go-ethereum/state/state.go

package state

import (
	"math/big"

	"github.com/ethereum/go-ethereum/ethutil"
	"github.com/ethereum/go-ethereum/logger"
	"github.com/ethereum/go-ethereum/trie"
)

var statelogger = logger.NewLogger("STATE")

// 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 {
	// The trie for this structure
	Trie *trie.Trie

	stateObjects map[string]*StateObject

	manifest *Manifest

	refund map[string][]refund

	logs Logs
}

// Create a new state from a given trie
func New(trie *trie.Trie) *StateDB {
	return &StateDB{Trie: trie, stateObjects: make(map[string]*StateObject), manifest: NewManifest(), refund: make(map[string][]refund)}
}

func (self *StateDB) EmptyLogs() {
	self.logs = nil
}

func (self *StateDB) AddLog(log *Log) {
	self.logs = append(self.logs, log)
}

func (self *StateDB) Logs() Logs {
	return self.logs
}

// Retrieve the balance from the given address or 0 if object not found
func (self *StateDB) GetBalance(addr []byte) *big.Int {
	stateObject := self.GetStateObject(addr)
	if stateObject != nil {
		return stateObject.balance
	}

	return ethutil.Big0
}

type refund struct {
	gas, price *big.Int
}

func (self *StateDB) Refund(addr []byte, gas, price *big.Int) {
	self.refund[string(addr)] = append(self.refund[string(addr)], refund{gas, price})
}

func (self *StateDB) AddBalance(addr []byte, amount *big.Int) {
	stateObject := self.GetStateObject(addr)
	if stateObject != nil {
		stateObject.AddBalance(amount)
	}
}

func (self *StateDB) GetNonce(addr []byte) uint64 {
	stateObject := self.GetStateObject(addr)
	if stateObject != nil {
		return stateObject.Nonce
	}

	return 0
}

func (self *StateDB) SetNonce(addr []byte, nonce uint64) {
	stateObject := self.GetStateObject(addr)
	if stateObject != nil {
		stateObject.Nonce = nonce
	}
}

func (self *StateDB) GetCode(addr []byte) []byte {
	stateObject := self.GetStateObject(addr)
	if stateObject != nil {
		return stateObject.Code
	}

	return nil
}

func (self *StateDB) GetState(a, b []byte) []byte {
	stateObject := self.GetStateObject(a)
	if stateObject != nil {
		return stateObject.GetState(b).Bytes()
	}

	return nil
}

func (self *StateDB) SetState(addr, key []byte, value interface{}) {
	stateObject := self.GetStateObject(addr)
	if stateObject != nil {
		stateObject.SetState(key, ethutil.NewValue(value))
	}
}

func (self *StateDB) Delete(addr []byte) bool {
	stateObject := self.GetStateObject(addr)
	if stateObject != nil {
		stateObject.MarkForDeletion()

		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()

	if len(stateObject.CodeHash()) > 0 {
		ethutil.Config.Db.Put(stateObject.CodeHash(), stateObject.Code)
	}

	self.Trie.Update(string(addr), string(stateObject.RlpEncode()))
}

// Delete the given state object and delete it from the state trie
func (self *StateDB) DeleteStateObject(stateObject *StateObject) {
	self.Trie.Delete(string(stateObject.Address()))

	delete(self.stateObjects, string(stateObject.Address()))
}

// Retrieve a state object given my the address. Nil if not found
func (self *StateDB) GetStateObject(addr []byte) *StateObject {
	addr = ethutil.Address(addr)

	stateObject := self.stateObjects[string(addr)]
	if stateObject != nil {
		return stateObject
	}

	data := self.Trie.Get(string(addr))
	if len(data) == 0 {
		return nil
	}

	stateObject = NewStateObjectFromBytes(addr, []byte(data))
	self.SetStateObject(stateObject)

	return stateObject
}

func (self *StateDB) SetStateObject(object *StateObject) {
	self.stateObjects[string(object.address)] = object
}

// Retrieve a state object or create a new state object if nil
func (self *StateDB) GetOrNewStateObject(addr []byte) *StateObject {
	stateObject := self.GetStateObject(addr)
	if stateObject == nil {
		stateObject = self.NewStateObject(addr)
	}

	return stateObject
}

// Create a state object whether it exist in the trie or not
func (self *StateDB) NewStateObject(addr []byte) *StateObject {
	addr = ethutil.Address(addr)

	statelogger.Debugf("(+) %x\n", addr)

	stateObject := NewStateObject(addr)
	self.stateObjects[string(addr)] = stateObject

	return stateObject
}

// Deprecated
func (self *StateDB) GetAccount(addr []byte) *StateObject {
	return self.GetOrNewStateObject(addr)
}

//
// Setting, copying of the state methods
//

func (s *StateDB) Cmp(other *StateDB) bool {
	return s.Trie.Cmp(other.Trie)
}

func (self *StateDB) Copy() *StateDB {
	if self.Trie != nil {
		state := New(self.Trie.Copy())
		for k, stateObject := range self.stateObjects {
			state.stateObjects[k] = stateObject.Copy()
		}

		for addr, refund := range self.refund {
			state.refund[addr] = refund
		}

		logs := make(Logs, len(self.logs))
		copy(logs, self.logs)
		state.logs = logs

		return state
	}

	return nil
}

func (self *StateDB) Set(state *StateDB) {
	if state == nil {
		panic("Tried setting 'state' to nil through 'Set'")
	}

	self.Trie = state.Trie
	self.stateObjects = state.stateObjects
	self.refund = state.refund
	self.logs = state.logs
}

func (s *StateDB) Root() []byte {
	return s.Trie.GetRoot()
}

// Resets the trie and all siblings
func (s *StateDB) Reset() {
	s.Trie.Undo()

	// Reset all nested states
	for _, stateObject := range s.stateObjects {
		if stateObject.State == nil {
			continue
		}

		stateObject.Reset()
	}

	s.Empty()
}

// Syncs the trie and all siblings
func (s *StateDB) Sync() {
	// Sync all nested states
	for _, stateObject := range s.stateObjects {
		if stateObject.State == nil {
			continue
		}

		stateObject.State.Sync()
	}

	s.Trie.Sync()

	s.Empty()
}

func (self *StateDB) Empty() {
	self.stateObjects = make(map[string]*StateObject)
	self.refund = make(map[string][]refund)
}

func (self *StateDB) Update(gasUsed *big.Int) {
	var deleted bool

	// Refund any gas that's left
	// XXX THIS WILL CHANGE IN POC8
	uhalf := new(big.Int).Div(gasUsed, ethutil.Big2)
	for addr, refs := range self.refund {
		for _, ref := range refs {
			refund := ethutil.BigMin(uhalf, ref.gas)

			self.GetStateObject([]byte(addr)).AddBalance(refund.Mul(refund, ref.price))
		}
	}
	self.refund = make(map[string][]refund)

	for _, stateObject := range self.stateObjects {
		if stateObject.remove {
			self.DeleteStateObject(stateObject)
			deleted = true
		} else {
			stateObject.Sync()

			self.UpdateStateObject(stateObject)
		}
	}

	// FIXME trie delete is broken
	if deleted {
		valid, t2 := trie.ParanoiaCheck(self.Trie)
		if !valid {
			statelogger.Infof("Warn: PARANOIA: Different state root during copy %x vs %x\n", self.Trie.GetRoot(), t2.GetRoot())

			self.Trie = t2
		}
	}
}

func (self *StateDB) Manifest() *Manifest {
	return self.manifest
}

// Debug stuff
func (self *StateDB) CreateOutputForDiff() {
	for _, stateObject := range self.stateObjects {
		stateObject.CreateOutputForDiff()
	}
}