public async Task Blocked_Func()
{
// Verify that non-nested function acquistions block.
using (var mutex = new AsyncReentrantMutex())
{
var task1Time = DateTime.MinValue;
var task2Time = DateTime.MinValue;
var task1 = mutex.ExecuteFuncAsync(
async() =>
{
task1Time = DateTime.UtcNow;
await Task.Delay(TimeSpan.FromSeconds(2));
return("TASK1");
});
var task2 = mutex.ExecuteFuncAsync(
async() =>
{
task2Time = DateTime.UtcNow;
await Task.Delay(TimeSpan.FromSeconds(2));
return("TASK2");
});
var result1 = await task1;
var result2 = await task2;
Assert.Equal("TASK1", result1);
Assert.Equal("TASK2", result2);
// So the two tasks above could execute in any order, but only
// one at a time. With the delay, this means that the recorded
// times should be at least 2 seconds apart.
//
// We'll verify at least a 1 second difference to mitigate any
// clock skew.
Assert.True(task1Time > DateTime.MinValue);
Assert.True(task2Time > DateTime.MinValue);
var delta = task1Time - task2Time;
if (delta < TimeSpan.Zero)
{
delta = -delta;
}
Assert.True(delta >= TimeSpan.FromSeconds(1));
}
}
public async Task Nested_Func()
{
// Verify that function reentrancy actually works.
var inner1 = false;
var inner2 = false;
var inner3 = false;
using (var mutex = new AsyncReentrantMutex())
{
var result = await mutex.ExecuteFuncAsync(
async() =>
{
inner1 = true;
return(await mutex.ExecuteFuncAsync(
async() =>
{
inner2 = true;
return await mutex.ExecuteFuncAsync(
async() =>
{
inner3 = true;
return await Task.FromResult("HELLO WORLD!");
});
}));
});
Assert.Equal("HELLO WORLD!", result);
}
Assert.True(inner1);
Assert.True(inner2);
Assert.True(inner3);
}
public async Task Dispose_Func()
{
// Verify that [ObjectDisposedException] is thrown for function tasks waiting
// to acquire the mutex.
var mutex = new AsyncReentrantMutex();
try
{
// Hold the mutex for 2 seconds so the tasks below will block.
var task1Acquired = false;
var task2Acquired = false;
var task3Acquired = false;
var task1 = mutex.ExecuteFuncAsync(
async() =>
{
task1Acquired = true;
await Task.Delay(TimeSpan.FromSeconds(2));
return("TASK1");
});
// Wait for [task1] to actually acquire to mutex.
NeonHelper.WaitFor(() => task1Acquired, defaultTimeout);
// Start two new tasks that will block.
var task2 = mutex.ExecuteFuncAsync(
async() =>
{
task2Acquired = true;
await Task.CompletedTask;
return("TASK2");
});
var task3 = mutex.ExecuteFuncAsync(
async() =>
{
task3Acquired = true;
await Task.CompletedTask;
return("TASK1");
});
// Dispose the mutex. We're expecting [task1] to complete normally and
// [task2] and [task3] to fail with an [OperationCancelledException] with
// their actions never being invoked.
mutex.Dispose();
await Assert.ThrowsAsync <ObjectDisposedException>(async() => await task2);
Assert.False(task2Acquired);
await Assert.ThrowsAsync <ObjectDisposedException>(async() => await task3);
Assert.False(task3Acquired);
await task1;
Assert.True(task1Acquired);
}
finally
{
// Disposing this again shouldn't cause any trouble.
mutex.Dispose();
}
}