public void Start <TStateMachine>(ref TStateMachine stateMachine) where TStateMachine : IAsyncStateMachine => AsyncMethodBuilderCore.Start(ref stateMachine);
/// <summary>Associates the builder with the state machine it represents.</summary>
/// <param name="stateMachine">The heap-allocated state machine object.</param>
/// <exception cref="System.ArgumentNullException">The <paramref name="stateMachine"/> argument was null (Nothing in Visual Basic).</exception>
/// <exception cref="System.InvalidOperationException">The builder is incorrectly initialized.</exception>
public void SetStateMachine(IAsyncStateMachine stateMachine)
{
AsyncMethodBuilderCore.SetStateMachine(stateMachine, m_moveNextAction); // argument validation handled by AsyncMethodBuilderCore
}
/// <summary>
/// Outputs a WaitBegin ETW event, and augments the continuation action to output a WaitEnd ETW event.
/// </summary>
/// <param name="task">The task being awaited.</param>
/// <param name="continuation">The action to invoke when the await operation completes.</param>
/// <returns>The action to use as the actual continuation.</returns>
private static Action OutputWaitEtwEvents(Task task, Action continuation)
{
Contract.Requires(task != null, "Need a task to wait on");
Contract.Requires(continuation != null, "Need a continuation to invoke when the wait completes");
if (Task.s_asyncDebuggingEnabled)
{
Task.AddToActiveTasks(task);
}
#if !MONO
var etwLog = TplEtwProvider.Log;
if (etwLog.IsEnabled())
{
// ETW event for Task Wait Begin
var currentTaskAtBegin = Task.InternalCurrent;
// If this task's continuation is another task, get it.
var continuationTask = AsyncMethodBuilderCore.TryGetContinuationTask(continuation);
etwLog.TaskWaitBegin(
(currentTaskAtBegin != null ? currentTaskAtBegin.m_taskScheduler.Id : TaskScheduler.Default.Id),
(currentTaskAtBegin != null ? currentTaskAtBegin.Id : 0),
task.Id, TplEtwProvider.TaskWaitBehavior.Asynchronous,
(continuationTask != null ? continuationTask.Id : 0), System.Threading.Thread.GetDomainID());
}
#endif
// Create a continuation action that outputs the end event and then invokes the user
// provided delegate. This incurs the allocations for the closure/delegate, but only if the event
// is enabled, and in doing so it allows us to pass the awaited task's information into the end event
// in a purely pay-for-play manner (the alternatively would be to increase the size of TaskAwaiter
// just for this ETW purpose, not pay-for-play, since GetResult would need to know whether a real yield occurred).
return(AsyncMethodBuilderCore.CreateContinuationWrapper(continuation, () =>
{
if (Task.s_asyncDebuggingEnabled)
{
Task.RemoveFromActiveTasks(task.Id);
}
#if !MONO
// ETW event for Task Wait End.
Guid prevActivityId = new Guid();
bool bEtwLogEnabled = etwLog.IsEnabled();
if (bEtwLogEnabled)
{
var currentTaskAtEnd = Task.InternalCurrent;
etwLog.TaskWaitEnd(
(currentTaskAtEnd != null ? currentTaskAtEnd.m_taskScheduler.Id : TaskScheduler.Default.Id),
(currentTaskAtEnd != null ? currentTaskAtEnd.Id : 0),
task.Id);
// Ensure the continuation runs under the activity ID of the task that completed for the
// case the antecendent is a promise (in the other cases this is already the case).
if (etwLog.TasksSetActivityIds && (task.Options & (TaskCreationOptions)InternalTaskOptions.PromiseTask) != 0)
{
EventSource.SetCurrentThreadActivityId(TplEtwProvider.CreateGuidForTaskID(task.Id), out prevActivityId);
}
}
#endif
// Invoke the original continuation provided to OnCompleted.
continuation();
#if !MONO
if (bEtwLogEnabled)
{
etwLog.TaskWaitContinuationComplete(task.Id);
if (etwLog.TasksSetActivityIds && (task.Options & (TaskCreationOptions)InternalTaskOptions.PromiseTask) != 0)
{
EventSource.SetCurrentThreadActivityId(prevActivityId);
}
}
#endif
}));
}
/// <summary>Associates the builder with the specified state machine.</summary> /// <param name="stateMachine">The state machine instance to associate with the builder.</param> public void SetStateMachine(IAsyncStateMachine stateMachine) => AsyncMethodBuilderCore.SetStateMachine(stateMachine, task: null);
public void Start <TStateMachine>(ref TStateMachine stateMachine) where TStateMachine : IAsyncStateMachine
{
// Should not be static
AsyncMethodBuilderCore.Start(ref stateMachine);
}
public void Start <TStateMachine>(ref TStateMachine stateMachine) where TStateMachine : IAsyncStateMachine => // will provide the right ExecutionContext semantics AsyncMethodBuilderCore.Start(ref stateMachine);
