package statedb import ( "errors" "math/big" "github.com/hermeznetwork/hermez-node/common" "github.com/hermeznetwork/hermez-node/log" "github.com/iden3/go-iden3-crypto/babyjub" "github.com/iden3/go-merkletree" "github.com/iden3/go-merkletree/db" "github.com/iden3/go-merkletree/db/memory" ) var ( // keyidx is used as key in the db to store the current Idx keyidx = []byte("idx") ) func (s *StateDB) resetZKInputs() { s.zki = nil s.i = 0 } type processedExit struct { exit bool newExit bool idx common.Idx acc common.Account } // ProcessTxs process the given L1Txs & L2Txs applying the needed updates to // the StateDB depending on the transaction Type. If StateDB // type==TypeBatchBuilder, returns the common.ZKInputs to generate the // SnarkProof later used by the BatchBuilder. If StateDB // type==TypeSynchronizer, assumes that the call is done from the Synchronizer, // returns common.ExitTreeLeaf that is later used by the Synchronizer to update // the HistoryDB, and adds Nonce & TokenID to the L2Txs. func (s *StateDB) ProcessTxs(l1usertxs, l1coordinatortxs []*common.L1Tx, l2txs []*common.PoolL2Tx) (*common.ZKInputs, []common.ExitInfo, error) { var err error var exitTree *merkletree.MerkleTree if s.zki != nil { return nil, nil, errors.New("Expected StateDB.zki==nil, something went wrong and it's not empty") } defer s.resetZKInputs() nTx := len(l1usertxs) + len(l1coordinatortxs) + len(l2txs) if nTx == 0 { // TODO return ZKInputs of batch without txs return nil, nil, nil } exits := make([]processedExit, nTx) if s.typ == TypeBatchBuilder { s.zki = common.NewZKInputs(nTx, 24, 32) // TODO this values will be parameters of the function, taken from config file/coordinator call s.zki.OldLastIdx = (s.idx - 1).BigInt() s.zki.OldStateRoot = s.mt.Root().BigInt() } // TBD if ExitTree is only in memory or stored in disk, for the moment // only needed in memory if s.typ == TypeSynchronizer || s.typ == TypeBatchBuilder { exitTree, err = merkletree.NewMerkleTree(memory.NewMemoryStorage(), s.mt.MaxLevels()) if err != nil { return nil, nil, err } } // assumption: l1usertx are sorted by L1Tx.Position for _, tx := range l1usertxs { exitIdx, exitAccount, newExit, err := s.processL1Tx(exitTree, tx) if err != nil { return nil, nil, err } if s.typ == TypeSynchronizer || s.typ == TypeBatchBuilder { if exitIdx != nil && exitTree != nil { exits[s.i] = processedExit{ exit: true, newExit: newExit, idx: *exitIdx, acc: *exitAccount, } } s.i++ } } for _, tx := range l1coordinatortxs { exitIdx, exitAccount, newExit, err := s.processL1Tx(exitTree, tx) if err != nil { return nil, nil, err } if exitIdx != nil { log.Error("Unexpected Exit in L1CoordinatorTx") } if s.typ == TypeSynchronizer || s.typ == TypeBatchBuilder { if exitIdx != nil && exitTree != nil { exits[s.i] = processedExit{ exit: true, newExit: newExit, idx: *exitIdx, acc: *exitAccount, } } s.i++ } } for _, tx := range l2txs { exitIdx, exitAccount, newExit, err := s.processL2Tx(exitTree, tx) if err != nil { return nil, nil, err } if s.typ == TypeSynchronizer || s.typ == TypeBatchBuilder { if exitIdx != nil && exitTree != nil { exits[s.i] = processedExit{ exit: true, newExit: newExit, idx: *exitIdx, acc: *exitAccount, } } s.i++ } } if s.typ == TypeTxSelector { return nil, nil, nil } // once all txs processed (exitTree root frozen), for each Exit, // generate common.ExitInfo data var exitInfos []common.ExitInfo for i := 0; i < nTx; i++ { if !exits[i].exit { continue } exitIdx := exits[i].idx exitAccount := exits[i].acc // 0. generate MerkleProof p, err := exitTree.GenerateCircomVerifierProof(exitIdx.BigInt(), nil) if err != nil { return nil, nil, err } // 1. generate common.ExitInfo ei := common.ExitInfo{ AccountIdx: exitIdx, MerkleProof: p, Balance: exitAccount.Balance, } exitInfos = append(exitInfos, ei) if s.zki != nil { s.zki.TokenID2[i] = exitAccount.TokenID.BigInt() s.zki.Nonce2[i] = exitAccount.Nonce.BigInt() if babyjub.PointCoordSign(exitAccount.PublicKey.X) { s.zki.Sign2[i] = big.NewInt(1) } s.zki.Ay2[i] = exitAccount.PublicKey.Y s.zki.Balance2[i] = exitAccount.Balance s.zki.EthAddr2[i] = common.EthAddrToBigInt(exitAccount.EthAddr) s.zki.Siblings2[i] = p.Siblings if exits[i].newExit { s.zki.NewExit[i] = big.NewInt(1) } if p.IsOld0 { s.zki.IsOld0_2[i] = big.NewInt(1) } s.zki.OldKey2[i] = p.OldKey.BigInt() s.zki.OldValue2[i] = p.OldValue.BigInt() } } if s.typ == TypeSynchronizer { return nil, exitInfos, nil } // compute last ZKInputs parameters s.zki.GlobalChainID = big.NewInt(0) // TODO, 0: ethereum, this will be get from config file // zki.FeeIdxs = ? // TODO, this will be get from the config file tokenIDs, err := s.getTokenIDsBigInt(l1usertxs, l1coordinatortxs, l2txs) if err != nil { return nil, nil, err } s.zki.FeePlanTokens = tokenIDs // s.zki.ISInitStateRootFee = s.mt.Root().BigInt() // TODO once the Node Config sets the Accounts where to send the Fees // compute fees & update ZKInputs // return exitInfos, so Synchronizer will be able to store it into // HistoryDB for the concrete BatchNum return s.zki, exitInfos, nil } // getTokenIDsBigInt returns the list of TokenIDs in *big.Int format func (s *StateDB) getTokenIDsBigInt(l1usertxs, l1coordinatortxs []*common.L1Tx, l2txs []*common.PoolL2Tx) ([]*big.Int, error) { tokenIDs := make(map[common.TokenID]bool) for i := 0; i < len(l1usertxs); i++ { tokenIDs[l1usertxs[i].TokenID] = true } for i := 0; i < len(l1coordinatortxs); i++ { tokenIDs[l1coordinatortxs[i].TokenID] = true } for i := 0; i < len(l2txs); i++ { // as L2Tx does not have parameter TokenID, get it from the // AccountsDB (in the StateDB) acc, err := s.GetAccount(l2txs[i].ToIdx) if err != nil { return nil, err } tokenIDs[acc.TokenID] = true } var tBI []*big.Int for t := range tokenIDs { tBI = append(tBI, t.BigInt()) } return tBI, nil } // processL1Tx process the given L1Tx applying the needed updates to the // StateDB depending on the transaction Type. It returns the 3 parameters // related to the Exit (in case of): Idx, ExitAccount, boolean determining if // the Exit created a new Leaf in the ExitTree. func (s *StateDB) processL1Tx(exitTree *merkletree.MerkleTree, tx *common.L1Tx) (*common.Idx, *common.Account, bool, error) { // ZKInputs if s.zki != nil { // Txs // s.zki.TxCompressedData[s.i] = tx.TxCompressedData() // uncomment once L1Tx.TxCompressedData is ready if tx.FromIdx != nil { s.zki.FromIdx[s.i] = tx.FromIdx.BigInt() } else { s.zki.FromIdx[s.i] = big.NewInt(0) } s.zki.ToIdx[s.i] = tx.ToIdx.BigInt() s.zki.OnChain[s.i] = big.NewInt(1) // L1Txs s.zki.LoadAmountF[s.i] = tx.LoadAmount s.zki.FromEthAddr[s.i] = common.EthAddrToBigInt(tx.FromEthAddr) if tx.FromBJJ != nil { s.zki.FromBJJCompressed[s.i] = BJJCompressedTo256BigInts(tx.FromBJJ.Compress()) } // Intermediate States s.zki.ISOnChain[s.i] = big.NewInt(1) } switch tx.Type { case common.TxTypeForceTransfer, common.TxTypeTransfer: // go to the MT account of sender and receiver, and update balance // & nonce err := s.applyTransfer(tx.Tx(), 0) // 0 for the parameter toIdx, as at L1Tx ToIdx can only be 0 in the Deposit type case. if err != nil { return nil, nil, false, err } case common.TxTypeCreateAccountDeposit: // add new account to the MT, update balance of the MT account err := s.applyCreateAccount(tx) if err != nil { return nil, nil, false, err } if s.zki != nil { s.zki.AuxFromIdx[s.i] = s.idx.BigInt() // last s.idx is the one used for creating the new account s.zki.NewAccount[s.i] = big.NewInt(1) } case common.TxTypeDeposit: // update balance of the MT account err := s.applyDeposit(tx, false) if err != nil { return nil, nil, false, err } case common.TxTypeDepositTransfer: // update balance in MT account, update balance & nonce of sender // & receiver err := s.applyDeposit(tx, true) if err != nil { return nil, nil, false, err } case common.TxTypeCreateAccountDepositTransfer: // add new account to the merkletree, update balance in MT account, // update balance & nonce of sender & receiver err := s.applyCreateAccountDepositTransfer(tx) if err != nil { return nil, nil, false, err } if s.zki != nil { s.zki.AuxFromIdx[s.i] = s.idx.BigInt() // last s.idx is the one used for creating the new account s.zki.NewAccount[s.i] = big.NewInt(1) } case common.TxTypeExit: // execute exit flow exitAccount, newExit, err := s.applyExit(exitTree, tx.Tx()) if err != nil { return nil, nil, false, err } return tx.FromIdx, exitAccount, newExit, nil default: } return nil, nil, false, nil } // processL2Tx process the given L2Tx applying the needed updates to the // StateDB depending on the transaction Type. It returns the 3 parameters // related to the Exit (in case of): Idx, ExitAccount, boolean determining if // the Exit created a new Leaf in the ExitTree. func (s *StateDB) processL2Tx(exitTree *merkletree.MerkleTree, tx *common.PoolL2Tx) (*common.Idx, *common.Account, bool, error) { var err error var auxToIdx common.Idx // if tx.ToIdx==0, get toIdx by ToEthAddr or ToBJJ if tx.ToIdx == nil || *tx.ToIdx == common.Idx(0) { auxToIdx, err = s.GetIdxByEthAddrBJJ(tx.ToEthAddr, tx.ToBJJ) if err != nil { log.Error(err) return nil, nil, false, err } } // ZKInputs if s.zki != nil { // Txs // s.zki.TxCompressedData[s.i] = tx.TxCompressedData() // uncomment once L1Tx.TxCompressedData is ready // s.zki.TxCompressedDataV2[s.i] = tx.TxCompressedDataV2() // uncomment once L2Tx.TxCompressedDataV2 is ready s.zki.FromIdx[s.i] = tx.FromIdx.BigInt() s.zki.ToIdx[s.i] = tx.ToIdx.BigInt() // fill AuxToIdx if needed if tx.ToIdx == nil { // use toIdx that can have been filled by tx.ToIdx or // if tx.Idx==0 (this case), toIdx is filled by the Idx // from db by ToEthAddr&ToBJJ s.zki.AuxToIdx[s.i] = auxToIdx.BigInt() } s.zki.ToBJJAy[s.i] = tx.ToBJJ.Y if tx.ToEthAddr != nil { s.zki.ToEthAddr[s.i] = common.EthAddrToBigInt(*tx.ToEthAddr) } else { // Not sure if this should throw an error s.zki.ToEthAddr[s.i] = big.NewInt(0) } s.zki.OnChain[s.i] = big.NewInt(0) s.zki.NewAccount[s.i] = big.NewInt(0) // L2Txs // s.zki.RqOffset[s.i] = // TODO Rq once TxSelector is ready // s.zki.RqTxCompressedDataV2[s.i] = // TODO // s.zki.RqToEthAddr[s.i] = common.EthAddrToBigInt(tx.RqToEthAddr) // TODO // s.zki.RqToBJJAy[s.i] = tx.ToBJJ.Y // TODO s.zki.S[s.i] = tx.Signature.S s.zki.R8x[s.i] = tx.Signature.R8.X s.zki.R8y[s.i] = tx.Signature.R8.Y } // if StateDB type==TypeSynchronizer, will need to add Nonce and // TokenID to the transaction if s.typ == TypeSynchronizer { acc, err := s.GetAccount(tx.ToIdx) if err != nil { return nil, nil, false, err } tx.Nonce = acc.Nonce tx.TokenID = acc.TokenID } switch tx.Type { case common.TxTypeTransfer: // go to the MT account of sender and receiver, and update // balance & nonce tmpTx, err := tx.Tx() if err != nil { return nil, nil, false, err } err = s.applyTransfer(tmpTx, auxToIdx) if err != nil { return nil, nil, false, err } case common.TxTypeExit: // execute exit flow tmpTx, err := tx.Tx() if err != nil { return nil, nil, false, err } exitAccount, newExit, err := s.applyExit(exitTree, tmpTx) if err != nil { return nil, nil, false, err } return &tx.FromIdx, exitAccount, newExit, nil default: } return nil, nil, false, nil } // applyCreateAccount creates a new account in the account of the depositer, it // stores the deposit value func (s *StateDB) applyCreateAccount(tx *common.L1Tx) error { account := &common.Account{ TokenID: tx.TokenID, Nonce: 0, Balance: tx.LoadAmount, PublicKey: tx.FromBJJ, EthAddr: tx.FromEthAddr, } p, err := s.CreateAccount(common.Idx(s.idx+1), account) if err != nil { return err } if s.zki != nil { s.zki.TokenID1[s.i] = tx.TokenID.BigInt() s.zki.Nonce1[s.i] = big.NewInt(0) if babyjub.PointCoordSign(tx.FromBJJ.X) { s.zki.Sign1[s.i] = big.NewInt(1) } s.zki.Ay1[s.i] = tx.FromBJJ.Y s.zki.Balance1[s.i] = tx.LoadAmount s.zki.EthAddr1[s.i] = common.EthAddrToBigInt(tx.FromEthAddr) s.zki.Siblings1[s.i] = siblingsToZKInputFormat(p.Siblings) if p.IsOld0 { s.zki.IsOld0_1[s.i] = big.NewInt(1) } s.zki.OldKey1[s.i] = p.OldKey.BigInt() s.zki.OldValue1[s.i] = p.OldValue.BigInt() } s.idx = s.idx + 1 return s.setIdx(s.idx) } // applyDeposit updates the balance in the account of the depositer, if // andTransfer parameter is set to true, the method will also apply the // Transfer of the L1Tx/DepositTransfer func (s *StateDB) applyDeposit(tx *common.L1Tx, transfer bool) error { // deposit the tx.LoadAmount into the sender account accSender, err := s.GetAccount(tx.FromIdx) if err != nil { return err } accSender.Balance = new(big.Int).Add(accSender.Balance, tx.LoadAmount) // in case that the tx is a L1Tx>DepositTransfer var accReceiver *common.Account if transfer { accReceiver, err = s.GetAccount(&tx.ToIdx) if err != nil { return err } // subtract amount to the sender accSender.Balance = new(big.Int).Sub(accSender.Balance, tx.Amount) // add amount to the receiver accReceiver.Balance = new(big.Int).Add(accReceiver.Balance, tx.Amount) } // update sender account in localStateDB p, err := s.UpdateAccount(tx.FromIdx, accSender) if err != nil { return err } if s.zki != nil { s.zki.TokenID1[s.i] = accSender.TokenID.BigInt() s.zki.Nonce1[s.i] = accSender.Nonce.BigInt() if babyjub.PointCoordSign(accSender.PublicKey.X) { s.zki.Sign1[s.i] = big.NewInt(1) } s.zki.Ay1[s.i] = accSender.PublicKey.Y s.zki.Balance1[s.i] = accSender.Balance s.zki.EthAddr1[s.i] = common.EthAddrToBigInt(accSender.EthAddr) s.zki.Siblings1[s.i] = siblingsToZKInputFormat(p.Siblings) // IsOld0_1, OldKey1, OldValue1 not needed as this is not an insert } // this is done after updating Sender Account (depositer) if transfer { // update receiver account in localStateDB p, err := s.UpdateAccount(&tx.ToIdx, accReceiver) if err != nil { return err } if s.zki != nil { s.zki.TokenID2[s.i] = accReceiver.TokenID.BigInt() s.zki.Nonce2[s.i] = accReceiver.Nonce.BigInt() if babyjub.PointCoordSign(accReceiver.PublicKey.X) { s.zki.Sign2[s.i] = big.NewInt(1) } s.zki.Ay2[s.i] = accReceiver.PublicKey.Y s.zki.Balance2[s.i] = accReceiver.Balance s.zki.EthAddr2[s.i] = common.EthAddrToBigInt(accReceiver.EthAddr) s.zki.Siblings2[s.i] = siblingsToZKInputFormat(p.Siblings) // IsOld0_2, OldKey2, OldValue2 not needed as this is not an insert } } return nil } // applyTransfer updates the balance & nonce in the account of the sender, and // the balance in the account of the receiver. // Parameter 'toIdx' should be at 0 if the tx already has tx.ToIdx!=0, if // tx.ToIdx==0, then toIdx!=0, and will be used the toIdx parameter as Idx of // the receiver. This parameter is used when the tx.ToIdx is not specified and // the real ToIdx is found trhrough the ToEthAddr or ToBJJ. func (s *StateDB) applyTransfer(tx *common.Tx, auxToIdx common.Idx) error { if auxToIdx == 0 { if tx.ToIdx == nil { return errors.New("tx.ToIdx cannot be nil if auxToIdx is 0") } auxToIdx = *tx.ToIdx } // get sender and receiver accounts from localStateDB accSender, err := s.GetAccount(tx.FromIdx) if err != nil { return err } accReceiver, err := s.GetAccount(&auxToIdx) if err != nil { return err } // increment nonce accSender.Nonce++ // subtract amount to the sender accSender.Balance = new(big.Int).Sub(accSender.Balance, tx.Amount) // add amount to the receiver accReceiver.Balance = new(big.Int).Add(accReceiver.Balance, tx.Amount) // update sender account in localStateDB pSender, err := s.UpdateAccount(tx.FromIdx, accSender) if err != nil { return err } if s.zki != nil { s.zki.TokenID1[s.i] = accSender.TokenID.BigInt() s.zki.Nonce1[s.i] = accSender.Nonce.BigInt() if babyjub.PointCoordSign(accSender.PublicKey.X) { s.zki.Sign1[s.i] = big.NewInt(1) } s.zki.Ay1[s.i] = accSender.PublicKey.Y s.zki.Balance1[s.i] = accSender.Balance s.zki.EthAddr1[s.i] = common.EthAddrToBigInt(accSender.EthAddr) s.zki.Siblings1[s.i] = siblingsToZKInputFormat(pSender.Siblings) } // update receiver account in localStateDB pReceiver, err := s.UpdateAccount(&auxToIdx, accReceiver) if err != nil { return err } if s.zki != nil { s.zki.TokenID2[s.i] = accReceiver.TokenID.BigInt() s.zki.Nonce2[s.i] = accReceiver.Nonce.BigInt() if babyjub.PointCoordSign(accReceiver.PublicKey.X) { s.zki.Sign2[s.i] = big.NewInt(1) } s.zki.Ay2[s.i] = accReceiver.PublicKey.Y s.zki.Balance2[s.i] = accReceiver.Balance s.zki.EthAddr2[s.i] = common.EthAddrToBigInt(accReceiver.EthAddr) s.zki.Siblings2[s.i] = siblingsToZKInputFormat(pReceiver.Siblings) } return nil } // applyCreateAccountDepositTransfer, in a single tx, creates a new account, // makes a deposit, and performs a transfer to another account func (s *StateDB) applyCreateAccountDepositTransfer(tx *common.L1Tx) error { accSender := &common.Account{ TokenID: tx.TokenID, Nonce: 0, Balance: tx.LoadAmount, PublicKey: tx.FromBJJ, EthAddr: tx.FromEthAddr, } accSender.Balance = new(big.Int).Add(accSender.Balance, tx.LoadAmount) accReceiver, err := s.GetAccount(&tx.ToIdx) if err != nil { return err } // subtract amount to the sender accSender.Balance = new(big.Int).Sub(accSender.Balance, tx.Amount) // add amount to the receiver accReceiver.Balance = new(big.Int).Add(accReceiver.Balance, tx.Amount) // create Account of the Sender p, err := s.CreateAccount(common.Idx(s.idx+1), accSender) if err != nil { return err } if s.zki != nil { s.zki.TokenID1[s.i] = tx.TokenID.BigInt() s.zki.Nonce1[s.i] = big.NewInt(0) if babyjub.PointCoordSign(tx.FromBJJ.X) { s.zki.Sign1[s.i] = big.NewInt(1) } s.zki.Ay1[s.i] = tx.FromBJJ.Y s.zki.Balance1[s.i] = tx.LoadAmount s.zki.EthAddr1[s.i] = common.EthAddrToBigInt(tx.FromEthAddr) s.zki.Siblings1[s.i] = siblingsToZKInputFormat(p.Siblings) if p.IsOld0 { s.zki.IsOld0_1[s.i] = big.NewInt(1) } s.zki.OldKey1[s.i] = p.OldKey.BigInt() s.zki.OldValue1[s.i] = p.OldValue.BigInt() } // update receiver account in localStateDB p, err = s.UpdateAccount(&tx.ToIdx, accReceiver) if err != nil { return err } if s.zki != nil { s.zki.TokenID2[s.i] = accReceiver.TokenID.BigInt() s.zki.Nonce2[s.i] = accReceiver.Nonce.BigInt() if babyjub.PointCoordSign(accReceiver.PublicKey.X) { s.zki.Sign2[s.i] = big.NewInt(1) } s.zki.Ay2[s.i] = accReceiver.PublicKey.Y s.zki.Balance2[s.i] = accReceiver.Balance s.zki.EthAddr2[s.i] = common.EthAddrToBigInt(accReceiver.EthAddr) s.zki.Siblings2[s.i] = siblingsToZKInputFormat(p.Siblings) } s.idx = s.idx + 1 return s.setIdx(s.idx) } // It returns the ExitAccount and a boolean determining if the Exit created a // new Leaf in the ExitTree. func (s *StateDB) applyExit(exitTree *merkletree.MerkleTree, tx *common.Tx) (*common.Account, bool, error) { // 0. subtract tx.Amount from current Account in StateMT // add the tx.Amount into the Account (tx.FromIdx) in the ExitMT acc, err := s.GetAccount(tx.FromIdx) if err != nil { return nil, false, err } acc.Balance = new(big.Int).Sub(acc.Balance, tx.Amount) p, err := s.UpdateAccount(tx.FromIdx, acc) if err != nil { return nil, false, err } if s.zki != nil { s.zki.TokenID1[s.i] = acc.TokenID.BigInt() s.zki.Nonce1[s.i] = acc.Nonce.BigInt() if babyjub.PointCoordSign(acc.PublicKey.X) { s.zki.Sign1[s.i] = big.NewInt(1) } s.zki.Ay1[s.i] = acc.PublicKey.Y s.zki.Balance1[s.i] = acc.Balance s.zki.EthAddr1[s.i] = common.EthAddrToBigInt(acc.EthAddr) s.zki.Siblings1[s.i] = siblingsToZKInputFormat(p.Siblings) } if exitTree == nil { return nil, false, nil } exitAccount, err := getAccountInTreeDB(exitTree.DB(), tx.FromIdx) if err == db.ErrNotFound { // 1a. if idx does not exist in exitTree: // add new leaf 'ExitTreeLeaf', where ExitTreeLeaf.Balance = exitAmount (exitAmount=tx.Amount) exitAccount := &common.Account{ TokenID: acc.TokenID, Nonce: common.Nonce(1), Balance: tx.Amount, PublicKey: acc.PublicKey, EthAddr: acc.EthAddr, } _, err = createAccountInTreeDB(exitTree.DB(), exitTree, tx.FromIdx, exitAccount) return exitAccount, true, err } else if err != nil { return exitAccount, false, err } // 1b. if idx already exist in exitTree: // update account, where account.Balance += exitAmount exitAccount.Balance = new(big.Int).Add(exitAccount.Balance, tx.Amount) _, err = updateAccountInTreeDB(exitTree.DB(), exitTree, tx.FromIdx, exitAccount) return exitAccount, false, err } // getIdx returns the stored Idx from the localStateDB, which is the last Idx // used for an Account in the localStateDB. func (s *StateDB) getIdx() (common.Idx, error) { idxBytes, err := s.DB().Get(keyidx) if err == db.ErrNotFound { return 0, nil } if err != nil { return 0, err } return common.IdxFromBytes(idxBytes[:4]) } // setIdx stores Idx in the localStateDB func (s *StateDB) setIdx(idx common.Idx) error { tx, err := s.DB().NewTx() if err != nil { return err } idxBytes, err := idx.Bytes() if err != nil { return err } err = tx.Put(keyidx, idxBytes[:]) if err != nil { return err } if err := tx.Commit(); err != nil { return err } return nil }