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Copy pathThreadPool.hpp
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141 lines (121 loc) · 2.91 KB
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#pragma once
#include <vector>
#include <queue>
#include <memory>
#include <thread>
#include <mutex>
#include <condition_variable>
#include <future>
#include <functional>
#include <stdexcept>
#include <map>
#include <type_traits>
#include <iostream>
class ThreadPool
{
public:
ThreadPool(size_t);
template<class F, class... Args>
auto enqueue(F&& f, Args&&... args)
-> std::future<typename std::invoke_result<F, Args...>::type>;
~ThreadPool();
int thread_number(std::thread::id id)
{
if(id_map.find(id) != id_map.end())
return (int)id_map[id];
return -1;
}
size_t num_threads()
{
return num_threads_;
}
static ThreadPool* get()
{
return instance(0);
}
static ThreadPool* instance(uint32_t numthreads)
{
std::unique_lock<std::mutex> lock(singleton_mutex);
if(!singleton) {
singleton = new ThreadPool(numthreads ? numthreads : hardware_concurrency());
}
return singleton;
}
static void release()
{
std::unique_lock<std::mutex> lock(singleton_mutex);
delete singleton;
singleton = nullptr;
}
static uint32_t hardware_concurrency()
{
return std::thread::hardware_concurrency();
}
private:
std::vector<std::thread> workers;
std::queue<std::function<void()>> tasks;
std::mutex queue_mutex;
std::condition_variable condition;
bool stop;
std::map<std::thread::id, size_t> id_map;
size_t num_threads_;
static ThreadPool* singleton;
static std::mutex singleton_mutex;
};
inline ThreadPool::ThreadPool(size_t threads) : stop(false), num_threads_(threads)
{
if(threads == 1)
return;
for(size_t i = 0; i < threads; ++i)
workers.emplace_back([this] {
for(;;)
{
std::function<void()> task;
{
std::unique_lock<std::mutex> lock(this->queue_mutex);
this->condition.wait(lock,
[this] { return this->stop || !this->tasks.empty(); });
if(this->stop && this->tasks.empty())
return;
task = std::move(this->tasks.front());
this->tasks.pop();
}
task();
}
});
size_t thread_count = 0;
for(std::thread& worker : workers)
{
id_map[worker.get_id()] = thread_count;
thread_count++;
}
}
// add new work item to the pool
template<class F, class... Args>
auto ThreadPool::enqueue(F&& f, Args&&... args)
-> std::future<typename std::invoke_result<F, Args...>::type>
{
assert(num_threads_ > 1);
using return_type = typename std::invoke_result<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;
}
inline ThreadPool::~ThreadPool()
{
{
std::unique_lock<std::mutex> lock(queue_mutex);
stop = true;
}
condition.notify_all();
for(std::thread& worker : workers)
worker.join();
}