/*
* Copyright (c) 2006-2008 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@
*/
#include <string.h>
#include <stddef.h>
#include <libkern/OSAtomic.h>
#include "objc-private.h"
#include "objc-auto.h"
#include "runtime.h"
#include "objc-accessors.h"
// stub interface declarations to make compiler happy.
@interface __NSCopyable
- (id)copyWithZone:(void *)zone;
@end
@interface __NSMutableCopyable
- (id)mutableCopyWithZone:(void *)zone;
@end
typedef uintptr_t spin_lock_t;
OBJC_EXTERN void _spin_lock(spin_lock_t *lockp);
OBJC_EXTERN int _spin_lock_try(spin_lock_t *lockp);
OBJC_EXTERN void _spin_unlock(spin_lock_t *lockp);
/* need to consider cache line contention - space locks out XXX */
#define GOODPOWER 7
#define GOODMASK ((1<<GOODPOWER)-1)
#define GOODHASH(x) (((long)x >> 5) & GOODMASK)
static spin_lock_t PropertyLocks[1 << GOODPOWER] = { 0 };
#define MUTABLE_COPY 2
id objc_getProperty_non_gc(id self, SEL _cmd, ptrdiff_t offset, BOOL atomic) {
// Retain release world
id *slot = (id*) ((char*)self + offset);
if (!atomic) return *slot;
// Atomic retain release world
spin_lock_t *slotlock = &PropertyLocks[GOODHASH(slot)];
_spin_lock(slotlock);
id value = objc_retain(*slot);
_spin_unlock(slotlock);
// for performance, we (safely) issue the autorelease OUTSIDE of the spinlock.
return objc_autoreleaseReturnValue(value);
}
static inline void reallySetProperty(id self, SEL _cmd, id newValue, ptrdiff_t offset, bool atomic, bool copy, bool mutableCopy) __attribute__((always_inline));
static inline void reallySetProperty(id self, SEL _cmd, id newValue, ptrdiff_t offset, bool atomic, bool copy, bool mutableCopy)
{
id oldValue;
id *slot = (id*) ((char*)self + offset);
if (copy) {
newValue = [newValue copyWithZone:NULL];
} else if (mutableCopy) {
newValue = [newValue mutableCopyWithZone:NULL];
} else {
if (*slot == newValue) return;
newValue = objc_retain(newValue);
}
if (!atomic) {
oldValue = *slot;
*slot = newValue;
} else {
spin_lock_t *slotlock = &PropertyLocks[GOODHASH(slot)];
_spin_lock(slotlock);
oldValue = *slot;
*slot = newValue;
_spin_unlock(slotlock);
}
objc_release(oldValue);
}
void objc_setProperty_non_gc(id self, SEL _cmd, ptrdiff_t offset, id newValue, BOOL atomic, signed char shouldCopy)
{
bool copy = (shouldCopy && shouldCopy != MUTABLE_COPY);
bool mutableCopy = (shouldCopy == MUTABLE_COPY);
reallySetProperty(self, _cmd, newValue, offset, atomic, copy, mutableCopy);
}
void objc_setProperty_atomic(id self, SEL _cmd, id newValue, ptrdiff_t offset)
{
reallySetProperty(self, _cmd, newValue, offset, true, false, false);
}
void objc_setProperty_nonatomic(id self, SEL _cmd, id newValue, ptrdiff_t offset)
{
reallySetProperty(self, _cmd, newValue, offset, false, false, false);
}
void objc_setProperty_atomic_copy(id self, SEL _cmd, id newValue, ptrdiff_t offset)
{
reallySetProperty(self, _cmd, newValue, offset, true, true, false);
}
void objc_setProperty_nonatomic_copy(id self, SEL _cmd, id newValue, ptrdiff_t offset)
{
reallySetProperty(self, _cmd, newValue, offset, false, true, false);
}
#if SUPPORT_GC
id objc_getProperty_gc(id self, SEL _cmd, ptrdiff_t offset, BOOL atomic) {
return *(id*) ((char*)self + offset);
}
void objc_setProperty_gc(id self, SEL _cmd, ptrdiff_t offset, id newValue, BOOL atomic, signed char shouldCopy) {
if (shouldCopy) {
newValue = (shouldCopy == MUTABLE_COPY ? [newValue mutableCopyWithZone:NULL] : [newValue copyWithZone:NULL]);
}
objc_assign_ivar(newValue, self, offset);
}
// objc_getProperty and objc_setProperty are resolver functions in objc-auto.mm
#else
id
objc_getProperty(id self, SEL _cmd, ptrdiff_t offset, BOOL atomic)
{
return objc_getProperty_non_gc(self, _cmd, offset, atomic);
}
void
objc_setProperty(id self, SEL _cmd, ptrdiff_t offset, id newValue,
BOOL atomic, signed char shouldCopy)
{
objc_setProperty_non_gc(self, _cmd, offset, newValue, atomic, shouldCopy);
}
#endif
// This entry point was designed wrong. When used as a getter, src needs to be locked so that
// if simultaneously used for a setter then there would be contention on src.
// So we need two locks - one of which will be contended.
void objc_copyStruct(void *dest, const void *src, ptrdiff_t size, BOOL atomic, BOOL hasStrong) {
static spin_lock_t StructLocks[1 << GOODPOWER] = { 0 };
spin_lock_t *lockfirst = NULL;
spin_lock_t *locksecond = NULL;
if (atomic) {
lockfirst = &StructLocks[GOODHASH(src)];
locksecond = &StructLocks[GOODHASH(dest)];
// order the locks by address so that we don't deadlock
if (lockfirst > locksecond) {
lockfirst = locksecond;
locksecond = &StructLocks[GOODHASH(src)];
}
else if (lockfirst == locksecond) {
// lucky - we only need one lock
locksecond = NULL;
}
_spin_lock(lockfirst);
if (locksecond) _spin_lock(locksecond);
}
#if SUPPORT_GC
if (UseGC && hasStrong) {
auto_zone_write_barrier_memmove(gc_zone, dest, src, size);
} else
#endif
{
memmove(dest, src, size);
}
if (atomic) {
_spin_unlock(lockfirst);
if (locksecond) _spin_unlock(locksecond);
}
}
void objc_copyCppObjectAtomic(void *dest, const void *src, void (*copyHelper) (void *dest, const void *source)) {
static spin_lock_t CppObjectLocks[1 << GOODPOWER] = { 0 };
spin_lock_t *lockfirst = &CppObjectLocks[GOODHASH(src)], *locksecond = &CppObjectLocks[GOODHASH(dest)];
// order the locks by address so that we don't deadlock
if (lockfirst > locksecond) {
spin_lock_t *temp = lockfirst;
lockfirst = locksecond;
locksecond = temp;
} else if (lockfirst == locksecond) {
// lucky - we only need one lock
locksecond = NULL;
}
_spin_lock(lockfirst);
if (locksecond) _spin_lock(locksecond);
// let C++ code perform the actual copy.
copyHelper(dest, src);
_spin_unlock(lockfirst);
if (locksecond) _spin_unlock(locksecond);
}