private void MakeStack(ShaMapInner root, Hash256 index)
{
_inners = new LinkedList <ShaMapInner>();
var top = root;
while (true)
{
_inners.AddLast(top);
var existing = top.GetBranch(index);
if (existing == null)
{
break;
}
if (existing.IsLeaf)
{
Leaf = existing.AsLeaf();
_matched = Leaf.Index.Equals(index);
break;
}
if (existing.IsInner)
{
top = existing.AsInner();
}
}
}
// Descend into the tree, find the leaf matching this index
// and if the tree has it.
protected internal void SetLeaf(ShaMapLeaf leaf)
{
if (leaf.Version == -1)
{
leaf.Version = Version;
}
SetBranch(leaf.Index, leaf);
}
public bool AddLeaf(ShaMapLeaf leaf)
{
var stack = PathToIndex(leaf.Index);
if (stack.HasMatchedLeaf())
{
return(false);
}
var top = stack.DirtyOrCopyInners();
top.AddLeafToTerminalInner(leaf);
return(true);
}
public bool UpdateLeaf(ShaMapLeaf leaf)
{
var stack = PathToIndex(leaf.Index);
if (!stack.HasMatchedLeaf())
{
return(false);
}
var top = stack.DirtyOrCopyInners();
// Why not update in place? Because of structural sharing
top.SetLeaf(leaf);
return(true);
}
public void CollapseOnlyLeafChildInners()
{
Debug.Assert(_dirtied != null);
ShaMapLeaf onlyChild = null;
for (var i = _dirtied.Length - 1; i >= 0; i--)
{
var next = _dirtied[i];
if (onlyChild != null)
{
next.SetLeaf(onlyChild);
}
onlyChild = next.OnlyChildLeaf();
if (onlyChild == null)
{
break;
}
}
}
/// <summary>
/// This should only be called on the deepest inners, as it
/// does not do any dirtying. </summary>
/// <param name="leaf"> to add to inner </param>
internal void AddLeafToTerminalInner(ShaMapLeaf leaf)
{
var branch = GetBranch(leaf.Index);
if (branch == null)
{
SetLeaf(leaf);
}
else if (branch.IsInner)
{
throw new InvalidOperationException();
}
else if (branch.IsLeaf)
{
var inner = MakeInnerChild();
SetBranch(leaf.Index, inner);
inner.AddLeafToTerminalInner(leaf);
inner.AddLeafToTerminalInner(branch.AsLeaf());
}
}
/// <returns> the `only child` leaf or null if other children </returns>
public ShaMapLeaf OnlyChildLeaf()
{
ShaMapLeaf leaf = null;
var leaves = 0;
foreach (var branch in Branches.Where(branch => branch != null))
{
if (branch.IsInner)
{
leaf = null;
break;
}
if (++leaves == 1)
{
leaf = branch.AsLeaf();
}
else
{
leaf = null;
break;
}
}
return(leaf);
}
