private async Task <DispatchingResult> Dispatch(ProjectionDescriptor descriptor, List <MessageEnvelope> envelopes, CancellationToken token)
{
if (descriptor.IsDropped())
{
return(DispatchingResult.StillDropped(descriptor));
}
var sw = new Stopwatch();
var context = new ProjectingContext(MaxProjectingRetries, descriptor.Checkpoint.Position);
var anyDispatched = false;
try
{
sw.Start();
using (var scope = this.NewTransactionScope())
{
foreach (var envelope in envelopes)
{
if (!descriptor.CanDispatch(envelope.Message.GetType(), envelope.Meta.MessagePosition))
{
continue;
}
context.Reset();
if (await DispatchProjection(descriptor, envelope, context).NotOnCapturedContext())
{
descriptor.Checkpoint.Position = envelope.Meta.MessagePosition;
anyDispatched = true;
}
}
await UpdateCheckpoint(descriptor.Checkpoint, descriptor.UndropRequested, token).NotOnCapturedContext();
scope.Complete();
}
sw.Stop();
return(DispatchingResult.Dispatched(descriptor, envelopes.Count, sw.ElapsedMilliseconds, anyDispatched));
}
catch (Exception e) // error in batch
{
sw.Stop();
descriptor.Checkpoint.Position = context.StartingBatchAtPosition; // restoring position
await UpdateCheckpoint(descriptor.Checkpoint, descriptor.UndropRequested, token).NotOnCapturedContext();
return(DispatchingResult.DroppedOnException(descriptor, envelopes.Count, sw.ElapsedMilliseconds, e));
}
}
