private static Task <IList <PSObject> > InvokeAsync(this PowerShell ps, CancellationToken cancellationToken)
{
CancellationTokenRegistration ctr;
if (cancellationToken.CanBeCanceled)
{
if (cancellationToken.IsCancellationRequested)
{
return(cancellationToken.AsCanceledTask <IList <PSObject> >());
}
ctr = cancellationToken.Register(p => { ((PowerShell)p).BeginStop((ar) => { }, null); }, ps);
}
else
{
ctr = new CancellationTokenRegistration();
}
var taskFactory = new TaskFactory <IList <PSObject> >(cancellationToken);
var task = taskFactory.FromAsync((callback, state) => ps.BeginInvoke <object>(null, null, callback, state), ps.EndInvoke, null);
task.ContinueWith((antecedent) => { try { ctr.Dispose(); } catch { } });
return(task);
}
/// <summary>
/// Starts the associated process with a cancellation token as an asynchronous operation.
/// </summary>
/// <param name="cancellationToken">A cancellation token that can be used to cancel the process.</param>
/// <returns>The task object representing the asynchronous operation.</returns>
public Task <int> ExecuteAsync(CancellationToken cancellationToken)
{
if (_started)
{
throw new InvalidOperationException();
}
_workingTaskCompletionSource = new TaskCompletionSource <int>();
CancellationTokenRegistration ctr;
if (cancellationToken.CanBeCanceled)
{
if (cancellationToken.IsCancellationRequested)
{
return(cancellationToken.AsCanceledTask <int>(_workingTaskCompletionSource));
}
ctr = cancellationToken.Register(() =>
{
lock (_process)
{
if (_started)
{
_process.Kill();
}
_canceled = true;
}
});
}
else
{
ctr = new CancellationTokenRegistration();
}
if (!_process.EnableRaisingEvents)
{
_process.EnableRaisingEvents = true;
_process.Exited += OnProcess_Exited;
}
_workingTaskCompletionSource.Task.ContinueWith((antecedent) => { try { ctr.Dispose(); } catch { } });
lock (_process)
{
if (_canceled)
{
_workingTaskCompletionSource.TrySetCanceled(/*cancellationToken*/);
}
else
{
StartProcess();
}
}
return(_workingTaskCompletionSource.Task);
}