private ClientMessage.ReadAllEventsBackwardCompleted ReadAllEventsBackward(ClientMessage.ReadAllEventsBackward msg)
{
using (HistogramService.Measure(_readerAllRangeHistogram))
{
var pos = new TFPos(msg.CommitPosition, msg.PreparePosition);
var lastCommitPosition = _readIndex.LastReplicatedPosition;
try
{
if (msg.MaxCount > MaxPageSize)
{
throw new ArgumentException(string.Format("Read size too big, should be less than {0} items",
MaxPageSize));
}
if (pos == TFPos.HeadOfTf)
{
var checkpoint = _writerCheckpoint.Read();
pos = new TFPos(checkpoint, checkpoint);
}
if (pos.CommitPosition < 0 || pos.PreparePosition < 0)
{
return(NoData(msg, ReadAllResult.Error, pos, lastCommitPosition, "Invalid position."));
}
if (msg.ValidationTfLastCommitPosition == lastCommitPosition)
{
return(NoData(msg, ReadAllResult.NotModified, pos, lastCommitPosition));
}
var access = _readIndex.CheckStreamAccess(SystemStreams.AllStream, StreamAccessType.Read, msg.User);
if (!access.Granted)
{
return(NoData(msg, ReadAllResult.AccessDenied, pos, lastCommitPosition));
}
var res = _readIndex.ReadAllEventsBackward(pos, msg.MaxCount);
var resolved = ResolveReadAllResult(res.Records, msg.ResolveLinkTos, msg.User);
if (resolved == null)
{
return(NoData(msg, ReadAllResult.AccessDenied, pos, lastCommitPosition));
}
var metadata = _readIndex.GetStreamMetadata(SystemStreams.AllStream);
return(new ClientMessage.ReadAllEventsBackwardCompleted(
msg.CorrelationId, ReadAllResult.Success, null, resolved, metadata, access.Public, msg.MaxCount,
res.CurrentPos, res.NextPos, res.PrevPos, lastCommitPosition));
}
catch (Exception exc)
{
Log.ErrorException(exc, "Error during processing ReadAllEventsBackward request.");
return(NoData(msg, ReadAllResult.Error, pos, lastCommitPosition, exc.Message));
}
}
}
void IHandle <ClientMessage.ReadAllEventsBackward> .Handle(ClientMessage.ReadAllEventsBackward message)
{
var pos = new TFPos(message.CommitPosition, message.PreparePosition);
if (pos == new TFPos(-1, -1))
{
var checkpoint = _writerCheckpoint.Read();
pos = new TFPos(checkpoint, checkpoint);
}
var result = _readIndex.ReadAllEventsBackward(pos, message.MaxCount, message.ResolveLinks);
message.Envelope.ReplyWith(new ClientMessage.ReadAllEventsBackwardCompleted(message.CorrelationId, result));
}
private ClientMessage.ReadAllEventsBackwardCompleted ReadAllEventsBackward(ClientMessage.ReadAllEventsBackward msg)
{
var pos = new TFPos(msg.CommitPosition, msg.PreparePosition);
try
{
if (pos == TFPos.HeadOfTf)
{
var checkpoint = _writerCheckpoint.Read();
pos = new TFPos(checkpoint, checkpoint);
}
if (pos.CommitPosition < 0 || pos.PreparePosition < 0)
{
return(NoData(msg, ReadAllResult.Error, pos, "Invalid position."));
}
if (msg.ValidationTfEofPosition.HasValue && _readIndex.LastCommitPosition == msg.ValidationTfEofPosition.Value)
{
return(NoData(msg, ReadAllResult.NotModified, pos));
}
var access = _readIndex.CheckStreamAccess(SystemStreams.AllStream, StreamAccessType.Read, msg.User);
if (!access.Granted)
{
return(NoData(msg, ReadAllResult.AccessDenied, pos));
}
var res = _readIndex.ReadAllEventsBackward(pos, msg.MaxCount);
var resolved = ResolveReadAllResult(res.Records, msg.ResolveLinkTos, msg.User);
if (resolved == null)
{
return(NoData(msg, ReadAllResult.AccessDenied, pos));
}
return(new ClientMessage.ReadAllEventsBackwardCompleted(
msg.CorrelationId, ReadAllResult.Success, null, resolved, res.Metadata, access.Public, msg.MaxCount,
res.CurrentPos, res.NextPos, res.PrevPos, res.TfEofPosition));
}
catch (Exception exc)
{
Log.ErrorException(exc, "Error during processing ReadAllEventsBackward request.");
return(NoData(msg, ReadAllResult.Error, pos, exc.Message));
}
}
public IndexReadAllResult ReadAllEventsBackward(TFPos pos, int maxCount) => _readIndex.ReadAllEventsBackward(pos, maxCount);
