/* * Copyright (c) 2008-2024 Jonathan Schleifer * * 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 #include #include #include #import "ObjFWRT.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(Class class) { if (classes == NULL) classes = objc_hashtable_new( objc_string_hash, objc_string_equal, 2); objc_hashtable_set(classes, class->name, class); if (emptyDTable == NULL) emptyDTable = objc_dtable_new(); class->dTable = emptyDTable; class->isa->dTable = emptyDTable; if (strcmp(class->name, "Protocol") != 0) classesCount++; } bool class_registerAlias_np(Class class, const char *name) { objc_globalMutex_lock(); if (classes == NULL) { objc_globalMutex_unlock(); return false; } objc_hashtable_set(classes, name, (Class)((uintptr_t)class | 1)); objc_globalMutex_unlock(); return true; } static void registerSelectors(Class class) { struct objc_method_list *iter; unsigned int i; for (iter = class->methodList; iter != NULL; iter = iter->next) for (i = 0; i < iter->count; i++) objc_registerSelector(&iter->methods[i].selector); } Class objc_classnameToClass(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_classnameToClass() 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_classnameToClass() 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_classnameToClass(). The reason for this is that * if the runtime calls into objc_classnameToClass(), 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_globalMutex_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_globalMutex_unlock(); return class; } static void callSelector(Class class, SEL selector) { 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) { static SEL loadSel = NULL; if (loadSel == NULL) loadSel = 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, loadSel)) return true; return false; } static void callLoad(Class class) { static SEL loadSel = NULL; if (loadSel == NULL) loadSel = sel_registerName("load"); if (class->info & OBJC_CLASS_INFO_LOADED) return; if (class->superclass != Nil) callLoad(class->superclass); callSelector(class, loadSel); class->info |= OBJC_CLASS_INFO_LOADED; } void objc_updateDTable(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_categoriesForClass(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_updateDTable(*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 = (const char *)class->superclass; if (superclassName != NULL) { Class super = objc_classnameToClass(superclassName, false); Class rootClass; if (super == Nil) return; setUpClass(super); if (!(super->info & OBJC_CLASS_INFO_SETUP)) return; /* * GCC sets class->isa->isa to the name of the root class, * while Clang just sets it to Nil. Therefore always calculate * it. */ for (Class iter = super; iter != NULL; iter = iter->superclass) rootClass = iter; class->superclass = super; class->isa->isa = rootClass->isa; class->isa->superclass = super->isa; addSubclass(class); addSubclass(class->isa); } else { class->isa->isa = class->isa; class->isa->superclass = class; } updateIvarOffsets(class); class->info |= OBJC_CLASS_INFO_SETUP; class->isa->info |= OBJC_CLASS_INFO_SETUP; } static void initializeClass(Class class) { static SEL initializeSel = NULL; if (initializeSel == NULL) initializeSel = sel_registerName("initialize"); if (class->info & OBJC_CLASS_INFO_INITIALIZED) return; if (class->superclass) initializeClass(class->superclass); /* * Avoid double-initialization: One of the superclasses' +[initialize] * might have called this class and hence it already got initialized. */ if (class->info & OBJC_CLASS_INFO_INITIALIZED) return; class->info |= OBJC_CLASS_INFO_DTABLE; class->isa->info |= OBJC_CLASS_INFO_DTABLE; objc_updateDTable(class); objc_updateDTable(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; /* * +[initialize] might get called from some +[load], before the * constructors of this compilation module have been called, at which * point the selector would not be properly initialized. */ if (class_respondsToSelector(object_getClass(class), initializeSel)) { void (*initialize)(id, SEL) = (void (*)(id, SEL)) objc_msg_lookup(class, initializeSel); initialize(class, initializeSel); } } void objc_initializeClass(Class class) { if (class->info & OBJC_CLASS_INFO_INITIALIZED) return; objc_globalMutex_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_globalMutex_unlock(); return; } setUpClass(class); if (!(class->info & OBJC_CLASS_INFO_SETUP)) { objc_globalMutex_unlock(); return; } initializeClass(class); objc_globalMutex_unlock(); } static void processLoadQueue(void) { 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_registerAllClasses(struct objc_symtab *symtab) { for (uint16_t i = 0; i < symtab->classDefsCount; i++) { Class class = (Class)symtab->defs[i]; registerClass(class); registerSelectors(class); registerSelectors(class->isa); } 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 ((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); if (extraBytes > LONG_MAX || LONG_MAX - class->instanceSize < (long)extraBytes) OBJC_ERROR("extraBytes too large!"); class->instanceSize += (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_globalMutex_lock(); registerClass(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_globalMutex_unlock(); } Class objc_lookUpClass(const char *name) { Class class; if ((class = objc_classnameToClass(name, true)) == NULL) return Nil; if (class->info & OBJC_CLASS_INFO_SETUP) return class; objc_globalMutex_lock(); setUpClass(class); objc_globalMutex_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_globalMutex_lock(); if (buffer == NULL) { count = classesCount; objc_globalMutex_unlock(); return count; } if (classesCount < count) count = classesCount; j = 0; for (uint32_t i = 0; i < classes->size; i++) { void *class; if (j >= count) { objc_globalMutex_unlock(); return j; } if (classes->data[i] == NULL || classes->data[i] == &objc_deletedBucket) 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_globalMutex_unlock(); return j; } Class * objc_copyClassList(unsigned int *length) { Class *ret; unsigned int count; objc_globalMutex_lock(); if ((ret = malloc((classesCount + 1) * sizeof(Class))) == NULL) OBJC_ERROR("Failed to allocate memory for class list!"); count = objc_getClassList(ret, classesCount); if (count != classesCount) OBJC_ERROR("Fatal internal inconsistency!"); ret[count] = Nil; if (length != NULL) *length = count; objc_globalMutex_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_categoriesForClass(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_deinit() */ 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_updateDTable(class); } Method #if defined(__clang__) && __has_attribute(__optnone__) && \ __clang_major__ == 3 && __clang_minor__ <= 7 /* Work around an ICE in Clang 3.7.0 on Windows/x86 */ __attribute__((__optnone__)) #endif class_getInstanceMethod(Class class, SEL selector) { Method method; Class superclass; if (class == Nil) return NULL; objc_globalMutex_lock(); if ((method = getMethod(class, selector)) != NULL) { objc_globalMutex_unlock(); return method; } superclass = class->superclass; objc_globalMutex_unlock(); if (superclass != Nil) return class_getInstanceMethod(superclass, selector); return NULL; } bool class_addMethod(Class class, SEL selector, IMP implementation, const char *typeEncoding) { bool ret; objc_globalMutex_lock(); if (getMethod(class, selector) == NULL) { addMethod(class, selector, implementation, typeEncoding); ret = true; } else ret = false; objc_globalMutex_unlock(); return ret; } IMP class_replaceMethod(Class class, SEL selector, IMP implementation, const char *typeEncoding) { struct objc_method *method; IMP oldImplementation; objc_globalMutex_lock(); if ((method = getMethod(class, selector)) != NULL) { oldImplementation = method->implementation; method->implementation = implementation; objc_updateDTable(class); } else { oldImplementation = NULL; addMethod(class, selector, implementation, typeEncoding); } objc_globalMutex_unlock(); return oldImplementation; } Class object_getClass(id object_) { struct objc_object *object; if (object_ == nil) return Nil; if (object_isTaggedPointer(object_)) return object_getTaggedPointerClass(object_); 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) { 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) class->superclass = (Class)class->superclass->name; class->info &= ~OBJC_CLASS_INFO_SETUP; } void objc_unregisterClass(Class class) { static SEL unloadSel = NULL; objc_globalMutex_lock(); if (unloadSel == NULL) unloadSel = sel_registerName("unload"); while (class->subclassList != NULL && class->subclassList[0] != Nil) objc_unregisterClass(class->subclassList[0]); if (class->info & OBJC_CLASS_INFO_LOADED) callSelector(class, unloadSel); objc_hashtable_delete(classes, class->name); if (strcmp(class_getName(class), "Protocol") != 0) classesCount--; unregisterClass(class); unregisterClass(class->isa); objc_globalMutex_unlock(); } void objc_unregisterAllClasses(void) { if (classes == NULL) return; for (uint32_t i = 0; i < classes->size; i++) { if (classes->data[i] != NULL && classes->data[i] != &objc_deletedBucket) { void *class = (Class)classes->data[i]->object; if (class == Nil || (uintptr_t)class & 1) continue; objc_unregisterClass(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; } } if (classesCount != 0) OBJC_ERROR("Fatal internal inconsistency!"); if (emptyDTable != NULL) { objc_dtable_free(emptyDTable); emptyDTable = NULL; } objc_sparsearray_free(fastPath); fastPath = NULL; objc_hashtable_free(classes); classes = NULL; }