path: root/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()
    }
}