NativeObject.h
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sts=4 et sw=4 tw=99:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef vm_NativeObject_h
#define vm_NativeObject_h
#include "mozilla/Assertions.h"
#include "mozilla/Attributes.h"
#include <stdint.h>
#include "jsfriendapi.h"
#include "jsobj.h"
#include "NamespaceImports.h"
#include "gc/Barrier.h"
#include "gc/Heap.h"
#include "gc/Marking.h"
#include "js/Value.h"
#include "vm/Shape.h"
#include "vm/ShapedObject.h"
#include "vm/String.h"
#include "vm/TypeInference.h"
namespace js {
class Shape;
class TenuringTracer;
/*
* To really poison a set of values, using 'magic' or 'undefined' isn't good
* enough since often these will just be ignored by buggy code (see bug 629974)
* in debug builds and crash in release builds. Instead, we use a safe-for-crash
* pointer.
*/
static MOZ_ALWAYS_INLINE void
Debug_SetValueRangeToCrashOnTouch(Value* beg, Value* end)
{
#ifdef DEBUG
for (Value* v = beg; v != end; ++v)
v->setObject(*reinterpret_cast<JSObject*>(0x48));
#endif
}
static MOZ_ALWAYS_INLINE void
Debug_SetValueRangeToCrashOnTouch(Value* vec, size_t len)
{
#ifdef DEBUG
Debug_SetValueRangeToCrashOnTouch(vec, vec + len);
#endif
}
static MOZ_ALWAYS_INLINE void
Debug_SetValueRangeToCrashOnTouch(GCPtrValue* vec, size_t len)
{
#ifdef DEBUG
Debug_SetValueRangeToCrashOnTouch((Value*) vec, len);
#endif
}
static MOZ_ALWAYS_INLINE void
Debug_SetSlotRangeToCrashOnTouch(HeapSlot* vec, uint32_t len)
{
#ifdef DEBUG
Debug_SetValueRangeToCrashOnTouch((Value*) vec, len);
#endif
}
static MOZ_ALWAYS_INLINE void
Debug_SetSlotRangeToCrashOnTouch(HeapSlot* begin, HeapSlot* end)
{
#ifdef DEBUG
Debug_SetValueRangeToCrashOnTouch((Value*) begin, end - begin);
#endif
}
class ArrayObject;
/*
* ES6 20130308 draft 8.4.2.4 ArraySetLength.
*
* |id| must be "length", |attrs| are the attributes to be used for the newly-
* changed length property, |value| is the value for the new length, and
* |result| receives an error code if the change is invalid.
*/
extern bool
ArraySetLength(JSContext* cx, Handle<ArrayObject*> obj, HandleId id,
unsigned attrs, HandleValue value, ObjectOpResult& result);
/*
* Elements header used for native objects. The elements component of such objects
* offers an efficient representation for all or some of the indexed properties
* of the object, using a flat array of Values rather than a shape hierarchy
* stored in the object's slots. This structure is immediately followed by an
* array of elements, with the elements member in an object pointing to the
* beginning of that array (the end of this structure).
* See below for usage of this structure.
*
* The sets of properties represented by an object's elements and slots
* are disjoint. The elements contain only indexed properties, while the slots
* can contain both named and indexed properties; any indexes in the slots are
* distinct from those in the elements. If isIndexed() is false for an object,
* all indexed properties (if any) are stored in the dense elements.
*
* Indexes will be stored in the object's slots instead of its elements in
* the following case:
* - there are more than MIN_SPARSE_INDEX slots total and the load factor
* (COUNT / capacity) is less than 0.25
* - a property is defined that has non-default property attributes.
*
* We track these pieces of metadata for dense elements:
* - The length property as a uint32_t, accessible for array objects with
* ArrayObject::{length,setLength}(). This is unused for non-arrays.
* - The number of element slots (capacity), gettable with
* getDenseCapacity().
* - The array's initialized length, accessible with
* getDenseInitializedLength().
*
* Holes in the array are represented by MagicValue(JS_ELEMENTS_HOLE) values.
* These indicate indexes which are not dense properties of the array. The
* property may, however, be held by the object's properties.
*
* The capacity and length of an object's elements are almost entirely
* unrelated! In general the length may be greater than, less than, or equal
* to the capacity. The first case occurs with |new Array(100)|. The length
* is 100, but the capacity remains 0 (indices below length and above capacity
* must be treated as holes) until elements between capacity and length are
* set. The other two cases are common, depending upon the number of elements
* in an array and the underlying allocator used for element storage.
*
* The only case in which the capacity and length of an object's elements are
* related is when the object is an array with non-writable length. In this
* case the capacity is always less than or equal to the length. This permits
* JIT code to optimize away the check for non-writable length when assigning
* to possibly out-of-range elements: such code already has to check for
* |index < capacity|, and fallback code checks for non-writable length.
*
* The initialized length of an object specifies the number of elements that
* have been initialized. All elements above the initialized length are
* holes in the object, and the memory for all elements between the initialized
* length and capacity is left uninitialized. The initialized length is some
* value less than or equal to both the object's length and the object's
* capacity.
*
* There is flexibility in exactly the value the initialized length must hold,
* e.g. if an array has length 5, capacity 10, completely empty, it is valid
* for the initialized length to be any value between zero and 5, as long as
* the in memory values below the initialized length have been initialized with
* a hole value. However, in such cases we want to keep the initialized length
* as small as possible: if the object is known to have no hole values below
* its initialized length, then it is "packed" and can be accessed much faster
* by JIT code.
*
* Elements do not track property creation order, so enumerating the elements
* of an object does not necessarily visit indexes in the order they were
* created.
*/
class ObjectElements
{
public:
enum Flags: uint32_t {
// Integers written to these elements must be converted to doubles.
CONVERT_DOUBLE_ELEMENTS = 0x1,
// Present only if these elements correspond to an array with
// non-writable length; never present for non-arrays.
NONWRITABLE_ARRAY_LENGTH = 0x2,
// These elements are shared with another object and must be copied
// before they can be changed. A pointer to the original owner of the
// elements, which is immutable, is stored immediately after the
// elements data. There is one case where elements can be written to
// before being copied: when setting the CONVERT_DOUBLE_ELEMENTS flag
// the shared elements may change (from ints to doubles) without
// making a copy first.
COPY_ON_WRITE = 0x4,
// For TypedArrays only: this TypedArray's storage is mapping shared
// memory. This is a static property of the TypedArray, set when it
// is created and never changed.
SHARED_MEMORY = 0x8,
// These elements are set to integrity level "frozen".
FROZEN = 0x10,
};
private:
friend class ::JSObject;
friend class ArrayObject;
friend class NativeObject;
friend class TenuringTracer;
friend bool js::SetIntegrityLevel(JSContext* cx, HandleObject obj, IntegrityLevel level);
friend bool
ArraySetLength(JSContext* cx, Handle<ArrayObject*> obj, HandleId id,
unsigned attrs, HandleValue value, ObjectOpResult& result);
/* See Flags enum above. */
uint32_t flags;
/*
* Number of initialized elements. This is <= the capacity, and for arrays
* is <= the length. Memory for elements above the initialized length is
* uninitialized, but values between the initialized length and the proper
* length are conceptually holes.
*/
uint32_t initializedLength;
/* Number of allocated slots. */
uint32_t capacity;
/* 'length' property of array objects, unused for other objects. */
uint32_t length;
bool shouldConvertDoubleElements() const {
return flags & CONVERT_DOUBLE_ELEMENTS;
}
void setShouldConvertDoubleElements() {
// Note: allow isCopyOnWrite() here, see comment above.
flags |= CONVERT_DOUBLE_ELEMENTS;
}
void clearShouldConvertDoubleElements() {
MOZ_ASSERT(!isCopyOnWrite());
flags &= ~CONVERT_DOUBLE_ELEMENTS;
}
bool hasNonwritableArrayLength() const {
return flags & NONWRITABLE_ARRAY_LENGTH;
}
void setNonwritableArrayLength() {
MOZ_ASSERT(!isCopyOnWrite());
flags |= NONWRITABLE_ARRAY_LENGTH;
}
bool isCopyOnWrite() const {
return flags & COPY_ON_WRITE;
}
void clearCopyOnWrite() {
MOZ_ASSERT(isCopyOnWrite());
flags &= ~COPY_ON_WRITE;
}
public:
constexpr ObjectElements(uint32_t capacity, uint32_t length)
: flags(0), initializedLength(0), capacity(capacity), length(length)
{}
enum class SharedMemory {
IsShared
};
constexpr ObjectElements(uint32_t capacity, uint32_t length, SharedMemory shmem)
: flags(SHARED_MEMORY), initializedLength(0), capacity(capacity), length(length)
{}
HeapSlot* elements() {
return reinterpret_cast<HeapSlot*>(uintptr_t(this) + sizeof(ObjectElements));
}
const HeapSlot* elements() const {
return reinterpret_cast<const HeapSlot*>(uintptr_t(this) + sizeof(ObjectElements));
}
static ObjectElements * fromElements(HeapSlot* elems) {
return reinterpret_cast<ObjectElements*>(uintptr_t(elems) - sizeof(ObjectElements));
}
bool isSharedMemory() const {
return flags & SHARED_MEMORY;
}
GCPtrNativeObject& ownerObject() const {
MOZ_ASSERT(isCopyOnWrite());
return *(GCPtrNativeObject*)(&elements()[initializedLength]);
}
static int offsetOfFlags() {
return int(offsetof(ObjectElements, flags)) - int(sizeof(ObjectElements));
}
static int offsetOfInitializedLength() {
return int(offsetof(ObjectElements, initializedLength)) - int(sizeof(ObjectElements));
}
static int offsetOfCapacity() {
return int(offsetof(ObjectElements, capacity)) - int(sizeof(ObjectElements));
}
static int offsetOfLength() {
return int(offsetof(ObjectElements, length)) - int(sizeof(ObjectElements));
}
static bool ConvertElementsToDoubles(JSContext* cx, uintptr_t elements);
static bool MakeElementsCopyOnWrite(ExclusiveContext* cx, NativeObject* obj);
static bool FreezeElements(ExclusiveContext* cx, HandleNativeObject obj);
bool isFrozen() const {
return flags & FROZEN;
}
void freeze() {
MOZ_ASSERT(!isFrozen());
MOZ_ASSERT(!isCopyOnWrite());
flags |= FROZEN;
}
void markNotFrozen() {
MOZ_ASSERT(isFrozen());
MOZ_ASSERT(!isCopyOnWrite());
flags &= ~FROZEN;
}
uint8_t elementAttributes() const {
if (isFrozen())
return JSPROP_ENUMERATE | JSPROP_PERMANENT | JSPROP_READONLY;
return JSPROP_ENUMERATE;
}
// This is enough slots to store an object of this class. See the static
// assertion below.
static const size_t VALUES_PER_HEADER = 2;
};
static_assert(ObjectElements::VALUES_PER_HEADER * sizeof(HeapSlot) == sizeof(ObjectElements),
"ObjectElements doesn't fit in the given number of slots");
/*
* Shared singletons for objects with no elements.
* emptyObjectElementsShared is used only for TypedArrays, when the TA
* maps shared memory.
*/
extern HeapSlot* const emptyObjectElements;
extern HeapSlot* const emptyObjectElementsShared;
struct Class;
class GCMarker;
class Shape;
class NewObjectCache;
#ifdef DEBUG
static inline bool
IsObjectValueInCompartment(const Value& v, JSCompartment* comp);
#endif
// Operations which change an object's dense elements can either succeed, fail,
// or be unable to complete. For native objects, the latter is used when the
// object's elements must become sparse instead. The enum below is used for
// such operations, and for similar operations on unboxed arrays and methods
// that work on both kinds of objects.
enum class DenseElementResult {
Failure,
Success,
Incomplete
};
/*
* NativeObject specifies the internal implementation of a native object.
*
* Native objects use ShapedObject::shape_ to record property information. Two
* native objects with the same shape are guaranteed to have the same number of
* fixed slots.
*
* Native objects extend the base implementation of an object with storage for
* the object's named properties and indexed elements.
*
* These are stored separately from one another. Objects are followed by a
* variable-sized array of values for inline storage, which may be used by
* either properties of native objects (fixed slots), by elements (fixed
* elements), or by other data for certain kinds of objects, such as
* ArrayBufferObjects and TypedArrayObjects.
*
* Named property storage can be split between fixed slots and a dynamically
* allocated array (the slots member). For an object with N fixed slots, shapes
* with slots [0..N-1] are stored in the fixed slots, and the remainder are
* stored in the dynamic array. If all properties fit in the fixed slots, the
* 'slots_' member is nullptr.
*
* Elements are indexed via the 'elements_' member. This member can point to
* either the shared emptyObjectElements and emptyObjectElementsShared singletons,
* into the inline value array (the address of the third value, to leave room
* for a ObjectElements header;in this case numFixedSlots() is zero) or to
* a dynamically allocated array.
*
* Slots and elements may both be non-empty. The slots may be either names or
* indexes; no indexed property will be in both the slots and elements.
*/
class NativeObject : public ShapedObject
{
protected:
/* Slots for object properties. */
js::HeapSlot* slots_;
/* Slots for object dense elements. */
js::HeapSlot* elements_;
friend class ::JSObject;
private:
static void staticAsserts() {
static_assert(sizeof(NativeObject) == sizeof(JSObject_Slots0),
"native object size must match GC thing size");
static_assert(sizeof(NativeObject) == sizeof(shadow::Object),
"shadow interface must match actual implementation");
static_assert(sizeof(NativeObject) % sizeof(Value) == 0,
"fixed slots after an object must be aligned");
static_assert(offsetof(NativeObject, group_) == offsetof(shadow::Object, group),
"shadow type must match actual type");
static_assert(offsetof(NativeObject, slots_) == offsetof(shadow::Object, slots),
"shadow slots must match actual slots");
static_assert(offsetof(NativeObject, elements_) == offsetof(shadow::Object, _1),
"shadow placeholder must match actual elements");
static_assert(MAX_FIXED_SLOTS <= Shape::FIXED_SLOTS_MAX,
"verify numFixedSlots() bitfield is big enough");
static_assert(sizeof(NativeObject) + MAX_FIXED_SLOTS * sizeof(Value) == JSObject::MAX_BYTE_SIZE,
"inconsistent maximum object size");
}
public:
Shape* lastProperty() const {
MOZ_ASSERT(shape_);
return shape_;
}
uint32_t propertyCount() const {
return lastProperty()->entryCount();
}
bool hasShapeTable() const {
return lastProperty()->hasTable();
}
HeapSlotArray getDenseElements() {
return HeapSlotArray(elements_, !getElementsHeader()->isCopyOnWrite());
}
HeapSlotArray getDenseElementsAllowCopyOnWrite() {
// Backdoor allowing direct access to copy on write elements.
return HeapSlotArray(elements_, true);
}
const Value& getDenseElement(uint32_t idx) const {
MOZ_ASSERT(idx < getDenseInitializedLength());
return elements_[idx];
}
bool containsDenseElement(uint32_t idx) {
return idx < getDenseInitializedLength() && !elements_[idx].isMagic(JS_ELEMENTS_HOLE);
}
uint32_t getDenseInitializedLength() const {
return getElementsHeader()->initializedLength;
}
uint32_t getDenseCapacity() const {
return getElementsHeader()->capacity;
}
bool isSharedMemory() const {
return getElementsHeader()->isSharedMemory();
}
// Update the last property, keeping the number of allocated slots in sync
// with the object's new slot span.
bool setLastProperty(ExclusiveContext* cx, Shape* shape);
// As for setLastProperty(), but allows the number of fixed slots to
// change. This can only be used when fixed slots are being erased from the
// object, and only when the object will not require dynamic slots to cover
// the new properties.
void setLastPropertyShrinkFixedSlots(Shape* shape);
// As for setLastProperty(), but changes the class associated with the
// object to a non-native one. This leaves the object with a type and shape
// that are (temporarily) inconsistent.
void setLastPropertyMakeNonNative(Shape* shape);
// As for setLastProperty(), but changes the class associated with the
// object to a native one. The object's type has already been changed, and
// this brings the shape into sync with it.
void setLastPropertyMakeNative(ExclusiveContext* cx, Shape* shape);
// Newly-created TypedArrays that map a SharedArrayBuffer are
// marked as shared by giving them an ObjectElements that has the
// ObjectElements::SHARED_MEMORY flag set.
void setIsSharedMemory() {
MOZ_ASSERT(elements_ == emptyObjectElements);
elements_ = emptyObjectElementsShared;
}
bool isInWholeCellBuffer() const {
const gc::TenuredCell* cell = &asTenured();
gc::ArenaCellSet* cells = cell->arena()->bufferedCells;
return cells && cells->hasCell(cell);
}
protected:
#ifdef DEBUG
void checkShapeConsistency();
#else
void checkShapeConsistency() { }
#endif
Shape*
replaceWithNewEquivalentShape(ExclusiveContext* cx,
Shape* existingShape, Shape* newShape = nullptr,
bool accessorShape = false);
/*
* Remove the last property of an object, provided that it is safe to do so
* (the shape and previous shape do not carry conflicting information about
* the object itself).
*/
inline void removeLastProperty(ExclusiveContext* cx);
inline bool canRemoveLastProperty();
/*
* Update the slot span directly for a dictionary object, and allocate
* slots to cover the new span if necessary.
*/
bool setSlotSpan(ExclusiveContext* cx, uint32_t span);
bool toDictionaryMode(ExclusiveContext* cx);
private:
friend class TenuringTracer;
/*
* Get internal pointers to the range of values starting at start and
* running for length.
*/
void getSlotRangeUnchecked(uint32_t start, uint32_t length,
HeapSlot** fixedStart, HeapSlot** fixedEnd,
HeapSlot** slotsStart, HeapSlot** slotsEnd)
{
MOZ_ASSERT(start + length >= start);
uint32_t fixed = numFixedSlots();
if (start < fixed) {
if (start + length < fixed) {
*fixedStart = &fixedSlots()[start];
*fixedEnd = &fixedSlots()[start + length];
*slotsStart = *slotsEnd = nullptr;
} else {
uint32_t localCopy = fixed - start;
*fixedStart = &fixedSlots()[start];
*fixedEnd = &fixedSlots()[start + localCopy];
*slotsStart = &slots_[0];
*slotsEnd = &slots_[length - localCopy];
}
} else {
*fixedStart = *fixedEnd = nullptr;
*slotsStart = &slots_[start - fixed];
*slotsEnd = &slots_[start - fixed + length];
}
}
void getSlotRange(uint32_t start, uint32_t length,
HeapSlot** fixedStart, HeapSlot** fixedEnd,
HeapSlot** slotsStart, HeapSlot** slotsEnd)
{
MOZ_ASSERT(slotInRange(start + length, SENTINEL_ALLOWED));
getSlotRangeUnchecked(start, length, fixedStart, fixedEnd, slotsStart, slotsEnd);
}
protected:
friend class GCMarker;
friend class Shape;
friend class NewObjectCache;
void invalidateSlotRange(uint32_t start, uint32_t length) {
#ifdef DEBUG
HeapSlot* fixedStart;
HeapSlot* fixedEnd;
HeapSlot* slotsStart;
HeapSlot* slotsEnd;
getSlotRange(start, length, &fixedStart, &fixedEnd, &slotsStart, &slotsEnd);
Debug_SetSlotRangeToCrashOnTouch(fixedStart, fixedEnd);
Debug_SetSlotRangeToCrashOnTouch(slotsStart, slotsEnd);
#endif /* DEBUG */
}
void initializeSlotRange(uint32_t start, uint32_t count);
/*
* Initialize a flat array of slots to this object at a start slot. The
* caller must ensure that are enough slots.
*/
void initSlotRange(uint32_t start, const Value* vector, uint32_t length);
/*
* Copy a flat array of slots to this object at a start slot. Caller must
* ensure there are enough slots in this object.
*/
void copySlotRange(uint32_t start, const Value* vector, uint32_t length);
#ifdef DEBUG
enum SentinelAllowed {
SENTINEL_NOT_ALLOWED,
SENTINEL_ALLOWED
};
/*
* Check that slot is in range for the object's allocated slots.
* If sentinelAllowed then slot may equal the slot capacity.
*/
bool slotInRange(uint32_t slot, SentinelAllowed sentinel = SENTINEL_NOT_ALLOWED) const;
#endif
/*
* Minimum size for dynamically allocated slots in normal Objects.
* ArrayObjects don't use this limit and can have a lower slot capacity,
* since they normally don't have a lot of slots.
*/
static const uint32_t SLOT_CAPACITY_MIN = 8;
HeapSlot* fixedSlots() const {
return reinterpret_cast<HeapSlot*>(uintptr_t(this) + sizeof(NativeObject));
}
public:
bool generateOwnShape(ExclusiveContext* cx, Shape* newShape = nullptr) {
return replaceWithNewEquivalentShape(cx, lastProperty(), newShape);
}
bool shadowingShapeChange(ExclusiveContext* cx, const Shape& shape);
bool clearFlag(ExclusiveContext* cx, BaseShape::Flag flag);
// The maximum number of slots in an object.
// |MAX_SLOTS_COUNT * sizeof(JS::Value)| shouldn't overflow
// int32_t (see slotsSizeMustNotOverflow).
static const uint32_t MAX_SLOTS_COUNT = (1 << 28) - 1;
static void slotsSizeMustNotOverflow() {
static_assert(NativeObject::MAX_SLOTS_COUNT <= INT32_MAX / sizeof(JS::Value),
"every caller of this method requires that a slot "
"number (or slot count) count multiplied by "
"sizeof(Value) can't overflow uint32_t (and sometimes "
"int32_t, too)");
}
uint32_t numFixedSlots() const {
return reinterpret_cast<const shadow::Object*>(this)->numFixedSlots();
}
uint32_t numUsedFixedSlots() const {
uint32_t nslots = lastProperty()->slotSpan(getClass());
return Min(nslots, numFixedSlots());
}
uint32_t numFixedSlotsForCompilation() const;
uint32_t slotSpan() const {
if (inDictionaryMode())
return lastProperty()->base()->slotSpan();
return lastProperty()->slotSpan();
}
/* Whether a slot is at a fixed offset from this object. */
bool isFixedSlot(size_t slot) {
return slot < numFixedSlots();
}
/* Index into the dynamic slots array to use for a dynamic slot. */
size_t dynamicSlotIndex(size_t slot) {
MOZ_ASSERT(slot >= numFixedSlots());
return slot - numFixedSlots();
}
/*
* Grow or shrink slots immediately before changing the slot span.
* The number of allocated slots is not stored explicitly, and changes to
* the slots must track changes in the slot span.
*/
bool growSlots(ExclusiveContext* cx, uint32_t oldCount, uint32_t newCount);
void shrinkSlots(ExclusiveContext* cx, uint32_t oldCount, uint32_t newCount);
/*
* This method is static because it's called from JIT code. On OOM, returns
* false without leaving a pending exception on the context.
*/
static bool growSlotsDontReportOOM(ExclusiveContext* cx, NativeObject* obj, uint32_t newCount);
bool hasDynamicSlots() const { return !!slots_; }
/* Compute dynamicSlotsCount() for this object. */
uint32_t numDynamicSlots() const {
return dynamicSlotsCount(numFixedSlots(), slotSpan(), getClass());
}
bool empty() const {
return lastProperty()->isEmptyShape();
}
Shape* lookup(ExclusiveContext* cx, jsid id);
Shape* lookup(ExclusiveContext* cx, PropertyName* name) {
return lookup(cx, NameToId(name));
}
bool contains(ExclusiveContext* cx, jsid id) {
return lookup(cx, id) != nullptr;
}
bool contains(ExclusiveContext* cx, PropertyName* name) {
return lookup(cx, name) != nullptr;
}
bool contains(ExclusiveContext* cx, Shape* shape) {
return lookup(cx, shape->propid()) == shape;
}
bool containsShapeOrElement(ExclusiveContext* cx, jsid id) {
if (JSID_IS_INT(id) && containsDenseElement(JSID_TO_INT(id)))
return true;
return contains(cx, id);
}
/* Contextless; can be called from other pure code. */
Shape* lookupPure(jsid id);
Shape* lookupPure(PropertyName* name) {
return lookupPure(NameToId(name));
}
bool containsPure(jsid id) {
return lookupPure(id) != nullptr;
}
bool containsPure(PropertyName* name) {
return containsPure(NameToId(name));
}
bool containsPure(Shape* shape) {
return lookupPure(shape->propid()) == shape;
}
/*
* Allocate and free an object slot.
*
* FIXME: bug 593129 -- slot allocation should be done by object methods
* after calling object-parameter-free shape methods, avoiding coupling
* logic across the object vs. shape module wall.
*/
static bool allocSlot(ExclusiveContext* cx, HandleNativeObject obj, uint32_t* slotp);
void freeSlot(ExclusiveContext* cx, uint32_t slot);
private:
static Shape* getChildPropertyOnDictionary(ExclusiveContext* cx, HandleNativeObject obj,
HandleShape parent, MutableHandle<StackShape> child);
static Shape* getChildProperty(ExclusiveContext* cx, HandleNativeObject obj,
HandleShape parent, MutableHandle<StackShape> child);
public:
/* Add a property whose id is not yet in this scope. */
static Shape* addProperty(ExclusiveContext* cx, HandleNativeObject obj, HandleId id,
JSGetterOp getter, JSSetterOp setter,
uint32_t slot, unsigned attrs, unsigned flags,
bool allowDictionary = true);
/* Add a data property whose id is not yet in this scope. */
Shape* addDataProperty(ExclusiveContext* cx,
jsid id_, uint32_t slot, unsigned attrs);
Shape* addDataProperty(ExclusiveContext* cx, HandlePropertyName name,
uint32_t slot, unsigned attrs);
/* Add or overwrite a property for id in this scope. */
static Shape*
putProperty(ExclusiveContext* cx, HandleNativeObject obj, HandleId id,
JSGetterOp getter, JSSetterOp setter,
uint32_t slot, unsigned attrs,
unsigned flags);
static inline Shape*
putProperty(ExclusiveContext* cx, HandleObject obj, PropertyName* name,
JSGetterOp getter, JSSetterOp setter,
uint32_t slot, unsigned attrs,
unsigned flags);
/* Change the given property into a sibling with the same id in this scope. */
static Shape*
changeProperty(ExclusiveContext* cx, HandleNativeObject obj, HandleShape shape,
unsigned attrs, JSGetterOp getter, JSSetterOp setter);
/* Remove the property named by id from this object. */
bool removeProperty(ExclusiveContext* cx, jsid id);
/* Clear the scope, making it empty. */
static void clear(ExclusiveContext* cx, HandleNativeObject obj);
protected:
/*
* Internal helper that adds a shape not yet mapped by this object.
*
* Notes:
* 1. getter and setter must be normalized based on flags (see jsscope.cpp).
* 2. Checks for non-extensibility must be done by callers.
*/
static Shape*
addPropertyInternal(ExclusiveContext* cx, HandleNativeObject obj, HandleId id,
JSGetterOp getter, JSSetterOp setter, uint32_t slot, unsigned attrs,
unsigned flags, ShapeTable::Entry* entry, bool allowDictionary,
const AutoKeepShapeTables& keep);
bool fillInAfterSwap(JSContext* cx, const Vector<Value>& values, void* priv);
public:
// Return true if this object has been converted from shared-immutable
// prototype-rooted shape storage to dictionary-shapes in a doubly-linked
// list.
bool inDictionaryMode() const {
return lastProperty()->inDictionary();
}
const Value& getSlot(uint32_t slot) const {
MOZ_ASSERT(slotInRange(slot));
uint32_t fixed = numFixedSlots();
if (slot < fixed)
return fixedSlots()[slot];
return slots_[slot - fixed];
}
const HeapSlot* getSlotAddressUnchecked(uint32_t slot) const {
uint32_t fixed = numFixedSlots();
if (slot < fixed)
return fixedSlots() + slot;
return slots_ + (slot - fixed);
}
HeapSlot* getSlotAddressUnchecked(uint32_t slot) {
uint32_t fixed = numFixedSlots();
if (slot < fixed)
return fixedSlots() + slot;
return slots_ + (slot - fixed);
}
HeapSlot* getSlotAddress(uint32_t slot) {
/*
* This can be used to get the address of the end of the slots for the
* object, which may be necessary when fetching zero-length arrays of
* slots (e.g. for callObjVarArray).
*/
MOZ_ASSERT(slotInRange(slot, SENTINEL_ALLOWED));
return getSlotAddressUnchecked(slot);
}
const HeapSlot* getSlotAddress(uint32_t slot) const {
/*
* This can be used to get the address of the end of the slots for the
* object, which may be necessary when fetching zero-length arrays of
* slots (e.g. for callObjVarArray).
*/
MOZ_ASSERT(slotInRange(slot, SENTINEL_ALLOWED));
return getSlotAddressUnchecked(slot);
}
HeapSlot& getSlotRef(uint32_t slot) {
MOZ_ASSERT(slotInRange(slot));
return *getSlotAddress(slot);
}
const HeapSlot& getSlotRef(uint32_t slot) const {
MOZ_ASSERT(slotInRange(slot));
return *getSlotAddress(slot);
}
void setSlot(uint32_t slot, const Value& value) {
MOZ_ASSERT(slotInRange(slot));
MOZ_ASSERT(IsObjectValueInCompartment(value, compartment()));
getSlotRef(slot).set(this, HeapSlot::Slot, slot, value);
}
void initSlot(uint32_t slot, const Value& value) {
MOZ_ASSERT(getSlot(slot).isUndefined());
MOZ_ASSERT(slotInRange(slot));
MOZ_ASSERT(IsObjectValueInCompartment(value, compartment()));
initSlotUnchecked(slot, value);
}
void initSlotUnchecked(uint32_t slot, const Value& value) {
getSlotAddressUnchecked(slot)->init(this, HeapSlot::Slot, slot, value);
}
// MAX_FIXED_SLOTS is the biggest number of fixed slots our GC
// size classes will give an object.
static const uint32_t MAX_FIXED_SLOTS = 16;
protected:
inline bool updateSlotsForSpan(ExclusiveContext* cx, size_t oldSpan, size_t newSpan);
private:
void prepareElementRangeForOverwrite(size_t start, size_t end) {
MOZ_ASSERT(end <= getDenseInitializedLength());
MOZ_ASSERT(!denseElementsAreCopyOnWrite());
for (size_t i = start; i < end; i++)
elements_[i].HeapSlot::~HeapSlot();
}
/*
* Trigger the write barrier on a range of slots that will no longer be
* reachable.
*/
void prepareSlotRangeForOverwrite(size_t start, size_t end) {
for (size_t i = start; i < end; i++)
getSlotAddressUnchecked(i)->HeapSlot::~HeapSlot();
}
public:
static bool rollbackProperties(ExclusiveContext* cx, HandleNativeObject obj,
uint32_t slotSpan);
inline void setSlotWithType(ExclusiveContext* cx, Shape* shape,
const Value& value, bool overwriting = true);
inline const Value& getReservedSlot(uint32_t index) const {
MOZ_ASSERT(index < JSSLOT_FREE(getClass()));
return getSlot(index);
}
const HeapSlot& getReservedSlotRef(uint32_t index) const {
MOZ_ASSERT(index < JSSLOT_FREE(getClass()));
return getSlotRef(index);
}
HeapSlot& getReservedSlotRef(uint32_t index) {
MOZ_ASSERT(index < JSSLOT_FREE(getClass()));
return getSlotRef(index);
}
void initReservedSlot(uint32_t index, const Value& v) {
MOZ_ASSERT(index < JSSLOT_FREE(getClass()));
initSlot(index, v);
}
void setReservedSlot(uint32_t index, const Value& v) {
MOZ_ASSERT(index < JSSLOT_FREE(getClass()));
setSlot(index, v);
}
/* For slots which are known to always be fixed, due to the way they are allocated. */
HeapSlot& getFixedSlotRef(uint32_t slot) {
MOZ_ASSERT(slot < numFixedSlots());
return fixedSlots()[slot];
}
const Value& getFixedSlot(uint32_t slot) const {
MOZ_ASSERT(slot < numFixedSlots());
return fixedSlots()[slot];
}
void setFixedSlot(uint32_t slot, const Value& value) {
MOZ_ASSERT(slot < numFixedSlots());
fixedSlots()[slot].set(this, HeapSlot::Slot, slot, value);
}
void initFixedSlot(uint32_t slot, const Value& value) {
MOZ_ASSERT(slot < numFixedSlots());
fixedSlots()[slot].init(this, HeapSlot::Slot, slot, value);
}
/*
* Get the number of dynamic slots to allocate to cover the properties in
* an object with the given number of fixed slots and slot span. The slot
* capacity is not stored explicitly, and the allocated size of the slot
* array is kept in sync with this count.
*/
static uint32_t dynamicSlotsCount(uint32_t nfixed, uint32_t span, const Class* clasp);
static uint32_t dynamicSlotsCount(Shape* shape) {
return dynamicSlotsCount(shape->numFixedSlots(), shape->slotSpan(), shape->getObjectClass());
}
/* Elements accessors. */
// The maximum size, in sizeof(Value), of the allocation used for an
// object's dense elements. (This includes space used to store an
// ObjectElements instance.)
// |MAX_DENSE_ELEMENTS_ALLOCATION * sizeof(JS::Value)| shouldn't overflow
// int32_t (see elementsSizeMustNotOverflow).
static const uint32_t MAX_DENSE_ELEMENTS_ALLOCATION = (1 << 28) - 1;
// The maximum number of usable dense elements in an object.
static const uint32_t MAX_DENSE_ELEMENTS_COUNT =
MAX_DENSE_ELEMENTS_ALLOCATION - ObjectElements::VALUES_PER_HEADER;
static void elementsSizeMustNotOverflow() {
static_assert(NativeObject::MAX_DENSE_ELEMENTS_COUNT <= INT32_MAX / sizeof(JS::Value),
"every caller of this method require that an element "
"count multiplied by sizeof(Value) can't overflow "
"uint32_t (and sometimes int32_t ,too)");
}
ObjectElements * getElementsHeader() const {
return ObjectElements::fromElements(elements_);
}
/* Accessors for elements. */
bool ensureElements(ExclusiveContext* cx, uint32_t capacity) {
MOZ_ASSERT(!denseElementsAreCopyOnWrite());
MOZ_ASSERT(!denseElementsAreFrozen());
if (capacity > getDenseCapacity())
return growElements(cx, capacity);
return true;
}
static bool goodElementsAllocationAmount(ExclusiveContext* cx, uint32_t reqAllocated,
uint32_t length, uint32_t* goodAmount);
bool growElements(ExclusiveContext* cx, uint32_t newcap);
void shrinkElements(ExclusiveContext* cx, uint32_t cap);
void setDynamicElements(ObjectElements* header) {
MOZ_ASSERT(!hasDynamicElements());
elements_ = header->elements();
MOZ_ASSERT(hasDynamicElements());
}
static bool CopyElementsForWrite(ExclusiveContext* cx, NativeObject* obj);
bool maybeCopyElementsForWrite(ExclusiveContext* cx) {
if (denseElementsAreCopyOnWrite())
return CopyElementsForWrite(cx, this);
return true;
}
private:
inline void ensureDenseInitializedLengthNoPackedCheck(ExclusiveContext* cx,
uint32_t index, uint32_t extra);
// Run a post write barrier that encompasses multiple contiguous elements in a
// single step.
inline void elementsRangeWriteBarrierPost(uint32_t start, uint32_t count) {
for (size_t i = 0; i < count; i++) {
const Value& v = elements_[start + i];
if (v.isObject() && IsInsideNursery(&v.toObject())) {
JS::shadow::Runtime* shadowRuntime = shadowRuntimeFromMainThread();
shadowRuntime->gcStoreBufferPtr()->putSlot(this, HeapSlot::Element,
start + i, count - i);
return;
}
}
}
// See the comment over setDenseElementUnchecked, this applies in the same way.
void setDenseInitializedLengthUnchecked(uint32_t length) {
MOZ_ASSERT(length <= getDenseCapacity());
MOZ_ASSERT(!denseElementsAreCopyOnWrite());
prepareElementRangeForOverwrite(length, getElementsHeader()->initializedLength);
getElementsHeader()->initializedLength = length;
}
// Use this function with care. This is done to allow sparsifying frozen
// objects, but should only be called in a few places, and should be
// audited carefully!
void setDenseElementUnchecked(uint32_t index, const Value& val) {
MOZ_ASSERT(index < getDenseInitializedLength());
MOZ_ASSERT(!denseElementsAreCopyOnWrite());
elements_[index].set(this, HeapSlot::Element, index, val);
}
public:
void setDenseInitializedLength(uint32_t length) {
MOZ_ASSERT(!denseElementsAreFrozen());
setDenseInitializedLengthUnchecked(length);
}
inline void ensureDenseInitializedLength(ExclusiveContext* cx,
uint32_t index, uint32_t extra);
void setDenseElement(uint32_t index, const Value& val) {
MOZ_ASSERT(!denseElementsAreFrozen());
setDenseElementUnchecked(index, val);
}
void initDenseElement(uint32_t index, const Value& val) {
MOZ_ASSERT(index < getDenseInitializedLength());
MOZ_ASSERT(!denseElementsAreCopyOnWrite());
MOZ_ASSERT(!denseElementsAreFrozen());
elements_[index].init(this, HeapSlot::Element, index, val);
}
void setDenseElementMaybeConvertDouble(uint32_t index, const Value& val) {
if (val.isInt32() && shouldConvertDoubleElements())
setDenseElement(index, DoubleValue(val.toInt32()));
else
setDenseElement(index, val);
}
inline void setDenseElementWithType(ExclusiveContext* cx, uint32_t index,
const Value& val);
inline void initDenseElementWithType(ExclusiveContext* cx, uint32_t index,
const Value& val);
inline void setDenseElementHole(ExclusiveContext* cx, uint32_t index);
static inline void removeDenseElementForSparseIndex(ExclusiveContext* cx,
HandleNativeObject obj, uint32_t index);
inline Value getDenseOrTypedArrayElement(uint32_t idx);
void copyDenseElements(uint32_t dstStart, const Value* src, uint32_t count) {
MOZ_ASSERT(dstStart + count <= getDenseCapacity());
MOZ_ASSERT(!denseElementsAreCopyOnWrite());
MOZ_ASSERT(!denseElementsAreFrozen());
if (JS::shadow::Zone::asShadowZone(zone())->needsIncrementalBarrier()) {
for (uint32_t i = 0; i < count; ++i)
elements_[dstStart + i].set(this, HeapSlot::Element, dstStart + i, src[i]);
} else {
memcpy(&elements_[dstStart], src, count * sizeof(HeapSlot));
elementsRangeWriteBarrierPost(dstStart, count);
}
}
void initDenseElements(uint32_t dstStart, const Value* src, uint32_t count) {
MOZ_ASSERT(dstStart + count <= getDenseCapacity());
MOZ_ASSERT(!denseElementsAreCopyOnWrite());
MOZ_ASSERT(!denseElementsAreFrozen());
memcpy(&elements_[dstStart], src, count * sizeof(HeapSlot));
elementsRangeWriteBarrierPost(dstStart, count);
}
void moveDenseElements(uint32_t dstStart, uint32_t srcStart, uint32_t count) {
MOZ_ASSERT(dstStart + count <= getDenseCapacity());
MOZ_ASSERT(srcStart + count <= getDenseInitializedLength());
MOZ_ASSERT(!denseElementsAreCopyOnWrite());
MOZ_ASSERT(!denseElementsAreFrozen());
/*
* Using memmove here would skip write barriers. Also, we need to consider
* an array containing [A, B, C], in the following situation:
*
* 1. Incremental GC marks slot 0 of array (i.e., A), then returns to JS code.
* 2. JS code moves slots 1..2 into slots 0..1, so it contains [B, C, C].
* 3. Incremental GC finishes by marking slots 1 and 2 (i.e., C).
*
* Since normal marking never happens on B, it is very important that the
* write barrier is invoked here on B, despite the fact that it exists in
* the array before and after the move.
*/
if (JS::shadow::Zone::asShadowZone(zone())->needsIncrementalBarrier()) {
if (dstStart < srcStart) {
HeapSlot* dst = elements_ + dstStart;
HeapSlot* src = elements_ + srcStart;
for (uint32_t i = 0; i < count; i++, dst++, src++)
dst->set(this, HeapSlot::Element, dst - elements_, *src);
} else {
HeapSlot* dst = elements_ + dstStart + count - 1;
HeapSlot* src = elements_ + srcStart + count - 1;
for (uint32_t i = 0; i < count; i++, dst--, src--)
dst->set(this, HeapSlot::Element, dst - elements_, *src);
}
} else {
memmove(elements_ + dstStart, elements_ + srcStart, count * sizeof(HeapSlot));
elementsRangeWriteBarrierPost(dstStart, count);
}
}
void moveDenseElementsNoPreBarrier(uint32_t dstStart, uint32_t srcStart, uint32_t count) {
MOZ_ASSERT(!shadowZone()->needsIncrementalBarrier());
MOZ_ASSERT(dstStart + count <= getDenseCapacity());
MOZ_ASSERT(srcStart + count <= getDenseCapacity());
MOZ_ASSERT(!denseElementsAreCopyOnWrite());
MOZ_ASSERT(!denseElementsAreFrozen());
memmove(elements_ + dstStart, elements_ + srcStart, count * sizeof(Value));
elementsRangeWriteBarrierPost(dstStart, count);
}
bool shouldConvertDoubleElements() {
return getElementsHeader()->shouldConvertDoubleElements();
}
inline void setShouldConvertDoubleElements();
inline void clearShouldConvertDoubleElements();
bool denseElementsAreCopyOnWrite() {
return getElementsHeader()->isCopyOnWrite();
}
bool denseElementsAreFrozen() {
return getElementsHeader()->isFrozen();
}
/* Packed information for this object's elements. */
inline bool writeToIndexWouldMarkNotPacked(uint32_t index);
inline void markDenseElementsNotPacked(ExclusiveContext* cx);
// Ensures that the object can hold at least index + extra elements. This
// returns DenseElement_Success on success, DenseElement_Failed on failure
// to grow the array, or DenseElement_Incomplete when the object is too
// sparse to grow (this includes the case of index + extra overflow). In
// the last two cases the object is kept intact.
inline DenseElementResult ensureDenseElements(ExclusiveContext* cx,
uint32_t index, uint32_t extra);
inline DenseElementResult extendDenseElements(ExclusiveContext* cx,
uint32_t requiredCapacity, uint32_t extra);
/* Convert a single dense element to a sparse property. */
static bool sparsifyDenseElement(ExclusiveContext* cx,
HandleNativeObject obj, uint32_t index);
/* Convert all dense elements to sparse properties. */
static bool sparsifyDenseElements(ExclusiveContext* cx, HandleNativeObject obj);
/* Small objects are dense, no matter what. */
static const uint32_t MIN_SPARSE_INDEX = 1000;
/*
* Element storage for an object will be sparse if fewer than 1/8 indexes
* are filled in.
*/
static const unsigned SPARSE_DENSITY_RATIO = 8;
/*
* Check if after growing the object's elements will be too sparse.
* newElementsHint is an estimated number of elements to be added.
*/
bool willBeSparseElements(uint32_t requiredCapacity, uint32_t newElementsHint);
/*
* After adding a sparse index to obj, see if it should be converted to use
* dense elements.
*/
static DenseElementResult maybeDensifySparseElements(ExclusiveContext* cx,
HandleNativeObject obj);
inline HeapSlot* fixedElements() const {
static_assert(2 * sizeof(Value) == sizeof(ObjectElements),
"when elements are stored inline, the first two "
"slots will hold the ObjectElements header");
return &fixedSlots()[2];
}
#ifdef DEBUG
bool canHaveNonEmptyElements();
#endif
void setFixedElements() {
MOZ_ASSERT(canHaveNonEmptyElements());
elements_ = fixedElements();
}
inline bool hasDynamicElements() const {
/*
* Note: for objects with zero fixed slots this could potentially give
* a spurious 'true' result, if the end of this object is exactly
* aligned with the end of its arena and dynamic slots are allocated
* immediately afterwards. Such cases cannot occur for dense arrays
* (which have at least two fixed slots) and can only result in a leak.
*/
return !hasEmptyElements() && elements_ != fixedElements();
}
inline bool hasFixedElements() const {
return elements_ == fixedElements();
}
inline bool hasEmptyElements() const {
return elements_ == emptyObjectElements || elements_ == emptyObjectElementsShared;
}
/*
* Get a pointer to the unused data in the object's allocation immediately
* following this object, for use with objects which allocate a larger size
* class than they need and store non-elements data inline.
*/
inline uint8_t* fixedData(size_t nslots) const;
inline void privateWriteBarrierPre(void** oldval);
void privateWriteBarrierPost(void** pprivate) {
gc::Cell** cellp = reinterpret_cast<gc::Cell**>(pprivate);
MOZ_ASSERT(cellp);
MOZ_ASSERT(*cellp);
gc::StoreBuffer* storeBuffer = (*cellp)->storeBuffer();
if (storeBuffer)
storeBuffer->putCell(cellp);
}
/* Private data accessors. */
inline void*& privateRef(uint32_t nfixed) const { /* XXX should be private, not protected! */
/*
* The private pointer of an object can hold any word sized value.
* Private pointers are stored immediately after the last fixed slot of
* the object.
*/
MOZ_ASSERT(nfixed == numFixedSlots());
MOZ_ASSERT(hasPrivate());
HeapSlot* end = &fixedSlots()[nfixed];
return *reinterpret_cast<void**>(end);
}
bool hasPrivate() const {
return getClass()->hasPrivate();
}
void* getPrivate() const {
return privateRef(numFixedSlots());
}
void setPrivate(void* data) {
void** pprivate = &privateRef(numFixedSlots());
privateWriteBarrierPre(pprivate);
*pprivate = data;
}
void setPrivateGCThing(gc::Cell* cell) {
void** pprivate = &privateRef(numFixedSlots());
privateWriteBarrierPre(pprivate);
*pprivate = reinterpret_cast<void*>(cell);
privateWriteBarrierPost(pprivate);
}
void setPrivateUnbarriered(void* data) {
void** pprivate = &privateRef(numFixedSlots());
*pprivate = data;
}
void initPrivate(void* data) {
privateRef(numFixedSlots()) = data;
}
/* Access private data for an object with a known number of fixed slots. */
inline void* getPrivate(uint32_t nfixed) const {
return privateRef(nfixed);
}
static inline NativeObject*
copy(ExclusiveContext* cx, gc::AllocKind kind, gc::InitialHeap heap,
HandleNativeObject templateObject);
void updateShapeAfterMovingGC();
void sweepDictionaryListPointer();
/* JIT Accessors */
static size_t offsetOfElements() { return offsetof(NativeObject, elements_); }
static size_t offsetOfFixedElements() {
return sizeof(NativeObject) + sizeof(ObjectElements);
}
static size_t getFixedSlotOffset(size_t slot) {
return sizeof(NativeObject) + slot * sizeof(Value);
}
static size_t getPrivateDataOffset(size_t nfixed) { return getFixedSlotOffset(nfixed); }
static size_t offsetOfSlots() { return offsetof(NativeObject, slots_); }
};
// Object class for plain native objects created using '{}' object literals,
// 'new Object()', 'Object.create', etc.
class PlainObject : public NativeObject
{
public:
static const js::Class class_;
};
inline void
NativeObject::privateWriteBarrierPre(void** oldval)
{
JS::shadow::Zone* shadowZone = this->shadowZoneFromAnyThread();
if (shadowZone->needsIncrementalBarrier() && *oldval && getClass()->hasTrace())
getClass()->doTrace(shadowZone->barrierTracer(), this);
}
#ifdef DEBUG
static inline bool
IsObjectValueInCompartment(const Value& v, JSCompartment* comp)
{
if (!v.isObject())
return true;
return v.toObject().compartment() == comp;
}
#endif
/*** Standard internal methods *******************************************************************/
/*
* These functions should follow the algorithms in ES6 draft rev 29 section 9.1
* ("Ordinary Object Internal Methods"). It's an ongoing project.
*
* Many native objects are not "ordinary" in ES6, so these functions also have
* to serve some of the special needs of Functions (9.2, 9.3, 9.4.1), Arrays
* (9.4.2), Strings (9.4.3), and so on.
*/
extern bool
NativeDefineProperty(ExclusiveContext* cx, HandleNativeObject obj, HandleId id,
Handle<JS::PropertyDescriptor> desc,
ObjectOpResult& result);
extern bool
NativeDefineProperty(ExclusiveContext* cx, HandleNativeObject obj, HandleId id, HandleValue value,
JSGetterOp getter, JSSetterOp setter, unsigned attrs,
ObjectOpResult& result);
extern bool
NativeDefineProperty(ExclusiveContext* cx, HandleNativeObject obj, PropertyName* name,
HandleValue value, GetterOp getter, SetterOp setter,
unsigned attrs, ObjectOpResult& result);
extern bool
NativeDefineElement(ExclusiveContext* cx, HandleNativeObject obj, uint32_t index, HandleValue value,
JSGetterOp getter, JSSetterOp setter, unsigned attrs,
ObjectOpResult& result);
/* If the result out-param is omitted, throw on failure. */
extern bool
NativeDefineProperty(ExclusiveContext* cx, HandleNativeObject obj, HandleId id, HandleValue value,
JSGetterOp getter, JSSetterOp setter, unsigned attrs);
extern bool
NativeDefineProperty(ExclusiveContext* cx, HandleNativeObject obj, PropertyName* name,
HandleValue value, JSGetterOp getter, JSSetterOp setter,
unsigned attrs);
extern bool
NativeHasProperty(JSContext* cx, HandleNativeObject obj, HandleId id, bool* foundp);
extern bool
NativeGetOwnPropertyDescriptor(JSContext* cx, HandleNativeObject obj, HandleId id,
MutableHandle<JS::PropertyDescriptor> desc);
extern bool
NativeGetProperty(JSContext* cx, HandleNativeObject obj, HandleValue receiver, HandleId id,
MutableHandleValue vp);
extern bool
NativeGetPropertyNoGC(JSContext* cx, NativeObject* obj, const Value& receiver, jsid id, Value* vp);
inline bool
NativeGetProperty(JSContext* cx, HandleNativeObject obj, HandleId id, MutableHandleValue vp)
{
RootedValue receiver(cx, ObjectValue(*obj));
return NativeGetProperty(cx, obj, receiver, id, vp);
}
bool
SetPropertyByDefining(JSContext* cx, HandleId id, HandleValue v, HandleValue receiver,
ObjectOpResult& result);
bool
SetPropertyOnProto(JSContext* cx, HandleObject obj, HandleId id, HandleValue v,
HandleValue receiver, ObjectOpResult& result);
/*
* Indicates whether an assignment operation is qualified (`x.y = 0`) or
* unqualified (`y = 0`). In strict mode, the latter is an error if no such
* variable already exists.
*
* Used as an argument to NativeSetProperty.
*/
enum QualifiedBool {
Unqualified = 0,
Qualified = 1
};
extern bool
NativeSetProperty(JSContext* cx, HandleNativeObject obj, HandleId id, HandleValue v,
HandleValue receiver, QualifiedBool qualified, ObjectOpResult& result);
extern bool
NativeSetElement(JSContext* cx, HandleNativeObject obj, uint32_t index, HandleValue v,
HandleValue receiver, ObjectOpResult& result);
extern bool
NativeDeleteProperty(JSContext* cx, HandleNativeObject obj, HandleId id, ObjectOpResult& result);
/*** SpiderMonkey nonstandard internal methods ***************************************************/
template <AllowGC allowGC>
extern bool
NativeLookupOwnProperty(ExclusiveContext* cx,
typename MaybeRooted<NativeObject*, allowGC>::HandleType obj,
typename MaybeRooted<jsid, allowGC>::HandleType id,
typename MaybeRooted<Shape*, allowGC>::MutableHandleType propp);
/*
* Get a property from `receiver`, after having already done a lookup and found
* the property on a native object `obj`.
*
* `shape` must not be null and must not be an implicit dense property. It must
* be present in obj's shape chain.
*/
extern bool
NativeGetExistingProperty(JSContext* cx, HandleObject receiver, HandleNativeObject obj,
HandleShape shape, MutableHandleValue vp);
/* * */
/*
* If obj has an already-resolved data property for id, return true and
* store the property value in *vp.
*/
extern bool
HasDataProperty(JSContext* cx, NativeObject* obj, jsid id, Value* vp);
inline bool
HasDataProperty(JSContext* cx, NativeObject* obj, PropertyName* name, Value* vp)
{
return HasDataProperty(cx, obj, NameToId(name), vp);
}
extern bool
GetPropertyForNameLookup(JSContext* cx, HandleObject obj, HandleId id, MutableHandleValue vp);
} /* namespace js */
template <>
inline bool
JSObject::is<js::NativeObject>() const { return isNative(); }
namespace js {
// Alternate to JSObject::as<NativeObject>() that tolerates null pointers.
inline NativeObject*
MaybeNativeObject(JSObject* obj)
{
return obj ? &obj->as<NativeObject>() : nullptr;
}
// Defined in NativeObject-inl.h.
bool IsPackedArray(JSObject* obj);
} // namespace js
/*** Inline functions declared in jsobj.h that use the native declarations above *****************/
inline bool
js::HasProperty(JSContext* cx, HandleObject obj, HandleId id, bool* foundp)
{
if (HasPropertyOp op = obj->getOpsHasProperty())
return op(cx, obj, id, foundp);
return NativeHasProperty(cx, obj.as<NativeObject>(), id, foundp);
}
inline bool
js::GetProperty(JSContext* cx, HandleObject obj, HandleValue receiver, HandleId id,
MutableHandleValue vp)
{
if (GetPropertyOp op = obj->getOpsGetProperty())
return op(cx, obj, receiver, id, vp);
return NativeGetProperty(cx, obj.as<NativeObject>(), receiver, id, vp);
}
inline bool
js::GetPropertyNoGC(JSContext* cx, JSObject* obj, const Value& receiver, jsid id, Value* vp)
{
if (obj->getOpsGetProperty())
return false;
return NativeGetPropertyNoGC(cx, &obj->as<NativeObject>(), receiver, id, vp);
}
inline bool
js::SetProperty(JSContext* cx, HandleObject obj, HandleId id, HandleValue v,
HandleValue receiver, ObjectOpResult& result)
{
if (obj->getOpsSetProperty())
return JSObject::nonNativeSetProperty(cx, obj, id, v, receiver, result);
return NativeSetProperty(cx, obj.as<NativeObject>(), id, v, receiver, Qualified, result);
}
inline bool
js::SetElement(JSContext* cx, HandleObject obj, uint32_t index, HandleValue v,
HandleValue receiver, ObjectOpResult& result)
{
if (obj->getOpsSetProperty())
return JSObject::nonNativeSetElement(cx, obj, index, v, receiver, result);
return NativeSetElement(cx, obj.as<NativeObject>(), index, v, receiver, result);
}
#endif /* vm_NativeObject_h */
