#ifndef ILOVERS_THREAD_POOL_H
#define ILOVERS_THREAD_POOL_H
#include <iostream>
#include <functional>
#include <thread>
#include <condition_variable>
#include <future>
#include <atomic>
#include <vector>
#include <queue>
// 命名空间
namespace ilovers {
class TaskExecutor;
}
class ilovers::TaskExecutor{
using Task = std::function<void()>;
private:
// 线程池
std::vector<std::thread> pool;
// 任务队列
std::queue<Task> tasks;
// 同步
std::mutex m_task;
std::condition_variable cv_task;
// 是否关闭提交
std::atomic<bool> stop;
public:
// 构造
TaskExecutor(size_t size = 4): stop {false}{
size = size < 1 ? 1 : size;
for(size_t i = 0; i< size; ++i){
pool.emplace_back(&TaskExecutor::schedual, this); // push_back(std::thread{...})
}
}
// 析构
~TaskExecutor(){
for(std::thread& thread : pool){
thread.detach(); // 让线程“自生自灭”
//(); // 等待任务结束， 前提：线程一定会执行完
}
}
// 停止任务提交
void shutdown(){
this->stop.store(true);
}
// 重启任务提交
void restart(){
this->stop.store(false);
}
// 提交一个任务
template<class F, class... Args>
auto commit(F&& f, Args&&... args) ->std::future<decltype(f(args...))> {
if(stop.load()){ // stop == true ??
throw std::runtime_error("task executor have closed commit.");
}
using ResType = decltype(f(args...)); // typename std::result_of<F(Args...)>::type, 函数 f 的返回值类型
auto task = std::make_shared<std::packaged_task<ResType()>>(
std::bind(std::forward<F>(f), std::forward<Args>(args)...)
); // wtf !
{ // 添加任务到队列
std::lock_guard<std::mutex> lock {m_task};
tasks.emplace([task](){ // push(Task{...})
(*task)();
});
}
cv_task.notify_all(); // 唤醒线程执行
std::future<ResType> future = task->get_future();
return future;
}
private:
// 获取一个待执行的 task
Task get_one_task(){
std::unique_lock<std::mutex> lock {m_task};
cv_task.wait(lock, [this](){ return !tasks.empty(); }); // wait 直到有 task
Task task {std::move(tasks.front())}; // 取一个 task
tasks.pop();
return task;
}
// 任务调度
void schedual(){
while(true){
if(Task task = get_one_task()){
task(); //
}else{
// return; // done
}
}
}
};
#endif
void f()
{
std::cout << "hello, f !" << std::endl;
}
struct G{
int operator()(){
std::cout << "hello, g !" << std::endl;
return 42;
}
};
int main()
try{
ilovers::TaskExecutor executor {10};
std::future<void> ff = executor.commit(f);
std::future<int> fg = executor.commit(G{});
std::future<std::string> fh = executor.commit([]()->std::string { std::cout << "hello, h !" << std::endl; return "hello,fh !";});
executor.shutdown();
ff.get();
std::cout << fg.get() << " " << fh.get() << std::endl;
std::this_thread::sleep_for(std::chrono::seconds(5));
executor.restart(); // 重启任务
executor.commit(f).get(); //
std::cout << "end..." << std::endl;
return 0;
}catch(std::exception& e){
std::cout << "some unhappy happened... " << e.what() << std::endl;
}