public CheckpointProjection(
IStatefulProjection inner,
CheckpointStore checkpointStore,
Action <AllStreamPosition> notifyCheckpoint = null)
{
_inner = inner;
_checkpointStore = checkpointStore;
_notifyCheckpoint = notifyCheckpoint;
_lastCheckpoint = _checkpointStore.Read();
_notifyCheckpoint?.Invoke(AllStreamPosition.FromNullableInt64(_lastCheckpoint));
}
public async Task Project(Envelope message, CancellationToken cancellationToken = default(CancellationToken))
{
var checkpoint = message.Checkpoint;
if (_lastCheckpoint == null || checkpoint > _lastCheckpoint)
{
await _inner.Project(message, cancellationToken).ConfigureAwait(false);
_lastCheckpoint = checkpoint;
_notifyCheckpoint?.Invoke(AllStreamPosition.FromNullableInt64(_lastCheckpoint));
}
}
public AllStreamPosition ReadCheckpoint(string name) =>
_checkpointStores.TryGetValue(name, out CheckpointStore store)
? AllStreamPosition.FromNullableInt64(store.Read())
: AllStreamPosition.None;
