Move old state code to x/evm/types

x/evm/types/dump.go

@@ -0,0 +1,12 @@
+package types
+
+import (
+	ethstate "github.com/ethereum/go-ethereum/core/state"
+)
+
+// RawDump returns a raw state dump.
+//
+// TODO: Implement if we need it, especially for the RPC API.
+func (csdb *CommitStateDB) RawDump() ethstate.Dump {
+	return ethstate.Dump{}
+}

x/evm/types/journal.go

@@ -0,0 +1,227 @@
+package types
+
+import (
+	sdk "github.com/cosmos/cosmos-sdk/types"
+
+	ethcmn "github.com/ethereum/go-ethereum/common"
+)
+
+var ripemd = ethcmn.HexToAddress("0000000000000000000000000000000000000003")
+
+// journalEntry is a modification entry in the state change journal that can be
+// reverted on demand.
+type journalEntry interface {
+	// revert undoes the changes introduced by this journal entry.
+	revert(*CommitStateDB)
+
+	// dirtied returns the Ethereum address modified by this journal entry.
+	dirtied() *ethcmn.Address
+}
+
+// journal contains the list of state modifications applied since the last state
+// commit. These are tracked to be able to be reverted in case of an execution
+// exception or revertal request.
+type journal struct {
+	entries []journalEntry         // Current changes tracked by the journal
+	dirties map[ethcmn.Address]int // Dirty accounts and the number of changes
+}
+
+// newJournal create a new initialized journal.
+func newJournal() *journal {
+	return &journal{
+		dirties: make(map[ethcmn.Address]int),
+	}
+}
+
+// append inserts a new modification entry to the end of the change journal.
+func (j *journal) append(entry journalEntry) {
+	j.entries = append(j.entries, entry)
+	if addr := entry.dirtied(); addr != nil {
+		j.dirties[*addr]++
+	}
+}
+
+// revert undoes a batch of journalled modifications along with any reverted
+// dirty handling too.
+func (j *journal) revert(statedb *CommitStateDB, snapshot int) {
+	for i := len(j.entries) - 1; i >= snapshot; i-- {
+		// Undo the changes made by the operation
+		j.entries[i].revert(statedb)
+
+		// Drop any dirty tracking induced by the change
+		if addr := j.entries[i].dirtied(); addr != nil {
+			if j.dirties[*addr]--; j.dirties[*addr] == 0 {
+				delete(j.dirties, *addr)
+			}
+		}
+	}
+	j.entries = j.entries[:snapshot]
+}
+
+// dirty explicitly sets an address to dirty, even if the change entries would
+// otherwise suggest it as clean. This method is an ugly hack to handle the RIPEMD
+// precompile consensus exception.
+func (j *journal) dirty(addr ethcmn.Address) {
+	j.dirties[addr]++
+}
+
+// length returns the current number of entries in the journal.
+func (j *journal) length() int {
+	return len(j.entries)
+}
+
+type (
+	// Changes to the account trie.
+	createObjectChange struct {
+		account *ethcmn.Address
+	}
+
+	resetObjectChange struct {
+		prev *stateObject
+	}
+
+	suicideChange struct {
+		account     *ethcmn.Address
+		prev        bool // whether account had already suicided
+		prevBalance sdk.Int
+	}
+
+	// Changes to individual accounts.
+	balanceChange struct {
+		account *ethcmn.Address
+		prev    sdk.Int
+	}
+
+	nonceChange struct {
+		account *ethcmn.Address
+		prev    int64
+	}
+
+	storageChange struct {
+		account        *ethcmn.Address
+		key, prevValue ethcmn.Hash
+	}
+
+	codeChange struct {
+		account            *ethcmn.Address
+		prevCode, prevHash []byte
+	}
+
+	// Changes to other state values.
+	refundChange struct {
+		prev uint64
+	}
+
+	addLogChange struct {
+		txhash ethcmn.Hash
+	}
+
+	addPreimageChange struct {
+		hash ethcmn.Hash
+	}
+
+	touchChange struct {
+		account   *ethcmn.Address
+		prev      bool
+		prevDirty bool
+	}
+)
+
+func (ch createObjectChange) revert(s *CommitStateDB) {
+	delete(s.stateObjects, *ch.account)
+	delete(s.stateObjectsDirty, *ch.account)
+}
+
+func (ch createObjectChange) dirtied() *ethcmn.Address {
+	return ch.account
+}
+
+func (ch resetObjectChange) revert(s *CommitStateDB) {
+	s.setStateObject(ch.prev)
+}
+
+func (ch resetObjectChange) dirtied() *ethcmn.Address {
+	return nil
+}
+
+func (ch suicideChange) revert(s *CommitStateDB) {
+	so := s.getStateObject(*ch.account)
+	if so != nil {
+		so.suicided = ch.prev
+		so.setBalance(ch.prevBalance)
+	}
+}
+
+func (ch suicideChange) dirtied() *ethcmn.Address {
+	return ch.account
+}
+
+func (ch touchChange) revert(s *CommitStateDB) {
+}
+
+func (ch touchChange) dirtied() *ethcmn.Address {
+	return ch.account
+}
+
+func (ch balanceChange) revert(s *CommitStateDB) {
+	s.getStateObject(*ch.account).setBalance(ch.prev)
+}
+
+func (ch balanceChange) dirtied() *ethcmn.Address {
+	return ch.account
+}
+
+func (ch nonceChange) revert(s *CommitStateDB) {
+	s.getStateObject(*ch.account).setNonce(ch.prev)
+}
+
+func (ch nonceChange) dirtied() *ethcmn.Address {
+	return ch.account
+}
+
+func (ch codeChange) revert(s *CommitStateDB) {
+	s.getStateObject(*ch.account).setCode(ethcmn.BytesToHash(ch.prevHash), ch.prevCode)
+}
+
+func (ch codeChange) dirtied() *ethcmn.Address {
+	return ch.account
+}
+
+func (ch storageChange) revert(s *CommitStateDB) {
+	s.getStateObject(*ch.account).setState(ch.key, ch.prevValue)
+}
+
+func (ch storageChange) dirtied() *ethcmn.Address {
+	return ch.account
+}
+
+func (ch refundChange) revert(s *CommitStateDB) {
+	s.refund = ch.prev
+}
+
+func (ch refundChange) dirtied() *ethcmn.Address {
+	return nil
+}
+
+func (ch addLogChange) revert(s *CommitStateDB) {
+	logs := s.logs[ch.txhash]
+	if len(logs) == 1 {
+		delete(s.logs, ch.txhash)
+	} else {
+		s.logs[ch.txhash] = logs[:len(logs)-1]
+	}
+
+	s.logSize--
+}
+
+func (ch addLogChange) dirtied() *ethcmn.Address {
+	return nil
+}
+
+func (ch addPreimageChange) revert(s *CommitStateDB) {
+	delete(s.preimages, ch.hash)
+}
+
+func (ch addPreimageChange) dirtied() *ethcmn.Address {
+	return nil
+}

x/evm/types/state_object.go

@@ -0,0 +1,366 @@
+package types
+
+import (
+	"bytes"
+	"fmt"
+	"math/big"
+
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	auth "github.com/cosmos/cosmos-sdk/x/auth"
+
+	"github.com/cosmos/ethermint/types"
+	ethcmn "github.com/ethereum/go-ethereum/common"
+	ethstate "github.com/ethereum/go-ethereum/core/state"
+	ethcrypto "github.com/ethereum/go-ethereum/crypto"
+)
+
+var (
+	_ ethstate.StateObject = (*stateObject)(nil)
+
+	emptyCodeHash = ethcrypto.Keccak256(nil)
+)
+
+type (
+	// stateObject represents an Ethereum account which is being modified.
+	//
+	// The usage pattern is as follows:
+	// First you need to obtain a state object.
+	// Account values can be accessed and modified through the object.
+	// Finally, call CommitTrie to write the modified storage trie into a database.
+	stateObject struct {
+		address ethcmn.Address
+		stateDB *CommitStateDB
+		account *types.Account
+
+		// DB error.
+		// State objects are used by the consensus core and VM which are
+		// unable to deal with database-level errors. Any error that occurs
+		// during a database read is memoized here and will eventually be returned
+		// by StateDB.Commit.
+		dbErr error
+
+		code types.Code // contract bytecode, which gets set when code is loaded
+
+		originStorage types.Storage // Storage cache of original entries to dedup rewrites
+		dirtyStorage  types.Storage // Storage entries that need to be flushed to disk
+
+		// cache flags
+		//
+		// When an object is marked suicided it will be delete from the trie during
+		// the "update" phase of the state transition.
+		dirtyCode bool // true if the code was updated
+		suicided  bool
+		deleted   bool
+	}
+)
+
+func newObject(db *CommitStateDB, accProto auth.Account) *stateObject {
+	acc, ok := accProto.(*types.Account)
+	if !ok {
+		panic(fmt.Sprintf("invalid account type for state object: %T", acc))
+	}
+
+	if acc.CodeHash == nil {
+		acc.CodeHash = emptyCodeHash
+	}
+
+	return &stateObject{
+		stateDB:       db,
+		account:       acc,
+		address:       ethcmn.BytesToAddress(acc.Address.Bytes()),
+		originStorage: make(types.Storage),
+		dirtyStorage:  make(types.Storage),
+	}
+}
+
+// ----------------------------------------------------------------------------
+// Setters
+// ----------------------------------------------------------------------------
+
+// SetState updates a value in account storage. Note, the key will be prefixed
+// with the address of the state object.
+func (so *stateObject) SetState(db ethstate.Database, key, value ethcmn.Hash) {
+	// if the new value is the same as old, don't set
+	prev := so.GetState(db, key)
+	if prev == value {
+		return
+	}
+
+	prefixKey := so.GetStorageByAddressKey(key.Bytes())
+
+	// since the new value is different, update and journal the change
+	so.stateDB.journal.append(storageChange{
+		account:   &so.address,
+		key:       prefixKey,
+		prevValue: prev,
+	})
+
+	so.setState(prefixKey, value)
+}
+
+func (so *stateObject) setState(key, value ethcmn.Hash) {
+	so.dirtyStorage[key] = value
+}
+
+// SetCode sets the state object's code.
+func (so *stateObject) SetCode(codeHash ethcmn.Hash, code []byte) {
+	prevCode := so.Code(nil)
+
+	so.stateDB.journal.append(codeChange{
+		account:  &so.address,
+		prevHash: so.CodeHash(),
+		prevCode: prevCode,
+	})
+
+	so.setCode(codeHash, code)
+}
+
+func (so *stateObject) setCode(codeHash ethcmn.Hash, code []byte) {
+	so.code = code
+	so.account.CodeHash = codeHash.Bytes()
+	so.dirtyCode = true
+}
+
+// AddBalance adds an amount to a state object's balance. It is used to add
+// funds to the destination account of a transfer.
+func (so *stateObject) AddBalance(amount *big.Int) {
+	amt := sdk.NewIntFromBigInt(amount)
+
+	// EIP158: We must check emptiness for the objects such that the account
+	// clearing (0,0,0 objects) can take effect.
+	if amt.Sign() == 0 {
+		if so.empty() {
+			so.touch()
+		}
+
+		return
+	}
+
+	newBalance := so.account.Balance().Add(amt)
+	so.SetBalance(newBalance.BigInt())
+}
+
+// SubBalance removes an amount from the stateObject's balance. It is used to
+// remove funds from the origin account of a transfer.
+func (so *stateObject) SubBalance(amount *big.Int) {
+	amt := sdk.NewIntFromBigInt(amount)
+
+	if amt.Sign() == 0 {
+		return
+	}
+
+	newBalance := so.account.Balance().Sub(amt)
+	so.SetBalance(newBalance.BigInt())
+}
+
+// SetBalance sets the state object's balance.
+func (so *stateObject) SetBalance(amount *big.Int) {
+	amt := sdk.NewIntFromBigInt(amount)
+
+	so.stateDB.journal.append(balanceChange{
+		account: &so.address,
+		prev:    so.account.Balance(),
+	})
+
+	so.setBalance(amt)
+}
+
+func (so *stateObject) setBalance(amount sdk.Int) {
+	so.account.SetBalance(amount)
+}
+
+// SetNonce sets the state object's nonce (sequence number).
+func (so *stateObject) SetNonce(nonce uint64) {
+	so.stateDB.journal.append(nonceChange{
+		account: &so.address,
+		prev:    so.account.Sequence,
+	})
+
+	so.setNonce(int64(nonce))
+}
+
+func (so *stateObject) setNonce(nonce int64) {
+	so.account.Sequence = nonce
+}
+
+// setError remembers the first non-nil error it is called with.
+func (so *stateObject) setError(err error) {
+	if so.dbErr == nil {
+		so.dbErr = err
+	}
+}
+
+func (so *stateObject) markSuicided() {
+	so.suicided = true
+}
+
+// commitState commits all dirty storage to a KVStore.
+func (so *stateObject) commitState() {
+	ctx := so.stateDB.ctx
+	store := ctx.KVStore(so.stateDB.storageKey)
+
+	for key, value := range so.dirtyStorage {
+		delete(so.dirtyStorage, key)
+
+		// skip no-op changes, persist actual changes
+		if value == so.originStorage[key] {
+			continue
+		}
+
+		so.originStorage[key] = value
+
+		// delete empty values
+		if (value == ethcmn.Hash{}) {
+			store.Delete(key.Bytes())
+			continue
+		}
+
+		store.Set(key.Bytes(), value.Bytes())
+	}
+
+	// TODO: Set the account (storage) root (but we probably don't need this)
+}
+
+// commitCode persists the state object's code to the KVStore.
+func (so *stateObject) commitCode() {
+	ctx := so.stateDB.ctx
+	store := ctx.KVStore(so.stateDB.codeKey)
+	store.Set(so.CodeHash(), so.code)
+}
+
+// ----------------------------------------------------------------------------
+// Getters
+// ----------------------------------------------------------------------------
+
+// Address returns the address of the state object.
+func (so stateObject) Address() ethcmn.Address {
+	return so.address
+}
+
+// Balance returns the state object's current balance.
+func (so *stateObject) Balance() *big.Int {
+	return so.account.Balance().BigInt()
+}
+
+// CodeHash returns the state object's code hash.
+func (so *stateObject) CodeHash() []byte {
+	return so.account.CodeHash
+}
+
+// Nonce returns the state object's current nonce (sequence number).
+func (so *stateObject) Nonce() uint64 {
+	return uint64(so.account.Sequence)
+}
+
+// Code returns the contract code associated with this object, if any.
+func (so *stateObject) Code(_ ethstate.Database) []byte {
+	if so.code != nil {
+		return so.code
+	}
+
+	if bytes.Equal(so.CodeHash(), emptyCodeHash) {
+		return nil
+	}
+
+	ctx := so.stateDB.ctx
+	store := ctx.KVStore(so.stateDB.codeKey)
+	code := store.Get(so.CodeHash())
+
+	if len(code) == 0 {
+		so.setError(fmt.Errorf("failed to get code hash %x for address: %x", so.CodeHash(), so.Address()))
+	}
+
+	so.code = code
+	return code
+}
+
+// GetState retrieves a value from the account storage trie. Note, the key will
+// be prefixed with the address of the state object.
+func (so *stateObject) GetState(db ethstate.Database, key ethcmn.Hash) ethcmn.Hash {
+	prefixKey := so.GetStorageByAddressKey(key.Bytes())
+
+	// if we have a dirty value for this state entry, return it
+	value, dirty := so.dirtyStorage[prefixKey]
+	if dirty {
+		return value
+	}
+
+	// otherwise return the entry's original value
+	return so.GetCommittedState(db, key)
+}
+
+// GetCommittedState retrieves a value from the committed account storage trie.
+// Note, the key will be prefixed with the address of the state object.
+func (so *stateObject) GetCommittedState(_ ethstate.Database, key ethcmn.Hash) ethcmn.Hash {
+	prefixKey := so.GetStorageByAddressKey(key.Bytes())
+
+	// if we have the original value cached, return that
+	value, cached := so.originStorage[prefixKey]
+	if cached {
+		return value
+	}
+
+	// otherwise load the value from the KVStore
+	ctx := so.stateDB.ctx
+	store := ctx.KVStore(so.stateDB.storageKey)
+	rawValue := store.Get(prefixKey.Bytes())
+
+	if len(rawValue) > 0 {
+		value.SetBytes(rawValue)
+	}
+
+	so.originStorage[prefixKey] = value
+	return value
+}
+
+// ----------------------------------------------------------------------------
+// Auxiliary
+// ----------------------------------------------------------------------------
+
+// ReturnGas returns the gas back to the origin. Used by the Virtual machine or
+// Closures. It performs a no-op.
+func (so *stateObject) ReturnGas(gas *big.Int) {}
+
+func (so *stateObject) deepCopy(db *CommitStateDB) *stateObject {
+	newStateObj := newObject(db, so.account)
+
+	newStateObj.code = so.code
+	newStateObj.dirtyStorage = so.dirtyStorage.Copy()
+	newStateObj.originStorage = so.originStorage.Copy()
+	newStateObj.suicided = so.suicided
+	newStateObj.dirtyCode = so.dirtyCode
+	newStateObj.deleted = so.deleted
+
+	return newStateObj
+}
+
+// empty returns whether the account is considered empty.
+func (so *stateObject) empty() bool {
+	return so.account.Sequence == 0 &&
+		so.account.Balance().Sign() == 0 &&
+		bytes.Equal(so.account.CodeHash, emptyCodeHash)
+}
+
+func (so *stateObject) touch() {
+	so.stateDB.journal.append(touchChange{
+		account: &so.address,
+	})
+
+	if so.address == ripemd {
+		// Explicitly put it in the dirty-cache, which is otherwise generated from
+		// flattened journals.
+		so.stateDB.journal.dirty(so.address)
+	}
+}
+
+// GetStorageByAddressKey returns a hash of the composite key for a state
+// object's storage prefixed with it's address.
+func (so stateObject) GetStorageByAddressKey(key []byte) ethcmn.Hash {
+	prefix := so.Address().Bytes()
+	compositeKey := make([]byte, len(prefix)+len(key))
+
+	copy(compositeKey, prefix)
+	copy(compositeKey[len(prefix):], key)
+
+	return ethcrypto.Keccak256Hash(compositeKey)
+}

x/evm/types/statedb.go

@@ -0,0 +1,703 @@
+package types
+
+import (
+	"fmt"
+	"math/big"
+	"sort"
+	"sync"
+
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/cosmos-sdk/x/auth"
+
+	ethcmn "github.com/ethereum/go-ethereum/common"
+	ethstate "github.com/ethereum/go-ethereum/core/state"
+	ethtypes "github.com/ethereum/go-ethereum/core/types"
+	ethcrypto "github.com/ethereum/go-ethereum/crypto"
+)
+
+var (
+	_ ethstate.StateDB = (*CommitStateDB)(nil)
+
+	zeroBalance = sdk.ZeroInt().BigInt()
+)
+
+// CommitStateDB implements the Geth state.StateDB interface. Instead of using
+// a trie and database for querying and persistence, the Keeper uses KVStores
+// and an account mapper is used to facilitate state transitions.
+//
+// TODO: This implementation is subject to change in regards to its statefull
+// manner. In otherwords, how this relates to the keeper in this module.
+type CommitStateDB struct {
+	// TODO: We need to store the context as part of the structure itself opposed
+	// to being passed as a parameter (as it should be) in order to implement the
+	// StateDB interface. Perhaps there is a better way.
+	ctx sdk.Context
+
+	am         auth.AccountMapper
+	storageKey sdk.StoreKey
+	codeKey    sdk.StoreKey
+
+	// maps that hold 'live' objects, which will get modified while processing a
+	// state transition
+	stateObjects      map[ethcmn.Address]*stateObject
+	stateObjectsDirty map[ethcmn.Address]struct{}
+
+	// The refund counter, also used by state transitioning.
+	refund uint64
+
+	thash, bhash ethcmn.Hash
+	txIndex      int
+	logs         map[ethcmn.Hash][]*ethtypes.Log
+	logSize      uint
+
+	// TODO: Determine if we actually need this as we do not need preimages in
+	// the SDK, but it seems to be used elsewhere in Geth.
+	preimages map[ethcmn.Hash][]byte
+
+	// DB error.
+	// State objects are used by the consensus core and VM which are
+	// unable to deal with database-level errors. Any error that occurs
+	// during a database read is memo-ized here and will eventually be returned
+	// by StateDB.Commit.
+	dbErr error
+
+	// Journal of state modifications. This is the backbone of
+	// Snapshot and RevertToSnapshot.
+	journal        *journal
+	validRevisions []ethstate.Revision
+	nextRevisionID int
+
+	// mutex for state deep copying
+	lock sync.Mutex
+}
+
+// NewCommitStateDB returns a reference to a newly initialized CommitStateDB
+// which implements Geth's state.StateDB interface.
+//
+// CONTRACT: Stores used for state must be cache-wrapped as the ordering of the
+// key/value space matters in determining the merkle root.
+func NewCommitStateDB(ctx sdk.Context, am auth.AccountMapper, storageKey, codeKey sdk.StoreKey) (*CommitStateDB, error) {
+	return &CommitStateDB{
+		ctx:               ctx,
+		am:                am,
+		storageKey:        storageKey,
+		codeKey:           codeKey,
+		stateObjects:      make(map[ethcmn.Address]*stateObject),
+		stateObjectsDirty: make(map[ethcmn.Address]struct{}),
+		logs:              make(map[ethcmn.Hash][]*ethtypes.Log),
+		preimages:         make(map[ethcmn.Hash][]byte),
+		journal:           newJournal(),
+	}, nil
+}
+
+// ----------------------------------------------------------------------------
+// Setters
+// ----------------------------------------------------------------------------
+
+// SetBalance sets the balance of an account.
+func (csdb *CommitStateDB) SetBalance(addr ethcmn.Address, amount *big.Int) {
+	so := csdb.GetOrNewStateObject(addr)
+	if so != nil {
+		so.SetBalance(amount)
+	}
+}
+
+// AddBalance adds amount to the account associated with addr.
+func (csdb *CommitStateDB) AddBalance(addr ethcmn.Address, amount *big.Int) {
+	so := csdb.GetOrNewStateObject(addr)
+	if so != nil {
+		so.AddBalance(amount)
+	}
+}
+
+// SubBalance subtracts amount from the account associated with addr.
+func (csdb *CommitStateDB) SubBalance(addr ethcmn.Address, amount *big.Int) {
+	so := csdb.GetOrNewStateObject(addr)
+	if so != nil {
+		so.SubBalance(amount)
+	}
+}
+
+// SetNonce sets the nonce (sequence number) of an account.
+func (csdb *CommitStateDB) SetNonce(addr ethcmn.Address, nonce uint64) {
+	so := csdb.GetOrNewStateObject(addr)
+	if so != nil {
+		so.SetNonce(nonce)
+	}
+}
+
+// SetState sets the storage state with a key, value pair for an account.
+func (csdb *CommitStateDB) SetState(addr ethcmn.Address, key, value ethcmn.Hash) {
+	so := csdb.GetOrNewStateObject(addr)
+	if so != nil {
+		so.SetState(nil, key, value)
+	}
+}
+
+// SetCode sets the code for a given account.
+func (csdb *CommitStateDB) SetCode(addr ethcmn.Address, code []byte) {
+	so := csdb.GetOrNewStateObject(addr)
+	if so != nil {
+		so.SetCode(ethcrypto.Keccak256Hash(code), code)
+	}
+}
+
+// AddLog adds a new log to the state and sets the log metadata from the state.
+func (csdb *CommitStateDB) AddLog(log *ethtypes.Log) {
+	csdb.journal.append(addLogChange{txhash: csdb.thash})
+
+	log.TxHash = csdb.thash
+	log.BlockHash = csdb.bhash
+	log.TxIndex = uint(csdb.txIndex)
+	log.Index = csdb.logSize
+	csdb.logs[csdb.thash] = append(csdb.logs[csdb.thash], log)
+	csdb.logSize++
+}
+
+// AddPreimage records a SHA3 preimage seen by the VM.
+func (csdb *CommitStateDB) AddPreimage(hash ethcmn.Hash, preimage []byte) {
+	if _, ok := csdb.preimages[hash]; !ok {
+		csdb.journal.append(addPreimageChange{hash: hash})
+
+		pi := make([]byte, len(preimage))
+		copy(pi, preimage)
+		csdb.preimages[hash] = pi
+	}
+}
+
+// AddRefund adds gas to the refund counter.
+func (csdb *CommitStateDB) AddRefund(gas uint64) {
+	csdb.journal.append(refundChange{prev: csdb.refund})
+	csdb.refund += gas
+}
+
+// SubRefund removes gas from the refund counter. It will panic if the refund
+// counter goes below zero.
+func (csdb *CommitStateDB) SubRefund(gas uint64) {
+	csdb.journal.append(refundChange{prev: csdb.refund})
+	if gas > csdb.refund {
+		panic("refund counter below zero")
+	}
+
+	csdb.refund -= gas
+}
+
+// ----------------------------------------------------------------------------
+// Getters
+// ----------------------------------------------------------------------------
+
+// GetBalance retrieves the balance from the given address or 0 if object not
+// found.
+func (csdb *CommitStateDB) GetBalance(addr ethcmn.Address) *big.Int {
+	so := csdb.getStateObject(addr)
+	if so != nil {
+		return so.Balance()
+	}
+
+	return zeroBalance
+}
+
+// GetNonce returns the nonce (sequence number) for a given account.
+func (csdb *CommitStateDB) GetNonce(addr ethcmn.Address) uint64 {
+	so := csdb.getStateObject(addr)
+	if so != nil {
+		return so.Nonce()
+	}
+
+	return 0
+}
+
+// GetCode returns the code for a given account.
+func (csdb *CommitStateDB) GetCode(addr ethcmn.Address) []byte {
+	so := csdb.getStateObject(addr)
+	if so != nil {
+		return so.Code(nil)
+	}
+
+	return nil
+}
+
+// GetCodeSize returns the code size for a given account.
+func (csdb *CommitStateDB) GetCodeSize(addr ethcmn.Address) int {
+	so := csdb.getStateObject(addr)
+	if so == nil {
+		return 0
+	}
+
+	if so.code != nil {
+		return len(so.code)
+	}
+
+	// TODO: we may need to cache these lookups directly
+	return len(so.Code(nil))
+}
+
+// GetCodeHash returns the code hash for a given account.
+func (csdb *CommitStateDB) GetCodeHash(addr ethcmn.Address) ethcmn.Hash {
+	so := csdb.getStateObject(addr)
+	if so == nil {
+		return ethcmn.Hash{}
+	}
+
+	return ethcmn.BytesToHash(so.CodeHash())
+}
+
+// GetState retrieves a value from the given account's storage store.
+func (csdb *CommitStateDB) GetState(addr ethcmn.Address, hash ethcmn.Hash) ethcmn.Hash {
+	so := csdb.getStateObject(addr)
+	if so != nil {
+		return so.GetState(nil, hash)
+	}
+
+	return ethcmn.Hash{}
+}
+
+// GetCommittedState retrieves a value from the given account's committed
+// storage.
+func (csdb *CommitStateDB) GetCommittedState(addr ethcmn.Address, hash ethcmn.Hash) ethcmn.Hash {
+	so := csdb.getStateObject(addr)
+	if so != nil {
+		return so.GetCommittedState(nil, hash)
+	}
+
+	return ethcmn.Hash{}
+}
+
+// GetLogs returns the current logs for a given hash in the state.
+func (csdb *CommitStateDB) GetLogs(hash ethcmn.Hash) []*ethtypes.Log {
+	return csdb.logs[hash]
+}
+
+// Logs returns all the current logs in the state.
+func (csdb *CommitStateDB) Logs() []*ethtypes.Log {
+	var logs []*ethtypes.Log
+	for _, lgs := range csdb.logs {
+		logs = append(logs, lgs...)
+	}
+
+	return logs
+}
+
+// GetRefund returns the current value of the refund counter.
+func (csdb *CommitStateDB) GetRefund() uint64 {
+	return csdb.refund
+}
+
+// Preimages returns a list of SHA3 preimages that have been submitted.
+func (csdb *CommitStateDB) Preimages() map[ethcmn.Hash][]byte {
+	return csdb.preimages
+}
+
+// HasSuicided returns if the given account for the specified address has been
+// killed.
+func (csdb *CommitStateDB) HasSuicided(addr ethcmn.Address) bool {
+	so := csdb.getStateObject(addr)
+	if so != nil {
+		return so.suicided
+	}
+
+	return false
+}
+
+// StorageTrie returns nil as the state in Ethermint does not use a direct
+// storage trie.
+func (csdb *CommitStateDB) StorageTrie(addr ethcmn.Address) ethstate.Trie {
+	return nil
+}
+
+// ----------------------------------------------------------------------------
+// Persistance
+// ----------------------------------------------------------------------------
+
+// Commit writes the state to the appropriate KVStores. For each state object
+// in the cache, it will either be removed, or have it's code set and/or it's
+// state (storage) updated. In addition, the state object (account) itself will
+// be written. Finally, the root hash (version) will be returned.
+func (csdb *CommitStateDB) Commit(deleteEmptyObjects bool) (root ethcmn.Hash, err error) {
+	defer csdb.clearJournalAndRefund()
+
+	// remove dirty state object entries based on the journal
+	for addr := range csdb.journal.dirties {
+		csdb.stateObjectsDirty[addr] = struct{}{}
+	}
+
+	// set the state objects
+	for addr, so := range csdb.stateObjects {
+		_, isDirty := csdb.stateObjectsDirty[addr]
+
+		switch {
+		case so.suicided || (isDirty && deleteEmptyObjects && so.empty()):
+			// If the state object has been removed, don't bother syncing it and just
+			// remove it from the store.
+			csdb.deleteStateObject(so)
+
+		case isDirty:
+			// write any contract code associated with the state object
+			if so.code != nil && so.dirtyCode {
+				so.commitCode()
+				so.dirtyCode = false
+			}
+
+			// update the object in the KVStore
+			csdb.updateStateObject(so)
+		}
+
+		delete(csdb.stateObjectsDirty, addr)
+	}
+
+	// NOTE: Ethereum returns the trie merkle root here, but as commitment
+	// actually happens in the BaseApp at EndBlocker, we do not know the root at
+	// this time.
+	return
+}
+
+// Finalize finalizes the state objects (accounts) state by setting their state,
+// removing the csdb destructed objects and clearing the journal as well as the
+// refunds.
+func (csdb *CommitStateDB) Finalize(deleteEmptyObjects bool) {
+	for addr := range csdb.journal.dirties {
+		so, exist := csdb.stateObjects[addr]
+		if !exist {
+			// ripeMD is 'touched' at block 1714175, in tx:
+			// 0x1237f737031e40bcde4a8b7e717b2d15e3ecadfe49bb1bbc71ee9deb09c6fcf2
+			//
+			// That tx goes out of gas, and although the notion of 'touched' does not
+			// exist there, the touch-event will still be recorded in the journal.
+			// Since ripeMD is a special snowflake, it will persist in the journal even
+			// though the journal is reverted. In this special circumstance, it may
+			// exist in journal.dirties but not in stateObjects. Thus, we can safely
+			// ignore it here.
+			continue
+		}
+
+		if so.suicided || (deleteEmptyObjects && so.empty()) {
+			csdb.deleteStateObject(so)
+		} else {
+			// Set all the dirty state storage items for the state object in the
+			// KVStore and finally set the account in the account mapper.
+			so.commitState()
+			csdb.updateStateObject(so)
+		}
+
+		csdb.stateObjectsDirty[addr] = struct{}{}
+	}
+
+	// invalidate journal because reverting across transactions is not allowed
+	csdb.clearJournalAndRefund()
+}
+
+// IntermediateRoot returns the current root hash of the state. It is called in
+// between transactions to get the root hash that goes into transaction
+// receipts.
+//
+// NOTE: The SDK has not concept or method of getting any intermediate merkle
+// root as commitment of the merkle-ized tree doesn't happen until the
+// BaseApps' EndBlocker.
+func (csdb *CommitStateDB) IntermediateRoot(deleteEmptyObjects bool) ethcmn.Hash {
+	csdb.Finalize(deleteEmptyObjects)
+
+	return ethcmn.Hash{}
+}
+
+// updateStateObject writes the given state object to the store.
+func (csdb *CommitStateDB) updateStateObject(so *stateObject) {
+	csdb.am.SetAccount(csdb.ctx, so.account)
+}
+
+// deleteStateObject removes the given state object from the state store.
+func (csdb *CommitStateDB) deleteStateObject(so *stateObject) {
+	so.deleted = true
+	csdb.am.RemoveAccount(csdb.ctx, so.account)
+}
+
+// ----------------------------------------------------------------------------
+// Snapshotting
+// ----------------------------------------------------------------------------
+
+// Snapshot returns an identifier for the current revision of the state.
+func (csdb *CommitStateDB) Snapshot() int {
+	id := csdb.nextRevisionID
+	csdb.nextRevisionID++
+
+	csdb.validRevisions = append(
+		csdb.validRevisions,
+		ethstate.Revision{
+			ID:           id,
+			JournalIndex: csdb.journal.length(),
+		},
+	)
+
+	return id
+}
+
+// RevertToSnapshot reverts all state changes made since the given revision.
+func (csdb *CommitStateDB) RevertToSnapshot(revID int) {
+	// find the snapshot in the stack of valid snapshots
+	idx := sort.Search(len(csdb.validRevisions), func(i int) bool {
+		return csdb.validRevisions[i].ID >= revID
+	})
+
+	if idx == len(csdb.validRevisions) || csdb.validRevisions[idx].ID != revID {
+		panic(fmt.Errorf("revision ID %v cannot be reverted", revID))
+	}
+
+	snapshot := csdb.validRevisions[idx].JournalIndex
+
+	// replay the journal to undo changes and remove invalidated snapshots
+	csdb.journal.revert(csdb, snapshot)
+	csdb.validRevisions = csdb.validRevisions[:idx]
+}
+
+// ----------------------------------------------------------------------------
+// Auxiliary
+// ----------------------------------------------------------------------------
+
+// Database retrieves the low level database supporting the lower level trie
+// ops. It is not used in Ethermint, so it returns nil.
+func (csdb *CommitStateDB) Database() ethstate.Database {
+	return nil
+}
+
+// Empty returns whether the state object is either non-existent or empty
+// according to the EIP161 specification (balance = nonce = code = 0).
+func (csdb *CommitStateDB) Empty(addr ethcmn.Address) bool {
+	so := csdb.getStateObject(addr)
+	return so == nil || so.empty()
+}
+
+// Exist reports whether the given account address exists in the state. Notably,
+// this also returns true for suicided accounts.
+func (csdb *CommitStateDB) Exist(addr ethcmn.Address) bool {
+	return csdb.getStateObject(addr) != nil
+}
+
+// Error returns the first non-nil error the StateDB encountered.
+func (csdb *CommitStateDB) Error() error {
+	return csdb.dbErr
+}
+
+// Suicide marks the given account as suicided and clears the account balance.
+//
+// The account's state object is still available until the state is committed,
+// getStateObject will return a non-nil account after Suicide.
+func (csdb *CommitStateDB) Suicide(addr ethcmn.Address) bool {
+	so := csdb.getStateObject(addr)
+	if so == nil {
+		return false
+	}
+
+	csdb.journal.append(suicideChange{
+		account:     &addr,
+		prev:        so.suicided,
+		prevBalance: sdk.NewIntFromBigInt(so.Balance()),
+	})
+
+	so.markSuicided()
+	so.SetBalance(new(big.Int))
+
+	return true
+}
+
+// Reset clears out all ephemeral state objects from the state db, but keeps
+// the underlying account mapper and store keys to avoid reloading data for the
+// next operations.
+func (csdb *CommitStateDB) Reset(root ethcmn.Hash) error {
+	csdb.stateObjects = make(map[ethcmn.Address]*stateObject)
+	csdb.stateObjectsDirty = make(map[ethcmn.Address]struct{})
+	csdb.thash = ethcmn.Hash{}
+	csdb.bhash = ethcmn.Hash{}
+	csdb.txIndex = 0
+	csdb.logs = make(map[ethcmn.Hash][]*ethtypes.Log)
+	csdb.logSize = 0
+	csdb.preimages = make(map[ethcmn.Hash][]byte)
+
+	csdb.clearJournalAndRefund()
+	return nil
+}
+
+func (csdb *CommitStateDB) clearJournalAndRefund() {
+	csdb.journal = newJournal()
+	csdb.validRevisions = csdb.validRevisions[:0]
+	csdb.refund = 0
+}
+
+// Prepare sets the current transaction hash and index and block hash which is
+// used when the EVM emits new state logs.
+func (csdb *CommitStateDB) Prepare(thash, bhash ethcmn.Hash, txi int) {
+	csdb.thash = thash
+	csdb.bhash = bhash
+	csdb.txIndex = txi
+}
+
+// CreateAccount explicitly creates a state object. If a state object with the
+// address already exists the balance is carried over to the new account.
+//
+// CreateAccount is called during the EVM CREATE operation. The situation might
+// arise that a contract does the following:
+//
+//   1. sends funds to sha(account ++ (nonce + 1))
+//   2. tx_create(sha(account ++ nonce)) (note that this gets the address of 1)
+//
+// Carrying over the balance ensures that Ether doesn't disappear.
+func (csdb *CommitStateDB) CreateAccount(addr ethcmn.Address) {
+	newobj, prevobj := csdb.createObject(addr)
+	if prevobj != nil {
+		newobj.setBalance(sdk.NewIntFromBigInt(prevobj.Balance()))
+	}
+}
+
+// Copy creates a deep, independent copy of the state.
+//
+// NOTE: Snapshots of the copied state cannot be applied to the copy.
+func (csdb *CommitStateDB) Copy() ethstate.StateDB {
+	csdb.lock.Lock()
+	defer csdb.lock.Unlock()
+
+	// copy all the basic fields, initialize the memory ones
+	state := &CommitStateDB{
+		ctx:               csdb.ctx,
+		am:                csdb.am,
+		storageKey:        csdb.storageKey,
+		codeKey:           csdb.codeKey,
+		stateObjects:      make(map[ethcmn.Address]*stateObject, len(csdb.journal.dirties)),
+		stateObjectsDirty: make(map[ethcmn.Address]struct{}, len(csdb.journal.dirties)),
+		refund:            csdb.refund,
+		logs:              make(map[ethcmn.Hash][]*ethtypes.Log, len(csdb.logs)),
+		logSize:           csdb.logSize,
+		preimages:         make(map[ethcmn.Hash][]byte),
+		journal:           newJournal(),
+	}
+
+	// copy the dirty states, logs, and preimages
+	for addr := range csdb.journal.dirties {
+		// There is a case where an object is in the journal but not in the
+		// stateObjects: OOG after touch on ripeMD prior to Byzantium. Thus, we
+		// need to check for nil.
+		//
+		// Ref: https://github.com/ethereum/go-ethereum/pull/16485#issuecomment-380438527
+		if object, exist := csdb.stateObjects[addr]; exist {
+			state.stateObjects[addr] = object.deepCopy(state)
+			state.stateObjectsDirty[addr] = struct{}{}
+		}
+	}
+
+	// Above, we don't copy the actual journal. This means that if the copy is
+	// copied, the loop above will be a no-op, since the copy's journal is empty.
+	// Thus, here we iterate over stateObjects, to enable copies of copies.
+	for addr := range csdb.stateObjectsDirty {
+		if _, exist := state.stateObjects[addr]; !exist {
+			state.stateObjects[addr] = csdb.stateObjects[addr].deepCopy(state)
+			state.stateObjectsDirty[addr] = struct{}{}
+		}
+	}
+
+	// copy logs
+	for hash, logs := range csdb.logs {
+		cpy := make([]*ethtypes.Log, len(logs))
+		for i, l := range logs {
+			cpy[i] = new(ethtypes.Log)
+			*cpy[i] = *l
+		}
+		state.logs[hash] = cpy
+	}
+
+	// copy pre-images
+	for hash, preimage := range csdb.preimages {
+		state.preimages[hash] = preimage
+	}
+
+	return state
+}
+
+// ForEachStorage iterates over each storage items, all invokes the provided
+// callback on each key, value pair .
+func (csdb *CommitStateDB) ForEachStorage(addr ethcmn.Address, cb func(key, value ethcmn.Hash) bool) {
+	so := csdb.getStateObject(addr)
+	if so == nil {
+		return
+	}
+
+	store := csdb.ctx.KVStore(csdb.storageKey)
+	iter := sdk.KVStorePrefixIterator(store, so.Address().Bytes())
+
+	for ; iter.Valid(); iter.Next() {
+		key := ethcmn.BytesToHash(iter.Key())
+		value := iter.Value()
+
+		if value, dirty := so.dirtyStorage[key]; dirty {
+			cb(key, value)
+			continue
+		}
+
+		cb(key, ethcmn.BytesToHash(value))
+	}
+
+	iter.Close()
+}
+
+// GetOrNewStateObject retrieves a state object or create a new state object if
+// nil.
+func (csdb *CommitStateDB) GetOrNewStateObject(addr ethcmn.Address) ethstate.StateObject {
+	so := csdb.getStateObject(addr)
+	if so == nil || so.deleted {
+		so, _ = csdb.createObject(addr)
+	}
+
+	return so
+}
+
+// createObject creates a new state object. If there is an existing account with
+// the given address, it is overwritten and returned as the second return value.
+func (csdb *CommitStateDB) createObject(addr ethcmn.Address) (newObj, prevObj *stateObject) {
+	prevObj = csdb.getStateObject(addr)
+
+	acc := csdb.am.NewAccountWithAddress(csdb.ctx, sdk.AccAddress(addr.Bytes()))
+	newObj = newObject(csdb, acc)
+	newObj.setNonce(0) // sets the object to dirty
+
+	if prevObj == nil {
+		csdb.journal.append(createObjectChange{account: &addr})
+	} else {
+		csdb.journal.append(resetObjectChange{prev: prevObj})
+	}
+
+	csdb.setStateObject(newObj)
+	return newObj, prevObj
+}
+
+// setError remembers the first non-nil error it is called with.
+func (csdb *CommitStateDB) setError(err error) {
+	if csdb.dbErr == nil {
+		csdb.dbErr = err
+	}
+}
+
+// getStateObject attempts to retrieve a state object given by the address.
+// Returns nil and sets an error if not found.
+func (csdb *CommitStateDB) getStateObject(addr ethcmn.Address) (stateObject *stateObject) {
+	// prefer 'live' (cached) objects
+	if so := csdb.stateObjects[addr]; so != nil {
+		if so.deleted {
+			return nil
+		}
+
+		return so
+	}
+
+	// otherwise, attempt to fetch the account from the account mapper
+	acc := csdb.am.GetAccount(csdb.ctx, addr.Bytes())
+	if acc == nil {
+		csdb.setError(fmt.Errorf("no account found for address: %X", addr.Bytes()))
+		return nil
+	}
+
+	// insert the state object into the live set
+	so := newObject(csdb, acc)
+	csdb.setStateObject(so)
+
+	return so
+}
+
+func (csdb *CommitStateDB) setStateObject(so *stateObject) {
+	csdb.stateObjects[so.Address()] = so
+}