private Task <TResult> ExecuteAsyncContinueWith(Task <TResult> runningTask)
{
if (!runningTask.IsFaulted || _cancellationToken.IsCancellationRequested)
{
return(runningTask);
}
Exception lastError = runningTask.Exception.InnerException;
if (!(_isTransient(lastError)) || lastError is RetryLimitExceededException)
{
// if not transient, return the faulted running task.
return(runningTask);
}
RetryCondition condition = _shouldRetryHandler(_retryCount++, lastError);
if (!condition.RetryAllowed)
{
return(runningTask);
}
TimeSpan delay = condition.DelayBeforeRetry;
// Perform an extra check in the delay interval.
if (delay < TimeSpan.Zero)
{
delay = TimeSpan.Zero;
}
_onRetrying(_retryCount, lastError, delay);
_previousTask = runningTask;
if (delay > TimeSpan.Zero && (_retryCount > 1 || !_fastFirstRetry))
{
return(Task.Delay(delay)
.ContinueWith <Task <TResult> >(ExecuteAsyncImpl, CancellationToken.None,
TaskContinuationOptions.ExecuteSynchronously, TaskScheduler.Default)
.Unwrap());
}
return(ExecuteAsyncImpl(null));
}
public virtual TResult ExecuteAction <TResult>(Func <TResult> func)
{
Guard.ArgumentNotNull(func, "func");
int retryCount = 0;
TimeSpan delay = TimeSpan.Zero;
Exception lastError;
var shouldRetry = this.RetryStrategy.GetShouldRetryHandler();
for (;;)
{
lastError = null;
try
{
return(func());
}
#pragma warning disable 0618
catch (RetryLimitExceededException limitExceededEx)
#pragma warning restore 0618
{
// The user code can throw a RetryLimitExceededException to force the exit from the retry loop.
// The RetryLimitExceeded exception can have an inner exception attached to it. This is the exception
// which we will have to throw up the stack so that callers can handle it.
if (limitExceededEx.InnerException != null)
{
throw limitExceededEx.InnerException;
}
else
{
return(default(TResult));
}
}
catch (Exception ex)
{
lastError = ex;
if (!(this.ErrorDetectionStrategy.IsTransient(lastError)))
{
throw;
}
RetryCondition condition = shouldRetry(retryCount++, lastError);
if (!condition.RetryAllowed)
{
throw;
}
delay = condition.DelayBeforeRetry;
}
// Perform an extra check in the delay interval. Should prevent from accidentally ending up with the
// value of -1 that will block a thread indefinitely. In addition, any other negative numbers will
// cause an ArgumentOutOfRangeException fault that will be thrown by Thread.Sleep.
if (delay.TotalMilliseconds < 0)
{
delay = TimeSpan.Zero;
}
this.OnRetrying(retryCount, lastError, delay);
if (retryCount > 1 || !this.RetryStrategy.FastFirstRetry)
{
Task.Delay(delay).Wait();
}
}
}