Golang Data.GetType方法代码示例

// 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 FSNodeFromBytes(b []byte) (*FSNode, error) {
	pbn := new(pb.Data)
	err := proto.Unmarshal(b, pbn)
	if err != nil {
		return nil, err
	}

	n := new(FSNode)
	n.Data = pbn.Data
	n.blocksizes = pbn.Blocksizes
	n.subtotal = pbn.GetFilesize() - uint64(len(n.Data))
	n.Type = pbn.GetType()
	return n, nil
}

func DataSize(data []byte) (uint64, error) {
	pbdata := new(pb.Data)
	err := proto.Unmarshal(data, pbdata)
	if err != nil {
		return 0, err
	}

	switch pbdata.GetType() {
	case pb.Data_Directory:
		return 0, errors.New("Cant get data size of directory!")
	case pb.Data_File:
		return pbdata.GetFilesize(), nil
	case pb.Data_Raw:
		return uint64(len(pbdata.GetData())), nil
	default:
		return 0, errors.New("Unrecognized node data type!")
	}
}

func MetadataFromBytes(b []byte) (*Metadata, error) {
	pbd := new(pb.Data)
	err := proto.Unmarshal(b, pbd)
	if err != nil {
		return nil, err
	}
	if pbd.GetType() != pb.Data_Metadata {
		return nil, errors.New("incorrect node type")
	}

	pbm := new(pb.Metadata)
	err = proto.Unmarshal(pbd.Data, pbm)
	if err != nil {
		return nil, err
	}
	md := new(Metadata)
	md.MimeType = pbm.GetMimeType()
	return md, nil
}

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
	}
}

// precalcNextBuf follows the next link in line and loads it from the DAGService,
// setting the next buffer to read from
func (dr *DagReader) precalcNextBuf(ctx context.Context) error {
	dr.buf.Close() // Just to make sure
	if dr.linkPosition >= len(dr.promises) {
		return io.EOF
	}

	nxt, err := dr.promises[dr.linkPosition].Get(ctx)
	if err != nil {
		return err
	}
	dr.linkPosition++

	pb := new(ftpb.Data)
	err = proto.Unmarshal(nxt.Data, pb)
	if err != nil {
		return fmt.Errorf("incorrectly formatted protobuf: %s", err)
	}

	switch pb.GetType() {
	case ftpb.Data_Directory:
		// A directory should not exist within a file
		return ft.ErrInvalidDirLocation
	case ftpb.Data_File:
		dr.buf = NewDataFileReader(dr.ctx, nxt, pb, dr.serv)
		return nil
	case ftpb.Data_Raw:
		dr.buf = NewRSNCFromBytes(pb.GetData())
		return nil
	case ftpb.Data_Metadata:
		return errors.New("Shouldnt have had metadata object inside file")
	case ftpb.Data_Symlink:
		return errors.New("shouldnt have had symlink inside file")
	default:
		return ft.ErrUnrecognizedType
	}
}