/* This file is part of Ingen.
 * Copyright (C) 2007 Dave Robillard <http://drobilla.net>
 * 
 * Ingen 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.
 * 
 * Ingen 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 details.
 * 
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifndef QUEUEDEVENT_H
#define QUEUEDEVENT_H

#include "Event.h"

namespace Ingen {

class QueuedEventSource;


/** An Event with a not-time-critical preprocessing stage.
 *
 * These events are events that aren't able to be executed immediately by the
 * Jack thread (because they allocate memory or whatever).  They are pushed
 * on to the QueuedEventQueue where they are preprocessed then pushed on
 * to the realtime Event Queue when they are ready.
 *
 * Lookups for these events should go in the pre_process() method, since they are
 * not time critical and shouldn't waste time in the audio thread doing
 * lookups they can do beforehand.  (This applies for any expensive operation that
 * could be done before the execute() method).
 *
 * \ingroup engine
 */
class QueuedEvent : public Event
{
public:
	/** Process this event into a realtime-suitable event.
	 */
	virtual void pre_process() {
		assert(ThreadManager::current_thread_id() == THREAD_PRE_PROCESS);
		assert(_pre_processed == false);
		_pre_processed = true;
	}

	virtual void execute(SampleCount nframes, FrameTime start, FrameTime end) {
		assert(_pre_processed);
		assert(_time <= end);

		// Didn't prepare in time.  QueuedEvents aren't (necessarily) sample accurate
		// so just run at the beginning of this cycle
		if (_time <= start)
			_time = start;
			
		Event::execute(nframes, start, end);
	}

	virtual void post_process() {}

	/** If this event blocks the prepare phase of other slow events */
	bool is_blocking() { return _blocking; }

	bool is_prepared() { return _pre_processed; }
	
protected:
	QueuedEvent(Engine&                      engine,
	            SharedPtr<Shared::Responder> responder,
	            FrameTime                    time, 
	            bool                         blocking = false,
	            QueuedEventSource*           source = NULL)
	: Event(engine, responder, time)
	, _pre_processed(false), _blocking(blocking), _source(source)
	{
		if (blocking)
			assert(_source);
	}
	
	// NULL event base (for internal events only!)
	QueuedEvent(Engine& engine)
	: Event(engine, SharedPtr<Shared::Responder>(), 0)
	, _pre_processed(false), _blocking(false), _source(NULL)
	{}

	bool               _pre_processed;
	bool               _blocking;
	QueuedEventSource* _source;
};


} // namespace Ingen

#endif // QUEUEDEVENT_H