示例#1
0
// converts the Node object into a real dag.Node
func deserializeNode(node *Node) (*dag.Node, error) {
	dagnode := new(dag.Node)
	dagnode.Data = []byte(node.Data)
	dagnode.Links = make([]*dag.Link, len(node.Links))
	for i, link := range node.Links {
		hash, err := mh.FromB58String(link.Hash)
		if err != nil {
			return nil, err
		}
		dagnode.Links[i] = &dag.Link{
			Name: link.Name,
			Size: link.Size,
			Hash: hash,
		}
	}

	return dagnode, nil
}
示例#2
0
// dagTruncate truncates the given node to 'size' and returns the modified Node
func dagTruncate(ctx context.Context, nd *mdag.Node, size uint64, ds mdag.DAGService) (*mdag.Node, 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.Data = ft.WrapData(pbn.Data[:size])
		return nd, nil
	}

	var cur uint64
	end := 0
	var modified *mdag.Node
	ndata := new(ft.FSNode)
	for i, lnk := range nd.Links {
		child, err := lnk.GetNode(ctx, ds)
		if err != nil {
			return nil, err
		}

		childsize, err := ft.DataSize(child.Data)
		if err != nil {
			return nil, err
		}

		// found the child we want to cut
		if size < cur+childsize {
			nchild, err := dagTruncate(ctx, child, 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.Links = nd.Links[:end]
	err = nd.AddNodeLinkClean("", modified)
	if err != nil {
		return nil, err
	}

	d, err := ndata.GetBytes()
	if err != nil {
		return nil, err
	}

	nd.Data = d

	// invalidate cache and recompute serialized data
	_, err = nd.Encoded(true)
	if err != nil {
		return nil, err
	}

	return nd, nil
}