/// <summary>
/// Run an asynchronous operation using the current thread as its synchronisation context.
/// </summary>
/// <typeparam name="TResult">
/// The operation result type.
/// </typeparam>
/// <param name="asyncOperation">
/// A <see cref="Func{TResult}" /> delegate representing the asynchronous operation to run.
/// </param>
/// <returns>
/// The operation result.
/// </returns>
public static TResult RunSynchronized <TResult>(Func <Task <TResult> > 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 =>
// ReSharper disable once AccessToDisposedClosure
synchronizationContext.TerminateMessagePump(),
TaskScheduler.Default
);
synchronizationContext.RunMessagePump();
try{
return
(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();
throw; // Never reached.
}
}
}
finally{
SetSynchronizationContext(savedContext);
}
}
/// <summary>
/// Perform Cmdlet post-processing.
/// </summary>
protected sealed override void EndProcessing()
{
ThreadAffinitiveSynchronizationContext.RunSynchronized(EndProcessingAsync);
}
/// <summary>
/// Perform Cmdlet processing.
/// </summary>
protected sealed override void ProcessRecord()
{
ThreadAffinitiveSynchronizationContext.RunSynchronized(ProcessRecordAsync);
}
