/*
    Copyright (C) 2000-2009 Paul Davis

    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.

    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.

    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., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#ifndef __ardour_butler_h__
#define __ardour_butler_h__

#include <pthread.h>

#include <glibmm/threads.h>

#ifdef PLATFORM_WINDOWS
#include "pbd/glib_semaphore.h"
#endif

#include "pbd/ringbuffer.h"
#include "pbd/pool.h"
#include "ardour/libardour_visibility.h"
#include "ardour/types.h"
#include "ardour/session_handle.h"



namespace ARDOUR {

/**
 *  One of the Butler's functions is to clean up (ie delete) unused CrossThreadPools.
 *  When a thread with a CrossThreadPool terminates, its CTP is added to pool_trash.
 *  When the Butler thread wakes up, we check this trash buffer for CTPs, and if they
 *  are empty they are deleted.
 */

class LIBARDOUR_API Butler : public SessionHandleRef
{
  public:
	Butler (Session& session);
	~Butler();

	int  start_thread();
	void terminate_thread();
	void schedule_transport_work();
	void summon();
	void stop();
	void wait_until_finished();
	bool transport_work_requested() const;
	void drop_references ();

	framecnt_t audio_diskstream_capture_buffer_size() const { return audio_dstream_capture_buffer_size; }
	framecnt_t audio_diskstream_playback_buffer_size() const { return audio_dstream_playback_buffer_size; }
	uint32_t midi_diskstream_buffer_size()  const { return midi_dstream_buffer_size; }

	static void* _thread_work(void *arg);
	void*         thread_work();

	struct Request {
		enum Type {
			Run,
			Pause,
			Quit
		};
	};

	pthread_t    thread;
	bool         have_thread;
	Glib::Threads::Mutex  request_lock;
        Glib::Threads::Cond   paused;
	bool         should_run;
	mutable gint should_do_transport_work;
	framecnt_t   audio_dstream_capture_buffer_size;
	framecnt_t   audio_dstream_playback_buffer_size;
	uint32_t     midi_dstream_buffer_size;
	RingBuffer<CrossThreadPool*> pool_trash;

#ifdef PLATFORM_WINDOWS
	PBD::atomic_counter m_request_state;
	PBD::GlibSemaphore   m_request_sem;
#else
	int          request_pipe[2];
#endif

private:
	void empty_pool_trash ();
	void config_changed (std::string);

#ifndef PLATFORM_WINDOWS
	int setup_request_pipe ();
#endif

	/**
	 * return true if there are requests to be processed
	 */
	bool wait_for_requests ();

	/**
	 * Remove request from butler request queue
	 *
	 * return true if there was another request and req is valid
	 */
	bool dequeue_request (Request::Type& req);

	/**
	 * Add request to butler thread request queue
	 */
	void queue_request (Request::Type r);

};

} // namespace ARDOUR

#endif // __ardour_butler_h__
