/**
 * \file
 * <!--
 * This file is part of BeRTOS.
 *
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 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
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 * GNU General Public License for more details.
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 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * As a special exception, you may use this file as part of a free software
 * library without restriction.  Specifically, if other files instantiate
 * templates or use macros or inline functions from this file, or you compile
 * this file and link it with other files to produce an executable, this
 * file does not by itself cause the resulting executable to be covered by
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 * Copyright 2006 Develer S.r.l. (http://www.develer.com/)
 *
 * -->
 *
 * \brief Simple notifier for the observer/subject pattern (implementation)
 *
 * \author Bernie Innocenti <bernie@codewiz.org>
 */

#include "observer.h"
#include <cpu/irq.h>  // IRQ_DISABLE/IRQ_ENABLE


void observer_SetEvent(Observer *observer, void (*event)(int event_id, void *param))
{
	observer->event = event;
}

void observer_InitSubject(Subject *subject)
{
	LIST_INIT(&subject->observers);
}

void observer_Subscribe(Subject *subject, Observer *observer)
{
	ATOMIC(ADDHEAD(&subject->observers, &observer->link));
}

void observer_Unsubscribe(UNUSED_ARG(Subject *,subject), Observer *observer)
{
	ATOMIC(REMOVE(&observer->link));
}

void observer_notify(Subject *subject, int event_id, void *param)
{
	Observer *observer;
	cpu_flags_t irqstate;
	IRQ_SAVE_DISABLE(irqstate);

	/*
	 * Run over list with protection against other
	 * threads, but re-enable irqs in callbacks.
	 */
	FOREACH_NODE(observer, &subject->observers)
	{
		IRQ_RESTORE(irqstate);
		observer->event(event_id, param);
		IRQ_SAVE_DISABLE(irqstate);
	}

	IRQ_RESTORE(irqstate);
}
