ObjFW  threading.m at [b3dd58a1ae]

File src/runtime/threading.m artifact 7dca0646d4 part of check-in b3dd58a1ae

/*
 * Copyright (c) 2008, 2009, 2010, 2011, 2012
 *   Jonathan Schleifer <js@webkeks.org>
 *
 * All rights reserved.
 *
 * This file is part of ObjFW. It may be distributed under the terms of the
 * Q Public License 1.0, which can be found in the file LICENSE.QPL included in
 * the packaging of this file.
 *
 * Alternatively, it may be distributed under the terms of the GNU General
 * Public License, either version 2 or 3, which can be found in the file
 * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
 * file.
 */

#include "config.h"

#include <stdio.h>
#include <stdlib.h>

#import "runtime.h"
#import "runtime-private.h"

static objc_mutex_t global_mutex;
static int num_threads = 1;
static void **free_queue = NULL;
static size_t free_queue_cnt = 0;

BOOL
objc_mutex_new(objc_mutex_t *mutex)
{
	if (!of_mutex_new(&mutex->mutex ))
		return NO;

	mutex->count = 0;

	return YES;
}

BOOL
objc_mutex_lock(objc_mutex_t *mutex)
{
	if (mutex->count > 0 && of_thread_is_current(mutex->owner)) {
		mutex->count++;
		return YES;
	}

	if (!of_mutex_lock(&mutex->mutex))
		return NO;

	mutex->owner = of_thread_current();
	mutex->count++;

	return YES;
}

BOOL
objc_mutex_unlock(objc_mutex_t *mutex)
{
	if (--mutex->count == 0)
		return of_mutex_unlock(&mutex->mutex);

	return YES;
}

BOOL
objc_mutex_free(objc_mutex_t *mutex)
{
	return of_mutex_free(&mutex->mutex);
}

static void __attribute__((constructor))
objc_global_mutex_new(void)
{
	if (!objc_mutex_new(&global_mutex))
		ERROR("Failed to create global mutex!");
}

void
objc_global_mutex_lock(void)
{
	if (!objc_mutex_lock(&global_mutex))
		ERROR("Failed to lock global mutex!");
}

void
objc_global_mutex_unlock(void)
{
	if (!objc_mutex_unlock(&global_mutex))
		ERROR("Failed to unlock global mutex!");
}

void
objc_global_mutex_free(void)
{
	if (!objc_mutex_free(&global_mutex))
		ERROR("Failed to free global mutex!");
}

void
objc_thread_add(void)
{
	/*
	 * If some class is being initialized, we want to wait for it, thus
	 * we use the global lock instead of atomic operations.
	 */
	objc_global_mutex_lock();
	num_threads++;
	objc_global_mutex_unlock();
}

void
objc_thread_remove(void)
{
	size_t i;

	objc_global_mutex_lock();

	if (free_queue != NULL) {
		for (i = 0; i < free_queue_cnt; i++)
			free(free_queue[i]);

		free(free_queue);

		free_queue = NULL;
		free_queue_cnt = 0;
	}

	num_threads--;
	objc_global_mutex_unlock();
}

void
objc_free_when_singlethreaded(void *ptr)
{
	if (num_threads == 1) {
		free(ptr);
		return;
	}

	if (free_queue == NULL)
		free_queue = malloc(sizeof(void*));
	else
		free_queue = realloc(free_queue, sizeof(void*) *
		    (free_queue_cnt + 1));

	if (free_queue == NULL)
		ERROR("Not enough memory for queue of pointers to free!");

	free_queue[free_queue_cnt++] = ptr;
}