[viewchange] rename NextAfter to NthNext

The NthNext will return the nth key after the current pubkey

Signed-off-by: Leo Chen <leo@harmony.one>

consensus/quorum/quorum.go

@@ -72,7 +72,7 @@ type ParticipantTracker interface {
 	Participants() multibls.PublicKeys
 	IndexOf(bls.SerializedPublicKey) int
 	ParticipantsCount() int64
-	NextAfter(*bls.PublicKeyWrapper, int) (bool, *bls.PublicKeyWrapper)
+	NthNext(*bls.PublicKeyWrapper, int) (bool, *bls.PublicKeyWrapper)
 	UpdateParticipants(pubKeys []bls.PublicKeyWrapper)
 }
 
@@ -187,8 +187,8 @@ func (s *cIdentities) IndexOf(pubKey bls.SerializedPublicKey) int {
 	return -1
 }
 
-// NextAfter return the next pubkey, next can be negative number
-func (s *cIdentities) NextAfter(pubKey *bls.PublicKeyWrapper, next int) (bool, *bls.PublicKeyWrapper) {
+// NthNext return the Nth next pubkey, next can be negative number
+func (s *cIdentities) NthNext(pubKey *bls.PublicKeyWrapper, next int) (bool, *bls.PublicKeyWrapper) {
 	found := false
 
 	idx := s.IndexOf(pubKey.Bytes)

consensus/view_change.go

@@ -98,7 +98,7 @@ func (consensus *Consensus) GetNextLeaderKey(viewID uint64) *bls.PublicKeyWrappe
 		Uint64("newViewID", viewID).
 		Uint64("myCurBlockViewID", consensus.GetCurBlockViewID()).
 		Msg("[GetNextLeaderKey] got leaderPubKey from coinbase")
-	wasFound, next := consensus.Decider.NextAfter(consensus.LeaderPubKey, gap)
+	wasFound, next := consensus.Decider.NthNext(consensus.LeaderPubKey, gap)
 	if !wasFound {
 		consensus.getLogger().Warn().
 			Str("key", consensus.LeaderPubKey.Bytes.Hex()).