/*
 * Copyright (C) 2008-2009 Tobias Brunner
 * Copyright (C) 2008 Martin Willi
 * Hochschule fuer Technik Rapperswil
 *
 * This program 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 2 of the License, or (at your
 * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
 *
 * This program 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.
 */

#define _GNU_SOURCE
#include <pthread.h>

#include <threading.h>
#include <library.h>
#include <debug.h>

#include "mutex.h"
#include "lock_profiler.h"

/**
 * Implementation of mutex_t.lock.
 */
static void lock(private_mutex_t *this)
{
	int err;

	profiler_start(&this->profile);
	err = pthread_mutex_lock(&this->mutex);
	if (err)
	{
		DBG1("!!! MUTEX LOCK ERROR: %s !!!", strerror(err));
	}
	profiler_end(&this->profile);
}

/**
 * Implementation of mutex_t.unlock.
 */
static void unlock(private_mutex_t *this)
{
	int err;

	err = pthread_mutex_unlock(&this->mutex);
	if (err)
	{
		DBG1("!!! MUTEX UNLOCK ERROR: %s !!!", strerror(err));
	}
}

/**
 * Implementation of mutex_t.lock.
 */
static void lock_r(private_r_mutex_t *this)
{
	pthread_t self = pthread_self();

	if (this->thread == self)
	{
		uintptr_t times;

		/* times++ */
		times = (uintptr_t)pthread_getspecific(this->times);
		pthread_setspecific(this->times, (void*)times + 1);
	}
	else
	{
		lock(&this->generic);
		this->thread = self;
		/* times = 1 */
		pthread_setspecific(this->times, (void*)1);
	}
}

/**
 * Implementation of mutex_t.unlock.
 */
static void unlock_r(private_r_mutex_t *this)
{
	uintptr_t times;

	/* times-- */
	times = (uintptr_t)pthread_getspecific(this->times);
	pthread_setspecific(this->times, (void*)--times);

	if (times == 0)
	{
		this->thread = 0;
		unlock(&this->generic);
	}
}

/**
 * Implementation of mutex_t.destroy
 */
static void mutex_destroy(private_mutex_t *this)
{
	profiler_cleanup(&this->profile);
	pthread_mutex_destroy(&this->mutex);
	free(this);
}

/**
 * Implementation of mutex_t.destroy for recursive mutex'
 */
static void mutex_destroy_r(private_r_mutex_t *this)
{
	profiler_cleanup(&this->generic.profile);
	pthread_mutex_destroy(&this->generic.mutex);
	pthread_key_delete(this->times);
	free(this);
}

/*
 * see header file
 */
mutex_t *mutex_create(mutex_type_t type)
{
	switch (type)
	{
		case MUTEX_TYPE_RECURSIVE:
		{
			private_r_mutex_t *this = malloc_thing(private_r_mutex_t);

			this->generic.public.lock = (void(*)(mutex_t*))lock_r;
			this->generic.public.unlock = (void(*)(mutex_t*))unlock_r;
			this->generic.public.destroy = (void(*)(mutex_t*))mutex_destroy_r;

			pthread_mutex_init(&this->generic.mutex, NULL);
			pthread_key_create(&this->times, NULL);
			this->generic.recursive = TRUE;
			profiler_init(&this->generic.profile);
			this->thread = 0;

			return &this->generic.public;
		}
		case MUTEX_TYPE_DEFAULT:
		default:
		{
			private_mutex_t *this = malloc_thing(private_mutex_t);

			this->public.lock = (void(*)(mutex_t*))lock;
			this->public.unlock = (void(*)(mutex_t*))unlock;
			this->public.destroy = (void(*)(mutex_t*))mutex_destroy;

			pthread_mutex_init(&this->mutex, NULL);
			this->recursive = FALSE;
			profiler_init(&this->profile);

			return &this->public;
		}
	}
}