protected override async Task <SelectedSnapshot> LoadAsync(string persistenceId,
SnapshotSelectionCriteria criteria)
{
if (criteria.Equals(SnapshotSelectionCriteria.None))
{
return(null);
}
var streamName = GetStreamName(persistenceId);
if (!criteria.Equals(SnapshotSelectionCriteria.Latest))
{
var result = await FindSnapshot(streamName, criteria.MaxSequenceNr, criteria.MaxTimeStamp);
return(result.Snapshot);
}
var slice = await _conn.ReadStreamEventsBackwardAsync(streamName, StreamPosition.End, 1, false);
if (slice == null || slice.Status != SliceReadStatus.Success || !slice.Events.Any())
{
return(null);
}
return(slice.Events.Select(_snapshotAdapter.Adapt).First());
}
protected override async Task DeleteAsync(string persistenceId, SnapshotSelectionCriteria criteria)
{
var streamName = GetStreamName(persistenceId);
var m = await _conn.GetStreamMetadataAsync(streamName);
var streamMetadata = m.StreamMetadata.Copy();
if (criteria.Equals(SnapshotSelectionCriteria.Latest))
{
var slice = await _conn.ReadStreamEventsBackwardAsync(streamName, StreamPosition.End, 1, false);
if (slice.Events.Any())
{
var @event = slice.Events.First();
var highestEventPosition = @event.OriginalEventNumber;
streamMetadata = streamMetadata
.SetTruncateBefore(highestEventPosition);
await _conn.SetStreamMetadataAsync(streamName, ExpectedVersion.Any, streamMetadata.Build());
}
}
else if (!criteria.Equals(SnapshotSelectionCriteria.None))
{
var timestamp = criteria.MaxTimeStamp != DateTime.MinValue ? criteria.MaxTimeStamp : default(DateTime?);
var result = await FindSnapshot(streamName, criteria.MaxSequenceNr, timestamp);
if (result.Snapshot == null)
{
return;
}
streamMetadata = streamMetadata.SetTruncateBefore(result.EventNumber + 1);
await _conn.SetStreamMetadataAsync(streamName, ExpectedVersion.Any, streamMetadata.Build());
}
}
