public async Task LocalMutualExclusion_NoDeadlock()
{
IScope <string> mutex = new LocalMutualExclusion <string>(EqualityComparer <string> .Default);
using (await mutex.WithScopeAsync(KeyOne, CancellationToken.None))
using (await mutex.WithScopeAsync(KeyTwo, CancellationToken.None))
{
}
using (await mutex.WithScopeAsync(KeyTwo, CancellationToken.None))
using (await mutex.WithScopeAsync(KeyOne, CancellationToken.None))
{
}
using (await mutex.WithScopeAsync(KeyOne, CancellationToken.None))
using (await mutex.WithScopeAsync(KeyTwo, CancellationToken.None))
{
}
}
public async Task LocalMutualExclusion_Serializes()
{
IScope <string> mutex = new LocalMutualExclusion <string>(EqualityComparer <string> .Default);
var taskOne = mutex.WithScopeAsync(KeyOne, CancellationToken.None);
var taskTwo = mutex.WithScopeAsync(KeyTwo, CancellationToken.None);
var taskWaiting = mutex.WithScopeAsync(KeyOne, CancellationToken.None);
using (await taskOne)
using (await taskTwo)
{
Assert.IsFalse(taskWaiting.IsCompleted);
}
using (await taskWaiting)
{
}
}
public async Task LocalMutualExclusion_ReferenceCounts()
{
var local = new LocalMutualExclusion <string>(EqualityComparer <string> .Default);
IScope <string> mutex = local;
Action <string, int> AssertReferenceCount = (key, expected) =>
{
int actual;
Assert.IsTrue(local.TryGetReferenceCount(key, out actual));
Assert.AreEqual(expected, actual);
};
var taskA = mutex.WithScopeAsync(KeyOne, CancellationToken.None);
AssertReferenceCount(KeyOne, 1);
var taskB = mutex.WithScopeAsync(KeyOne, CancellationToken.None);
AssertReferenceCount(KeyOne, 2);
using (await taskA)
{
AssertReferenceCount(KeyOne, 2);
Assert.IsFalse(taskB.IsCompleted);
}
AssertReferenceCount(KeyOne, 1);
using (await taskB)
{
AssertReferenceCount(KeyOne, 1);
}
int zero;
Assert.IsFalse(local.TryGetReferenceCount(KeyOne, out zero), "did not clean up per-item semaphore resource");
}
