Golang Node.SetData方法代码示例

// 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.SetData([]byte(node.Data))
	case "base64":
		data, _ := base64.StdEncoding.DecodeString(node.Data)
		dagnode.SetData(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 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 (d *Directory) Mkdir(name string) (*Directory, error) {
	d.lock.Lock()
	defer d.lock.Unlock()

	fsn, err := d.childUnsync(name)
	if err == nil {
		switch fsn := fsn.(type) {
		case *Directory:
			return fsn, os.ErrExist
		case *File:
			return nil, os.ErrExist
		default:
			return nil, fmt.Errorf("unrecognized type: %#v", fsn)
		}
	}

	ndir := new(dag.Node)
	ndir.SetData(ft.FolderPBData())

	_, err = d.dserv.Add(ndir)
	if err != nil {
		return nil, err
	}

	err = d.node.AddNodeLinkClean(name, ndir)
	if err != nil {
		return nil, err
	}

	dirobj := NewDirectory(d.ctx, name, ndir, d, d.dserv)
	d.childDirs[name] = dirobj
	return dirobj, nil
}

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.SetData([]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.SetData(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)
}

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 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.SetData(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 (s *Shell) NewObject(template string) (string, error) {
	node := new(dag.Node)
	switch template {
	case "":
		break
	case "unixfs-dir":
		node.SetData(ft.FolderPBData())
	default:
		return "", fmt.Errorf("unknown template %s", template)
	}
	c, err := s.node.DAG.Add(node)
	if err != nil {
		return "", err
	}

	return c.String(), nil
}

func TestAppendSingleBytesToEmpty(t *testing.T) {
	ds := mdtest.Mock()

	data := []byte("AB")

	nd := new(merkledag.Node)
	nd.SetData(ft.FilePBData(nil, 0))

	dbp := &h.DagBuilderParams{
		Dagserv:  ds,
		Maxlinks: 4,
	}

	spl := chunk.SizeSplitterGen(500)

	ctx := context.Background()
	nnode, err := TrickleAppend(ctx, nd, dbp.New(spl(bytes.NewReader(data[:1]))))
	if err != nil {
		t.Fatal(err)
	}

	nnode, err = TrickleAppend(ctx, nnode, dbp.New(spl(bytes.NewReader(data[1:]))))
	if err != nil {
		t.Fatal(err)
	}

	fread, err := uio.NewDagReader(ctx, nnode, ds)
	if err != nil {
		t.Fatal(err)
	}

	out, err := ioutil.ReadAll(fread)
	if err != nil {
		t.Fatal(err)
	}

	fmt.Println(out, data)
	err = arrComp(out, data)
	if err != nil {
		t.Fatal(err)
	}
}

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

// 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.SetData(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.SetData(d)

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

	return nd, nil
}

// modifyDag writes the data in 'data' over the data in 'node' starting at 'offset'
// returns the new key of the passed in node and whether or not all the data in the reader
// has been consumed.
func (dm *DagModifier) modifyDag(node *mdag.Node, offset uint64, data io.Reader) (key.Key, bool, error) {
	f, err := ft.FromBytes(node.Data())
	if err != nil {
		return "", false, err
	}

	// If we've reached a leaf node.
	if len(node.Links) == 0 {
		n, err := data.Read(f.Data[offset:])
		if err != nil && err != io.EOF {
			return "", false, err
		}

		// Update newly written node..
		b, err := proto.Marshal(f)
		if err != nil {
			return "", false, err
		}

		nd := new(mdag.Node)
		nd.SetData(b)
		k, err := dm.dagserv.Add(nd)
		if err != nil {
			return "", false, err
		}

		// Hey look! we're done!
		var done bool
		if n < len(f.Data[offset:]) {
			done = true
		}

		return k, done, nil
	}

	var cur uint64
	var done bool
	for i, bs := range f.GetBlocksizes() {
		// We found the correct child to write into
		if cur+bs > offset {
			child, err := node.Links[i].GetNode(dm.ctx, dm.dagserv)
			if err != nil {
				return "", false, err
			}
			k, sdone, err := dm.modifyDag(child, offset-cur, data)
			if err != nil {
				return "", false, err
			}

			offset += bs
			node.Links[i].Hash = mh.Multihash(k)

			// Recache serialized node
			_, err = node.EncodeProtobuf(true)
			if err != nil {
				return "", false, err
			}

			if sdone {
				// No more bytes to write!
				done = true
				break
			}
			offset = cur + bs
		}
		cur += bs
	}

	k, err := dm.dagserv.Add(node)
	return k, done, err
}

// NewEmptyDirectory returns an empty merkledag Node with a folder Data chunk
func NewEmptyDirectory() *mdag.Node {
	nd := new(mdag.Node)
	nd.SetData(format.FolderPBData())
	return nd
}