func TrickleLayout(db *h.DagBuilderHelper) (*dag.Node, error) {
root := h.NewUnixfsNode()
if err := db.FillNodeLayer(root); err != nil {
return nil, err
}
for level := 1; !db.Done(); level++ {
for i := 0; i < layerRepeat && !db.Done(); i++ {
next := h.NewUnixfsNode()
if err := fillTrickleRec(db, next, level); err != nil {
return nil, err
}
if err := root.AddChild(next, db); err != nil {
return nil, err
}
}
}
out, err := db.Add(root)
if err != nil {
return nil, err
}
if err := db.Close(); err != nil {
return nil, err
}
return out, nil
}
// 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) 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.
return db.FillNodeWithData(node)
}
// while we have room AND we're not done
for node.NumChildren() < db.Maxlinks() && !db.Done() {
child := h.NewUnixfsNode()
if err := fillNodeRec(db, child, depth-1); err != nil {
return err
}
if err := node.AddChild(child, db); err != nil {
return err
}
}
return nil
}
// TrickleAppend appends the data in `db` to the dag, using the Trickledag format
func TrickleAppend(ctx context.Context, base *dag.Node, db *h.DagBuilderHelper) (out *dag.Node, err_out error) {
defer func() {
if err_out == nil {
if err := db.Close(); err != nil {
err_out = err
}
}
}()
// Convert to unixfs node for working with easily
ufsn, err := h.NewUnixfsNodeFromDag(base)
if err != nil {
return nil, err
}
// Get depth of this 'tree'
n, layerProgress := trickleDepthInfo(ufsn, db.Maxlinks())
if n == 0 {
// If direct blocks not filled...
if err := db.FillNodeLayer(ufsn); err != nil {
return nil, err
}
if db.Done() {
return ufsn.GetDagNode()
}
// If continuing, our depth has increased by one
n++
}
// Last child in this node may not be a full tree, lets file it up
if err := appendFillLastChild(ctx, ufsn, n-1, layerProgress, db); err != nil {
return nil, err
}
// after appendFillLastChild, our depth is now increased by one
if !db.Done() {
n++
}
// Now, continue filling out tree like normal
for i := n; !db.Done(); i++ {
for j := 0; j < layerRepeat && !db.Done(); j++ {
next := h.NewUnixfsNode()
err := fillTrickleRec(db, next, i)
if err != nil {
return nil, err
}
err = ufsn.AddChild(next, db)
if err != nil {
return nil, err
}
}
}
return ufsn.GetDagNode()
}
func BalancedLayout(db *h.DagBuilderHelper) (*dag.Node, error) {
var root *h.UnixfsNode
for level := 0; !db.Done(); level++ {
nroot := h.NewUnixfsNode()
// 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); err != nil {
return nil, err
}
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
}
// recursive call for TrickleAppend
func trickleAppendRec(ctx context.Context, ufsn *h.UnixfsNode, db *h.DagBuilderHelper, depth int) (*h.UnixfsNode, error) {
if depth == 0 || db.Done() {
return ufsn, nil
}
// Get depth of this 'tree'
n, layerProgress := trickleDepthInfo(ufsn, db.Maxlinks())
if n == 0 {
// If direct blocks not filled...
if err := db.FillNodeLayer(ufsn); err != nil {
return nil, err
}
n++
}
// If at correct depth, no need to continue
if n == depth {
return ufsn, nil
}
if err := appendFillLastChild(ctx, ufsn, n, layerProgress, db); err != nil {
return nil, err
}
// after appendFillLastChild, our depth is now increased by one
if !db.Done() {
n++
}
// Now, continue filling out tree like normal
for i := n; i < depth && !db.Done(); i++ {
for j := 0; j < layerRepeat && !db.Done(); j++ {
next := h.NewUnixfsNode()
if err := fillTrickleRec(db, next, i); err != nil {
return nil, err
}
if err := ufsn.AddChild(next, db); err != nil {
return nil, err
}
}
}
return ufsn, nil
}
// appendFillLastChild will take in an incomplete trickledag node (uncomplete meaning, not full) and
// fill it out to the specified depth with blocks from the given DagBuilderHelper
func appendFillLastChild(ctx context.Context, ufsn *h.UnixfsNode, depth int, layerFill int, db *h.DagBuilderHelper) error {
if ufsn.NumChildren() <= db.Maxlinks() {
return nil
}
// Recursive step, grab last child
last := ufsn.NumChildren() - 1
lastChild, err := ufsn.GetChild(ctx, last, db.GetDagServ())
if err != nil {
return err
}
// Fill out last child (may not be full tree)
nchild, err := trickleAppendRec(ctx, lastChild, db, depth-1)
if err != nil {
return err
}
// Update changed child in parent node
ufsn.RemoveChild(last, db)
err = ufsn.AddChild(nchild, db)
if err != nil {
return err
}
// Partially filled depth layer
if layerFill != 0 {
for ; layerFill < layerRepeat && !db.Done(); layerFill++ {
next := h.NewUnixfsNode()
err := fillTrickleRec(db, next, depth)
if err != nil {
return err
}
err = ufsn.AddChild(next, db)
if err != nil {
return err
}
}
}
return nil
}
func fillTrickleRec(db *h.DagBuilderHelper, node *h.UnixfsNode, depth int) error {
// Always do this, even in the base case
if err := db.FillNodeLayer(node); err != nil {
return err
}
for i := 1; i < depth && !db.Done(); i++ {
for j := 0; j < layerRepeat && !db.Done(); j++ {
next := h.NewUnixfsNode()
if err := fillTrickleRec(db, next, i); err != nil {
return err
}
if err := node.AddChild(next, db); err != nil {
return err
}
}
}
return nil
}