merkeldag: change CidVersion from a struct to a uint64

Slightly less safe, but more idiomatic.

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

merkledag/cidversion.go

@@ -4,25 +4,20 @@ import (
 	"fmt"
 )
 
-// CidVersion is a a cid version number that is guaranteed to be valid
-type CidVersion struct {
-	version uint64
-}
+// CidVersion is a a cid version number.  Do not set directly, instead
+// use NewCidVersion to create.  It is safe to panic if it is invalid.
+type CidVersion uint64
 
-var (
-	CID0 = CidVersion{0}
-	CID1 = CidVersion{1}
+const (
+	CID0 CidVersion = 0
+	CID1 CidVersion = 1
 )
 
 func NewCidVersion(version int) (CidVersion, error) {
 	switch version {
 	case 0, 1:
-		return CidVersion{uint64(version)}, nil
+		return CidVersion(version), nil
 	default:
-		return CidVersion{}, fmt.Errorf("unknown CID version: %d", version)
+		return CidVersion(0), fmt.Errorf("unknown CID version: %d", version)
 	}
 }
-
-func (v CidVersion) Version() uint64 {
-	return v.version
-}

merkledag/node.go

@@ -43,7 +43,7 @@ var v1CidPrefix = cid.Prefix{
 }
 
 func (n *ProtoNode) SetCidVersion(v CidVersion) {
-	switch v := v.Version(); v {
+	switch v {
 	case 0:
 		n.Prefix = v0CidPrefix
 	case 1: