Add support for using an alternative hash function with raw nodes.

License: MIT
Signed-off-by: Kevin Atkinson <k@kevina.org>

merkledag.go

@@ -116,7 +116,7 @@ func decodeBlock(b blocks.Block) (node.Node, error) {
 		decnd.Prefix = b.Cid().Prefix()
 		return decnd, nil
 	case cid.Raw:
-		return NewRawNode(b.RawData()), nil
+		return NewRawNodeWPrefix(b.RawData(), b.Cid().Prefix())
 	case cid.DagCBOR:
 		return ipldcbor.Decode(b.RawData())
 	default:

raw.go

@@ -12,6 +12,8 @@ type RawNode struct {
 	blocks.Block
 }
 
+// NewRawNode creates a RawNode using the default sha2-256 hash
+// funcition.
 func NewRawNode(data []byte) *RawNode {
 	h := u.Hash(data)
 	c := cid.NewCidV1(cid.Raw, h)
@@ -20,6 +22,24 @@ func NewRawNode(data []byte) *RawNode {
 	return &RawNode{blk}
 }
 
+// NewRawNodeWPrefix creates a RawNode with the hash function
+// specified in prefix.
+func NewRawNodeWPrefix(data []byte, prefix cid.Prefix) (*RawNode, error) {
+	prefix.Codec = cid.Raw
+	if prefix.Version == 0 {
+		prefix.Version = 1
+	}
+	c, err := prefix.Sum(data)
+	if err != nil {
+		return nil, err
+	}
+	blk, err := blocks.NewBlockWithCid(data, c)
+	if err != nil {
+		return nil, err
+	}
+	return &RawNode{blk}, nil
+}
+
 func (rn *RawNode) Links() []*node.Link {
 	return nil
 }