Linux：简易进程池

ProcessPool.hpp

#ifndef __PROCESS_POOL_HPP__
#define __PROCESS_POOL_HPP__

#include 
#include 
#include 
#include 
#include 
#include "Task.hpp"

class Channel
{
public:
    Channel(int fd, pid_t id) : _wfd(fd), _subid(id)
    {
        _name = "channel-" + std::to_string(_wfd) + "-" + std::to_string(_subid);
    }
    ~Channel()
    {
    }
    void Send(int code)
    {
        int n = write(_wfd, &code, sizeof(code));
        (void)n; 
    }
    void Close()
    {
        close(_wfd);
    }
    void Wait()
    {
        pid_t rid = waitpid(_subid, nullptr, 0);
        (void)rid;
    }
    int Fd() { return _wfd; }
    pid_t SubId() { return _subid; }
    std::string Name() { return _name; }

private:
    int _wfd;
    pid_t _subid;
    std::string _name;
};

class ChannelManager
{
public:
    ChannelManager() : _next(0)
    {
    }
    void Insert(int wfd, pid_t subid)
    {
        _channels.emplace_back(wfd, subid);
        // Channel c(wfd, subid);
        // _channels.push_back(std::move(c));
    }
    Channel &Select()
    {
        auto &c = _channels[_next];
        _next++;
        _next %= _channels.size();
        return c;
    }
    void PrintChannel()
    {
        for (auto &channel : _channels)
        {
            std::cout << channel.Name() << std::endl;
        }
    }
    void StopSubProcess()
    {
        for (auto &channel : _channels)
        {
            channel.Close();
            std::cout << "关闭: " << channel.Name() << std::endl;
        }
    }
    void WaitSubProcess()
    {
        for (auto &channel : _channels)
        {
            channel.Wait();
            std::cout << "回收: " << channel.Name() << std::endl;
        }
    }
    ~ChannelManager() {}

private:
    std::vector _channels;
    int _next;
};

const int gdefaultnum = 5;

class ProcessPool
{
public:
    ProcessPool(int num) : _process_num(num)
    {
        _tm.Register(PrintLog);
        _tm.Register(Download);
        _tm.Register(Upload);
    }
    void Work(int rfd)
    {
        while (true)
        {
            int code = 0;
            ssize_t n = read(rfd, &code, sizeof(code));
            if (n > 0)
            {
                if (n != sizeof(code))
                {
                    continue;
                }
                std::cout << "子进程[" << getpid() << "]收到一个任务码: " << code << std::endl;
                _tm.Execute(code);
            }
            else if (n == 0)
            {
                std::cout << "子进程退出" << std::endl;
                break;
            }
            else
            {
                std::cout << "读取错误" << std::endl;
                break;
            }
        }
    }
    bool Start()
    {
        for (int i = 0; i < _process_num; i++)
        {
            // 1. 创建管道
            int pipefd[2] = {0};
            int n = pipe(pipefd);
            if (n < 0)
                return false;

            // 2. 创建子进程
            pid_t subid = fork();
            if (subid < 0)
                return false;
            else if (subid == 0)
            {
                // 子进程
                // 3. 关闭不需要的文件描述符
                close(pipefd[1]);
                Work(pipefd[0]); //??
                close(pipefd[0]);
                exit(0);
            }
            else
            {
                // 父进程
                //  3. 关闭不需要的文件描述符
                close(pipefd[0]); // 写端：pipefd[1];
                _cm.Insert(pipefd[1], subid);
                // wfd, subid
            }
        }
        return true;
    }
    void Debug()
    {
        _cm.PrintChannel();
    }
    void Run()
    {
        // 1. 选择一个任务
        int taskcode = _tm.Code();

        // 2. 选择一个信道[子进程],负载均衡的选择一个子进程，完成任务
        auto &c = _cm.Select();
        std::cout << "选择了一个子进程: " << c.Name() << std::endl;
        // 3. 发送任务
        c.Send(taskcode);
        std::cout << "发送了一个任务码: " << taskcode << std::endl;
    }
    void Stop()
    {
        // 关闭父进程所有的wfd即可
        _cm.StopSubProcess();
        // 回收所有子进程
        _cm.WaitSubProcess();
    }
    ~ProcessPool()
    {
    }

private:
    ChannelManager _cm;
    int _process_num;
    TaskManager _tm;
};

#endif

Task.hpp 

#pragma once

#include 
#include 
#include 

typedef void (*task_t)();

debug/
void PrintLog()
{
    std::cout << "我是一个打印日志的任务" << std::endl;
}

void Download()
{
    std::cout << "我是一个下载的任务" << std::endl;
}

void Upload()
{
    std::cout << "我是一个上传的任务" << std::endl;
}
//

class TaskManager
{
public:
    TaskManager()
    {
        srand(time(nullptr));
    }
    void Register(task_t t)
    {
        _tasks.push_back(t);
    }
    int Code()
    {
        return rand() % _tasks.size();
    }
    void Execute(int code)
    {
        if(code >= 0 && code < _tasks.size())
        {
            _tasks[code]();
        }
    }
    ~TaskManager()
    {}
private:
    std::vector _tasks;
};

 Main.cc

#include "ProcessPool.hpp"

int main()
{
    // 这个代码，有一个藏得比较深的bug --- TODO
    // 创建进程池对象
    ProcessPool pp(gdefaultnum);

    // 启动进程池
    pp.Start();

    // 自动派发任务
    int cnt = 10;
    while(cnt--)
    {
        pp.Run();
        sleep(1);
    }

    // 回收，结束进程池
    pp.Stop();
    return 0;
}