server/src/task_pool.h
Rama main · réplica de lectura del repositorio original.
/**
* @file src/task_pool.h
* @brief Declarations for the task pool system.
*/
#pragma once
// standard includes
#include <chrono>
#include <deque>
#include <functional>
#include <future>
#include <mutex>
#include <optional>
#include <type_traits>
#include <utility>
#include <vector>
// local includes
#include "move_by_copy.h"
#include "utility.h"
namespace task_pool_util {
class _ImplBase {
public:
// _unique_base_type _this_ptr;
inline virtual ~_ImplBase() = default;
virtual void run() = 0;
};
template<class Function>
class _Impl: public _ImplBase {
Function _func;
public:
_Impl(Function &&f):
_func(std::forward<Function>(f)) {
}
void run() override {
_func();
}
};
class TaskPool {
public:
typedef std::unique_ptr<_ImplBase> __task;
typedef _ImplBase *task_id_t;
typedef std::chrono::steady_clock::time_point __time_point;
template<class R>
class timer_task_t {
public:
task_id_t task_id;
std::future<R> future;
timer_task_t(task_id_t task_id, std::future<R> &future):
task_id {task_id},
future {std::move(future)} {
}
};
protected:
std::deque<__task> _tasks;
std::vector<std::pair<__time_point, __task>> _timer_tasks;
std::mutex _task_mutex;
public:
TaskPool() = default;
TaskPool(TaskPool &&other) noexcept:
_tasks {std::move(other._tasks)},
_timer_tasks {std::move(other._timer_tasks)} {
}
TaskPool &operator=(TaskPool &&other) noexcept {
std::swap(_tasks, other._tasks);
std::swap(_timer_tasks, other._timer_tasks);
return *this;
}
template<class Function, class... Args>
auto push(Function &&newTask, Args &&...args) {
static_assert(std::is_invocable_v<Function, Args &&...>, "arguments don't match the function");
using __return = std::invoke_result_t<Function, Args &&...>;
using task_t = std::packaged_task<__return()>;
auto bind = [task = std::forward<Function>(newTask), tuple_args = std::make_tuple(std::forward<Args>(args)...)]() mutable {
return std::apply(task, std::move(tuple_args));
};
task_t task(std::move(bind));
auto future = task.get_future();
std::lock_guard<std::mutex> lg(_task_mutex);
_tasks.emplace_back(toRunnable(std::move(task)));
return future;
}
void pushDelayed(std::pair<__time_point, __task> &&task) {
std::lock_guard lg(_task_mutex);
auto it = _timer_tasks.cbegin();
for (; it < _timer_tasks.cend(); ++it) {
if (std::get<0>(*it) < task.first) {
break;
}
}
_timer_tasks.emplace(it, task.first, std::move(task.second));
}
/**
* @return An id to potentially delay the task.
*/
template<class Function, class X, class Y, class... Args>
auto pushDelayed(Function &&newTask, std::chrono::duration<X, Y> duration, Args &&...args) {
static_assert(std::is_invocable_v<Function, Args &&...>, "arguments don't match the function");
using __return = std::invoke_result_t<Function, Args &&...>;
using task_t = std::packaged_task<__return()>;
__time_point time_point;
if constexpr (std::is_floating_point_v<X>) {
time_point = std::chrono::steady_clock::now() + std::chrono::duration_cast<std::chrono::nanoseconds>(duration);
} else {
time_point = std::chrono::steady_clock::now() + duration;
}
auto bind = [task = std::forward<Function>(newTask), tuple_args = std::make_tuple(std::forward<Args>(args)...)]() mutable {
return std::apply(task, std::move(tuple_args));
};
task_t task(std::move(bind));
auto future = task.get_future();
auto runnable = toRunnable(std::move(task));
task_id_t task_id = &*runnable;
pushDelayed(std::pair {time_point, std::move(runnable)});
return timer_task_t<__return> {task_id, future};
}
/**
* @param task_id The id of the task to delay.
* @param duration The delay before executing the task.
*/
template<class X, class Y>
void delay(task_id_t task_id, std::chrono::duration<X, Y> duration) {
std::lock_guard<std::mutex> lg(_task_mutex);
auto it = _timer_tasks.begin();
for (; it < _timer_tasks.cend(); ++it) {
const __task &task = std::get<1>(*it);
if (&*task == task_id) {
std::get<0>(*it) = std::chrono::steady_clock::now() + duration;
break;
}
}
if (it == _timer_tasks.cend()) {
return;
}
// smaller time goes to the back
auto prev = it - 1;
while (it > _timer_tasks.cbegin()) {
if (std::get<0>(*it) > std::get<0>(*prev)) {
std::swap(*it, *prev);
}
--prev;
--it;
}
}
bool cancel(task_id_t task_id) {
std::lock_guard lg(_task_mutex);
auto it = _timer_tasks.begin();
for (; it < _timer_tasks.cend(); ++it) {
const __task &task = std::get<1>(*it);
if (&*task == task_id) {
_timer_tasks.erase(it);
return true;
}
}
return false;
}
std::optional<std::pair<__time_point, __task>> pop(task_id_t task_id) {
std::lock_guard lg(_task_mutex);
auto pos = std::find_if(std::begin(_timer_tasks), std::end(_timer_tasks), [&task_id](const auto &t) {
return t.second.get() == task_id;
});
if (pos == std::end(_timer_tasks)) {
return std::nullopt;
}
return std::move(*pos);
}
std::optional<__task> pop() {
std::lock_guard lg(_task_mutex);
if (!_tasks.empty()) {
__task task = std::move(_tasks.front());
_tasks.pop_front();
return task;
}
if (!_timer_tasks.empty() && std::get<0>(_timer_tasks.back()) <= std::chrono::steady_clock::now()) {
__task task = std::move(std::get<1>(_timer_tasks.back()));
_timer_tasks.pop_back();
return task;
}
return std::nullopt;
}
bool ready() {
std::lock_guard<std::mutex> lg(_task_mutex);
return !_tasks.empty() || (!_timer_tasks.empty() && std::get<0>(_timer_tasks.back()) <= std::chrono::steady_clock::now());
}
std::optional<__time_point> next() {
std::lock_guard<std::mutex> lg(_task_mutex);
if (_timer_tasks.empty()) {
return std::nullopt;
}
return std::get<0>(_timer_tasks.back());
}
private:
template<class Function>
std::unique_ptr<_ImplBase> toRunnable(Function &&f) {
return std::make_unique<_Impl<Function>>(std::forward<Function &&>(f));
}
};
} // namespace task_pool_util