Create bufDagReader

License: MIT
Signed-off-by: Jakub Sztandera <kubuxu@protonmail.ch>

unixfs/io/bufdagreader.go

+package io
+
+import (
+	"bytes"
+	"context"
+	"io"
+)
+
+type bufDagReader struct {
+	*bytes.Reader
+}
+
+func NewBufDagReader(b []byte) *bufDagReader {
+	return &bufDagReader{bytes.NewReader(b)}
+}
+
+var _ DagReader = (*bufDagReader)(nil)
+
+func (*bufDagReader) Close() error {
+	return nil
+}
+
+func (rd *bufDagReader) CtxReadFull(ctx context.Context, b []byte) (int, error) {
+	return rd.Read(b)
+}
+
+func (rd *bufDagReader) Offset() int64 {
+	of, err := rd.Seek(0, io.SeekCurrent)
+	if err != nil {
+		panic("this should never happen " + err.Error())
+	}
+	return of
+}
+
+func (rd *bufDagReader) Size() uint64 {
+	s := rd.Reader.Size()
+	if s < 0 {
+		panic("size smaller than 0 (impossible!!)")
+	}
+	return uint64(s)
+}

unixfs/io/dagreader.go

@@ -37,9 +37,7 @@ type ReadSeekCloser interface {
 func NewDagReader(ctx context.Context, n node.Node, serv mdag.DAGService) (DagReader, error) {
 	switch n := n.(type) {
 	case *mdag.RawNode:
-		return &pbDagReader{
-			buf: NewRSNCFromBytes(n.RawData()),
-		}, nil
+		return NewBufDagReader(n.RawData()), nil
 	case *mdag.ProtoNode:
 		pb := new(ftpb.Data)
 		if err := proto.Unmarshal(n.Data(), pb); err != nil {

unixfs/io/pbdagreader.go

@@ -45,6 +45,8 @@ type pbDagReader struct {
 	cancel func()
 }
 
+var _ DagReader = (*pbDagReader)(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)