public async Task <Result <bool> > SetNext(IMdNode node)
{
if (Next != null)
{
if (Next.XORName.SequenceEqual(node.MdLocator.XORName))
{
return(Result.OK(false)); // no change
}
return(new InvalidOperation <bool>($"Cannot change Next. Current: {Next.XORName}"));
}
else if (!IsFull)
{
return(new InvalidOperation <bool>($"Cannot set Next until node is full (Current count: {Count} of capacity {Constants.MdCapacity}."));
}
var metadata = new MdMetadata
{
Level = this.Level,
Previous = this.Previous,
StartIndex = this.StartIndex,
Next = node.MdLocator
};
// this is not 100% AD
var version = await _dataOps.GetEntryVersionAsync(Constants.METADATA_KEY).ConfigureAwait(false);
await _dataOps.UpdateObjectAsync(Constants.METADATA_KEY, metadata, version).ConfigureAwait(false);
_metadata = metadata;
return(Result.OK(true));
}
public async Task <IMdNode> CreateNewMdNodeAsync(MdMetadata metadata)
{
var mdInfo = await _networkOps.CreateEmptyMd(DataProtocol.DEFAULT_AD_PROTOCOL).ConfigureAwait(false);
var dataOps = new MdDataOps(this, _networkOps, mdInfo);
var newMd = new MdNode(dataOps, _snapshotter);
await newMd.Initialize(metadata).ConfigureAwait(false);
return(newMd);
}
async Task GetOrAddMetadata(MdMetadata metadata = null)
{
var keyCount = await _dataOps.GetKeyCountAsync().ConfigureAwait(false);
if (keyCount > 0)
{
_count = keyCount - 1;
_metadata = await _dataOps.GetValueAsync <MdMetadata>(Constants.METADATA_KEY).ConfigureAwait(false);
return;
}
metadata ??= new MdMetadata();
await _dataOps.AddObjectAsync(Constants.METADATA_KEY, metadata).ConfigureAwait(false);
_metadata = metadata;
}
async Task <Result <Pointer> > ExpandLevelAsync(StoredValue value, ExpectedVersion expectedVersion, IMdNode previous)
{
if (Level == 0)
{
return(new ArgumentOutOfRange <Pointer>(nameof(Level)));
}
byte[] snapshot = default;
if (_snapshotter != null && previous != null)
{
var snapshotResult = await _snapshotter.StoreSnapshot(previous);
if (!snapshotResult.HasValue)
{
return(snapshotResult.CastError <byte[], Pointer>());
}
snapshot = snapshotResult.Value;
}
var meta = new MdMetadata
{
Level = this.Level - 1,
Snapshot = snapshot,
Previous = previous?.MdLocator,
StartIndex = previous?.EndIndex + 1 ?? 0
};
var md = await _dataOps.NodeFactory.CreateNewMdNodeAsync(meta).ConfigureAwait(false);
var leafPointer = await md.TryAppendAsync(value, expectedVersion).ConfigureAwait(false);
if (!leafPointer.HasValue)
{
return(leafPointer);
}
switch (md.Type)
{
case MdType.Pointers: // i.e. we have still not reached the end of the tree
await AddAsync(new Pointer
{
MdLocator = md.MdLocator,
ValueType = typeof(Pointer).Name
}).ConfigureAwait(false);
break;
case MdType.Values: // i.e. we are now right above leaf level
await AddAsync(new Pointer
{
MdLocator = leafPointer.Value.MdLocator,
ValueType = typeof(Pointer).Name
}).ConfigureAwait(false);
break;
default:
return(new ArgumentOutOfRange <Pointer>(nameof(md.Type)));
}
return(leafPointer);
}
public Task Initialize(MdMetadata metadata) => GetOrAddMetadata(metadata);