = g_cond_new (); |
| 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. |
| **/ |
| void |
| g_async_queue_ref (GAsyncQueue *queue) |
| { |
| g_return_if_fail (queue); |
| g_return_if_fail (queue->ref_count > 0); |
| |
| g_mutex_lock (queue->mutex); |
| queue->ref_count++; |
| g_mutex_unlock (queue->mutex); |
| } |
| |
| /** |
| * g_async_queue_ref_unlocked: |
| * @queue: a #GAsyncQueue. |
| * |
| * Increases the reference count of the asynchronous @queue by 1. This |
| * function must be called while holding the @queue's lock. |
| **/ |
| void |
| g_async_queue_ref_unlocked (GAsyncQueue *queue) |
| { |
| g_return_if_fail (queue); |
| g_return_if_fail (queue->ref_count > 0); |
| |
| 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. So you are not |
| * allowed to use the @queue afterwards, as it might have disappeared. |
| * The obvious asymmetry (it is not named |
| * g_async_queue_unref_unlocked) is because the queue can't be |
| * unlocked after dereffing it, as it might already have disappeared. |
| **/ |
| void |
| g_async_queue_unref_and_unlock (GAsyncQueue *queue) |
| { |
| gboolean stop; |
| |
| g_return_if_fail (queue); |
| g_return_if_fail (queue->ref_count > 0); |
| |
| queue->ref_count--; |
| stop = (queue->ref_count == 0); |
| g_mutex_unlock (queue->mutex); |
| |
| if (stop) |
| { |
| g_return_if_fail (queue->waiting_threads == 0); |
| g_mutex_free (queue->mutex); |
| g_cond_free (queue->cond); |
| g_queue_free (queue->queue); |
| g_free (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. |
| **/ |
| void |
| g_async_queue_unref (GAsyncQueue *queue) |
| { |
| g_return_if_fail (queue); |
| g_return_if_fail (queue->ref_count > 0); |
| |
| g_mutex_lock (queue->mutex); |
| g_async_queue_unref_and_unlock (queue); |
| } |
| |
| /** |
| * g_async_queue_lock: |
| * @queue: a #GAsyncQueue. |
| * |
| * Acquire the @queue's lock. After that you can only call the |
| * g_async_queue_*_unlocked function variants on that |
| * @queue. Otherwise it will deadlock. |
| **/ |
| void |
| g_async_queue_lock (GAsyncQueue *queue) |
| { |
| g_return_if_fail (queue); |
| g_return_if_fail (queue->ref_count > 0); |
| |
| g_mutex_lock (queue->mutex); |
| } |
| |
| /** |
| * g_async_queue_unlock: |
| * @queue: a #GAsyncQueue. |
| * |
| * Release the queue's lock. |
| **/ |
| void |
| g_async_queue_unlock (GAsyncQueue *queue) |
| { |
| g_return_if_fail (queue); |
| g_return_if_fail (queue->ref_count > 0); |
| |
| g_mutex_unlock (queue->mutex); |
| } |
| |
| /** |
| * g_async_queue_push: |
| * @queue: a #GAsyncQueue. |
| * @data: @data to push into the @queue. |
| * |
| * Push the @data into the @queue. @data must not be #NULL. |
| **/ |
| void |
| g_async_queue_push (GAsyncQueue* queue, gpointer data) |
| { |
| g_return_if_fail (queue); |
| g_return_if_fail (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. |
| * |
| * Push the @data into the @queue. @data must not be #NULL. This |
| * function must be called while holding the @queue's lock. |
| **/ |
| void |
| g_async_queue_push_unlocked (GAsyncQueue* queue, gpointer data) |
| { |
| g_return_if_fail (queue); |
| g_return_if_fail (queue->ref_count > 0); |
| g_return_if_fail (data); |
| |
| g_queue_push_head (queue->queue, data); |
| 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 (queue->queue)) |
| { |
| if (try) |
| return NULL; |
| if (!end_time) |
| { |
| queue->waiting_threads++; |
| while (!g_queue_peek_tail (queue->queue)) |
| g_cond_wait(queue->cond, queue->mutex); |
| queue->waiting_threads--; |
| } |
| else |
| { |
| queue->waiting_threads++; |
| while (!g_queue_peek_tail (queue->queue)) |
| if (!g_cond_timed_wait (queue->cond, queue->mutex, end_time)) |
| break; |
| queue->waiting_threads--; |
| if (!g_queue_peek_tail (queue->queue)) |
| return NULL; |
| } |
| } |
| |
| retval = g_queue_pop_tail (queue->queue); |
| |
| g_assert (retval); |
| |
| return retval; |
| } |
| |
| /** |
| * g_async_queue_pop: |
| * @queue: a #GAsyncQueue. |
| * |
| * Pop data from the @queue. This function blocks until data become |
| * available. |
| * |
| * Return value: data from the queue. |
| **/ |
| gpointer |
| g_async_queue_pop (GAsyncQueue* queue) |
| { |
| gpointer retval; |
| |
| g_return_val_if_fail (queue, NULL); |
| g_return_val_if_fail (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. |
| * |
| * Pop 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. |
| **/ |
| gpointer |
| g_async_queue_pop_unlocked (GAsyncQueue* queue) |
| { |
| g_return_val_if_fail (queue, NULL); |
| g_return_val_if_fail (queue->ref_count > 0, NULL); |
| |
| return g_async_queue_pop_intern_unlocked (queue, FALSE, NULL); |
| } |
| |
| /** |
| * g_async_queue_try_pop: |
| * @queue: a #GAsyncQueue. |
| * |
| * Try 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. |
| **/ |
| gpointer |
| g_async_queue_try_pop (GAsyncQueue* queue) |
| { |
| gpointer retval; |
| |
| g_return_val_if_fail (queue, NULL); |
| g_return_val_if_fail (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. |
| * |
| * Try 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. |
| **/ |
| gpointer |
| g_async_queue_try_pop_unlocked (GAsyncQueue* queue) |
| { |
| g_return_val_if_fail (queue, NULL); |
| g_return_val_if_fail (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. |
| * |
| * Pop data from the @queue. If no data is received before @end_time, |
| * #NULL is returned. |
| * |
| * Return value: data from the queue or #NULL, when no data is |
| * received before @end_time. |
| **/ |
| 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 (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. |
| * |
| * Pop 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. |
| * |
| * Return value: data from the queue or #NULL, when no data is |
| * received before @end_time. |
| **/ |
| gpointer |
| g_async_queue_timed_pop_unlocked (GAsyncQueue* queue, GTimeVal *end_time) |
| { |
| g_return_val_if_fail (queue, NULL); |
| g_return_val_if_fail (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. |
| **/ |
| gint |
| g_async_queue_length (GAsyncQueue* queue) |
| { |
| glong retval; |
| |
| g_return_val_if_fail (queue, 0); |
| g_return_val_if_fail (queue->ref_count > 0, 0); |
| |
| g_mutex_lock (queue->mutex); |
| retval = queue->queue->length - queue->waiting_threads; |
| g_mutex_unlock (queue->mutex); |
| |
| return retval; |
| } |
| |
| /** |
| * g_async_queue_length_unlocked: |
| * @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. This function must be called while holding the @queue's |
| * lock. |
| * |
| * Return value: the length of the @queue. |
| **/ |
| gint |
| g_async_queue_length_unlocked (GAsyncQueue* queue) |
| { |
| g_return_val_if_fail (queue, 0); |
| g_return_val_if_fail (queue->ref_count > 0, 0); |
| |
| return queue->queue->length - queue->waiting_threads; |
| } |
| |