observer.c

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#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);
}