/**
* As tor_gettimeofday_cached, but can never move backwards in time.
*
* The returned value may diverge from wall-clock time, since wall-clock time
* can trivially be adjusted backwards, and this can't. Don't mix wall-clock
* time with these values in the same calculation.
*
* Depending on implementation, this function may or may not "smooth out" huge
* jumps forward in wall-clock time. It may or may not keep its results
* advancing forward (as opposed to stalling) if the wall-clock time goes
* backwards. The current implementation does neither of of these.
*
* This function is not thread-safe; do not call it outside the main thread.
*
* In future versions of Tor, this may return a time does not have its
* origin at the Unix epoch.
*/
void
tor_gettimeofday_cached_monotonic(struct timeval *tv)
{
struct timeval last_tv = { 0, 0 };
tor_gettimeofday_cached(tv);
if (timercmp(tv, &last_tv, OP_LT)) {
memcpy(tv, &last_tv, sizeof(struct timeval));
} else {
memcpy(&last_tv, tv, sizeof(struct timeval));
}
}
/**
* Process scheduled callbacks up to current time.
*
* @return The number of milliseconds untill the next scheduled event
* or -1 for no event.
*/
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, 0)) {
/* 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 (timercmp(&nexttime, &cur_nscb->tv, 0)) {
nexttime = cur_nscb->tv;
}
/* move to next element */
prev_nscb = cur_nscb;
cur_nscb = prev_nscb->next;
}
}
/* make rettime relative to now */
timersub(&nexttime, &tv, &rettime);
/*LOG(("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);
}
