// Copyright 2015 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 light
import (
"bytes"
"fmt"
"math/big"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
"github.com/ethereum/go-ethereum/rlp"
"golang.org/x/net/context"
)
var emptyCodeHash = crypto.Keccak256(nil)
// Code represents a contract code in binary form
type Code []byte
// String returns a string representation of the code
func (self Code) String() string {
return string(self) //strings.Join(Disassemble(self), " ")
}
// Storage is a memory map cache of a contract storage
type Storage map[common.Hash]common.Hash
// String returns a string representation of the storage cache
func (self Storage) String() (str string) {
for key, value := range self {
str += fmt.Sprintf("%X : %X\n", key, value)
}
return
}
// Copy copies the contents of a storage cache
func (self Storage) Copy() Storage {
cpy := make(Storage)
for key, value := range self {
cpy[key] = value
}
return cpy
}
// StateObject is a memory representation of an account or contract and its storage.
// This version is ODR capable, caching only the already accessed part of the
// storage, retrieving unknown parts on-demand from the ODR backend. Changes are
// never stored in the local database, only in the memory objects.
type StateObject struct {
odr OdrBackend
trie *LightTrie
// Address belonging to this account
address common.Address
// The balance of the account
balance *big.Int
// The nonce of the account
nonce uint64
// The code hash if code is present (i.e. a contract)
codeHash []byte
// The code for this account
code Code
// Cached storage (flushed when updated)
storage Storage
// Mark for deletion
// When an object is marked for deletion it will be delete from the trie
// during the "update" phase of the state transition
remove bool
deleted bool
dirty bool
}
// NewStateObject creates a new StateObject of the specified account address
func NewStateObject(address common.Address, odr OdrBackend) *StateObject {
object := &StateObject{
odr: odr,
address: address,
balance: new(big.Int),
dirty: true,
codeHash: emptyCodeHash,
storage: make(Storage),
}
object.trie = NewLightTrie(&TrieID{}, odr, true)
return object
}
// MarkForDeletion marks an account to be removed
func (self *StateObject) MarkForDeletion() {
self.remove = true
self.dirty = true
if glog.V(logger.Core) {
glog.Infof("%x: #%d %v X\n", self.Address(), self.nonce, self.balance)
}
}
// getAddr gets the storage value at the given address from the trie
func (c *StateObject) getAddr(ctx context.Context, addr common.Hash) (common.Hash, error) {
var ret []byte
val, err := c.trie.Get(ctx, addr[:])
if err != nil {
return common.Hash{}, err
}
rlp.DecodeBytes(val, &ret)
return common.BytesToHash(ret), nil
}
// Storage returns the storage cache object of the account
func (self *StateObject) Storage() Storage {
return self.storage
}
// GetState returns the storage value at the given address from either the cache
// or the trie
func (self *StateObject) GetState(ctx context.Context, key common.Hash) (common.Hash, error) {
value, exists := self.storage[key]
if !exists {
var err error
value, err = self.getAddr(ctx, key)
if err != nil {
return common.Hash{}, err
}
if (value != common.Hash{}) {
self.storage[key] = value
}
}
return value, nil
}
// SetState sets the storage value at the given address
func (self *StateObject) SetState(k, value common.Hash) {
self.storage[k] = value
self.dirty = true
}
// AddBalance adds the given amount to the account balance
func (c *StateObject) AddBalance(amount *big.Int) {
c.SetBalance(new(big.Int).Add(c.balance, amount))
if glog.V(logger.Core) {
glog.Infof("%x: #%d %v (+ %v)\n", c.Address(), c.nonce, c.balance, amount)
}
}
// SubBalance subtracts the given amount from the account balance
func (c *StateObject) SubBalance(amount *big.Int) {
c.SetBalance(new(big.Int).Sub(c.balance, amount))
if glog.V(logger.Core) {
glog.Infof("%x: #%d %v (- %v)\n", c.Address(), c.nonce, c.balance, amount)
}
}
// SetBalance sets the account balance to the given amount
func (c *StateObject) SetBalance(amount *big.Int) {
c.balance = amount
c.dirty = true
}
// ReturnGas returns the gas back to the origin. Used by the Virtual machine or Closures
func (c *StateObject) ReturnGas(gas *big.Int) {}
// Copy creates a copy of the state object
func (self *StateObject) Copy() *StateObject {
stateObject := NewStateObject(self.Address(), self.odr)
stateObject.balance.Set(self.balance)
stateObject.codeHash = common.CopyBytes(self.codeHash)
stateObject.nonce = self.nonce
stateObject.trie = self.trie
stateObject.code = self.code
stateObject.storage = self.storage.Copy()
stateObject.remove = self.remove
stateObject.dirty = self.dirty
stateObject.deleted = self.deleted
return stateObject
}
//
// Attribute accessors
//
// empty returns whether the account is considered empty.
func (self *StateObject) empty() bool {
return self.nonce == 0 && self.balance.BitLen() == 0 && bytes.Equal(self.codeHash, emptyCodeHash)
}
// Balance returns the account balance
func (self *StateObject) Balance() *big.Int {
return self.balance
}
// Address returns the address of the contract/account
func (self *StateObject) Address() common.Address {
return self.address
}
// Code returns the contract code
func (self *StateObject) Code() []byte {
return self.code
}
// SetCode sets the contract code
func (self *StateObject) SetCode(hash common.Hash, code []byte) {
self.code = code
self.codeHash = hash[:]
self.dirty = true
}
// SetNonce sets the account nonce
func (self *StateObject) SetNonce(nonce uint64) {
self.nonce = nonce
self.dirty = true
}
// Nonce returns the account nonce
func (self *StateObject) Nonce() uint64 {
return self.nonce
}
// ForEachStorage calls a callback function for every key/value pair found
// in the local storage cache. Note that unlike core/state.StateObject,
// light.StateObject only returns cached values and doesn't download the
// entire storage tree.
func (self *StateObject) ForEachStorage(cb func(key, value common.Hash) bool) {
for h, v := range self.storage {
cb(h, v)
}
}
// 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")
}
// Encoding
type extStateObject struct {
Nonce uint64
Balance *big.Int
Root common.Hash
CodeHash []byte
}
// DecodeObject decodes an RLP-encoded state object.
func DecodeObject(ctx context.Context, stateID *TrieID, address common.Address, odr OdrBackend, data []byte) (*StateObject, error) {
var (
obj = &StateObject{address: address, odr: odr, storage: make(Storage)}
ext extStateObject
err error
)
if err = rlp.DecodeBytes(data, &ext); err != nil {
return nil, err
}
trieID := StorageTrieID(stateID, address, ext.Root)
obj.trie = NewLightTrie(trieID, odr, true)
if !bytes.Equal(ext.CodeHash, emptyCodeHash) {
if obj.code, err = retrieveContractCode(ctx, obj.odr, trieID, common.BytesToHash(ext.CodeHash)); err != nil {
return nil, fmt.Errorf("can't find code for hash %x: %v", ext.CodeHash, err)
}
}
obj.nonce = ext.Nonce
obj.balance = ext.Balance
obj.codeHash = ext.CodeHash
return obj, nil
}
