public static async Task <Tuple <bool, string> > TryWriteMerkleNodeAsync(this ICampfireNetObjectStore store, string ns, MerkleNode node)
{
using (var ms = new MemoryStream()) {
using (var writer = new BinaryWriter(ms, Encoding.UTF8, true)) {
writer.WriteMerkleNode(node);
}
var objectData = ms.GetBuffer();
var length = (int)ms.Position;
var hash = CampfireNetHash.ComputeSha256Base64(objectData, 0, length);
var isNewlyWritten = await store.TryWriteUniqueAsync(ns, hash, objectData).ConfigureAwait(false);
// var copy = await ReadMerkleNodeAsync(store, ns, hash).ConfigureAwait(false);
// if (copy.TypeTag != node.TypeTag || copy.LeftHash != node.LeftHash || copy.RightHash != node.RightHash || copy.Descendents != node.Descendents) {
// throw new InvalidStateException();
// }
return(Tuple.Create(isNewlyWritten, hash));
}
}
private async Task <string> InsertHelperAsyncUnderTreeLock(string replaceeHash, MerkleNode replaceeNode, string inserteeHash)
{
var rightHash = replaceeNode.RightHash;
var rightNode = await objectStore.ReadMerkleNodeAsync(NetworkDataNamespace, rightHash).ConfigureAwait(false);
var rightwardDescendents = rightNode == null ? 0 : (1 + rightNode.Descendents);
var isReplaceePerfect = replaceeNode.Descendents == rightwardDescendents * 2;
if (isReplaceePerfect)
{
var internalNode = new MerkleNode {
TypeTag = MerkleNodeTypeTag.Node,
LeftHash = replaceeHash,
RightHash = inserteeHash,
Descendents = 2 + replaceeNode.Descendents
};
var internalNodeHash = (await objectStore.TryWriteMerkleNodeAsync(NetworkDataNamespace, internalNode).ConfigureAwait(false)).Item2;
await objectStore.TryWriteUniqueAsync(TreeContainmentNamespace, internalNodeHash, new byte[0]).ConfigureAwait(false);
return(internalNodeHash);
}
var rightReplacementHash = await InsertHelperAsyncUnderTreeLock(rightHash, rightNode, inserteeHash).ConfigureAwait(false);
replaceeNode.Descendents += 2; // leaf and inner node
replaceeNode.RightHash = rightReplacementHash;
var newReplaceeNodeHash = (await objectStore.TryWriteMerkleNodeAsync(NetworkDataNamespace, replaceeNode).ConfigureAwait(false)).Item2;
await objectStore.TryWriteUniqueAsync(TreeContainmentNamespace, newReplaceeNodeHash, new byte[0]).ConfigureAwait(false);
return(newReplaceeNodeHash);
}
