path: root/chain/block_manager.go

package chain

import (
    "bytes"
    "container/list"
    "errors"
    "fmt"
    "math/big"
    "os"
    "sync"
    "time"

    "github.com/ethereum/go-ethereum/crypto"
    "github.com/ethereum/go-ethereum/ethutil"
    "github.com/ethereum/go-ethereum/event"
    "github.com/ethereum/go-ethereum/logger"
    "github.com/ethereum/go-ethereum/state"
    "github.com/ethereum/go-ethereum/wire"
)

var statelogger = logger.NewLogger("BLOCK")

type Peer interface {
    Inbound() bool
    LastSend() time.Time
    LastPong() int64
    Host() []byte
    Port() uint16
    Version() string
    PingTime() string
    Connected() *int32
    Caps() *ethutil.Value
}

type EthManager interface {
    BlockManager() *BlockManager
    ChainManager() *ChainManager
    TxPool() *TxPool
    Broadcast(msgType wire.MsgType, data []interface{})
    PeerCount() int
    IsMining() bool
    IsListening() bool
    Peers() *list.List
    KeyManager() *crypto.KeyManager
    ClientIdentity() wire.ClientIdentity
    Db() ethutil.Database
    EventMux() *event.TypeMux
}

type BlockManager struct {
    // Mutex for locking the block processor. Blocks can only be handled one at a time
    mutex sync.Mutex
    // Canonical block chain
    bc *ChainManager
    // non-persistent key/value memory storage
    mem map[string]*big.Int
    // Proof of work used for validating
    Pow PoW
    // The ethereum manager interface
    eth EthManager
    // The managed states
    // Transiently state. The trans state isn't ever saved, validated and
    // it could be used for setting account nonces without effecting
    // the main states.
    transState *state.State
    // Mining state. The mining state is used purely and solely by the mining
    // operation.
    miningState *state.State

    // The last attempted block is mainly used for debugging purposes
    // This does not have to be a valid block and will be set during
    // 'Process' & canonical validation.
    lastAttemptedBlock *Block

    events event.Subscription
}

func NewBlockManager(ethereum EthManager) *BlockManager {
    sm := &BlockManager{
        mem: make(map[string]*big.Int),
        Pow: &EasyPow{},
        eth: ethereum,
        bc:  ethereum.ChainManager(),
    }
    sm.transState = ethereum.ChainManager().CurrentBlock.State().Copy()
    sm.miningState = ethereum.ChainManager().CurrentBlock.State().Copy()

    return sm
}

func (self *BlockManager) Start() {
    statelogger.Debugln("Starting state manager")
    self.events = self.eth.EventMux().Subscribe(Blocks(nil))
    go self.updateThread()
}

func (self *BlockManager) Stop() {
    statelogger.Debugln("Stopping state manager")
    self.events.Unsubscribe()
}

func (self *BlockManager) updateThread() {
    for ev := range self.events.Chan() {
        for _, block := range ev.(Blocks) {
            _, err := self.Process(block)
            if err != nil {
                statelogger.Infoln(err)
                statelogger.Debugf("Block #%v failed (%x...)\n", block.Number, block.Hash()[0:4])
                statelogger.Debugln(block)
                break
            }
        }
    }
}

func (sm *BlockManager) CurrentState() *state.State {
    return sm.eth.ChainManager().CurrentBlock.State()
}

func (sm *BlockManager) TransState() *state.State {
    return sm.transState
}

func (sm *BlockManager) MiningState() *state.State {
    return sm.miningState
}

func (sm *BlockManager) NewMiningState() *state.State {
    sm.miningState = sm.eth.ChainManager().CurrentBlock.State().Copy()

    return sm.miningState
}

func (sm *BlockManager) ChainManager() *ChainManager {
    return sm.bc
}

func (self *BlockManager) ProcessTransactions(coinbase *state.StateObject, state *state.State, block, parent *Block, txs Transactions) (Receipts, Transactions, Transactions, Transactions, error) {
    var (
        receipts           Receipts
        handled, unhandled Transactions
        erroneous          Transactions
        totalUsedGas       = big.NewInt(0)
        err                error
    )

done:
    for i, tx := range txs {
        // If we are mining this block and validating we want to set the logs back to 0
        state.EmptyLogs()

        txGas := new(big.Int).Set(tx.Gas)

        cb := state.GetStateObject(coinbase.Address())
        st := NewStateTransition(cb, tx, state, block)
        err = st.TransitionState()
        if err != nil {
            statelogger.Infoln(err)
            switch {
            case IsNonceErr(err):
                err = nil // ignore error
                continue
            case IsGasLimitErr(err):
                unhandled = txs[i:]

                break done
            default:
                statelogger.Infoln(err)
                erroneous = append(erroneous, tx)
                err = nil
                continue
            }
        }

        // Update the state with pending changes
        state.Update()

        txGas.Sub(txGas, st.gas)
        cumulative := new(big.Int).Set(totalUsedGas.Add(totalUsedGas, txGas))
        receipt := &Receipt{ethutil.CopyBytes(state.Root().([]byte)), cumulative, LogsBloom(state.Logs()).Bytes(), state.Logs()}

        if i < len(block.Receipts()) {
            original := block.Receipts()[i]
            if !original.Cmp(receipt) {
                if ethutil.Config.Diff {
                    os.Exit(1)
                }

                err := fmt.Errorf("#%d receipt failed (r) %v ~ %x  <=>  (c) %v ~ %x (%x...)", i+1, original.CumulativeGasUsed, original.PostState[0:4], receipt.CumulativeGasUsed, receipt.PostState[0:4], tx.Hash()[0:4])

                return nil, nil, nil, nil, err
            }
        }

        // Notify all subscribers
        go self.eth.EventMux().Post(TxPostEvent{tx})

        receipts = append(receipts, receipt)
        handled = append(handled, tx)

        if ethutil.Config.Diff && ethutil.Config.DiffType == "all" {
            state.CreateOutputForDiff()
        }
    }

    parent.GasUsed = totalUsedGas

    return receipts, handled, unhandled, erroneous, err
}

func (sm *BlockManager) Process(block *Block) (td *big.Int, err error) {
    // Processing a blocks may never happen simultaneously
    sm.mutex.Lock()
    defer sm.mutex.Unlock()

    if sm.bc.HasBlock(block.Hash()) {
        return nil, nil
    }

    if !sm.bc.HasBlock(block.PrevHash) {
        return nil, ParentError(block.PrevHash)
    }
    parent := sm.bc.GetBlock(block.PrevHash)

    return sm.ProcessWithParent(block, parent)
}

func (sm *BlockManager) ProcessWithParent(block, parent *Block) (td *big.Int, err error) {
    sm.lastAttemptedBlock = block

    state := parent.State()

    // Defer the Undo on the Trie. If the block processing happened
    // we don't want to undo but since undo only happens on dirty
    // nodes this won't happen because Commit would have been called
    // before that.
    defer state.Reset()

    if ethutil.Config.Diff && ethutil.Config.DiffType == "all" {
        fmt.Printf("## %x %x ##\n", block.Hash(), block.Number)
    }

    txSha := DeriveSha(block.transactions)
    if bytes.Compare(txSha, block.TxSha) != 0 {
        return nil, fmt.Errorf("Error validating transaction sha. Received %x, got %x", block.TxSha, txSha)
    }

    receipts, err := sm.ApplyDiff(state, parent, block)
    if err != nil {
        return nil, err
    }

    receiptSha := DeriveSha(receipts)
    if bytes.Compare(receiptSha, block.ReceiptSha) != 0 {
        return nil, fmt.Errorf("Error validating receipt sha. Received %x, got %x", block.ReceiptSha, receiptSha)
    }

    // Block validation
    if err = sm.ValidateBlock(block, parent); err != nil {
        statelogger.Errorln("Error validating block:", err)
        return nil, err
    }

    if err = sm.AccumelateRewards(state, block, parent); err != nil {
        statelogger.Errorln("Error accumulating reward", err)
        return nil, err
    }

    if bytes.Compare(CreateBloom(block), block.LogsBloom) != 0 {
        return nil, errors.New("Unable to replicate block's bloom")
    }

    state.Update()

    if !block.State().Cmp(state) {
        err = fmt.Errorf("Invalid merkle root.\nrec: %x\nis:  %x", block.State().Trie.Root, state.Trie.Root)
        return
    }

    // Calculate the new total difficulty and sync back to the db
    if td, ok := sm.CalculateTD(block); ok {
        // Sync the current block's state to the database and cancelling out the deferred Undo
        state.Sync()

        // TODO at this point we should also insert LOGS in to a database

        sm.transState = state.Copy()

        state.Manifest().Reset()

        sm.eth.TxPool().RemoveSet(block.Transactions())

        return td, nil
    } else {
        return nil, errors.New("total diff failed")
    }
}

func (sm *BlockManager) ApplyDiff(state *state.State, parent, block *Block) (receipts Receipts, err error) {
    coinbase := state.GetOrNewStateObject(block.Coinbase)
    coinbase.SetGasPool(block.CalcGasLimit(parent))

    // Process the transactions on to current block
    receipts, _, _, _, err = sm.ProcessTransactions(coinbase, state, block, parent, block.Transactions())
    if err != nil {
        return nil, err
    }

    return receipts, nil
}

func (sm *BlockManager) CalculateTD(block *Block) (*big.Int, bool) {
    uncleDiff := new(big.Int)
    for _, uncle := range block.Uncles {
        uncleDiff = uncleDiff.Add(uncleDiff, uncle.Difficulty)
    }

    // TD(genesis_block) = 0 and TD(B) = TD(B.parent) + sum(u.difficulty for u in B.uncles) + B.difficulty
    td := new(big.Int)
    td = td.Add(sm.bc.TD, uncleDiff)
    td = td.Add(td, block.Difficulty)

    // The new TD will only be accepted if the new difficulty is
    // is greater than the previous.
    if td.Cmp(sm.bc.TD) > 0 {
        return td, true

        // Set the new total difficulty back to the block chain
        //sm.bc.SetTotalDifficulty(td)
    }

    return nil, false
}

// Validates the current block. Returns an error if the block was invalid,
// an uncle or anything that isn't on the current block chain.
// Validation validates easy over difficult (dagger takes longer time = difficult)
func (sm *BlockManager) ValidateBlock(block, parent *Block) error {
    expd := CalcDifficulty(block, parent)
    if expd.Cmp(block.Difficulty) < 0 {
        return fmt.Errorf("Difficulty check failed for block %v, %v", block.Difficulty, expd)
    }

    diff := block.Time - parent.Time
    if diff < 0 {
        return ValidationError("Block timestamp less then prev block %v (%v - %v)", diff, block.Time, sm.bc.CurrentBlock.Time)
    }

    /* XXX
    // New blocks must be within the 15 minute range of the last block.
    if diff > int64(15*time.Minute) {
        return ValidationError("Block is too far in the future of last block (> 15 minutes)")
    }
    */

    // Verify the nonce of the block. Return an error if it's not valid
    if !sm.Pow.Verify(block.HashNoNonce(), block.Difficulty, block.Nonce) {
        return ValidationError("Block's nonce is invalid (= %v)", ethutil.Bytes2Hex(block.Nonce))
    }

    return nil
}

func (sm *BlockManager) AccumelateRewards(state *state.State, block, parent *Block) error {
    reward := new(big.Int).Set(BlockReward)

    knownUncles := ethutil.Set(parent.Uncles)
    nonces := ethutil.NewSet(block.Nonce)
    for _, uncle := range block.Uncles {
        if nonces.Include(uncle.Nonce) {
            // Error not unique
            return UncleError("Uncle not unique")
        }

        uncleParent := sm.bc.GetBlock(uncle.PrevHash)
        if uncleParent == nil {
            return UncleError("Uncle's parent unknown")
        }

        if uncleParent.Number.Cmp(new(big.Int).Sub(parent.Number, big.NewInt(6))) < 0 {
            return UncleError("Uncle too old")
        }

        if knownUncles.Include(uncle.Hash()) {
            return UncleError("Uncle in chain")
        }

        nonces.Insert(uncle.Nonce)

        r := new(big.Int)
        r.Mul(BlockReward, big.NewInt(15)).Div(r, big.NewInt(16))

        uncleAccount := state.GetAccount(uncle.Coinbase)
        uncleAccount.AddAmount(r)

        reward.Add(reward, new(big.Int).Div(BlockReward, big.NewInt(32)))
    }

    // Get the account associated with the coinbase
    account := state.GetAccount(block.Coinbase)
    // Reward amount of ether to the coinbase address
    account.AddAmount(reward)

    return nil
}

func (sm *BlockManager) GetMessages(block *Block) (messages []*state.Message, err error) {
    if !sm.bc.HasBlock(block.PrevHash) {
        return nil, ParentError(block.PrevHash)
    }

    sm.lastAttemptedBlock = block

    var (
        parent = sm.bc.GetBlock(block.PrevHash)
        state  = parent.State().Copy()
    )

    defer state.Reset()

    sm.ApplyDiff(state, parent, block)

    sm.AccumelateRewards(state, block, parent)

    return state.Manifest().Messages, nil
}