目錄

• 完整代碼
• • TaskPool.cpp
  • TaskPool.h
  • main.cpp

完整代碼

TaskPool.cpp

//
// Created by LENOVO on 2021/10/25.
//#include "TaskPool.h"
#include <functional>std::mutex printMutex;TaskPool::TaskPool() : m_bRunning(false)
{}TaskPool::~TaskPool()
{removeAllTasks();
}void TaskPool::init(int threadNum/*= 5*/)
{if (threadNum <= 0)threadNum = 5;m_bRunning = true;for (int i = 0; i < threadNum; i++) {std::shared_ptr<std::thread> spThread;// 這個bind含義是啥spThread.reset(new std::thread(std::bind(&TaskPool::threadFunc, this)));{std::lock_guard<std::mutex> guard(printMutex);std::cout << "Init a thread, id: "<< spThread->get_id() << std::endl;}m_threads.push_back(spThread);}
}void TaskPool::stop()
{m_bRunning = false;// 通知所有線程，不運行了m_cv.notify_all();// 等待所有線程退出for (auto& it : m_threads) {if (it->joinable())it->join();}
}void TaskPool::addTask(Task *task)
{std::shared_ptr<Task> spTask;spTask.reset(task);{// 將task加入隊列是互斥的std::lock_guard<std::mutex> guard(m_mutexList);m_taskList.push_back(spTask);}{std::lock_guard<std::mutex> guard(printMutex);std::cout << "add a Task, id: " << spTask->getID() << ", thread id is: " << std::this_thread::get_id() << std::endl;}// 通知一個線程的threadFuncm_cv.notify_one();
}void TaskPool::removeAllTasks()
{{// 需要先互斥地將指向taskList的ptr重置，然后將整個taskList資源cleadstd::lock_guard<std::mutex> guard(m_mutexList);for (auto& it : m_taskList) {it.reset();}m_taskList.clear();}
}void TaskPool::threadFunc()
{std::shared_ptr<Task> spTask;while (true) {// 獲取task的過程是互斥的{ // 減少鎖的粒度std::unique_lock<std::mutex> guard(m_mutexList);// 如果任務隊列為空,那么就一直wait，等待線程被喚醒加入到隊列中while (m_taskList.empty()) {if (!m_bRunning)break;// 如果獲得了互斥鎖，但是條件不滿足// wait()會釋放鎖，掛起當前線程// 條件變量發生變化的時候，wait()將環型掛起的線程并獲得鎖m_cv.wait(guard);}if (!m_bRunning)break;// 獲取隊頭taskspTask = m_taskList.front();m_taskList.pop_front();}// 如果隊列為空，則重新進行嘗試獲取if (spTask == NULL)continue;// 否則，執行task任務spTask->doIt();// 完成之后，將指針重置spTask.reset();}std::lock_guard<std::mutex> guard(printMutex);std::cout << "exit thread , threadID:" << std::this_thread::get_id() << std::endl;
}

TaskPool.h

//
// Created by LENOVO on 2021/10/25.
//#ifndef UNTITLED_TASKPOOL_H
#define UNTITLED_TASKPOOL_H#include<thread>
#include<mutex>
#include<condition_variable>
#include<list>
#include<vector>
#include<memory>
#include<iostream>extern std::mutex printMutex;class Task{
private:unsigned int id;
public:Task(unsigned int ID){id = ID;}virtual void doIt(){std::lock_guard<std::mutex> guard(printMutex);std::cout << "handle a task ,TaskID is: "<< id << ", thradID is:" << std::this_thread::get_id() << std::endl;}virtual ~Task(){std::lock_guard<std::mutex> guard(printMutex);std::cout << "a task destructed , TaskID is: "<< id << ", thradID is:" << std::this_thread::get_id() << std::endl;}unsigned int getID(){return id;}
};class TaskPool final{
public:TaskPool();~TaskPool();TaskPool(const TaskPool& rhs) = delete;TaskPool& operator=(const TaskPool& rhs) = delete;public:// 初始化線程void init(int threadNum = 5);// 通知所有線程結束運行，并等待所有線程運行結束void stop();void addTask(Task* task);void removeAllTasks();private:void threadFunc();private:std::list<std::shared_ptr<Task>>            m_taskList;std::mutex                                  m_mutexList;std::condition_variable                     m_cv;bool                                        m_bRunning;std::vector<std::shared_ptr<std::thread>>   m_threads;
};#endif //UNTITLED_TASKPOOL_H

main.cpp

#include<chrono>
#include "TaskPool.h"int main()
{TaskPool threadPool;threadPool.init();Task* task = NULL;for (int i = 0; i < 10; i++) {task = new Task(i);threadPool.addTask(task);}std::this_thread::sleep_for(std::chrono::seconds(5));threadPool.stop();return 0;
}