glib/libglib/src/gasyncqueue.c
changeset 0 e4d67989cc36
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/glib/libglib/src/gasyncqueue.c	Tue Feb 02 02:01:42 2010 +0200
@@ -0,0 +1,651 @@
+/* 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);
+  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.
+ **/
+EXPORT_C gint
+g_async_queue_length_unlocked (GAsyncQueue* queue)
+{
+  g_return_val_if_fail (queue, 0);
+  g_return_val_if_fail (g_atomic_int_get (&queue->ref_count) > 0, 0);
+
+  return queue->queue->length - queue->waiting_threads;
+}
+
+/**
+ * g_async_queue_sort:
+ * @queue: a #GAsyncQueue
+ * @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
+ *
+ * Sorts @queue using @func. 
+ *
+ * This function will lock @queue before it sorts the queue and unlock
+ * it when it is finished.
+ *
+ * If you were sorting a list of priority numbers to make sure the
+ * lowest priority would be at the top of the queue, you could use:
+ * <informalexample><programlisting> 
+ *  gint32 id1;
+ *  gint32 id2;
+ *   
+ *  id1 = GPOINTER_TO_INT (element1);
+ *  id2 = GPOINTER_TO_INT (element2);
+ *   
+ *  return (id1 > id2 ? +1 : id1 == id2 ? 0 : -1);
+ * </programlisting></informalexample>
+ *
+ * Since: 2.10
+ **/
+EXPORT_C void
+g_async_queue_sort (GAsyncQueue      *queue,
+		    GCompareDataFunc  func,
+		    gpointer          user_data)
+{
+  g_return_if_fail (queue != NULL);
+  g_return_if_fail (func != NULL);
+
+  g_mutex_lock (queue->mutex);
+  g_async_queue_sort_unlocked (queue, func, user_data);
+  g_mutex_unlock (queue->mutex);
+}
+
+/**
+ * g_async_queue_sort_unlocked:
+ * @queue: a #GAsyncQueue
+ * @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
+ *
+ * Sorts @queue using @func. 
+ *
+ * This function is called while holding the @queue's lock.
+ * 
+ * Since: 2.10
+ **/
+EXPORT_C void
+g_async_queue_sort_unlocked (GAsyncQueue      *queue,
+			     GCompareDataFunc  func,
+			     gpointer          user_data)
+{
+  SortData sd;
+
+  g_return_if_fail (queue != NULL);
+  g_return_if_fail (func != NULL);
+
+  sd.func = func;
+  sd.user_data = user_data;
+
+  g_queue_sort (queue->queue, 
+		(GCompareDataFunc)g_async_queue_invert_compare, 
+		&sd);
+}
+
+/*
+ * Private API
+ */
+
+GMutex*
+_g_async_queue_get_mutex (GAsyncQueue* queue)
+{
+  g_return_val_if_fail (queue, NULL);
+  g_return_val_if_fail (g_atomic_int_get (&queue->ref_count) > 0, NULL);
+
+  return queue->mutex;
+}
+
+#define __G_ASYNCQUEUE_C__
+#include "galiasdef.c"