Kernel/include_std/mutex

/*
	This file is part of Fennix Kernel.

	Fennix Kernel is free software: you can redistribute it and/or
	modify it under the terms of the GNU General Public License as
	published by the Free Software Foundation, either version 3 of
	the License, or (at your option) any later version.

	Fennix Kernel is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with Fennix Kernel. If not, see <https://www.gnu.org/licenses/>.
*/

#pragma once

#include <types.h>

#include <task.hpp>
#include <atomic>
#include <vector>

namespace std
{
	struct defer_lock_t
	{
		explicit defer_lock_t() = default;
	};

	struct try_to_lock_t
	{
		explicit try_to_lock_t() = default;
	};
	struct adopt_lock_t
	{
		explicit adopt_lock_t() = default;
	};

	/**
	 * A mutex implementation.
	 *
	 * @note The TaskManager must be
	 * initialized before using this class.
	 */
	class mutex
	{
	private:
		atomic_bool Locked = false;
		list<Tasking::TCB *> Waiting;
		Tasking::TCB *Holder = nullptr;

	public:
		void lock();
		bool try_lock();
		void unlock();

		mutex();
		mutex(const mutex &) = delete;
		~mutex();
	};

	template <class Mutex>
	class lock_guard
	{
	private:
		Mutex &mutexRef;

	public:
		explicit lock_guard(Mutex &m)
			: mutexRef(m)
		{
			mutexRef.lock();
		}

		lock_guard(Mutex &m, adopt_lock_t t)
			: mutexRef(m)
		{
			/* Do nothing */
		}

		lock_guard(const lock_guard &) = delete;

		~lock_guard()
		{
			mutexRef.unlock();
		}

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