// 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
import (
"bytes"
"fmt"
"io"
"math/big"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/rlp"
"github.com/ethereum/go-ethereum/trie"
)
var emptyCodeHash = crypto.Keccak256(nil)
type Code []byte
func (self Code) String() string {
return string(self) //strings.Join(Disassemble(self), " ")
}
type Storage map[common.Hash]common.Hash
func (self Storage) String() (str string) {
for key, value := range self {
str += fmt.Sprintf("%X : %X\n", key, value)
}
return
}
func (self Storage) Copy() Storage {
cpy := make(Storage)
for key, value := range self {
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 can be accessed and modified through the object.
// Finally, call CommitTrie to write the modified storage trie into a database.
type stateObject struct {
address common.Address // Ethereum address of this account
data Account
db *StateDB
// 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
// Write caches.
trie *trie.SecureTrie // storage trie, which becomes non-nil on first access
code Code // contract bytecode, which gets set when code is loaded
cachedStorage Storage // Storage entry cache to avoid duplicate reads
dirtyStorage 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
touched bool
deleted bool
onDirty func(addr common.Address) // Callback method to mark a state object newly dirty
}
// empty returns whether the account is considered empty.
func (s *stateObject) empty() bool {
return s.data.Nonce == 0 && s.data.Balance.BitLen() == 0 && bytes.Equal(s.data.CodeHash, emptyCodeHash)
}
// Account is the Ethereum consensus representation of accounts.
// These objects are stored in the main account trie.
type Account struct {
Nonce uint64
Balance *big.Int
Root common.Hash // merkle root of the storage trie
CodeHash []byte
}
// newObject creates a state object.
func newObject(db *StateDB, address common.Address, data Account, onDirty func(addr common.Address)) *stateObject {
if data.Balance == nil {
data.Balance = new(big.Int)
}
if data.CodeHash == nil {
data.CodeHash = emptyCodeHash
}
return &stateObject{db: db, address: address, data: data, cachedStorage: make(Storage), dirtyStorage: make(Storage), onDirty: onDirty}
}
// EncodeRLP implements rlp.Encoder.
func (c *stateObject) EncodeRLP(w io.Writer) error {
return rlp.Encode(w, c.data)
}
// setError remembers the first non-nil error it is called with.
func (self *stateObject) setError(err error) {
if self.dbErr == nil {
self.dbErr = err
}
}
func (self *stateObject) markSuicided() {
self.suicided = true
if self.onDirty != nil {
self.onDirty(self.Address())
self.onDirty = nil
}
}
func (c *stateObject) touch() {
c.db.journal = append(c.db.journal, touchChange{
account: &c.address,
prev: c.touched,
})
if c.onDirty != nil {
c.onDirty(c.Address())
c.onDirty = nil
}
c.touched = true
}
func (c *stateObject) getTrie(db trie.Database) *trie.SecureTrie {
if c.trie == nil {
var err error
c.trie, err = trie.NewSecure(c.data.Root, db, 0)
if err != nil {
c.trie, _ = trie.NewSecure(common.Hash{}, db, 0)
c.setError(fmt.Errorf("can't create storage trie: %v", err))
}
}
return c.trie
}
// GetState returns a value in account storage.
func (self *stateObject) GetState(db trie.Database, key common.Hash) common.Hash {
value, exists := self.cachedStorage[key]
if exists {
return value
}
// Load from DB in case it is missing.
if enc := self.getTrie(db).Get(key[:]); len(enc) > 0 {
_, content, _, err := rlp.Split(enc)
if err != nil {
self.setError(err)
}
value.SetBytes(content)
}
if (value != common.Hash{}) {
self.cachedStorage[key] = value
}
return value
}
// SetState updates a value in account storage.
func (self *stateObject) SetState(db trie.Database, key, value common.Hash) {
self.db.journal = append(self.db.journal, storageChange{
account: &self.address,
key: key,
prevalue: self.GetState(db, key),
})
self.setState(key, value)
}
func (self *stateObject) setState(key, value common.Hash) {
self.cachedStorage[key] = value
self.dirtyStorage[key] = value
if self.onDirty != nil {
self.onDirty(self.Address())
self.onDirty = nil
}
}
// updateTrie writes cached storage modifications into the object's storage trie.
func (self *stateObject) updateTrie(db trie.Database) {
tr := self.getTrie(db)
for key, value := range self.dirtyStorage {
delete(self.dirtyStorage, key)
if (value == common.Hash{}) {
tr.Delete(key[:])
continue
}
// Encoding []byte cannot fail, ok to ignore the error.
v, _ := rlp.EncodeToBytes(bytes.TrimLeft(value[:], "\x00"))
tr.Update(key[:], v)
}
}
// UpdateRoot sets the trie root to the current root hash of
func (self *stateObject) updateRoot(db trie.Database) {
self.updateTrie(db)
self.data.Root = self.trie.Hash()
}
// CommitTrie the storage trie of the object to dwb.
// This updates the trie root.
func (self *stateObject) CommitTrie(db trie.Database, dbw trie.DatabaseWriter) error {
self.updateTrie(db)
if self.dbErr != nil {
return self.dbErr
}
root, err := self.trie.CommitTo(dbw)
if err == nil {
self.data.Root = root
}
return err
}
// AddBalance removes amount from c's balance.
// It is used to add funds to the destination account of a transfer.
func (c *stateObject) AddBalance(amount *big.Int) {
// EIP158: We must check emptiness for the objects such that the account
// clearing (0,0,0 objects) can take effect.
if amount.Cmp(common.Big0) == 0 {
if c.empty() {
c.touch()
}
return
}
c.SetBalance(new(big.Int).Add(c.Balance(), amount))
}
// SubBalance removes amount from c's balance.
// It is used to remove funds from the origin account of a transfer.
func (c *stateObject) SubBalance(amount *big.Int) {
if amount.Cmp(common.Big0) == 0 {
return
}
c.SetBalance(new(big.Int).Sub(c.Balance(), amount))
}
func (self *stateObject) SetBalance(amount *big.Int) {
self.db.journal = append(self.db.journal, balanceChange{
account: &self.address,
prev: new(big.Int).Set(self.data.Balance),
})
self.setBalance(amount)
}
func (self *stateObject) setBalance(amount *big.Int) {
self.data.Balance = amount
if self.onDirty != nil {
self.onDirty(self.Address())
self.onDirty = nil
}
}
// Return the gas back to the origin. Used by the Virtual machine or Closures
func (c *stateObject) ReturnGas(gas *big.Int) {}
func (self *stateObject) deepCopy(db *StateDB, onDirty func(addr common.Address)) *stateObject {
stateObject := newObject(db, self.address, self.data, onDirty)
stateObject.trie = self.trie
stateObject.code = self.code
stateObject.dirtyStorage = self.dirtyStorage.Copy()
stateObject.cachedStorage = self.dirtyStorage.Copy()
stateObject.suicided = self.suicided
stateObject.dirtyCode = self.dirtyCode
stateObject.deleted = self.deleted
return stateObject
}
//
// Attribute accessors
//
// Returns the address of the contract/account
func (c *stateObject) Address() common.Address {
return c.address
}
// Code returns the contract code associated with this object, if any.
func (self *stateObject) Code(db trie.Database) []byte {
if self.code != nil {
return self.code
}
if bytes.Equal(self.CodeHash(), emptyCodeHash) {
return nil
}
code, err := db.Get(self.CodeHash())
if err != nil {
self.setError(fmt.Errorf("can't load code hash %x: %v", self.CodeHash(), err))
}
self.code = code
return code
}
func (self *stateObject) SetCode(codeHash common.Hash, code []byte) {
prevcode := self.Code(self.db.db)
self.db.journal = append(self.db.journal, codeChange{
account: &self.address,
prevhash: self.CodeHash(),
prevcode: prevcode,
})
self.setCode(codeHash, code)
}
func (self *stateObject) setCode(codeHash common.Hash, code []byte) {
self.code = code
self.data.CodeHash = codeHash[:]
self.dirtyCode = true
if self.onDirty != nil {
self.onDirty(self.Address())
self.onDirty = nil
}
}
func (self *stateObject) SetNonce(nonce uint64) {
self.db.journal = append(self.db.journal, nonceChange{
account: &self.address,
prev: self.data.Nonce,
})
self.setNonce(nonce)
}
func (self *stateObject) setNonce(nonce uint64) {
self.data.Nonce = nonce
if self.onDirty != nil {
self.onDirty(self.Address())
self.onDirty = nil
}
}
func (self *stateObject) CodeHash() []byte {
return self.data.CodeHash
}
func (self *stateObject) Balance() *big.Int {
return self.data.Balance
}
func (self *stateObject) Nonce() uint64 {
return self.data.Nonce
}
// Never called, but must be present to allow stateObject to be used
// as a vm.Account interface that also satisfies the vm.ContractRef
// interface. Interfaces are awesome.
func (self *stateObject) Value() *big.Int {
panic("Value on stateObject should never be called")
}
