rpc/server: implement getstateheight RPC

pkg/rpc/response/result/mpt.go

@@ -0,0 +1,7 @@
+package result
+
+// StateHeight is a result of getstateheight RPC.
+type StateHeight struct {
+	BlockHeight uint32 `json:"blockHeight"`
+	StateHeight uint32 `json:"stateHeight"`
+}

pkg/rpc/server/server.go

@@ -95,6 +95,7 @@ var rpcHandlers = map[string]func(*Server, request.Params) (interface{}, *respon
 	"getpeers":             (*Server).getPeers,
 	"getrawmempool":        (*Server).getRawMempool,
 	"getrawtransaction":    (*Server).getrawtransaction,
+	"getstateheight":       (*Server).getStateHeight,
 	"getstateroot":         (*Server).getStateRoot,
 	"getstorage":           (*Server).getStorage,
 	"gettransactionheight": (*Server).getTransactionHeight,
@@ -688,6 +689,14 @@ func (s *Server) getDecimals(h util.Uint160, cache map[util.Uint160]int64) (int6
 	return d, nil
 }
 
+func (s *Server) getStateHeight(_ request.Params) (interface{}, *response.Error) {
+	height := s.chain.BlockHeight()
+	return &result.StateHeight{
+		BlockHeight: height,
+		StateHeight: height,
+	}, nil
+}
+
 func (s *Server) getStateRoot(ps request.Params) (interface{}, *response.Error) {
 	p := ps.Value(0)
 	if p == nil {

pkg/rpc/server/server_test.go

@@ -214,6 +214,21 @@ var rpcTestCases = map[string][]rpcTestCase{
 			},
 		},
 	},
+	"getstateheight": {
+		{
+			name:   "positive",
+			params: `[]`,
+			result: func(_ *executor) interface{} { return new(result.StateHeight) },
+			check: func(t *testing.T, e *executor, res interface{}) {
+				sh, ok := res.(*result.StateHeight)
+				require.True(t, ok)
+
+				h := e.chain.BlockHeight()
+				require.Equal(t, h, sh.BlockHeight)
+				require.Equal(t, h, sh.StateHeight)
+			},
+		},
+	},
 	"getstateroot": {
 		{
 			name:   "no params",