path: root/core/block_processor.go

package core

import (
    "bytes"
    "errors"
    "fmt"
    "math/big"
    "sync"

    "github.com/ethereum/go-ethereum/core/types"
    "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/p2p"
    "github.com/ethereum/go-ethereum/pow"
    "github.com/ethereum/go-ethereum/pow/ezp"
    "github.com/ethereum/go-ethereum/state"
    "gopkg.in/fatih/set.v0"
)

var statelogger = logger.NewLogger("BLOCK")

type EthManager interface {
    BlockProcessor() *BlockProcessor
    ChainManager() *ChainManager
    TxPool() *TxPool
    PeerCount() int
    IsMining() bool
    IsListening() bool
    Peers() []*p2p.Peer
    KeyManager() *crypto.KeyManager
    ClientIdentity() p2p.ClientIdentity
    Db() ethutil.Database
    EventMux() *event.TypeMux
}

type BlockProcessor 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.PoW

    txpool *TxPool

    // 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 *types.Block

    events event.Subscription

    eventMux *event.TypeMux
}

func NewBlockProcessor(txpool *TxPool, chainManager *ChainManager, eventMux *event.TypeMux) *BlockProcessor {
    sm := &BlockProcessor{
        mem:      make(map[string]*big.Int),
        Pow:      ezp.New(),
        bc:       chainManager,
        eventMux: eventMux,
        txpool:   txpool,
    }

    return sm
}

func (sm *BlockProcessor) TransitionState(statedb *state.StateDB, parent, block *types.Block) (receipts types.Receipts, err error) {
    coinbase := statedb.GetOrNewStateObject(block.Header().Coinbase)
    coinbase.SetGasPool(CalcGasLimit(parent, block))

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

    return receipts, nil
}

func (self *BlockProcessor) ApplyTransactions(coinbase *state.StateObject, state *state.StateDB, block *types.Block, txs types.Transactions, transientProcess bool) (types.Receipts, types.Transactions, types.Transactions, types.Transactions, error) {
    var (
        receipts           types.Receipts
        handled, unhandled types.Transactions
        erroneous          types.Transactions
        totalUsedGas       = big.NewInt(0)
        err                error
        cumulativeSum      = new(big.Int)
    )

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(NewEnv(state, self.bc, tx, block), tx, cb)
        _, err = st.TransitionState()
        if err != nil {
            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
            }
        }

        txGas.Sub(txGas, st.gas)
        cumulativeSum.Add(cumulativeSum, new(big.Int).Mul(txGas, tx.GasPrice()))

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

        cumulative := new(big.Int).Set(totalUsedGas.Add(totalUsedGas, txGas))
        receipt := types.NewReceipt(state.Root(), cumulative)
        receipt.SetLogs(state.Logs())
        receipt.Bloom = types.CreateBloom(types.Receipts{receipt})
        chainlogger.Debugln(receipt)

        // Notify all subscribers
        if !transientProcess {
            go self.eventMux.Post(TxPostEvent{tx})
        }

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

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

    block.Reward = cumulativeSum
    block.Header().GasUsed = totalUsedGas

    return receipts, handled, unhandled, erroneous, err
}

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

    header := block.Header()
    if sm.bc.HasBlock(header.Hash()) {
        return nil, nil, &KnownBlockError{header.Number, header.Hash()}
    }

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

    return sm.ProcessWithParent(block, parent)
}

func (sm *BlockProcessor) ProcessWithParent(block, parent *types.Block) (td *big.Int, messages state.Messages, err error) {
    sm.lastAttemptedBlock = block

    state := state.New(parent.Trie().Copy())

    // Block validation
    if err = sm.ValidateBlock(block, parent); err != nil {
        return
    }

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

    header := block.Header()

    rbloom := types.CreateBloom(receipts)
    if bytes.Compare(rbloom, header.Bloom) != 0 {
        err = fmt.Errorf("unable to replicate block's bloom=%x", rbloom)
        return
    }

    txSha := types.DeriveSha(block.Transactions())
    if bytes.Compare(txSha, header.TxHash) != 0 {
        err = fmt.Errorf("validating transaction root. received=%x got=%x", header.TxHash, txSha)
        return
    }

    receiptSha := types.DeriveSha(receipts)
    if bytes.Compare(receiptSha, header.ReceiptHash) != 0 {
        fmt.Println("receipts", receipts)
        err = fmt.Errorf("validating receipt root. received=%x got=%x", header.ReceiptHash, receiptSha)
        return
    }

    if err = sm.AccumelateRewards(state, block, parent); err != nil {
        return
    }

    state.Update(ethutil.Big0)

    if !bytes.Equal(header.Root, state.Root()) {
        err = fmt.Errorf("invalid merkle root. received=%x got=%x", header.Root, state.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()

        state.Manifest().SetHash(block.Hash())

        messages := state.Manifest().Messages
        state.Manifest().Reset()

        chainlogger.Infof("processed block #%d (%x...)\n", header.Number, block.Hash()[0:4])

        sm.txpool.RemoveSet(block.Transactions())

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

func (sm *BlockProcessor) CalculateTD(block *types.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.Header().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
    }

    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 *BlockProcessor) ValidateBlock(block, parent *types.Block) error {
    if len(block.Header().Extra) > 1024 {
        return fmt.Errorf("Block extra data too long (%d)", len(block.Header().Extra))
    }

    expd := CalcDifficulty(block, parent)
    if expd.Cmp(block.Header().Difficulty) < 0 {
        fmt.Println("parent\n", parent)
        return fmt.Errorf("Difficulty check failed for block %v, %v", block.Header().Difficulty, expd)
    }

    diff := block.Header().Time - parent.Header().Time
    if diff < 0 {
        return ValidationError("Block timestamp less then prev block %v (%v - %v)", diff, block.Header().Time, sm.bc.CurrentBlock().Header().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 /*block.HashNoNonce(), block.Difficulty, block.Nonce*/) {
        return ValidationError("Block's nonce is invalid (= %v)", ethutil.Bytes2Hex(block.Header().Nonce))
    }

    return nil
}

func (sm *BlockProcessor) AccumelateRewards(statedb *state.StateDB, block, parent *types.Block) error {
    reward := new(big.Int).Set(BlockReward)

    knownUncles := set.New()
    for _, uncle := range parent.Uncles() {
        knownUncles.Add(string(uncle.Hash()))
    }

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

        uncleParent := sm.bc.GetBlock(uncle.ParentHash)
        if uncleParent == nil {
            return UncleError(fmt.Sprintf("Uncle's parent unknown (%x)", uncle.ParentHash[0:4]))
        }

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

        if knownUncles.Has(string(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 := statedb.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 := statedb.GetAccount(block.Header().Coinbase)
    // Reward amount of ether to the coinbase address
    account.AddAmount(reward)

    statedb.Manifest().AddMessage(&state.Message{
        To:        block.Header().Coinbase,
        Input:     nil,
        Origin:    nil,
        Timestamp: int64(block.Header().Time), Coinbase: block.Header().Coinbase, Number: block.Header().Number,
        Value: new(big.Int).Add(reward, block.Reward),
    })

    return nil
}

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

    sm.lastAttemptedBlock = block

    var (
        parent = sm.bc.GetBlock(block.Header().ParentHash)
        state  = state.New(parent.Trie().Copy())
    )

    defer state.Reset()

    sm.TransitionState(state, parent, block)
    sm.AccumelateRewards(state, block, parent)

    return state.Manifest().Messages, nil
}