Official Go implementation of the Ethereum protocol
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go-ethereum/core/state/statedb.go

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// Copyright 2014 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
// Package state provides a caching layer atop the Ethereum state trie.
package state
import (
"errors"
"fmt"
"math/big"
"sort"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/metrics"
"github.com/ethereum/go-ethereum/rlp"
"github.com/ethereum/go-ethereum/trie"
)
type revision struct {
id int
journalIndex int
}
var (
// emptyRoot is the known root hash of an empty trie.
emptyRoot = common.HexToHash("56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421")
// emptyCode is the known hash of the empty EVM bytecode.
emptyCode = crypto.Keccak256Hash(nil)
)
type proofList [][]byte
func (n *proofList) Put(key []byte, value []byte) error {
*n = append(*n, value)
return nil
}
func (n *proofList) Delete(key []byte) error {
panic("not supported")
}
// StateDBs 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 {
db Database
trie Trie
// This map holds 'live' objects, which will get modified while processing a state transition.
stateObjects map[common.Address]*stateObject
stateObjectsPending map[common.Address]struct{} // State objects finalized but not yet written to the trie
stateObjectsDirty map[common.Address]struct{} // State objects modified in the current execution
// 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
// The refund counter, also used by state transitioning.
refund uint64
thash, bhash common.Hash
txIndex int
logs map[common.Hash][]*types.Log
logSize uint
preimages map[common.Hash][]byte
// Journal of state modifications. This is the backbone of
// Snapshot and RevertToSnapshot.
journal *journal
validRevisions []revision
nextRevisionId int
// Measurements gathered during execution for debugging purposes
AccountReads time.Duration
AccountHashes time.Duration
AccountUpdates time.Duration
AccountCommits time.Duration
StorageReads time.Duration
StorageHashes time.Duration
StorageUpdates time.Duration
StorageCommits time.Duration
}
// Create a new state from a given trie.
func New(root common.Hash, db Database) (*StateDB, error) {
tr, err := db.OpenTrie(root)
if err != nil {
return nil, err
}
return &StateDB{
db: db,
trie: tr,
stateObjects: make(map[common.Address]*stateObject),
stateObjectsPending: make(map[common.Address]struct{}),
stateObjectsDirty: make(map[common.Address]struct{}),
logs: make(map[common.Hash][]*types.Log),
preimages: make(map[common.Hash][]byte),
journal: newJournal(),
}, nil
}
// setError remembers the first non-nil error it is called with.
func (s *StateDB) setError(err error) {
if s.dbErr == nil {
s.dbErr = err
}
}
func (s *StateDB) Error() error {
return s.dbErr
}
// Reset clears out all ephemeral state objects from the state db, but keeps
// the underlying state trie to avoid reloading data for the next operations.
func (s *StateDB) Reset(root common.Hash) error {
tr, err := s.db.OpenTrie(root)
if err != nil {
return err
}
s.trie = tr
s.stateObjects = make(map[common.Address]*stateObject)
s.stateObjectsPending = make(map[common.Address]struct{})
s.stateObjectsDirty = make(map[common.Address]struct{})
s.thash = common.Hash{}
s.bhash = common.Hash{}
s.txIndex = 0
s.logs = make(map[common.Hash][]*types.Log)
s.logSize = 0
s.preimages = make(map[common.Hash][]byte)
s.clearJournalAndRefund()
return nil
}
func (s *StateDB) AddLog(log *types.Log) {
s.journal.append(addLogChange{txhash: s.thash})
log.TxHash = s.thash
log.BlockHash = s.bhash
log.TxIndex = uint(s.txIndex)
log.Index = s.logSize
s.logs[s.thash] = append(s.logs[s.thash], log)
s.logSize++
}
func (s *StateDB) GetLogs(hash common.Hash) []*types.Log {
return s.logs[hash]
}
func (s *StateDB) Logs() []*types.Log {
var logs []*types.Log
for _, lgs := range s.logs {
logs = append(logs, lgs...)
}
return logs
}
// AddPreimage records a SHA3 preimage seen by the VM.
func (s *StateDB) AddPreimage(hash common.Hash, preimage []byte) {
if _, ok := s.preimages[hash]; !ok {
s.journal.append(addPreimageChange{hash: hash})
pi := make([]byte, len(preimage))
copy(pi, preimage)
s.preimages[hash] = pi
}
}
// Preimages returns a list of SHA3 preimages that have been submitted.
func (s *StateDB) Preimages() map[common.Hash][]byte {
return s.preimages
}
// 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("Refund counter below zero")
}
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()
}
// Retrieve 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
}
func (s *StateDB) GetNonce(addr common.Address) uint64 {
stateObject := s.getStateObject(addr)
if stateObject != nil {
return stateObject.Nonce()
}
return 0
}
// TxIndex returns the current transaction index set by Prepare.
func (s *StateDB) TxIndex() int {
return s.txIndex
}
// BlockHash returns the current block hash set by Prepare.
func (s *StateDB) BlockHash() common.Hash {
return s.bhash
}
func (s *StateDB) GetCode(addr common.Address) []byte {
stateObject := s.getStateObject(addr)
if stateObject != nil {
return stateObject.Code(s.db)
}
return nil
}
func (s *StateDB) GetCodeSize(addr common.Address) int {
stateObject := s.getStateObject(addr)
if stateObject == nil {
return 0
}
if stateObject.code != nil {
return len(stateObject.code)
}
size, err := s.db.ContractCodeSize(stateObject.addrHash, common.BytesToHash(stateObject.CodeHash()))
if err != nil {
s.setError(err)
}
return size
}
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(s.db, hash)
}
return common.Hash{}
}
// GetProof returns the MerkleProof for a given Account
func (s *StateDB) GetProof(a common.Address) ([][]byte, error) {
var proof proofList
err := s.trie.Prove(crypto.Keccak256(a.Bytes()), 0, &proof)
return [][]byte(proof), err
}
// GetProof returns the StorageProof for given key
func (s *StateDB) GetStorageProof(a common.Address, key common.Hash) ([][]byte, error) {
var proof proofList
trie := s.StorageTrie(a)
if trie == nil {
return proof, errors.New("storage trie for requested address does not exist")
}
err := trie.Prove(crypto.Keccak256(key.Bytes()), 0, &proof)
return [][]byte(proof), err
}
// 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(s.db, hash)
}
return common.Hash{}
}
// Database retrieves the low level database supporting the lower level trie ops.
func (s *StateDB) Database() Database {
return s.db
}
// StorageTrie returns the storage trie of an account.
// The return value is a copy and is nil for non-existent accounts.
func (s *StateDB) StorageTrie(addr common.Address) Trie {
stateObject := s.getStateObject(addr)
if stateObject == nil {
return nil
}
cpy := stateObject.deepCopy(s)
return cpy.updateTrie(s.db)
}
func (s *StateDB) HasSuicided(addr common.Address) bool {
stateObject := s.getStateObject(addr)
if stateObject != nil {
return stateObject.suicided
}
return false
}
/*
* 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)
}
}
func (s *StateDB) SetBalance(addr common.Address, amount *big.Int) {
stateObject := s.GetOrNewStateObject(addr)
if stateObject != nil {
stateObject.SetBalance(amount)
}
}
func (s *StateDB) SetNonce(addr common.Address, nonce uint64) {
stateObject := s.GetOrNewStateObject(addr)
if stateObject != nil {
stateObject.SetNonce(nonce)
}
}
func (s *StateDB) SetCode(addr common.Address, code []byte) {
stateObject := s.GetOrNewStateObject(addr)
if stateObject != nil {
stateObject.SetCode(crypto.Keccak256Hash(code), code)
}
}
func (s *StateDB) SetState(addr common.Address, key, value common.Hash) {
stateObject := s.GetOrNewStateObject(addr)
if stateObject != nil {
stateObject.SetState(s.db, key, value)
}
}
// SetStorage replaces the entire storage for the specified account with given
// storage. This function should only be used for debugging.
func (s *StateDB) SetStorage(addr common.Address, storage map[common.Hash]common.Hash) {
stateObject := s.GetOrNewStateObject(addr)
if stateObject != nil {
stateObject.SetStorage(storage)
}
}
// 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.data.Balance = new(big.Int)
return true
}
//
// Setting, updating & deleting state object methods.
//
// updateStateObject writes the given object to the trie.
func (s *StateDB) updateStateObject(obj *stateObject) {
// Track the amount of time wasted on updating the account from the trie
if metrics.EnabledExpensive {
defer func(start time.Time) { s.AccountUpdates += time.Since(start) }(time.Now())
}
// Encode the account and update the account trie
addr := obj.Address()
data, err := rlp.EncodeToBytes(obj)
if err != nil {
panic(fmt.Errorf("can't encode object at %x: %v", addr[:], err))
}
s.setError(s.trie.TryUpdate(addr[:], data))
}
// deleteStateObject removes the given object from the state trie.
func (s *StateDB) deleteStateObject(obj *stateObject) {
// Track the amount of time wasted on deleting the account from the trie
if metrics.EnabledExpensive {
defer func(start time.Time) { s.AccountUpdates += time.Since(start) }(time.Now())
}
// Delete the account from the trie
addr := obj.Address()
s.setError(s.trie.TryDelete(addr[:]))
}
// getStateObject retrieves a state object given by the address, returning nil if
// the object is not found or was deleted in this execution context. If you need
// to differentiate between non-existent/just-deleted, use getDeletedStateObject.
func (s *StateDB) getStateObject(addr common.Address) *stateObject {
if obj := s.getDeletedStateObject(addr); obj != nil && !obj.deleted {
return obj
}
return nil
}
// getDeletedStateObject is similar to getStateObject, but instead of returning
// nil for a deleted state object, it returns the actual object with the deleted
// flag set. This is needed by the state journal to revert to the correct s-
// destructed object instead of wiping all knowledge about the state object.
func (s *StateDB) getDeletedStateObject(addr common.Address) *stateObject {
// Prefer live objects if any is available
if obj := s.stateObjects[addr]; obj != nil {
return obj
}
// Track the amount of time wasted on loading the object from the database
if metrics.EnabledExpensive {
defer func(start time.Time) { s.AccountReads += time.Since(start) }(time.Now())
}
// Load the object from the database
enc, err := s.trie.TryGet(addr[:])
if len(enc) == 0 {
s.setError(err)
return nil
}
var data Account
if err := rlp.DecodeBytes(enc, &data); err != nil {
log.Error("Failed to decode state object", "addr", addr, "err", err)
return nil
}
// Insert into the live set
obj := newObject(s, addr, data)
s.setStateObject(obj)
return obj
}
func (s *StateDB) setStateObject(object *stateObject) {
s.stateObjects[object.Address()] = object
}
// Retrieve 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.getDeletedStateObject(addr) // Note, prev might have been deleted, we need that!
newobj = newObject(s, addr, Account{})
newobj.setNonce(0) // sets the object to dirty
if prev == nil {
s.journal.append(createObjectChange{account: &addr})
} else {
s.journal.append(resetObjectChange{prev: prev})
}
s.setStateObject(newobj)
return newobj, prev
}
// 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.data.Balance)
}
}
func (db *StateDB) ForEachStorage(addr common.Address, cb func(key, value common.Hash) bool) error {
so := db.getStateObject(addr)
if so == nil {
return nil
}
it := trie.NewIterator(so.getTrie(db.db).NodeIterator(nil))
for it.Next() {
key := common.BytesToHash(db.trie.GetKey(it.Key))
if value, dirty := so.dirtyStorage[key]; dirty {
if !cb(key, value) {
return nil
}
continue
}
if len(it.Value) > 0 {
_, content, _, err := rlp.Split(it.Value)
if err != nil {
return err
}
if !cb(key, common.BytesToHash(content)) {
return nil
}
}
}
return nil
}
// Copy creates a deep, independent copy of the state.
// Snapshots of the copied state cannot be applied to the copy.
func (s *StateDB) Copy() *StateDB {
// Copy all the basic fields, initialize the memory ones
state := &StateDB{
db: s.db,
trie: s.db.CopyTrie(s.trie),
stateObjects: make(map[common.Address]*stateObject, len(s.journal.dirties)),
stateObjectsPending: make(map[common.Address]struct{}, len(s.stateObjectsPending)),
stateObjectsDirty: make(map[common.Address]struct{}, len(s.journal.dirties)),
refund: s.refund,
logs: make(map[common.Hash][]*types.Log, len(s.logs)),
logSize: s.logSize,
preimages: make(map[common.Hash][]byte, len(s.preimages)),
journal: newJournal(),
}
// Copy the dirty states, logs, and preimages
for addr := range s.journal.dirties {
// As documented [here](https://github.com/ethereum/go-ethereum/pull/16485#issuecomment-380438527),
// and in the Finalise-method, 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
if object, exist := s.stateObjects[addr]; exist {
// Even though the original object is dirty, we are not copying the journal,
// so we need to make sure that anyside effect the journal would have caused
// during a commit (or similar op) is already applied to the copy.
state.stateObjects[addr] = object.deepCopy(state)
state.stateObjectsDirty[addr] = struct{}{} // Mark the copy dirty to force internal (code/state) commits
state.stateObjectsPending[addr] = struct{}{} // Mark the copy pending to force external (account) commits
}
}
// 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 s.stateObjectsPending {
if _, exist := state.stateObjects[addr]; !exist {
state.stateObjects[addr] = s.stateObjects[addr].deepCopy(state)
}
state.stateObjectsPending[addr] = struct{}{}
}
for addr := range s.stateObjectsDirty {
if _, exist := state.stateObjects[addr]; !exist {
state.stateObjects[addr] = s.stateObjects[addr].deepCopy(state)
}
state.stateObjectsDirty[addr] = struct{}{}
}
for hash, logs := range s.logs {
cpy := make([]*types.Log, len(logs))
for i, l := range logs {
cpy[i] = new(types.Log)
*cpy[i] = *l
}
state.logs[hash] = cpy
}
for hash, preimage := range s.preimages {
state.preimages[hash] = preimage
}
return state
}
// 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]
}
// GetRefund returns the current value of the refund counter.
func (s *StateDB) GetRefund() uint64 {
return s.refund
}
// Finalise finalises the state by removing the s destructed objects and clears
// the journal as well as the refunds. Finalise, however, will not push any updates
// into the tries just yet. Only IntermediateRoot or Commit will do that.
func (s *StateDB) Finalise(deleteEmptyObjects bool) {
for addr := range s.journal.dirties {
obj, exist := s.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 `s.journal.dirties` but not in `s.stateObjects`.
// Thus, we can safely ignore it here
continue
}
if obj.suicided || (deleteEmptyObjects && obj.empty()) {
obj.deleted = true
} else {
obj.finalise()
}
s.stateObjectsPending[addr] = struct{}{}
s.stateObjectsDirty[addr] = struct{}{}
}
// Invalidate journal because reverting across transactions is not allowed.
s.clearJournalAndRefund()
}
// IntermediateRoot computes the current root hash of the state trie.
// It is called in between transactions to get the root hash that
// goes into transaction receipts.
func (s *StateDB) IntermediateRoot(deleteEmptyObjects bool) common.Hash {
// Finalise all the dirty storage states and write them into the tries
s.Finalise(deleteEmptyObjects)
for addr := range s.stateObjectsPending {
obj := s.stateObjects[addr]
if obj.deleted {
s.deleteStateObject(obj)
} else {
obj.updateRoot(s.db)
s.updateStateObject(obj)
}
}
if len(s.stateObjectsPending) > 0 {
s.stateObjectsPending = make(map[common.Address]struct{})
}
// Track the amount of time wasted on hashing the account trie
if metrics.EnabledExpensive {
defer func(start time.Time) { s.AccountHashes += time.Since(start) }(time.Now())
}
return s.trie.Hash()
}
// Prepare sets the current transaction hash and index and block hash which is
// used when the EVM emits new state logs.
func (s *StateDB) Prepare(thash, bhash common.Hash, ti int) {
s.thash = thash
s.bhash = bhash
s.txIndex = ti
}
func (s *StateDB) clearJournalAndRefund() {
if len(s.journal.entries) > 0 {
s.journal = newJournal()
s.refund = 0
}
s.validRevisions = s.validRevisions[:0] // Snapshots can be created without journal entires
}
// Commit writes the state to the underlying in-memory trie database.
func (s *StateDB) Commit(deleteEmptyObjects bool) (common.Hash, error) {
// Finalize any pending changes and merge everything into the tries
s.IntermediateRoot(deleteEmptyObjects)
// Commit objects to the trie, measuring the elapsed time
for addr := range s.stateObjectsDirty {
if obj := s.stateObjects[addr]; !obj.deleted {
// Write any contract code associated with the state object
if obj.code != nil && obj.dirtyCode {
s.db.TrieDB().InsertBlob(common.BytesToHash(obj.CodeHash()), obj.code)
obj.dirtyCode = false
}
// Write any storage changes in the state object to its storage trie
if err := obj.CommitTrie(s.db); err != nil {
return common.Hash{}, err
}
}
}
if len(s.stateObjectsDirty) > 0 {
s.stateObjectsDirty = make(map[common.Address]struct{})
}
// Write the account trie changes, measuing the amount of wasted time
if metrics.EnabledExpensive {
defer func(start time.Time) { s.AccountCommits += time.Since(start) }(time.Now())
}
return s.trie.Commit(func(leaf []byte, parent common.Hash) error {
var account Account
if err := rlp.DecodeBytes(leaf, &account); err != nil {
return nil
}
if account.Root != emptyRoot {
s.db.TrieDB().Reference(account.Root, parent)
}
code := common.BytesToHash(account.CodeHash)
if code != emptyCode {
s.db.TrieDB().Reference(code, parent)
}
return nil
})
}