New File implementing an asynchronous queue to be used for asynchronous

2000-04-28  Sebastian Wilhelmi  <wilhelmi@ira.uka.de>

	* gasyncqueue.c: New File implementing an asynchronous queue to be
	used for asynchronous inter-thread communication.

	* gthreadpool.c: New File implementing a thread pool to be used
	for distributing work among several threads.

	* glib.h: Added the type and function declarations for these two
	types.

	* tests/threadpool-test.c: New File implementing a test for the
	thread pool. This also checks the asynchronous queue underlying
	the thread pool.

	* tests/Makefile.am: Changed accordingly.

gasyncqueue.c

@@ -0,0 +1,276 @@
+/* GLIB - Library of useful routines for C programming
+ * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
+ *
+ * GAsyncQueue: asyncronous 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 Library 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library 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;
+};
+
+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;
+}
+
+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);
+}
+
+void 
+g_async_queue_ref_unlocked (GAsyncQueue *queue)
+{
+  g_return_if_fail (queue);
+  g_return_if_fail (queue->ref_count > 0);
+  
+  queue->ref_count++;
+}
+
+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);
+    }
+}
+
+void 
+g_async_queue_unref (GAsyncQueue *queue)
+{
+  gboolean stop;
+
+  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);
+}
+
+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);
+}
+
+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);
+}
+
+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);
+}
+
+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;
+}
+
+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;
+}
+
+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);
+}
+
+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;
+}
+
+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);
+}
+
+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;  
+}
+
+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);
+}
+
+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;
+}
+
+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;
+}
+