public void RaceConditionBetweenCancellingAndReleasingWaiterFromTheQueue()
{
FifoSemaphore fs = new FifoSemaphore(2);
var cts = new CancellationTokenSource[4];
for (int i = 0; i < cts.Length; i++)
{
cts[i] = new CancellationTokenSource(TimeSpan.FromSeconds(5));
}
try
{
Parallel.For(0, 20, x =>
{
CancellationTokenSource cancellationTokenSource = cts[x % cts.Length];
while (cancellationTokenSource.IsCancellationRequested == false)
{
fs.Acquire(cancellationTokenSource.Token);
try
{
Thread.Sleep(13);
}
finally
{
fs.Release();
}
}
});
}
catch
{
// ignored
}
Assert.True(fs.TryAcquire(TimeSpan.Zero, CancellationToken.None));
try
{
Assert.True(fs.TryAcquire(TimeSpan.Zero, CancellationToken.None));
try
{
}
finally
{
fs.Release();
}
}
finally
{
fs.Release();
}
Assert.Empty(fs._waitQueue);
}
public void ShouldNotLeaveWaitersInQueueIfTimeout()
{
var @lock = new FifoSemaphore(1);
@lock.Acquire(CancellationToken.None);
Assert.False(@lock.TryAcquire(TimeSpan.Zero, CancellationToken.None));
Assert.Empty(@lock._waitQueue);
}
public void ShouldNotLeaveWaitersInQueueIfTimeoutAfterCallingRelease()
{
var @lock = new FifoSemaphore(1);
@lock.Acquire(CancellationToken.None);
try
{
Assert.False(@lock.TryAcquire(TimeSpan.Zero, CancellationToken.None));
Assert.Equal(1, @lock._waitQueue.Count);
Assert.True(@lock._waitQueue.First().IsTimedOut);
}
finally
{
@lock.Release();
}
Assert.Empty(@lock._waitQueue);
}