// 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
}
// 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
}
}