Update TestScheduler.cs #5011
Update TestScheduler.cs #5011
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| @@ -88,10 +88,14 @@ public void AdvanceTo(DateTimeOffset when) | |||
| { | |||
| var scheduledTime = _now.Add(initialDelay ?? delay).UtcTicks; | |||
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| if (!_scheduledWork.TryGetValue(scheduledTime, out var tickItems)) | |||
| ConcurrentQueue<ScheduledItem> tickItems; | |||
| while (!_scheduledWork.TryGetValue(scheduledTime, out tickItems)) | |||
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so this is compare-and-swap basically @brah-mcdude ?
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Ah ok, I think I get this now after reading the original issue on #5010
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tickItems is a queue of all the items that we want to schedule for a specific scheduledTime tick.
We need to extract this queue from the dictionary of all _scheduledWork.
If TryGetValue fails, then we need to create tickItems and add it to _scheduledWork.
However, if by the time that we call TryAdd, someone else has already added a new tickItems at the scheduledTime tick entry, our call to TryAdd will fail. In such a scenario - we need to start over.
In other words, we need to loop while TryGetValue fails.
Actually, our thread's SECOND attempt to TryAdd MUST ALWAYS succeed.
So, theoretically, we could re-write it as a 3 iterations for loop: (int i = 0; i < 3; i++) that will throw an exception if i reaches 2.
fixed bug #5010