/*
* Copyright (c) 1999-2007 Apple Inc. All Rights Reserved.
*
* @APPLE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this
* file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_LICENSE_HEADER_END@
*/
/***********************************************************************
* objc-class.m
* Copyright 1988-1997, Apple Computer, Inc.
* Author: s. naroff
**********************************************************************/
/***********************************************************************
* Lazy method list arrays and method list locking (2004-10-19)
*
* cls->methodLists may be in one of three forms:
* 1. NULL: The class has no methods.
* 2. non-NULL, with CLS_NO_METHOD_ARRAY set: cls->methodLists points
* to a single method list, which is the class's only method list.
* 3. non-NULL, with CLS_NO_METHOD_ARRAY clear: cls->methodLists points to
* an array of method list pointers. The end of the array's block
* is set to -1. If the actual number of method lists is smaller
* than that, the rest of the array is NULL.
*
* Attaching categories and adding and removing classes may change
* the form of the class list. In addition, individual method lists
* may be reallocated when fixed up.
*
* Classes are initially read as #1 or #2. If a category is attached
* or other methods added, the class is changed to #3. Once in form #3,
* the class is never downgraded to #1 or #2, even if methods are removed.
* Classes added with objc_addClass are initially either #1 or #3.
*
* Accessing and manipulating a class's method lists are synchronized,
* to prevent races when one thread restructures the list. However,
* if the class is not yet in use (i.e. not in class_hash), then the
* thread loading the class may access its method lists without locking.
*
* The following functions acquire methodListLock:
* class_getInstanceMethod
* class_getClassMethod
* class_nextMethodList
* class_addMethods
* class_removeMethods
* class_respondsToMethod
* _class_lookupMethodAndLoadCache
* lookupMethodInClassAndLoadCache
* _objc_add_category_flush_caches
*
* The following functions don't acquire methodListLock because they
* only access method lists during class load and unload:
* _objc_register_category
* _resolve_categories_for_class (calls _objc_add_category)
* add_class_to_loadable_list
* _objc_addClass
* _objc_remove_classes_in_image
*
* The following functions use method lists without holding methodListLock.
* The caller must either hold methodListLock, or be loading the class.
* _getMethod (called by class_getInstanceMethod, class_getClassMethod,
* and class_respondsToMethod)
* _findMethodInClass (called by _class_lookupMethodAndLoadCache,
* lookupMethodInClassAndLoadCache, _getMethod)
* _findMethodInList (called by _findMethodInClass)
* nextMethodList (called by _findMethodInClass and class_nextMethodList
* fixupSelectorsInMethodList (called by nextMethodList)
* _objc_add_category (called by _objc_add_category_flush_caches,
* resolve_categories_for_class and _objc_register_category)
* _objc_insertMethods (called by class_addMethods and _objc_add_category)
* _objc_removeMethods (called by class_removeMethods)
* _objcTweakMethodListPointerForClass (called by _objc_insertMethods)
* get_base_method_list (called by add_class_to_loadable_list)
* lookupNamedMethodInMethodList (called by add_class_to_loadable_list)
***********************************************************************/
/***********************************************************************
* Thread-safety of class info bits (2004-10-19)
*
* Some class info bits are used to store mutable runtime state.
* Modifications of the info bits at particular times need to be
* synchronized to prevent races.
*
* Three thread-safe modification functions are provided:
* _class_setInfo() // atomically sets some bits
* _class_clearInfo() // atomically clears some bits
* _class_changeInfo() // atomically sets some bits and clears others
* These replace CLS_SETINFO() for the multithreaded cases.
*
* Three modification windows are defined:
* - compile time
* - class construction or image load (before +load) in one thread
* - multi-threaded messaging and method caches
*
* Info bit modification at compile time and class construction do not
* need to be locked, because only one thread is manipulating the class.
* Info bit modification during messaging needs to be locked, because
* there may be other threads simultaneously messaging or otherwise
* manipulating the class.
*
* Modification windows for each flag:
*
* CLS_CLASS: compile-time and class load
* CLS_META: compile-time and class load
* CLS_INITIALIZED: +initialize
* CLS_POSING: messaging
* CLS_MAPPED: compile-time
* CLS_FLUSH_CACHE: class load and messaging
* CLS_GROW_CACHE: messaging
* CLS_NEED_BIND: unused
* CLS_METHOD_ARRAY: unused
* CLS_JAVA_HYBRID: JavaBridge only
* CLS_JAVA_CLASS: JavaBridge only
* CLS_INITIALIZING: messaging
* CLS_FROM_BUNDLE: class load
* CLS_HAS_CXX_STRUCTORS: compile-time and class load
* CLS_NO_METHOD_ARRAY: class load and messaging
* CLS_HAS_LOAD_METHOD: class load
*
* CLS_INITIALIZED and CLS_INITIALIZING have additional thread-safety
* constraints to support thread-safe +initialize. See "Thread safety
* during class initialization" for details.
*
* CLS_JAVA_HYBRID and CLS_JAVA_CLASS are set immediately after JavaBridge
* calls objc_addClass(). The JavaBridge does not use an atomic update,
* but the modification counts as "class construction" unless some other
* thread quickly finds the class via the class list. This race is
* small and unlikely in well-behaved code.
*
* Most info bits that may be modified during messaging are also never
* read without a lock. There is no general read lock for the info bits.
* CLS_INITIALIZED: classInitLock
* CLS_FLUSH_CACHE: cacheUpdateLock
* CLS_GROW_CACHE: cacheUpdateLock
* CLS_NO_METHOD_ARRAY: methodListLock
* CLS_INITIALIZING: classInitLock
***********************************************************************/
/***********************************************************************
* Imports.
**********************************************************************/
#include "objc-private.h"
#include "objc-abi.h"
#include "objc-auto.h"
#include <objc/message.h>
/* overriding the default object allocation and error handling routines */
OBJC_EXPORT id (*_alloc)(Class, size_t);
OBJC_EXPORT id (*_copy)(id, size_t);
OBJC_EXPORT id (*_realloc)(id, size_t);
OBJC_EXPORT id (*_dealloc)(id);
OBJC_EXPORT id (*_zoneAlloc)(Class, size_t, void *);
OBJC_EXPORT id (*_zoneRealloc)(id, size_t, void *);
OBJC_EXPORT id (*_zoneCopy)(id, size_t, void *);
/***********************************************************************
* Function prototypes internal to this module.
**********************************************************************/
static IMP lookupMethodInClassAndLoadCache(Class cls, SEL sel);
static Method look_up_method(Class cls, SEL sel, BOOL withCache, BOOL withResolver);
/***********************************************************************
* Static data internal to this module.
**********************************************************************/
#if !TARGET_OS_WIN32 && !defined(__arm__)
# define MESSAGE_LOGGING
#endif
#if defined(MESSAGE_LOGGING)
// Method call logging
static int LogObjCMessageSend (BOOL isClassMethod, const char * objectsClass, const char * implementingClass, SEL selector);
typedef int (*ObjCLogProc)(BOOL, const char *, const char *, SEL);
static int objcMsgLogFD = (-1);
static ObjCLogProc objcMsgLogProc = &LogObjCMessageSend;
static int objcMsgLogEnabled = 0;
#endif
/***********************************************************************
* Information about multi-thread support:
*
* Since we do not lock many operations which walk the superclass, method
* and ivar chains, these chains must remain intact once a class is published
* by inserting it into the class hashtable. All modifications must be
* atomic so that someone walking these chains will always geta valid
* result.
***********************************************************************/
/***********************************************************************
* object_getClass.
* Locking: None. If you add locking, tell gdb (rdar://7516456).
**********************************************************************/
Class object_getClass(id obj)
{
return _object_getClass(obj);
}
/***********************************************************************
* object_setClass.
**********************************************************************/
Class object_setClass(id obj, Class cls)
{
if (obj) {
Class old;
do {
old = obj->isa;
} while (! OSAtomicCompareAndSwapPtrBarrier(old, cls, (void * volatile *)&obj->isa));
if (old && _class_instancesHaveAssociatedObjects(old)) {
_class_setInstancesHaveAssociatedObjects(cls);
}
return old;
}
else return Nil;
}
/***********************************************************************
* object_getClassName.
**********************************************************************/
const char *object_getClassName(id obj)
{
Class isa = _object_getClass(obj);
if (isa) return _class_getName(isa);
else return "nil";
}
/***********************************************************************
* object_getIndexedIvars.
**********************************************************************/
void *object_getIndexedIvars(id obj)
{
// ivars are tacked onto the end of the object
if (obj) return ((char *) obj) + _class_getInstanceSize(_object_getClass(obj));
else return NULL;
}
Ivar object_setInstanceVariable(id obj, const char *name, void *value)
{
Ivar ivar = NULL;
if (obj && name) {
if ((ivar = class_getInstanceVariable(_object_getClass(obj), name))) {
object_setIvar(obj, ivar, (id)value);
}
}
return ivar;
}
Ivar object_getInstanceVariable(id obj, const char *name, void **value)
{
if (obj && name) {
Ivar ivar;
if ((ivar = class_getInstanceVariable(_object_getClass(obj), name))) {
if (value) *value = (void *)object_getIvar(obj, ivar);
return ivar;
}
}
if (value) *value = NULL;
return NULL;
}
static BOOL is_scanned_offset(ptrdiff_t ivar_offset, const uint8_t *layout) {
ptrdiff_t index = 0, ivar_index = ivar_offset / sizeof(void*);
uint8_t byte;
while ((byte = *layout++)) {
unsigned skips = (byte >> 4);
unsigned scans = (byte & 0x0F);
index += skips;
while (scans--) {
if (index == ivar_index) return YES;
if (index > ivar_index) return NO;
++index;
}
}
return NO;
}
// FIXME: this could be optimized.
static Class _ivar_getClass(Class cls, Ivar ivar) {
Class ivar_class = NULL;
const char *ivar_name = ivar_getName(ivar);
Ivar named_ivar = _class_getVariable(cls, ivar_name, &ivar_class);
if (named_ivar) {
// the same ivar name can appear multiple times along the superclass chain.
while (named_ivar != ivar && ivar_class != NULL) {
ivar_class = class_getSuperclass(ivar_class);
named_ivar = _class_getVariable(cls, ivar_getName(ivar), &ivar_class);
}
}
return ivar_class;
}
void object_setIvar(id obj, Ivar ivar, id value)
{
if (obj && ivar) {
Class cls = _ivar_getClass(object_getClass(obj), ivar);
ptrdiff_t ivar_offset = ivar_getOffset(ivar);
id *location = (id *)((char *)obj + ivar_offset);
// if this ivar is a member of an ARR compiled class, then issue the correct barrier according to the layout.
if (_class_usesAutomaticRetainRelease(cls)) {
// for ARR, layout strings are relative to the instance start.
uint32_t instanceStart = _class_getInstanceStart(cls);
const uint8_t *weak_layout = class_getWeakIvarLayout(cls);
if (weak_layout && is_scanned_offset(ivar_offset - instanceStart, weak_layout)) {
// use the weak system to write to this variable.
objc_storeWeak(location, value);
return;
}
const uint8_t *strong_layout = class_getIvarLayout(cls);
if (strong_layout && is_scanned_offset(ivar_offset - instanceStart, strong_layout)) {
objc_storeStrong(location, value);
return;
}
}
#if SUPPORT_GC
if (UseGC) {
// for GC, check for weak references.
const uint8_t *weak_layout = class_getWeakIvarLayout(cls);
if (weak_layout && is_scanned_offset(ivar_offset, weak_layout)) {
objc_assign_weak(value, location);
}
}
objc_assign_ivar_internal(value, obj, ivar_offset);
#else
*location = value;
#endif
}
}
id object_getIvar(id obj, Ivar ivar)
{
if (obj && ivar) {
Class cls = _object_getClass(obj);
ptrdiff_t ivar_offset = ivar_getOffset(ivar);
if (_class_usesAutomaticRetainRelease(cls)) {
// for ARR, layout strings are relative to the instance start.
uint32_t instanceStart = _class_getInstanceStart(cls);
const uint8_t *weak_layout = class_getWeakIvarLayout(cls);
if (weak_layout && is_scanned_offset(ivar_offset - instanceStart, weak_layout)) {
// use the weak system to read this variable.
id *location = (id *)((char *)obj + ivar_offset);
return objc_loadWeak(location);
}
}
id *idx = (id *)((char *)obj + ivar_offset);
#if SUPPORT_GC
if (UseGC) {
const uint8_t *weak_layout = class_getWeakIvarLayout(cls);
if (weak_layout && is_scanned_offset(ivar_offset, weak_layout)) {
return objc_read_weak(idx);
}
}
#endif
return *idx;
}
return NULL;
}
/***********************************************************************
* object_cxxDestructFromClass.
* Call C++ destructors on obj, starting with cls's
* dtor method (if any) followed by superclasses' dtors (if any),
* stopping at cls's dtor (if any).
* Uses methodListLock and cacheUpdateLock. The caller must hold neither.
**********************************************************************/
static void object_cxxDestructFromClass(id obj, Class cls)
{
void (*dtor)(id);
// Call cls's dtor first, then superclasses's dtors.
for ( ; cls != NULL; cls = _class_getSuperclass(cls)) {
if (!_class_hasCxxStructors(cls)) return;
dtor = (void(*)(id))
lookupMethodInClassAndLoadCache(cls, SEL_cxx_destruct);
if (dtor != (void(*)(id))_objc_msgForward_internal) {
if (PrintCxxCtors) {
_objc_inform("CXX: calling C++ destructors for class %s",
_class_getName(cls));
}
(*dtor)(obj);
}
}
}
/***********************************************************************
* object_cxxDestruct.
* Call C++ destructors on obj, if any.
* Uses methodListLock and cacheUpdateLock. The caller must hold neither.
**********************************************************************/
void object_cxxDestruct(id obj)
{
if (!obj) return;
if (OBJC_IS_TAGGED_PTR(obj)) return;
object_cxxDestructFromClass(obj, obj->isa); // need not be object_getClass
}
/***********************************************************************
* object_cxxConstructFromClass.
* Recursively call C++ constructors on obj, starting with base class's
* ctor method (if any) followed by subclasses' ctors (if any), stopping
* at cls's ctor (if any).
* Returns YES if construction succeeded.
* Returns NO if some constructor threw an exception. The exception is
* caught and discarded. Any partial construction is destructed.
* Uses methodListLock and cacheUpdateLock. The caller must hold neither.
*
* .cxx_construct returns id. This really means:
* return self: construction succeeded
* return nil: construction failed because a C++ constructor threw an exception
**********************************************************************/
static BOOL object_cxxConstructFromClass(id obj, Class cls)
{
id (*ctor)(id);
Class supercls;
// Stop if neither this class nor any superclass has ctors.
if (!_class_hasCxxStructors(cls)) return YES; // no ctor - ok
supercls = _class_getSuperclass(cls);
// Call superclasses' ctors first, if any.
if (supercls) {
BOOL ok = object_cxxConstructFromClass(obj, supercls);
if (!ok) return NO; // some superclass's ctor failed - give up
}
// Find this class's ctor, if any.
ctor = (id(*)(id))lookupMethodInClassAndLoadCache(cls, SEL_cxx_construct);
if (ctor == (id(*)(id))_objc_msgForward_internal) return YES; // no ctor - ok
// Call this class's ctor.
if (PrintCxxCtors) {
_objc_inform("CXX: calling C++ constructors for class %s", _class_getName(cls));
}
if ((*ctor)(obj)) return YES; // ctor called and succeeded - ok
// This class's ctor was called and failed.
// Call superclasses's dtors to clean up.
if (supercls) object_cxxDestructFromClass(obj, supercls);
return NO;
}
/***********************************************************************
* object_cxxConstructFromClass.
* Call C++ constructors on obj, if any.
* Returns YES if construction succeeded.
* Returns NO if some constructor threw an exception. The exception is
* caught and discarded. Any partial construction is destructed.
* Uses methodListLock and cacheUpdateLock. The caller must hold neither.
**********************************************************************/
BOOL object_cxxConstruct(id obj)
{
if (!obj) return YES;
if (OBJC_IS_TAGGED_PTR(obj)) return YES;
return object_cxxConstructFromClass(obj, obj->isa); // need not be object_getClass
}
/***********************************************************************
* _class_resolveClassMethod
* Call +resolveClassMethod and return the method added or NULL.
* cls should be a metaclass.
* Assumes the method doesn't exist already.
**********************************************************************/
static Method _class_resolveClassMethod(Class cls, SEL sel)
{
BOOL resolved;
Method meth = NULL;
Class clsInstance;
if (!look_up_method(cls, SEL_resolveClassMethod,
YES /*cache*/, NO /*resolver*/))
{
return NULL;
}
// GrP fixme same hack as +initialize
if (strncmp(_class_getName(cls), "_%", 2) == 0) {
// Posee's meta's name is smashed and isn't in the class_hash,
// so objc_getClass doesn't work.
const char *baseName = strchr(_class_getName(cls), '%'); // get posee's real name
clsInstance = (Class)objc_getClass(baseName);
} else {
clsInstance = (Class)objc_getClass(_class_getName(cls));
}
resolved = ((BOOL(*)(id, SEL, SEL))objc_msgSend)((id)clsInstance, SEL_resolveClassMethod, sel);
if (resolved) {
// +resolveClassMethod adds to self->isa
meth = look_up_method(cls, sel, YES/*cache*/, NO/*resolver*/);
if (!meth) {
// Method resolver didn't add anything?
_objc_inform("+[%s resolveClassMethod:%s] returned YES, but "
"no new implementation of +[%s %s] was found",
class_getName(cls),
sel_getName(sel),
class_getName(cls),
sel_getName(sel));
return NULL;
}
}
return meth;
}
/***********************************************************************
* _class_resolveInstanceMethod
* Call +resolveInstanceMethod and return the method added or NULL.
* cls should be a non-meta class.
* Assumes the method doesn't exist already.
**********************************************************************/
static Method _class_resolveInstanceMethod(Class cls, SEL sel)
{
BOOL resolved;
Method meth = NULL;
if (!look_up_method(((id)cls)->isa, SEL_resolveInstanceMethod,
YES /*cache*/, NO /*resolver*/))
{
return NULL;
}
resolved = ((BOOL(*)(id, SEL, SEL))objc_msgSend)((id)cls, SEL_resolveInstanceMethod, sel);
if (resolved) {
// +resolveClassMethod adds to self
meth = look_up_method(cls, sel, YES/*cache*/, NO/*resolver*/);
if (!meth) {
// Method resolver didn't add anything?
_objc_inform("+[%s resolveInstanceMethod:%s] returned YES, but "
"no new implementation of %c[%s %s] was found",
class_getName(cls),
sel_getName(sel),
class_isMetaClass(cls) ? '+' : '-',
class_getName(cls),
sel_getName(sel));
return NULL;
}
}
return meth;
}
/***********************************************************************
* _class_resolveMethod
* Call +resolveClassMethod or +resolveInstanceMethod and return
* the method added or NULL.
* Assumes the method doesn't exist already.
**********************************************************************/
Method _class_resolveMethod(Class cls, SEL sel)
{
Method meth = NULL;
if (_class_isMetaClass(cls)) {
meth = _class_resolveClassMethod(cls, sel);
}
if (!meth) {
meth = _class_resolveInstanceMethod(cls, sel);
}
if (PrintResolving && meth) {
_objc_inform("RESOLVE: method %c[%s %s] dynamically resolved to %p",
class_isMetaClass(cls) ? '+' : '-',
class_getName(cls), sel_getName(sel),
method_getImplementation(meth));
}
return meth;
}
/***********************************************************************
* look_up_method
* Look up a method in the given class and its superclasses.
* If withCache==YES, look in the class's method cache too.
* If withResolver==YES, call +resolveClass/InstanceMethod too.
* Returns NULL if the method is not found.
* +forward:: entries are not returned.
**********************************************************************/
static Method look_up_method(Class cls, SEL sel,
BOOL withCache, BOOL withResolver)
{
Method meth = NULL;
if (withCache) {
meth = _cache_getMethod(cls, sel, _objc_msgForward_internal);
if (meth == (Method)1) {
// Cache contains forward:: . Stop searching.
return NULL;
}
}
if (!meth) meth = _class_getMethod(cls, sel);
if (!meth && withResolver) meth = _class_resolveMethod(cls, sel);
return meth;
}
/***********************************************************************
* class_getInstanceMethod. Return the instance method for the
* specified class and selector.
**********************************************************************/
Method class_getInstanceMethod(Class cls, SEL sel)
{
if (!cls || !sel) return NULL;
return look_up_method(cls, sel, YES/*cache*/, YES/*resolver*/);
}
/***********************************************************************
* class_getClassMethod. Return the class method for the specified
* class and selector.
**********************************************************************/
Method class_getClassMethod(Class cls, SEL sel)
{
if (!cls || !sel) return NULL;
return class_getInstanceMethod(_class_getMeta(cls), sel);
}
/***********************************************************************
* class_getInstanceVariable. Return the named instance variable.
**********************************************************************/
Ivar class_getInstanceVariable(Class cls, const char *name)
{
if (!cls || !name) return NULL;
return _class_getVariable(cls, name, NULL);
}
/***********************************************************************
* class_getClassVariable. Return the named class variable.
**********************************************************************/
Ivar class_getClassVariable(Class cls, const char *name)
{
if (!cls) return NULL;
return class_getInstanceVariable(((id)cls)->isa, name);
}
/***********************************************************************
* gdb_objc_class_changed
* Tell gdb that a class changed. Currently used for OBJC2 ivar layouts only
* Does nothing; gdb sets a breakpoint on it.
**********************************************************************/
BREAKPOINT_FUNCTION(
void gdb_objc_class_changed(Class cls, unsigned long changes, const char *classname)
);
/***********************************************************************
* _objc_flush_caches. Flush the caches of the specified class and any
* of its subclasses. If cls is a meta-class, only meta-class (i.e.
* class method) caches are flushed. If cls is an instance-class, both
* instance-class and meta-class caches are flushed.
**********************************************************************/
void _objc_flush_caches(Class cls)
{
flush_caches (cls, YES);
if (!cls) {
// collectALot if cls==nil
mutex_lock(&cacheUpdateLock);
_cache_collect(true);
mutex_unlock(&cacheUpdateLock);
}
}
/***********************************************************************
* class_respondsToSelector.
**********************************************************************/
BOOL class_respondsToMethod(Class cls, SEL sel)
{
OBJC_WARN_DEPRECATED;
return class_respondsToSelector(cls, sel);
}
BOOL class_respondsToSelector(Class cls, SEL sel)
{
IMP imp;
if (!sel || !cls) return NO;
// Avoids +initialize because it historically did so.
// We're not returning a callable IMP anyway.
imp = lookUpMethod(cls, sel, NO/*initialize*/, YES/*cache*/, nil);
return (imp != (IMP)_objc_msgForward_internal) ? YES : NO;
}
/***********************************************************************
* class_getMethodImplementation.
* Returns the IMP that would be invoked if [obj sel] were sent,
* where obj is an instance of class cls.
**********************************************************************/
IMP class_lookupMethod(Class cls, SEL sel)
{
OBJC_WARN_DEPRECATED;
// No one responds to zero!
if (!sel) {
__objc_error((id)cls, "invalid selector (null)");
}
return class_getMethodImplementation(cls, sel);
}
IMP class_getMethodImplementation(Class cls, SEL sel)
{
IMP imp;
if (!cls || !sel) return NULL;
imp = lookUpMethod(cls, sel, YES/*initialize*/, YES/*cache*/, nil);
// Translate forwarding function to C-callable external version
if (imp == _objc_msgForward_internal) {
return _objc_msgForward;
}
return imp;
}
IMP class_getMethodImplementation_stret(Class cls, SEL sel)
{
IMP imp = class_getMethodImplementation(cls, sel);
// Translate forwarding function to struct-returning version
if (imp == (IMP)&_objc_msgForward /* not _internal! */) {
return (IMP)&_objc_msgForward_stret;
}
return imp;
}
/***********************************************************************
* instrumentObjcMessageSends/logObjcMessageSends.
**********************************************************************/
#if !defined(MESSAGE_LOGGING) && defined(__arm__)
void instrumentObjcMessageSends (BOOL flag)
{
}
#elif defined(MESSAGE_LOGGING)
static int LogObjCMessageSend (BOOL isClassMethod,
const char * objectsClass,
const char * implementingClass,
SEL selector)
{
char buf[ 1024 ];
// Create/open the log file
if (objcMsgLogFD == (-1))
{
snprintf (buf, sizeof(buf), "/tmp/msgSends-%d", (int) getpid ());
objcMsgLogFD = secure_open (buf, O_WRONLY | O_CREAT, geteuid());
if (objcMsgLogFD < 0) {
// no log file - disable logging
objcMsgLogEnabled = 0;
objcMsgLogFD = -1;
return 1;
}
}
// Make the log entry
snprintf(buf, sizeof(buf), "%c %s %s %s\n",
isClassMethod ? '+' : '-',
objectsClass,
implementingClass,
sel_getName(selector));
static OSSpinLock lock = OS_SPINLOCK_INIT;
OSSpinLockLock(&lock);
write (objcMsgLogFD, buf, strlen(buf));
OSSpinLockUnlock(&lock);
// Tell caller to not cache the method
return 0;
}
void instrumentObjcMessageSends (BOOL flag)
{
int enabledValue = (flag) ? 1 : 0;
// Shortcut NOP
if (objcMsgLogEnabled == enabledValue)
return;
// If enabling, flush all method caches so we get some traces
if (flag)
flush_caches (Nil, YES);
// Sync our log file
if (objcMsgLogFD != (-1))
fsync (objcMsgLogFD);
objcMsgLogEnabled = enabledValue;
}
void logObjcMessageSends (ObjCLogProc logProc)
{
if (logProc)
{
objcMsgLogProc = logProc;
objcMsgLogEnabled = 1;
}
else
{
objcMsgLogProc = logProc;
objcMsgLogEnabled = 0;
}
if (objcMsgLogFD != (-1))
fsync (objcMsgLogFD);
}
#endif
/***********************************************************************
* log_and_fill_cache
* Log this method call. If the logger permits it, fill the method cache.
* cls is the method whose cache should be filled.
* implementer is the class that owns the implementation in question.
**********************************************************************/
void
log_and_fill_cache(Class cls, Class implementer, Method meth, SEL sel)
{
#if defined(MESSAGE_LOGGING)
BOOL cacheIt = YES;
if (objcMsgLogEnabled) {
cacheIt = objcMsgLogProc (_class_isMetaClass(implementer) ? YES : NO,
_class_getName(cls),
_class_getName(implementer),
sel);
}
if (cacheIt)
#endif
_cache_fill (cls, meth, sel);
}
/***********************************************************************
* _class_lookupMethodAndLoadCache.
* Method lookup for dispatchers ONLY. OTHER CODE SHOULD USE lookUpMethod().
* This lookup avoids optimistic cache scan because the dispatcher
* already tried that.
**********************************************************************/
IMP _class_lookupMethodAndLoadCache3(id obj, SEL sel, Class cls)
{
return lookUpMethod(cls, sel, YES/*initialize*/, NO/*cache*/, obj);
}
/***********************************************************************
* lookUpMethod.
* The standard method lookup.
* initialize==NO tries to avoid +initialize (but sometimes fails)
* cache==NO skips optimistic unlocked lookup (but uses cache elsewhere)
* Most callers should use initialize==YES and cache==YES.
* inst is an instance of cls or a subclass thereof, or nil if none is known.
* If cls is an un-initialized metaclass then a non-nil inst is faster.
* May return _objc_msgForward_internal. IMPs destined for external use
* must be converted to _objc_msgForward or _objc_msgForward_stret.
**********************************************************************/
IMP lookUpMethod(Class cls, SEL sel, BOOL initialize, BOOL cache, id inst)
{
Class curClass;
IMP methodPC = NULL;
Method meth;
BOOL triedResolver = NO;
// Optimistic cache lookup
if (cache) {
methodPC = _cache_getImp(cls, sel);
if (methodPC) return methodPC;
}
// realize, +initialize, and any special early exit
methodPC = prepareForMethodLookup(cls, sel, initialize, inst);
if (methodPC) return methodPC;
// The lock is held to make method-lookup + cache-fill atomic
// with respect to method addition. Otherwise, a category could
// be added but ignored indefinitely because the cache was re-filled
// with the old value after the cache flush on behalf of the category.
retry:
lockForMethodLookup();
// Ignore GC selectors
if (ignoreSelector(sel)) {
methodPC = _cache_addIgnoredEntry(cls, sel);
goto done;
}
// Try this class's cache.
methodPC = _cache_getImp(cls, sel);
if (methodPC) goto done;
// Try this class's method lists.
meth = _class_getMethodNoSuper_nolock(cls, sel);
if (meth) {
log_and_fill_cache(cls, cls, meth, sel);
methodPC = method_getImplementation(meth);
goto done;
}
// Try superclass caches and method lists.
curClass = cls;
while ((curClass = _class_getSuperclass(curClass))) {
// Superclass cache.
meth = _cache_getMethod(curClass, sel, _objc_msgForward_internal);
if (meth) {
if (meth != (Method)1) {
// Found the method in a superclass. Cache it in this class.
log_and_fill_cache(cls, curClass, meth, sel);
methodPC = method_getImplementation(meth);
goto done;
}
else {
// Found a forward:: entry in a superclass.
// Stop searching, but don't cache yet; call method
// resolver for this class first.
break;
}
}
// Superclass method list.
meth = _class_getMethodNoSuper_nolock(curClass, sel);
if (meth) {
log_and_fill_cache(cls, curClass, meth, sel);
methodPC = method_getImplementation(meth);
goto done;
}
}
// No implementation found. Try method resolver once.
if (!triedResolver) {
unlockForMethodLookup();
_class_resolveMethod(cls, sel);
// Don't cache the result; we don't hold the lock so it may have
// changed already. Re-do the search from scratch instead.
triedResolver = YES;
goto retry;
}
// No implementation found, and method resolver didn't help.
// Use forwarding.
_cache_addForwardEntry(cls, sel);
methodPC = _objc_msgForward_internal;
done:
unlockForMethodLookup();
// paranoia: look for ignored selectors with non-ignored implementations
assert(!(ignoreSelector(sel) && methodPC != (IMP)&_objc_ignored_method));
return methodPC;
}
/***********************************************************************
* lookupMethodInClassAndLoadCache.
* Like _class_lookupMethodAndLoadCache, but does not search superclasses.
* Caches and returns objc_msgForward if the method is not found in the class.
**********************************************************************/
static IMP lookupMethodInClassAndLoadCache(Class cls, SEL sel)
{
Method meth;
IMP imp;
// fixme this still has the method list vs method cache race
// because it doesn't hold a lock across lookup+cache_fill,
// but it's only used for .cxx_construct/destruct and we assume
// categories don't change them.
// Search cache first.
imp = _cache_getImp(cls, sel);
if (imp) return imp;
// Cache miss. Search method list.
meth = _class_getMethodNoSuper(cls, sel);
if (meth) {
// Hit in method list. Cache it.
_cache_fill(cls, meth, sel);
return method_getImplementation(meth);
} else {
// Miss in method list. Cache objc_msgForward.
_cache_addForwardEntry(cls, sel);
return _objc_msgForward_internal;
}
}
/***********************************************************************
* _malloc_internal
* _calloc_internal
* _realloc_internal
* _strdup_internal
* _strdupcat_internal
* _memdup_internal
* _free_internal
* Convenience functions for the internal malloc zone.
**********************************************************************/
void *_malloc_internal(size_t size)
{
return malloc_zone_malloc(_objc_internal_zone(), size);
}
void *_calloc_internal(size_t count, size_t size)
{
return malloc_zone_calloc(_objc_internal_zone(), count, size);
}
void *_realloc_internal(void *ptr, size_t size)
{
return malloc_zone_realloc(_objc_internal_zone(), ptr, size);
}
char *_strdup_internal(const char *str)
{
size_t len;
char *dup;
if (!str) return NULL;
len = strlen(str);
dup = (char *)malloc_zone_malloc(_objc_internal_zone(), len + 1);
memcpy(dup, str, len + 1);
return dup;
}
uint8_t *_ustrdup_internal(const uint8_t *str)
{
return (uint8_t *)_strdup_internal((char *)str);
}
// allocate a new string that concatenates s1+s2.
char *_strdupcat_internal(const char *s1, const char *s2)
{
size_t len1 = strlen(s1);
size_t len2 = strlen(s2);
char *dup = (char *)
malloc_zone_malloc(_objc_internal_zone(), len1 + len2 + 1);
memcpy(dup, s1, len1);
memcpy(dup + len1, s2, len2 + 1);
return dup;
}
void *_memdup_internal(const void *mem, size_t len)
{
void *dup = malloc_zone_malloc(_objc_internal_zone(), len);
memcpy(dup, mem, len);
return dup;
}
void _free_internal(void *ptr)
{
malloc_zone_free(_objc_internal_zone(), ptr);
}
size_t _malloc_size_internal(void *ptr)
{
malloc_zone_t *zone = _objc_internal_zone();
return zone->size(zone, ptr);
}
Class _calloc_class(size_t size)
{
#if SUPPORT_GC
if (UseGC) return (Class) malloc_zone_calloc(gc_zone, 1, size);
#endif
return (Class) _calloc_internal(1, size);
}
const char *class_getName(Class cls)
{
return _class_getName(cls);
}
Class class_getSuperclass(Class cls)
{
return _class_getSuperclass(cls);
}
BOOL class_isMetaClass(Class cls)
{
return _class_isMetaClass(cls);
}
size_t class_getInstanceSize(Class cls)
{
return _class_getInstanceSize(cls);
}
/***********************************************************************
* method_getNumberOfArguments.
**********************************************************************/
unsigned int method_getNumberOfArguments(Method m)
{
if (!m) return 0;
return encoding_getNumberOfArguments(method_getTypeEncoding(m));
}
void method_getReturnType(Method m, char *dst, size_t dst_len)
{
encoding_getReturnType(method_getTypeEncoding(m), dst, dst_len);
}
char * method_copyReturnType(Method m)
{
return encoding_copyReturnType(method_getTypeEncoding(m));
}
void method_getArgumentType(Method m, unsigned int index,
char *dst, size_t dst_len)
{
encoding_getArgumentType(method_getTypeEncoding(m),
index, dst, dst_len);
}
char * method_copyArgumentType(Method m, unsigned int index)
{
return encoding_copyArgumentType(method_getTypeEncoding(m), index);
}
/***********************************************************************
* objc_constructInstance
* Creates an instance of `cls` at the location pointed to by `bytes`.
* `bytes` must point to at least class_getInstanceSize(cls) bytes of
* well-aligned zero-filled memory.
* The new object's isa is set. Any C++ constructors are called.
* Returns `bytes` if successful. Returns nil if `cls` or `bytes` is
* NULL, or if C++ constructors fail.
* Note: class_createInstance() and class_createInstances() preflight this.
**********************************************************************/
static id
_objc_constructInstance(Class cls, void *bytes)
{
id obj = (id)bytes;
// Set the isa pointer
obj->isa = cls; // need not be object_setClass
// Call C++ constructors, if any.
if (!object_cxxConstruct(obj)) {
// Some C++ constructor threw an exception.
return nil;
}
return obj;
}
id
objc_constructInstance(Class cls, void *bytes)
{
if (!cls || !bytes) return nil;
return _objc_constructInstance(cls, bytes);
}
id
_objc_constructOrFree(Class cls, void *bytes)
{
id obj = _objc_constructInstance(cls, bytes);
if (!obj) {
#if SUPPORT_GC
if (UseGC) {
auto_zone_retain(gc_zone, bytes); // gc free expects rc==1
}
#endif
free(bytes);
}
return obj;
}
/***********************************************************************
* _class_createInstancesFromZone
* Batch-allocating version of _class_createInstanceFromZone.
* Attempts to allocate num_requested objects, each with extraBytes.
* Returns the number of allocated objects (possibly zero), with
* the allocated pointers in *results.
**********************************************************************/
unsigned
_class_createInstancesFromZone(Class cls, size_t extraBytes, void *zone,
id *results, unsigned num_requested)
{
unsigned num_allocated;
if (!cls) return 0;
size_t size = _class_getInstanceSize(cls) + extraBytes;
// CF requires all objects be at least 16 bytes.
if (size < 16) size = 16;
#if SUPPORT_GC
if (UseGC) {
num_allocated =
auto_zone_batch_allocate(gc_zone, size, AUTO_OBJECT_SCANNED, 0, 1,
(void**)results, num_requested);
} else
#endif
{
unsigned i;
num_allocated =
malloc_zone_batch_malloc((malloc_zone_t *)(zone ? zone : malloc_default_zone()),
size, (void**)results, num_requested);
for (i = 0; i < num_allocated; i++) {
bzero(results[i], size);
}
}
// Construct each object, and delete any that fail construction.
unsigned shift = 0;
unsigned i;
BOOL ctor = _class_hasCxxStructors(cls);
for (i = 0; i < num_allocated; i++) {
id obj = results[i];
if (ctor) obj = _objc_constructOrFree(cls, obj);
else if (obj) obj->isa = cls; // need not be object_setClass
if (obj) {
results[i-shift] = obj;
} else {
shift++;
}
}
return num_allocated - shift;
}
/***********************************************************************
* inform_duplicate. Complain about duplicate class implementations.
**********************************************************************/
void
inform_duplicate(const char *name, Class oldCls, Class cls)
{
#if TARGET_OS_WIN32
_objc_inform ("Class %s is implemented in two different images.", name);
#else
const header_info *oldHeader = _headerForClass(oldCls);
const header_info *newHeader = _headerForClass(cls);
const char *oldName = oldHeader ? oldHeader->fname : "??";
const char *newName = newHeader ? newHeader->fname : "??";
_objc_inform ("Class %s is implemented in both %s and %s. "
"One of the two will be used. "
"Which one is undefined.",
name, oldName, newName);
#endif
}
#if SUPPORT_TAGGED_POINTERS
/***********************************************************************
* _objc_insert_tagged_isa
* Insert an isa into a particular slot in the tagged isa table.
* Will error & abort if slot already has an isa that is different.
**********************************************************************/
void _objc_insert_tagged_isa(unsigned char slotNumber, Class isa) {
unsigned char actualSlotNumber = (slotNumber << 1) + 1;
Class previousIsa = _objc_tagged_isa_table[actualSlotNumber];
if (actualSlotNumber & 0xF0) {
_objc_fatal("%s -- Slot number %uc is too large. Aborting.", __FUNCTION__, slotNumber);
}
if (actualSlotNumber == 0) {
_objc_fatal("%s -- Slot number 0 doesn't make sense. Aborting.", __FUNCTION__);
}
if (isa && previousIsa && (previousIsa != isa)) {
_objc_fatal("%s -- Tagged pointer table already had an item in that slot (%s). "
"Not putting (%s) in table. Aborting instead",
__FUNCTION__, class_getName(previousIsa), class_getName(isa));
}
_objc_tagged_isa_table[actualSlotNumber] = isa;
}
#endif
const char *
copyPropertyAttributeString(const objc_property_attribute_t *attrs,
unsigned int count)
{
char *result;
unsigned int i;
if (count == 0) return strdup("");
#ifndef NDEBUG
// debug build: sanitize input
for (i = 0; i < count; i++) {
assert(attrs[i].name);
assert(strlen(attrs[i].name) > 0);
assert(! strchr(attrs[i].name, ','));
assert(! strchr(attrs[i].name, '"'));
if (attrs[i].value) assert(! strchr(attrs[i].value, ','));
}
#endif
size_t len = 0;
for (i = 0; i < count; i++) {
if (attrs[i].value) {
size_t namelen = strlen(attrs[i].name);
if (namelen > 1) namelen += 2; // long names get quoted
len += namelen + strlen(attrs[i].value) + 1;
}
}
result = (char *)malloc(len + 1);
char *s = result;
for (i = 0; i < count; i++) {
if (attrs[i].value) {
size_t namelen = strlen(attrs[i].name);
if (namelen > 1) {
s += sprintf(s, "\"%s\"%s,", attrs[i].name, attrs[i].value);
} else {
s += sprintf(s, "%s%s,", attrs[i].name, attrs[i].value);
}
}
}
// remove trailing ',' if any
if (s > result) s[-1] = '\0';
return result;
}
/*
Property attribute string format:
- Comma-separated name-value pairs.
- Name and value may not contain ,
- Name may not contain "
- Value may be empty
- Name is single char, value follows
- OR Name is double-quoted string of 2+ chars, value follows
Grammar:
attribute-string: \0
attribute-string: name-value-pair (',' name-value-pair)*
name-value-pair: unquoted-name optional-value
name-value-pair: quoted-name optional-value
unquoted-name: [^",]
quoted-name: '"' [^",]{2,} '"'
optional-value: [^,]*
*/
static unsigned int
iteratePropertyAttributes(const char *attrs,
BOOL (*fn)(unsigned int index,
void *ctx1, void *ctx2,
const char *name, size_t nlen,
const char *value, size_t vlen),
void *ctx1, void *ctx2)
{
if (!attrs) return 0;
#ifndef NDEBUG
const char *attrsend = attrs + strlen(attrs);
#endif
unsigned int attrcount = 0;
while (*attrs) {
// Find the next comma-separated attribute
const char *start = attrs;
const char *end = start + strcspn(attrs, ",");
// Move attrs past this attribute and the comma (if any)
attrs = *end ? end+1 : end;
assert(attrs <= attrsend);
assert(start <= attrsend);
assert(end <= attrsend);
// Skip empty attribute
if (start == end) continue;
// Process one non-empty comma-free attribute [start,end)
const char *nameStart;
const char *nameEnd;
assert(start < end);
assert(*start);
if (*start != '\"') {
// single-char short name
nameStart = start;
nameEnd = start+1;
start++;
}
else {
// double-quoted long name
nameStart = start+1;
nameEnd = nameStart + strcspn(nameStart, "\",");
start++; // leading quote
start += nameEnd - nameStart; // name
if (*start == '\"') start++; // trailing quote, if any
}
// Process one possibly-empty comma-free attribute value [start,end)
const char *valueStart;
const char *valueEnd;
assert(start <= end);
valueStart = start;
valueEnd = end;
BOOL more = (*fn)(attrcount, ctx1, ctx2,
nameStart, nameEnd-nameStart,
valueStart, valueEnd-valueStart);
attrcount++;
if (!more) break;
}
return attrcount;
}
static BOOL
copyOneAttribute(unsigned int index, void *ctxa, void *ctxs,
const char *name, size_t nlen, const char *value, size_t vlen)
{
objc_property_attribute_t **ap = (objc_property_attribute_t**)ctxa;
char **sp = (char **)ctxs;
objc_property_attribute_t *a = *ap;
char *s = *sp;
a->name = s;
memcpy(s, name, nlen);
s += nlen;
*s++ = '\0';
a->value = s;
memcpy(s, value, vlen);
s += vlen;
*s++ = '\0';
a++;
*ap = a;
*sp = s;
return YES;
}
objc_property_attribute_t *
copyPropertyAttributeList(const char *attrs, unsigned int *outCount)
{
if (!attrs) {
if (outCount) *outCount = 0;
return NULL;
}
// Result size:
// number of commas plus 1 for the attributes (upper bound)
// plus another attribute for the attribute array terminator
// plus strlen(attrs) for name/value string data (upper bound)
// plus count*2 for the name/value string terminators (upper bound)
unsigned int attrcount = 1;
const char *s;
for (s = attrs; s && *s; s++) {
if (*s == ',') attrcount++;
}
size_t size =
attrcount * sizeof(objc_property_attribute_t) +
sizeof(objc_property_attribute_t) +
strlen(attrs) +
attrcount * 2;
objc_property_attribute_t *result = (objc_property_attribute_t *)
calloc(size, 1);
objc_property_attribute_t *ra = result;
char *rs = (char *)(ra+attrcount+1);
attrcount = iteratePropertyAttributes(attrs, copyOneAttribute, &ra, &rs);
assert((uint8_t *)(ra+1) <= (uint8_t *)result+size);
assert((uint8_t *)rs <= (uint8_t *)result+size);
if (attrcount == 0) {
free(result);
result = NULL;
}
if (outCount) *outCount = attrcount;
return result;
}
static BOOL
findOneAttribute(unsigned int index, void *ctxa, void *ctxs,
const char *name, size_t nlen, const char *value, size_t vlen)
{
const char *query = (char *)ctxa;
char **resultp = (char **)ctxs;
if (strlen(query) == nlen && 0 == strncmp(name, query, nlen)) {
char *result = (char *)calloc(vlen+1, 1);
memcpy(result, value, vlen);
result[vlen] = '\0';
*resultp = result;
return NO;
}
return YES;
}
char *copyPropertyAttributeValue(const char *attrs, const char *name)
{
char *result = NULL;
iteratePropertyAttributes(attrs, findOneAttribute, (void*)name, &result);
return result;
}