internal override void SystemClockChanged(object sender, SystemClockChangedEventArgs args)
{
var target = default(WeakReference <LocalScheduler>);
foreach (var entries in SystemClock.SystemClockChanged)
{
if (entries.TryGetTarget(out var local) && local == this)
{
target = entries;
break;
}
}
SystemClock.SystemClockChanged.Remove(target);
}
/// <summary>
/// Callback invoked when a system clock change is observed in order to adjust and reevaluate
/// the internal scheduling queues.
/// </summary>
/// <param name="args">Currently not used.</param>
/// <param name="sender">Currently not used.</param>
internal void SystemClockChanged(object sender, SystemClockChangedEventArgs args)
{
lock (_gate)
{
lock (s_gate)
{
//
// Best-effort cancellation of short term work. A check for presence in the hash set
// is used to notice race conditions between cancellation and the timer firing (also
// guarded by the same gate object). See checks in ExecuteNextShortTermWorkItem.
//
#if !NO_HASHSET
foreach (var d in _shortTermWork)
#else
foreach (var d in _shortTermWork.Keys)
#endif
{ d.Dispose(); }
_shortTermWork.Clear();
//
// Transition short term work to the long term queue for reevaluation by calling the
// EvaluateLongTermQueue method. We don't know which direction the clock was changed
// in, so we don't optimize for special cases, but always transition the whole queue.
// Notice the short term queue is bounded to SHORTTERM length.
//
while (_shortTerm.Count > 0)
{
var next = _shortTerm.Dequeue();
s_longTerm.Enqueue(next);
}
//
// Reevaluate the queue and don't forget to null out the current timer to force the
// method to create a new timer for the new first long term item.
//
s_nextLongTermWorkItem = null;
EvaluateLongTermQueue(null);
}
}
}
