laconicd/x/evm/statedb/statedb.go
yihuang e6c9b7723b
evm: improve test coverage of statedb package (#888)
Closes: #876
- coverage: 99.3% of statements
2022-01-06 18:10:51 +01:00

464 lines
14 KiB
Go

package statedb
import (
"fmt"
"math/big"
"sort"
sdk "github.com/cosmos/cosmos-sdk/types"
sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
"github.com/ethereum/go-ethereum/common"
ethtypes "github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/core/vm"
"github.com/ethereum/go-ethereum/crypto"
)
// revision is the identifier of a version of state.
// it consists of an auto-increment id and a journal index.
// it's safer to use than using journal index alone.
type revision struct {
id int
journalIndex int
}
var _ vm.StateDB = &StateDB{}
// StateDB structs within the ethereum protocol are used to store anything
// within the merkle trie. StateDBs take care of caching and storing
// nested states. It's the general query interface to retrieve:
// * Contracts
// * Accounts
type StateDB struct {
keeper Keeper
ctx sdk.Context
// Journal of state modifications. This is the backbone of
// Snapshot and RevertToSnapshot.
journal *journal
validRevisions []revision
nextRevisionID int
stateObjects map[common.Address]*stateObject
txConfig TxConfig
// The refund counter, also used by state transitioning.
refund uint64
// Per-transaction logs
logs []*ethtypes.Log
// Per-transaction access list
accessList *accessList
}
// New creates a new state from a given trie.
func New(ctx sdk.Context, keeper Keeper, txConfig TxConfig) *StateDB {
return &StateDB{
keeper: keeper,
ctx: ctx,
stateObjects: make(map[common.Address]*stateObject),
journal: newJournal(),
accessList: newAccessList(),
txConfig: txConfig,
}
}
// Keeper returns the underlying `Keeper`
func (s *StateDB) Keeper() Keeper {
return s.keeper
}
// AddLog adds a log, called by evm.
func (s *StateDB) AddLog(log *ethtypes.Log) {
s.journal.append(addLogChange{})
log.TxHash = s.txConfig.TxHash
log.BlockHash = s.txConfig.BlockHash
log.TxIndex = s.txConfig.TxIndex
log.Index = s.txConfig.LogIndex + uint(len(s.logs))
s.logs = append(s.logs, log)
}
// Logs returns the logs of current transaction.
func (s *StateDB) Logs() []*ethtypes.Log {
return s.logs
}
// AddRefund adds gas to the refund counter
func (s *StateDB) AddRefund(gas uint64) {
s.journal.append(refundChange{prev: s.refund})
s.refund += gas
}
// SubRefund removes gas from the refund counter.
// This method will panic if the refund counter goes below zero
func (s *StateDB) SubRefund(gas uint64) {
s.journal.append(refundChange{prev: s.refund})
if gas > s.refund {
panic(fmt.Sprintf("Refund counter below zero (gas: %d > refund: %d)", gas, s.refund))
}
s.refund -= gas
}
// Exist reports whether the given account address exists in the state.
// Notably this also returns true for suicided accounts.
func (s *StateDB) Exist(addr common.Address) bool {
return s.getStateObject(addr) != nil
}
// Empty returns whether the state object is either non-existent
// or empty according to the EIP161 specification (balance = nonce = code = 0)
func (s *StateDB) Empty(addr common.Address) bool {
so := s.getStateObject(addr)
return so == nil || so.empty()
}
// GetBalance retrieves the balance from the given address or 0 if object not found
func (s *StateDB) GetBalance(addr common.Address) *big.Int {
stateObject := s.getStateObject(addr)
if stateObject != nil {
return stateObject.Balance()
}
return common.Big0
}
// GetNonce returns the nonce of account, 0 if not exists.
func (s *StateDB) GetNonce(addr common.Address) uint64 {
stateObject := s.getStateObject(addr)
if stateObject != nil {
return stateObject.Nonce()
}
return 0
}
// GetCode returns the code of account, nil if not exists.
func (s *StateDB) GetCode(addr common.Address) []byte {
stateObject := s.getStateObject(addr)
if stateObject != nil {
return stateObject.Code()
}
return nil
}
// GetCodeSize returns the code size of account.
func (s *StateDB) GetCodeSize(addr common.Address) int {
stateObject := s.getStateObject(addr)
if stateObject != nil {
return stateObject.CodeSize()
}
return 0
}
// GetCodeHash returns the code hash of account.
func (s *StateDB) GetCodeHash(addr common.Address) common.Hash {
stateObject := s.getStateObject(addr)
if stateObject == nil {
return common.Hash{}
}
return common.BytesToHash(stateObject.CodeHash())
}
// GetState retrieves a value from the given account's storage trie.
func (s *StateDB) GetState(addr common.Address, hash common.Hash) common.Hash {
stateObject := s.getStateObject(addr)
if stateObject != nil {
return stateObject.GetState(hash)
}
return common.Hash{}
}
// GetCommittedState retrieves a value from the given account's committed storage trie.
func (s *StateDB) GetCommittedState(addr common.Address, hash common.Hash) common.Hash {
stateObject := s.getStateObject(addr)
if stateObject != nil {
return stateObject.GetCommittedState(hash)
}
return common.Hash{}
}
// GetRefund returns the current value of the refund counter.
func (s *StateDB) GetRefund() uint64 {
return s.refund
}
// HasSuicided returns if the contract is suicided in current transaction.
func (s *StateDB) HasSuicided(addr common.Address) bool {
stateObject := s.getStateObject(addr)
if stateObject != nil {
return stateObject.suicided
}
return false
}
// AddPreimage records a SHA3 preimage seen by the VM.
// AddPreimage performs a no-op since the EnablePreimageRecording flag is disabled
// on the vm.Config during state transitions. No store trie preimages are written
// to the database.
func (s *StateDB) AddPreimage(hash common.Hash, preimage []byte) {}
// getStateObject retrieves a state object given by the address, returning nil if
// the object is not found.
func (s *StateDB) getStateObject(addr common.Address) *stateObject {
// Prefer live objects if any is available
if obj := s.stateObjects[addr]; obj != nil {
return obj
}
// If no live objects are available, load it from keeper
account := s.keeper.GetAccount(s.ctx, addr)
if account == nil {
return nil
}
// Insert into the live set
obj := newObject(s, addr, *account)
s.setStateObject(obj)
return obj
}
// getOrNewStateObject retrieves a state object or create a new state object if nil.
func (s *StateDB) getOrNewStateObject(addr common.Address) *stateObject {
stateObject := s.getStateObject(addr)
if stateObject == nil {
stateObject, _ = s.createObject(addr)
}
return stateObject
}
// 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 (s *StateDB) createObject(addr common.Address) (newobj, prev *stateObject) {
prev = s.getStateObject(addr)
newobj = newObject(s, addr, Account{})
if prev == nil {
s.journal.append(createObjectChange{account: &addr})
} else {
s.journal.append(resetObjectChange{prev: prev})
}
s.setStateObject(newobj)
if prev != nil {
return newobj, prev
}
return newobj, nil
}
// 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 (s *StateDB) CreateAccount(addr common.Address) {
newObj, prev := s.createObject(addr)
if prev != nil {
newObj.setBalance(prev.account.Balance)
}
}
// ForEachStorage iterate the contract storage, the iteration order is not defined.
func (s *StateDB) ForEachStorage(addr common.Address, cb func(key, value common.Hash) bool) error {
so := s.getStateObject(addr)
if so == nil {
return nil
}
s.keeper.ForEachStorage(s.ctx, addr, func(key, value common.Hash) bool {
if value, dirty := so.dirtyStorage[key]; dirty {
return cb(key, value)
}
if len(value) > 0 {
return cb(key, value)
}
return true
})
return nil
}
func (s *StateDB) setStateObject(object *stateObject) {
s.stateObjects[object.Address()] = object
}
/*
* SETTERS
*/
// AddBalance adds amount to the account associated with addr.
func (s *StateDB) AddBalance(addr common.Address, amount *big.Int) {
stateObject := s.getOrNewStateObject(addr)
if stateObject != nil {
stateObject.AddBalance(amount)
}
}
// SubBalance subtracts amount from the account associated with addr.
func (s *StateDB) SubBalance(addr common.Address, amount *big.Int) {
stateObject := s.getOrNewStateObject(addr)
if stateObject != nil {
stateObject.SubBalance(amount)
}
}
// SetNonce sets the nonce of account.
func (s *StateDB) SetNonce(addr common.Address, nonce uint64) {
stateObject := s.getOrNewStateObject(addr)
if stateObject != nil {
stateObject.SetNonce(nonce)
}
}
// SetCode sets the code of account.
func (s *StateDB) SetCode(addr common.Address, code []byte) {
stateObject := s.getOrNewStateObject(addr)
if stateObject != nil {
stateObject.SetCode(crypto.Keccak256Hash(code), code)
}
}
// SetState sets the contract state.
func (s *StateDB) SetState(addr common.Address, key, value common.Hash) {
stateObject := s.getOrNewStateObject(addr)
if stateObject != nil {
stateObject.SetState(key, value)
}
}
// Suicide marks the given account as suicided.
// This 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 (s *StateDB) Suicide(addr common.Address) bool {
stateObject := s.getStateObject(addr)
if stateObject == nil {
return false
}
s.journal.append(suicideChange{
account: &addr,
prev: stateObject.suicided,
prevbalance: new(big.Int).Set(stateObject.Balance()),
})
stateObject.markSuicided()
stateObject.account.Balance = new(big.Int)
return true
}
// PrepareAccessList handles the preparatory steps for executing a state transition with
// regards to both EIP-2929 and EIP-2930:
//
// - Add sender to access list (2929)
// - Add destination to access list (2929)
// - Add precompiles to access list (2929)
// - Add the contents of the optional tx access list (2930)
//
// This method should only be called if Yolov3/Berlin/2929+2930 is applicable at the current number.
func (s *StateDB) PrepareAccessList(sender common.Address, dst *common.Address, precompiles []common.Address, list ethtypes.AccessList) {
s.AddAddressToAccessList(sender)
if dst != nil {
s.AddAddressToAccessList(*dst)
// If it's a create-tx, the destination will be added inside evm.create
}
for _, addr := range precompiles {
s.AddAddressToAccessList(addr)
}
for _, el := range list {
s.AddAddressToAccessList(el.Address)
for _, key := range el.StorageKeys {
s.AddSlotToAccessList(el.Address, key)
}
}
}
// AddAddressToAccessList adds the given address to the access list
func (s *StateDB) AddAddressToAccessList(addr common.Address) {
if s.accessList.AddAddress(addr) {
s.journal.append(accessListAddAccountChange{&addr})
}
}
// AddSlotToAccessList adds the given (address, slot)-tuple to the access list
func (s *StateDB) AddSlotToAccessList(addr common.Address, slot common.Hash) {
addrMod, slotMod := s.accessList.AddSlot(addr, slot)
if addrMod {
// In practice, this should not happen, since there is no way to enter the
// scope of 'address' without having the 'address' become already added
// to the access list (via call-variant, create, etc).
// Better safe than sorry, though
s.journal.append(accessListAddAccountChange{&addr})
}
if slotMod {
s.journal.append(accessListAddSlotChange{
address: &addr,
slot: &slot,
})
}
}
// AddressInAccessList returns true if the given address is in the access list.
func (s *StateDB) AddressInAccessList(addr common.Address) bool {
return s.accessList.ContainsAddress(addr)
}
// SlotInAccessList returns true if the given (address, slot)-tuple is in the access list.
func (s *StateDB) SlotInAccessList(addr common.Address, slot common.Hash) (addressPresent bool, slotPresent bool) {
return s.accessList.Contains(addr, slot)
}
// Snapshot returns an identifier for the current revision of the state.
func (s *StateDB) Snapshot() int {
id := s.nextRevisionID
s.nextRevisionID++
s.validRevisions = append(s.validRevisions, revision{id, s.journal.length()})
return id
}
// RevertToSnapshot reverts all state changes made since the given revision.
func (s *StateDB) RevertToSnapshot(revid int) {
// Find the snapshot in the stack of valid snapshots.
idx := sort.Search(len(s.validRevisions), func(i int) bool {
return s.validRevisions[i].id >= revid
})
if idx == len(s.validRevisions) || s.validRevisions[idx].id != revid {
panic(fmt.Errorf("revision id %v cannot be reverted", revid))
}
snapshot := s.validRevisions[idx].journalIndex
// Replay the journal to undo changes and remove invalidated snapshots
s.journal.revert(s, snapshot)
s.validRevisions = s.validRevisions[:idx]
}
// Commit writes the dirty states to keeper
// the StateDB object should be discarded after committed.
func (s *StateDB) Commit() error {
for _, addr := range s.journal.sortedDirties() {
obj := s.stateObjects[addr]
if obj.suicided {
if err := s.keeper.DeleteAccount(s.ctx, obj.Address()); err != nil {
return sdkerrors.Wrap(err, "failed to delete account")
}
} else {
if obj.code != nil && obj.dirtyCode {
s.keeper.SetCode(s.ctx, obj.CodeHash(), obj.code)
}
if err := s.keeper.SetAccount(s.ctx, obj.Address(), obj.account); err != nil {
return sdkerrors.Wrap(err, "failed to set account")
}
for _, key := range obj.dirtyStorage.SortedKeys() {
value := obj.dirtyStorage[key]
// Skip noop changes, persist actual changes
if value == obj.originStorage[key] {
continue
}
s.keeper.SetState(s.ctx, obj.Address(), key, value.Bytes())
}
}
}
return nil
}