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9.2 KiB

package statedb
import (
"math/big"
"github.com/hermeznetwork/hermez-node/common"
"github.com/iden3/go-iden3-crypto/poseidon"
"github.com/iden3/go-merkletree"
"github.com/iden3/go-merkletree/db"
"github.com/iden3/go-merkletree/db/memory"
)
// keyidx is used as key in the db to store the current Idx
var keyidx = []byte("idx")
// ProcessTxs process the given L1Txs & L2Txs applying the needed updates to
// the StateDB depending on the transaction Type. Returns the common.ZKInputs
// to generate the SnarkProof later used by the BatchBuilder, and if
// cmpExitTree is set to true, returns common.ExitTreeLeaf that is later used
// by the Synchronizer to update the HistoryDB.
func (s *StateDB) ProcessTxs(cmpExitTree bool, l1usertxs, l1coordinatortxs []*common.L1Tx, l2txs []*common.L2Tx) (*common.ZKInputs, []*common.ExitInfo, error) {
var err error
var exitTree *merkletree.MerkleTree
exits := make(map[common.Idx]common.Account)
// TBD if ExitTree is only in memory or stored in disk, for the moment
// only needed in memory
exitTree, err = merkletree.NewMerkleTree(memory.NewMemoryStorage(), s.mt.MaxLevels())
if err != nil {
return nil, nil, err
}
for _, tx := range l1coordinatortxs {
exitIdx, exitAccount, err := s.processL1Tx(exitTree, tx)
if err != nil {
return nil, nil, err
}
if exitIdx != nil && cmpExitTree {
exits[*exitIdx] = *exitAccount
}
}
for _, tx := range l1usertxs {
exitIdx, exitAccount, err := s.processL1Tx(exitTree, tx)
if err != nil {
return nil, nil, err
}
if exitIdx != nil && cmpExitTree {
exits[*exitIdx] = *exitAccount
}
}
for _, tx := range l2txs {
exitIdx, exitAccount, err := s.processL2Tx(exitTree, tx)
if err != nil {
return nil, nil, err
}
if exitIdx != nil && cmpExitTree {
exits[*exitIdx] = *exitAccount
}
}
if !cmpExitTree {
return nil, nil, nil
}
// once all txs processed (exitTree root frozen), for each leaf
// generate common.ExitInfo data
var exitInfos []*common.ExitInfo
for exitIdx, exitAccount := range exits {
// 0. generate MerkleProof
p, err := exitTree.GenerateCircomVerifierProof(exitIdx.BigInt(), nil)
if err != nil {
return nil, nil, err
}
// 1. compute nullifier
exitAccStateValue, err := exitAccount.HashValue()
if err != nil {
return nil, nil, err
}
nullifier, err := poseidon.Hash([]*big.Int{
exitAccStateValue,
big.NewInt(int64(s.currentBatch)),
exitTree.Root().BigInt(),
})
if err != nil {
return nil, nil, err
}
// 2. generate common.ExitInfo
ei := &common.ExitInfo{
AccountIdx: exitIdx,
MerkleProof: p,
Nullifier: nullifier,
Balance: exitAccount.Balance,
}
exitInfos = append(exitInfos, ei)
}
// return exitInfos, so Synchronizer will be able to store it into
// HistoryDB for the concrete BatchNum
return nil, exitInfos, nil
}
// processL1Tx process the given L1Tx applying the needed updates to the
// StateDB depending on the transaction Type.
func (s *StateDB) processL1Tx(exitTree *merkletree.MerkleTree, tx *common.L1Tx) (*common.Idx, *common.Account, error) {
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())
if err != nil {
return nil, nil, 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, err
}
case common.TxTypeDeposit:
// update balance of the MT account
err := s.applyDeposit(tx, false)
if err != nil {
return nil, nil, 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, err
}
case common.TxTypeCreateAccountDepositTransfer:
// add new account to the merkletree, update balance in MT account,
// update balance & nonce of sender & receiver
err := s.applyCreateAccount(tx)
if err != nil {
return nil, nil, err
}
err = s.applyTransfer(tx.Tx())
if err != nil {
return nil, nil, err
}
case common.TxTypeExit:
// execute exit flow
exitAccount, err := s.applyExit(exitTree, tx.Tx())
if err != nil {
return nil, nil, err
}
return &tx.FromIdx, exitAccount, nil
default:
}
return nil, nil, nil
}
// processL2Tx process the given L2Tx applying the needed updates to
// the StateDB depending on the transaction Type.
func (s *StateDB) processL2Tx(exitTree *merkletree.MerkleTree, tx *common.L2Tx) (*common.Idx, *common.Account, error) {
switch tx.Type {
case common.TxTypeTransfer:
// go to the MT account of sender and receiver, and update
// balance & nonce
err := s.applyTransfer(tx.Tx())
if err != nil {
return nil, nil, err
}
case common.TxTypeExit:
// execute exit flow
exitAccount, err := s.applyExit(exitTree, tx.Tx())
if err != nil {
return nil, nil, err
}
return &tx.FromIdx, exitAccount, nil
default:
}
return nil, nil, 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,
}
_, err := s.CreateAccount(common.Idx(s.idx+1), account)
if err != nil {
return err
}
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
if transfer {
accReceiver, err := s.GetAccount(tx.ToIdx)
if err != nil {
return err
}
// substract 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 receiver account in localStateDB
_, err = s.UpdateAccount(tx.ToIdx, accReceiver)
if err != nil {
return err
}
}
// update sender account in localStateDB
_, err = s.UpdateAccount(tx.FromIdx, accSender)
if err != nil {
return err
}
return nil
}
// applyTransfer updates the balance & nonce in the account of the sender, and
// the balance in the account of the receiver
func (s *StateDB) applyTransfer(tx *common.Tx) error {
// get sender and receiver accounts from localStateDB
accSender, err := s.GetAccount(tx.FromIdx)
if err != nil {
return err
}
accReceiver, err := s.GetAccount(tx.ToIdx)
if err != nil {
return err
}
// increment nonce
accSender.Nonce++
// substract 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 receiver account in localStateDB
_, err = s.UpdateAccount(tx.ToIdx, accReceiver)
if err != nil {
return err
}
// update sender account in localStateDB
_, err = s.UpdateAccount(tx.FromIdx, accSender)
if err != nil {
return err
}
return nil
}
func (s *StateDB) applyExit(exitTree *merkletree.MerkleTree, tx *common.Tx) (*common.Account, error) {
// 0. substract 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, err
}
acc.Balance = new(big.Int).Sub(acc.Balance, tx.Amount)
_, err = s.UpdateAccount(tx.FromIdx, acc)
if err != nil {
return nil, err
}
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, err
} else if err != nil {
return exitAccount, 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, 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
}
tx.Put(keyidx, idx.Bytes())
if err := tx.Commit(); err != nil {
return err
}
return nil
}