/// <summary>
/// Run an asynchronous operation using the current thread as its synchronisation context.
/// </summary>
/// <param name="asyncOperation">
/// A <see cref="Func{TResult}"/> delegate representing the asynchronous operation to run.
/// </param>
public static void RunSynchronized(Func <Task> asyncOperation)
{
if (asyncOperation == null)
{
throw new ArgumentNullException(nameof(asyncOperation));
}
var savedContext = Current;
try {
using (var synchronizationContext = new ThreadAffinitiveSynchronizationContext()) {
SetSynchronizationContext(synchronizationContext);
var rootOperationTask = asyncOperation();
if (rootOperationTask == null)
{
throw new InvalidOperationException("The asynchronous operation delegate cannot return null.");
}
rootOperationTask.ContinueWith(
operationTask =>
synchronizationContext.TerminateMessagePump(),
scheduler:
TaskScheduler.Default
);
synchronizationContext.RunMessagePump();
try {
rootOperationTask
.GetAwaiter()
.GetResult();
}
catch (AggregateException eWaitForTask) // The TPL will almost always wrap an AggregateException around any exception thrown by the async operation.
{
// Is this just a wrapped exception?
var flattenedAggregate = eWaitForTask.Flatten();
if (flattenedAggregate.InnerExceptions.Count != 1)
{
throw; // Nope, genuine aggregate.
}
// Yep, so rethrow (preserving original stack-trace).
ExceptionDispatchInfo
.Capture(
flattenedAggregate
.InnerExceptions[0]
)
.Throw();
}
}
}
finally {
SetSynchronizationContext(savedContext);
}
}
/// <summary>
/// Perform Cmdlet post-processing.
/// </summary>
protected sealed override void EndProcessing()
{
ThreadAffinitiveSynchronizationContext.RunSynchronized(
() => EndProcessingAsync()
);
PowerShellSink.Instance.UnRegister(GetHashCode());
}
/// <summary>
/// Perform Cmdlet pre-processing.
/// </summary>
protected sealed override void BeginProcessing()
{
PowerShellSink.Instance.Register(this);
ThreadAffinitiveSynchronizationContext.RunSynchronized(
() => BeginProcessingAsync()
);
}
/// <summary>
/// Perform Cmdlet processing.
/// </summary>
protected sealed override void ProcessRecord()
{
ThreadAffinitiveSynchronizationContext.RunSynchronized(
() => ProcessRecordAsync()
);
}
