Golang Node.Data方法代码示例

func readHdr(n *merkledag.Node) (*pb.Set, []byte, error) {
	hdrLenRaw, consumed := binary.Uvarint(n.Data())
	if consumed <= 0 {
		return nil, nil, errors.New("invalid Set header length")
	}
	buf := n.Data()[consumed:]
	if hdrLenRaw > uint64(len(buf)) {
		return nil, nil, errors.New("impossibly large Set header length")
	}
	// as hdrLenRaw was <= an int, we now know it fits in an int
	hdrLen := int(hdrLenRaw)
	var hdr pb.Set
	if err := proto.Unmarshal(buf[:hdrLen], &hdr); err != nil {
		return nil, nil, err
	}
	buf = buf[hdrLen:]

	if v := hdr.GetVersion(); v != 1 {
		return nil, nil, fmt.Errorf("unsupported Set version: %d", v)
	}
	if uint64(hdr.GetFanout()) > uint64(len(n.Links)) {
		return nil, nil, errors.New("impossibly large Fanout")
	}
	return &hdr, buf, nil
}

// NewDagReader creates a new reader object that reads the data represented by
// the given node, using the passed in DAGService for data retreival
func NewDagReader(ctx context.Context, n *mdag.Node, serv mdag.DAGService) (*DagReader, error) {
	pb := new(ftpb.Data)
	if err := proto.Unmarshal(n.Data(), pb); err != nil {
		return nil, err
	}

	switch pb.GetType() {
	case ftpb.Data_Directory:
		// Dont allow reading directories
		return nil, ErrIsDir
	case ftpb.Data_Raw:
		fallthrough
	case ftpb.Data_File:
		return NewDataFileReader(ctx, n, pb, serv), nil
	case ftpb.Data_Metadata:
		if len(n.Links) == 0 {
			return nil, errors.New("incorrectly formatted metadata object")
		}
		child, err := n.Links[0].GetNode(ctx, serv)
		if err != nil {
			return nil, err
		}
		return NewDagReader(ctx, child, serv)
	case ftpb.Data_Symlink:
		return nil, ErrCantReadSymlinks
	default:
		return nil, ft.ErrUnrecognizedType
	}
}

func printDag(nd *mdag.Node, ds mdag.DAGService, indent int) {
	pbd, err := ft.FromBytes(nd.Data())
	if err != nil {
		panic(err)
	}

	for i := 0; i < indent; i++ {
		fmt.Print(" ")
	}
	fmt.Printf("{size = %d, type = %s, children = %d", pbd.GetFilesize(), pbd.GetType().String(), len(pbd.GetBlocksizes()))
	if len(nd.Links) > 0 {
		fmt.Println()
	}
	for _, lnk := range nd.Links {
		child, err := lnk.GetNode(context.Background(), ds)
		if err != nil {
			panic(err)
		}
		printDag(child, ds, indent+1)
	}
	if len(nd.Links) > 0 {
		for i := 0; i < indent; i++ {
			fmt.Print(" ")
		}
	}
	fmt.Println("}")
}

func randNode() (*mdag.Node, key.Key) {
	nd := new(mdag.Node)
	nd.SetData(make([]byte, 32))
	util.NewTimeSeededRand().Read(nd.Data())
	k, _ := nd.Key()
	return nd, k
}

func randNode() (*merkledag.Node, key.Key) {
	node := new(merkledag.Node)
	node.SetData(make([]byte, 32))
	util.NewTimeSeededRand().Read(node.Data())
	k, _ := node.Key()
	return node, k
}

func ImportTar(r io.Reader, ds dag.DAGService) (*dag.Node, error) {
	rall, err := ioutil.ReadAll(r)
	if err != nil {
		return nil, err
	}

	r = bytes.NewReader(rall)

	tr := tar.NewReader(r)

	root := new(dag.Node)
	root.Data = []byte("ipfs/tar")

	e := dagutil.NewDagEditor(root, ds)

	for {
		h, err := tr.Next()
		if err != nil {
			if err == io.EOF {
				break
			}
			return nil, err
		}

		header := new(dag.Node)

		headerBytes, err := marshalHeader(h)
		if err != nil {
			return nil, err
		}

		header.Data = headerBytes

		if h.Size > 0 {
			spl := chunk.NewRabin(tr, uint64(chunk.DefaultBlockSize))
			nd, err := importer.BuildDagFromReader(ds, spl)
			if err != nil {
				return nil, err
			}

			err = header.AddNodeLinkClean("data", nd)
			if err != nil {
				return nil, err
			}
		}

		_, err = ds.Add(header)
		if err != nil {
			return nil, err
		}

		path := escapePath(h.Name)
		err = e.InsertNodeAtPath(context.Background(), path, header, func() *dag.Node { return new(dag.Node) })
		if err != nil {
			return nil, err
		}
	}

	return e.Finalize(ds)
}

// Recursive call for verifying the structure of a trickledag
func verifyTDagRec(nd *dag.Node, depth, direct, layerRepeat int, ds dag.DAGService) error {
	if depth == 0 {
		// zero depth dag is raw data block
		if len(nd.Links) > 0 {
			return errors.New("expected direct block")
		}

		pbn, err := ft.FromBytes(nd.Data())
		if err != nil {
			return err
		}

		if pbn.GetType() != ft.TRaw {
			return errors.New("Expected raw block")
		}
		return nil
	}

	// Verify this is a branch node
	pbn, err := ft.FromBytes(nd.Data())
	if err != nil {
		return err
	}

	if pbn.GetType() != ft.TFile {
		return errors.New("expected file as branch node")
	}

	if len(pbn.Data) > 0 {
		return errors.New("branch node should not have data")
	}

	for i := 0; i < len(nd.Links); i++ {
		child, err := nd.Links[i].GetNode(context.TODO(), ds)
		if err != nil {
			return err
		}

		if i < direct {
			// Direct blocks
			err := verifyTDagRec(child, 0, direct, layerRepeat, ds)
			if err != nil {
				return err
			}
		} else {
			// Recursive trickle dags
			rdepth := ((i - direct) / layerRepeat) + 1
			if rdepth >= depth && depth > 0 {
				return errors.New("Child dag was too deep!")
			}
			err := verifyTDagRec(child, rdepth, direct, layerRepeat, ds)
			if err != nil {
				return err
			}
		}
	}
	return nil
}

func addLink(t *testing.T, ds mdag.DAGService, a, b *mdag.Node) {
	to := string(a.Data()) + "2" + string(b.Data())
	if _, err := ds.Add(b); err != nil {
		t.Error(err)
	}
	if err := a.AddNodeLink(to, b); err != nil {
		t.Error(err)
	}
}

func ExportTar(ctx context.Context, root *dag.Node, ds dag.DAGService) (io.Reader, error) {
	if string(root.Data()) != "ipfs/tar" {
		return nil, errors.New("not an ipfs tarchive")
	}
	return &tarReader{
		links: root.Links,
		ds:    ds,
		ctx:   ctx,
	}, nil
}

// NewUnixfsNodeFromDag reconstructs a Unixfs node from a given dag node
func NewUnixfsNodeFromDag(nd *dag.Node) (*UnixfsNode, error) {
	mb, err := ft.FSNodeFromBytes(nd.Data())
	if err != nil {
		return nil, err
	}

	return &UnixfsNode{
		node: nd,
		ufmt: mb,
	}, nil
}

func writeHdr(n *merkledag.Node, hdr *pb.Set) error {
	hdrData, err := proto.Marshal(hdr)
	if err != nil {
		return err
	}
	n.Data = make([]byte, binary.MaxVarintLen64, binary.MaxVarintLen64+len(hdrData))
	written := binary.PutUvarint(n.Data, uint64(len(hdrData)))
	n.Data = n.Data[:written]
	n.Data = append(n.Data, hdrData...)
	return nil
}

// converts the Node object into a real dag.Node
func deserializeNode(node *Node, dataFieldEncoding string) (*dag.Node, error) {
	dagnode := new(dag.Node)
	switch dataFieldEncoding {
	case "text":
		dagnode.Data = []byte(node.Data)
	case "base64":
		dagnode.Data, _ = base64.StdEncoding.DecodeString(node.Data)
	default:
		return nil, fmt.Errorf("Unkown data field encoding")
	}

	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
}

func AddMetadataTo(n *core.IpfsNode, skey string, m *ft.Metadata) (string, error) {
	ukey := key.B58KeyDecode(skey)

	nd, err := n.DAG.Get(n.Context(), ukey)
	if err != nil {
		return "", err
	}

	mdnode := new(dag.Node)
	mdata, err := ft.BytesForMetadata(m)
	if err != nil {
		return "", err
	}

	mdnode.Data = mdata
	if err := mdnode.AddNodeLinkClean("file", nd); err != nil {
		return "", err
	}

	nk, err := n.DAG.Add(mdnode)
	if err != nil {
		return "", err
	}

	return nk.B58String(), nil
}

func nodeFromTemplate(template string) (*dag.Node, error) {
	switch template {
	case "unixfs-dir":
		nd := new(dag.Node)
		nd.Data = ft.FolderPBData()
		return nd, nil
	default:
		return nil, fmt.Errorf("template '%s' not found", template)
	}
}

func (w *Writer) WriteNode(nd *mdag.Node, fpath string) error {
	pb := new(upb.Data)
	if err := proto.Unmarshal(nd.Data(), pb); err != nil {
		return err
	}

	switch pb.GetType() {
	case upb.Data_Metadata:
		fallthrough
	case upb.Data_Directory:
		return w.writeDir(nd, fpath)
	case upb.Data_Raw:
		fallthrough
	case upb.Data_File:
		return w.writeFile(nd, pb, fpath)
	case upb.Data_Symlink:
		return writeSymlinkHeader(w.TarW, string(pb.GetData()), fpath)
	default:
		return ft.ErrUnrecognizedType
	}
}