improves memory usage of add

License: MIT
Signed-off-by: Jeromy <jeromyj@gmail.com>

merkledag.go

@@ -20,6 +20,7 @@ type DAGService interface {
 	AddRecursive(*Node) error
 	Get(context.Context, key.Key) (*Node, error)
 	Remove(*Node) error
+	RemoveRecursive(*Node) error
 
 	// GetDAG returns, in order, all the single leve child
 	// nodes of the passed in node.
@@ -107,12 +108,20 @@ func (n *dagService) Get(ctx context.Context, k key.Key) (*Node, error) {
 }
 
 // Remove deletes the given node and all of its children from the BlockService
-func (n *dagService) Remove(nd *Node) error {
+func (n *dagService) RemoveRecursive(nd *Node) error {
 	for _, l := range nd.Links {
 		if l.Node != nil {
-			n.Remove(l.Node)
+			n.RemoveRecursive(l.Node)
+		}
 	}
+	k, err := nd.Key()
+	if err != nil {
+		return err
 	}
+	return n.Blocks.DeleteBlock(k)
+}
+
+func (n *dagService) Remove(nd *Node) error {
 	k, err := nd.Key()
 	if err != nil {
 		return err

utils/utils.go

@@ -40,6 +40,8 @@ func addLink(ctx context.Context, ds dag.DAGService, root *dag.Node, childname s
 		return nil, err
 	}
 
+	_ = ds.Remove(root)
+
 	// ensure no link with that name already exists
 	_ = root.RemoveNodeLink(childname) // ignore error, only option is ErrNotFound
 
@@ -83,6 +85,8 @@ func insertNodeAtPath(ctx context.Context, ds dag.DAGService, root *dag.Node, pa
 		return nil, err
 	}
 
+	_ = ds.Remove(root)
+
 	_ = root.RemoveNodeLink(path[0])
 	err = root.AddNodeLinkClean(path[0], ndprime)
 	if err != nil {
@@ -133,6 +137,8 @@ func rmLink(ctx context.Context, ds dag.DAGService, root *dag.Node, path []strin
 		return nil, err
 	}
 
+	_ = ds.Remove(root)
+
 	_ = root.RemoveNodeLink(path[0])
 	err = root.AddNodeLinkClean(path[0], nnode)
 	if err != nil {