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"
"io"
"math/big"
"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/metrics"
"github.com/ethereum/go-ethereum/rlp"
"github.com/ethereum/go-ethereum/trie/trienode"
)
type Code []byte
func (c Code) String() string {
return string(c) //strings.Join(Disassemble(c), " ")
}
type Storage map[common.Hash]common.Hash
func (s Storage) String() (str string) {
for key, value := range s {
str += fmt.Sprintf("%X : %X\n", key, value)
}
return
}
func (s Storage) Copy() Storage {
cpy := make(Storage, len(s))
for key, value := range s {
cpy[key] = value
}
return cpy
}
// 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 Code // contract bytecode, which gets set when code is loaded
originStorage Storage // Storage cache of original entries to dedup rewrites
pendingStorage Storage // Storage entries that need to be flushed to disk, at the end of an entire block
dirtyStorage Storage // Storage entries that have been modified in the current transaction execution, reset for every transaction
// 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
// Flag whether the account was marked as deleted. A self-destructed account
// or an account that is considered as empty will be marked as deleted at
// the end of transaction and no longer accessible anymore.
deleted bool
// Flag whether the object was created in the current transaction
created bool
}
// empty returns whether the account is considered empty.
func (s *stateObject) empty() bool {
return s.data.Nonce == 0 && s.data.Balance.Sign() == 0 && 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),
pendingStorage: make(Storage),
dirtyStorage: make(Storage),
}
}
// EncodeRLP implements rlp.Encoder.
func (s *stateObject) EncodeRLP(w io.Writer) error {
return rlp.Encode(w, &s.data)
}
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.
func (s *stateObject) getTrie() (Trie, error) {
if s.trie == nil {
// Try fetching from prefetcher first
if s.data.Root != types.EmptyRootHash && s.db.prefetcher != nil {
// When the miner is creating the pending state, there is no prefetcher
s.trie = s.db.prefetcher.trie(s.addrHash, s.data.Root)
}
if s.trie == nil {
tr, err := s.db.db.OpenStorageTrie(s.db.originalRoot, s.address, s.data.Root)
if err != nil {
return nil, err
}
s.trie = tr
}
}
return s.trie, nil
}
// GetState retrieves a value from the account storage trie.
func (s *stateObject) GetState(key common.Hash) common.Hash {
// If we have a dirty value for this state entry, return it
value, dirty := s.dirtyStorage[key]
if dirty {
return value
}
// Otherwise return the entry's original value
return s.GetCommittedState(key)
}
// GetCommittedState retrieves a value from the committed account storage trie.
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 {
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()))
if metrics.EnabledExpensive {
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())
if metrics.EnabledExpensive {
s.db.StorageReads += time.Since(start)
}
if err != nil {
s.db.setError(err)
return common.Hash{}
}
value.SetBytes(val)
}
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
prev := 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,
prevalue: prev,
})
s.setState(key, value)
}
func (s *stateObject) setState(key, value common.Hash) {
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(prefetch bool) {
slotsToPrefetch := make([][]byte, 0, len(s.dirtyStorage))
for key, value := range s.dirtyStorage {
s.pendingStorage[key] = value
if value != s.originStorage[key] {
slotsToPrefetch = append(slotsToPrefetch, common.CopyBytes(key[:])) // Copy needed for closure
}
}
if s.db.prefetcher != nil && prefetch && len(slotsToPrefetch) > 0 && s.data.Root != types.EmptyRootHash {
s.db.prefetcher.prefetch(s.addrHash, s.data.Root, s.address, slotsToPrefetch)
}
if len(s.dirtyStorage) > 0 {
s.dirtyStorage = make(Storage)
}
}
// updateTrie writes cached storage modifications into the object's storage trie.
// It will return nil if the trie has not been loaded and no changes have been
// made. An error will be returned if the trie can't be loaded/updated correctly.
func (s *stateObject) updateTrie() (Trie, error) {
// Make sure all dirty slots are finalized into the pending storage area
s.finalise(false) // Don't prefetch anymore, pull directly if need be
if len(s.pendingStorage) == 0 {
return s.trie, nil
}
// Track the amount of time wasted on updating the storage trie
if metrics.EnabledExpensive {
defer func(start time.Time) { s.db.StorageUpdates += time.Since(start) }(time.Now())
}
// The snapshot storage map for the object
var (
storage map[common.Hash][]byte
origin map[common.Hash][]byte
hasher = s.db.hasher
)
tr, err := s.getTrie()
if err != nil {
s.db.setError(err)
return nil, err
}
// Insert all the pending updates into the trie
usedStorage := make([][]byte, 0, len(s.pendingStorage))
for key, value := range s.pendingStorage {
// Skip noop changes, persist actual changes
if value == s.originStorage[key] {
continue
}
prev := s.originStorage[key]
s.originStorage[key] = value
// rlp-encoded value to be used by the snapshot
var snapshotVal []byte
if (value == common.Hash{}) {
if err := tr.DeleteStorage(s.address, key[:]); err != nil {
s.db.setError(err)
return nil, err
}
s.db.StorageDeleted += 1
} else {
trimmedVal := common.TrimLeftZeroes(value[:])
// Encoding []byte cannot fail, ok to ignore the error.
snapshotVal, _ = rlp.EncodeToBytes(trimmedVal)
if err := tr.UpdateStorage(s.address, key[:], trimmedVal); err != nil {
s.db.setError(err)
return nil, err
}
s.db.StorageUpdated += 1
}
// Cache the mutated storage slots until commit
if storage == nil {
if storage = s.db.storages[s.addrHash]; storage == nil {
storage = make(map[common.Hash][]byte)
s.db.storages[s.addrHash] = storage
}
}
khash := crypto.HashData(hasher, key[:])
storage[khash] = snapshotVal // snapshotVal will be nil if it's deleted
// Cache the original value of mutated storage slots
if origin == nil {
if origin = s.db.storagesOrigin[s.addrHash]; origin == nil {
origin = make(map[common.Hash][]byte)
s.db.storagesOrigin[s.addrHash] = origin
}
}
// Track the original value of slot only if it's mutated first time
if _, ok := origin[khash]; !ok {
if prev == (common.Hash{}) {
origin[khash] = nil // nil if it was not present previously
} else {
// Encoding []byte cannot fail, ok to ignore the error.
b, _ := rlp.EncodeToBytes(common.TrimLeftZeroes(prev[:]))
origin[khash] = b
}
}
// Cache the items for preloading
usedStorage = append(usedStorage, common.CopyBytes(key[:])) // Copy needed for closure
}
if s.db.prefetcher != nil {
s.db.prefetcher.used(s.addrHash, s.data.Root, usedStorage)
}
if len(s.pendingStorage) > 0 {
s.pendingStorage = make(Storage)
}
return tr, nil
}
// UpdateRoot sets the trie root to the current root hash of. An error
// will be returned if trie root hash is not computed correctly.
func (s *stateObject) updateRoot() {
tr, err := s.updateTrie()
if err != nil {
return
}
// If nothing changed, don't bother with hashing anything
if tr == nil {
return
}
// Track the amount of time wasted on hashing the storage trie
if metrics.EnabledExpensive {
defer func(start time.Time) { s.db.StorageHashes += time.Since(start) }(time.Now())
}
s.data.Root = tr.Hash()
}
// commit returns the changes made in storage trie and updates the account data.
func (s *stateObject) commit() (*trienode.NodeSet, error) {
tr, err := s.updateTrie()
if err != nil {
return nil, err
}
// If nothing changed, don't bother with committing anything
if tr == nil {
s.origin = s.data.Copy()
return nil, nil
}
// Track the amount of time wasted on committing the storage trie
if metrics.EnabledExpensive {
defer func(start time.Time) { s.db.StorageCommits += time.Since(start) }(time.Now())
}
root, nodes, err := tr.Commit(false)
if err != nil {
return nil, err
}
s.data.Root = root
// Update original account data after commit
s.origin = s.data.Copy()
return 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 *big.Int) {
// EIP161: We must check emptiness for the objects such that the account
// clearing (0,0,0 objects) can take effect.
if amount.Sign() == 0 {
if s.empty() {
s.touch()
}
return
}
s.SetBalance(new(big.Int).Add(s.Balance(), amount))
}
// 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 *big.Int) {
if amount.Sign() == 0 {
return
}
s.SetBalance(new(big.Int).Sub(s.Balance(), amount))
}
func (s *stateObject) SetBalance(amount *big.Int) {
s.db.journal.append(balanceChange{
account: &s.address,
prev: new(big.Int).Set(s.data.Balance),
})
s.setBalance(amount)
}
func (s *stateObject) setBalance(amount *big.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,
}
if s.trie != nil {
obj.trie = db.db.CopyTrie(s.trie)
}
obj.code = s.code
obj.dirtyStorage = s.dirtyStorage.Copy()
obj.originStorage = s.originStorage.Copy()
obj.pendingStorage = s.pendingStorage.Copy()
obj.selfDestructed = s.selfDestructed
obj.dirtyCode = s.dirtyCode
obj.deleted = s.deleted
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 s.code != nil {
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 s.code != nil {
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,
})
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,
})
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() *big.Int {
return s.data.Balance
}
func (s *stateObject) Nonce() uint64 {
return s.data.Nonce
}