private ulong ModifyInternalNode(ulong id, InternalNode node, byte h, ulong value, byte[]?valueHash)
{
if (value == 0 && node.GetChildByHash(h) != 0 && node.Children.Count() == 2)
{
// we have to handle case when one of two children is deleted and internal node is folded to leaf
var secondChild = node.Children.First(child => child != node.GetChildByHash(h));
// fold only if secondChild is also a leaf
if (GetNodeById(secondChild).Type == NodeType.Leaf)
{
return(secondChild);
}
}
if (value != 0 && node.GetChildByHash(h) != 0 && node.Children.Count() == 1 && GetNodeById(value).Type == NodeType.Leaf)
{
return(value);
}
var modified = InternalNode.ModifyChildren(
node, h, value,
node.Children.Select(id => GetNodeById(id)?.Hash ?? throw new InvalidOperationException()),
valueHash
);
if (modified == null)
{
return(0u);
}
var newId = _versionFactory.NewVersion();
_nodeCache[newId] = modified;
return(newId);
}
