path: root/miner/agent.go

// Copyright 2015 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

import (
    "sync"

    "sync/atomic"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/logger"
    "github.com/ethereum/go-ethereum/logger/glog"
    "github.com/ethereum/go-ethereum/pow"
)

type CpuAgent struct {
    mu sync.Mutex

    workCh        chan *Work
    quit          chan struct{}
    quitCurrentOp chan struct{}
    returnCh      chan<- *Result

    index int
    pow   pow.PoW

    isMining int32 // isMining indicates whether the agent is currently mining
}

func NewCpuAgent(index int, pow pow.PoW) *CpuAgent {
    miner := &CpuAgent{
        pow:   pow,
        index: index,
    }

    return miner
}

func (self *CpuAgent) Work() chan<- *Work            { return self.workCh }
func (self *CpuAgent) Pow() pow.PoW                  { return self.pow }
func (self *CpuAgent) SetReturnCh(ch chan<- *Result) { self.returnCh = ch }

func (self *CpuAgent) Stop() {
    self.mu.Lock()
    defer self.mu.Unlock()

    close(self.quit)
}

func (self *CpuAgent) Start() {
    self.mu.Lock()
    defer self.mu.Unlock()

    if !atomic.CompareAndSwapInt32(&self.isMining, 0, 1) {
        return // agent already started
    }

    self.quit = make(chan struct{})
    // creating current op ch makes sure we're not closing a nil ch
    // later on
    self.workCh = make(chan *Work, 1)

    go self.update()
}

func (self *CpuAgent) update() {
out:
    for {
        select {
        case work := <-self.workCh:
            self.mu.Lock()
            if self.quitCurrentOp != nil {
                close(self.quitCurrentOp)
            }
            self.quitCurrentOp = make(chan struct{})
            go self.mine(work, self.quitCurrentOp)
            self.mu.Unlock()
        case <-self.quit:
            self.mu.Lock()
            if self.quitCurrentOp != nil {
                close(self.quitCurrentOp)
                self.quitCurrentOp = nil
            }
            self.mu.Unlock()
            break out
        }
    }

done:
    // Empty work channel
    for {
        select {
        case <-self.workCh:
        default:
            close(self.workCh)
            break done
        }
    }

    atomic.StoreInt32(&self.isMining, 0)
}

func (self *CpuAgent) mine(work *Work, stop <-chan struct{}) {
    glog.V(logger.Debug).Infof("(re)started agent[%d]. mining...\n", self.index)

    // Mine
    nonce, mixDigest := self.pow.Search(work.Block, stop, self.index)
    if nonce != 0 {
        block := work.Block.WithMiningResult(nonce, common.BytesToHash(mixDigest))
        self.returnCh <- &Result{work, block}
    } else {
        self.returnCh <- nil
    }
}

func (self *CpuAgent) GetHashRate() int64 {
    return self.pow.GetHashrate()
}