public static System.Threading.Tasks.Task<long> GetStateMachine()
{
Action moveNext = null;
var builder = new AsyncTaskMethodBuilder<long>();
int state = 0;
var taskAwaiter = GetTaskResult().GetAwaiter();
moveNext = () =>
{
switch (state)
{
case 0:
{
if (!taskAwaiter.IsCompleted)
{
state = 1;
taskAwaiter.OnCompleted(moveNext);
}
break;
}
case 1:
{
builder.SetResult(taskAwaiter.GetResult());
break;
}
}
};
moveNext();
return builder.Task;
}
/// <summary>
/// Initializes a new instance of the <see cref="AsyncTaskMethodBuilder"/> struct.
/// </summary>
private AsyncTaskMethodBuilder(TaskController taskManager)
{
this.TaskController = taskManager;
this.MethodBuilder = default;
this.IsCompleted = false;
this.UseBuilder = false;
}
public override Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
{
if (cancellationToken.IsCancellationRequested)
{
return Task.FromCanceled<int>(cancellationToken);
}
_readAtmb = new AsyncTaskMethodBuilder<int>();
Task<int> t = _readAtmb.Task;
_readArgs.SetBuffer(buffer, offset, count);
if (!_socket.ReceiveAsync(_readArgs))
{
ReadCompleted(null, _readArgs);
}
return t;
}
public static IEnumerable<object[]> CanceledTasksAndExpectedCancellationExceptions()
{
var cts = new CancellationTokenSource();
var oce = new OperationCanceledException(cts.Token);
// Scheduled Task
Task<int> generic = Task.Run<int>(new Func<int>(() =>
{
cts.Cancel();
throw oce;
}), cts.Token);
yield return new object[] { LineNumber(), generic, oce };
Task nonGeneric = generic;
// WhenAll Task and Task<int>
yield return new object[] { LineNumber(), Task.WhenAll(generic), oce };
yield return new object[] { LineNumber(), Task.WhenAll(generic, Task.FromResult(42)), oce };
yield return new object[] { LineNumber(), Task.WhenAll(Task.FromResult(42), generic), oce };
yield return new object[] { LineNumber(), Task.WhenAll(generic, generic, generic), oce };
yield return new object[] { LineNumber(), Task.WhenAll(nonGeneric), oce };
yield return new object[] { LineNumber(), Task.WhenAll(nonGeneric, Task.FromResult(42)), oce };
yield return new object[] { LineNumber(), Task.WhenAll(Task.FromResult(42), nonGeneric), oce };
yield return new object[] { LineNumber(), Task.WhenAll(nonGeneric, nonGeneric, nonGeneric), oce };
// Task.Run Task and Task<int> with unwrapping
yield return new object[] { LineNumber(), Task.Run(() => generic), oce };
yield return new object[] { LineNumber(), Task.Run(() => nonGeneric), oce };
// A FromAsync Task and Task<int>
yield return new object[] { LineNumber(), Task.Factory.FromAsync(generic, new Action<IAsyncResult>(ar => { throw oce; })), oce };
yield return new object[] { LineNumber(), Task<int>.Factory.FromAsync(nonGeneric, new Func<IAsyncResult, int>(ar => { throw oce; })), oce };
// AsyncTaskMethodBuilder
var atmb = new AsyncTaskMethodBuilder();
atmb.SetException(oce);
yield return new object[] { LineNumber(), atmb.Task, oce };
}
/// <summary>
/// Initializes a new instance of the <see cref="AsyncTaskMethodBuilder"/> struct.
/// </summary>
private AsyncTaskMethodBuilder(CoyoteRuntime runtime)
{
this.Runtime = runtime;
this.MethodBuilder = default;
}
/// <summary>
/// Initializes a new instance of the <see cref="AsyncTaskMethodBuilder"/> struct.
/// </summary>
private AsyncTaskMethodBuilder(TaskController taskController)
{
this.TaskController = taskController;
this.MethodBuilder = default;
}
public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
{
if (cancellationToken.IsCancellationRequested)
{
return Task.FromCanceled(cancellationToken);
}
_writeAtmb = new AsyncTaskMethodBuilder();
Task t = _writeAtmb.Task;
_writeArgs.SetBuffer(buffer, offset, count);
if (!_socket.SendAsync(_writeArgs))
{
// TODO: #4900 This path should be hit very frequently (sends should very frequently simply
// write into the kernel's send buffer), but it's practically never getting hit due to the current
// System.Net.Sockets.dll implementation that always completing asynchronously on success :(
// If that doesn't get fixed, we should try to come up with some alternative here. This is
// an important path, in part as it means the caller will complete awaits synchronously rather
// than spending the costs associated with yielding in each async method up the call chain.
// (This applies to ReadAsync as well, but typically to a much less extent.)
WriteCompleted(null, _writeArgs);
}
return t;
}
public static void RunAsyncAdditionalBehaviorsTests()
{
{
var atmb = new AsyncTaskMethodBuilder();
var t1 = atmb.Task;
var t2 = atmb.Task;
Assert.True(t1 != null, " > FAILURE. Task should have been initialized.");
Assert.True(t2 != null, " > FAILURE. Task should have been initialized.");
Assert.True(t1 == t2, " > FAILURE. Task should be cached once initialized.");
}
{
var atmb = new AsyncTaskMethodBuilder<int>();
var t1 = atmb.Task;
var t2 = atmb.Task;
Assert.True(t1 != null, " > FAILURE. Task should have been initialized.");
Assert.True(t2 != null, " > FAILURE. Task should have been initialized.");
Assert.True(t1 == t2, " > FAILURE. Task should be cached once initialized.");
}
}
public static void RunAsyncMethodBuilderTests_NegativeTests()
{
// Incorrect usage for AsyncVoidMethodBuilder
{
var atmb = new AsyncTaskMethodBuilder();
Assert.Throws<ArgumentNullException>(
() => { atmb.SetException(null); });
}
// Incorrect usage for AsyncTaskMethodBuilder
{
var avmb = AsyncVoidMethodBuilder.Create();
Assert.Throws<ArgumentNullException>(
() => { avmb.SetException(null); });
}
// Creating a task builder, building it, completing it successfully, and making sure it can't be reset
{
var atmb = AsyncTaskMethodBuilder.Create();
atmb.SetResult();
Assert.Throws<InvalidOperationException>(
() => { atmb.SetResult(); });
Assert.Throws<InvalidOperationException>(
() => { atmb.SetException(new Exception()); });
}
// Incorrect usage for AsyncTaskMethodBuilder<T>
{
var atmb = new AsyncTaskMethodBuilder<int>();
Assert.Throws<ArgumentNullException>(
() => { atmb.SetException(null); });
}
// Creating a task builder <T>, building it, completing it successfully, and making sure it can't be reset
{
var atmb = AsyncTaskMethodBuilder<int>.Create();
atmb.SetResult(43);
Assert.Throws<InvalidOperationException>(
() => { atmb.SetResult(44); });
Assert.Throws<InvalidOperationException>(
() => { atmb.SetException(new Exception()); });
}
}