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package statedb
import (
"errors"
"fmt"
"math/big"
"os"
"strconv"
"github.com/hermeznetwork/hermez-node/common"
"github.com/hermeznetwork/hermez-node/log"
"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
var (
// ErrStateDBWithoutMT is used when a method that requires a MerkleTree
// is called in a StateDB that does not have a MerkleTree defined
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
ErrAccountAlreadyExists = errors.New("Can not CreateAccount because Account already exists")
// ErrToIdxNotFound is used when trying to get the ToIdx from ToEthAddr
// or ToEthAddr&ToBJJ
ErrToIdxNotFound = errors.New("ToIdx can not be found")
// ErrGetIdxNoCase is used when trying to get the Idx from EthAddr &
// BJJ with not compatible combination
ErrGetIdxNoCase = errors.New("Can not get Idx due unexpected combination of ethereum Address & BabyJubJub PublicKey")
// KeyCurrentBatch is used as key in the db to store the current BatchNum
KeyCurrentBatch = []byte("k:currentbatch")
// PrefixKeyIdx is the key prefix for idx in the db
PrefixKeyIdx = []byte("i:")
// PrefixKeyAccHash is the key prefix for account hash in the db
PrefixKeyAccHash = []byte("h:")
// PrefixKeyMT is the key prefix for merkle tree in the db
PrefixKeyMT = []byte("m:")
// PrefixKeyAddr is the key prefix for address in the db
PrefixKeyAddr = []byte("a:")
// PrefixKeyAddrBJJ is the key prefix for address-babyjubjub in the db
PrefixKeyAddrBJJ = []byte("ab:")
)
const (
// PathBatchNum defines the subpath of the Batch Checkpoint in the
// subpath of the StateDB
PathBatchNum = "/BatchNum"
// PathCurrent defines the subpath of the current Batch in the subpath
// of the StateDB
PathCurrent = "/current"
// TypeSynchronizer defines a StateDB used by the Synchronizer, that
// generates the ExitTree when processing the txs
TypeSynchronizer = "synchronizer"
// TypeTxSelector defines a StateDB used by the TxSelector, without
// computing ExitTree neither the ZKInputs
TypeTxSelector = "txselector"
// TypeBatchBuilder defines a StateDB used by the BatchBuilder, that
// generates the ExitTree and the ZKInput when processing the txs
TypeBatchBuilder = "batchbuilder"
)
// TypeStateDB determines the type of StateDB
type TypeStateDB string
// StateDB represents the StateDB object
type StateDB struct {
path string
currentBatch common.BatchNum
db *pebble.PebbleStorage
mt *merkletree.MerkleTree
typ TypeStateDB
// 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, typ TypeStateDB, nLevels int) (*StateDB, error) {
var sto *pebble.PebbleStorage
var err error
sto, err = pebble.NewPebbleStorage(path+PathCurrent, false)
if err != nil {
return nil, err
}
var mt *merkletree.MerkleTree = nil
if typ == TypeSynchronizer || typ == TypeBatchBuilder {
mt, err = merkletree.NewMerkleTree(sto.WithPrefix(PrefixKeyMT), nLevels)
if err != nil {
return nil, err
}
}
if typ == TypeTxSelector && nLevels != 0 {
return nil, fmt.Errorf("invalid StateDB parameters: StateDB type==TypeStateDB can not have nLevels!=0")
}
sdb := &StateDB{
path: path,
db: sto,
mt: mt,
typ: typ,
}
// load currentBatch
sdb.currentBatch, err = sdb.GetCurrentBatch()
if err != nil {
return nil, err
}
// make reset (get checkpoint) at currentBatch
err = sdb.reset(sdb.currentBatch, false)
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++
log.Debugw("Making StateDB checkpoint", "batch", s.currentBatch, "type", s.typ)
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
}
} else if err != nil && !os.IsNotExist(err) {
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)
}
func pebbleMakeCheckpoint(source, dest string) error {
// Remove dest folder (if it exists) before doing the checkpoint
if _, err := os.Stat(dest); !os.IsNotExist(err) {
err := os.RemoveAll(dest)
if err != nil {
return err
}
} else if err != nil && !os.IsNotExist(err) {
return err
}
sto, err := pebble.NewPebbleStorage(source, false)
if err != nil {
return err
}
defer func() {
errClose := sto.Pebble().Close()
if errClose != nil {
log.Errorw("Pebble.Close", "err", errClose)
}
}()
// execute Checkpoint
err = sto.Pebble().Checkpoint(dest)
if err != nil {
return err
}
return nil
}
// 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 {
return s.reset(batchNum, true)
}
// 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. `closeCurrent` will close the
// currently opened db before doing the reset.
func (s *StateDB) reset(batchNum common.BatchNum, closeCurrent bool) error {
checkpointPath := s.path + PathBatchNum + strconv.Itoa(int(batchNum))
currentPath := s.path + PathCurrent
if closeCurrent {
if err := s.db.Pebble().Close(); err != nil {
return err
}
}
// 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 = 255
s.currentBatch = batchNum
return nil
}
// copy 'BatchNumX' to 'current'
err = pebbleMakeCheckpoint(checkpointPath, currentPath)
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.WithPrefix(PrefixKeyMT), 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)
}
// GetAccounts returns all the accounts in the db. Use for debugging pruposes
// only.
func (s *StateDB) GetAccounts() ([]common.Account, error) {
idxDB := s.db.WithPrefix(PrefixKeyIdx)
idxs := []common.Idx{}
// NOTE: Current implementation of Iterate in the pebble interface is
// not efficient, as it iterates over all keys. Improve it following
// this example: https://github.com/cockroachdb/pebble/pull/923/files
if err := idxDB.Iterate(func(k []byte, v []byte) (bool, error) {
idx, err := common.IdxFromBytes(k)
if err != nil {
return false, err
}
idxs = append(idxs, idx)
return true, nil
}); err != nil {
return nil, err
}
accs := []common.Account{}
for i := range idxs {
acc, err := s.GetAccount(idxs[i])
if err != nil {
return nil, err
}
accs = append(accs, *acc)
}
return accs, nil
}
// 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) {
idxBytes, err := idx.Bytes()
if err != nil {
return nil, err
}
vBytes, err := sto.Get(append(PrefixKeyIdx, idxBytes[:]...))
if err != nil {
return nil, err
}
accBytes, err := sto.Get(append(PrefixKeyAccHash, vBytes...))
if err != nil {
return nil, err
}
var b [32 * common.NLeafElems]byte
copy(b[:], accBytes)
account, err := common.AccountFromBytes(b)
if err != nil {
return nil, err
}
account.Idx = idx
return account, nil
}
// 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) {
cpp, err := createAccountInTreeDB(s.db, s.mt, idx, account)
if err != nil {
return cpp, err
}
// store idx by EthAddr & BJJ
err = s.setIdxByEthAddrBJJ(idx, account.EthAddr, account.PublicKey, account.TokenID)
return cpp, err
}
// 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
}
idxBytes, err := idx.Bytes()
if err != nil {
return nil, err
}
_, err = tx.Get(append(PrefixKeyIdx, idxBytes[:]...))
if err != db.ErrNotFound {
return nil, ErrAccountAlreadyExists
}
err = tx.Put(append(PrefixKeyAccHash, v.Bytes()...), accountBytes[:])
if err != nil {
return nil, err
}
err = tx.Put(append(PrefixKeyIdx, idxBytes[:]...), 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(append(PrefixKeyAccHash, v.Bytes()...), accountBytes[:])
if err != nil {
return nil, err
}
idxBytes, err := idx.Bytes()
if err != nil {
return nil, err
}
err = tx.Put(append(PrefixKeyIdx, idxBytes[:]...), 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())
}
// MTGetRoot returns the current root of the underlying Merkle Tree
func (s *StateDB) MTGetRoot() *big.Int {
return s.mt.Root().BigInt()
}
// 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, typ TypeStateDB, nLevels int) (*LocalStateDB, error) {
s, err := NewStateDB(path, typ, 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")
}
if err := l.db.Pebble().Close(); err != nil {
return err
}
// remove 'current'
err := os.RemoveAll(currentPath)
if err != nil {
return err
}
// copy synchronizer'BatchNumX' to 'current'
err = pebbleMakeCheckpoint(synchronizerCheckpointPath, currentPath)
if err != nil {
return err
}
// copy synchronizer'BatchNumX' to 'BatchNumX'
err = pebbleMakeCheckpoint(synchronizerCheckpointPath, checkpointPath)
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.WithPrefix(PrefixKeyMT), l.mt.MaxLevels())
if err != nil {
return err
}
l.mt = mt
return nil
}
// use checkpoint from LocalStateDB
return l.StateDB.reset(batchNum, true)
}