Update to use new Builder interface for creating CIDs.

coding.go

@@ -93,10 +93,7 @@ func (n *ProtoNode) EncodeProtobuf(force bool) ([]byte, error) {
 	}
 
 	if n.cached == nil {
-		if n.Prefix.Codec == 0 { // unset
-			n.Prefix = v0CidPrefix
-		}
-		c, err := n.Prefix.Sum(n.encoded)
+		c, err := n.Prefix().Sum(n.encoded)
 		if err != nil {
 			return nil, err
 		}
@@ -134,7 +131,7 @@ func DecodeProtobufBlock(b blocks.Block) (ipld.Node, error) {
 	}
 
 	decnd.cached = c
-	decnd.Prefix = c.Prefix()
+	decnd.SetPrefix(c.Prefix())
 	return decnd, nil
 }
 

node.go

@@ -27,8 +27,8 @@ type ProtoNode struct {
 
 	cached *cid.Cid
 
-	// Prefix specifies cid version and hashing function
-	Prefix cid.Prefix
+	// builder specifies cid version and hashing function
+	builder cid.Builder
 }
 
 var v0CidPrefix = cid.Prefix{
@@ -63,14 +63,21 @@ func PrefixForCidVersion(version int) (cid.Prefix, error) {
 	}
 }
 
+// Prefix returns the CID Prefix for this ProtoNode, it is never nil
+func (n *ProtoNode) Prefix() cid.Builder {
+	if n.builder == nil {
+		n.builder = v0CidPrefix
+	}
+	return n.builder
+}
+
 // SetPrefix sets the CID prefix if it is non nil, if prefix is nil then
 // it resets it the default value
-func (n *ProtoNode) SetPrefix(prefix *cid.Prefix) {
+func (n *ProtoNode) SetPrefix(prefix cid.Builder) {
 	if prefix == nil {
-		n.Prefix = v0CidPrefix
+		n.builder = v0CidPrefix
 	} else {
-		n.Prefix = *prefix
-		n.Prefix.Codec = cid.DagProtobuf
+		n.builder = prefix.WithCodec(cid.DagProtobuf)
 		n.encoded = nil
 		n.cached = nil
 	}
@@ -191,7 +198,7 @@ func (n *ProtoNode) Copy() ipld.Node {
 		copy(nnode.links, n.links)
 	}
 
-	nnode.Prefix = n.Prefix
+	nnode.builder = n.builder
 
 	return nnode
 }
@@ -301,11 +308,7 @@ func (n *ProtoNode) Cid() *cid.Cid {
 		return n.cached
 	}
 
-	if n.Prefix.Codec == 0 {
-		n.SetPrefix(nil)
-	}
-
-	c, err := n.Prefix.Sum(n.RawData())
+	c, err := n.builder.Sum(n.RawData())
 	if err != nil {
 		// programmer error
 		err = fmt.Errorf("invalid CID of length %d: %x: %v", len(n.RawData()), n.RawData(), err)

raw.go

@@ -36,11 +36,8 @@ var _ ipld.DecodeBlockFunc = DecodeRawBlock
 
 // 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
-	}
+func NewRawNodeWPrefix(data []byte, prefix cid.Builder) (*RawNode, error) {
+	prefix = prefix.WithCodec(cid.Raw)
 	c, err := prefix.Sum(data)
 	if err != nil {
 		return nil, err