public async Task <IStreamCollection> GetOrAddCollectionAsync(IValueAD dataDbRoot)
{
IMdNode typeStoreHead;
var typeStoreResult = await dataDbRoot.GetValueAsync().ConfigureAwait(false);
if (!typeStoreResult.HasValue)
{
typeStoreHead = await _nodeFactory.CreateNewMdNodeAsync(null)
.ConfigureAwait(false);
await dataDbRoot.SetAsync(new StoredValue(typeStoreHead.MdLocator))
.ConfigureAwait(false);
}
else
{
var typeStoreHeadLocation = typeStoreResult.Value.Parse <MdLocator>();
typeStoreHead = (await _nodeFactory.LocateAsync(typeStoreHeadLocation)
.ConfigureAwait(false)).Value;
}
Task OnHeadChange(MdLocator newLocation) => dataDbRoot.SetAsync(new StoredValue(newLocation));
var dataRoot = new DataTree(typeStoreHead, OnHeadChange);
return(new StreamCollection(dataRoot, _dataTreeFactory));
}
internal Task <IMdNode> CreateNodeAsync() => _nodeFactory.CreateNewMdNodeAsync(null);