function_fifo.hpp

// Copyright Take Vos 2022.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
 
#pragma once
 
#include "wfree_fifo.hpp"
#include "functional.hpp"
#include <future>
 
namespace hi::inline v1 {
 
template<typename Proto = void(), std::size_t SlotSize = 64>
class function_fifo {
public:
    constexpr function_fifo() noexcept = default;
    function_fifo(function_fifo const&) = delete;
    function_fifo(function_fifo&&) = delete;
    function_fifo& operator=(function_fifo const&) = delete;
    function_fifo& operator=(function_fifo&&) = delete;
 
    [[nodiscard]] bool empty() const noexcept
    {
        return _fifo.empty();
    }
 
    template<typename... Args>
    auto run_one(Args&&...args) noexcept
    {
        return _fifo.take_one([&args...](auto& item) {
            return item(hi_forward(args)...);
        });
    }
 
    void run_all() noexcept
    {
        while (run_one()) {}
    }
 
    template<typename Func>
    void add_function(Func&& func) noexcept
    {
        _fifo.insert(make_function<Proto>(std::forward<Func>(func)));
    }
 
    template<typename Func, typename... Args>
    auto add_async_function(Func&& func, Args&&...args) noexcept
        requires(std::is_invocable_v<std::decay_t<Func>, std::decay_t<Args>...>)
    {
        return _fifo.insert_and_invoke(
            [](auto& item) {
                return item.get_future();
            },
            make_function<Proto>(std::forward<Func>(func)));
    }
 
private : wfree_fifo<function<Proto>, SlotSize> _fifo;
};
 
} // namespace hi::inline v1