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package statedb
import (
"errors"
"fmt"
"os"
"os/exec"
"strconv"
"github.com/hermeznetwork/hermez-node/common"
"github.com/iden3/go-merkletree"
"github.com/iden3/go-merkletree/db"
"github.com/iden3/go-merkletree/db/pebble"
)
// TODO(Edu): Document here how StateDB is kept consistent
// ErrStateDBWithoutMT is used when a method that requires a MerkleTree is
// called in a StateDB that does not have a MerkleTree defined
var ErrStateDBWithoutMT = errors.New("Can not call method to use MerkleTree in a StateDB without MerkleTree")
// ErrAccountAlreadyExists is used when CreateAccount is called and the Account
// already exists
var ErrAccountAlreadyExists = errors.New("Can not CreateAccount because Account already exists")
// KeyCurrentBatch is used as key in the db to store the current BatchNum
var KeyCurrentBatch = []byte("currentbatch")
// PathStateDB defines the subpath of the StateDB
const PathStateDB = "/statedb"
// PathBatchNum defines the subpath of the Batch Checkpoint in the subpath of
// the StateDB
const PathBatchNum = "/BatchNum"
// PathCurrent defines the subpath of the current Batch in the subpath of the
// StateDB
const PathCurrent = "/current"
// StateDB represents the StateDB object
type StateDB struct {
path string
currentBatch common.BatchNum
db *pebble.PebbleStorage
mt *merkletree.MerkleTree
// idx holds the current Idx that the BatchBuilder is using
idx common.Idx
zki *common.ZKInputs
i int // i is the current transaction index in the ZKInputs generation (zki)
}
// NewStateDB creates a new StateDB, allowing to use an in-memory or in-disk
// storage
func NewStateDB(path string, withMT bool, nLevels int) (*StateDB, error) {
var sto *pebble.PebbleStorage
var err error
sto, err = pebble.NewPebbleStorage(path+PathStateDB+PathCurrent, false)
if err != nil {
return nil, err
}
var mt *merkletree.MerkleTree = nil
if withMT {
mt, err = merkletree.NewMerkleTree(sto, nLevels)
if err != nil {
return nil, err
}
}
sdb := &StateDB{
path: path + PathStateDB,
db: sto,
mt: mt,
}
// load currentBatch
sdb.currentBatch, err = sdb.GetCurrentBatch()
if err != nil {
return nil, err
}
// make reset (get checkpoint) at currentBatch
err = sdb.Reset(sdb.currentBatch)
if err != nil {
return nil, err
}
return sdb, nil
}
// DB returns the *pebble.PebbleStorage from the StateDB
func (s *StateDB) DB() *pebble.PebbleStorage {
return s.db
}
// GetCurrentBatch returns the current BatchNum stored in the StateDB
func (s *StateDB) GetCurrentBatch() (common.BatchNum, error) {
cbBytes, err := s.db.Get(KeyCurrentBatch)
if err == db.ErrNotFound {
return 0, nil
}
if err != nil {
return 0, err
}
return common.BatchNumFromBytes(cbBytes)
}
// setCurrentBatch stores the current BatchNum in the StateDB
func (s *StateDB) setCurrentBatch() error {
tx, err := s.db.NewTx()
if err != nil {
return err
}
err = tx.Put(KeyCurrentBatch, s.currentBatch.Bytes())
if err != nil {
return err
}
if err := tx.Commit(); err != nil {
return err
}
return nil
}
// MakeCheckpoint does a checkpoint at the given batchNum in the defined path. Internally this advances & stores the current BatchNum, and then stores a Checkpoint of the current state of the StateDB.
func (s *StateDB) MakeCheckpoint() error {
// advance currentBatch
s.currentBatch++
checkpointPath := s.path + PathBatchNum + strconv.Itoa(int(s.currentBatch))
err := s.setCurrentBatch()
if err != nil {
return err
}
// if checkpoint BatchNum already exist in disk, delete it
if _, err := os.Stat(checkpointPath); !os.IsNotExist(err) {
err := os.RemoveAll(checkpointPath)
if err != nil {
return err
}
}
// execute Checkpoint
err = s.db.Pebble().Checkpoint(checkpointPath)
if err != nil {
return err
}
return nil
}
// DeleteCheckpoint removes if exist the checkpoint of the given batchNum
func (s *StateDB) DeleteCheckpoint(batchNum common.BatchNum) error {
checkpointPath := s.path + PathBatchNum + strconv.Itoa(int(batchNum))
if _, err := os.Stat(checkpointPath); os.IsNotExist(err) {
return fmt.Errorf("Checkpoint with batchNum %d does not exist in DB", batchNum)
}
return os.RemoveAll(checkpointPath)
}
// Reset resets the StateDB to the checkpoint at the given batchNum. Reset
// does not delete the checkpoints between old current and the new current,
// those checkpoints will remain in the storage, and eventually will be
// deleted when MakeCheckpoint overwrites them.
func (s *StateDB) Reset(batchNum common.BatchNum) error {
checkpointPath := s.path + PathBatchNum + strconv.Itoa(int(batchNum))
currentPath := s.path + PathCurrent
// remove 'current'
err := os.RemoveAll(currentPath)
if err != nil {
return err
}
if batchNum == 0 {
// if batchNum == 0, open the new fresh 'current'
sto, err := pebble.NewPebbleStorage(currentPath, false)
if err != nil {
return err
}
s.db = sto
s.idx = 0
s.currentBatch = batchNum
return nil
}
// copy 'BatchNumX' to 'current'
cmd := exec.Command("cp", "-r", checkpointPath, currentPath) //nolint:gosec
err = cmd.Run()
if err != nil {
return err
}
// open the new 'current'
sto, err := pebble.NewPebbleStorage(currentPath, false)
if err != nil {
return err
}
s.db = sto
// get currentBatch num
s.currentBatch, err = s.GetCurrentBatch()
if err != nil {
return err
}
// idx is obtained from the statedb reset
s.idx, err = s.getIdx()
if err != nil {
return err
}
if s.mt != nil {
// open the MT for the current s.db
mt, err := merkletree.NewMerkleTree(s.db, s.mt.MaxLevels())
if err != nil {
return err
}
s.mt = mt
}
return nil
}
// GetAccount returns the account for the given Idx
func (s *StateDB) GetAccount(idx common.Idx) (*common.Account, error) {
return getAccountInTreeDB(s.db, idx)
}
// getAccountInTreeDB is abstracted from StateDB to be used from StateDB and
// from ExitTree. GetAccount returns the account for the given Idx
func getAccountInTreeDB(sto db.Storage, idx common.Idx) (*common.Account, error) {
vBytes, err := sto.Get(idx.Bytes())
if err != nil {
return nil, err
}
accBytes, err := sto.Get(vBytes)
if err != nil {
return nil, err
}
var b [32 * common.NLeafElems]byte
copy(b[:], accBytes)
return common.AccountFromBytes(b)
}
// CreateAccount creates a new Account in the StateDB for the given Idx. If
// StateDB.mt==nil, MerkleTree is not affected, otherwise updates the
// MerkleTree, returning a CircomProcessorProof.
func (s *StateDB) CreateAccount(idx common.Idx, account *common.Account) (*merkletree.CircomProcessorProof, error) {
return createAccountInTreeDB(s.db, s.mt, idx, account)
}
// createAccountInTreeDB is abstracted from StateDB to be used from StateDB and
// from ExitTree. Creates a new Account in the StateDB for the given Idx. If
// StateDB.mt==nil, MerkleTree is not affected, otherwise updates the
// MerkleTree, returning a CircomProcessorProof.
func createAccountInTreeDB(sto db.Storage, mt *merkletree.MerkleTree, idx common.Idx, account *common.Account) (*merkletree.CircomProcessorProof, error) {
// store at the DB the key: v, and value: leaf.Bytes()
v, err := account.HashValue()
if err != nil {
return nil, err
}
accountBytes, err := account.Bytes()
if err != nil {
return nil, err
}
// store the Leaf value
tx, err := sto.NewTx()
if err != nil {
return nil, err
}
_, err = tx.Get(idx.Bytes())
if err != db.ErrNotFound {
return nil, ErrAccountAlreadyExists
}
err = tx.Put(v.Bytes(), accountBytes[:])
if err != nil {
return nil, err
}
err = tx.Put(idx.Bytes(), v.Bytes())
if err != nil {
return nil, err
}
if err := tx.Commit(); err != nil {
return nil, err
}
if mt != nil {
return mt.AddAndGetCircomProof(idx.BigInt(), v)
}
return nil, nil
}
// UpdateAccount updates the Account in the StateDB for the given Idx. If
// StateDB.mt==nil, MerkleTree is not affected, otherwise updates the
// MerkleTree, returning a CircomProcessorProof.
func (s *StateDB) UpdateAccount(idx common.Idx, account *common.Account) (*merkletree.CircomProcessorProof, error) {
return updateAccountInTreeDB(s.db, s.mt, idx, account)
}
// updateAccountInTreeDB is abstracted from StateDB to be used from StateDB and
// from ExitTree. Updates the Account in the StateDB for the given Idx. If
// StateDB.mt==nil, MerkleTree is not affected, otherwise updates the
// MerkleTree, returning a CircomProcessorProof.
func updateAccountInTreeDB(sto db.Storage, mt *merkletree.MerkleTree, idx common.Idx, account *common.Account) (*merkletree.CircomProcessorProof, error) {
// store at the DB the key: v, and value: account.Bytes()
v, err := account.HashValue()
if err != nil {
return nil, err
}
accountBytes, err := account.Bytes()
if err != nil {
return nil, err
}
tx, err := sto.NewTx()
if err != nil {
return nil, err
}
err = tx.Put(v.Bytes(), accountBytes[:])
if err != nil {
return nil, err
}
err = tx.Put(idx.Bytes(), v.Bytes())
if err != nil {
return nil, err
}
if err := tx.Commit(); err != nil {
return nil, err
}
if mt != nil {
return mt.Update(idx.BigInt(), v)
}
return nil, nil
}
// MTGetProof returns the CircomVerifierProof for a given Idx
func (s *StateDB) MTGetProof(idx common.Idx) (*merkletree.CircomVerifierProof, error) {
if s.mt == nil {
return nil, ErrStateDBWithoutMT
}
return s.mt.GenerateCircomVerifierProof(idx.BigInt(), s.mt.Root())
}
// LocalStateDB represents the local StateDB which allows to make copies from
// the synchronizer StateDB, and is used by the tx-selector and the
// batch-builder. LocalStateDB is an in-memory storage.
type LocalStateDB struct {
*StateDB
synchronizerStateDB *StateDB
}
// NewLocalStateDB returns a new LocalStateDB connected to the given
// synchronizerDB
func NewLocalStateDB(path string, synchronizerDB *StateDB, withMT bool, nLevels int) (*LocalStateDB, error) {
s, err := NewStateDB(path, withMT, nLevels)
if err != nil {
return nil, err
}
return &LocalStateDB{
s,
synchronizerDB,
}, nil
}
// 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 common.BatchNum, 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))
currentPath := l.path + PathCurrent
if fromSynchronizer {
// use checkpoint from SynchronizerStateDB
if _, err := os.Stat(synchronizerCheckpointPath); os.IsNotExist(err) {
// if synchronizerStateDB does not have checkpoint at batchNum, return err
return fmt.Errorf("Checkpoint not exist in Synchronizer")
}
// remove 'current'
err := os.RemoveAll(currentPath)
if err != nil {
return err
}
// copy synchronizer'BatchNumX' to 'current'
cmd := exec.Command("cp", "-r", synchronizerCheckpointPath, currentPath) //nolint:gosec
err = cmd.Run()
if err != nil {
return err
}
// copy synchronizer-'BatchNumX' to 'BatchNumX'
cmd = exec.Command("cp", "-r", synchronizerCheckpointPath, checkpointPath) //nolint:gosec
err = cmd.Run()
if err != nil {
return err
}
// open the new 'current'
sto, err := pebble.NewPebbleStorage(currentPath, false)
if err != nil {
return err
}
l.db = sto
// get currentBatch num
l.currentBatch, err = l.GetCurrentBatch()
if err != nil {
return err
}
// open the MT for the current s.db
mt, err := merkletree.NewMerkleTree(l.db, l.mt.MaxLevels())
if err != nil {
return err
}
l.mt = mt
return nil
}
// use checkpoint from LocalStateDB
return l.StateDB.Reset(batchNum)
}