package core
import (
"fmt"
"math/big"
"sync"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/state"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/event"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/params"
"github.com/ethereum/go-ethereum/pow"
"github.com/ethereum/go-ethereum/rlp"
"gopkg.in/fatih/set.v0"
)
var statelogger = logger.NewLogger("BLOCK")
type BlockProcessor struct {
db common.Database
extraDb common.Database
// 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(db, extra common.Database, pow pow.PoW, txpool *TxPool, chainManager *ChainManager, eventMux *event.TypeMux) *BlockProcessor {
sm := &BlockProcessor{
db: db,
extraDb: extra,
mem: make(map[string]*big.Int),
Pow: pow,
bc: chainManager,
eventMux: eventMux,
txpool: txpool,
}
return sm
}
func (sm *BlockProcessor) TransitionState(statedb *state.StateDB, parent, block *types.Block, transientProcess bool) (receipts types.Receipts, err error) {
coinbase := statedb.GetOrNewStateObject(block.Header().Coinbase)
coinbase.SetGasPool(block.Header().GasLimit)
// Process the transactions on to parent state
receipts, err = sm.ApplyTransactions(coinbase, statedb, block, block.Transactions(), transientProcess)
if err != nil {
return nil, err
}
return receipts, nil
}
func (self *BlockProcessor) ApplyTransaction(coinbase *state.StateObject, statedb *state.StateDB, block *types.Block, tx *types.Transaction, usedGas *big.Int, transientProcess bool) (*types.Receipt, *big.Int, error) {
// If we are mining this block and validating we want to set the logs back to 0
statedb.EmptyLogs()
cb := statedb.GetStateObject(coinbase.Address())
_, gas, err := ApplyMessage(NewEnv(statedb, self.bc, tx, block), tx, cb)
if err != nil && (IsNonceErr(err) || state.IsGasLimitErr(err) || IsInvalidTxErr(err)) {
// If the account is managed, remove the invalid nonce.
from, _ := tx.From()
self.bc.TxState().RemoveNonce(from, tx.Nonce())
return nil, nil, err
}
// Update the state with pending changes
statedb.Update(nil)
cumulative := new(big.Int).Set(usedGas.Add(usedGas, gas))
receipt := types.NewReceipt(statedb.Root().Bytes(), cumulative)
receipt.SetLogs(statedb.Logs())
receipt.Bloom = types.CreateBloom(types.Receipts{receipt})
chainlogger.Debugln(receipt)
// Notify all subscribers
if !transientProcess {
go self.eventMux.Post(TxPostEvent{tx})
logs := statedb.Logs()
go self.eventMux.Post(logs)
}
return receipt, gas, err
}
func (self *BlockProcessor) ChainManager() *ChainManager {
return self.bc
}
func (self *BlockProcessor) ApplyTransactions(coinbase *state.StateObject, statedb *state.StateDB, block *types.Block, txs types.Transactions, transientProcess bool) (types.Receipts, error) {
var (
receipts types.Receipts
totalUsedGas = big.NewInt(0)
err error
cumulativeSum = new(big.Int)
)
for _, tx := range txs {
receipt, txGas, err := self.ApplyTransaction(coinbase, statedb, block, tx, totalUsedGas, transientProcess)
if err != nil && (IsNonceErr(err) || state.IsGasLimitErr(err) || IsInvalidTxErr(err)) {
return nil, err
}
if err != nil {
statelogger.Infoln("TX err:", err)
}
receipts = append(receipts, receipt)
cumulativeSum.Add(cumulativeSum, new(big.Int).Mul(txGas, tx.GasPrice()))
}
if block.GasUsed().Cmp(totalUsedGas) != 0 {
return nil, ValidationError(fmt.Sprintf("gas used error (%v / %v)", block.GasUsed(), totalUsedGas))
}
if transientProcess {
go self.eventMux.Post(PendingBlockEvent{block, statedb.Logs()})
}
return receipts, err
}
// Process block will attempt to process the given block's transactions and applies them
// on top of the block's parent state (given it exists) and will return wether it was
// successful or not.
func (sm *BlockProcessor) Process(block *types.Block) (td *big.Int, logs state.Logs, 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, logs state.Logs, err error) {
sm.lastAttemptedBlock = block
// Create a new state based on the parent's root (e.g., create copy)
state := state.New(parent.Root(), sm.db)
// track (possible) uncle block
var uncle bool
// Block validation
if err = sm.ValidateHeader(block.Header(), parent.Header()); err != nil {
if err != BlockEqualTSErr {
return
}
err = nil
uncle = true
}
// There can be at most two uncles
if len(block.Uncles()) > 2 {
return nil, nil, ValidationError("Block can only contain one uncle (contained %v)", len(block.Uncles()))
}
receipts, err := sm.TransitionState(state, parent, block, false)
if err != nil {
return
}
header := block.Header()
// Validate the received block's bloom with the one derived from the generated receipts.
// For valid blocks this should always validate to true.
rbloom := types.CreateBloom(receipts)
if rbloom != header.Bloom {
err = fmt.Errorf("unable to replicate block's bloom=%x", rbloom)
return
}
// The transactions Trie's root (R = (Tr [[i, RLP(T1)], [i, RLP(T2)], ... [n, RLP(Tn)]]))
// can be used by light clients to make sure they've received the correct Txs
txSha := types.DeriveSha(block.Transactions())
if txSha != header.TxHash {
err = fmt.Errorf("validating transaction root. received=%x got=%x", header.TxHash, txSha)
return
}
// Tre receipt Trie's root (R = (Tr [[H1, R1], ... [Hn, R1]]))
receiptSha := types.DeriveSha(receipts)
if receiptSha != header.ReceiptHash {
err = fmt.Errorf("validating receipt root. received=%x got=%x", header.ReceiptHash, receiptSha)
return
}
// Accumulate static rewards; block reward, uncle's and uncle inclusion.
if err = sm.AccumulateRewards(state, block, parent); err != nil {
return
}
// Commit state objects/accounts to a temporary trie (does not save)
// used to calculate the state root.
state.Update(common.Big0)
if header.Root != state.Root() {
err = fmt.Errorf("invalid merkle root. received=%x got=%x", header.Root, state.Root())
return
}
// Calculate the td for this block
td = CalculateTD(block, parent)
// Sync the current block's state to the database
state.Sync()
if !uncle {
// Remove transactions from the pool
sm.txpool.RemoveSet(block.Transactions())
}
// This puts transactions in a extra db for rpc
for i, tx := range block.Transactions() {
putTx(sm.extraDb, tx, block, uint64(i))
}
if uncle {
chainlogger.Infof("found possible uncle block #%d (%x...)\n", header.Number, block.Hash().Bytes()[0:4])
return td, nil, BlockEqualTSErr
} else {
chainlogger.Infof("processed block #%d (%d TXs %d UNCs) (%x...)\n", header.Number, len(block.Transactions()), len(block.Uncles()), block.Hash().Bytes()[0:4])
}
return td, state.Logs(), nil
}
// 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) ValidateHeader(block, parent *types.Header) error {
if big.NewInt(int64(len(block.Extra))).Cmp(params.MaximumExtraDataSize) == 1 {
return fmt.Errorf("Block extra data too long (%d)", len(block.Extra))
}
expd := CalcDifficulty(block, parent)
if expd.Cmp(block.Difficulty) != 0 {
return fmt.Errorf("Difficulty check failed for block %v, %v", block.Difficulty, expd)
}
// block.gasLimit - parent.gasLimit <= parent.gasLimit / GasLimitBoundDivisor
a := new(big.Int).Sub(block.GasLimit, parent.GasLimit)
a.Abs(a)
b := new(big.Int).Div(parent.GasLimit, params.GasLimitBoundDivisor)
if !(a.Cmp(b) < 0) || (block.GasLimit.Cmp(params.MinGasLimit) == -1) {
return fmt.Errorf("GasLimit check failed for block %v (%v > %v)", block.GasLimit, a, b)
}
if int64(block.Time) > time.Now().Unix() {
return BlockFutureErr
}
if new(big.Int).Sub(block.Number, parent.Number).Cmp(big.NewInt(1)) != 0 {
return BlockNumberErr
}
// Verify the nonce of the block. Return an error if it's not valid
if !sm.Pow.Verify(types.NewBlockWithHeader(block)) {
return ValidationError("Block's nonce is invalid (= %x)", block.Nonce)
}
if block.Time <= parent.Time {
return BlockEqualTSErr //ValidationError("Block timestamp equal or less than previous block (%v - %v)", block.Time, parent.Time)
}
return nil
}
func (sm *BlockProcessor) AccumulateRewards(statedb *state.StateDB, block, parent *types.Block) error {
reward := new(big.Int).Set(BlockReward)
ancestors := set.New()
uncles := set.New()
ancestorHeaders := make(map[common.Hash]*types.Header)
for _, ancestor := range sm.bc.GetAncestors(block, 7) {
ancestorHeaders[ancestor.Hash()] = ancestor.Header()
ancestors.Add(ancestor.Hash())
// Include ancestors uncles in the uncle set. Uncles must be unique.
for _, uncle := range ancestor.Uncles() {
uncles.Add(uncle.Hash())
}
}
uncles.Add(block.Hash())
for _, uncle := range block.Uncles() {
if uncles.Has(uncle.Hash()) {
// Error not unique
return UncleError("Uncle not unique")
}
uncles.Add(uncle.Hash())
if ancestors.Has(uncle.Hash()) {
return UncleError("Uncle is ancestor")
}
if !ancestors.Has(uncle.ParentHash) {
return UncleError(fmt.Sprintf("Uncle's parent unknown (%x)", uncle.ParentHash[0:4]))
}
if err := sm.ValidateHeader(uncle, ancestorHeaders[uncle.ParentHash]); err != nil && err != BlockEqualTSErr {
return ValidationError(fmt.Sprintf("%v", err))
}
num := new(big.Int).Add(big.NewInt(8), uncle.Number)
num.Sub(num, block.Number())
r := new(big.Int)
r.Mul(BlockReward, num)
r.Div(r, big.NewInt(8))
statedb.AddBalance(uncle.Coinbase, r)
reward.Add(reward, new(big.Int).Div(BlockReward, big.NewInt(32)))
}
// Get the account associated with the coinbase
statedb.AddBalance(block.Header().Coinbase, reward)
return nil
}
func (sm *BlockProcessor) GetLogs(block *types.Block) (logs state.Logs, 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.Root(), sm.db)
)
sm.TransitionState(state, parent, block, true)
sm.AccumulateRewards(state, block, parent)
return state.Logs(), nil
}
func putTx(db common.Database, tx *types.Transaction, block *types.Block, i uint64) {
rlpEnc, err := rlp.EncodeToBytes(tx)
if err != nil {
statelogger.Infoln("Failed encoding tx", err)
return
}
db.Put(tx.Hash().Bytes(), rlpEnc)
var txExtra struct {
BlockHash common.Hash
BlockIndex uint64
Index uint64
}
txExtra.BlockHash = block.Hash()
txExtra.BlockIndex = block.NumberU64()
txExtra.Index = i
rlpMeta, err := rlp.EncodeToBytes(txExtra)
if err != nil {
statelogger.Infoln("Failed encoding meta", err)
return
}
db.Put(append(tx.Hash().Bytes(), 0x0001), rlpMeta)
}