多线程消息处理（支持动态调整线程数）

MultiThreadEx.h

#pragma once
 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
 
using TaskFun = std::function<void(void)>;
 
class CMultiThreadEx {
public:
    CMultiThreadEx();
    ~CMultiThreadEx();
 
    bool start();
 
    void stop();
 
    bool post(const TaskFun& task_fun);
 
private:
    void exec();
    void add_thread();
    void del_thread();
    void del_thread_oper();
private:
 
    std::atomic_bool exist_;
    std::mutex thread_mutex_;
    std::map> threads_;
    std::list threads_need_del_;
    std::atomic<int32_t> thread_num_;
    std::atomic<int32_t> task_num_;
    std::queue tasks_;
    std::mutex task_mutex_;
    std::condition_variable condition_;
 
    int32_t min_thead_num_;
    int32_t max_thead_num_;
    int32_t task_avg_num_;
};

MultiThreadEx.cpp:

#include "MultiThreadEx.h"
#include 
 
CMultiThreadEx::CMultiThreadEx()
    : exist_(false)
    , min_thead_num_(1)
    , max_thead_num_(1024)
    , task_avg_num_(10)
{
}
 
CMultiThreadEx::~CMultiThreadEx() {}
 
bool CMultiThreadEx::start() {
    if (exist_) {
        return false;
    }
 
    exist_ = true;
 
    for (size_t i = 0; i < min_thead_num_; i++)
    {
        add_thread();
    }
 
    return true;
}
 
void CMultiThreadEx::stop() {
    if (!exist_) {
        return;
    }
 
    exist_ = false;
    condition_.notify_all();
 
    for (auto& iter_thread : threads_)
    {
        if (iter_thread.second->joinable()) {
            iter_thread.second->join();
        }
    }
 
    return;
}
 
bool CMultiThreadEx::post(const TaskFun& task_fun) {
    if (!exist_) {
        return false;
    }
 
    {
        std::lock_guard lock(task_mutex_);
        tasks_.push(task_fun);
        ++task_num_;
    }
 
    if (thread_num_ < min_thead_num_
        || task_num_ > thread_num_ * task_avg_num_)
    {
        add_thread();
    }
 
    condition_.notify_one();
    return true;
}
 
void CMultiThreadEx::exec() {
    while (exist_)
    {
        TaskFun task = nullptr;
        del_thread_oper();
 
        {
            std::unique_lock lock(task_mutex_);
            if (tasks_.empty()) {
 
                if (thread_num_ > min_thead_num_) {
 
                    auto ret =condition_.wait_for(lock, std::chrono::milliseconds(1000));
                    if (std::cv_status::timeout == ret)
                    {
                        // 退出线程
                        del_thread();
                        break;
                    }
 
                    if (!exist_) {
                        break;
                    }
 
                }
 
                condition_.wait(lock);
            }
 
            if (!exist_) {
                break;
            }
 
            if (!tasks_.empty())
            {
                task = tasks_.front();
                tasks_.pop();
                --task_num_;
            }
        }
 
        if (nullptr != task) {
            task();
        }
    }
 
    return;
}
 
void CMultiThreadEx::add_thread() {
    std::lock_guard lock(thread_mutex_);
 
    std::shared_ptr sptr_thread =
        std::make_shared(std::thread(std::bind(&CMultiThreadEx::exec, this)));
    threads_.insert(std::make_pair(sptr_thread->get_id(), sptr_thread));
    ++thread_num_;
}
 
void CMultiThreadEx::del_thread(){
    std::lock_guard lock(thread_mutex_);
 
    auto id = std::this_thread::get_id();
    auto iter_thread = threads_.find(id);
 
    if (threads_.end() != iter_thread) {
        threads_need_del_.push_back(id);
        --thread_num_;
    }
}
 
void CMultiThreadEx::del_thread_oper(){
    std::lock_guard lock(thread_mutex_);
 
    if (threads_need_del_.empty())
    {
        return;
    }
 
    for (auto& id : threads_need_del_)
    {
        auto iter_thread = threads_.find(id);
 
        if (threads_.end() != iter_thread){
            if (iter_thread->second->joinable()) {
                iter_thread->second->join();
            }
            threads_.erase(id);
        }
    }
}

main:

#include 
#include "MultiThreadEx.h"
 
int main() {
 
    std::mutex m;
 
    CMultiThreadEx t;
    t.start();
 
    auto fun = [&]()
    {
        std::lock_guard lock(m);
 
        static int count = 0;
        std::cout << "Count: " << ++count << "thread-id: " << std::this_thread::get_id() << std::endl;
        std::this_thread::sleep_for(std::chrono::seconds(1));
    };
 
    for (int i = 0; i < 20; ++i)
    {
        t.post(fun);
        //std::this_thread::sleep_for(std::chrono::microseconds(500));
    }
 
    getchar();
    t.post(fun);
    getchar();
    t.stop();
 
    return 0;
}