176 lines
4.4 KiB
C++
176 lines
4.4 KiB
C++
/* A thread pool that can be used standalone or within a more elaborate module.
|
|
*
|
|
* This file is part of OctaSTD. See COPYING.md for futher information.
|
|
*/
|
|
|
|
#ifndef OSTD_THREAD_POOL_HH
|
|
#define OSTD_THREAD_POOL_HH
|
|
|
|
#include <type_traits>
|
|
#include <functional>
|
|
#include <utility>
|
|
#include <vector>
|
|
#include <queue>
|
|
#include <memory>
|
|
#include <thread>
|
|
#include <future>
|
|
#include <mutex>
|
|
#include <condition_variable>
|
|
|
|
namespace ostd {
|
|
|
|
namespace detail {
|
|
struct tpool_func_base {
|
|
tpool_func_base() {}
|
|
virtual ~tpool_func_base() {}
|
|
virtual void clone(tpool_func_base *func) = 0;
|
|
virtual void call() = 0;
|
|
};
|
|
|
|
template<typename F>
|
|
struct tpool_func_impl: tpool_func_base {
|
|
tpool_func_impl(F &&func): p_func(std::move(func)) {}
|
|
|
|
void clone(tpool_func_base *p) {
|
|
new (p) tpool_func_impl(std::move(p_func));
|
|
}
|
|
|
|
void call() {
|
|
p_func();
|
|
}
|
|
|
|
private:
|
|
F p_func;
|
|
};
|
|
|
|
struct tpool_func {
|
|
tpool_func() = delete;
|
|
tpool_func(tpool_func const &) = delete;
|
|
tpool_func &operator=(tpool_func const &) = delete;
|
|
|
|
tpool_func(tpool_func &&func) {
|
|
if (static_cast<void *>(func.p_func) == &func.p_buf) {
|
|
p_func = reinterpret_cast<tpool_func_base *>(&p_buf);
|
|
func.p_func->clone(p_func);
|
|
} else {
|
|
p_func = func.p_func;
|
|
func.p_func = nullptr;
|
|
}
|
|
}
|
|
|
|
template<typename F>
|
|
tpool_func(F &&func) {
|
|
if (sizeof(F) <= sizeof(p_buf)) {
|
|
p_func = ::new(reinterpret_cast<void *>(&p_buf))
|
|
tpool_func_impl<F>{std::move(func)};
|
|
} else {
|
|
p_func = new tpool_func_impl<F>{std::move(func)};
|
|
}
|
|
}
|
|
|
|
~tpool_func() {
|
|
if (static_cast<void *>(p_func) == &p_buf) {
|
|
p_func->~tpool_func_base();
|
|
} else {
|
|
delete p_func;
|
|
}
|
|
}
|
|
|
|
void operator()() {
|
|
p_func->call();
|
|
}
|
|
private:
|
|
std::aligned_storage_t<
|
|
sizeof(std::packaged_task<void()>) + sizeof(void *)
|
|
> p_buf;
|
|
tpool_func_base *p_func;
|
|
};
|
|
}
|
|
|
|
struct thread_pool {
|
|
void start(size_t size = std::thread::hardware_concurrency()) {
|
|
p_running = true;
|
|
auto tf = [this]() {
|
|
thread_run();
|
|
};
|
|
for (size_t i = 0; i < size; ++i) {
|
|
std::thread tid{tf};
|
|
if (!tid.joinable()) {
|
|
throw std::runtime_error{"thread_pool worker failed"};
|
|
}
|
|
p_thrs.push_back(std::move(tid));
|
|
}
|
|
}
|
|
|
|
~thread_pool() {
|
|
destroy();
|
|
}
|
|
|
|
void destroy() {
|
|
{
|
|
std::lock_guard<std::mutex> l{p_lock};
|
|
if (!p_running) {
|
|
return;
|
|
}
|
|
p_running = false;
|
|
}
|
|
p_cond.notify_all();
|
|
for (auto &tid: p_thrs) {
|
|
tid.join();
|
|
p_cond.notify_all();
|
|
}
|
|
}
|
|
|
|
template<typename F, typename ...A>
|
|
auto push(F &&func, A &&...args) ->
|
|
std::future<std::result_of_t<F(A...)>>
|
|
{
|
|
using R = std::result_of_t<F(A...)>;
|
|
std::packaged_task<R()> t;
|
|
if constexpr(sizeof...(A) == 0) {
|
|
t = std::packaged_task<R()>{std::forward<F>(func)};
|
|
} else {
|
|
t = std::packaged_task<R()>{
|
|
std::bind(std::forward<F>(func), std::forward<A>(args)...)
|
|
};
|
|
}
|
|
auto ret = t.get_future();
|
|
{
|
|
std::lock_guard<std::mutex> l{p_lock};
|
|
if (!p_running) {
|
|
throw std::runtime_error{"push on stopped thread_pool"};
|
|
}
|
|
p_tasks.emplace(std::move(t));
|
|
}
|
|
p_cond.notify_one();
|
|
return ret;
|
|
}
|
|
|
|
private:
|
|
void thread_run() {
|
|
for (;;) {
|
|
std::unique_lock<std::mutex> l{p_lock};
|
|
while (p_running && p_tasks.empty()) {
|
|
p_cond.wait(l);
|
|
}
|
|
if (!p_running && p_tasks.empty()) {
|
|
return;
|
|
}
|
|
auto t{std::move(p_tasks.front())};
|
|
p_tasks.pop();
|
|
l.unlock();
|
|
t();
|
|
}
|
|
}
|
|
|
|
std::condition_variable p_cond;
|
|
std::mutex p_lock;
|
|
std::vector<std::thread> p_thrs;
|
|
std::queue<detail::tpool_func> p_tasks;
|
|
bool p_running = false;
|
|
};
|
|
|
|
} /* namespace ostd */
|
|
|
|
#endif
|