/*******************************************************************************

    Copyright(C) Jonas 'Sortie' Termansen 2012.

    This file is part of Sortix.

    Sortix 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.

    Sortix 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
    Sortix. If not, see <http://www.gnu.org/licenses/>.

    sortix/kernel/kthread.h
    Utility and synchronization mechanisms for kernel threads.

*******************************************************************************/

#ifndef SORTIX_KTHREAD_H
#define SORTIX_KTHREAD_H

#include <stddef.h>

#include <sortix/signal.h>

namespace Sortix {

extern "C" {

inline static void kthread_yield(void) { asm volatile ("int $129"); }
__attribute__((noreturn)) void kthread_exit(void* param = NULL);
typedef unsigned kthread_mutex_t;
const kthread_mutex_t KTHREAD_MUTEX_INITIALIZER = 0;
unsigned kthread_mutex_trylock(kthread_mutex_t* mutex);
void kthread_mutex_lock(kthread_mutex_t* mutex);
unsigned long kthread_mutex_lock_signal(kthread_mutex_t* mutex);
void kthread_mutex_unlock(kthread_mutex_t* mutex);
struct kthread_cond_elem;
typedef struct kthread_cond_elem kthread_cond_elem_t;
struct kthread_cond
{
	kthread_cond_elem_t* first;
	kthread_cond_elem_t* last;
};
typedef struct kthread_cond kthread_cond_t;
const kthread_cond_t KTHREAD_COND_INITIALIZER = { NULL, NULL };
void kthread_cond_wait(kthread_cond_t* cond, kthread_mutex_t* mutex);
unsigned long kthread_cond_wait_signal(kthread_cond_t* cond, kthread_mutex_t* mutex);
void kthread_cond_signal(kthread_cond_t* cond);
void kthread_cond_broadcast(kthread_cond_t* cond);

} // extern "C"

class ScopedLock
{
public:
	ScopedLock(kthread_mutex_t* mutex)
	{
		this->mutex = mutex;
		if ( mutex )
			kthread_mutex_lock(mutex);
	}

	~ScopedLock()
	{
		Reset();
	}

	void Reset()
	{
		if ( mutex )
			kthread_mutex_unlock(mutex);
		mutex = NULL;
	}

private:
	kthread_mutex_t* mutex;

};

class ScopedLockSignal
{
public:
	ScopedLockSignal(kthread_mutex_t* mutex)
	{
		this->mutex = mutex;
		this->acquired = !mutex || kthread_mutex_lock_signal(mutex);
	}

	~ScopedLockSignal()
	{
		Reset();
	}

	void Reset()
	{
		if ( mutex && acquired )
			kthread_mutex_unlock(mutex);
		mutex = NULL;
	}

	bool IsAcquired() { return acquired; }

private:
	kthread_mutex_t* mutex;
	bool acquired;

};

} // namespace Sortix

#endif