su_timer.c

Sofia SIP is an open-source SIP User-Agent library, compliant with the IETF RFC3261 specification.

 *
 * @param t pointer to the timer object
 */
void su_timer_destroy(su_timer_t *t)
{
  if (t) {
    su_timer_queue_t *timers = su_task_timers(t->sut_task);
    if (timers)
      su_timer_reset0(timers, t);
    su_task_deinit(t->sut_task);
    su_free(NULL, t);
  }
}

/** Set the timer for the given @a interval.
 *
 *  Sets (starts) the given timer to expire after the specified duration.
 *
 * @param t       pointer to the timer object
 * @param wakeup  pointer to the wakeup function
 * @param arg     argument given to the wakeup function
 * @param interval duration in milliseconds before timer wakeup is called
 *
 * @return 0 if successful, -1 otherwise.
 */
int su_timer_set_interval(su_timer_t *t,
			  su_timer_f wakeup,
			  su_timer_arg_t *arg,
			  su_duration_t interval)
{
  su_timer_queue_t *timers = su_timer_tree(t, 0, "su_timer_set_interval");

  if (t == NULL)
    return -1;

  return su_timer_set0(timers, t, wakeup, arg, su_now(), interval);
}

/** Set the timer for the default interval.
 *
 *  Sets (starts) the given timer to expire after the default duration.
 *
 *  The timer must have an default duration.
 *
 * @param t       pointer to the timer object
 * @param wakeup  pointer to the wakeup function
 * @param arg     argument given to the wakeup function
 *
 * @return 0 if successful, -1 otherwise.
 */
int su_timer_set(su_timer_t *t,
		 su_timer_f wakeup,
		 su_timer_arg_t *arg)
{
  su_timer_queue_t *timers = su_timer_tree(t, 1, "su_timer_set");

  if (timers == NULL)
    return -1;

  return su_timer_set0(timers, t, wakeup, arg, su_now(), t->sut_duration);
}

/** Set timer at known time.
 *
 *  Sets the timer to expire at given time.
 *
 * @param t       pointer to the timer object
 * @param wakeup  pointer to the wakeup function
 * @param arg     argument given to the wakeup function
 * @param when    time structure defining the wakeup time
 *
 * @return 0 if successful, -1 otherwise.
 */
int su_timer_set_at(su_timer_t *t,
		    su_timer_f wakeup,
		    su_wakeup_arg_t *arg,
		    su_time_t when)
{
  su_timer_queue_t *timers = su_timer_tree(t, 0, "su_timer_set_at");

  if (timers == NULL)
    return -1;

  return su_timer_set0(timers, t, wakeup, arg, when, 0);
}

/** Set the timer for regular intervals.
 *
 * Run the given timer continuously, call wakeup function repeately in the
 * default interval. If a wakeup call is missed, try to make it up (in other
 * words, this kind of timer fails miserably if time is adjusted and it
 * should really use /proc/uptime instead of gettimeofday()).
 *
 * While a continously running timer is active it @b must @b not @b be @b
 * set using su_timer_set() or su_timer_set_at().
 *
 * The timer must have an non-zero default interval.
 *
 * @param t       pointer to the timer object
 * @param wakeup  pointer to the wakeup function
 * @param arg     argument given to the wakeup function
 *
 * @return 0 if successful, -1 otherwise.
 */
int su_timer_run(su_timer_t *t,
		 su_timer_f wakeup,
		 su_timer_arg_t *arg)
{
  su_timer_queue_t *timers = su_timer_tree(t, 1, "su_timer_run");
  su_time_t now;

  if (timers == NULL)
    return -1;

  t->sut_running = run_at_intervals;
  t->sut_run = now = su_now();
  t->sut_woken = 0;

  return su_timer_set0(timers, t, wakeup, arg, now, t->sut_duration);
}

/**Set the timer for regular intervals.
 *
 * Run the given timer continuously, call wakeup function repeately in the
 * default interval. While a continously running timer is active it @b must
 * @b not @b be @b set using su_timer_set() or su_timer_set_at(). Unlike
 * su_timer_run(), set for ever timer does not try to catchup missed
 * callbacks.
 *
 * The timer must have an non-zero default interval.
 *
 * @param t       pointer to the timer object
 * @param wakeup  pointer to the wakeup function
 * @param arg     argument given to the wakeup function
 *
 * @return 0 if successful, -1 otherwise.
 */
int su_timer_set_for_ever(su_timer_t *t,
			  su_timer_f wakeup,
			  su_timer_arg_t *arg)
{
  su_timer_queue_t *timers = su_timer_tree(t, 1, "su_timer_set_for_ever");
  su_time_t now;

  if (timers == NULL)
    return -1;

  t->sut_running = run_for_ever;
  t->sut_run = now = su_now();
  t->sut_woken = 0;

  return su_timer_set0(timers, t, wakeup, arg, now, t->sut_duration);
}

/**Reset the timer.
 *
 * Resets (stops) the given timer.
 *
 * @param t  pointer to the timer object
 *
 * @return 0 if successful, -1 otherwise.
 */
int su_timer_reset(su_timer_t *t)
{
  su_timer_queue_t *timers = su_timer_tree(t, 0, "su_timer_reset");

  if (timers == NULL)
    return -1;

  return su_timer_reset0(timers, t);
}

/** @internal Check for expired timers in queue.
 *
 * The function su_timer_expire() checks a timer queue and executes and
 * removes expired timers from the queue. It also calculates the time when
 * the next timer expires.
 *
 * @param timers   pointer to the timer queue
 * @param timeout  timeout in milliseconds [IN/OUT]
 * @param now      current timestamp
 *
 * @return
 * The number of expired timers.
 */
int su_timer_expire(su_timer_queue_t * const timers,
		    su_duration_t *timeout,
		    su_time_t now)
{
  su_timer_t *t;
  su_timer_f f;
  int n = 0;

  if (!*timers)
    return n;

  for (;;) {
    t = timers_first(*timers);

    if (t == NULL || SU_TIME_CMP(t->sut_when, now) > 0)
      break;

    timers_remove(timers, t);

    f = t->sut_wakeup; t->sut_wakeup = NULL;
    assert(f);

    if (t->sut_running == run_at_intervals) {
      while (t->sut_running == run_at_intervals &&
	     t->sut_duration > 0) {
	if (su_time_diff(t->sut_when, now) > 0) {
	  su_timer_set0(timers, t, f, t->sut_arg, t->sut_run, 0);
	  break;
	}
	t->sut_when = t->sut_run = su_time_add(t->sut_run, t->sut_duration);
	t->sut_woken++;
	f(su_root_magic(su_task_root(t->sut_task)), t, t->sut_arg), n++;
      }
    }
    else if (t->sut_running == run_for_ever) {
      t->sut_woken++;
      t->sut_when = now;
      f(su_root_magic(su_task_root(t->sut_task)), t, t->sut_arg), n++;
      if (t->sut_running == run_for_ever)
	su_timer_set0(timers, t, f, t->sut_arg, now, t->sut_duration);
    }
    else {
      t->sut_when = now;
      f(su_root_magic(su_task_root(t->sut_task)), t, t->sut_arg); n++;
    }
  }

  if (t) {
    su_duration_t at = su_duration(t->sut_when, now);

    if (at < *timeout)
      *timeout = at;
  }

  return n;
}


/** Calculate duration in milliseconds until next timer expires. */
su_duration_t su_timer_next_expires(su_timer_t const * t, su_time_t now)
{
  su_duration_t tout;

  t = timers_first(t);

  if (!t)
    return SU_DURATION_MAX;

  tout = su_duration(t->sut_when, now);

  return tout > 0 ? tout : 0 ;
}

/**
 * Resets and frees all timers belonging to a task.
 *
 * The function su_timer_destroy_all() resets and frees all timers belonging
 * to the specified task in the queue.
 *
 * @param timers   pointer to the timers
 * @param task     task owning the timers
 *
 * @return Number of timers reset.
 */
int su_timer_reset_all(su_timer_queue_t *timers, su_task_r task)
{
  su_timer_t *t, *t_next;
  int n = 0;

  if (!timers || !*timers)
    return 0;

  for (t = timers_first(*timers); t; t = t_next) {
    t_next = timers_succ(t);

    if (su_task_cmp(task, t->sut_task))
      continue;

    n++;
    timers_remove(timers, t);
    su_free(NULL, t);
  }

  return n;
}

/** Get the root object owning the timer.
 *
 * Return pointer to the root object owning the timer.
 *
 * @param t pointer to the timer
 *
 * @return Pointer to the root object.
 */
su_root_t *su_timer_root(su_timer_t const *t)
{
  return t ? su_task_root(t->sut_task) : NULL;
}