[#168] refs: Implement binary/JSON encoders/decoders on Signature

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>

v2/refs/json.go

@@ -104,3 +104,23 @@ func (v *Version) UnmarshalJSON(data []byte) error {
 
 	return nil
 }
+
+func (s *Signature) MarshalJSON() ([]byte, error) {
+	return protojson.MarshalOptions{
+		EmitUnpopulated: true,
+	}.Marshal(
+		SignatureToGRPCMessage(s),
+	)
+}
+
+func (s *Signature) UnmarshalJSON(data []byte) error {
+	msg := new(refs.Signature)
+
+	if err := protojson.Unmarshal(data, msg); err != nil {
+		return err
+	}
+
+	*s = *SignatureFromGRPCMessage(msg)
+
+	return nil
+}

v2/refs/json_test.go

@@ -69,3 +69,15 @@ func TestVersionSON(t *testing.T) {
 
 	require.Equal(t, v, v2)
 }
+
+func TestSignatureSON(t *testing.T) {
+	s := generateSignature("key", "sig")
+
+	data, err := s.MarshalJSON()
+	require.NoError(t, err)
+
+	s2 := new(refs.Signature)
+	require.NoError(t, s2.UnmarshalJSON(data))
+
+	require.Equal(t, s, s2)
+}

v2/refs/marshal.go

@@ -266,6 +266,17 @@ func (s *Signature) StableSize() (size int) {
 	return size
 }
 
+func (s *Signature) Unmarshal(data []byte) error {
+	m := new(refs.Signature)
+	if err := goproto.Unmarshal(data, m); err != nil {
+		return err
+	}
+
+	*s = *SignatureFromGRPCMessage(m)
+
+	return nil
+}
+
 func (v *Version) StableMarshal(buf []byte) ([]byte, error) {
 	if v == nil {
 		return []byte{}, nil

v2/refs/marshal_test.go

@@ -95,16 +95,14 @@ func TestChecksum_StableMarshal(t *testing.T) {
 
 func TestSignature_StableMarshal(t *testing.T) {
 	signatureFrom := generateSignature("Public Key", "Signature")
-	transport := new(grpc.Signature)
 
 	t.Run("non empty", func(t *testing.T) {
 		wire, err := signatureFrom.StableMarshal(nil)
 		require.NoError(t, err)
 
-		err = goproto.Unmarshal(wire, transport)
-		require.NoError(t, err)
+		signatureTo := new(refs.Signature)
+		require.NoError(t, signatureTo.Unmarshal(wire))
 
-		signatureTo := refs.SignatureFromGRPCMessage(transport)
 		require.Equal(t, signatureFrom, signatureTo)
 	})
 }