pluto: Added a generic event queue.

This allows to easily execute arbitrary callbacks in the context of the pluto
main thread (e.g. in order to synchronize with threads from the thread-pool).

src/pluto/event_queue.h

@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2010 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program 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 General Public License
+ * for more details.
+ */
+
+/**
+ * @defgroup event_queue event_queue
+ * @{ @ingroup pluto
+ */
+
+#ifndef EVENT_QUEUE_H_
+#define EVENT_QUEUE_H_
+
+typedef struct event_queue_t event_queue_t;
+
+/**
+ * The event queue facility can be used to synchronize thread-pool threads
+ * with the pluto main thread.  That is, all queued callbacks are executed
+ * asynchronously by the pluto main thread.
+ */
+struct event_queue_t {
+
+	/**
+	 * Returns the file descriptor used to notify the main thread.
+	 *
+	 * @return				fd to use in the main thread
+	 */
+	int (*get_event_fd) (event_queue_t *this);
+
+	/**
+	 * Handle all queued events.
+	 */
+	void (*handle) (event_queue_t *this);
+
+	/**
+	 * Add an event to the queue.
+	 *
+	 * @param callback		callback function to add to the queue
+	 * @param data			data supplied to the callback function
+	 * @param cleanup		optional cleanup function
+	 */
+	void (*queue) (event_queue_t *this, void (*callback)(void *data),
+				   void *data, void (*cleanup)(void *data));
+
+	/**
+	 * Destroy this instance.
+	 */
+	void (*destroy) (event_queue_t *this);
+
+};
+
+/**
+ * Create the event queue.
+ *
+ * @return					created object
+ */
+event_queue_t *event_queue_create();
+
+#endif /** EVENT_QUEUE_H_ @}*/