path: root/miner/worker.go

package miner

import (
    "fmt"
    "math/big"
    "sort"
    "sync"
    "sync/atomic"
    "time"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/core"
    "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/pow"
    "gopkg.in/fatih/set.v0"
)

var jsonlogger = logger.NewJsonLogger()

type environment struct {
    totalUsedGas *big.Int
    state        *state.StateDB
    coinbase     *state.StateObject
    block        *types.Block
    family       *set.Set
    uncles       *set.Set
}

func env(block *types.Block, eth core.Backend) *environment {
    state := state.New(block.Root(), eth.StateDb())
    env := &environment{
        totalUsedGas: new(big.Int),
        state:        state,
        block:        block,
        family:       set.New(),
        uncles:       set.New(),
        coinbase:     state.GetOrNewStateObject(block.Coinbase()),
    }

    return env
}

type Work struct {
    Number    uint64
    Nonce     uint64
    MixDigest []byte
    SeedHash  []byte
}

type Agent interface {
    Work() chan<- *types.Block
    SetReturnCh(chan<- *types.Block)
    Stop()
    Start()
    GetHashRate() int64
}

type worker struct {
    mu sync.Mutex

    agents []Agent
    recv   chan *types.Block
    mux    *event.TypeMux
    quit   chan struct{}
    pow    pow.PoW
    atWork int64

    eth      core.Backend
    chain    *core.ChainManager
    proc     *core.BlockProcessor
    coinbase common.Address

    current *environment

    uncleMu        sync.Mutex
    possibleUncles map[common.Hash]*types.Block

    mining bool
}

func newWorker(coinbase common.Address, eth core.Backend) *worker {
    return &worker{
        eth:            eth,
        mux:            eth.EventMux(),
        recv:           make(chan *types.Block),
        chain:          eth.ChainManager(),
        proc:           eth.BlockProcessor(),
        possibleUncles: make(map[common.Hash]*types.Block),
        coinbase:       coinbase,
    }
}

func (self *worker) start() {
    self.mining = true

    self.quit = make(chan struct{})

    // spin up agents
    for _, agent := range self.agents {
        agent.Start()
    }

    go self.update()
    go self.wait()
}

func (self *worker) stop() {
    self.mining = false
    atomic.StoreInt64(&self.atWork, 0)

    close(self.quit)
}

func (self *worker) register(agent Agent) {
    self.agents = append(self.agents, agent)
    agent.SetReturnCh(self.recv)
}

func (self *worker) update() {
    events := self.mux.Subscribe(core.ChainHeadEvent{}, core.ChainSideEvent{})

    timer := time.NewTicker(2 * time.Second)

out:
    for {
        select {
        case event := <-events.Chan():
            switch ev := event.(type) {
            case core.ChainHeadEvent:
                self.commitNewWork()
            case core.ChainSideEvent:
                self.uncleMu.Lock()
                self.possibleUncles[ev.Block.Hash()] = ev.Block
                self.uncleMu.Unlock()
            }

        case <-self.quit:
            // stop all agents
            for _, agent := range self.agents {
                agent.Stop()
            }
            break out
        case <-timer.C:
            minerlogger.Infoln("Hash rate:", self.HashRate(), "Khash")

            // XXX In case all mined a possible uncle
            if atomic.LoadInt64(&self.atWork) == 0 {
                self.commitNewWork()
            }
        }
    }

    events.Unsubscribe()
}

func (self *worker) wait() {
    for {
        for block := range self.recv {
            atomic.AddInt64(&self.atWork, -1)

            if block == nil {
                continue
            }

            if err := self.chain.InsertChain(types.Blocks{block}); err == nil {
                for _, uncle := range block.Uncles() {
                    delete(self.possibleUncles, uncle.Hash())
                }
                self.mux.Post(core.NewMinedBlockEvent{block})

                jsonlogger.LogJson(&logger.EthMinerNewBlock{
                    BlockHash:     block.Hash().Hex(),
                    BlockNumber:   block.Number(),
                    ChainHeadHash: block.ParentHeaderHash.Hex(),
                    BlockPrevHash: block.ParentHeaderHash.Hex(),
                })
            } else {
                self.commitNewWork()
            }
        }
    }
}

func (self *worker) push() {
    if self.mining {
        self.current.block.Header().GasUsed = self.current.totalUsedGas
        self.current.block.SetRoot(self.current.state.Root())

        // push new work to agents
        for _, agent := range self.agents {
            atomic.AddInt64(&self.atWork, 1)

            agent.Work() <- self.current.block.Copy()
        }
    }
}

func (self *worker) commitNewWork() {
    self.mu.Lock()
    defer self.mu.Unlock()
    self.uncleMu.Lock()
    defer self.uncleMu.Unlock()

    block := self.chain.NewBlock(self.coinbase)

    self.current = env(block, self.eth)
    for _, ancestor := range self.chain.GetAncestors(block, 7) {
        self.current.family.Add(ancestor.Hash())
    }

    parent := self.chain.GetBlock(self.current.block.ParentHash())
    self.current.coinbase.SetGasPool(core.CalcGasLimit(parent, self.current.block))

    transactions := self.eth.TxPool().GetTransactions()
    sort.Sort(types.TxByNonce{transactions})

    // Keep track of transactions which return errors so they can be removed
    var (
        remove types.Transactions
        tcount = 0
    )
gasLimit:
    for i, tx := range transactions {
        err := self.commitTransaction(tx)
        switch {
        case core.IsNonceErr(err):
            fallthrough
        case core.IsInvalidTxErr(err):
            // Remove invalid transactions
            from, _ := tx.From()
            self.chain.TxState().RemoveNonce(from, tx.Nonce())
            remove = append(remove, tx)
            minerlogger.Infof("TX (%x) failed, will be removed: %v\n", tx.Hash().Bytes()[:4], err)
            minerlogger.Infoln(tx)
        case state.IsGasLimitErr(err):
            minerlogger.Infof("Gas limit reached for block. %d TXs included in this block\n", i)
            // Break on gas limit
            break gasLimit
        default:
            tcount++
        }
    }
    self.eth.TxPool().RemoveSet(remove)

    var (
        uncles    []*types.Header
        badUncles []common.Hash
    )
    for hash, uncle := range self.possibleUncles {
        if len(uncles) == 2 {
            break
        }

        if err := self.commitUncle(uncle.Header()); err != nil {
            minerlogger.Infof("Bad uncle found and will be removed (%x)\n", hash[:4])
            minerlogger.Debugln(uncle)
            badUncles = append(badUncles, hash)
        } else {
            minerlogger.Infof("commiting %x as uncle\n", hash[:4])
            uncles = append(uncles, uncle.Header())
        }
    }
    minerlogger.Infof("commit new work on block %v with %d txs & %d uncles\n", self.current.block.Number(), tcount, len(uncles))
    for _, hash := range badUncles {
        delete(self.possibleUncles, hash)
    }

    self.current.block.SetUncles(uncles)

    self.current.state.AddBalance(self.coinbase, core.BlockReward)

    self.current.state.Update(common.Big0)
    self.push()
}

var (
    inclusionReward = new(big.Int).Div(core.BlockReward, big.NewInt(32))
    _uncleReward    = new(big.Int).Mul(core.BlockReward, big.NewInt(15))
    uncleReward     = new(big.Int).Div(_uncleReward, big.NewInt(16))
)

func (self *worker) commitUncle(uncle *types.Header) error {
    if self.current.uncles.Has(uncle.Hash()) {
        // Error not unique
        return core.UncleError("Uncle not unique")
    }
    self.current.uncles.Add(uncle.Hash())

    if !self.current.family.Has(uncle.ParentHash) {
        return core.UncleError(fmt.Sprintf("Uncle's parent unknown (%x)", uncle.ParentHash[0:4]))
    }

    if self.current.family.Has(uncle.Hash()) {
        return core.UncleError(fmt.Sprintf("Uncle already in family (%x)", uncle.Hash()))
    }

    self.current.state.AddBalance(uncle.Coinbase, uncleReward)
    self.current.state.AddBalance(self.coinbase, inclusionReward)

    return nil
}

func (self *worker) commitTransaction(tx *types.Transaction) error {
    snap := self.current.state.Copy()
    receipt, _, err := self.proc.ApplyTransaction(self.current.coinbase, self.current.state, self.current.block, tx, self.current.totalUsedGas, true)
    if err != nil && (core.IsNonceErr(err) || state.IsGasLimitErr(err) || core.IsInvalidTxErr(err)) {
        self.current.state.Set(snap)
        return err
    }

    self.current.block.AddTransaction(tx)
    self.current.block.AddReceipt(receipt)

    return nil
}

func (self *worker) HashRate() int64 {
    var tot int64
    for _, agent := range self.agents {
        tot += agent.GetHashRate()
    }

    return tot
}