path: root/ethchain/state_object.go

package ethchain

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

type Code []byte

func (self Code) String() string {
    return strings.Join(Disassemble(self), " ")
}

type StateObject struct {
    // Address of the object
    address []byte
    // Shared attributes
    Amount     *big.Int
    ScriptHash []byte
    Nonce      uint64
    // Contract related attributes
    state      *State
    script     Code
    initScript Code

    // Total gas pool is the total amount of gas currently
    // left if this object is the coinbase. Gas is directly
    // purchased of the coinbase.
    gasPool *big.Int

    // 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
}

// Converts an transaction in to a state object
func MakeContract(tx *Transaction, state *State) *StateObject {
    // Create contract if there's no recipient
    if tx.IsContract() {
        addr := tx.CreationAddress()

        contract := state.NewStateObject(addr)
        contract.initScript = tx.Data
        contract.state = NewState(ethtrie.NewTrie(ethutil.Config.Db, ""))

        return contract
    }

    return nil
}

func NewStateObject(addr []byte) *StateObject {
    object := &StateObject{address: addr, Amount: new(big.Int), gasPool: new(big.Int)}
    object.state = NewState(ethtrie.NewTrie(ethutil.Config.Db, ""))

    return object
}

func NewContract(address []byte, Amount *big.Int, root []byte) *StateObject {
    contract := &StateObject{address: address, Amount: Amount, Nonce: 0}
    contract.state = NewState(ethtrie.NewTrie(ethutil.Config.Db, string(root)))

    return contract
}

// Returns a newly created account
func NewAccount(address []byte, amount *big.Int) *StateObject {
    account := &StateObject{address: address, Amount: amount, Nonce: 0}

    return account
}

func NewStateObjectFromBytes(address, data []byte) *StateObject {
    object := &StateObject{address: address}
    object.RlpDecode(data)

    return object
}

func (self *StateObject) MarkForDeletion() {
    self.remove = true
}

func (c *StateObject) GetAddr(addr []byte) *ethutil.Value {
    return ethutil.NewValueFromBytes([]byte(c.state.trie.Get(string(addr))))
}

func (c *StateObject) SetAddr(addr []byte, value interface{}) {
    c.state.trie.Update(string(addr), string(ethutil.NewValue(value).Encode()))
}

func (c *StateObject) SetStorage(num *big.Int, val *ethutil.Value) {
    addr := ethutil.BigToBytes(num, 256)

    if val.BigInt().Cmp(ethutil.Big0) == 0 {
        c.state.trie.Delete(string(addr))

        return
    }

    c.SetAddr(addr, val)
}

func (c *StateObject) GetStorage(num *big.Int) *ethutil.Value {
    nb := ethutil.BigToBytes(num, 256)

    return c.GetAddr(nb)
}

func (c *StateObject) GetInstr(pc *big.Int) *ethutil.Value {
    if int64(len(c.script)-1) < pc.Int64() {
        return ethutil.NewValue(0)
    }

    return ethutil.NewValueFromBytes([]byte{c.script[pc.Int64()]})
}

func (c *StateObject) AddAmount(amount *big.Int) {
    c.SetAmount(new(big.Int).Add(c.Amount, amount))

    statelogger.Infof("%x: #%d %v (+ %v)\n", c.Address(), c.Nonce, c.Amount, amount)
}

func (c *StateObject) SubAmount(amount *big.Int) {
    c.SetAmount(new(big.Int).Sub(c.Amount, amount))

    statelogger.Infof("%x: #%d %v (- %v)\n", c.Address(), c.Nonce, c.Amount, amount)
}

func (c *StateObject) SetAmount(amount *big.Int) {
    c.Amount = amount
}

//
// Gas setters and getters
//

// Return the gas back to the origin. Used by the Virtual machine or Closures
func (c *StateObject) ReturnGas(gas, price *big.Int, state *State) {}
func (c *StateObject) ConvertGas(gas, price *big.Int) error {
    total := new(big.Int).Mul(gas, price)
    if total.Cmp(c.Amount) > 0 {
        return fmt.Errorf("insufficient amount: %v, %v", c.Amount, total)
    }

    c.SubAmount(total)

    return nil
}

func (self *StateObject) SetGasPool(gasLimit *big.Int) {
    self.gasPool = new(big.Int).Set(gasLimit)

    statelogger.DebugDetailf("%x: fuel (+ %v)", self.Address(), self.gasPool)
}

func (self *StateObject) BuyGas(gas, price *big.Int) error {
    if self.gasPool.Cmp(gas) < 0 {
        return GasLimitError(self.gasPool, gas)
    }

    rGas := new(big.Int).Set(gas)
    rGas.Mul(rGas, price)

    self.AddAmount(rGas)

    return nil
}

func (self *StateObject) RefundGas(gas, price *big.Int) {
    self.gasPool.Add(self.gasPool, gas)

    rGas := new(big.Int).Set(gas)
    rGas.Mul(rGas, price)

    self.Amount.Sub(self.Amount, rGas)
}

func (self *StateObject) Copy() *StateObject {
    stateObject := NewStateObject(self.Address())
    stateObject.Amount.Set(self.Amount)
    stateObject.ScriptHash = ethutil.CopyBytes(self.ScriptHash)
    stateObject.Nonce = self.Nonce
    if self.state != nil {
        stateObject.state = self.state.Copy()
    }
    stateObject.script = ethutil.CopyBytes(self.script)
    stateObject.initScript = ethutil.CopyBytes(self.initScript)

    return stateObject
}

func (self *StateObject) Set(stateObject *StateObject) {
    *self = *stateObject
}

//
// Attribute accessors
//

func (c *StateObject) State() *State {
    return c.state
}

func (c *StateObject) N() *big.Int {
    return big.NewInt(int64(c.Nonce))
}

// Returns the address of the contract/account
func (c *StateObject) Address() []byte {
    return c.address
}

// Returns the main script body
func (c *StateObject) Script() Code {
    return c.script
}

// Returns the initialization script
func (c *StateObject) Init() Code {
    return c.initScript
}

//
// Encoding
//

// State object encoding methods
func (c *StateObject) RlpEncode() []byte {
    var root interface{}
    if c.state != nil {
        root = c.state.trie.Root
    } else {
        root = ""
    }

    return ethutil.Encode([]interface{}{c.Nonce, c.Amount, root, ethcrypto.Sha3Bin(c.script)})
}

func (c *StateObject) RlpDecode(data []byte) {
    decoder := ethutil.NewValueFromBytes(data)

    c.Nonce = decoder.Get(0).Uint()
    c.Amount = decoder.Get(1).BigInt()
    c.state = NewState(ethtrie.NewTrie(ethutil.Config.Db, decoder.Get(2).Interface()))

    c.ScriptHash = decoder.Get(3).Bytes()

    c.script, _ = ethutil.Config.Db.Get(c.ScriptHash)
}

// Storage change object. Used by the manifest for notifying changes to
// the sub channels.
type StorageState struct {
    StateAddress []byte
    Address      []byte
    Value        *big.Int
}