path: root/ethchain/state.go

package ethchain

import (
    "github.com/ethereum/eth-go/ethcrypto"
    "github.com/ethereum/eth-go/ethtrie"
    "github.com/ethereum/eth-go/ethutil"
    "math/big"
)

// States within the ethereum protocol are used to store anything
// within the merkle trie. States take care of caching and storing
// nested states. It's the general query interface to retrieve:
// * Contracts
// * Accounts
type State struct {
    // The trie for this structure
    trie *ethtrie.Trie

    stateObjects map[string]*StateObject

    manifest *Manifest
}

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

// Iterate over each storage address and yield callback
func (s *State) EachStorage(cb ethtrie.EachCallback) {
    it := s.trie.NewIterator()
    it.Each(cb)
}

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

    return ethutil.Big0
}

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

    return 0
}

//
// Setting, updating & deleting state object methods
//

// Update the given state object and apply it to state trie
func (self *State) UpdateStateObject(stateObject *StateObject) {
    addr := stateObject.Address()

    ethutil.Config.Db.Put(ethcrypto.Sha3Bin(stateObject.Script()), stateObject.Script())

    self.trie.Update(string(addr), string(stateObject.RlpEncode()))

    self.manifest.AddObjectChange(stateObject)
}

// Delete the given state object and delete it from the state trie
func (self *State) 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 *State) GetStateObject(addr []byte) *StateObject {
    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.stateObjects[string(addr)] = stateObject

    return stateObject
}

// Retrieve a state object or create a new state object if nil
func (self *State) 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 *State) NewStateObject(addr []byte) *StateObject {
    statelogger.Infof("(+) %x\n", addr)

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

    return stateObject
}

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

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

func (s *State) Cmp(other *State) bool {
    return s.trie.Cmp(other.trie)
}

func (self *State) Copy() *State {
    if self.trie != nil {
        state := NewState(self.trie.Copy())
        for k, stateObject := range self.stateObjects {
            state.stateObjects[k] = stateObject.Copy()
        }

        return state
    }

    return nil
}

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

    self.trie = state.trie
    self.stateObjects = state.stateObjects
    //*self = *state
}

func (s *State) Root() interface{} {
    return s.trie.Root
}

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

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

        //stateObject.state.Reset()
        stateObject.Reset()
    }

    s.Empty()
}

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

        if stateObject.state == nil {
            continue
        }

        stateObject.state.Sync()
    }

    s.trie.Sync()

    s.Empty()
}

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

func (self *State) Update() {
    for _, stateObject := range self.stateObjects {
        if stateObject.remove {
            self.DeleteStateObject(stateObject)
        } else {
            stateObject.Sync()

            self.UpdateStateObject(stateObject)
        }
    }

    // FIXME trie delete is broken
    valid, t2 := ethtrie.ParanoiaCheck(self.trie)
    if !valid {
        self.trie = t2
    }
}

// Object manifest
//
// The object manifest is used to keep changes to the state so we can keep track of the changes
// that occurred during a state transitioning phase.
type Manifest struct {
    // XXX These will be handy in the future. Not important for now.
    objectAddresses  map[string]bool
    storageAddresses map[string]map[string]bool

    objectChanges  map[string]*StateObject
    storageChanges map[string]map[string]*big.Int
}

func NewManifest() *Manifest {
    m := &Manifest{objectAddresses: make(map[string]bool), storageAddresses: make(map[string]map[string]bool)}
    m.Reset()

    return m
}

func (m *Manifest) Reset() {
    m.objectChanges = make(map[string]*StateObject)
    m.storageChanges = make(map[string]map[string]*big.Int)
}

func (m *Manifest) AddObjectChange(stateObject *StateObject) {
    m.objectChanges[string(stateObject.Address())] = stateObject
}

func (m *Manifest) AddStorageChange(stateObject *StateObject, storageAddr []byte, storage *big.Int) {
    if m.storageChanges[string(stateObject.Address())] == nil {
        m.storageChanges[string(stateObject.Address())] = make(map[string]*big.Int)
    }

    m.storageChanges[string(stateObject.Address())][string(storageAddr)] = storage
}