path: root/miner/miner.go

// Copyright 2014 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

// Package miner implements Ethereum block creation and mining.
package miner

import (
    "fmt"
    "sync/atomic"
    "time"

    "github.com/dexon-foundation/dexon/common"
    "github.com/dexon-foundation/dexon/consensus"
    "github.com/dexon-foundation/dexon/core"
    "github.com/dexon-foundation/dexon/core/state"
    "github.com/dexon-foundation/dexon/core/types"
    "github.com/dexon-foundation/dexon/eth/downloader"
    "github.com/dexon-foundation/dexon/event"
    "github.com/dexon-foundation/dexon/log"
    "github.com/dexon-foundation/dexon/params"
)

// Backend wraps all methods required for mining.
type Backend interface {
    BlockChain() *core.BlockChain
    TxPool() *core.TxPool
}

// Miner creates blocks and searches for proof-of-work values.
type Miner struct {
    mux      *event.TypeMux
    worker   *worker
    coinbase common.Address
    eth      Backend
    engine   consensus.Engine
    exitCh   chan struct{}

    canStart    int32 // can start indicates whether we can start the mining operation
    shouldStart int32 // should start indicates whether we should start after sync
}

func New(eth Backend, config *params.ChainConfig, mux *event.TypeMux, engine consensus.Engine, recommit time.Duration, gasFloor, gasCeil uint64, isLocalBlock func(block *types.Block) bool) *Miner {
    miner := &Miner{
        eth:      eth,
        mux:      mux,
        engine:   engine,
        exitCh:   make(chan struct{}),
        worker:   newWorker(config, engine, eth, mux, recommit, gasFloor, gasCeil, isLocalBlock),
        canStart: 1,
    }
    go miner.update()

    return miner
}

// update keeps track of the downloader events. Please be aware that this is a one shot type of update loop.
// It's entered once and as soon as `Done` or `Failed` has been broadcasted the events are unregistered and
// the loop is exited. This to prevent a major security vuln where external parties can DOS you with blocks
// and halt your mining operation for as long as the DOS continues.
func (self *Miner) update() {
    events := self.mux.Subscribe(downloader.StartEvent{}, downloader.DoneEvent{}, downloader.FailedEvent{})
    defer events.Unsubscribe()

    for {
        select {
        case ev := <-events.Chan():
            if ev == nil {
                return
            }
            switch ev.Data.(type) {
            case downloader.StartEvent:
                atomic.StoreInt32(&self.canStart, 0)
                if self.Mining() {
                    self.Stop()
                    atomic.StoreInt32(&self.shouldStart, 1)
                    log.Info("Mining aborted due to sync")
                }
            case downloader.DoneEvent, downloader.FailedEvent:
                shouldStart := atomic.LoadInt32(&self.shouldStart) == 1

                atomic.StoreInt32(&self.canStart, 1)
                atomic.StoreInt32(&self.shouldStart, 0)
                if shouldStart {
                    self.Start(self.coinbase)
                }
                // stop immediately and ignore all further pending events
                return
            }
        case <-self.exitCh:
            return
        }
    }
}

func (self *Miner) Start(coinbase common.Address) {
    atomic.StoreInt32(&self.shouldStart, 1)
    self.SetEtherbase(coinbase)

    if atomic.LoadInt32(&self.canStart) == 0 {
        log.Info("Network syncing, will start miner afterwards")
        return
    }
    self.worker.start()
}

func (self *Miner) Stop() {
    self.worker.stop()
    atomic.StoreInt32(&self.shouldStart, 0)
}

func (self *Miner) Close() {
    self.worker.close()
    close(self.exitCh)
}

func (self *Miner) Mining() bool {
    return self.worker.isRunning()
}

func (self *Miner) HashRate() uint64 {
    if pow, ok := self.engine.(consensus.PoW); ok {
        return uint64(pow.Hashrate())
    }
    return 0
}

func (self *Miner) SetExtra(extra []byte) error {
    if uint64(len(extra)) > params.MaximumExtraDataSize {
        return fmt.Errorf("Extra exceeds max length. %d > %v", len(extra), params.MaximumExtraDataSize)
    }
    self.worker.setExtra(extra)
    return nil
}

// SetRecommitInterval sets the interval for sealing work resubmitting.
func (self *Miner) SetRecommitInterval(interval time.Duration) {
    self.worker.setRecommitInterval(interval)
}

// Pending returns the currently pending block and associated state.
func (self *Miner) Pending() (*types.Block, *state.StateDB) {
    return self.worker.pending()
}

// PendingBlock returns the currently pending block.
//
// Note, to access both the pending block and the pending state
// simultaneously, please use Pending(), as the pending state can
// change between multiple method calls
func (self *Miner) PendingBlock() *types.Block {
    return self.worker.pendingBlock()
}

func (self *Miner) SetEtherbase(addr common.Address) {
    self.coinbase = addr
    self.worker.setEtherbase(addr)
}