From 53dc7f27b60ea6735e0b414de914abcd69432c08 Mon Sep 17 00:00:00 2001
From: Evgenii Stratonikov <evgeniy@nspcc.ru>
Date: Wed, 3 Jun 2020 18:09:36 +0300
Subject: [PATCH] rpc/server: implement getstateroot RPC

---
 pkg/rpc/server/server.go      | 23 +++++++++++++++++++++++
 pkg/rpc/server/server_test.go | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+)

diff --git a/pkg/rpc/server/server.go b/pkg/rpc/server/server.go
index e3703398c..b38129bb1 100644
--- a/pkg/rpc/server/server.go
+++ b/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,
+	"getstateroot":         (*Server).getStateRoot,
 	"getstorage":           (*Server).getStorage,
 	"gettransactionheight": (*Server).getTransactionHeight,
 	"gettxout":             (*Server).getTxOut,
@@ -687,6 +688,28 @@ func (s *Server) getDecimals(h util.Uint160, cache map[util.Uint160]int64) (int6
 	return d, nil
 }
 
+func (s *Server) getStateRoot(ps request.Params) (interface{}, *response.Error) {
+	p := ps.Value(0)
+	if p == nil {
+		return nil, response.NewRPCError("Invalid parameter.", "", nil)
+	}
+	var rt *state.MPTRootState
+	var h util.Uint256
+	height, err := p.GetInt()
+	if err == nil {
+		rt, err = s.chain.GetStateRoot(uint32(height))
+	} else if h, err = p.GetUint256(); err == nil {
+		hdr, err := s.chain.GetHeader(h)
+		if err == nil {
+			rt, err = s.chain.GetStateRoot(hdr.Index)
+		}
+	}
+	if err != nil {
+		return nil, response.NewRPCError("Unknown state root.", "", err)
+	}
+	return rt, nil
+}
+
 func (s *Server) getStorage(ps request.Params) (interface{}, *response.Error) {
 	scriptHash, err := ps.Value(0).GetUint160FromHex()
 	if err != nil {
diff --git a/pkg/rpc/server/server_test.go b/pkg/rpc/server/server_test.go
index 6103156f7..c6d384f80 100644
--- a/pkg/rpc/server/server_test.go
+++ b/pkg/rpc/server/server_test.go
@@ -16,6 +16,7 @@ import (
 
 	"github.com/gorilla/websocket"
 	"github.com/nspcc-dev/neo-go/pkg/core"
+	"github.com/nspcc-dev/neo-go/pkg/core/state"
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
 	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
 	"github.com/nspcc-dev/neo-go/pkg/encoding/address"
@@ -213,6 +214,18 @@ var rpcTestCases = map[string][]rpcTestCase{
 			},
 		},
 	},
+	"getstateroot": {
+		{
+			name:   "no params",
+			params: `[]`,
+			fail:   true,
+		},
+		{
+			name:   "invalid hash",
+			params: `["0x1234567890"]`,
+			fail:   true,
+		},
+	},
 	"getstorage": {
 		{
 			name:   "positive",
@@ -928,6 +941,25 @@ func testRPCProtocol(t *testing.T, doRPCCall func(string, string, *testing.T) []
 		})
 	}
 
+	t.Run("getstateroot", func(t *testing.T) {
+		testRoot := func(t *testing.T, p string) {
+			rpc := fmt.Sprintf(`{"jsonrpc": "2.0", "id": 1, "method": "getstateroot", "params": [%s]}`, p)
+			fmt.Println(rpc)
+			body := doRPCCall(rpc, httpSrv.URL, t)
+			rawRes := checkErrGetResult(t, body, false)
+
+			res := new(state.MPTRootState)
+			require.NoError(t, json.Unmarshal(rawRes, res))
+			require.NotEqual(t, util.Uint256{}, res.Root) // be sure this test uses valid height
+
+			expected, err := e.chain.GetStateRoot(205)
+			require.NoError(t, err)
+			require.Equal(t, expected, res)
+		}
+		t.Run("ByHeight", func(t *testing.T) { testRoot(t, strconv.FormatInt(205, 10)) })
+		t.Run("ByHash", func(t *testing.T) { testRoot(t, `"`+chain.GetHeaderHash(205).StringLE()+`"`) })
+	})
+
 	t.Run("getrawtransaction", func(t *testing.T) {
 		block, _ := chain.GetBlock(chain.GetHeaderHash(0))
 		TXHash := block.Transactions[1].Hash()