ObjFW  Artifact [227edc0aad]

Artifact 227edc0aadaba5eca16fd3a11462cc68988ac0e3706bfa80f8d75ddac800306d:

• File src/runtime/class.m — part of check-in [0e35ae63a5] at 2012-04-08 15:03:59 on branch runtime — Return Nil for incomplete classes.

  It's better to handle the class like it does not even exist in case it
  is not completely loaded. Throwing an error there introcudes trouble
  with static instances which try to get the class before initializing the
  static instances, so objc_lookup_class() should never throw an error. (user: js, size: 9246) [annotate] [blame] [check-ins using]

/*
 * 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>
#include <string.h>

#include <assert.h>

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

@protocol BasicClass
+ (void)load;
+ (void)initialize;
@end

static struct objc_hashtable *classes = NULL;

static void
register_class(Class cls)
{
	if (classes == NULL)
		classes = objc_hashtable_alloc(2);

	objc_hashtable_set(classes, cls->name, cls);
}

static void
register_selectors(struct objc_abi_class *cls)
{
	struct objc_abi_method_list *ml;
	unsigned int i;

	for (ml = cls->methodlist; ml != NULL; ml = ml->next)
		for (i = 0; i < ml->count; i++)
			objc_register_selector(
			    (struct objc_abi_selector*)&ml->methods[i]);
}

static BOOL
has_load(struct objc_abi_class *cls)
{
	struct objc_abi_method_list *ml;
	unsigned int i;

	for (ml = cls->methodlist; ml != NULL; ml = ml->next)
		for (i = 0; i < ml->count; i++)
			if (!strcmp(ml->methods[i].name, "load"))
				return YES;

	return NO;
}

void
objc_update_dtable(Class cls)
{
	struct objc_method_list *ml;
	struct objc_category **cats;
	struct objc_sparsearray *dtable;
	unsigned int i;

	if (cls->superclass != Nil)
		dtable = objc_sparsearray_copy(cls->superclass->dtable);
	else
		dtable = objc_sparsearray_new();

	for (ml = cls->methodlist; ml != NULL; ml = ml->next)
		for (i = 0; i < ml->count; i++)
			objc_sparsearray_set(dtable,
			    (uint32_t)ml->methods[i].sel.uid,
			    ml->methods[i].imp);

	if ((cats = objc_categories_for_class(cls)) != NULL) {
		for (i = 0; cats[i] != NULL; i++) {
			unsigned int j;

			ml = (cls->info & OBJC_CLASS_INFO_CLASS ?
			    cats[i]->instance_methods : cats[i]->class_methods);

			for (; ml != NULL; ml = ml->next)
				for (j = 0; j < ml->count; j++)
					objc_sparsearray_set(dtable,
					    (uint32_t)ml->methods[j].sel.uid,
					    ml->methods[j].imp);
		}
	}

	if (cls->dtable != NULL)
		objc_sparsearray_free_when_singlethreaded(cls->dtable);

	cls->dtable = dtable;

	if (cls->subclass_list != NULL)
		for (i = 0; cls->subclass_list[i] != NULL; i++)
			objc_update_dtable(cls->subclass_list[i]);
}

void
objc_register_all_classes(struct objc_abi_symtab *symtab)
{
	size_t i;

	for (i = 0; i < symtab->cls_def_cnt; i++)
		register_class((Class)symtab->defs[i]);

	for (i = 0; i < symtab->cls_def_cnt; i++) {
		struct objc_abi_class *cls;
		BOOL load;

		cls = (struct objc_abi_class*)symtab->defs[i];
		load = has_load(cls->metaclass);

		register_selectors(cls);
		register_selectors(cls->metaclass);

		if (load) {
			/* Sets up the dtable */
			assert(objc_get_class(cls->name) == (Class)cls);

			[(Class)cls load];
		}
	}
}

static void
add_subclass(Class cls)
{
	size_t i;

	if (cls->superclass->subclass_list == NULL) {
		if ((cls->superclass->subclass_list =
		    malloc(2 * sizeof(Class))) == NULL)
			ERROR("Not enough memory for subclass list of "
			    "class %s!", cls->superclass->name);

		cls->superclass->subclass_list[0] = cls;
		cls->superclass->subclass_list[1] = Nil;

		return;
	}

	for (i = 0; cls->superclass->subclass_list[i] != Nil; i++);

	cls->superclass->subclass_list =
	    realloc(cls->superclass->subclass_list, (i + 2) * sizeof(Class));

	if (cls->superclass->subclass_list == NULL)
		ERROR("Not enough memory for subclass list of class %s\n",
		    cls->superclass->name);

	cls->superclass->subclass_list[i] = cls;
	cls->superclass->subclass_list[i + 1] = Nil;
}

inline Class
objc_classname_to_class(const char *name)
{
	Class c;

	if (classes == NULL)
		return Nil;

	objc_global_mutex_lock();
	c = (Class)objc_hashtable_get(classes, name);
	objc_global_mutex_unlock();

	return c;
}

static void
call_initialize(Class cls)
{
	struct objc_method_list *ml;
	SEL initialize;
	unsigned int i;

	initialize = sel_registerName("initialize");

	for (ml = cls->isa->methodlist; ml != NULL; ml = ml->next)
		for (i = 0; i < ml->count; i++)
			if (sel_isEqual(&ml->methods[i].sel, initialize))
				((void(*)(id, SEL))ml->methods[i].imp)(cls,
				    initialize);
}

inline Class
objc_lookup_class(const char *name)
{
	Class cls = objc_classname_to_class(name);
	const char *superclass;

	if (cls == NULL)
		return Nil;

	if (cls->info & OBJC_CLASS_INFO_INITIALIZED)
		return cls;

	objc_global_mutex_lock();

	/*
	 * It's possible that two threads try to get a class at the same time.
	 * Make sure that the thread which held the lock did not already
	 * initialize it.
	 */
	if (cls->info & OBJC_CLASS_INFO_INITIALIZED) {
		objc_global_mutex_unlock();
		return cls;
	}

	if ((superclass = ((struct objc_abi_class*)cls)->superclass) != NULL) {
		if ((cls->superclass = objc_lookup_class(superclass)) == Nil) {
			objc_global_mutex_unlock();
			return Nil;
		}

		cls->isa->superclass = cls->superclass->isa;

		add_subclass(cls);
		add_subclass(cls->isa);
	} else
		cls->isa->superclass = cls;

	objc_update_dtable(cls);
	objc_update_dtable(cls->isa);

	cls->info |= OBJC_CLASS_INFO_INITIALIZED;
	cls->isa->info |= OBJC_CLASS_INFO_INITIALIZED;

	call_initialize(cls);

	objc_global_mutex_unlock();

	return cls;
}

Class
objc_get_class(const char *name)
{
	Class cls;

	if ((cls = objc_lookup_class(name)) == Nil)
		ERROR("Class %s not found!", name);

	return cls;
}

const char*
class_getName(Class cls)
{
	return cls->name;
}

Class
class_getSuperclass(Class cls)
{
	return cls->superclass;
}

BOOL
class_isKindOfClass(Class cls1, Class cls2)
{
	Class iter;

	for (iter = cls1; iter != Nil; iter = iter->superclass)
		if (iter == cls2)
			return YES;

	return NO;
}

unsigned long
class_getInstanceSize(Class cls)
{
	return cls->instance_size;
}

IMP
class_getMethodImplementation(Class cls, SEL sel)
{
	return objc_sparsearray_get(cls->dtable, (uint32_t)sel->uid);
}

const char*
objc_get_type_encoding(Class cls, SEL sel)
{
	struct objc_method_list *ml;
	struct objc_category **cats;
	unsigned int i;

	objc_global_mutex_lock();

	for (ml = cls->methodlist; ml != NULL; ml = ml->next) {
		for (i = 0; i < ml->count; i++) {
			if (ml->methods[i].sel.uid == sel->uid) {
				const char *ret = ml->methods[i].sel.types;
				objc_global_mutex_unlock();
				return ret;
			}
		}
	}

	if ((cats = objc_categories_for_class(cls)) != NULL) {
		for (; *cats != NULL; cats++) {
			for (ml = (*cats)->instance_methods; ml != NULL;
			    ml = ml->next) {
				for (i = 0; i < ml->count; i++) {
					if (ml->methods[i].sel.uid ==
					    sel->uid) {
						const char *ret =
						    ml->methods[i].sel.types;
						objc_global_mutex_unlock();
						return ret;
					}
				}
			}
		}
	}

	objc_global_mutex_unlock();

	return NULL;
}

IMP
class_replaceMethod(Class cls, SEL sel, IMP newimp, const char *types)
{
	struct objc_method_list *ml;
	struct objc_category **cats;
	unsigned int i;
	IMP oldimp;

	objc_global_mutex_lock();

	for (ml = cls->methodlist; ml != NULL; ml = ml->next) {
		for (i = 0; i < ml->count; i++) {
			if (ml->methods[i].sel.uid == sel->uid) {
				oldimp = ml->methods[i].imp;

				ml->methods[i].imp = newimp;
				objc_update_dtable(cls);

				objc_global_mutex_unlock();

				return oldimp;
			}
		}
	}

	if ((cats = objc_categories_for_class(cls)) != NULL) {
		for (; *cats != NULL; cats++) {
			if (cls->info & OBJC_CLASS_INFO_METACLASS)
				ml = (*cats)->class_methods;
			else
				ml = (*cats)->instance_methods;

			for (; ml != NULL; ml = ml->next) {
				for (i = 0; i < ml->count; i++) {
					if (ml->methods[i].sel.uid ==
					    sel->uid) {
						oldimp = ml->methods[i].imp;

						ml->methods[i].imp = newimp;
						objc_update_dtable(cls);

						objc_global_mutex_unlock();

						return oldimp;
					}
				}
			}
		}
	}

	/* FIXME: We need a way to free this at objc_exit() */
	if ((ml = malloc(sizeof(struct objc_method_list))) == NULL)
		ERROR("Not enough memory to replace method!");

	ml->next = cls->methodlist;
	ml->count = 1;
	ml->methods[0].sel.uid = sel->uid;
	ml->methods[0].sel.types = types;
	ml->methods[0].imp = newimp;

	cls->methodlist = ml;

	objc_update_dtable(cls);

	objc_global_mutex_unlock();

	return (IMP)nil;
}

static void
free_class(Class rcls)
{
	struct objc_abi_class *cls = (struct objc_abi_class*)rcls;

	if (!(rcls->info & OBJC_CLASS_INFO_INITIALIZED))
		return;

	if (rcls->subclass_list != NULL) {
		free(rcls->subclass_list);
		rcls->subclass_list = NULL;
	}

	objc_sparsearray_free(rcls->dtable);
	rcls->dtable = NULL;

	if (rcls->superclass != Nil)
		cls->superclass = rcls->superclass->name;
}

void
objc_free_all_classes(void)
{
	uint32_t i;

	if (classes == NULL)
		return;

	for (i = 0; i <= classes->last_idx; i++) {
		if (classes->data[i] != NULL) {
			free_class((Class)classes->data[i]->obj);
			free_class(((Class)classes->data[i]->obj)->isa);
		}
	}

	objc_hashtable_free(classes);
	classes = NULL;
}