work.c

/*
 * Twin - A Tiny Window System
 * Copyright (c) 2004 Keith Packard <keithp@keithp.com>
 * All rights reserved.
 */

#include <stdlib.h>

#include "twin_private.h"

static twin_queue_t *head;

static twin_order_t _twin_work_order(twin_queue_t *a, twin_queue_t *b)
{
    const twin_work_t *aw = (twin_work_t *) a, *bw = (twin_work_t *) b;

    if (aw->priority < bw->priority)
        return TWIN_BEFORE;
    if (aw->priority > bw->priority)
        return TWIN_AFTER;
    return TWIN_AT;
}

static void _twin_queue_work(twin_work_t *work)
{
    _twin_queue_insert(&head, _twin_work_order, &work->queue);
}

void _twin_run_work(void)
{
    twin_work_t *work;
    twin_work_t *first;

    first = (twin_work_t *) _twin_queue_set_order(&head);
    for (work = first; work; work = (twin_work_t *) work->queue.order)
        if (!(*work->proc)(work->closure))
            _twin_queue_delete(&head, &work->queue);
    _twin_queue_review_order(&first->queue);
}

twin_work_t *twin_set_work(twin_work_proc_t work_proc,
                           int priority,
                           void *closure)
{
    twin_work_t *work = malloc(sizeof(twin_work_t));
    if (!work)
        return NULL;

    work->proc = work_proc;
    work->priority = priority;
    work->closure = closure;
    _twin_queue_work(work);
    return work;
}

void twin_clear_work(twin_work_t *work)
{
    _twin_queue_delete(&head, &work->queue);
}