task.h

Go to the documentation of this file.

 
/*
Copyright (c) 2026 MrXie1109
 
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
 
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
 
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
 
#pragma once
#include <functional>
#include <future>
#include <memory>
#include <thread>
 
#include "../core/sfinae.h"
#include "./event.h"
 
namespace console {
    template <class T>
    class Task {
        std::future<T>         future_; 
        std::thread            thread_; 
        std::unique_ptr<Event> event_;  
 
    public:
        Task() = default;

        template <class F, class... Args>
        explicit Task(F &&f, Args &&...args) {
            start(std::forward<F>(f), std::forward<Args>(args)...);
        }

        Task(const Task &) = delete;
        Task &operator=(const Task &) = delete;

        Task(Task &&other) noexcept :
            future_(std::move(other.future_)),
            thread_(std::move(other.thread_)), //
            event_(std::move(other.event_)) {}

        Task &operator=(Task &&other) noexcept {
            if (this != &other) {
                if (event_) event_->set();
                if (thread_.joinable()) thread_.join();
                future_ = std::move(other.future_);
                thread_ = std::move(other.thread_);
                event_  = std::move(other.event_);
            }
            return *this;
        }

        ~Task() {
            if (event_) event_->set();
            if (thread_.joinable()) thread_.join();
        }

        template <class F, class... Args>
        typename std::enable_if<
            !is_callable<F, const Event &, Args...>::value>::type
        start(F &&f, Args &&...args) {
            auto bound_task
                = std::bind(std::forward<F>(f), std::forward<Args>(args)...);
            std::packaged_task<T()> task(std::move(bound_task));
            future_ = task.get_future();
            thread_ = std::thread(std::move(task));
        }
 
        template <class F, class... Args>
        typename std::enable_if<
            is_callable<F, const Event &, Args...>::value>::type
        start(F &&f, Args &&...args) {
            if (!event_) event_.reset(new Event());
            start(std::forward<F>(f),
                std::cref(*event_),
                std::forward<Args>(args)...);
        }

        T get() { return future_.get(); }

        bool valid() { return future_.valid(); }

        void wait() const { future_.wait(); }

        template <class Rep, class Period>
        std::future_status
        wait_for(const std::chrono::duration<Rep, Period> &timeout) const {
            return future_.wait_for(timeout);
        }

        std::future_status wait_for(Time timeout) const {
            return future_.wait_for(std::chrono::nanoseconds(timeout.count()));
        }

        std::future_status wait_for(double seconds) const {
            return future_.wait_for(std::chrono::duration<double>(seconds));
        }

        template <class Clock, class Duration>
        std::future_status wait_until(
            const std::chrono::time_point<Clock, Duration> &time_point) const {
            return future_.wait_until(time_point);
        }

        std::future_status status() const {
            return future_.wait_for(std::chrono::nanoseconds(0));
        }

        void cancel() {
            if (status() == std::future_status::ready) return;
            if (event_) event_->set();
            std::promise<T> promise;
            future_ = promise.get_future();
            promise.set_exception(std::make_exception_ptr(
                AsyncError("Task has been cancelled.")));
        }
    };

    template <class T>
    class SharedTask {
        std::shared_future<T>           future_; 
        std::shared_ptr<std::thread>    thread_; 
        std::shared_ptr<Event>          event_;  
        std::shared_ptr<std::once_flag> flag_;   

        static void thread_deleter(std::thread *t) {
            if (t && t->joinable()) t->join();
        }

        static void event_deleter(Event *e) { e->set(); }
 
    public:
        SharedTask() : flag_(new std::once_flag()) {}

        template <class F,
            class... Args,
            class = typename std::enable_if<
                is_callable<F, Args...>::value
                || is_callable<F, const Event &, Args...>::value>::type>
        explicit SharedTask(F &&f, Args &&...args) :
            flag_(new std::once_flag()) {
            start(std::forward<F>(f), std::forward<Args>(args)...);
        }

        SharedTask(const SharedTask &other) :
            future_(other.future_), //
            thread_(other.thread_), //
            event_(other.event_),   //
            flag_(other.flag_) {}

        SharedTask &operator=(const SharedTask &other) {
            future_ = other.future_;
            thread_ = other.thread_;
            event_  = other.event_;
            flag_   = other.flag_;
            return *this;
        }

        SharedTask(SharedTask &&other) noexcept :
            future_(std::move(other.future_)),
            thread_(std::move(other.thread_)), //
            event_(std::move(other.event_)),   //
            flag_(std::move(other.flag_)) {}

        SharedTask &operator=(SharedTask &&other) noexcept {
            if (this != &other) {
                future_ = std::move(other.future_);
                thread_ = std::move(other.thread_);
                event_  = std::move(other.event_);
                flag_   = std::move(other.flag_);
            }
            return *this;
        }

        ~SharedTask() = default;

        template <class F, class... Args>
        typename std::enable_if<
            !is_callable<F, const Event &, Args...>::value>::type
        start(F &&f, Args &&...args) {
            auto bound_task
                = std::bind(std::forward<F>(f), std::forward<Args>(args)...);
            std::packaged_task<T()> task(std::move(bound_task));
            future_ = task.get_future().share();
            thread_ = std::shared_ptr<std::thread>(
                new std::thread(std::move(task)), thread_deleter);
        }
 
        template <class F, class... Args>
        typename std::enable_if<
            is_callable<F, const Event &, Args...>::value>::type
        start(F &&f, Args &&...args) {
            if (!event_)
                event_ = std::shared_ptr<Event>(new Event(), event_deleter);
            start(std::forward<F>(f),
                std::cref(*event_),
                std::forward<Args>(args)...);
        }

        T get() { return future_.get(); }

        bool valid() { return future_.valid(); }

        void wait() const { future_.wait(); }

        template <class Rep, class Period>
        std::future_status
        wait_for(const std::chrono::duration<Rep, Period> &timeout) const {
            return future_.wait_for(timeout);
        }

        std::future_status wait_for(Time timeout) const {
            return future_.wait_for(std::chrono::nanoseconds(timeout.count()));
        }

        std::future_status wait_for(double seconds) const {
            return future_.wait_for(std::chrono::duration<double>(seconds));
        }

        template <class Clock, class Duration>
        std::future_status wait_until(
            const std::chrono::time_point<Clock, Duration> &time_point) const {
            return future_.wait_until(time_point);
        }

        std::future_status status() const {
            return future_.wait_for(std::chrono::nanoseconds(0));
        }

        void cancel() {
            std::call_once(*flag_, [this] {
                if (status() == std::future_status::ready) return;
                if (event_) event_->set();
                std::promise<T> promise;
                future_ = promise.get_future().share();
                promise.set_exception(std::make_exception_ptr(
                    AsyncError("SharedTask has been cancelled.")));
            });
        }
    };
}