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| #pragma once
#include <vector>
#include <string>
#include <thread>
#include <queue>
#include <condition_variable>
#include <functional>
#include <future>
class ThreadPool
{
public:
void DoTask()
{
while (true)
{
std::function<void()> task;
{
std::unique_lock<std::mutex> lock{queue_mutex};
condition.wait(lock,
[this]
{ return stop || !tasks.empty(); });
if (stop && tasks.empty())
{
return;
}
task = std::move(tasks.front());
tasks.pop();
}
task();
}
}
ThreadPool(size_t threads) : stop(false)
{
for (size_t i = 0; i < threads; ++i)
{
workers.emplace_back(std::bind(&ThreadPool::DoTask, this));
}
}
~ThreadPool()
{
{
std::unique_lock<std::mutex> ul{queue_mutex};
stop = true;
}
condition.notify_all();
for (auto &worker : workers)
{
worker.join();
}
}
template <class F, class... Args>
auto enqueue(F &&f, Args &&...args) -> std::future<typename std::result_of<F(Args...)>::type>
{
using return_type = typename std::result_of<F(Args...)>::type;
auto task = std::make_shared<std::packaged_task<return_type()>>(
std::bind(std::forward<F>(f), std::forward<Args>(args)...));
std::future<return_type> res = task->get_future();
{
std::unique_lock<std::mutex> lock{queue_mutex};
if (stop)
{
throw std::runtime_error("enqueue on stopped ThreadPool");
}
tasks.emplace(
[task]()
{
(*task)();
});
}
condition.notify_one();
return res;
}
private:
std::vector<std::thread> workers;
std::queue<std::function<void()>> tasks;
std::mutex queue_mutex;
std::condition_variable condition;
bool stop;
};
|