netsurf/windows/schedule.c

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/*
* 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 <sys/time.h>
#include <time.h>
#include "utils/log.h"
#include "utils/utils.h"
#include "utils/errors.h"
#include "windows/schedule.h"
#ifdef DEBUG_SCHEDULER
#define SRLOG(x) LOG(x)
#else
#define SRLOG(x)
#endif
/* linked list of scheduled callbacks */
static struct nscallback *schedule_list = NULL;
/**
* scheduled callback.
*/
struct nscallback
{
struct nscallback *next;
struct timeval 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 interface documented in windows/schedule.h */
nserror win32_schedule(int ival, void (*callback)(void *p), void *p)
{
struct nscallback *nscb;
struct timeval tv;
nserror ret;
ret = schedule_remove(callback, p);
if ((ival < 0) || (ret != NSERROR_OK)) {
return ret;
}
tv.tv_sec = ival / 1000; /* miliseconds to seconds */
tv.tv_usec = (ival % 1000) * 1000; /* remainder to microseconds */
nscb = calloc(1, sizeof(struct nscallback));
if (nscb == NULL) {
return NSERROR_NOMEM;
}
SRLOG(("adding callback %p for %p(%p) at %d cs",
nscb, callback, p, ival));
gettimeofday(&nscb->tv, NULL);
timeradd(&nscb->tv, &tv, &nscb->tv);
nscb->callback = callback;
nscb->p = p;
/* add to list front */
nscb->next = schedule_list;
schedule_list = nscb;
return NSERROR_OK;
}
/* exported interface documented in schedule.h */
int
schedule_run(void)
{
struct timeval tv;
struct timeval nexttime;
struct timeval 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;
gettimeofday(&tv, NULL);
while (cur_nscb != NULL) {
if (timercmp(&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;
}
SRLOG(("callback entry %p running %p(%p)",
unlnk_nscb, unlnk_nscb->callback, unlnk_nscb->p));
/* call callback */
unlnk_nscb->callback(unlnk_nscb->p);
free(unlnk_nscb);
/* dispatched events can modify the list,
* instead of locking we simply reset list
* enumeration to the start.
*/
if (schedule_list == NULL)
return -1; /* no more callbacks scheduled */
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 (timercmp(&nexttime, &cur_nscb->tv, >)) {
nexttime = cur_nscb->tv;
}
/* move to next element */
prev_nscb = cur_nscb;
cur_nscb = prev_nscb->next;
}
}
/* make returned time relative to now */
timersub(&nexttime, &tv, &rettime);
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.tv_sec * 1000) + (rettime.tv_usec / 1000);
}
/* exported interface documented in schedule.h */
void list_schedule(void)
{
struct timeval tv;
struct nscallback *cur_nscb;
gettimeofday(&tv, NULL);
LOG(("schedule list at %ld:%ld", tv.tv_sec, tv.tv_usec));
cur_nscb = schedule_list;
while (cur_nscb != NULL) {
LOG(("Schedule %p at %ld:%ld",
cur_nscb, cur_nscb->tv.tv_sec, cur_nscb->tv.tv_usec));
cur_nscb = cur_nscb->next;
}
}
/*
* Local Variables:
* c-basic-offset:8
* End:
*/