Golang Node.Data方法代码示例

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

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

	data := []byte("AB")

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

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

	spl := chunk.SizeSplitterGen(500)

	blks, errs := chunk.Chan(spl(bytes.NewReader(data[:1])))

	ctx := context.Background()
	nnode, err := TrickleAppend(ctx, nd, dbp.New(blks, errs))
	if err != nil {
		t.Fatal(err)
	}

	blks, errs = chunk.Chan(spl(bytes.NewReader(data[1:])))

	nnode, err = TrickleAppend(ctx, nnode, dbp.New(blks, errs))
	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)
	}
}

// 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
}

func setDataCaller(req cmds.Request, root *dag.Node) (key.Key, error) {
	if len(req.Arguments()) < 3 {
		return "", fmt.Errorf("not enough arguments for set-data")
	}

	nd, err := req.InvocContext().GetNode()
	if err != nil {
		return "", err
	}

	root.Data = []byte(req.Arguments()[2])

	newkey, err := nd.DAG.Add(root)
	if err != nil {
		return "", err
	}

	return newkey, 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.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
}

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(ds, root)

	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, nil)
			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
		}
	}

	root = e.GetNode()
	_, err = ds.Add(root)
	if err != nil {
		return nil, err
	}

	return root, nil
}