// fillNodeRec will fill the given node with data from the dagBuilders input
// source down to an indirection depth as specified by 'depth'
// it returns the total dataSize of the node, and a potential error
//
// warning: **children** pinned indirectly, but input node IS NOT pinned.
func fillNodeRec(db *h.DagBuilderHelper, node *h.UnixfsNode, depth int, offset uint64) error {
if depth < 0 {
return errors.New("attempt to fillNode at depth < 0")
}
// Base case
if depth <= 0 { // catch accidental -1's in case error above is removed.
child, err := db.GetNextDataNode()
if err != nil {
return err
}
node.Set(child)
return nil
}
// while we have room AND we're not done
for node.NumChildren() < db.Maxlinks() && !db.Done() {
child := h.NewUnixfsNode()
db.SetPosInfo(child, offset)
err := fillNodeRec(db, child, depth-1, offset)
if err != nil {
return err
}
if err := node.AddChild(child, db); err != nil {
return err
}
offset += child.FileSize()
}
return nil
}
func BalancedLayout(db *h.DagBuilderHelper) (node.Node, error) {
var offset uint64 = 0
var root *h.UnixfsNode
for level := 0; !db.Done(); level++ {
nroot := h.NewUnixfsNode()
db.SetPosInfo(nroot, 0)
// add our old root as a child of the new root.
if root != nil { // nil if it's the first node.
if err := nroot.AddChild(root, db); err != nil {
return nil, err
}
}
// fill it up.
if err := fillNodeRec(db, nroot, level, offset); err != nil {
return nil, err
}
offset = nroot.FileSize()
root = nroot
}
if root == nil {
root = h.NewUnixfsNode()
}
out, err := db.Add(root)
if err != nil {
return nil, err
}
err = db.Close()
if err != nil {
return nil, err
}
return out, nil
}
