void OnNext()
{
var work_item = (InvocationThrottleWorkItem)null;
lock (Sync)
{
if (CurrentWorkItem != null)
{
Debug.WriteLine($"On Next, Current not null, exit {CurrentWorkItem.Id}");
return;
}
if (PendingWorkItem == null)
{
Debug.WriteLine($"On Next, No Pending, exit");
return;
}
var old_current = CurrentWorkItem;
CurrentWorkItem = PendingWorkItem;
PendingWorkItem = null;
work_item = CurrentWorkItem;
work_item.CancellationTokenSource = new CancellationTokenSource();
}
Debug.WriteLine($"On Next, Task.StartNew");
work_item.Task = Task.Factory.StartNew((_wi) =>
{
var wi = (InvocationThrottleWorkItem)_wi;
var ct = wi.CancellationTokenSource.Token;
bool success = false;
try
{
if (ct.IsCancellationRequested)
{
Debug.WriteLine($"Invoke, canceled before started {wi.Id}");
}
else
{
Debug.WriteLine($"Invoke, {wi.Id}");
wi.Action(wi.State, wi, ct);
Debug.WriteLine($"Invoke success, {wi.Id}");
success = true;
}
}
catch (OperationCanceledException)
{
Debug.WriteLine($"Invoke, canceled {wi.Id}");
}
catch (Exception ex)
{
Debug.WriteLine($"Invoke, exception {wi.Id}");
}
lock (Sync)
{
if (ct.IsCancellationRequested)
success = false;
var utc_now = DateTime.UtcNow;
var old_current = CurrentWorkItem;
CurrentWorkItem = null;
if (success)
wi.CompleteTimeUtc = DateTime.UtcNow;
// check if there is a task pending
if (PendingWorkItem != null)
{
// it is, but within min,
// or last call failed
// reset timer to start from now
if (success && utc_now - PendingWorkItem.RequestWindowTimeUTC < Min)
{
Debug.WriteLine($"Invoke, pending should be triggered by timer, old current: {wi.Id}, pending: {PendingWorkItem.Id}");
// nothing to do here, timer will take care of it
return;
}
else
{
// last call failed
// or success but pending is waiting > min
// make sure to update window, if current failed
if (!success)
{
if (PendingWorkItem.RequestWindowTimeUTC > old_current.RequestWindowTimeUTC)
PendingWorkItem.RequestWindowTimeUTC = old_current.RequestWindowTimeUTC;
// total window past Max waiting period, invoke
if (Max != null && PendingWorkItem.RequestTimeUTC - PendingWorkItem.RequestWindowTimeUTC >= Max)
{
// past Max waiting time, invoke and ensure runs to completion
PendingWorkItem.MustRunToCompletion = true;
}
// invoke pending action immediately, since its been waiting long enough
Debug.WriteLine($"Invoke, Calling On Next, old current: {wi.Id}, pending: {PendingWorkItem.Id}");
OnNext();
return;
}
}
}
else
{
// no work items pending
// nothing else to do here
Debug.WriteLine($"Invoke, no more pending items, do nothing {wi.Id}");
}
}
}, work_item, CancellationToken.None, TaskCreationOptions.None, Scheduler);
}
public void InvokeAsync(Action<object, InvocationThrottleWorkItem, CancellationToken> cancellableActionWithState, object state)
{
if (cancellableActionWithState == null)
throw new ArgumentNullException(nameof(cancellableActionWithState));
var invocation_time = DateTime.UtcNow;
var current_item = CurrentWorkItem;
if (current_item != null && current_item.RequestTimeUTC >= invocation_time)
return;
lock (Sync)
{
var wi = new InvocationThrottleWorkItem();
wi.RequestTimeUTC = invocation_time;
wi.State = state;
wi.Action = cancellableActionWithState;
Debug.WriteLine($"Invoke Async {wi.Id}");
// Pending request alredy exists
if (PendingWorkItem != null)
{
// update window request time (to be able to check for max later)
wi.RequestWindowTimeUTC = PendingWorkItem.RequestWindowTimeUTC;
wi.MustRunToCompletion = PendingWorkItem.MustRunToCompletion;
// total window past Max waiting period, invoke
if (Max != null && invocation_time - wi.RequestWindowTimeUTC >= Max)
{
// past Max waiting time, invoke and ensure runs to completion
wi.MustRunToCompletion = true;
PendingWorkItem = wi;
Debug.WriteLine($"Invoke Async, must run to completion {wi.Id}");
OnNextIfReady();
return;
}
// within min distance of last pending request
if (invocation_time - PendingWorkItem.RequestTimeUTC < Min)
{
PendingWorkItem = wi;
Debug.WriteLine($"Invoke Async, Reset Timer, RequestWindow: {wi.RequestTimeUTC}, req-window: {(wi.RequestTimeUTC - wi.RequestWindowTimeUTC).TotalMilliseconds} ms, {wi.Id}");
ResetMinTimer();
return;
}
else // passed min distance, invoke
{
PendingWorkItem = wi;
Debug.WriteLine($"Invoke Async, passed min distance {wi.Id}");
OnNextIfReady();
return;
}
}
else // there's no pending request
{
wi.RequestWindowTimeUTC = wi.RequestTimeUTC;
PendingWorkItem = wi;
Debug.WriteLine($"Invoke Async, no pending requests {wi.Id}");
OnNextIfReady();
}
}
}
public void Cancel(bool forced = true)
{
lock(Sync)
{
if(CurrentWorkItem != null)
{
if (forced || !CurrentWorkItem.MustRunToCompletion)
{
CurrentWorkItem.CancellationTokenSource.Cancel();
}
}
if (PendingWorkItem != null)
PendingWorkItem = null;
}
}
