Migrate TxProcessors from BatchBuilder to StateDB

Migrate TxProcessors from BatchBuilder to StateDB in order to be used by
BatchBuilder & Synchronizer

db/statedb/statedb.go

@@ -34,6 +34,8 @@ type StateDB struct {
 	currentBatch uint64
 	db           *pebble.PebbleStorage
 	mt           *merkletree.MerkleTree
+	// idx holds the current Idx that the BatchBuilder is using
+	idx uint64
 }
 
 // NewStateDB creates a new StateDB, allowing to use an in-memory or in-disk
@@ -147,6 +149,11 @@ func (s *StateDB) DeleteCheckpoint(batchNum uint64) error {
 // those checkpoints will remain in the storage, and eventually will be
 // deleted when MakeCheckpoint overwrites them.
 func (s *StateDB) Reset(batchNum uint64) error {
+	if batchNum == 0 {
+		s.idx = 0
+		return nil
+	}
+
 	checkpointPath := s.path + PATHBATCHNUM + strconv.Itoa(int(batchNum))
 	currentPath := s.path + PATHCURRENT
 
@@ -174,7 +181,9 @@ func (s *StateDB) Reset(batchNum uint64) error {
 	if err != nil {
 		return err
 	}
-	return nil
+	// idx is obtained from the statedb reset
+	s.idx, err = s.getIdx()
+	return err
 }
 
 // GetAccount returns the account for the given Idx
@@ -315,6 +324,10 @@ func NewLocalStateDB(path string, synchronizerDB *StateDB, withMT bool, nLevels
 // Reset performs a reset in the LocaStateDB. If fromSynchronizer is true, it
 // gets the state from LocalStateDB.synchronizerStateDB for the given batchNum. If fromSynchronizer is false, get the state from LocalStateDB checkpoints.
 func (l *LocalStateDB) Reset(batchNum uint64, fromSynchronizer bool) error {
+	if batchNum == 0 {
+		l.idx = 0
+		return nil
+	}
 
 	synchronizerCheckpointPath := l.synchronizerStateDB.path + PATHBATCHNUM + strconv.Itoa(int(batchNum))
 	checkpointPath := l.path + PATHBATCHNUM + strconv.Itoa(int(batchNum))

db/statedb/txprocessors.go

@@ -0,0 +1,195 @@
+package statedb
+
+import (
+	"encoding/binary"
+	"math/big"
+
+	"github.com/hermeznetwork/hermez-node/common"
+	"github.com/iden3/go-merkletree/db"
+)
+
+// KEYIDX is used as key in the db to store the current Idx
+var KEYIDX = []byte("idx")
+
+// ProcessPoolL2Tx process the given PoolL2Tx applying the needed updates to
+// the StateDB depending on the transaction Type.
+func (s *StateDB) ProcessPoolL2Tx(tx *common.PoolL2Tx) 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 err
+		}
+	case common.TxTypeExit:
+		// execute exit flow
+	default:
+	}
+	return nil
+}
+
+// ProcessL1Tx process the given L1Tx applying the needed updates to the
+// StateDB depending on the transaction Type.
+func (s *StateDB) ProcessL1Tx(tx *common.L1Tx) 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 err
+		}
+	case common.TxTypeCreateAccountDeposit:
+		// add new account to the MT, update balance of the MT account
+		err := s.applyCreateAccount(tx)
+		if err != nil {
+			return err
+		}
+	case common.TxTypeDeposit:
+		// update balance of the MT account
+		err := s.applyDeposit(tx, false)
+		if err != nil {
+			return err
+		}
+	case common.TxTypeDepositTransfer:
+		// update balance in MT account, update balance & nonce of sender
+		// & receiver
+		err := s.applyDeposit(tx, true)
+		if err != nil {
+			return 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 err
+		}
+		err = s.applyTransfer(tx.Tx())
+		if err != nil {
+			return err
+		}
+	case common.TxTypeExit:
+		// execute exit flow
+	default:
+	}
+
+	return 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
+	}
+
+	// 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
+}
+
+// getIdx returns the stored Idx from the localStateDB, which is the last Idx
+// used for an Account in the localStateDB.
+func (s *StateDB) getIdx() (uint64, error) {
+	idxBytes, err := s.DB().Get(KEYIDX)
+	if err == db.ErrNotFound {
+		return 0, nil
+	}
+	if err != nil {
+		return 0, err
+	}
+	idx := binary.LittleEndian.Uint64(idxBytes[:8])
+	return idx, nil
+}
+
+// setIdx stores Idx in the localStateDB
+func (s *StateDB) setIdx(idx uint64) error {
+	tx, err := s.DB().NewTx()
+	if err != nil {
+		return err
+	}
+	var idxBytes [8]byte
+	binary.LittleEndian.PutUint64(idxBytes[:], idx)
+	tx.Put(KEYIDX, idxBytes[:])
+	if err := tx.Commit(); err != nil {
+		return err
+	}
+	return nil
+}