core: update verified state root height

pkg/core/blockchain.go

@@ -1781,7 +1781,7 @@ func (bc *Blockchain) AddStateRoot(r *state.MPTRoot) error {
 	our, err := bc.GetStateRoot(r.Index)
 	if err == nil {
 		if our.Flag == state.Verified {
-			return nil
+			return bc.updateStateHeight(r.Index)
 		} else if r.Witness == nil && our.Witness != nil {
 			r.Witness = our.Witness
 		}
@@ -1803,10 +1803,24 @@ func (bc *Blockchain) AddStateRoot(r *state.MPTRoot) error {
 		}
 		flag = state.Verified
 	}
-	return bc.dao.PutStateRoot(&state.MPTRootState{
+	err = bc.dao.PutStateRoot(&state.MPTRootState{
 		MPTRoot: *r,
 		Flag:    flag,
 	})
+	if err != nil {
+		return err
+	}
+	return bc.updateStateHeight(r.Index)
+}
+
+func (bc *Blockchain) updateStateHeight(newHeight uint32) error {
+	h, err := bc.dao.GetCurrentStateRootHeight()
+	if err != nil {
+		return errors.WithMessage(err, "can't get current state root height")
+	} else if newHeight == h+1 {
+		return bc.dao.PutCurrentStateRootHeight(h + 1)
+	}
+	return nil
 }
 
 // verifyStateRoot checks if state root is valid.

pkg/core/dao/dao.go

@@ -32,6 +32,7 @@ type DAO interface {
 	GetContractState(hash util.Uint160) (*state.Contract, error)
 	GetCurrentBlockHeight() (uint32, error)
 	GetCurrentHeaderHeight() (i uint32, h util.Uint256, err error)
+	GetCurrentStateRootHeight() (uint32, error)
 	GetHeaderHashes() ([]util.Uint256, error)
 	GetNEP5Balances(acc util.Uint160) (*state.NEP5Balances, error)
 	GetNEP5TransferLog(acc util.Uint160, index uint32) (*state.NEP5TransferLog, error)
@@ -434,6 +435,27 @@ func (dao *Simple) InitMPT(height uint32) error {
 	return nil
 }
 
+// GetCurrentStateRootHeight returns current state root height.
+func (dao *Simple) GetCurrentStateRootHeight() (uint32, error) {
+	key := []byte{byte(storage.DataMPT)}
+	val, err := dao.Store.Get(key)
+	if err != nil {
+		if err == storage.ErrKeyNotFound {
+			err = nil
+		}
+		return 0, err
+	}
+	return binary.LittleEndian.Uint32(val), nil
+}
+
+// PutCurrentStateRootHeight updates current state root height.
+func (dao *Simple) PutCurrentStateRootHeight(height uint32) error {
+	key := []byte{byte(storage.DataMPT)}
+	val := make([]byte, 4)
+	binary.LittleEndian.PutUint32(val, height)
+	return dao.Store.Put(key, val)
+}
+
 // GetStateRoot returns state root of a given height.
 func (dao *Simple) GetStateRoot(height uint32) (*state.MPTRootState, error) {
 	r := new(state.MPTRootState)