using crypto.key as value and adding isLeaf() for readability

chain/chain.go

@@ -126,11 +126,11 @@ func (c Chain) Bytes() []byte {
 }
 
 func (c Chain) Invite(
-	invitersKey *crypto.Key,
+	invitersKey crypto.Key,
 	inviteesPubKey crypto.PubKey,
 	position int,
 ) (nc Chain) {
-	assert.D.True(invitersKey.PubKeyEqual(c.LeafPubKey()))
+	assert.D.True(c.isLeaf(invitersKey), "only left can ")
 
 	newBlock := Block{
 		HashToPrev:    c.hashToLeaf(),
@@ -144,6 +144,10 @@ func (c Chain) Invite(
 	return nc
 }
 
+func (c Chain) isLeaf(invitersKey crypto.Key) bool {
+	return invitersKey.PubKeyEqual(c.LeafPubKey())
+}
+
 func (c Chain) LeafPubKey() crypto.PubKey {
 	assert.D.True(len(c.Blocks) > 0)
 

chain/chain_test.go

@@ -10,11 +10,11 @@ import (
 
 var (
 	root, alice, bob struct {
-		*crypto.Key
+		crypto.Key
 		Chain
 	}
 	c                   Chain
-	rootKey, inviteeKey *crypto.Key
+	rootKey, inviteeKey crypto.Key
 )
 
 func TestMain(m *testing.M) {
@@ -87,7 +87,7 @@ func TestInvitation(t *testing.T) {
 	assert.True(t, bob.Verify())
 
 	cecilia := struct {
-		*crypto.Key
+		crypto.Key
 		Chain
 	}{
 		Key: crypto.NewKey(),
@@ -105,7 +105,7 @@ func TestInvitation(t *testing.T) {
 func TestCommonInviter(t *testing.T) {
 	// alice and bod have common root
 	cecilia := struct {
-		*crypto.Key
+		crypto.Key
 		Chain
 	}{
 		Key: crypto.NewKey(),
@@ -116,7 +116,7 @@ func TestCommonInviter(t *testing.T) {
 	assert.True(t, cecilia.Verify())
 
 	david := struct {
-		*crypto.Key
+		crypto.Key
 		Chain
 	}{
 		Key: crypto.NewKey(),
@@ -127,7 +127,7 @@ func TestCommonInviter(t *testing.T) {
 	assert.Equal(t, 0, CommonInviter(cecilia.Chain, david.Chain),
 		"cecilia and david have only common root")
 	edvin := struct {
-		*crypto.Key
+		crypto.Key
 		Chain
 	}{
 		Key: crypto.NewKey(),
@@ -152,7 +152,7 @@ func TestSameInviter(t *testing.T) {
 	assert.False(t, SameInviter(c, bob.Chain))
 
 	cecilia := struct {
-		*crypto.Key
+		crypto.Key
 		Chain
 	}{
 		Key: crypto.NewKey(),

crypto/crypto.go

@@ -22,10 +22,10 @@ type Key struct {
 	PubKey
 }
 
-func NewKey() *Key {
+func NewKey() Key {
 	pub, priv, err := ed25519.GenerateKey(nil)
 	err2.Check(err)
-	return &Key{PrivKey: priv, PubKey: pub}
+	return Key{PrivKey: priv, PubKey: pub}
 }
 
 func (k Key) PubKeyEqual(pubKey PubKey) bool {