Official Go implementation of the Ethereum protocol
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go-ethereum/core/state/state_object.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/>.
10 years ago
package state
import (
"bytes"
"fmt"
"maps"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/tracing"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/rlp"
"github.com/ethereum/go-ethereum/trie/trienode"
"github.com/holiman/uint256"
)
type Storage map[common.Hash]common.Hash
func (s Storage) Copy() Storage {
return maps.Clone(s)
}
// 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 as well as storages can be accessed and modified through the object.
// - Finally, call commit to return the changes of storage trie and update account data.
type stateObject struct {
db *StateDB
address common.Address // address of ethereum account
addrHash common.Hash // hash of ethereum address of the account
origin *types.StateAccount // Account original data without any change applied, nil means it was not existent
data types.StateAccount // Account data with all mutations applied in the scope of block
// Write caches.
trie Trie // storage trie, which becomes non-nil on first access
code []byte // contract bytecode, which gets set when code is loaded
originStorage Storage // Storage entries that have been accessed within the current block
dirtyStorage Storage // Storage entries that have been modified within the current transaction
pendingStorage Storage // Storage entries that have been modified within the current block
// uncommittedStorage tracks a set of storage entries that have been modified
// but not yet committed since the "last commit operation", along with their
// original values before mutation.
//
// Specifically, the commit will be performed after each transaction before
// the byzantium fork, therefore the map is already reset at the transaction
// boundary; however post the byzantium fork, the commit will only be performed
// at the end of block, this set essentially tracks all the modifications
// made within the block.
uncommittedStorage Storage
// Cache flags.
dirtyCode bool // true if the code was updated
// Flag whether the account was marked as self-destructed. The self-destructed
// account is still accessible in the scope of same transaction.
selfDestructed bool
// This is an EIP-6780 flag indicating whether the object is eligible for
// self-destruct according to EIP-6780. The flag could be set either when
// the contract is just created within the current transaction, or when the
// object was previously existent and is being deployed as a contract within
// the current transaction.
newContract bool
}
// empty returns whether the account is considered empty.
func (s *stateObject) empty() bool {
return s.data.Nonce == 0 && s.data.Balance.IsZero() && bytes.Equal(s.data.CodeHash, types.EmptyCodeHash.Bytes())
}
// newObject creates a state object.
func newObject(db *StateDB, address common.Address, acct *types.StateAccount) *stateObject {
origin := acct
if acct == nil {
acct = types.NewEmptyStateAccount()
}
return &stateObject{
db: db,
address: address,
addrHash: crypto.Keccak256Hash(address[:]),
origin: origin,
data: *acct,
originStorage: make(Storage),
dirtyStorage: make(Storage),
pendingStorage: make(Storage),
uncommittedStorage: make(Storage),
}
}
func (s *stateObject) markSelfdestructed() {
s.selfDestructed = true
}
func (s *stateObject) touch() {
s.db.journal.append(touchChange{
account: &s.address,
})
if s.address == ripemd {
// Explicitly put it in the dirty-cache, which is otherwise generated from
// flattened journals.
s.db.journal.dirty(s.address)
}
}
// getTrie returns the associated storage trie. The trie will be opened if it's
// not loaded previously. An error will be returned if trie can't be loaded.
//
// If a new trie is opened, it will be cached within the state object to allow
// subsequent reads to expand the same trie instead of reloading from disk.
func (s *stateObject) getTrie() (Trie, error) {
if s.trie == nil {
tr, err := s.db.db.OpenStorageTrie(s.db.originalRoot, s.address, s.data.Root, s.db.trie)
if err != nil {
return nil, err
}
s.trie = tr
}
return s.trie, nil
}
// getPrefetchedTrie returns the associated trie, as populated by the prefetcher
// if it's available.
//
// Note, opposed to getTrie, this method will *NOT* blindly cache the resulting
// trie in the state object. The caller might want to do that, but it's cleaner
// to break the hidden interdependency between retrieving tries from the db or
// from the prefetcher.
func (s *stateObject) getPrefetchedTrie() Trie {
// If there's nothing to meaningfully return, let the user figure it out by
// pulling the trie from disk.
if s.data.Root == types.EmptyRootHash || s.db.prefetcher == nil {
return nil
}
// Attempt to retrieve the trie from the prefetcher
return s.db.prefetcher.trie(s.addrHash, s.data.Root)
}
// GetState retrieves a value associated with the given storage key.
func (s *stateObject) GetState(key common.Hash) common.Hash {
value, _ := s.getState(key)
return value
}
// getState retrieves a value associated with the given storage key, along with
// its original value.
func (s *stateObject) getState(key common.Hash) (common.Hash, common.Hash) {
origin := s.GetCommittedState(key)
value, dirty := s.dirtyStorage[key]
if dirty {
return value, origin
}
return origin, origin
}
// GetCommittedState retrieves the value associated with the specific key
// without any mutations caused in the current execution.
func (s *stateObject) GetCommittedState(key common.Hash) common.Hash {
// If we have a pending write or clean cached, return that
if value, pending := s.pendingStorage[key]; pending {
return value
}
if value, cached := s.originStorage[key]; cached {
return value
}
// If the object was destructed in *this* block (and potentially resurrected),
// the storage has been cleared out, and we should *not* consult the previous
// database about any storage values. The only possible alternatives are:
// 1) resurrect happened, and new slot values were set -- those should
// have been handles via pendingStorage above.
// 2) we don't have new values, and can deliver empty response back
if _, destructed := s.db.stateObjectsDestruct[s.address]; destructed {
s.originStorage[key] = common.Hash{} // track the empty slot as origin value
return common.Hash{}
}
// If no live objects are available, attempt to use snapshots
var (
enc []byte
err error
value common.Hash
)
if s.db.snap != nil {
start := time.Now()
enc, err = s.db.snap.Storage(s.addrHash, crypto.Keccak256Hash(key.Bytes()))
s.db.SnapshotStorageReads += time.Since(start)
if len(enc) > 0 {
_, content, _, err := rlp.Split(enc)
if err != nil {
s.db.setError(err)
}
value.SetBytes(content)
}
}
// If the snapshot is unavailable or reading from it fails, load from the database.
if s.db.snap == nil || err != nil {
start := time.Now()
tr, err := s.getTrie()
if err != nil {
s.db.setError(err)
return common.Hash{}
}
val, err := tr.GetStorage(s.address, key.Bytes())
s.db.StorageReads += time.Since(start)
if err != nil {
s.db.setError(err)
return common.Hash{}
}
value.SetBytes(val)
}
// Independent of where we loaded the data from, add it to the prefetcher.
// Whilst this would be a bit weird if snapshots are disabled, but we still
// want the trie nodes to end up in the prefetcher too, so just push through.
if s.db.prefetcher != nil && s.data.Root != types.EmptyRootHash {
if err = s.db.prefetcher.prefetch(s.addrHash, s.origin.Root, s.address, [][]byte{key[:]}, true); err != nil {
log.Error("Failed to prefetch storage slot", "addr", s.address, "key", key, "err", err)
}
}
s.originStorage[key] = value
return value
}
// SetState updates a value in account storage.
func (s *stateObject) SetState(key, value common.Hash) {
// If the new value is the same as old, don't set. Otherwise, track only the
// dirty changes, supporting reverting all of it back to no change.
prev, origin := s.getState(key)
if prev == value {
return
}
// New value is different, update and journal the change
s.db.journal.append(storageChange{
account: &s.address,
key: key,
prevvalue: prev,
origvalue: origin,
})
if s.db.logger != nil && s.db.logger.OnStorageChange != nil {
s.db.logger.OnStorageChange(s.address, key, prev, value)
}
s.setState(key, value, origin)
}
// setState updates a value in account dirty storage. The dirtiness will be
// removed if the value being set equals to the original value.
func (s *stateObject) setState(key common.Hash, value common.Hash, origin common.Hash) {
// Storage slot is set back to its original value, undo the dirty marker
if value == origin {
delete(s.dirtyStorage, key)
return
}
s.dirtyStorage[key] = value
}
// finalise moves all dirty storage slots into the pending area to be hashed or
// committed later. It is invoked at the end of every transaction.
func (s *stateObject) finalise() {
slotsToPrefetch := make([][]byte, 0, len(s.dirtyStorage))
for key, value := range s.dirtyStorage {
if origin, exist := s.uncommittedStorage[key]; exist && origin == value {
// The slot is reverted to its original value, delete the entry
// to avoid thrashing the data structures.
delete(s.uncommittedStorage, key)
} else if exist {
// The slot is modified to another value and the slot has been
// tracked for commit, do nothing here.
} else {
// The slot is different from its original value and hasn't been
// tracked for commit yet.
s.uncommittedStorage[key] = s.GetCommittedState(key)
slotsToPrefetch = append(slotsToPrefetch, common.CopyBytes(key[:])) // Copy needed for closure
}
// Aggregate the dirty storage slots into the pending area. It might
// be possible that the value of tracked slot here is same with the
// one in originStorage (e.g. the slot was modified in tx_a and then
// modified back in tx_b). We can't blindly remove it from pending
// map as the dirty slot might have been committed already (before the
// byzantium fork) and entry is necessary to modify the value back.
s.pendingStorage[key] = value
}
if s.db.prefetcher != nil && len(slotsToPrefetch) > 0 && s.data.Root != types.EmptyRootHash {
if err := s.db.prefetcher.prefetch(s.addrHash, s.data.Root, s.address, slotsToPrefetch, false); err != nil {
log.Error("Failed to prefetch slots", "addr", s.address, "slots", len(slotsToPrefetch), "err", err)
}
}
if len(s.dirtyStorage) > 0 {
s.dirtyStorage = make(Storage)
}
// Revoke the flag at the end of the transaction. It finalizes the status
// of the newly-created object as it's no longer eligible for self-destruct
// by EIP-6780. For non-newly-created objects, it's a no-op.
s.newContract = false
}
// updateTrie is responsible for persisting cached storage changes into the
// object's storage trie. In case the storage trie is not yet loaded, this
// function will load the trie automatically. If any issues arise during the
// loading or updating of the trie, an error will be returned. Furthermore,
// this function will return the mutated storage trie, or nil if there is no
// storage change at all.
//
// It assumes all the dirty storage slots have been finalized before.
func (s *stateObject) updateTrie() (Trie, error) {
// Short circuit if nothing changed, don't bother with hashing anything
if len(s.uncommittedStorage) == 0 {
return s.trie, nil
}
// Retrieve a pretecher populated trie, or fall back to the database
tr := s.getPrefetchedTrie()
if tr != nil {
// Prefetcher returned a live trie, swap it out for the current one
s.trie = tr
} else {
// Fetcher not running or empty trie, fallback to the database trie
var err error
tr, err = s.getTrie()
if err != nil {
s.db.setError(err)
return nil, err
}
}
// Perform trie updates before deletions. This prevents resolution of unnecessary trie nodes
// in circumstances similar to the following:
//
// Consider nodes `A` and `B` who share the same full node parent `P` and have no other siblings.
// During the execution of a block:
// - `A` is deleted,
// - `C` is created, and also shares the parent `P`.
// If the deletion is handled first, then `P` would be left with only one child, thus collapsed
// into a shortnode. This requires `B` to be resolved from disk.
// Whereas if the created node is handled first, then the collapse is avoided, and `B` is not resolved.
var (
deletions []common.Hash
used = make([][]byte, 0, len(s.uncommittedStorage))
)
for key, origin := range s.uncommittedStorage {
// Skip noop changes, persist actual changes
value, exist := s.pendingStorage[key]
if value == origin {
log.Error("Storage update was noop", "address", s.address, "slot", key)
continue
}
if !exist {
log.Error("Storage slot is not found in pending area", s.address, "slot", key)
continue
}
if (value != common.Hash{}) {
if err := tr.UpdateStorage(s.address, key[:], common.TrimLeftZeroes(value[:])); err != nil {
s.db.setError(err)
return nil, err
}
s.db.StorageUpdated.Add(1)
} else {
deletions = append(deletions, key)
}
// Cache the items for preloading
used = append(used, common.CopyBytes(key[:])) // Copy needed for closure
}
for _, key := range deletions {
if err := tr.DeleteStorage(s.address, key[:]); err != nil {
s.db.setError(err)
return nil, err
}
s.db.StorageDeleted.Add(1)
}
if s.db.prefetcher != nil {
s.db.prefetcher.used(s.addrHash, s.data.Root, used)
}
s.uncommittedStorage = make(Storage) // empties the commit markers
return tr, nil
}
// updateRoot flushes all cached storage mutations to trie, recalculating the
// new storage trie root.
func (s *stateObject) updateRoot() {
// Flush cached storage mutations into trie, short circuit if any error
// is occurred or there is no change in the trie.
tr, err := s.updateTrie()
if err != nil || tr == nil {
return
}
s.data.Root = tr.Hash()
}
// commitStorage overwrites the clean storage with the storage changes and
// fulfills the storage diffs into the given accountUpdate struct.
func (s *stateObject) commitStorage(op *accountUpdate) {
var (
buf = crypto.NewKeccakState()
encode = func(val common.Hash) []byte {
if val == (common.Hash{}) {
return nil
}
blob, _ := rlp.EncodeToBytes(common.TrimLeftZeroes(val[:]))
return blob
}
)
for key, val := range s.pendingStorage {
// Skip the noop storage changes, it might be possible the value
// of tracked slot is same in originStorage and pendingStorage
// map, e.g. the storage slot is modified in tx_a and then reset
// back in tx_b.
if val == s.originStorage[key] {
continue
}
hash := crypto.HashData(buf, key[:])
if op.storages == nil {
op.storages = make(map[common.Hash][]byte)
}
op.storages[hash] = encode(val)
if op.storagesOrigin == nil {
op.storagesOrigin = make(map[common.Hash][]byte)
}
op.storagesOrigin[hash] = encode(s.originStorage[key])
// Overwrite the clean value of storage slots
s.originStorage[key] = val
}
s.pendingStorage = make(Storage)
}
// commit obtains the account changes (metadata, storage slots, code) caused by
// state execution along with the dirty storage trie nodes.
//
// Note, commit may run concurrently across all the state objects. Do not assume
// thread-safe access to the statedb.
func (s *stateObject) commit() (*accountUpdate, *trienode.NodeSet, error) {
// commit the account metadata changes
op := &accountUpdate{
address: s.address,
data: types.SlimAccountRLP(s.data),
}
if s.origin != nil {
op.origin = types.SlimAccountRLP(*s.origin)
}
// commit the contract code if it's modified
if s.dirtyCode {
op.code = &contractCode{
hash: common.BytesToHash(s.CodeHash()),
blob: s.code,
}
s.dirtyCode = false // reset the dirty flag
}
// Commit storage changes and the associated storage trie
s.commitStorage(op)
if len(op.storages) == 0 {
// nothing changed, don't bother to commit the trie
s.origin = s.data.Copy()
return op, nil, nil
}
root, nodes := s.trie.Commit(false)
s.data.Root = root
s.origin = s.data.Copy()
return op, nodes, nil
}
// AddBalance adds amount to s's balance.
// It is used to add funds to the destination account of a transfer.
func (s *stateObject) AddBalance(amount *uint256.Int, reason tracing.BalanceChangeReason) {
// EIP161: We must check emptiness for the objects such that the account
// clearing (0,0,0 objects) can take effect.
if amount.IsZero() {
if s.empty() {
s.touch()
}
return
}
s.SetBalance(new(uint256.Int).Add(s.Balance(), amount), reason)
}
// SubBalance removes amount from s's balance.
// It is used to remove funds from the origin account of a transfer.
func (s *stateObject) SubBalance(amount *uint256.Int, reason tracing.BalanceChangeReason) {
if amount.IsZero() {
return
}
s.SetBalance(new(uint256.Int).Sub(s.Balance(), amount), reason)
}
func (s *stateObject) SetBalance(amount *uint256.Int, reason tracing.BalanceChangeReason) {
s.db.journal.append(balanceChange{
account: &s.address,
prev: new(uint256.Int).Set(s.data.Balance),
})
if s.db.logger != nil && s.db.logger.OnBalanceChange != nil {
s.db.logger.OnBalanceChange(s.address, s.Balance().ToBig(), amount.ToBig(), reason)
}
s.setBalance(amount)
}
func (s *stateObject) setBalance(amount *uint256.Int) {
s.data.Balance = amount
}
func (s *stateObject) deepCopy(db *StateDB) *stateObject {
obj := &stateObject{
db: db,
address: s.address,
addrHash: s.addrHash,
origin: s.origin,
data: s.data,
code: s.code,
originStorage: s.originStorage.Copy(),
pendingStorage: s.pendingStorage.Copy(),
dirtyStorage: s.dirtyStorage.Copy(),
uncommittedStorage: s.uncommittedStorage.Copy(),
dirtyCode: s.dirtyCode,
selfDestructed: s.selfDestructed,
newContract: s.newContract,
}
if s.trie != nil {
obj.trie = db.db.CopyTrie(s.trie)
}
return obj
}
//
// Attribute accessors
//
// Address returns the address of the contract/account
func (s *stateObject) Address() common.Address {
return s.address
}
// Code returns the contract code associated with this object, if any.
func (s *stateObject) Code() []byte {
if len(s.code) != 0 {
return s.code
}
if bytes.Equal(s.CodeHash(), types.EmptyCodeHash.Bytes()) {
return nil
}
code, err := s.db.db.ContractCode(s.address, common.BytesToHash(s.CodeHash()))
if err != nil {
s.db.setError(fmt.Errorf("can't load code hash %x: %v", s.CodeHash(), err))
}
s.code = code
return code
}
// CodeSize returns the size of the contract code associated with this object,
// or zero if none. This method is an almost mirror of Code, but uses a cache
// inside the database to avoid loading codes seen recently.
func (s *stateObject) CodeSize() int {
if len(s.code) != 0 {
return len(s.code)
}
if bytes.Equal(s.CodeHash(), types.EmptyCodeHash.Bytes()) {
return 0
}
size, err := s.db.db.ContractCodeSize(s.address, common.BytesToHash(s.CodeHash()))
if err != nil {
s.db.setError(fmt.Errorf("can't load code size %x: %v", s.CodeHash(), err))
}
return size
}
func (s *stateObject) SetCode(codeHash common.Hash, code []byte) {
prevcode := s.Code()
s.db.journal.append(codeChange{
account: &s.address,
prevhash: s.CodeHash(),
prevcode: prevcode,
})
if s.db.logger != nil && s.db.logger.OnCodeChange != nil {
s.db.logger.OnCodeChange(s.address, common.BytesToHash(s.CodeHash()), prevcode, codeHash, code)
}
s.setCode(codeHash, code)
}
func (s *stateObject) setCode(codeHash common.Hash, code []byte) {
s.code = code
s.data.CodeHash = codeHash[:]
s.dirtyCode = true
}
func (s *stateObject) SetNonce(nonce uint64) {
s.db.journal.append(nonceChange{
account: &s.address,
prev: s.data.Nonce,
})
if s.db.logger != nil && s.db.logger.OnNonceChange != nil {
s.db.logger.OnNonceChange(s.address, s.data.Nonce, nonce)
}
s.setNonce(nonce)
}
func (s *stateObject) setNonce(nonce uint64) {
s.data.Nonce = nonce
}
func (s *stateObject) CodeHash() []byte {
return s.data.CodeHash
}
func (s *stateObject) Balance() *uint256.Int {
return s.data.Balance
}
func (s *stateObject) Nonce() uint64 {
return s.data.Nonce
}
func (s *stateObject) Root() common.Hash {
return s.data.Root
}