channel.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 <condition_variable>
#include <cstddef>
#include <mutex>
 
#include "../core/csexc.h"
 
namespace console {
    template <class T, size_t N>
    class Channel;

    template <class T, size_t N>
    class ChannelIterator {
        Channel<T, N> &channel_; 
        T              cache_;   
 
    public:
        using iterator_category = std::input_iterator_tag;
        using value_type = T;
        using difference_type = std::ptrdiff_t;
        using pointer = T *;
        using reference = T &;
 
        explicit ChannelIterator(Channel<T, N> &channel) : channel_(channel) {}

        T &operator*() {
            channel_ >> cache_;
            return cache_;
        }

        T *operator->() { return &cache_; }

        ChannelIterator &operator++() { return *this; }

        ChannelIterator operator++(int) { return *this; }

        bool operator==(const ChannelIterator &) const {
            return !static_cast<bool>(channel_);
        }

        bool operator!=(const ChannelIterator &) const {
            return static_cast<bool>(channel_);
        }
    };

    template <class T, size_t N = 0>
    class Channel {
        T                       buffer_[N];      
        size_t                  read_index_{0};  
        size_t                  write_index_{0}; 
        mutable std::mutex      mutex_;          
        std::condition_variable r_cv_;           
        std::condition_variable w_cv_;           
        bool                    closed_{false};  
 
    public:
        Channel() = default;

        bool operator<<(const T &value) {
            std::unique_lock<std::mutex> lock(mutex_);
            w_cv_.wait(lock,
                [this] { return write_index_ - read_index_ < N || closed_; });
            if (closed_) return false;
            buffer_[write_index_ % N] = value;
            ++write_index_;
            r_cv_.notify_one();
            return true;
        }

        bool operator<<(T &&value) {
            std::unique_lock<std::mutex> lock(mutex_);
            w_cv_.wait(lock,
                [this] { return write_index_ - read_index_ < N || closed_; });
            if (closed_) return false;
            buffer_[write_index_ % N] = std::move(value);
            ++write_index_;
            r_cv_.notify_one();
            return true;
        }

        bool operator<<=(const T &value) {
            std::unique_lock<std::mutex> lock(mutex_);
            if (closed_ || write_index_ - read_index_ >= N) return false;
            buffer_[write_index_ % N] = value;
            ++write_index_;
            r_cv_.notify_one();
            return true;
        }

        bool operator<<=(T &&value) {
            std::unique_lock<std::mutex> lock(mutex_);
            if (closed_ || write_index_ - read_index_ >= N) return false;
            buffer_[write_index_ % N] = std::move(value);
            ++write_index_;
            r_cv_.notify_one();
            return true;
        }

        bool operator>>(T &value) {
            std::unique_lock<std::mutex> lock(mutex_);
            r_cv_.wait(lock,
                [this] { return write_index_ - read_index_ > 0 || closed_; });
            if (closed_ && write_index_ - read_index_ == 0) return false;
            value = std::move(buffer_[read_index_ % N]);
            ++read_index_;
            w_cv_.notify_one();
            return true;
        }

        bool operator>>=(T &value) {
            std::unique_lock<std::mutex> lock(mutex_);
            if (write_index_ - read_index_ == 0) return false;
            value = std::move(buffer_[read_index_ % N]);
            ++read_index_;
            w_cv_.notify_one();
            return true;
        }

        T operator*() {
            std::unique_lock<std::mutex> lock(mutex_);
            r_cv_.wait(lock,
                [this] { return write_index_ - read_index_ > 0 || closed_; });
            if (closed_ && write_index_ - read_index_ == 0)
                throw AsyncError("Channel has been closed.");
            T value = std::move(buffer_[read_index_ % N]);
            ++read_index_;
            w_cv_.notify_one();
            return value;
        }

        std::unique_ptr<T> operator->() {
            std::unique_lock<std::mutex> lock(mutex_);
            r_cv_.wait(lock,
                [this] { return write_index_ - read_index_ > 0 || closed_; });
            if (closed_ && write_index_ - read_index_ == 0)
                throw AsyncError("Channel has been closed.");
            std::unique_ptr<T> ptr(new T(std::move(buffer_[read_index_ % N])));
            ++read_index_;
            w_cv_.notify_one();
            return ptr;
        }

        explicit operator bool() const {
            std::unique_lock<std::mutex> lock(mutex_);
            return !closed_ || write_index_ - read_index_ > 0;
        }

        friend void close(Channel &channel) {
            std::unique_lock<std::mutex> lock(channel.mutex_);
            channel.closed_ = true;
            channel.r_cv_.notify_all();
            channel.w_cv_.notify_all();
        }

        using iterator = ChannelIterator<T, N>;

        iterator begin() { return iterator(*this); }
        iterator end() { return iterator(*this); }

        Channel(const Channel &) = delete;
        Channel &operator=(const Channel &) = delete;
        Channel(Channel &&) = delete;
        Channel &operator=(Channel &&) = delete;
    };

    template <class T>
    class Channel<T, 0> {
        T                       buffer_;         
        mutable std::mutex      mutex_;          
        std::condition_variable r_cv_;           
        std::condition_variable w_cv_;           
        bool                    empty_  = true;  
        bool                    closed_ = false; 
 
    public:
        Channel() = default;

        bool operator<<(const T &value) {
            std::unique_lock<std::mutex> lock(mutex_);
            w_cv_.wait(lock, [this] { return empty_ || closed_; });
            if (closed_) return false;
            buffer_ = value;
            empty_  = false;
            r_cv_.notify_one();
            return true;
        }

        bool operator<<(T &&value) {
            std::unique_lock<std::mutex> lock(mutex_);
            w_cv_.wait(lock, [this] { return empty_ || closed_; });
            if (closed_) return false;
            buffer_ = std::move(value);
            empty_  = false;
            r_cv_.notify_one();
            return true;
        }

        bool operator>>(T &value) {
            std::unique_lock<std::mutex> lock(mutex_);
            r_cv_.wait(lock, [this] { return !empty_ || closed_; });
            if (closed_ && empty_) return false;
            value  = std::move(buffer_);
            empty_ = true;
            w_cv_.notify_one();
            return true;
        }

        T operator*() {
            std::unique_lock<std::mutex> lock(mutex_);
            r_cv_.wait(lock, [this] { return !empty_ || closed_; });
            if (closed_ && empty_) throw AsyncError("Channel has been closed.");
            T value = std::move(buffer_);
            empty_  = true;
            w_cv_.notify_one();
            return value;
        }

        std::unique_ptr<T> operator->() {
            std::unique_lock<std::mutex> lock(mutex_);
            r_cv_.wait(lock, [this] { return !empty_ || closed_; });
            if (closed_ && empty_) throw AsyncError("Channel has been closed.");
            std::unique_ptr<T> ptr(new T(std::move(buffer_)));
            empty_ = true;
            w_cv_.notify_one();
            return ptr;
        }

        explicit operator bool() const {
            std::unique_lock<std::mutex> lock(mutex_);
            return !closed_ || !empty_;
        }

        friend void close(Channel &channel) {
            std::unique_lock<std::mutex> lock(channel.mutex_);
            channel.closed_ = true;
            channel.r_cv_.notify_all();
            channel.w_cv_.notify_all();
        }

        using iterator = ChannelIterator<T, 0>;

        iterator begin() { return iterator(*this); }
        iterator end() { return iterator(*this); }

        Channel(const Channel &) = delete;
        Channel &operator=(const Channel &) = delete;
        Channel(Channel &&) = delete;
        Channel &operator=(Channel &&) = delete;
    };

    template <class T, size_t N, class F>
    inline F for_each(Channel<T, N> &channel, F &&func) {
        T value;
        while (channel >> value) func(value);
        return std::forward<F>(func);
    }
}