public async Task ExecuteAsync(OperationContext context, CancellationToken cancellationToken)
{
var result = default(TResult);
var executedSuccessfully = false;
OperationError error;
do
{
error = null;
try
{
cancellationToken.ThrowIfCancellationRequested();
if (Condition == null || await Condition.CheckAsync(context, cancellationToken))
{
cancellationToken.ThrowIfCancellationRequested();
result = await _expression(cancellationToken).NotNull();
cancellationToken.ThrowIfCancellationRequested();
executedSuccessfully = true;
}
else
{
throw new OperationCanceledException(CancellationToken.None);
}
}
catch (OperationCanceledException ex)
{
var cancelTask = CancelHandler(ex.CancellationToken).NotNull();
OnRequestHideNotification(new HideNotificationEventArgs(OperationCallback.Cancel));
await cancelTask;
}
catch (Exception ex)
{
error = new OperationError(ex);
var errorHandler = GetErrorHandler(ex);
var errorTask = errorHandler(error, cancellationToken).NotNull();
OnRequestHideNotification(new HideNotificationEventArgs(OperationCallback.Error));
await errorTask;
if (!error.Handled)
{
throw;
}
}
}while (error?.RetryOperation ?? false);
if (executedSuccessfully)
{
var successTask = SuccessHandler(result, cancellationToken).NotNull();
OnRequestHideNotification(new HideNotificationEventArgs(OperationCallback.Success));
await successTask;
}
}
internal async Task ExecuteAsync([NotNull] IOperation operation, CancellationToken cancellationToken)
{
var notificationCancellationTokenSource = operation.Notification?.CancellationTokenSource;
var linkedCancellationTokenSource = CancellationTokenSource.CreateLinkedTokenSource(
notificationCancellationTokenSource?.Token ?? CancellationToken.None,
cancellationToken);
var linkedCancellationToken = linkedCancellationTokenSource.Token;
try
{
OperationError error;
do
{
error = null;
var operationTask = operation.ExecuteAsync(this, linkedCancellationToken);
var notificationMinDurationTask = Task.CompletedTask;
if (operation.Notification != null)
{
var notificationDelayTask = operation.Notification.GetDelayTask();
var completedTask = await Task.WhenAny(operationTask, notificationDelayTask).NotNull();
if (completedTask != operationTask)
{
operation.HideNotificationRequested += Operation_HideNotificationRequested;
RequestShowNotification(operation.Notification);
notificationMinDurationTask = operation.Notification.GetMinDurationTask();
}
}
try
{
await Task.WhenAll(operationTask, notificationMinDurationTask).NotNull();
}
catch (Exception ex)
{
error = new OperationError(ex);
await OnErrorAsync(error);
if (!error.Handled)
{
throw;
}
}
}while (error?.RetryOperation ?? false);
}
finally
{
notificationCancellationTokenSource?.Dispose();
linkedCancellationTokenSource.Dispose();
}
}
public async Task <IOperationErrorResult> HandleAsync(OperationContext context, Exception ex, CancellationToken cancellationToken)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
if (ex == null)
{
throw new ArgumentNullException(nameof(ex));
}
var error = new OperationError <TException>((TException)ex);
await _handler(context, error, cancellationToken).NotNull();
return(error);
}
protected virtual Task OnErrorAsync([NotNull] OperationError error)
{
return(Task.CompletedTask);
}