// 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 (
"fmt"
"math/big"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/vm"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
"github.com/ethereum/go-ethereum/rlp"
"github.com/ethereum/go-ethereum/trie"
)
// The starting nonce determines the default nonce when new accounts are being
// created.
var StartingNonce uint64
// 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 ethdb.Database
trie *trie.SecureTrie
// This map caches canon state accounts.
all map[common.Address]Account
// This map holds 'live' objects, which will get modified while processing a state transition.
stateObjects map[common.Address]*StateObject
stateObjectsDirty map[common.Address]struct{}
// The refund counter, also used by state transitioning.
refund *big.Int
thash, bhash common.Hash
txIndex int
logs map[common.Hash]vm.Logs
logSize uint
}
// Create a new state from a given trie
func New(root common.Hash, db ethdb.Database) (*StateDB, error) {
tr, err := trie.NewSecure(root, db)
if err != nil {
return nil, err
}
return &StateDB{
db: db,
trie: tr,
all: make(map[common.Address]Account),
stateObjects: make(map[common.Address]*StateObject),
stateObjectsDirty: make(map[common.Address]struct{}),
refund: new(big.Int),
logs: make(map[common.Hash]vm.Logs),
}, nil
}
// Reset clears out all emphemeral state objects from the state db, but keeps
// the underlying state trie to avoid reloading data for the next operations.
func (self *StateDB) Reset(root common.Hash) error {
tr, err := trie.NewSecure(root, self.db)
if err != nil {
return err
}
all := self.all
if self.trie.Hash() != root {
// The root has changed, invalidate canon state.
all = make(map[common.Address]Account)
}
*self = StateDB{
db: self.db,
trie: tr,
all: all,
stateObjects: make(map[common.Address]*StateObject),
stateObjectsDirty: make(map[common.Address]struct{}),
refund: new(big.Int),
logs: make(map[common.Hash]vm.Logs),
}
return nil
}
func (self *StateDB) StartRecord(thash, bhash common.Hash, ti int) {
self.thash = thash
self.bhash = bhash
self.txIndex = ti
}
func (self *StateDB) AddLog(log *vm.Log) {
log.TxHash = self.thash
log.BlockHash = self.bhash
log.TxIndex = uint(self.txIndex)
log.Index = self.logSize
self.logs[self.thash] = append(self.logs[self.thash], log)
self.logSize++
}
func (self *StateDB) GetLogs(hash common.Hash) vm.Logs {
return self.logs[hash]
}
func (self *StateDB) Logs() vm.Logs {
var logs vm.Logs
for _, lgs := range self.logs {
logs = append(logs, lgs...)
}
return logs
}
func (self *StateDB) AddRefund(gas *big.Int) {
self.refund.Add(self.refund, gas)
}
func (self *StateDB) HasAccount(addr common.Address) bool {
return self.GetStateObject(addr) != nil
}
func (self *StateDB) Exist(addr common.Address) bool {
return self.GetStateObject(addr) != nil
}
func (self *StateDB) GetAccount(addr common.Address) vm.Account {
return self.GetStateObject(addr)
}
// Retrieve the balance from the given address or 0 if object not found
func (self *StateDB) GetBalance(addr common.Address) *big.Int {
stateObject := self.GetStateObject(addr)
if stateObject != nil {
return stateObject.Balance()
}
return common.Big0
}
func (self *StateDB) GetNonce(addr common.Address) uint64 {
stateObject := self.GetStateObject(addr)
if stateObject != nil {
return stateObject.Nonce()
}
return StartingNonce
}
func (self *StateDB) GetCode(addr common.Address) []byte {
stateObject := self.GetStateObject(addr)
if stateObject != nil {
return stateObject.Code(self.db)
}
return nil
}
func (self *StateDB) GetCodeSize(addr common.Address) int {
stateObject := self.GetStateObject(addr)
if stateObject != nil {
return stateObject.CodeSize(self.db)
}
return 0
}
func (self *StateDB) GetState(a common.Address, b common.Hash) common.Hash {
stateObject := self.GetStateObject(a)
if stateObject != nil {
return stateObject.GetState(self.db, b)
}
return common.Hash{}
}
func (self *StateDB) IsDeleted(addr common.Address) bool {
stateObject := self.GetStateObject(addr)
if stateObject != nil {
return stateObject.remove
}
return false
}
/*
* SETTERS
*/
func (self *StateDB) AddBalance(addr common.Address, amount *big.Int) {
stateObject := self.GetOrNewStateObject(addr)
if stateObject != nil {
stateObject.AddBalance(amount)
}
}
func (self *StateDB) SetNonce(addr common.Address, nonce uint64) {
stateObject := self.GetOrNewStateObject(addr)
if stateObject != nil {
stateObject.SetNonce(nonce)
}
}
func (self *StateDB) SetCode(addr common.Address, code []byte) {
stateObject := self.GetOrNewStateObject(addr)
if stateObject != nil {
stateObject.SetCode(code)
}
}
func (self *StateDB) SetState(addr common.Address, key common.Hash, value common.Hash) {
stateObject := self.GetOrNewStateObject(addr)
if stateObject != nil {
stateObject.SetState(key, value)
}
}
func (self *StateDB) Delete(addr common.Address) bool {
stateObject := self.GetStateObject(addr)
if stateObject != nil {
stateObject.MarkForDeletion()
stateObject.data.Balance = new(big.Int)
return true
}
return false
}
//
// Setting, updating & deleting state object methods
//
// Update the given state object and apply it to state trie
func (self *StateDB) UpdateStateObject(stateObject *StateObject) {
addr := stateObject.Address()
data, err := rlp.EncodeToBytes(stateObject)
if err != nil {
panic(fmt.Errorf("can't encode object at %x: %v", addr[:], err))
}
self.trie.Update(addr[:], data)
}
// Delete the given state object and delete it from the state trie
func (self *StateDB) DeleteStateObject(stateObject *StateObject) {
stateObject.deleted = true
addr := stateObject.Address()
self.trie.Delete(addr[:])
}
// Retrieve a state object given my the address. Returns nil if not found.
func (self *StateDB) GetStateObject(addr common.Address) (stateObject *StateObject) {
// Prefer 'live' objects.
if obj := self.stateObjects[addr]; obj != nil {
if obj.deleted {
return nil
}
return obj
}
// Use cached account data from the canon state if possible.
if data, ok := self.all[addr]; ok {
obj := NewObject(addr, data, self.MarkStateObjectDirty)
self.SetStateObject(obj)
return obj
}
// Load the object from the database.
enc := self.trie.Get(addr[:])
if len(enc) == 0 {
return nil
}
var data Account
if err := rlp.DecodeBytes(enc, &data); err != nil {
glog.Errorf("can't decode object at %x: %v", addr[:], err)
return nil
}
// Update the all cache. Content in DB always corresponds
// to the current head state so this is ok to do here.
// The object we just loaded has no storage trie and code yet.
self.all[addr] = data
// Insert into the live set.
obj := NewObject(addr, data, self.MarkStateObjectDirty)
self.SetStateObject(obj)
return obj
}
func (self *StateDB) SetStateObject(object *StateObject) {
self.stateObjects[object.Address()] = object
}
// Retrieve a state object or create a new state object if nil
func (self *StateDB) GetOrNewStateObject(addr common.Address) *StateObject {
stateObject := self.GetStateObject(addr)
if stateObject == nil || stateObject.deleted {
stateObject = self.CreateStateObject(addr)
}
return stateObject
}
// NewStateObject create a state object whether it exist in the trie or not
func (self *StateDB) newStateObject(addr common.Address) *StateObject {
if glog.V(logger.Core) {
glog.Infof("(+) %x\n", addr)
}
obj := NewObject(addr, Account{}, self.MarkStateObjectDirty)
obj.SetNonce(StartingNonce) // sets the object to dirty
self.stateObjects[addr] = obj
return obj
}
// MarkStateObjectDirty adds the specified object to the dirty map to avoid costly
// state object cache iteration to find a handful of modified ones.
func (self *StateDB) MarkStateObjectDirty(addr common.Address) {
self.stateObjectsDirty[addr] = struct{}{}
}
// Creates creates a new state object and takes ownership.
func (self *StateDB) CreateStateObject(addr common.Address) *StateObject {
// Get previous (if any)
so := self.GetStateObject(addr)
// Create a new one
newSo := self.newStateObject(addr)
// If it existed set the balance to the new account
if so != nil {
newSo.data.Balance = so.data.Balance
}
return newSo
}
func (self *StateDB) CreateAccount(addr common.Address) vm.Account {
return self.CreateStateObject(addr)
}
//
// Setting, copying of the state methods
//
func (self *StateDB) Copy() *StateDB {
// Copy all the basic fields, initialize the memory ones
state := &StateDB{
db: self.db,
trie: self.trie,
all: self.all,
stateObjects: make(map[common.Address]*StateObject, len(self.stateObjectsDirty)),
stateObjectsDirty: make(map[common.Address]struct{}, len(self.stateObjectsDirty)),
refund: new(big.Int).Set(self.refund),
logs: make(map[common.Hash]vm.Logs, len(self.logs)),
logSize: self.logSize,
}
// Copy the dirty states and logs
for addr, _ := range self.stateObjectsDirty {
state.stateObjects[addr] = self.stateObjects[addr].Copy(self.db, state.MarkStateObjectDirty)
state.stateObjectsDirty[addr] = struct{}{}
}
for hash, logs := range self.logs {
state.logs[hash] = make(vm.Logs, len(logs))
copy(state.logs[hash], logs)
}
return state
}
func (self *StateDB) Set(state *StateDB) {
self.trie = state.trie
self.stateObjects = state.stateObjects
self.stateObjectsDirty = state.stateObjectsDirty
self.all = state.all
self.refund = state.refund
self.logs = state.logs
self.logSize = state.logSize
}
func (self *StateDB) GetRefund() *big.Int {
return self.refund
}
// 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() common.Hash {
s.refund = new(big.Int)
for addr, _ := range s.stateObjectsDirty {
stateObject := s.stateObjects[addr]
if stateObject.remove {
s.DeleteStateObject(stateObject)
} else {
stateObject.UpdateRoot(s.db)
s.UpdateStateObject(stateObject)
}
}
return s.trie.Hash()
}
// DeleteSuicides flags the suicided objects for deletion so that it
// won't be referenced again when called / queried up on.
//
// DeleteSuicides should not be used for consensus related updates
// under any circumstances.
func (s *StateDB) DeleteSuicides() {
// Reset refund so that any used-gas calculations can use
// this method.
s.refund = new(big.Int)
for addr, _ := range s.stateObjectsDirty {
stateObject := s.stateObjects[addr]
// If the object has been removed by a suicide
// flag the object as deleted.
if stateObject.remove {
stateObject.deleted = true
}
delete(s.stateObjectsDirty, addr)
}
}
// Commit commits all state changes to the database.
func (s *StateDB) Commit() (root common.Hash, err error) {
root, batch := s.CommitBatch()
return root, batch.Write()
}
// CommitBatch commits all state changes to a write batch but does not
// execute the batch. It is used to validate state changes against
// the root hash stored in a block.
func (s *StateDB) CommitBatch() (root common.Hash, batch ethdb.Batch) {
batch = s.db.NewBatch()
root, _ = s.commit(batch)
return root, batch
}
func (s *StateDB) commit(dbw trie.DatabaseWriter) (root common.Hash, err error) {
s.refund = new(big.Int)
defer func() {
if err != nil {
// Committing failed, any updates to the canon state are invalid.
s.all = make(map[common.Address]Account)
}
}()
// Commit objects to the trie.
for addr, stateObject := range s.stateObjects {
if stateObject.remove {
// If the object has been removed, don't bother syncing it
// and just mark it for deletion in the trie.
s.DeleteStateObject(stateObject)
delete(s.all, addr)
} else if _, ok := s.stateObjectsDirty[addr]; ok {
// Write any contract code associated with the state object
if stateObject.code != nil && stateObject.dirtyCode {
if err := dbw.Put(stateObject.CodeHash(), stateObject.code); err != nil {
return common.Hash{}, err
}
stateObject.dirtyCode = false
}
// Write any storage changes in the state object to its storage trie.
if err := stateObject.CommitTrie(s.db, dbw); err != nil {
return common.Hash{}, err
}
// Update the object in the main account trie.
s.UpdateStateObject(stateObject)
s.all[addr] = stateObject.data
}
delete(s.stateObjectsDirty, addr)
}
// Write trie changes.
return s.trie.CommitTo(dbw)
}
func (self *StateDB) Refunds() *big.Int {
return self.refund
}