ObjFW  Check-in [f65ad67272]

 * file.
 */

#include "config.h"

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

#include <sys/types.h>

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

struct lock_s {
	id	    object;
	size_t	    count;
	id	      object;
	int	      count;
	size_t	    recursion;
	of_thread_t thread;
	of_mutex_t  mutex;
};
	of_rmutex_t   rmutex;
	struct lock_s *next;
} *locks = NULL;

static of_mutex_t mutex;
static struct lock_s *locks = NULL;
static ssize_t numLocks = 0;

#define SYNC_ERR(f)							\
	{								\
		fprintf(stderr, "WARNING: %s failed in line %d!\n"	\
		    "WARNING: This might result in a race "		\
		    "condition!\n", f, __LINE__);			\
		return 1;						\
	}

static void __attribute__((constructor))
init(void)
{
	if (!of_mutex_new(&mutex))
		OBJC_ERROR("Failed to create mutex!")
}

int
objc_sync_enter(id object)
{
	ssize_t i;

	struct lock_s *lock;
	if (object == nil)
		return 0;

	if (!of_mutex_lock(&mutex))
		SYNC_ERR("of_mutex_lock(&mutex)");
		OBJC_ERROR("Failed to lock mutex!");

	/* Look if we already have a lock */
	for (i = numLocks - 1; i >= 0; i--) {
		if (locks[i].object == object) {
	for (lock = locks; lock != NULL; lock = lock->next) {
		if (lock->object != object)
			if (of_thread_is_current(locks[i].thread))
				locks[i].recursion++;
			else {
				/* Make sure objc_sync_exit doesn't free it */
				locks[i].count++;
			continue;

				/* Unlock so objc_sync_exit can return */
				if (!of_mutex_unlock(&mutex))
		lock->count++;
					SYNC_ERR("of_mutex_unlock(&mutex)");

				if (!of_mutex_lock(&locks[i].mutex)) {
					of_mutex_unlock(&mutex);
		if (!of_mutex_unlock(&mutex))
					SYNC_ERR(
					    "of_mutex_lock(&locks[i].mutex");
				}

			OBJC_ERROR("Failed to unlock mutex!");
				if (!of_mutex_lock(&mutex))
					SYNC_ERR("of_mutex_lock(&mutex)");

				assert(locks[i].recursion == 0);

		if (!of_rmutex_lock(&lock->rmutex))
				/* Update lock's active thread */
				locks[i].thread = of_thread_current();
			}

			OBJC_ERROR("Failed to lock mutex!");
			if (!of_mutex_unlock(&mutex))
				SYNC_ERR("of_mutex_unlock(&mutex)");

			return 0;
		}
	}

		return 0;
	}

	/* Create a new lock */
	if (locks == NULL) {
		if ((locks = malloc(sizeof(struct lock_s))) == NULL) {
			of_mutex_unlock(&mutex);
	if ((lock = malloc(sizeof(*lock))) == NULL)
		OBJC_ERROR("Failed to allocate memory for mutex!");
			SYNC_ERR("malloc(...)");
		}

	} else {
		struct lock_s *new_locks;

	if (!of_rmutex_new(&lock->rmutex))
		if ((new_locks = realloc(locks, (numLocks + 1) *
		    sizeof(struct lock_s))) == NULL) {
			of_mutex_unlock(&mutex);
			SYNC_ERR("realloc(...)");
		}

		OBJC_ERROR("Failed to create mutex!");
		locks = new_locks;
	}


	locks[numLocks].object = object;
	locks[numLocks].count = 1;
	locks[numLocks].recursion = 0;
	lock->object = object;
	lock->count = 1;
	lock->next = locks;
	locks[numLocks].thread = of_thread_current();

	if (!of_mutex_new(&locks[numLocks].mutex)) {
		of_mutex_unlock(&mutex);
	locks = lock;
		SYNC_ERR("of_mutex_new(&locks[numLocks].mutex");
	}


	if (!of_mutex_lock(&locks[numLocks].mutex)) {
		of_mutex_unlock(&mutex);
		SYNC_ERR("of_mutex_lock(&locks[numLocks].mutex");
	}

	if (!of_mutex_unlock(&mutex))
		OBJC_ERROR("Failed to unlock mutex!");

	if (!of_rmutex_lock(&lock->rmutex))
	numLocks++;

		OBJC_ERROR("Failed to lock mutex!");
	if (!of_mutex_unlock(&mutex))
		SYNC_ERR("of_mutex_unlock(&mutex)");

	return 0;
}

int
objc_sync_exit(id object)
{
	ssize_t i;

	struct lock_s *lock, *last = NULL;
	if (object == nil)
		return 0;

	if (!of_mutex_lock(&mutex))
		SYNC_ERR("of_mutex_lock(&mutex)");
		OBJC_ERROR("Failed to lock mutex!");

	for (i = numLocks - 1; i >= 0; i--) {
		if (locks[i].object == object) {
	for (lock = locks; lock != NULL; lock = lock->next) {
		if (lock->object != object) {
			if (locks[i].recursion > 0 &&
			    of_thread_is_current(locks[i].thread)) {
				locks[i].recursion--;

			last = lock;
				if (!of_mutex_unlock(&mutex))
					SYNC_ERR("of_mutex_unlock(&mutex)");

			continue;
				return 0;
			}
		}

			if (!of_mutex_unlock(&locks[i].mutex)) {
		if (!of_rmutex_unlock(&lock->rmutex))
				of_mutex_unlock(&mutex);
				SYNC_ERR("of_mutex_unlock(&locks[i].mutex)");
			}

			OBJC_ERROR("Failed to unlock mutex!");
			locks[i].count--;

			if (locks[i].count == 0) {
		if (--lock->count == 0) {
				struct lock_s *new_locks = NULL;

				if (!of_mutex_free(&locks[i].mutex)) {
					of_mutex_unlock(&mutex);
					SYNC_ERR(
					    "of_mutex_free(&locks[i].mutex");
				}

			if (!of_rmutex_free(&lock->rmutex))
				OBJC_ERROR("Failed to destroy mutex!");

			if (last != NULL)
				numLocks--;
				locks[i] = locks[numLocks];

				if (numLocks == 0) {
				last->next = lock->next;
			if (locks == lock)
					free(locks);
					new_locks = NULL;
				locks = lock->next;
				} else if ((new_locks = realloc(locks,
				    numLocks * sizeof(struct lock_s))) ==
				    NULL) {
					of_mutex_unlock(&mutex);
					SYNC_ERR("realloc(...)");
				}


			free(lock);
				locks = new_locks;
			}
		}

			if (!of_mutex_unlock(&mutex))
				SYNC_ERR("of_mutex_unlock(&mutex)");
		if (!of_mutex_unlock(&mutex))
			OBJC_ERROR("Failed to unlock mutex!");

			return 0;
		}
	}
		return 0;
	}


	of_mutex_unlock(&mutex);
	SYNC_ERR("objc_sync_exit()");
	OBJC_ERROR("objc_sync_exit() was called for an object not locked!");
}