func insertNodeAtPath(ctx context.Context, ds dag.DAGService, root *dag.Node, path []string, toinsert *dag.Node, create func() *dag.Node) (*dag.Node, error) {
if len(path) == 1 {
return addLink(ctx, ds, root, path[0], toinsert)
}
nd, err := root.GetLinkedNode(ctx, ds, path[0])
if err != nil {
// if 'create' is true, we create directories on the way down as needed
if err == dag.ErrNotFound && create != nil {
nd = create()
} else {
return nil, err
}
}
ndprime, err := insertNodeAtPath(ctx, ds, nd, path[1:], toinsert, create)
if err != nil {
return nil, err
}
_ = root.RemoveNodeLink(path[0])
err = root.AddNodeLinkClean(path[0], ndprime)
if err != nil {
return nil, err
}
_, err = ds.Add(root)
if err != nil {
return nil, err
}
return root, nil
}
func rmLink(ctx context.Context, ds dag.DAGService, root *dag.Node, path []string) (*dag.Node, error) {
if len(path) == 1 {
// base case, remove node in question
err := root.RemoveNodeLink(path[0])
if err != nil {
return nil, err
}
_, err = ds.Add(root)
if err != nil {
return nil, err
}
return root, nil
}
nd, err := root.GetLinkedNode(ctx, ds, path[0])
if err != nil {
return nil, err
}
nnode, err := rmLink(ctx, ds, nd, path[1:])
if err != nil {
return nil, err
}
_ = root.RemoveNodeLink(path[0])
err = root.AddNodeLinkClean(path[0], nnode)
if err != nil {
return nil, err
}
_, err = ds.Add(root)
if err != nil {
return nil, err
}
return root, nil
}
func addLink(ctx context.Context, ds dag.DAGService, root *dag.Node, childname string, childnd *dag.Node) (*dag.Node, error) {
if childname == "" {
return nil, errors.New("cannot create link with no name!")
}
// ensure that the node we are adding is in the dagservice
_, err := ds.Add(childnd)
if err != nil {
return nil, err
}
// ensure no link with that name already exists
_ = root.RemoveNodeLink(childname) // ignore error, only option is ErrNotFound
if err := root.AddNodeLinkClean(childname, childnd); err != nil {
return nil, err
}
if _, err := ds.Add(root); err != nil {
return nil, err
}
return root, nil
}