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/consensus"
    "github.com/ethereum/go-ethereum/log"
)

type CpuAgent struct {
    mu sync.Mutex

    taskCh        chan *Package
    returnCh      chan<- *Package
    stop          chan struct{}
    quitCurrentOp chan struct{}

    chain  consensus.ChainReader
    engine consensus.Engine

    started int32 // started indicates whether the agent is currently started
}

func NewCpuAgent(chain consensus.ChainReader, engine consensus.Engine) *CpuAgent {
    agent := &CpuAgent{
        chain:  chain,
        engine: engine,
        stop:   make(chan struct{}, 1),
        taskCh: make(chan *Package, 1),
    }
    return agent
}

func (self *CpuAgent) AssignTask(p *Package) {
    if atomic.LoadInt32(&self.started) == 1 {
        self.taskCh <- p
    }
}
func (self *CpuAgent) DeliverTo(ch chan<- *Package) { self.returnCh = ch }

func (self *CpuAgent) Start() {
    if !atomic.CompareAndSwapInt32(&self.started, 0, 1) {
        return // agent already started
    }
    go self.update()
}

func (self *CpuAgent) Stop() {
    if !atomic.CompareAndSwapInt32(&self.started, 1, 0) {
        return // agent already stopped
    }
    self.stop <- struct{}{}
done:
    // Empty work channel
    for {
        select {
        case <-self.taskCh:
        default:
            break done
        }
    }
}

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

func (self *CpuAgent) mine(p *Package, stop <-chan struct{}) {
    var err error
    if p.Block, err = self.engine.Seal(self.chain, p.Block, stop); p.Block != nil {
        log.Info("Successfully sealed new block", "number", p.Block.Number(), "hash", p.Block.Hash())
        self.returnCh <- p
    } else {
        if err != nil {
            log.Warn("Block sealing failed", "err", err)
        }
        self.returnCh <- nil
    }
}