[#446] innerring: Add alphabet index getter in global state

Signed-off-by: Alex Vanin <alexey@nspcc.ru>

pkg/innerring/indexer.go

@@ -18,6 +18,7 @@ type innerRingIndexer struct {
 	timeout time.Duration
 
 	innerRingIndex, innerRingSize int32
+	alphabetIndex                 int32
 
 	lastAccess time.Time
 }
@@ -52,6 +53,11 @@ func (s *innerRingIndexer) update() (err error) {
 		return err
 	}
 
+	s.alphabetIndex, err = invoke.AlphabetIndex(s.cli, s.key)
+	if err != nil {
+		return err
+	}
+
 	s.lastAccess = time.Now()
 
 	return nil
@@ -78,3 +84,14 @@ func (s *innerRingIndexer) InnerRingSize() (int32, error) {
 
 	return s.innerRingSize, nil
 }
+
+func (s *innerRingIndexer) AlphabetIndex() (int32, error) {
+	if err := s.update(); err != nil {
+		return 0, errors.Wrap(err, "can't update index state")
+	}
+
+	s.RLock()
+	defer s.RUnlock()
+
+	return s.alphabetIndex, nil
+}

pkg/innerring/invoke/chain.go

@@ -25,6 +25,21 @@ func InnerRingIndex(cli *client.Client, key *ecdsa.PublicKey) (int32, int32, err
 	return keyPosition(key, innerRing), int32(len(innerRing)), nil
 }
 
+// AlphabetIndex returns index of the `key` in the alphabet key list from sidechain
+// If key is not in the inner ring list, then returns `-1` as index.
+func AlphabetIndex(cli *client.Client, key *ecdsa.PublicKey) (int32, error) {
+	if cli == nil {
+		return 0, client.ErrNilClient
+	}
+
+	alphabet, err := cli.Committee()
+	if err != nil {
+		return 0, err
+	}
+
+	return keyPosition(key, alphabet), nil
+}
+
 // keyPosition returns "-1" if key is not found in the list, otherwise returns
 // index of the key.
 func keyPosition(key *ecdsa.PublicKey, list keys.PublicKeys) (result int32) {

pkg/innerring/state.go

@@ -24,6 +24,11 @@ func (s *Server) IsActive() bool {
 	return s.InnerRingIndex() >= 0
 }
 
+// IsAlphabet is a getter for a global alphabet flag state.
+func (s *Server) IsAlphabet() bool {
+	return s.AlphabetIndex() >= 0
+}
+
 // InnerRingIndex is a getter for a global index of node in inner ring list. Negative
 // index means that node is not in the inner ring list.
 func (s *Server) InnerRingIndex() int {
@@ -48,6 +53,18 @@ func (s *Server) InnerRingSize() int {
 	return int(size)
 }
 
+// AlphabetIndex is a getter for a global index of node in alphabet list.
+// Negative index means that node is not in the alphabet list.
+func (s *Server) AlphabetIndex() int {
+	index, err := s.statusIndex.AlphabetIndex()
+	if err != nil {
+		s.log.Error("can't get alphabet index", zap.String("error", err.Error()))
+		return -1
+	}
+
+	return int(index)
+}
+
 func (s *Server) voteForSidechainValidator(validators []keys.PublicKey) error {
 	index := s.InnerRingIndex()
 	if s.contracts.alphabet.indexOutOfRange(index) {