/*

 * Copyright (c) 2009-2012 Niels Provos and Nick Mathewson

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. The name of the author may not be used to endorse or promote products

 *    derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#ifndef _DEFER_INTERNAL_H_

#define _DEFER_INTERNAL_H_

#ifdef __cplusplus

extern "C" {

#endif

#include "event2/event-config.h"

#include <sys/queue.h>

struct deferred_cb;

typedef void (*deferred_cb_fn)(struct deferred_cb *, void *);

/** A deferred_cb is a callback that can be scheduled to run as part of

 * an event_base's event_loop, rather than running immediately. */

struct deferred_cb {

	/** Links to the adjacent active (pending) deferred_cb objects. */

	TAILQ_ENTRY (deferred_cb) cb_next;

	/** True iff this deferred_cb is pending in an event_base. */

	unsigned queued : 1;

	/** The function to execute when the callback runs. */

	deferred_cb_fn cb;

	/** The function's second argument. */

	void *arg;

};

/** A deferred_cb_queue is a list of deferred_cb that we can add to and run. */

struct deferred_cb_queue {

	/** Lock used to protect the queue. */

	void *lock;

	/** How many entries are in the queue? */

	int active_count;

	/** Function called when adding to the queue from another thread. */

	void (*notify_fn)(struct deferred_cb_queue *, void *);

	void *notify_arg;

	/** Deferred callback management: a list of deferred callbacks to

	 * run active the active events. */

	TAILQ_HEAD (deferred_cb_list, deferred_cb) deferred_cb_list;

};

/**

   Initialize an empty, non-pending deferred_cb.

   @param deferred The deferred_cb structure to initialize.

   @param cb The function to run when the deferred_cb executes.

   @param arg The function's second argument.

 */

void event_deferred_cb_init(struct deferred_cb *, deferred_cb_fn, void *);

/**

   Cancel a deferred_cb if it is currently scheduled in an event_base.

 */

void event_deferred_cb_cancel(struct deferred_cb_queue *, struct deferred_cb *);

/**

   Activate a deferred_cb if it is not currently scheduled in an event_base.

 */

void event_deferred_cb_schedule(struct deferred_cb_queue *, struct deferred_cb *);

#define LOCK_DEFERRED_QUEUE(q)						\

	EVLOCK_LOCK((q)->lock, 0)

#define UNLOCK_DEFERRED_QUEUE(q)					\

	EVLOCK_UNLOCK((q)->lock, 0)

#ifdef __cplusplus

}

#endif

void event_deferred_cb_queue_init(struct deferred_cb_queue *);

struct deferred_cb_queue *event_base_get_deferred_cb_queue(struct event_base *);

#endif /* _EVENT_INTERNAL_H_ */