using System.Threading;
using System.Threading.Tasks;
+using System.Runtime.ExceptionServices;
namespace System.Runtime.CompilerServices
{
- public struct TaskAwaiter
+ public struct TaskAwaiter : ICriticalNotifyCompletion
{
readonly Task task;
public void GetResult ()
{
+ if (!task.IsCompleted)
+ task.WaitCore (Timeout.Infinite, CancellationToken.None, true);
+
if (task.Status != TaskStatus.RanToCompletion)
- throw HandleUnexpectedTaskResult (task);
+ // Merge current and dispatched stack traces if there is any
+ ExceptionDispatchInfo.Capture (HandleUnexpectedTaskResult (task)).Throw ();
}
internal static Exception HandleUnexpectedTaskResult (Task task)
{
switch (task.Status) {
case TaskStatus.Canceled:
+ // Use original exception when we have one
+ if (task.ExceptionSlot.Exception != null)
+ goto case TaskStatus.Faulted;
+
return new TaskCanceledException (task);
case TaskStatus.Faulted:
- return task.Exception.InnerException;
+ return task.ExceptionSlot.Exception.InnerException;
default:
- return new InvalidOperationException ("The task has not finished yet");
+ throw new ArgumentException (string.Format ("Unexpected task `{0}' status `{1}'", task.Id, task.Status));
}
}
- internal static void HandleOnCompleted (Task task, Action continuation, bool continueOnSourceContext)
+ internal static void HandleOnCompleted (Task task, Action continuation, bool continueOnSourceContext, bool manageContext)
{
- if (continueOnSourceContext && SynchronizationContext.Current != null)
- task.ContinueWith (l => SynchronizationContext.Current.Post (cont => ((Action) cont) (), continuation), TaskContinuationOptions.ExecuteSynchronously);
- else
- task.ContinueWith ((l, cont) => ((Action) cont) (), continuation, TaskContinuationOptions.ExecuteSynchronously);
+ if (continueOnSourceContext && SynchronizationContext.Current != null && SynchronizationContext.Current.GetType () != typeof (SynchronizationContext)) {
+ task.ContinueWith (new SynchronizationContextContinuation (continuation, SynchronizationContext.Current));
+ } else {
+ IContinuation cont;
+ Task cont_task;
+ if (continueOnSourceContext && !TaskScheduler.IsDefault) {
+ cont_task = new Task (TaskActionInvoker.Create (continuation), null, CancellationToken.None, TaskCreationOptions.None, null);
+ cont_task.SetupScheduler (TaskScheduler.Current);
+ cont = new SchedulerAwaitContinuation (cont_task);
+ } else {
+ cont_task = null;
+ cont = new AwaiterActionContinuation (continuation);
+ }
+
+ //
+ // This is awaiter continuation. For finished tasks we get false result and need to
+ // queue the continuation otherwise the task would block
+ //
+ if (task.ContinueWith (cont, false))
+ return;
+
+ if (cont_task == null) {
+ cont_task = new Task (TaskActionInvoker.Create (continuation), null, CancellationToken.None, TaskCreationOptions.None, null);
+ cont_task.SetupScheduler (TaskScheduler.Current);
+ }
+
+ cont_task.Schedule (true);
+ }
}
public void OnCompleted (Action continuation)
if (continuation == null)
throw new ArgumentNullException ("continuation");
- HandleOnCompleted (task, continuation, true);
+ HandleOnCompleted (task, continuation, true, true);
+ }
+
+ public void UnsafeOnCompleted (Action continuation)
+ {
+ if (continuation == null)
+ throw new ArgumentNullException ("continuation");
+
+ HandleOnCompleted (task, continuation, true, false);
}
}
}