ObjFW  Artifact [8659e5eda9]

Artifact 8659e5eda9fea9aca7237aeec6a92bae3890788a1bc32a8f26377792bff5527d:

• File src/runtime/class.m — part of check-in [fe2cbe0021] at 2018-04-22 16:13:04 on branch trunk — runtime: Define BOOL to be the same as bool

  As we define the ABI, we can just replace BOOL with bool everywhere,
  including in ObjFW itself. For the Apple platforms where BOOL and bool
  are different, this is not a problem as BOOL and bool are passed and
  returned the same way in the ABI.

  This still defines BOOL to bool for compatibility, except on AmigaOS and
  Wii, which both have its own BOOL type. (user: js, size: 19487) [annotate] [blame] [check-ins using]

/*
 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017,
 *               2018
 *   Jonathan Schleifer <js@heap.zone>
 *
 * 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 <limits.h>

#include <assert.h>

#import "ObjFW_RT.h"
#import "private.h"

static struct objc_hashtable *classes = NULL;
static unsigned classes_cnt = 0;
static Class *load_queue = NULL;
static size_t load_queue_cnt = 0;
static struct objc_dtable *empty_dtable = NULL;
static unsigned lookups_till_fast_path = 128;
static struct objc_sparsearray *fast_path = NULL;

static void
register_class(struct objc_abi_class *cls)
{
	if (classes == NULL)
		classes = objc_hashtable_new(
		    objc_hash_string, objc_equal_string, 2);

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

	if (empty_dtable == NULL)
		empty_dtable = objc_dtable_new();

	cls->dtable = empty_dtable;
	cls->metaclass->dtable = empty_dtable;

	if (strcmp(cls->name, "Protocol") != 0)
		classes_cnt++;
}

bool
class_registerAlias_np(Class cls, const char *name)
{
	if (classes == NULL)
		return NO;

	objc_hashtable_set(classes, name, (Class)((uintptr_t)cls | 1));

	return YES;
}

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

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

Class
objc_classname_to_class(const char *name, bool cache)
{
	Class cls;

	if (classes == NULL)
		return Nil;

	/*
	 * Fast path
	 *
	 * Instead of looking up the string in a dictionary, which needs
	 * locking, we use a sparse array to look up the pointer. If
	 * objc_classname_to_class() gets called a lot, it is most likely that
	 * the GCC ABI is used, which always calls into objc_lookup_class(), or
	 * that it is used in a loop by the user. In both cases, it is very
	 * likely that the same string pointer is passed again and again.
	 *
	 * This is not used before objc_classname_to_class() has been called a
	 * certain amount of times, so that no memory is wasted if it is only
	 * used rarely, for example if the ObjFW ABI is used and the user does
	 * not call it in a loop.
	 *
	 * Runtime internal usage does not use the fast path and does not count
	 * as a call into objc_classname_to_class(). The reason for this is
	 * that if the runtime calls into objc_classname_to_class(), it already
	 * has the lock and thus the performance gain would be small, but it
	 * would waste memory.
	 */
	if (cache && fast_path != NULL) {
		cls = objc_sparsearray_get(fast_path, (uintptr_t)name);

		if (cls != Nil)
			return cls;
	}

	objc_global_mutex_lock();

	cls = (Class)((uintptr_t)objc_hashtable_get(classes, name) & ~1);

	if (cache && fast_path == NULL && --lookups_till_fast_path == 0)
		fast_path = objc_sparsearray_new(sizeof(uintptr_t));

	if (cache && fast_path != NULL)
		objc_sparsearray_set(fast_path, (uintptr_t)name, cls);

	objc_global_mutex_unlock();

	return cls;
}

static void
call_method(Class cls, const char *method)
{
	SEL selector = sel_registerName(method);

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

static bool
has_load(Class cls)
{
	SEL selector = sel_registerName("load");

	for (struct objc_method_list *ml = cls->isa->methodlist;
	    ml != NULL; ml = ml->next)
		for (size_t i = 0; i < ml->count; i++)
			if (sel_isEqual((SEL)&ml->methods[i].sel, selector))
				return true;

	return false;
}

static void
call_load(Class cls)
{
	if (cls->info & OBJC_CLASS_INFO_LOADED)
		return;

	if (cls->superclass != Nil)
		call_load(cls->superclass);

	call_method(cls, "load");

	cls->info |= OBJC_CLASS_INFO_LOADED;
}

void
objc_update_dtable(Class cls)
{
	struct objc_method_list *ml;
	struct objc_category **cats;

	if (!(cls->info & OBJC_CLASS_INFO_DTABLE))
		return;

	if (cls->dtable == empty_dtable)
		cls->dtable = objc_dtable_new();

	if (cls->superclass != Nil)
		objc_dtable_copy(cls->dtable, cls->superclass->dtable);

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

	if ((cats = objc_categories_for_class(cls)) != NULL) {
		for (unsigned int i = 0; cats[i] != NULL; i++) {
			ml = (cls->info & OBJC_CLASS_INFO_CLASS ?
			    cats[i]->instance_methods : cats[i]->class_methods);

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

	if (cls->subclass_list != NULL)
		for (Class *iter = cls->subclass_list; *iter != NULL; iter++)
			objc_update_dtable(*iter);
}

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)
			OBJC_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)
		OBJC_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;
}


static void
update_ivar_offsets(Class cls)
{
	if (!(cls->info & OBJC_CLASS_INFO_NEW_ABI))
		return;

	if (cls->instance_size > 0)
		return;

	cls->instance_size = -cls->instance_size;

	if (cls->superclass != Nil) {
		cls->instance_size += cls->superclass->instance_size;

		if (cls->ivars != NULL) {
			for (unsigned int i = 0; i < cls->ivars->count; i++) {
				cls->ivars->ivars[i].offset +=
				    cls->superclass->instance_size;
				*cls->ivar_offsets[i] =
				    cls->ivars->ivars[i].offset;
			}
		}
	} else
		for (unsigned int i = 0; i < cls->ivars->count; i++)
			*cls->ivar_offsets[i] = cls->ivars->ivars[i].offset;
}

static void
setup_class(Class cls)
{
	const char *superclass;

	if (cls->info & OBJC_CLASS_INFO_SETUP)
		return;

	if ((superclass = ((struct objc_abi_class *)cls)->superclass) != NULL) {
		Class super = objc_classname_to_class(superclass, false);

		if (super == Nil)
			return;

		setup_class(super);

		if (!(super->info & OBJC_CLASS_INFO_SETUP))
			return;

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

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

	update_ivar_offsets(cls);

	cls->info |= OBJC_CLASS_INFO_SETUP;
	cls->isa->info |= OBJC_CLASS_INFO_SETUP;
}

static void
initialize_class(Class cls)
{
	if (cls->info & OBJC_CLASS_INFO_INITIALIZED)
		return;

	if (cls->superclass)
		initialize_class(cls->superclass);

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

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

	/*
	 * Set it first to prevent calling it recursively due to message sends
	 * in the initialize method
	 */
	cls->info |= OBJC_CLASS_INFO_INITIALIZED;
	cls->isa->info |= OBJC_CLASS_INFO_INITIALIZED;

	call_method(cls, "initialize");
}

void
objc_initialize_class(Class cls)
{
	if (cls->info & OBJC_CLASS_INFO_INITIALIZED)
		return;

	objc_global_mutex_lock();

	/*
	 * It's possible that two threads try to initialize 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;
	}

	setup_class(cls);

	if (!(cls->info & OBJC_CLASS_INFO_SETUP)) {
		objc_global_mutex_unlock();
		return;
	}

	initialize_class(cls);

	objc_global_mutex_unlock();
}

static void
process_load_queue()
{
	for (size_t i = 0; i < load_queue_cnt; i++) {
		setup_class(load_queue[i]);

		if (load_queue[i]->info & OBJC_CLASS_INFO_SETUP) {
			call_load(load_queue[i]);

			load_queue_cnt--;

			if (load_queue_cnt == 0) {
				free(load_queue);
				load_queue = NULL;
				continue;
			}

			load_queue[i] = load_queue[load_queue_cnt];

			load_queue = realloc(load_queue,
			    sizeof(Class) * load_queue_cnt);

			if (load_queue == NULL)
				OBJC_ERROR("Not enough memory for load queue!");
		}
	}
}

void
objc_register_all_classes(struct objc_abi_symtab *symtab)
{
	for (uint16_t i = 0; i < symtab->cls_def_cnt; i++) {
		struct objc_abi_class *cls =
		    (struct objc_abi_class *)symtab->defs[i];

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

	for (uint16_t i = 0; i < symtab->cls_def_cnt; i++) {
		Class cls = (Class)symtab->defs[i];

		if (has_load(cls)) {
			setup_class(cls);

			if (cls->info & OBJC_CLASS_INFO_SETUP)
				call_load(cls);
			else {
				load_queue = realloc(load_queue,
				    sizeof(Class) * (load_queue_cnt + 1));

				if (load_queue == NULL)
					OBJC_ERROR("Not enough memory for load "
					    "queue!");

				load_queue[load_queue_cnt++] = cls;
			}
		} else
			cls->info |= OBJC_CLASS_INFO_LOADED;
	}

	process_load_queue();
}

Class
objc_allocateClassPair(Class superclass, const char *name, size_t extra_bytes)
{
	struct objc_class *cls, *metaclass;
	Class iter, rootclass = Nil;

	if (extra_bytes > LONG_MAX)
		OBJC_ERROR("extra_bytes out of range!")

	if ((cls = calloc(1, sizeof(*cls))) == NULL ||
	    (metaclass = calloc(1, sizeof(*cls))) == NULL)
		OBJC_ERROR("Not enough memory to allocate class pair for class "
		    "%s!", name)

	cls->isa = metaclass;
	cls->superclass = superclass;
	cls->name = name;
	cls->info = OBJC_CLASS_INFO_CLASS;
	cls->instance_size = (superclass != Nil ?
	    superclass->instance_size : 0) + (long)extra_bytes;

	for (iter = superclass; iter != Nil; iter = iter->superclass)
		rootclass = iter;

	metaclass->isa = (rootclass != Nil ? rootclass->isa : cls);
	metaclass->superclass = (superclass != Nil ? superclass->isa : Nil);
	metaclass->name = name;
	metaclass->info = OBJC_CLASS_INFO_CLASS;
	metaclass->instance_size = (superclass != Nil ?
	    superclass->isa->instance_size : 0) + (long)extra_bytes;

	return cls;
}

void
objc_registerClassPair(Class cls)
{
	objc_global_mutex_lock();

	register_class((struct objc_abi_class *)cls);

	if (cls->superclass != Nil) {
		add_subclass(cls);
		add_subclass(cls->isa);
	}

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

	if (has_load(cls))
		call_load(cls);
	else
		cls->info |= OBJC_CLASS_INFO_LOADED;

	process_load_queue();

	objc_global_mutex_unlock();
}

id
objc_lookUpClass(const char *name)
{
	Class cls;

	if ((cls = objc_classname_to_class(name, true)) == NULL)
		return Nil;

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

	objc_global_mutex_lock();

	setup_class(cls);

	objc_global_mutex_unlock();

	if (!(cls->info & OBJC_CLASS_INFO_SETUP))
		return Nil;

	return cls;
}

id
objc_getClass(const char *name)
{
	return objc_lookUpClass(name);
}

id
objc_getRequiredClass(const char *name)
{
	Class cls;

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

	return cls;
}

Class
objc_lookup_class(const char *name)
{
	return objc_getClass(name);
}

Class
objc_get_class(const char *name)
{
	return objc_getRequiredClass(name);
}

unsigned int
objc_getClassList(Class *buf, unsigned int count)
{
	unsigned int j;
	objc_global_mutex_lock();

	if (buf == NULL)
		return classes_cnt;

	if (classes_cnt < count)
		count = classes_cnt;

	j = 0;
	for (uint32_t i = 0; i < classes->size; i++) {
		void *cls;

		if (j >= count) {
			objc_global_mutex_unlock();
			return j;
		}

		if (classes->data[i] == NULL)
			continue;

		if (strcmp(classes->data[i]->key, "Protocol") == 0)
			continue;

		cls = (Class)classes->data[i]->obj;

		if (cls == Nil || (uintptr_t)cls & 1)
			continue;

		buf[j++] = cls;
	}

	objc_global_mutex_unlock();

	return j;
}

Class *
objc_copyClassList(unsigned int *len)
{
	Class *ret;
	unsigned int count;

	objc_global_mutex_lock();

	if ((ret = malloc((classes_cnt + 1) * sizeof(Class))) == NULL)
		OBJC_ERROR("Failed to allocate memory for class list!");

	count = objc_getClassList(ret, classes_cnt);
	assert(count == classes_cnt);

	ret[count] = Nil;

	if (len != NULL)
		*len = count;

	objc_global_mutex_unlock();

	return ret;
}

bool
class_isMetaClass(Class cls)
{
	if (cls == Nil)
		return false;

	return (cls->info & OBJC_CLASS_INFO_METACLASS);
}

const char *
class_getName(Class cls)
{
	if (cls == Nil)
		return "";

	return cls->name;
}

Class
class_getSuperclass(Class cls)
{
	if (cls == Nil)
		return Nil;

	return cls->superclass;
}

unsigned long
class_getInstanceSize(Class cls)
{
	if (cls == Nil)
		return 0;

	return cls->instance_size;
}

IMP
class_getMethodImplementation(Class cls, SEL sel)
{
	/*
	 * We use a dummy object here so that the normal lookup is used, even
	 * though we don't have an object. Doing so is safe, as objc_msg_lookup
	 * does not access the object, but only its class.
	 *
	 * Just looking it up in the dispatch table could result in returning
	 * NULL instead of the forwarding handler, it would also mean
	 * +[resolveClassMethod:] / +[resolveInstanceMethod:] would not be
	 * called.
	 */
	struct {
		Class isa;
	} dummy;

	if (cls == Nil)
		return NULL;

	dummy.isa = cls;
	return objc_msg_lookup((id)&dummy, sel);
}

IMP
class_getMethodImplementation_stret(Class cls, SEL sel)
{
	/*
	 * Same as above, but use objc_msg_lookup_stret instead, so that the
	 * correct forwarding handler is returned.
	 */
	struct {
		Class isa;
	} dummy;

	if (cls == Nil)
		return NULL;

	dummy.isa = cls;
	return objc_msg_lookup_stret((id)&dummy, sel);
}

static struct objc_method *
get_method(Class cls, SEL sel)
{
	struct objc_method_list *ml;
	struct objc_category **cats;

	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 (unsigned int i = 0; i < ml->count; i++)
					if (sel_isEqual(
					    (SEL)&ml->methods[i].sel, sel))
						return &ml->methods[i];
		}
	}

	for (ml = cls->methodlist; ml != NULL; ml = ml->next)
		for (unsigned int i = 0; i < ml->count; i++)
			if (sel_isEqual((SEL)&ml->methods[i].sel, sel))
				return &ml->methods[i];

	return NULL;
}

static void
add_method(Class cls, SEL sel, IMP imp, const char *types)
{
	struct objc_method_list *ml;

	/* FIXME: We need a way to free this at objc_exit() */
	if ((ml = malloc(sizeof(struct objc_method_list))) == NULL)
		OBJC_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 = imp;

	cls->methodlist = ml;

	objc_update_dtable(cls);
}

const char *
class_getMethodTypeEncoding(Class cls, SEL sel)
{
	struct objc_method *method;

	if (cls == Nil)
		return NULL;

	objc_global_mutex_lock();

	if ((method = get_method(cls, sel)) != NULL) {
		const char *ret = method->sel.types;
		objc_global_mutex_unlock();
		return ret;
	}

	objc_global_mutex_unlock();

	if (cls->superclass != Nil)
		return class_getMethodTypeEncoding(cls->superclass, sel);

	return NULL;
}

bool
class_addMethod(Class cls, SEL sel, IMP imp, const char *types)
{
	bool ret;

	objc_global_mutex_lock();

	if (get_method(cls, sel) == NULL) {
		add_method(cls, sel, imp, types);
		ret = true;
	} else
		ret = false;

	objc_global_mutex_unlock();

	return ret;
}

IMP
class_replaceMethod(Class cls, SEL sel, IMP newimp, const char *types)
{
	struct objc_method *method;
	IMP oldimp;

	objc_global_mutex_lock();

	if ((method = get_method(cls, sel)) != NULL) {
		oldimp = method->imp;
		method->imp = newimp;
		objc_update_dtable(cls);
	} else {
		oldimp = NULL;
		add_method(cls, sel, newimp, types);
	}

	objc_global_mutex_unlock();

	return oldimp;
}

Class
object_getClass(id obj_)
{
	struct objc_object *obj;

	if (obj_ == nil)
		return Nil;

	obj = (struct objc_object *)obj_;

	return obj->isa;
}

Class
object_setClass(id obj_, Class cls)
{
	struct objc_object *obj;
	Class old;

	if (obj_ == nil)
		return Nil;

	obj = (struct objc_object *)obj_;

	old = obj->isa;
	obj->isa = cls;

	return old;
}

const char *
object_getClassName(id obj)
{
	return class_getName(object_getClass(obj));
}

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

	if ((rcls->info & OBJC_CLASS_INFO_SETUP) &&
	    rcls->superclass != Nil &&
	    rcls->superclass->subclass_list != NULL) {
		size_t i = SIZE_MAX, count = 0;
		Class *tmp;

		for (tmp = rcls->superclass->subclass_list;
		    *tmp != Nil; tmp++) {
			if (*tmp == rcls)
				i = count;

			count++;
		}

		if (count > 0 && i < SIZE_MAX) {
			tmp = rcls->superclass->subclass_list;
			tmp[i] = tmp[count - 1];
			tmp[count - 1] = NULL;

			if ((tmp = realloc(rcls->superclass->subclass_list,
			    count * sizeof(Class))) != NULL)
				rcls->superclass->subclass_list = tmp;
		}
	}

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

	if (rcls->dtable != NULL && rcls->dtable != empty_dtable)
		objc_dtable_free(rcls->dtable);

	rcls->dtable = NULL;

	if ((rcls->info & OBJC_CLASS_INFO_SETUP) && rcls->superclass != Nil)
		cls->superclass = rcls->superclass->name;

	rcls->info &= ~OBJC_CLASS_INFO_SETUP;
}

void
objc_unregister_class(Class cls)
{
	while (cls->subclass_list != NULL && cls->subclass_list[0] != Nil)
		objc_unregister_class(cls->subclass_list[0]);

	if (cls->info & OBJC_CLASS_INFO_LOADED)
		call_method(cls, "unload");

	objc_hashtable_delete(classes, cls->name);

	if (strcmp(class_getName(cls), "Protocol") != 0)
		classes_cnt--;

	unregister_class(cls);
	unregister_class(cls->isa);
}

void
objc_unregister_all_classes(void)
{
	if (classes == NULL)
		return;

	for (uint32_t i = 0; i < classes->size; i++) {
		if (classes->data[i] != NULL &&
		    classes->data[i] != &objc_deleted_bucket) {
			void *cls = (Class)classes->data[i]->obj;

			if (cls == Nil || (uintptr_t)cls & 1)
				continue;

			objc_unregister_class(cls);

			/*
			 * The table might have been resized, so go back to the
			 * start again.
			 *
			 * Due to the i++ in the for loop, we need to set it to
			 * UINT32_MAX so that it will get increased at the end
			 * of the loop and thus become 0.
			 */
			i = UINT32_MAX;
		}
	}

	assert(classes_cnt == 0);

	if (empty_dtable != NULL) {
		objc_dtable_free(empty_dtable);
		empty_dtable = NULL;
	}

	objc_sparsearray_free(fast_path);
	fast_path = NULL;

	objc_hashtable_free(classes);
	classes = NULL;
}