Golang pb.Data类代码示例

// 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
	}
}

// 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")
	default:
		return ft.ErrUnrecognizedType
	}
}

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

func (n *FSNode) GetBytes() ([]byte, error) {
	pbn := new(pb.Data)
	pbn.Type = &n.Type
	pbn.Filesize = proto.Uint64(uint64(len(n.Data)) + n.subtotal)
	pbn.Blocksizes = n.blocksizes
	pbn.Data = n.Data
	return proto.Marshal(pbn)
}

func (w *Writer) writeFile(nd *mdag.Node, pb *upb.Data, fpath string) error {
	if err := writeFileHeader(w.TarW, fpath, pb.GetFilesize()); err != nil {
		return err
	}

	dagr := uio.NewDataFileReader(w.ctx, nd, pb, w.Dag)
	_, err := dagr.WriteTo(w.TarW)
	return err
}

// Returns Bytes that represent a Directory
func FolderPBData() []byte {
	pbfile := new(pb.Data)
	typ := pb.Data_Directory
	pbfile.Type = &typ

	data, err := proto.Marshal(pbfile)
	if err != nil {
		//this really shouldnt happen, i promise
		panic(err)
	}
	return data
}

func BytesForMetadata(m *Metadata) ([]byte, error) {
	pbd := new(pb.Data)
	pbd.Filesize = proto.Uint64(m.Size)
	typ := pb.Data_Metadata
	pbd.Type = &typ
	mdd, err := m.Bytes()
	if err != nil {
		return nil, err
	}

	pbd.Data = mdd
	return proto.Marshal(pbd)
}

func SymlinkData(path string) ([]byte, error) {
	pbdata := new(pb.Data)
	typ := pb.Data_Symlink
	pbdata.Data = []byte(path)
	pbdata.Type = &typ

	out, err := proto.Marshal(pbdata)
	if err != nil {
		return nil, err
	}

	return out, nil
}

func NewPBFileReader(ctx context.Context, n *mdag.ProtoNode, pb *ftpb.Data, serv mdag.DAGService) *pbDagReader {
	fctx, cancel := context.WithCancel(ctx)
	promises := mdag.GetDAG(fctx, serv, n)
	return &pbDagReader{
		node:     n,
		serv:     serv,
		buf:      NewBufDagReader(pb.GetData()),
		promises: promises,
		ctx:      fctx,
		cancel:   cancel,
		pbdata:   pb,
	}
}

func NewDataFileReader(ctx context.Context, n *mdag.Node, pb *ftpb.Data, serv mdag.DAGService) *DagReader {
	fctx, cancel := context.WithCancel(ctx)
	promises := serv.GetDAG(fctx, n)
	return &DagReader{
		node:     n,
		serv:     serv,
		buf:      NewRSNCFromBytes(pb.GetData()),
		promises: promises,
		ctx:      fctx,
		cancel:   cancel,
		pbdata:   pb,
	}
}

func WrapData(b []byte) []byte {
	pbdata := new(pb.Data)
	typ := pb.Data_Raw
	pbdata.Data = b
	pbdata.Type = &typ

	out, err := proto.Marshal(pbdata)
	if err != nil {
		// This shouldnt happen. seriously.
		panic(err)
	}

	return out
}

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 (w *Writer) WriteNode(ctx cxt.Context, 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_Directory:
		return w.WriteDir(ctx, nd, fpath)
	case upb.Data_File:
		return w.writeFile(ctx, nd, pb, fpath)
	default:
		return fmt.Errorf("unixfs type not supported: %s", pb.GetType())
	}
}

func (w *Writer) writeFile(ctx cxt.Context, nd *mdag.Node, pb *upb.Data, fpath string) error {
	if err := writeFileHeader(w.TarW, fpath, pb.GetFilesize()); err != nil {
		return err
	}

	dagr, err := uio.NewDagReader(ctx, nd, w.Dag)
	if err != nil {
		return err
	}

	_, err = io.Copy(w.TarW, dagr)
	if err != nil && err != io.EOF {
		return err
	}

	return nil
}

func FilePBData(data []byte, totalsize uint64) []byte {
	pbfile := new(pb.Data)
	typ := pb.Data_File
	pbfile.Type = &typ
	pbfile.Data = data
	pbfile.Filesize = proto.Uint64(totalsize)

	data, err := proto.Marshal(pbfile)
	if err != nil {
		// This really shouldnt happen, i promise
		// The only failure case for marshal is if required fields
		// are not filled out, and they all are. If the proto object
		// gets changed and nobody updates this function, the code
		// should panic due to programmer error
		panic(err)
	}
	return data
}