// converts the Node object into a real dag.ProtoNode func deserializeNode(nd *Node, dataFieldEncoding string) (*dag.ProtoNode, error) { dagnode := new(dag.ProtoNode) switch dataFieldEncoding { case "text": dagnode.SetData([]byte(nd.Data)) case "base64": data, _ := base64.StdEncoding.DecodeString(nd.Data) dagnode.SetData(data) default: return nil, fmt.Errorf("Unkown data field encoding") } dagnode.SetLinks(make([]*node.Link, len(nd.Links))) for i, link := range nd.Links { c, err := cid.Decode(link.Hash) if err != nil { return nil, err } dagnode.Links()[i] = &node.Link{ Name: link.Name, Size: link.Size, Cid: c, } } return dagnode, nil }
// dagTruncate truncates the given node to 'size' and returns the modified Node func dagTruncate(ctx context.Context, nd *mdag.ProtoNode, size uint64, ds mdag.DAGService) (*mdag.ProtoNode, error) { if len(nd.Links()) == 0 { // TODO: this can likely be done without marshaling and remarshaling pbn, err := ft.FromBytes(nd.Data()) if err != nil { return nil, err } nd.SetData(ft.WrapData(pbn.Data[:size])) return nd, nil } var cur uint64 end := 0 var modified *mdag.ProtoNode ndata := new(ft.FSNode) for i, lnk := range nd.Links() { child, err := lnk.GetNode(ctx, ds) if err != nil { return nil, err } childpb, ok := child.(*mdag.ProtoNode) if !ok { return nil, err } childsize, err := ft.DataSize(childpb.Data()) if err != nil { return nil, err } // found the child we want to cut if size < cur+childsize { nchild, err := dagTruncate(ctx, childpb, size-cur, ds) if err != nil { return nil, err } ndata.AddBlockSize(size - cur) modified = nchild end = i break } cur += childsize ndata.AddBlockSize(childsize) } _, err := ds.Add(modified) if err != nil { return nil, err } nd.SetLinks(nd.Links()[:end]) err = nd.AddNodeLinkClean("", modified) if err != nil { return nil, err } d, err := ndata.GetBytes() if err != nil { return nil, err } nd.SetData(d) // invalidate cache and recompute serialized data _, err = nd.EncodeProtobuf(true) if err != nil { return nil, err } return nd, nil }