private IRunnable PollTask()
{
Contract.Assert(InEventLoop);
IRunnable task;
if (!_taskQueue.TryDequeue(out task))
{
_emptyQueueEvent.Reset();
if (!_taskQueue.TryDequeue(out task) && !IsShuttingDown)
// revisit queue as producer might have put a task in meanwhile
{
var nextScheduledTask = ScheduledTaskQueue.Peek();
if (nextScheduledTask != null)
{
var wakeupTimeout = new TimeSpan(nextScheduledTask.Deadline.When - MonotonicClock.GetTicks());
if (wakeupTimeout.Ticks > 0)
{
if (_emptyQueueEvent.Wait(wakeupTimeout))
{
// woken up before the next scheduled task was due
_taskQueue.TryDequeue(out task);
}
}
}
else
{
_emptyQueueEvent.Wait(); // wait until work is put into the queue
_taskQueue.TryDequeue(out task);
}
}
}
return(task);
}
private bool FetchFromScheduledTaskQueue()
{
if (ScheduledTaskQueue.IsEmpty)
{
return(true);
}
PreciseTimeSpan nanoTime = PreciseTimeSpan.FromStart;
IScheduledRunnable scheduledTask = PollScheduledTask(nanoTime);
while (scheduledTask is object)
{
if (!_taskQueue.TryEnqueue(scheduledTask))
{
// No space left in the task queue add it back to the scheduledTaskQueue so we pick it up again.
_ = ScheduledTaskQueue.TryEnqueue(scheduledTask);
return(false);
}
scheduledTask = PollScheduledTask(nanoTime);
}
return(true);
}
protected bool FetchFromScheduledTaskQueue()
{
if (ScheduledTaskQueue.IsEmpty)
{
return(true);
}
var nanoTime = PreciseTime.NanoTime();
var scheduledTask = PollScheduledTask(nanoTime);
var taskQueue = _taskQueue;
while (scheduledTask is object)
{
if (!taskQueue.TryEnqueue(scheduledTask))
{
// No space left in the task queue add it back to the scheduledTaskQueue so we pick it up again.
_ = ScheduledTaskQueue.TryEnqueue(scheduledTask);
return(false);
}
scheduledTask = PollScheduledTask(nanoTime);
}
return(true);
}