netsurf/frontends/kolibrios/schedule.c

/*
 * Copyright 2008 Vincent Sanders <vince@simtec.co.uk>
 *
 * This file is part of NetSurf, http://www.netsurf-browser.org/
 *
 * NetSurf 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; version 2 of the License.
 *
 * NetSurf 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, see <http://www.gnu.org/licenses/>.
 */

#include <time.h>
#include <stdlib.h>

#include "utils/sys_time.h"
#include "utils/log.h"
#include <kos32sys.h>
#include "framebuffer/schedule.h"

#ifdef DEBUG_SCHEDULER
#define SRLOG(x...) LOG(x)
#else
#define SRLOG(x...) ((void) 0)
#endif

/* linked list of scheduled callbacks */
static struct nscallback *schedule_list = NULL;

/**
 * scheduled callback.
 */
struct nscallback
{
        struct nscallback *next;
        uint32_t tv;
        void (*callback)(void *p);
        void *p;
};

/**
 * Unschedule a callback.
 *
 * \param  callback  callback function
 * \param  p         user parameter, passed to callback function
 *
 * All scheduled callbacks matching both callback and p are removed.
 */
static nserror schedule_remove(void (*callback)(void *p), void *p)
{
        struct nscallback *cur_nscb;
        struct nscallback *prev_nscb;
        struct nscallback *unlnk_nscb;

	/* check there is something on the list to remove */
        if (schedule_list == NULL) {
                return NSERROR_OK;
	}

	SRLOG("removing %p, %p", callback, p);

        cur_nscb = schedule_list;
        prev_nscb = NULL;

        while (cur_nscb != NULL) {
                if ((cur_nscb->callback ==  callback) &&
                    (cur_nscb->p ==  p)) {
                        /* item to remove */

                        SRLOG("callback entry %p removing  %p(%p)",
                             cur_nscb, cur_nscb->callback, cur_nscb->p);

                        /* remove callback */
                        unlnk_nscb = cur_nscb;
                        cur_nscb = unlnk_nscb->next;

                        if (prev_nscb == NULL) {
                                schedule_list = cur_nscb;
                        } else {
                                prev_nscb->next = cur_nscb;
                        }
                        free (unlnk_nscb);
                } else {
                        /* move to next element */
                        prev_nscb = cur_nscb;
                        cur_nscb = prev_nscb->next;
                }
        }

	return NSERROR_OK;
}

/* exported function documented in framebuffer/schedule.h */
nserror framebuffer_schedule(int tival, void (*callback)(void *p), void *p)
{
	struct nscallback *nscb;
	nserror ret;

	/* ensure uniqueness of the callback and context */
	ret = schedule_remove(callback, p);
	if ((tival < 0) || (ret != NSERROR_OK)) {
		return ret;
	}

	/* LOG("Adding %p(%p) in %d", callback, p, tival); */

	nscb = calloc(1, sizeof(struct nscallback));
    nscb->tv = get_tick_count() + tival / 10;
	nscb->callback = callback;
	nscb->p = p;

    /* add to list front */
    nscb->next = schedule_list;
    schedule_list = nscb;

	return NSERROR_OK;
}

/* exported function documented in framebuffer/schedule.h */
int schedule_run(void)
{
	uint32_t tv;
	uint32_t nexttime;
	uint32_t rettime;
    struct nscallback *cur_nscb;
    struct nscallback *prev_nscb;
    struct nscallback *unlnk_nscb;

    if (schedule_list == NULL)
            return -1;

	/* reset enumeration to the start of the list */
    cur_nscb = schedule_list;
    prev_nscb = NULL;
	nexttime = cur_nscb->tv;

    tv = get_tick_count();

    while (cur_nscb != NULL) {
            if (tv > cur_nscb->tv) {
                    /* scheduled time */

                        /* remove callback */
                        unlnk_nscb = cur_nscb;

                        if (prev_nscb == NULL) {
                                schedule_list = unlnk_nscb->next;
                        } else {
                                prev_nscb->next = unlnk_nscb->next;
                        }

                        unlnk_nscb->callback(unlnk_nscb->p);

                        free(unlnk_nscb);

                        /* need to deal with callback modifying the list. */
			if (schedule_list == NULL)
				return -1; /* no more callbacks scheduled */
			
                        /* reset enumeration to the start of the list */
                        cur_nscb = schedule_list;
                        prev_nscb = NULL;
			nexttime = cur_nscb->tv;
                } else {
			/* if the time to the event is sooner than the
			 * currently recorded soonest event record it 
			 */
                    if (nexttime > cur_nscb->tv) {
                            nexttime = cur_nscb->tv;
                    }
                    /* move to next element */
                    prev_nscb = cur_nscb;
                    cur_nscb = prev_nscb->next;
            }
    }

	/* make rettime relative to now */
    rettime = tv - nexttime;

	/* SRLOG("returning time to next event as %ldms",(rettime.tv_sec * 1000) + (rettime.tv_usec / 1000));  */

	/* return next event time in milliseconds (24days max wait) */
    return rettime * 10;
}

void list_schedule(void)
{
	uint32_t tv;
    struct nscallback *cur_nscb;

    tv = get_tick_count();

    NSLOG(netsurf, DEBUG, "schedule list at %u", tv);

    cur_nscb = schedule_list;

    while (cur_nscb != NULL) {
            NSLOG(netsurf, DEBUG, "Schedule %p at %ld", cur_nscb, cur_nscb->tv);
            cur_nscb = cur_nscb->next;
    }
}


/*
 * Local Variables:
 * c-basic-offset:8
 * End:
 */