/*
* Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017,
* 2018, 2019
* 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>
#import "ObjFW_RT.h"
#import "private.h"
static struct objc_hashtable *classes = NULL;
static unsigned classesCount = 0;
static Class *loadQueue = NULL;
static size_t loadQueueCount = 0;
static struct objc_dtable *emptyDTable = NULL;
static unsigned lookupsUntilFastPath = 128;
static struct objc_sparsearray *fastPath = NULL;
static void
registerClass(struct objc_abi_class *rawClass)
{
if (classes == NULL)
classes = objc_hashtable_new(
objc_hash_string, objc_equal_string, 2);
objc_hashtable_set(classes, rawClass->name, rawClass);
if (emptyDTable == NULL)
emptyDTable = objc_dtable_new();
rawClass->DTable = emptyDTable;
rawClass->metaclass->DTable = emptyDTable;
if (strcmp(rawClass->name, "Protocol") != 0)
classesCount++;
}
bool
class_registerAlias_np(Class class, const char *name)
{
objc_global_mutex_lock();
if (classes == NULL) {
objc_global_mutex_unlock();
return NO;
}
objc_hashtable_set(classes, name, (Class)((uintptr_t)class | 1));
objc_global_mutex_unlock();
return YES;
}
static void
registerSelectors(struct objc_abi_class *rawClass)
{
struct objc_abi_method_list *methodList;
for (methodList = rawClass->methodList; methodList != NULL;
methodList = methodList->next)
for (unsigned int i = 0; i < methodList->count; i++)
objc_register_selector((struct objc_abi_selector *)
&methodList->methods[i]);
}
Class
objc_classname_to_class(const char *name, bool cache)
{
Class class;
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 && fastPath != NULL) {
class = objc_sparsearray_get(fastPath, (uintptr_t)name);
if (class != Nil)
return class;
}
objc_global_mutex_lock();
class = (Class)((uintptr_t)objc_hashtable_get(classes, name) & ~1);
if (cache && fastPath == NULL && --lookupsUntilFastPath == 0)
fastPath = objc_sparsearray_new(sizeof(uintptr_t));
if (cache && fastPath != NULL)
objc_sparsearray_set(fastPath, (uintptr_t)name, class);
objc_global_mutex_unlock();
return class;
}
static void
callMethod(Class class, const char *method)
{
SEL selector = sel_registerName(method);
for (struct objc_method_list *methodList = class->isa->methodList;
methodList != NULL; methodList = methodList->next)
for (unsigned int i = 0; i < methodList->count; i++)
if (sel_isEqual((SEL)&methodList->methods[i].selector,
selector))
((void (*)(id, SEL))methodList->methods[i]
.implementation)(class, selector);
}
static bool
hasLoad(Class class)
{
SEL selector = sel_registerName("load");
for (struct objc_method_list *methodList = class->isa->methodList;
methodList != NULL; methodList = methodList->next)
for (size_t i = 0; i < methodList->count; i++)
if (sel_isEqual((SEL)&methodList->methods[i].selector,
selector))
return true;
return false;
}
static void
callLoad(Class class)
{
if (class->info & OBJC_CLASS_INFO_LOADED)
return;
if (class->superclass != Nil)
callLoad(class->superclass);
callMethod(class, "load");
class->info |= OBJC_CLASS_INFO_LOADED;
}
void
objc_update_dtable(Class class)
{
struct objc_category **categories;
if (!(class->info & OBJC_CLASS_INFO_DTABLE))
return;
if (class->DTable == emptyDTable)
class->DTable = objc_dtable_new();
if (class->superclass != Nil)
objc_dtable_copy(class->DTable, class->superclass->DTable);
for (struct objc_method_list *methodList = class->methodList;
methodList != NULL; methodList = methodList->next)
for (unsigned int i = 0; i < methodList->count; i++)
objc_dtable_set(class->DTable,
(uint32_t)methodList->methods[i].selector.UID,
methodList->methods[i].implementation);
if ((categories = objc_categories_for_class(class)) != NULL) {
for (unsigned int i = 0; categories[i] != NULL; i++) {
struct objc_method_list *methodList =
(class->info & OBJC_CLASS_INFO_CLASS
? categories[i]->instanceMethods
: categories[i]->classMethods);
for (; methodList != NULL;
methodList = methodList->next)
for (unsigned int j = 0;
j < methodList->count; j++)
objc_dtable_set(class->DTable,
(uint32_t)methodList->methods[j]
.selector.UID,
methodList->methods[j]
.implementation);
}
}
if (class->subclassList != NULL)
for (Class *iter = class->subclassList; *iter != NULL; iter++)
objc_update_dtable(*iter);
}
static void
addSubclass(Class class)
{
size_t i;
if (class->superclass->subclassList == NULL) {
if ((class->superclass->subclassList =
malloc(2 * sizeof(Class))) == NULL)
OBJC_ERROR("Not enough memory for subclass list of "
"class %s!", class->superclass->name);
class->superclass->subclassList[0] = class;
class->superclass->subclassList[1] = Nil;
return;
}
for (i = 0; class->superclass->subclassList[i] != Nil; i++);
class->superclass->subclassList =
realloc(class->superclass->subclassList, (i + 2) * sizeof(Class));
if (class->superclass->subclassList == NULL)
OBJC_ERROR("Not enough memory for subclass list of class %s\n",
class->superclass->name);
class->superclass->subclassList[i] = class;
class->superclass->subclassList[i + 1] = Nil;
}
static void
updateIVarOffsets(Class class)
{
if (!(class->info & OBJC_CLASS_INFO_NEW_ABI))
return;
if (class->instanceSize > 0)
return;
class->instanceSize = -class->instanceSize;
if (class->superclass != Nil) {
class->instanceSize += class->superclass->instanceSize;
if (class->iVars != NULL) {
for (unsigned int i = 0; i < class->iVars->count; i++) {
class->iVars->iVars[i].offset +=
class->superclass->instanceSize;
*class->iVarOffsets[i] =
class->iVars->iVars[i].offset;
}
}
} else
for (unsigned int i = 0; i < class->iVars->count; i++)
*class->iVarOffsets[i] = class->iVars->iVars[i].offset;
}
static void
setupClass(Class class)
{
const char *superclassName;
if (class->info & OBJC_CLASS_INFO_SETUP)
return;
superclassName = ((struct objc_abi_class *)class)->superclass;
if (superclassName != NULL) {
Class super = objc_classname_to_class(superclassName, false);
if (super == Nil)
return;
setupClass(super);
if (!(super->info & OBJC_CLASS_INFO_SETUP))
return;
class->superclass = super;
class->isa->superclass = super->isa;
addSubclass(class);
addSubclass(class->isa);
} else
class->isa->superclass = class;
updateIVarOffsets(class);
class->info |= OBJC_CLASS_INFO_SETUP;
class->isa->info |= OBJC_CLASS_INFO_SETUP;
}
static void
initializeClass(Class class)
{
if (class->info & OBJC_CLASS_INFO_INITIALIZED)
return;
if (class->superclass)
initializeClass(class->superclass);
class->info |= OBJC_CLASS_INFO_DTABLE;
class->isa->info |= OBJC_CLASS_INFO_DTABLE;
objc_update_dtable(class);
objc_update_dtable(class->isa);
/*
* Set it first to prevent calling it recursively due to message sends
* in the initialize method
*/
class->info |= OBJC_CLASS_INFO_INITIALIZED;
class->isa->info |= OBJC_CLASS_INFO_INITIALIZED;
if (class_respondsToSelector(object_getClass(class),
@selector(initialize)))
[class initialize];
}
void
objc_initialize_class(Class class)
{
if (class->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 (class->info & OBJC_CLASS_INFO_INITIALIZED) {
objc_global_mutex_unlock();
return;
}
setupClass(class);
if (!(class->info & OBJC_CLASS_INFO_SETUP)) {
objc_global_mutex_unlock();
return;
}
initializeClass(class);
objc_global_mutex_unlock();
}
static void
processLoadQueue()
{
for (size_t i = 0; i < loadQueueCount; i++) {
setupClass(loadQueue[i]);
if (loadQueue[i]->info & OBJC_CLASS_INFO_SETUP) {
callLoad(loadQueue[i]);
loadQueueCount--;
if (loadQueueCount == 0) {
free(loadQueue);
loadQueue = NULL;
continue;
}
loadQueue[i] = loadQueue[loadQueueCount];
loadQueue = realloc(loadQueue,
sizeof(Class) * loadQueueCount);
if (loadQueue == 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->classDefsCount; i++) {
struct objc_abi_class *rawClass =
(struct objc_abi_class *)symtab->defs[i];
registerClass(rawClass);
registerSelectors(rawClass);
registerSelectors(rawClass->metaclass);
}
for (uint16_t i = 0; i < symtab->classDefsCount; i++) {
Class class = (Class)symtab->defs[i];
if (hasLoad(class)) {
setupClass(class);
if (class->info & OBJC_CLASS_INFO_SETUP)
callLoad(class);
else {
loadQueue = realloc(loadQueue,
sizeof(Class) * (loadQueueCount + 1));
if (loadQueue == NULL)
OBJC_ERROR("Not enough memory for load "
"queue!");
loadQueue[loadQueueCount++] = class;
}
} else
class->info |= OBJC_CLASS_INFO_LOADED;
}
processLoadQueue();
}
Class
objc_allocateClassPair(Class superclass, const char *name, size_t extraBytes)
{
struct objc_class *class, *metaclass;
Class iter, rootclass = Nil;
if (extraBytes > LONG_MAX)
OBJC_ERROR("extra_bytes out of range!")
if ((class = calloc(1, sizeof(*class))) == NULL ||
(metaclass = calloc(1, sizeof(*class))) == NULL)
OBJC_ERROR("Not enough memory to allocate class pair for class "
"%s!", name)
class->isa = metaclass;
class->superclass = superclass;
class->name = name;
class->info = OBJC_CLASS_INFO_CLASS;
class->instanceSize = (superclass != Nil ?
superclass->instanceSize : 0) + (long)extraBytes;
for (iter = superclass; iter != Nil; iter = iter->superclass)
rootclass = iter;
metaclass->isa = (rootclass != Nil ? rootclass->isa : class);
metaclass->superclass = (superclass != Nil ? superclass->isa : Nil);
metaclass->name = name;
metaclass->info = OBJC_CLASS_INFO_CLASS;
metaclass->instanceSize = (superclass != Nil ?
superclass->isa->instanceSize : 0) + (long)extraBytes;
return class;
}
void
objc_registerClassPair(Class class)
{
objc_global_mutex_lock();
registerClass((struct objc_abi_class *)class);
if (class->superclass != Nil) {
addSubclass(class);
addSubclass(class->isa);
}
class->info |= OBJC_CLASS_INFO_SETUP;
class->isa->info |= OBJC_CLASS_INFO_SETUP;
if (hasLoad(class))
callLoad(class);
else
class->info |= OBJC_CLASS_INFO_LOADED;
processLoadQueue();
objc_global_mutex_unlock();
}
Class
objc_lookUpClass(const char *name)
{
Class class;
if ((class = objc_classname_to_class(name, true)) == NULL)
return Nil;
if (class->info & OBJC_CLASS_INFO_SETUP)
return class;
objc_global_mutex_lock();
setupClass(class);
objc_global_mutex_unlock();
if (!(class->info & OBJC_CLASS_INFO_SETUP))
return Nil;
return class;
}
Class
objc_getClass(const char *name)
{
return objc_lookUpClass(name);
}
Class
objc_getRequiredClass(const char *name)
{
Class class;
if ((class = objc_getClass(name)) == Nil)
OBJC_ERROR("Class %s not found!", name);
return class;
}
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 *buffer, unsigned int count)
{
unsigned int j;
objc_global_mutex_lock();
if (buffer == NULL)
return classesCount;
if (classesCount < count)
count = classesCount;
j = 0;
for (uint32_t i = 0; i < classes->size; i++) {
void *class;
if (j >= count) {
objc_global_mutex_unlock();
return j;
}
if (classes->data[i] == NULL)
continue;
if (strcmp(classes->data[i]->key, "Protocol") == 0)
continue;
class = (Class)classes->data[i]->object;
if (class == Nil || (uintptr_t)class & 1)
continue;
buffer[j++] = class;
}
objc_global_mutex_unlock();
return j;
}
Class *
objc_copyClassList(unsigned int *length)
{
Class *ret;
unsigned int count;
objc_global_mutex_lock();
if ((ret = malloc((classesCount + 1) * sizeof(Class))) == NULL)
OBJC_ERROR("Failed to allocate memory for class list!");
count = objc_getClassList(ret, classesCount);
OF_ENSURE(count == classesCount);
ret[count] = Nil;
if (length != NULL)
*length = count;
objc_global_mutex_unlock();
return ret;
}
bool
class_isMetaClass(Class class)
{
if (class == Nil)
return false;
return (class->info & OBJC_CLASS_INFO_METACLASS);
}
const char *
class_getName(Class class)
{
if (class == Nil)
return "";
return class->name;
}
Class
class_getSuperclass(Class class)
{
if (class == Nil)
return Nil;
return class->superclass;
}
unsigned long
class_getInstanceSize(Class class)
{
if (class == Nil)
return 0;
return class->instanceSize;
}
IMP
class_getMethodImplementation(Class class, SEL selector)
{
/*
* 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 (class == Nil)
return NULL;
dummy.isa = class;
return objc_msg_lookup((id)&dummy, selector);
}
IMP
class_getMethodImplementation_stret(Class class, SEL selector)
{
/*
* Same as above, but use objc_msg_lookup_stret instead, so that the
* correct forwarding handler is returned.
*/
struct {
Class isa;
} dummy;
if (class == Nil)
return NULL;
dummy.isa = class;
return objc_msg_lookup_stret((id)&dummy, selector);
}
static struct objc_method *
getMethod(Class class, SEL selector)
{
struct objc_category **categories;
if ((categories = objc_categories_for_class(class)) != NULL) {
for (; *categories != NULL; categories++) {
struct objc_method_list *methodList =
(class->info & OBJC_CLASS_INFO_METACLASS
? (*categories)->classMethods
: (*categories)->instanceMethods);
for (; methodList != NULL;
methodList = methodList->next)
for (unsigned int i = 0;
i < methodList->count; i++)
if (sel_isEqual((SEL)
&methodList->methods[i].selector,
selector))
return &methodList->methods[i];
}
}
for (struct objc_method_list *methodList = class->methodList;
methodList != NULL; methodList = methodList->next)
for (unsigned int i = 0; i < methodList->count; i++)
if (sel_isEqual((SEL)&methodList->methods[i].selector,
selector))
return &methodList->methods[i];
return NULL;
}
static void
addMethod(Class class, SEL selector, IMP implementation,
const char *typeEncoding)
{
struct objc_method_list *methodList;
/* FIXME: We need a way to free this at objc_exit() */
if ((methodList = malloc(sizeof(*methodList))) == NULL)
OBJC_ERROR("Not enough memory to replace method!");
methodList->next = class->methodList;
methodList->count = 1;
methodList->methods[0].selector.UID = selector->UID;
methodList->methods[0].selector.typeEncoding = typeEncoding;
methodList->methods[0].implementation = implementation;
class->methodList = methodList;
objc_update_dtable(class);
}
const char *
class_getMethodTypeEncoding(Class class, SEL selector)
{
struct objc_method *method;
if (class == Nil)
return NULL;
objc_global_mutex_lock();
if ((method = getMethod(class, selector)) != NULL) {
const char *ret = method->selector.typeEncoding;
objc_global_mutex_unlock();
return ret;
}
objc_global_mutex_unlock();
if (class->superclass != Nil)
return class_getMethodTypeEncoding(class->superclass, selector);
return NULL;
}
bool
class_addMethod(Class class, SEL selector, IMP implementation,
const char *typeEncoding)
{
bool ret;
objc_global_mutex_lock();
if (getMethod(class, selector) == NULL) {
addMethod(class, selector, implementation, typeEncoding);
ret = true;
} else
ret = false;
objc_global_mutex_unlock();
return ret;
}
IMP
class_replaceMethod(Class class, SEL selector, IMP implementation,
const char *typeEncoding)
{
struct objc_method *method;
IMP oldImplementation;
objc_global_mutex_lock();
if ((method = getMethod(class, selector)) != NULL) {
oldImplementation = method->implementation;
method->implementation = implementation;
objc_update_dtable(class);
} else {
oldImplementation = NULL;
addMethod(class, selector, implementation, typeEncoding);
}
objc_global_mutex_unlock();
return oldImplementation;
}
Class
object_getClass(id object_)
{
struct objc_object *object;
if (object_ == nil)
return Nil;
object = (struct objc_object *)object_;
return object->isa;
}
Class
object_setClass(id object_, Class class)
{
struct objc_object *object;
Class old;
if (object_ == nil)
return Nil;
object = (struct objc_object *)object_;
old = object->isa;
object->isa = class;
return old;
}
const char *
object_getClassName(id object)
{
return class_getName(object_getClass(object));
}
static void
unregisterClass(Class class)
{
struct objc_abi_class *rawClass = (struct objc_abi_class *)class;
if ((class->info & OBJC_CLASS_INFO_SETUP) && class->superclass != Nil &&
class->superclass->subclassList != NULL) {
size_t i = SIZE_MAX, count = 0;
Class *tmp;
for (tmp = class->superclass->subclassList;
*tmp != Nil; tmp++) {
if (*tmp == class)
i = count;
count++;
}
if (count > 0 && i < SIZE_MAX) {
tmp = class->superclass->subclassList;
tmp[i] = tmp[count - 1];
tmp[count - 1] = NULL;
if ((tmp = realloc(class->superclass->subclassList,
count * sizeof(Class))) != NULL)
class->superclass->subclassList = tmp;
}
}
if (class->subclassList != NULL) {
free(class->subclassList);
class->subclassList = NULL;
}
if (class->DTable != NULL && class->DTable != emptyDTable)
objc_dtable_free(class->DTable);
class->DTable = NULL;
if ((class->info & OBJC_CLASS_INFO_SETUP) && class->superclass != Nil)
rawClass->superclass = class->superclass->name;
class->info &= ~OBJC_CLASS_INFO_SETUP;
}
void
objc_unregister_class(Class class)
{
while (class->subclassList != NULL && class->subclassList[0] != Nil)
objc_unregister_class(class->subclassList[0]);
if (class->info & OBJC_CLASS_INFO_LOADED)
callMethod(class, "unload");
objc_hashtable_delete(classes, class->name);
if (strcmp(class_getName(class), "Protocol") != 0)
classesCount--;
unregisterClass(class);
unregisterClass(class->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 *class = (Class)classes->data[i]->object;
if (class == Nil || (uintptr_t)class & 1)
continue;
objc_unregister_class(class);
/*
* 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;
}
}
OF_ENSURE(classesCount == 0);
if (emptyDTable != NULL) {
objc_dtable_free(emptyDTable);
emptyDTable = NULL;
}
objc_sparsearray_free(fastPath);
fastPath = NULL;
objc_hashtable_free(classes);
classes = NULL;
}