mozilla-central/js/src/vm/JSObject.cpp (file symbol)

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
* 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/. */
/*
* JS object implementation.
*/
#include "vm/JSObject-inl.h"
#include "mozilla/MemoryReporting.h"
#include "mozilla/Try.h"
#include <string.h>
#include "jsapi.h"
#include "jsdate.h"
#include "jsexn.h"
#include "jsfriendapi.h"
#include "jsnum.h"
#include "jstypes.h"
#include "builtin/BigInt.h"
#include "builtin/MapObject.h"
#include "builtin/Object.h"
#include "builtin/String.h"
#include "builtin/Symbol.h"
#include "builtin/WeakSetObject.h"
#include "gc/AllocKind.h"
#include "gc/GC.h"
#include "js/CharacterEncoding.h"
#include "js/friend/DumpFunctions.h" // js::DumpObject
#include "js/friend/ErrorMessages.h" // JSErrNum, js::GetErrorMessage, JSMSG_*
#include "js/friend/WindowProxy.h" // js::IsWindow, js::ToWindowProxyIfWindow
#include "js/MemoryMetrics.h"
#include "js/Prefs.h" // JS::Prefs
#include "js/Printer.h" // js::GenericPrinter, js::Fprinter
#include "js/PropertyDescriptor.h" // JS::FromPropertyDescriptor
#include "js/PropertySpec.h" // JSPropertySpec
#include "js/Proxy.h"
#include "js/Result.h"
#include "js/UbiNode.h"
#include "js/Wrapper.h"
#include "proxy/DeadObjectProxy.h"
#include "util/Memory.h"
#include "util/Text.h"
#include "util/WindowsWrapper.h"
#include "vm/ArgumentsObject.h"
#include "vm/ArrayBufferObject.h"
#include "vm/ArrayBufferViewObject.h"
#include "vm/BytecodeUtil.h"
#include "vm/Compartment.h"
#include "vm/DateObject.h"
#include "vm/Interpreter.h"
#include "vm/Iteration.h"
#include "vm/JSAtomUtils.h" // Atomize
#include "vm/JSContext.h"
#include "vm/JSFunction.h"
#include "vm/JSONPrinter.h" // js::JSONPrinter
#include "vm/JSScript.h"
#include "vm/PromiseObject.h"
#include "vm/ProxyObject.h"
#include "vm/RegExpObject.h"
#include "vm/SelfHosting.h"
#include "vm/Shape.h"
#include "vm/TypedArrayObject.h"
#include "vm/Watchtower.h"
#include "vm/WrapperObject.h"
#ifdef ENABLE_RECORD_TUPLE
# include "builtin/RecordObject.h"
# include "builtin/TupleObject.h"
# include "vm/RecordType.h"
# include "vm/TupleType.h"
#endif
#include "gc/StableCellHasher-inl.h"
#include "vm/BooleanObject-inl.h"
#include "vm/EnvironmentObject-inl.h"
#include "vm/Interpreter-inl.h"
#include "vm/JSAtomUtils-inl.h" // AtomToId, PrimitiveValueToId, IndexToId
#include "vm/JSContext-inl.h"
#include "vm/NativeObject-inl.h"
#include "vm/NumberObject-inl.h"
#include "vm/ObjectFlags-inl.h"
#include "vm/Realm-inl.h"
#include "vm/StringObject-inl.h"
#include "vm/TypedArrayObject-inl.h"
#include "wasm/WasmGcObject-inl.h"
using namespace js;
using mozilla::Maybe;
void js::ReportNotObject(JSContext* cx, JSErrNum err, int spindex,
HandleValue v) {
MOZ_ASSERT(!v.isObject());
ReportValueError(cx, err, spindex, v, nullptr);
}
void js::ReportNotObject(JSContext* cx, JSErrNum err, HandleValue v) {
ReportNotObject(cx, err, JSDVG_SEARCH_STACK, v);
}
void js::ReportNotObject(JSContext* cx, const Value& v) {
RootedValue value(cx, v);
ReportNotObject(cx, JSMSG_OBJECT_REQUIRED, value);
}
void js::ReportNotObjectArg(JSContext* cx, const char* nth, const char* fun,
HandleValue v) {
MOZ_ASSERT(!v.isObject());
UniqueChars bytes;
const char* chars = ValueToSourceForError(cx, v, bytes);
MOZ_ASSERT(chars);
JS_ReportErrorNumberLatin1(cx, GetErrorMessage, nullptr,
JSMSG_OBJECT_REQUIRED_ARG, nth, fun, chars);
}
JS_PUBLIC_API const char* JS::InformalValueTypeName(const Value& v) {
switch (v.type()) {
case ValueType::Double:
case ValueType::Int32:
return "number";
case ValueType::Boolean:
return "boolean";
case ValueType::Undefined:
return "undefined";
case ValueType::Null:
return "null";
case ValueType::String:
return "string";
case ValueType::Symbol:
return "symbol";
case ValueType::BigInt:
return "bigint";
case ValueType::Object:
#ifdef ENABLE_RECORD_TUPLE
case ValueType::ExtendedPrimitive:
#endif
return v.getObjectPayload().getClass()->name;
case ValueType::Magic:
return "magic";
case ValueType::PrivateGCThing:
break;
}
MOZ_CRASH("unexpected type");
}
// ES6 draft rev37 6.2.4.4 FromPropertyDescriptor
JS_PUBLIC_API bool JS::FromPropertyDescriptor(
JSContext* cx, Handle<Maybe<PropertyDescriptor>> desc_,
MutableHandleValue vp) {
AssertHeapIsIdle();
CHECK_THREAD(cx);
cx->check(desc_);
// Step 1.
if (desc_.isNothing()) {
vp.setUndefined();
return true;
}
Rooted<PropertyDescriptor> desc(cx, *desc_);
return FromPropertyDescriptorToObject(cx, desc, vp);
}
bool js::FromPropertyDescriptorToObject(JSContext* cx,
Handle<PropertyDescriptor> desc,
MutableHandleValue vp) {
// Step 2-3.
RootedObject obj(cx, NewPlainObject(cx));
if (!obj) {
return false;
}
const JSAtomState& names = cx->names();
// Step 4.
if (desc.hasValue()) {
if (!DefineDataProperty(cx, obj, names.value, desc.value())) {
return false;
}
}
// Step 5.
RootedValue v(cx);
if (desc.hasWritable()) {
v.setBoolean(desc.writable());
if (!DefineDataProperty(cx, obj, names.writable, v)) {
return false;
}
}
// Step 6.
if (desc.hasGetter()) {
if (JSObject* get = desc.getter()) {
v.setObject(*get);
} else {
v.setUndefined();
}
if (!DefineDataProperty(cx, obj, names.get, v)) {
return false;
}
}
// Step 7.
if (desc.hasSetter()) {
if (JSObject* set = desc.setter()) {
v.setObject(*set);
} else {
v.setUndefined();
}
if (!DefineDataProperty(cx, obj, names.set, v)) {
return false;
}
}
// Step 8.
if (desc.hasEnumerable()) {
v.setBoolean(desc.enumerable());
if (!DefineDataProperty(cx, obj, names.enumerable, v)) {
return false;
}
}
// Step 9.
if (desc.hasConfigurable()) {
v.setBoolean(desc.configurable());
if (!DefineDataProperty(cx, obj, names.configurable, v)) {
return false;
}
}
vp.setObject(*obj);
return true;
}
bool js::GetFirstArgumentAsObject(JSContext* cx, const CallArgs& args,
const char* method,
MutableHandleObject objp) {
if (!args.requireAtLeast(cx, method, 1)) {
return false;
}
HandleValue v = args[0];
if (!v.isObject()) {
UniqueChars bytes =
DecompileValueGenerator(cx, JSDVG_SEARCH_STACK, v, nullptr);
if (!bytes) {
return false;
}
JS_ReportErrorNumberUTF8(cx, GetErrorMessage, nullptr,
JSMSG_UNEXPECTED_TYPE, bytes.get(),
"not an object");
return false;
}
objp.set(&v.toObject());
return true;
}
static bool GetPropertyIfPresent(JSContext* cx, HandleObject obj, HandleId id,
MutableHandleValue vp, bool* foundp) {
if (!HasProperty(cx, obj, id, foundp)) {
return false;
}
if (!*foundp) {
vp.setUndefined();
return true;
}
return GetProperty(cx, obj, obj, id, vp);
}
bool js::Throw(JSContext* cx, HandleId id, unsigned errorNumber,
const char* details) {
MOZ_ASSERT(js_ErrorFormatString[errorNumber].argCount == (details ? 2 : 1));
MOZ_ASSERT_IF(details, JS::StringIsASCII(details));
UniqueChars bytes =
IdToPrintableUTF8(cx, id, IdToPrintableBehavior::IdIsPropertyKey);
if (!bytes) {
return false;
}
if (details) {
JS_ReportErrorNumberUTF8(cx, GetErrorMessage, nullptr, errorNumber,
bytes.get(), details);
} else {
JS_ReportErrorNumberUTF8(cx, GetErrorMessage, nullptr, errorNumber,
bytes.get());
}
return false;
}
/*** PropertyDescriptor operations and DefineProperties *********************/
static Result<> CheckCallable(JSContext* cx, JSObject* obj,
const char* fieldName) {
if (obj && !obj->isCallable()) {
JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr,
JSMSG_BAD_GET_SET_FIELD, fieldName);
return cx->alreadyReportedError();
}
return Ok();
}
// 6.2.5.5 ToPropertyDescriptor(Obj)
bool js::ToPropertyDescriptor(JSContext* cx, HandleValue descval,
bool checkAccessors,
MutableHandle<PropertyDescriptor> desc_) {
// Step 1.
RootedObject obj(cx,
RequireObject(cx, JSMSG_OBJECT_REQUIRED_PROP_DESC, descval));
if (!obj) {
return false;
}
// Step 2.
Rooted<PropertyDescriptor> desc(cx, PropertyDescriptor::Empty());
RootedId id(cx);
RootedValue v(cx);
// Steps 3-4.
id = NameToId(cx->names().enumerable);
bool hasEnumerable = false;
if (!GetPropertyIfPresent(cx, obj, id, &v, &hasEnumerable)) {
return false;
}
if (hasEnumerable) {
desc.setEnumerable(ToBoolean(v));
}
// Steps 5-6.
id = NameToId(cx->names().configurable);
bool hasConfigurable = false;
if (!GetPropertyIfPresent(cx, obj, id, &v, &hasConfigurable)) {
return false;
}
if (hasConfigurable) {
desc.setConfigurable(ToBoolean(v));
}
// Steps 7-8.
id = NameToId(cx->names().value);
bool hasValue = false;
if (!GetPropertyIfPresent(cx, obj, id, &v, &hasValue)) {
return false;
}
if (hasValue) {
desc.setValue(v);
}
// Steps 9-10.
id = NameToId(cx->names().writable);
bool hasWritable = false;
if (!GetPropertyIfPresent(cx, obj, id, &v, &hasWritable)) {
return false;
}
if (hasWritable) {
desc.setWritable(ToBoolean(v));
}
// Steps 11-12.
id = NameToId(cx->names().get);
bool hasGet = false;
if (!GetPropertyIfPresent(cx, obj, id, &v, &hasGet)) {
return false;
}
RootedObject getter(cx);
if (hasGet) {
if (v.isObject()) {
if (checkAccessors) {
JS_TRY_OR_RETURN_FALSE(cx, CheckCallable(cx, &v.toObject(), "getter"));
}
getter = &v.toObject();
} else if (v.isUndefined()) {
getter = nullptr;
} else {
JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr,
JSMSG_BAD_GET_SET_FIELD, "getter");
return false;
}
}
// Steps 13-14.
id = NameToId(cx->names().set);
bool hasSet = false;
if (!GetPropertyIfPresent(cx, obj, id, &v, &hasSet)) {
return false;
}
RootedObject setter(cx);
if (hasSet) {
if (v.isObject()) {
if (checkAccessors) {
JS_TRY_OR_RETURN_FALSE(cx, CheckCallable(cx, &v.toObject(), "setter"));
}
setter = &v.toObject();
} else if (v.isUndefined()) {
setter = nullptr;
} else {
JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr,
JSMSG_BAD_GET_SET_FIELD, "setter");
return false;
}
}
// Step 15.
if (hasGet || hasSet) {
if (hasValue || hasWritable) {
JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr,
JSMSG_INVALID_DESCRIPTOR);
return false;
}
// We delay setGetter/setSetter after the previous check,
// because otherwise we would assert.
if (hasGet) {
desc.setGetter(getter);
}
if (hasSet) {
desc.setSetter(setter);
}
}
desc.assertValid();
desc_.set(desc);
return true;
}
Result<> js::CheckPropertyDescriptorAccessors(JSContext* cx,
Handle<PropertyDescriptor> desc) {
if (desc.hasGetter()) {
MOZ_TRY(CheckCallable(cx, desc.getter(), "getter"));
}
if (desc.hasSetter()) {
MOZ_TRY(CheckCallable(cx, desc.setter(), "setter"));
}
return Ok();
}
// 6.2.5.6 CompletePropertyDescriptor(Desc)
void js::CompletePropertyDescriptor(MutableHandle<PropertyDescriptor> desc) {
// Step 1.
desc.assertValid();
// Step 2.
// Let like be the Record { [[Value]]: undefined, [[Writable]]: false,
// [[Get]]: undefined, [[Set]]: undefined,
// [[Enumerable]]: false, [[Configurable]]: false }.
// Step 3.
if (desc.isGenericDescriptor() || desc.isDataDescriptor()) {
// Step 3.a.
if (!desc.hasValue()) {
desc.setValue(UndefinedHandleValue);
}
// Step 3.b.
if (!desc.hasWritable()) {
desc.setWritable(false);
}
} else {
// Step 4.a.
if (!desc.hasGetter()) {
desc.setGetter(nullptr);
}
// Step 4.b.
if (!desc.hasSetter()) {
desc.setSetter(nullptr);
}
}
// Step 5.
if (!desc.hasEnumerable()) {
desc.setEnumerable(false);
}
// Step 6.
if (!desc.hasConfigurable()) {
desc.setConfigurable(false);
}
desc.assertComplete();
}
bool js::ReadPropertyDescriptors(
JSContext* cx, HandleObject props, bool checkAccessors,
MutableHandleIdVector ids, MutableHandle<PropertyDescriptorVector> descs) {
if (!GetPropertyKeys(cx, props, JSITER_OWNONLY | JSITER_SYMBOLS, ids)) {
return false;
}
RootedId id(cx);
for (size_t i = 0, len = ids.length(); i < len; i++) {
id = ids[i];
Rooted<PropertyDescriptor> desc(cx);
RootedValue v(cx);
if (!GetProperty(cx, props, props, id, &v) ||
!ToPropertyDescriptor(cx, v, checkAccessors, &desc) ||
!descs.append(desc)) {
return false;
}
}
return true;
}
/*** Seal and freeze ********************************************************/
/* ES6 draft rev 29 (6 Dec 2014) 7.3.13. */
bool js::SetIntegrityLevel(JSContext* cx, HandleObject obj,
IntegrityLevel level) {
cx->check(obj);
// Steps 3-5. (Steps 1-2 are redundant assertions.)
if (!PreventExtensions(cx, obj)) {
return false;
}
// Steps 6-9, loosely interpreted.
if (obj->is<NativeObject>() && !obj->is<TypedArrayObject>() &&
!obj->is<MappedArgumentsObject>()) {
Handle<NativeObject*> nobj = obj.as<NativeObject>();
// Use a fast path to seal/freeze properties. This has the benefit of
// creating shared property maps if possible, whereas the slower/generic
// implementation below ends up converting non-empty objects to dictionary
// mode.
if (nobj->shape()->propMapLength() > 0) {
if (!NativeObject::freezeOrSealProperties(cx, nobj, level)) {
return false;
}
}
// Ordinarily ArraySetLength handles this, but we're going behind its back
// right now, so we must do this manually.
if (level == IntegrityLevel::Frozen && obj->is<ArrayObject>()) {
obj->as<ArrayObject>().setNonWritableLength(cx);
}
} else {
// Steps 6-7.
RootedIdVector keys(cx);
if (!GetPropertyKeys(
cx, obj, JSITER_HIDDEN | JSITER_OWNONLY | JSITER_SYMBOLS, &keys)) {
return false;
}
RootedId id(cx);
Rooted<PropertyDescriptor> desc(cx, PropertyDescriptor::Empty());
// 8.a/9.a. The two different loops are merged here.
for (size_t i = 0; i < keys.length(); i++) {
id = keys[i];
if (level == IntegrityLevel::Sealed) {
// 8.a.i.
desc.setConfigurable(false);
} else {
// 9.a.i-ii.
Rooted<Maybe<PropertyDescriptor>> currentDesc(cx);
if (!GetOwnPropertyDescriptor(cx, obj, id, &currentDesc)) {
return false;
}
// 9.a.iii.
if (currentDesc.isNothing()) {
continue;
}
// 9.a.iii.1-2
desc = PropertyDescriptor::Empty();
if (currentDesc->isAccessorDescriptor()) {
desc.setConfigurable(false);
} else {
desc.setConfigurable(false);
desc.setWritable(false);
}
}
// 8.a.i-ii. / 9.a.iii.3-4
if (!DefineProperty(cx, obj, id, desc)) {
return false;
}
}
}
// Finally, freeze or seal the dense elements.
if (obj->is<NativeObject>()) {
if (!ObjectElements::FreezeOrSeal(cx, obj.as<NativeObject>(), level)) {
return false;
}
}
return true;
}
static bool ResolveLazyProperties(JSContext* cx, Handle<NativeObject*> obj) {
const JSClass* clasp = obj->getClass();
if (JSEnumerateOp enumerate = clasp->getEnumerate()) {
if (!enumerate(cx, obj)) {
return false;
}
}
if (clasp->getNewEnumerate() && clasp->getResolve()) {
RootedIdVector properties(cx);
if (!clasp->getNewEnumerate()(cx, obj, &properties,
/* enumerableOnly = */ false)) {
return false;
}
RootedId id(cx);
for (size_t i = 0; i < properties.length(); i++) {
id = properties[i];
bool found;
if (!HasOwnProperty(cx, obj, id, &found)) {
return false;
}
}
}
return true;
}
// ES6 draft rev33 (12 Feb 2015) 7.3.15
bool js::TestIntegrityLevel(JSContext* cx, HandleObject obj,
IntegrityLevel level, bool* result) {
// Steps 3-6. (Steps 1-2 are redundant assertions.)
bool status;
if (!IsExtensible(cx, obj, &status)) {
return false;
}
if (status) {
*result = false;
return true;
}
// Fast path for native objects.
if (obj->is<NativeObject>()) {
Handle<NativeObject*> nobj = obj.as<NativeObject>();
// Force lazy properties to be resolved.
if (!ResolveLazyProperties(cx, nobj)) {
return false;
}
// Typed array elements are configurable, writable properties, so if any
// elements are present, the typed array can neither be sealed nor frozen.
if (nobj->is<TypedArrayObject>() &&
nobj->as<TypedArrayObject>().length().valueOr(0) > 0) {
*result = false;
return true;
}
bool hasDenseElements = false;
for (size_t i = 0; i < nobj->getDenseInitializedLength(); i++) {
if (nobj->containsDenseElement(i)) {
hasDenseElements = true;
break;
}
}
if (hasDenseElements) {
// Unless the sealed flag is set, dense elements are configurable.
if (!nobj->denseElementsAreSealed()) {
*result = false;
return true;
}
// Unless the frozen flag is set, dense elements are writable.
if (level == IntegrityLevel::Frozen && !nobj->denseElementsAreFrozen()) {
*result = false;
return true;
}
}
// Steps 7-9.
for (ShapePropertyIter<NoGC> iter(nobj->shape()); !iter.done(); iter++) {
// Steps 9.c.i-ii.
if (iter->configurable() ||
(level == IntegrityLevel::Frozen && iter->isDataDescriptor() &&
iter->writable())) {
// Private fields on objects don't participate in the frozen state, and
// so should be elided from checking for frozen state.
if (iter->key().isPrivateName()) {
continue;
}
*result = false;
return true;
}
}
} else {
// Steps 7-8.
RootedIdVector props(cx);
if (!GetPropertyKeys(
cx, obj, JSITER_HIDDEN | JSITER_OWNONLY | JSITER_SYMBOLS, &props)) {
return false;
}
// Step 9.
RootedId id(cx);
Rooted<Maybe<PropertyDescriptor>> desc(cx);
for (size_t i = 0, len = props.length(); i < len; i++) {
id = props[i];
// Steps 9.a-b.
if (!GetOwnPropertyDescriptor(cx, obj, id, &desc)) {
return false;
}
// Step 9.c.
if (desc.isNothing()) {
continue;
}
// Steps 9.c.i-ii.
if (desc->configurable() ||
(level == IntegrityLevel::Frozen && desc->isDataDescriptor() &&
desc->writable())) {
// Since we don't request JSITER_PRIVATE in GetPropertyKeys above, we
// should never see a private name here.
MOZ_ASSERT(!id.isPrivateName());
*result = false;
return true;
}
}
}
// Step 10.
*result = true;
return true;
}
/* * */
static MOZ_ALWAYS_INLINE NativeObject* NewObject(
JSContext* cx, const JSClass* clasp, Handle<TaggedProto> proto,
gc::AllocKind kind, NewObjectKind newKind, ObjectFlags objFlags,
gc::AllocSite* allocSite = nullptr) {
MOZ_ASSERT(clasp->isNativeObject());
// Some classes have specialized allocation functions and shouldn't end up
// here.
MOZ_ASSERT(clasp != &ArrayObject::class_);
MOZ_ASSERT(clasp != &PlainObject::class_);
MOZ_ASSERT(!clasp->isJSFunction());
MOZ_ASSERT_IF(allocSite, allocSite->zone() == cx->zone());
// Computing nfixed based on the AllocKind isn't right for objects which can
// store fixed data inline (TypedArrays and ArrayBuffers) so for simplicity
// and performance reasons we don't support such objects here.
MOZ_ASSERT(!ClassCanHaveFixedData(clasp));
size_t nfixed = GetGCKindSlots(kind);
if (CanChangeToBackgroundAllocKind(kind, clasp)) {
kind = ForegroundToBackgroundAllocKind(kind);
}
Rooted<SharedShape*> shape(
cx, SharedShape::getInitialShape(cx, clasp, cx->realm(), proto, nfixed,
objFlags));
if (!shape) {
return nullptr;
}
gc::Heap heap = GetInitialHeap(newKind, clasp, allocSite);
NativeObject* obj = NativeObject::create(cx, kind, heap, shape, allocSite);
if (!obj) {
return nullptr;
}
probes::CreateObject(cx, obj);
return obj;
}
NativeObject* js::NewObjectWithGivenTaggedProto(
JSContext* cx, const JSClass* clasp, Handle<TaggedProto> proto,
gc::AllocKind allocKind, NewObjectKind newKind, ObjectFlags objFlags) {
return NewObject(cx, clasp, proto, allocKind, newKind, objFlags);
}
NativeObject* js::NewObjectWithGivenTaggedProtoAndAllocSite(
JSContext* cx, const JSClass* clasp, Handle<TaggedProto> proto,
gc::AllocKind allocKind, NewObjectKind newKind, ObjectFlags objFlags,
gc::AllocSite* site) {
return NewObject(cx, clasp, proto, allocKind, newKind, objFlags, site);
}
NativeObject* js::NewObjectWithClassProto(JSContext* cx, const JSClass* clasp,
HandleObject protoArg,
gc::AllocKind allocKind,
NewObjectKind newKind,
ObjectFlags objFlags) {
if (protoArg) {
return NewObjectWithGivenTaggedProto(cx, clasp, AsTaggedProto(protoArg),
allocKind, newKind, objFlags);
}
// Find the appropriate proto for clasp. Built-in classes have a cached
// proto on cx->global(); all others get %ObjectPrototype%.
JSProtoKey protoKey = JSCLASS_CACHED_PROTO_KEY(clasp);
if (protoKey == JSProto_Null) {
protoKey = JSProto_Object;
}
JSObject* proto = GlobalObject::getOrCreatePrototype(cx, protoKey);
if (!proto) {
return nullptr;
}
Rooted<TaggedProto> taggedProto(cx, TaggedProto(proto));
return NewObject(cx, clasp, taggedProto, allocKind, newKind, objFlags);
}
bool js::GetPrototypeFromConstructor(JSContext* cx, HandleObject newTarget,
JSProtoKey intrinsicDefaultProto,
MutableHandleObject proto) {
RootedValue protov(cx);
if (!GetProperty(cx, newTarget, newTarget, cx->names().prototype, &protov)) {
return false;
}
if (protov.isObject()) {
proto.set(&protov.toObject());
} else if (newTarget->is<JSFunction>() &&
newTarget->as<JSFunction>().realm() == cx->realm()) {
// Steps 4.a-b fetch the builtin prototype of the current realm, which we
// represent as nullptr.
proto.set(nullptr);
} else if (intrinsicDefaultProto == JSProto_Null) {
// Bug 1317416. The caller did not pass a reasonable JSProtoKey, so let the
// caller select a prototype object. Most likely they will choose one from
// the wrong realm.
proto.set(nullptr);
} else {
// Step 4.a: Let realm be ? GetFunctionRealm(constructor);
Realm* realm = JS::GetFunctionRealm(cx, newTarget);
if (!realm) {
return false;
}
// Step 4.b: Set proto to realm's intrinsic object named
// intrinsicDefaultProto.
{
Maybe<AutoRealm> ar;
if (cx->realm() != realm) {
ar.emplace(cx, realm->maybeGlobal());
}
proto.set(GlobalObject::getOrCreatePrototype(cx, intrinsicDefaultProto));
}
if (!proto) {
return false;
}
if (!cx->compartment()->wrap(cx, proto)) {
return false;
}
}
return true;
}
/* static */
bool JSObject::nonNativeSetProperty(JSContext* cx, HandleObject obj,
HandleId id, HandleValue v,
HandleValue receiver,
ObjectOpResult& result) {
return obj->getOpsSetProperty()(cx, obj, id, v, receiver, result);
}
/* static */
bool JSObject::nonNativeSetElement(JSContext* cx, HandleObject obj,
uint32_t index, HandleValue v,
HandleValue receiver,
ObjectOpResult& result) {
RootedId id(cx);
if (!IndexToId(cx, index, &id)) {
return false;
}
return nonNativeSetProperty(cx, obj, id, v, receiver, result);
}
static bool CopyPropertyFrom(JSContext* cx, HandleId id, HandleObject target,
HandleObject obj) {
// |target| must not be a CCW because we need to enter its realm below and
// CCWs are not associated with a single realm.
MOZ_ASSERT(!IsCrossCompartmentWrapper(target));
// |obj| and |cx| are generally not same-compartment with |target| here.
cx->check(obj, id);
Rooted<mozilla::Maybe<PropertyDescriptor>> desc(cx);
if (!GetOwnPropertyDescriptor(cx, obj, id, &desc)) {
return false;
}
MOZ_ASSERT(desc.isSome());
JSAutoRealm ar(cx, target);
cx->markId(id);
RootedId wrappedId(cx, id);
if (!cx->compartment()->wrap(cx, &desc)) {
return false;
}
Rooted<PropertyDescriptor> desc_(cx, *desc);
return DefineProperty(cx, target, wrappedId, desc_);
}
JS_PUBLIC_API bool JS_CopyOwnPropertiesAndPrivateFields(JSContext* cx,
HandleObject target,
HandleObject obj) {
// Both |obj| and |target| must not be CCWs because we need to enter their
// realms below and CCWs are not associated with a single realm.
MOZ_ASSERT(!IsCrossCompartmentWrapper(obj));
MOZ_ASSERT(!IsCrossCompartmentWrapper(target));
JSAutoRealm ar(cx, obj);
RootedIdVector props(cx);
if (!GetPropertyKeys(
cx, obj,
JSITER_PRIVATE | JSITER_OWNONLY | JSITER_HIDDEN | JSITER_SYMBOLS,
&props)) {
return false;
}
for (size_t i = 0; i < props.length(); ++i) {
if (!CopyPropertyFrom(cx, props[i], target, obj)) {
return false;
}
}
return true;
}
static bool InitializePropertiesFromCompatibleNativeObject(
JSContext* cx, Handle<NativeObject*> dst, Handle<NativeObject*> src) {
cx->check(src, dst);
MOZ_ASSERT(src->getClass() == dst->getClass());
MOZ_ASSERT(dst->shape()->objectFlags().isEmpty());
MOZ_ASSERT(src->numFixedSlots() == dst->numFixedSlots());
MOZ_ASSERT(!src->inDictionaryMode());
MOZ_ASSERT(!dst->inDictionaryMode());
if (!dst->ensureElements(cx, src->getDenseInitializedLength())) {
return false;
}
uint32_t initialized = src->getDenseInitializedLength();
for (uint32_t i = 0; i < initialized; ++i) {
dst->setDenseInitializedLength(i + 1);
dst->initDenseElement(i, src->getDenseElement(i));
}
// If there are no properties to copy, we're done.
if (!src->sharedShape()->propMap()) {
return true;
}
Rooted<SharedShape*> shape(cx);
if (src->staticPrototype() == dst->staticPrototype()) {
shape = src->sharedShape();
} else {
// We need to generate a new shape for dst that has dst's proto but all
// the property information from src. Note that we asserted above that
// dst's object flags are empty.
SharedShape* srcShape = src->sharedShape();
ObjectFlags objFlags;
objFlags = CopyPropMapObjectFlags(objFlags, srcShape->objectFlags());
Rooted<SharedPropMap*> map(cx, srcShape->propMap());
uint32_t mapLength = srcShape->propMapLength();
shape = SharedShape::getPropMapShape(cx, dst->shape()->base(),
dst->numFixedSlots(), map, mapLength,
objFlags);
if (!shape) {
return false;
}
}
uint32_t oldSpan = dst->sharedShape()->slotSpan();
uint32_t newSpan = shape->slotSpan();
if (!dst->setShapeAndAddNewSlots(cx, shape, oldSpan, newSpan)) {
return false;
}
for (size_t i = JSCLASS_RESERVED_SLOTS(src->getClass()); i < newSpan; i++) {
dst->setSlot(i, src->getSlot(i));
}
return true;
}
JS_PUBLIC_API bool JS_InitializePropertiesFromCompatibleNativeObject(
JSContext* cx, HandleObject dst, HandleObject src) {
return InitializePropertiesFromCompatibleNativeObject(
cx, dst.as<NativeObject>(), src.as<NativeObject>());
}
bool js::ObjectMayBeSwapped(const JSObject* obj) {
const JSClass* clasp = obj->getClass();
// We want to optimize Window/globals and Gecko doesn't require transplanting
// them (only the WindowProxy around them). A Window may be a DOMClass, so we
// explicitly check if this is a global.
if (clasp->isGlobal()) {
return false;
}
// WindowProxy, Wrapper, DeadProxyObject, DOMProxy, and DOMClass (non-global)
// types may be swapped. It is hard to detect DOMProxy from shell, so target
// proxies in general.
return clasp->isProxyObject() || clasp->isDOMClass();
}
bool NativeObject::prepareForSwap(JSContext* cx,
MutableHandleValueVector slotValuesOut) {
MOZ_ASSERT(slotValuesOut.empty());
for (size_t i = 0; i < slotSpan(); i++) {
if (!slotValuesOut.append(getSlot(i))) {
return false;
}
}
if (hasDynamicSlots()) {
ObjectSlots* slotsHeader = getSlotsHeader();
size_t size = ObjectSlots::allocSize(slotsHeader->capacity());
RemoveCellMemory(this, size, MemoryUse::ObjectSlots);
if (!cx->nursery().isInside(slotsHeader)) {
if (!isTenured()) {
cx->nursery().removeMallocedBuffer(slotsHeader, size);
}
js_free(slotsHeader);
}
setEmptyDynamicSlots(0);
}
if (hasDynamicElements()) {
ObjectElements* elements = getElementsHeader();
void* allocatedElements = getUnshiftedElementsHeader();
size_t count = elements->numAllocatedElements();
size_t size = count * sizeof(HeapSlot);
if (isTenured()) {
RemoveCellMemory(this, size, MemoryUse::ObjectElements);
} else if (cx->nursery().isInside(allocatedElements)) {
// Move nursery allocated elements in case they end up in a tenured
// object.
ObjectElements* newElements =
reinterpret_cast<ObjectElements*>(js_pod_malloc<HeapSlot>(count));
if (!newElements) {
return false;
}
memmove(newElements, elements, size);
elements_ = newElements->elements();
} else {
cx->nursery().removeMallocedBuffer(allocatedElements, size);
}
MOZ_ASSERT(hasDynamicElements());
}
return true;
}
/* static */
bool NativeObject::fixupAfterSwap(JSContext* cx, Handle<NativeObject*> obj,
gc::AllocKind kind,
HandleValueVector slotValues) {
// This object has just been swapped with some other object, and its shape
// no longer reflects its allocated size. Correct this information and
// fill the slots in with the specified values.
MOZ_ASSERT_IF(!obj->inDictionaryMode(),
obj->slotSpan() == slotValues.length());
// Make sure the shape's numFixedSlots() is correct.
size_t nfixed = gc::GetGCKindSlots(kind);
if (nfixed != obj->shape()->numFixedSlots()) {
if (!NativeObject::changeNumFixedSlotsAfterSwap(cx, obj, nfixed)) {
return false;
}
MOZ_ASSERT(obj->shape()->numFixedSlots() == nfixed);
}
uint32_t oldDictionarySlotSpan =
obj->inDictionaryMode() ? slotValues.length() : 0;
MOZ_ASSERT(!obj->hasUniqueId());
size_t ndynamic =
calculateDynamicSlots(nfixed, slotValues.length(), obj->getClass());
size_t currentSlots = obj->getSlotsHeader()->capacity();
MOZ_ASSERT(ndynamic >= currentSlots);
if (ndynamic > currentSlots) {
if (!obj->growSlots(cx, currentSlots, ndynamic)) {
return false;
}
}
if (obj->inDictionaryMode()) {
obj->setDictionaryModeSlotSpan(oldDictionarySlotSpan);
}
for (size_t i = 0, len = slotValues.length(); i < len; i++) {
obj->initSlotUnchecked(i, slotValues[i]);
}
if (obj->hasDynamicElements()) {
ObjectElements* elements = obj->getElementsHeader();
void* allocatedElements = obj->getUnshiftedElementsHeader();
MOZ_ASSERT(!cx->nursery().isInside(allocatedElements));
size_t size = elements->numAllocatedElements() * sizeof(HeapSlot);
if (obj->isTenured()) {
AddCellMemory(obj, size, MemoryUse::ObjectElements);
} else if (!cx->nursery().registerMallocedBuffer(allocatedElements, size)) {
return false;
}
}
return true;
}
[[nodiscard]] bool ProxyObject::prepareForSwap(
JSContext* cx, MutableHandleValueVector valuesOut) {
MOZ_ASSERT(valuesOut.empty());
// Remove the GCPtr<Value>s we're about to swap from the store buffer, to
// ensure we don't trace bogus values.
gc::StoreBuffer& sb = cx->runtime()->gc.storeBuffer();
// Reserve space for the expando, private slot and the reserved slots.
if (!valuesOut.reserve(2 + numReservedSlots())) {
return false;
}
js::detail::ProxyValueArray* valArray = data.values();
sb.unputValue(&valArray->expandoSlot);
sb.unputValue(&valArray->privateSlot);
valuesOut.infallibleAppend(valArray->expandoSlot);
valuesOut.infallibleAppend(valArray->privateSlot);
for (size_t i = 0; i < numReservedSlots(); i++) {
sb.unputValue(&valArray->reservedSlots.slots[i]);
valuesOut.infallibleAppend(valArray->reservedSlots.slots[i]);
}
if (isTenured() && !usingInlineValueArray()) {
size_t count = detail::ProxyValueArray::allocCount(numReservedSlots());
RemoveCellMemory(this, count * sizeof(Value),
MemoryUse::ProxyExternalValueArray);
js_free(valArray);
data.reservedSlots = nullptr;
}
return true;
}
bool ProxyObject::fixupAfterSwap(JSContext* cx,
const HandleValueVector values) {
MOZ_ASSERT(getClass()->isProxyObject());
size_t nreserved = numReservedSlots();
// |values| contains the expando slot, private slot and the reserved slots.
MOZ_ASSERT(values.length() == 2 + nreserved);
// Allocate the external value array in malloc memory, even for nursery
// proxies.
size_t count = detail::ProxyValueArray::allocCount(nreserved);
auto* allocation = js_pod_malloc<JS::Value>(count);
if (!allocation) {
return false;
}
size_t size = count * sizeof(Value);
if (isTenured()) {
AddCellMemory(&asTenured(), size, MemoryUse::ProxyExternalValueArray);
} else if (!cx->nursery().registerMallocedBuffer(allocation, size)) {
js_free(allocation);
return false;
}
auto* valArray = reinterpret_cast<js::detail::ProxyValueArray*>(allocation);
valArray->expandoSlot = values[0];
valArray->privateSlot = values[1];
for (size_t i = 0; i < nreserved; i++) {
valArray->reservedSlots.slots[i] = values[i + 2];
}
data.reservedSlots = &valArray->reservedSlots;
MOZ_ASSERT(!usingInlineValueArray());
return true;
}
static gc::AllocKind SwappableObjectAllocKind(JSObject* obj) {
MOZ_ASSERT(ObjectMayBeSwapped(obj));
if (obj->isTenured()) {
return obj->asTenured().getAllocKind();
}
if (obj->is<NativeObject>()) {
return obj->as<NativeObject>().allocKindForTenure();
}
return obj->as<ProxyObject>().allocKindForTenure();
}
/* Use this method with extreme caution. It trades the guts of two objects. */
void JSObject::swap(JSContext* cx, HandleObject a, HandleObject b,
AutoEnterOOMUnsafeRegion& oomUnsafe) {
// Ensure swap doesn't cause a finalizer to be run at the wrong time.
MOZ_ASSERT(a->isBackgroundFinalized() == b->isBackgroundFinalized());
MOZ_ASSERT(a->compartment() == b->compartment());
// You must have entered the objects' compartment before calling this.
MOZ_ASSERT(cx->compartment() == a->compartment());
// Only certain types of objects are allowed to be swapped. This allows the
// JITs to better optimize objects that can never swap and rules out most
// builtin objects that have special behaviour.
MOZ_RELEASE_ASSERT(js::ObjectMayBeSwapped(a));
MOZ_RELEASE_ASSERT(js::ObjectMayBeSwapped(b));
// Don't allow a GC which may observe intermediate state or run before we
// execute all necessary barriers.
gc::AutoSuppressGC nogc(cx);
if (!Watchtower::watchObjectSwap(cx, a, b)) {
oomUnsafe.crash("watchObjectSwap");
}
// Ensure we update any embedded nursery pointers in either object.
gc::StoreBuffer& storeBuffer = cx->runtime()->gc.storeBuffer();
if (a->isTenured()) {
storeBuffer.putWholeCell(a);
}
if (b->isTenured()) {
storeBuffer.putWholeCell(b);
}
if (a->isTenured() || b->isTenured()) {
if (a->zone()->wasGCStarted()) {
storeBuffer.setMayHavePointersToDeadCells();
}
}
unsigned r = NotifyGCPreSwap(a, b);
ProxyObject* pa = a->is<ProxyObject>() ? &a->as<ProxyObject>() : nullptr;
ProxyObject* pb = b->is<ProxyObject>() ? &b->as<ProxyObject>() : nullptr;
bool aIsProxyWithInlineValues = pa && pa->usingInlineValueArray();
bool bIsProxyWithInlineValues = pb && pb->usingInlineValueArray();
bool aIsUsedAsPrototype = a->isUsedAsPrototype();
bool bIsUsedAsPrototype = b->isUsedAsPrototype();
// Swap element associations.
Zone* zone = a->zone();
// Record any associated unique IDs and prepare for swap.
//
// Note that unique IDs are NOT swapped but remain associated with the
// original address.
uint64_t aid = 0;
uint64_t bid = 0;
(void)gc::MaybeGetUniqueId(a, &aid);
(void)gc::MaybeGetUniqueId(b, &bid);
NativeObject* na = a->is<NativeObject>() ? &a->as<NativeObject>() : nullptr;
NativeObject* nb = b->is<NativeObject>() ? &b->as<NativeObject>() : nullptr;
if ((aid || bid) && (na || nb)) {
// We can't remove unique IDs from native objects when they are swapped with
// objects without an ID. Instead ensure they both have IDs so we always
// have something to overwrite the old ID with.
if (!gc::GetOrCreateUniqueId(a, &aid) ||
!gc::GetOrCreateUniqueId(b, &bid)) {
oomUnsafe.crash("Failed to create unique ID during swap");
}
// IDs stored in NativeObjects could shadow those stored in the zone
// table. Remove any zone table IDs first.
if (pa && aid) {
gc::RemoveUniqueId(a);
}
if (pb && bid) {
gc::RemoveUniqueId(b);
}
}
gc::AllocKind ka = SwappableObjectAllocKind(a);
gc::AllocKind kb = SwappableObjectAllocKind(b);
size_t sa = gc::Arena::thingSize(ka);
size_t sb = gc::Arena::thingSize(kb);
if (sa == sb && a->isTenured() == b->isTenured()) {
// When both objects are the same size and in the same heap, just do a plain
// swap of their contents.
// Swap slot associations.
zone->swapCellMemory(a, b, MemoryUse::ObjectSlots);
size_t size = sa;
char tmp[sizeof(JSObject_Slots16)];
MOZ_ASSERT(size <= sizeof(tmp));
js_memcpy(tmp, a, size);
js_memcpy(a, b, size);
js_memcpy(b, tmp, size);
zone->swapCellMemory(a, b, MemoryUse::ObjectElements);
zone->swapCellMemory(a, b, MemoryUse::ProxyExternalValueArray);
if (aIsProxyWithInlineValues) {
b->as<ProxyObject>().setInlineValueArray();
}
if (bIsProxyWithInlineValues) {
a->as<ProxyObject>().setInlineValueArray();
}
} else {
// When the objects have different sizes, they will have different numbers
// of fixed slots before and after the swap, so the slots for native objects
// will need to be rearranged. Remember the original values from the
// objects.
RootedValueVector avals(cx);
RootedValueVector bvals(cx);
if (na && !na->prepareForSwap(cx, &avals)) {
oomUnsafe.crash("NativeObject::prepareForSwap");
}
if (nb && !nb->prepareForSwap(cx, &bvals)) {
oomUnsafe.crash("NativeObject::prepareForSwap");
}
// Do the same for proxy value arrays.
if (pa && !pa->prepareForSwap(cx, &avals)) {
oomUnsafe.crash("ProxyObject::prepareForSwap");
}
if (pb && !pb->prepareForSwap(cx, &bvals)) {
oomUnsafe.crash("ProxyObject::prepareForSwap");
}
// Swap the main fields of the objects, whether they are native objects or
// proxies.
char tmp[sizeof(JSObject_Slots0)];
js_memcpy(&tmp, a, sizeof tmp);
js_memcpy(a, b, sizeof tmp);
js_memcpy(b, &tmp, sizeof tmp);
if (na &&
!NativeObject::fixupAfterSwap(cx, b.as<NativeObject>(), kb, avals)) {
oomUnsafe.crash("NativeObject::fixupAfterSwap");
}
if (nb &&
!NativeObject::fixupAfterSwap(cx, a.as<NativeObject>(), ka, bvals)) {
oomUnsafe.crash("NativeObject::fixupAfterSwap");
}
if (pa && !b->as<ProxyObject>().fixupAfterSwap(cx, avals)) {
oomUnsafe.crash("ProxyObject::fixupAfterSwap");
}
if (pb && !a->as<ProxyObject>().fixupAfterSwap(cx, bvals)) {
oomUnsafe.crash("ProxyObject::fixupAfterSwap");
}
}
// Restore original unique IDs.
if ((aid || bid) && (na || nb)) {
if ((aid && !gc::SetOrUpdateUniqueId(cx, a, aid)) ||
(bid && !gc::SetOrUpdateUniqueId(cx, b, bid))) {
oomUnsafe.crash("Failed to set unique ID after swap");
}
}
MOZ_ASSERT_IF(aid, gc::GetUniqueIdInfallible(a) == aid);
MOZ_ASSERT_IF(bid, gc::GetUniqueIdInfallible(b) == bid);
// Preserve the IsUsedAsPrototype flag on the objects.
if (aIsUsedAsPrototype) {
if (!JSObject::setIsUsedAsPrototype(cx, a)) {
oomUnsafe.crash("setIsUsedAsPrototype");
}
}
if (bIsUsedAsPrototype) {
if (!JSObject::setIsUsedAsPrototype(cx, b)) {
oomUnsafe.crash("setIsUsedAsPrototype");
}
}
/*
* We need a write barrier here. If |a| was marked and |b| was not, then
* after the swap, |b|'s guts would never be marked. The write barrier
* solves this.
*
* Normally write barriers happen before the write. However, that's not
* necessary here because nothing is being destroyed. We're just swapping.
*/
PreWriteBarrier(zone, a.get(), [](JSTracer* trc, JSObject* obj) {
obj->traceChildren(trc);
});
PreWriteBarrier(zone, b.get(), [](JSTracer* trc, JSObject* obj) {
obj->traceChildren(trc);
});
NotifyGCPostSwap(a, b, r);
}
static NativeObject* DefineConstructorAndPrototype(
JSContext* cx, HandleObject obj, Handle<JSAtom*> atom,
HandleObject protoProto, const JSClass* clasp, Native constructor,
unsigned nargs, const JSPropertySpec* ps, const JSFunctionSpec* fs,
const JSPropertySpec* static_ps, const JSFunctionSpec* static_fs,
NativeObject** ctorp) {
// Create the prototype object.
Rooted<NativeObject*> proto(
cx, GlobalObject::createBlankPrototypeInheriting(cx, clasp, protoProto));
if (!proto) {
return nullptr;
}
Rooted<NativeObject*> ctor(cx);
if (!constructor) {
ctor = proto;
} else {
ctor = NewNativeConstructor(cx, constructor, nargs, atom);
if (!ctor) {
return nullptr;
}
if (!LinkConstructorAndPrototype(cx, ctor, proto)) {
return nullptr;
}
}
if (!DefinePropertiesAndFunctions(cx, proto, ps, fs) ||
(ctor != proto &&
!DefinePropertiesAndFunctions(cx, ctor, static_ps, static_fs))) {
return nullptr;
}
if (clasp->specShouldDefineConstructor()) {
RootedId id(cx, AtomToId(atom));
RootedValue value(cx, ObjectValue(*ctor));
if (!DefineDataProperty(cx, obj, id, value, 0)) {
return nullptr;
}
}
if (ctorp) {
*ctorp = ctor;
}
return proto;
}
NativeObject* js::InitClass(JSContext* cx, HandleObject obj,
const JSClass* protoClass, HandleObject protoProto_,
const char* name, Native constructor,
unsigned nargs, const JSPropertySpec* ps,
const JSFunctionSpec* fs,
const JSPropertySpec* static_ps,
const JSFunctionSpec* static_fs,
NativeObject** ctorp) {
Rooted<JSAtom*> atom(cx, Atomize(cx, name, strlen(name)));
if (!atom) {
return nullptr;
}
/*
* All instances of the class will inherit properties from the prototype
* object we are about to create (in DefineConstructorAndPrototype), which
* in turn will inherit from protoProto.
*
* If protoProto is nullptr, default to Object.prototype.
* If protoClass is nullptr, default to PlainObject.
*/
RootedObject protoProto(cx, protoProto_);
if (!protoProto) {
protoProto = &cx->global()->getObjectPrototype();
}
if (!protoClass) {
protoClass = &PlainObject::class_;
}
return DefineConstructorAndPrototype(cx, obj, atom, protoProto, protoClass,
constructor, nargs, ps, fs, static_ps,
static_fs, ctorp);
}
/**
* Returns the original Object.prototype from the embedding-provided incumbent
* global.
*
* Really, we want the incumbent global itself so we can pass it to other
* embedding hooks which need it. Specifically, the enqueue promise hook
* takes an incumbent global so it can set that on the PromiseCallbackJob
* it creates.
*
* The reason for not just returning the global itself is that we'd need to
* wrap it into the current compartment, and later unwrap it. Unwrapping
* globals is tricky, though: we might accidentally unwrap through an inner
* to its outer window and end up with the wrong global. Plain objects don't
* have this problem, so we use the global's Object.prototype. The code using
* it - e.g. EnqueuePromiseReactionJob - can then unwrap the object and get
* its global without fear of unwrapping too far.
*/
bool js::GetObjectFromHostDefinedData(JSContext* cx, MutableHandleObject obj) {
if (!cx->runtime()->getHostDefinedData(cx, obj)) {
return false;
}
// The object might be from a different compartment, so wrap it.
if (obj && !cx->compartment()->wrap(cx, obj)) {
return false;
}
return true;
}
static bool IsStandardPrototype(JSObject* obj, JSProtoKey key) {
return obj->nonCCWGlobal().maybeGetPrototype(key) == obj;
}
JSProtoKey JS::IdentifyStandardInstance(JSObject* obj) {
// Note: The prototype shares its JSClass with instances.
MOZ_ASSERT(!obj->is<CrossCompartmentWrapperObject>());
JSProtoKey key = StandardProtoKeyOrNull(obj);
if (key != JSProto_Null && !IsStandardPrototype(obj, key)) {
return key;
}
return JSProto_Null;
}
JSProtoKey JS::IdentifyStandardPrototype(JSObject* obj) {
// Note: The prototype shares its JSClass with instances.
MOZ_ASSERT(!obj->is<CrossCompartmentWrapperObject>());
JSProtoKey key = StandardProtoKeyOrNull(obj);
if (key != JSProto_Null && IsStandardPrototype(obj, key)) {
return key;
}
return JSProto_Null;
}
JSProtoKey JS::IdentifyStandardInstanceOrPrototype(JSObject* obj) {
return StandardProtoKeyOrNull(obj);
}
JSProtoKey JS::IdentifyStandardConstructor(JSObject* obj) {
// Note that isNativeConstructor does not imply that we are a standard
// constructor, but the converse is true (at least until we start having
// self-hosted constructors for standard classes). This lets us avoid a costly
// loop for many functions (which, depending on the call site, may be the
// common case).
if (!obj->is<JSFunction>() ||
!(obj->as<JSFunction>().flags().isNativeConstructor())) {
return JSProto_Null;
}
static_assert(JSProto_Null == 0,
"Loop below can start at 1 to skip JSProto_Null");
GlobalObject& global = obj->as<JSFunction>().global();
for (size_t k = 1; k < JSProto_LIMIT; ++k) {
JSProtoKey key = static_cast<JSProtoKey>(k);
if (global.maybeGetConstructor(key) == obj) {
return key;
}
}
return JSProto_Null;
}
bool js::LookupProperty(JSContext* cx, HandleObject obj, js::HandleId id,
MutableHandleObject objp, PropertyResult* propp) {
if (LookupPropertyOp op = obj->getOpsLookupProperty()) {
return op(cx, obj, id, objp, propp);
}
return NativeLookupPropertyInline<CanGC>(cx, obj.as<NativeObject>(), id, objp,
propp);
}
bool js::LookupName(JSContext* cx, Handle<PropertyName*> name,
HandleObject envChain, MutableHandleObject objp,
MutableHandleObject pobjp, PropertyResult* propp) {
RootedId id(cx, NameToId(name));
for (RootedObject env(cx, envChain); env; env = env->enclosingEnvironment()) {
if (!LookupProperty(cx, env, id, pobjp, propp)) {
return false;
}
if (propp->isFound()) {
objp.set(env);
return true;
}
}
objp.set(nullptr);
pobjp.set(nullptr);
propp->setNotFound();
return true;
}
bool js::LookupNameNoGC(JSContext* cx, PropertyName* name, JSObject* envChain,
NativeObject** pobjp, PropertyResult* propp) {
AutoAssertNoPendingException nogc(cx);
MOZ_ASSERT(!*pobjp && propp->isNotFound());
for (JSObject* env = envChain; env; env = env->enclosingEnvironment()) {
if (env->getOpsLookupProperty()) {
return false;
}
if (!NativeLookupPropertyInline<NoGC>(cx, &env->as<NativeObject>(),
NameToId(name), pobjp, propp)) {
return false;
}
if (propp->isFound()) {
return true;
}
}
return true;
}
static bool IsTemporalDeadZone(JSContext* cx, HandleObject env, HandleId id,
const PropertyResult& prop, bool* isTDZ) {
MOZ_ASSERT(prop.isFound());
// We do our own explicit checking for |this|
if (id.isAtom(cx->names().dot_this_)) {
*isTDZ = false;
return true;
}
// Treat Debugger environments specially for TDZ checks, as they
// look like non-native environments but in fact wrap native
// environments.
if (env->is<DebugEnvironmentProxy>()) {
RootedValue v(cx);
auto envProxy = env.as<DebugEnvironmentProxy>();
if (!DebugEnvironmentProxy::getMaybeSentinelValue(cx, envProxy, id, &v)) {
return false;
}
*isTDZ = IsUninitializedLexical(v);
return true;
}
*isTDZ = IsUninitializedLexicalSlot(env, prop);
return true;
}
JSObject* js::LookupNameWithGlobalDefault(JSContext* cx,
Handle<PropertyName*> name,
HandleObject envChain) {
RootedId id(cx, NameToId(name));
RootedObject pobj(cx);
PropertyResult prop;
RootedObject env(cx, envChain);
for (; !env->is<GlobalObject>(); env = env->enclosingEnvironment()) {
if (!LookupProperty(cx, env, id, &pobj, &prop)) {
return nullptr;
}
if (prop.isFound()) {
break;
}
}
// Uninitialized lexicals can't appear on the prototype chain, so only check
// for TDZ when |pobj == env|.
//
// JSOp::BindName is always directly followed by JSOp::GetBoundName, so don't
// bother to create a RuntimeLexicalErrorObject.
if (pobj == env) {
MOZ_ASSERT(prop.isFound());
bool isTDZ;
if (!IsTemporalDeadZone(cx, env, id, prop, &isTDZ)) {
return nullptr;
}
if (isTDZ) {
ReportRuntimeLexicalError(cx, JSMSG_UNINITIALIZED_LEXICAL, name);
return nullptr;
}
}
return env;
}
JSObject* js::LookupNameUnqualified(JSContext* cx, Handle<PropertyName*> name,
HandleObject envChain) {
RootedId id(cx, NameToId(name));
RootedObject pobj(cx);
PropertyResult prop;
RootedObject env(cx, envChain);
for (; !env->isUnqualifiedVarObj(); env = env->enclosingEnvironment()) {
if (!LookupProperty(cx, env, id, &pobj, &prop)) {
return nullptr;
}
if (prop.isFound()) {
break;
}
}
// Uninitialized lexicals can't appear on the prototype chain, so only check
// for TDZ and `const` bindings when |pobj == env|.
//
// See note above RuntimeLexicalErrorObject.
if (pobj == env) {
MOZ_ASSERT(prop.isFound());
bool isTDZ;
if (!IsTemporalDeadZone(cx, env, id, prop, &isTDZ)) {
return nullptr;
}
if (isTDZ) {
return RuntimeLexicalErrorObject::create(cx, env,
JSMSG_UNINITIALIZED_LEXICAL);
}
if (env->is<LexicalEnvironmentObject>() &&
!prop.propertyInfo().writable()) {
// Assigning to a named lambda callee name is a no-op in sloppy mode.
if (!(env->is<BlockLexicalEnvironmentObject>() &&
env->as<BlockLexicalEnvironmentObject>().scope().kind() ==
ScopeKind::NamedLambda)) {
MOZ_ASSERT(name != cx->names().dot_this_);
return RuntimeLexicalErrorObject::create(cx, env,
JSMSG_BAD_CONST_ASSIGN);
}
}
}
return env;
}
bool js::HasOwnProperty(JSContext* cx, HandleObject obj, HandleId id,
bool* result) {
if (obj->is<ProxyObject>()) {
return Proxy::hasOwn(cx, obj, id, result);
}
if (GetOwnPropertyOp op = obj->getOpsGetOwnPropertyDescriptor()) {
Rooted<mozilla::Maybe<PropertyDescriptor>> desc(cx);
if (!op(cx, obj, id, &desc)) {
return false;
}
*result = desc.isSome();
return true;
}
PropertyResult prop;
if (!NativeLookupOwnProperty<CanGC>(cx, obj.as<NativeObject>(), id, &prop)) {
return false;
}
*result = prop.isFound();
return true;
}
bool js::LookupPropertyPure(JSContext* cx, JSObject* obj, jsid id,
NativeObject** objp, PropertyResult* propp) {
if (obj->getOpsLookupProperty()) {
return false;
}
return NativeLookupPropertyInline<NoGC, LookupResolveMode::CheckMayResolve>(
cx, &obj->as<NativeObject>(), id, objp, propp);
}
bool js::LookupOwnPropertyPure(JSContext* cx, JSObject* obj, jsid id,
PropertyResult* propp) {
if (obj->getOpsLookupProperty()) {
return false;
}
return NativeLookupOwnPropertyInline<NoGC,
LookupResolveMode::CheckMayResolve>(
cx, &obj->as<NativeObject>(), id, propp);
}
static inline bool NativeGetPureInline(NativeObject* pobj, jsid id,
PropertyResult prop, Value* vp,
JSContext* cx) {
if (prop.isDenseElement()) {
*vp = pobj->getDenseElement(prop.denseElementIndex());
return true;
}
if (prop.isTypedArrayElement()) {
size_t idx = prop.typedArrayElementIndex();
return pobj->as<TypedArrayObject>().getElement<NoGC>(cx, idx, vp);
}
// Fail if we have a custom getter.
PropertyInfo propInfo = prop.propertyInfo();
if (!propInfo.isDataProperty()) {
return false;
}
*vp = pobj->getSlot(propInfo.slot());
MOZ_ASSERT(!vp->isMagic());
return true;
}
bool js::GetPropertyPure(JSContext* cx, JSObject* obj, jsid id, Value* vp) {
NativeObject* pobj;
PropertyResult prop;
if (!LookupPropertyPure(cx, obj, id, &pobj, &prop)) {
return false;
}
if (prop.isNotFound()) {
vp->setUndefined();
return true;
}
return NativeGetPureInline(pobj, id, prop, vp, cx);
}
bool js::GetOwnPropertyPure(JSContext* cx, JSObject* obj, jsid id, Value* vp,
bool* found) {
PropertyResult prop;
if (!LookupOwnPropertyPure(cx, obj, id, &prop)) {
return false;
}
if (prop.isNotFound()) {
*found = false;
vp->setUndefined();
return true;
}
*found = true;
return obj->is<NativeObject>() &&
NativeGetPureInline(&obj->as<NativeObject>(), id, prop, vp, cx);
}
static inline bool NativeGetGetterPureInline(NativeObject* holder,
PropertyResult prop,
JSFunction** fp) {
MOZ_ASSERT(prop.isNativeProperty());
PropertyInfo propInfo = prop.propertyInfo();
if (holder->hasGetter(propInfo)) {
JSObject* getter = holder->getGetter(propInfo);
if (getter->is<JSFunction>()) {
*fp = &getter->as<JSFunction>();
return true;
}
}
*fp = nullptr;
return true;
}
bool js::GetGetterPure(JSContext* cx, JSObject* obj, jsid id, JSFunction** fp) {
/* Just like GetPropertyPure, but get getter function, without invoking
* it. */
NativeObject* pobj;
PropertyResult prop;
if (!LookupPropertyPure(cx, obj, id, &pobj, &prop)) {
return false;
}
if (prop.isNotFound()) {
*fp = nullptr;
return true;
}
return prop.isNativeProperty() && NativeGetGetterPureInline(pobj, prop, fp);
}
bool js::GetOwnGetterPure(JSContext* cx, JSObject* obj, jsid id,
JSFunction** fp) {
JS::AutoCheckCannotGC nogc;
PropertyResult prop;
if (!LookupOwnPropertyPure(cx, obj, id, &prop)) {
return false;
}
if (prop.isNotFound()) {
*fp = nullptr;
return true;
}
return prop.isNativeProperty() &&
NativeGetGetterPureInline(&obj->as<NativeObject>(), prop, fp);
}
bool js::GetOwnNativeGetterPure(JSContext* cx, JSObject* obj, jsid id,
JSNative* native) {
JS::AutoCheckCannotGC nogc;
*native = nullptr;
PropertyResult prop;
if (!LookupOwnPropertyPure(cx, obj, id, &prop)) {
return false;
}
if (!prop.isNativeProperty()) {
return true;
}
PropertyInfo propInfo = prop.propertyInfo();
NativeObject* nobj = &obj->as<NativeObject>();
if (!nobj->hasGetter(propInfo)) {
return true;
}
JSObject* getterObj = nobj->getGetter(propInfo);
if (!getterObj->is<JSFunction>()) {
return true;
}
JSFunction* getter = &getterObj->as<JSFunction>();
if (!getter->isNativeFun()) {
return true;
}
*native = getter->native();
return true;
}
bool js::HasOwnDataPropertyPure(JSContext* cx, JSObject* obj, jsid id,
bool* result) {
PropertyResult prop;
if (!LookupOwnPropertyPure(cx, obj, id, &prop)) {
return false;
}
*result = prop.isNativeProperty() && prop.propertyInfo().isDataProperty();
return true;
}
bool js::GetPrototypeIfOrdinary(JSContext* cx, HandleObject obj,
bool* isOrdinary, MutableHandleObject protop) {
if (obj->is<js::ProxyObject>()) {
return js::Proxy::getPrototypeIfOrdinary(cx, obj, isOrdinary, protop);
}
*isOrdinary = true;
protop.set(obj->staticPrototype());
return true;
}
/*** ES6 standard internal methods ******************************************/
bool js::SetPrototype(JSContext* cx, HandleObject obj, HandleObject proto,
JS::ObjectOpResult& result) {
// The proxy trap subsystem fully handles prototype-setting for proxies
// with dynamic [[Prototype]]s.
if (obj->hasDynamicPrototype()) {
MOZ_ASSERT(obj->is<ProxyObject>());
return Proxy::setPrototype(cx, obj, proto, result);
}
/*
* ES6 9.1.2 step 3-4 if |obj.[[Prototype]]| has SameValue as |proto| return
* true. Since the values in question are objects, we can just compare
* pointers.
*/
if (proto == obj->staticPrototype()) {
return result.succeed();
}
/* Disallow mutation of immutable [[Prototype]]s. */
if (obj->staticPrototypeIsImmutable()) {
return result.fail(JSMSG_CANT_SET_PROTO);
}
/*
* Disallow mutating the [[Prototype]] on WebAssembly GC objects.
*/
if (obj->is<WasmGcObject>()) {
return result.fail(JSMSG_CANT_SET_PROTO);
}
/* ES6 9.1.2 step 5 forbids changing [[Prototype]] if not [[Extensible]]. */
bool extensible;
if (!IsExtensible(cx, obj, &extensible)) {
return false;
}
if (!extensible) {
return result.fail(JSMSG_CANT_SET_PROTO);
}
/*
* ES6 9.1.2 step 6 forbids generating cyclical prototype chains. But we
* have to do this comparison on the observable WindowProxy, not on the
* possibly-Window object we're setting the proto on.
*/
RootedObject objMaybeWindowProxy(cx, ToWindowProxyIfWindow(obj));
RootedObject obj2(cx, proto);
while (obj2) {
MOZ_ASSERT(!IsWindow(obj2));
if (obj2 == objMaybeWindowProxy) {
return result.fail(JSMSG_CANT_SET_PROTO_CYCLE);
}
bool isOrdinary;
if (!GetPrototypeIfOrdinary(cx, obj2, &isOrdinary, &obj2)) {
return false;
}
if (!isOrdinary) {
break;
}
}
Rooted<TaggedProto> taggedProto(cx, TaggedProto(proto));
if (!JSObject::setProtoUnchecked(cx, obj, taggedProto)) {
return false;
}
return result.succeed();
}
bool js::SetPrototype(JSContext* cx, HandleObject obj, HandleObject proto) {
ObjectOpResult result;
return SetPrototype(cx, obj, proto, result) && result.checkStrict(cx, obj);
}
/**
* IsTypedArrayFixedLength ( O )
*
* ES2025 draft rev 3e6f71c9402f91344ef9560425cc1e8fc45abf86
*/
static bool IsTypedArrayFixedLength(ResizableTypedArrayObject* obj) {
MOZ_ASSERT(obj->hasResizableBuffer());
// Step 1.
if (obj->isAutoLength()) {
return false;
}
// Steps 2-4.
return obj->isSharedMemory();
}
bool js::PreventExtensions(JSContext* cx, HandleObject obj,
ObjectOpResult& result) {
if (obj->is<ProxyObject>()) {
return js::Proxy::preventExtensions(cx, obj, result);
}
if (obj->is<WasmGcObject>()) {
return result.failCantPreventExtensions();
}
if (obj->is<ResizableTypedArrayObject>() &&
!IsTypedArrayFixedLength(&obj->as<ResizableTypedArrayObject>())) {
return result.failCantPreventExtensions();
}
if (!obj->nonProxyIsExtensible()) {
// If the following assertion fails, there's somewhere else a missing
// call to shrinkCapacityToInitializedLength() which needs to be found
// and fixed.
MOZ_ASSERT_IF(obj->is<NativeObject>(),
obj->as<NativeObject>().getDenseInitializedLength() ==
obj->as<NativeObject>().getDenseCapacity());
return result.succeed();
}
if (obj->is<NativeObject>()) {
// Force lazy properties to be resolved.
Handle<NativeObject*> nobj = obj.as<NativeObject>();
if (!ResolveLazyProperties(cx, nobj)) {
return false;
}
// Prepare the elements. We have to do this before we mark the object
// non-extensible; that's fine because these changes are not observable.
ObjectElements::PrepareForPreventExtensions(cx, nobj);
}
// Finally, set the NotExtensible flag on the Shape and ObjectElements.
if (!JSObject::setFlag(cx, obj, ObjectFlag::NotExtensible)) {
return false;
}
if (obj->is<NativeObject>()) {
ObjectElements::PreventExtensions(&obj->as<NativeObject>());
}
return result.succeed();
}
bool js::PreventExtensions(JSContext* cx, HandleObject obj) {
ObjectOpResult result;
return PreventExtensions(cx, obj, result) && result.checkStrict(cx, obj);
}
bool js::GetOwnPropertyDescriptor(
JSContext* cx, HandleObject obj, HandleId id,
MutableHandle<Maybe<PropertyDescriptor>> desc) {
if (GetOwnPropertyOp op = obj->getOpsGetOwnPropertyDescriptor()) {
bool ok = op(cx, obj, id, desc);
if (ok && desc.isSome()) {
desc->assertComplete();
}
return ok;
}
return NativeGetOwnPropertyDescriptor(cx, obj.as<NativeObject>(), id, desc);
}
bool js::DefineProperty(JSContext* cx, HandleObject obj, HandleId id,
Handle<PropertyDescriptor> desc) {
ObjectOpResult result;
return DefineProperty(cx, obj, id, desc, result) &&
result.checkStrict(cx, obj, id);
}
bool js::DefineProperty(JSContext* cx, HandleObject obj, HandleId id,
Handle<PropertyDescriptor> desc,
ObjectOpResult& result) {
desc.assertValid();
if (DefinePropertyOp op = obj->getOpsDefineProperty()) {
return op(cx, obj, id, desc, result);
}
return NativeDefineProperty(cx, obj.as<NativeObject>(), id, desc, result);
}
bool js::DefineAccessorProperty(JSContext* cx, HandleObject obj, HandleId id,
HandleObject getter, HandleObject setter,
unsigned attrs, ObjectOpResult& result) {
Rooted<PropertyDescriptor> desc(
cx, PropertyDescriptor::Accessor(
getter ? mozilla::Some(getter) : mozilla::Nothing(),
setter ? mozilla::Some(setter) : mozilla::Nothing(), attrs));
if (DefinePropertyOp op = obj->getOpsDefineProperty()) {
return op(cx, obj, id, desc, result);
}
return NativeDefineProperty(cx, obj.as<NativeObject>(), id, desc, result);
}
bool js::DefineDataProperty(JSContext* cx, HandleObject obj, HandleId id,
HandleValue value, unsigned attrs,
ObjectOpResult& result) {
Rooted<PropertyDescriptor> desc(cx, PropertyDescriptor::Data(value, attrs));
if (DefinePropertyOp op = obj->getOpsDefineProperty()) {
return op(cx, obj, id, desc, result);
}
return NativeDefineProperty(cx, obj.as<NativeObject>(), id, desc, result);
}
bool js::DefineAccessorProperty(JSContext* cx, HandleObject obj, HandleId id,
HandleObject getter, HandleObject setter,
unsigned attrs) {
ObjectOpResult result;
if (!DefineAccessorProperty(cx, obj, id, getter, setter, attrs, result)) {
return false;
}
if (!result) {
result.reportError(cx, obj, id);
return false;
}
return true;
}
bool js::DefineDataProperty(JSContext* cx, HandleObject obj, HandleId id,
HandleValue value, unsigned attrs) {
ObjectOpResult result;
if (!DefineDataProperty(cx, obj, id, value, attrs, result)) {
return false;
}
if (!result) {
result.reportError(cx, obj, id);
return false;
}
return true;
}
bool js::DefineDataProperty(JSContext* cx, HandleObject obj, PropertyName* name,
HandleValue value, unsigned attrs) {
RootedId id(cx, NameToId(name));
return DefineDataProperty(cx, obj, id, value, attrs);
}
bool js::DefineDataElement(JSContext* cx, HandleObject obj, uint32_t index,
HandleValue value, unsigned attrs) {
RootedId id(cx);
if (!IndexToId(cx, index, &id)) {
return false;
}
return DefineDataProperty(cx, obj, id, value, attrs);
}
/*** SpiderMonkey nonstandard internal methods ******************************/
// Mark an object as having an immutable prototype
//
// NOTE: This does not correspond to the SetImmutablePrototype ECMAScript
// method.
bool js::SetImmutablePrototype(JSContext* cx, HandleObject obj,
bool* succeeded) {
if (obj->hasDynamicPrototype()) {
return Proxy::setImmutablePrototype(cx, obj, succeeded);
}
if (!JSObject::setFlag(cx, obj, ObjectFlag::ImmutablePrototype)) {
return false;
}
*succeeded = true;
return true;
}
bool js::GetPropertyDescriptor(
JSContext* cx, HandleObject obj, HandleId id,
MutableHandle<mozilla::Maybe<PropertyDescriptor>> desc,
MutableHandleObject holder) {
RootedObject pobj(cx);
for (pobj = obj; pobj;) {
if (!GetOwnPropertyDescriptor(cx, pobj, id, desc)) {
return false;
}
if (desc.isSome()) {
holder.set(pobj);
return true;
}
if (!GetPrototype(cx, pobj, &pobj)) {
return false;
}
}
MOZ_ASSERT(desc.isNothing());
holder.set(nullptr);
return true;
}
/* * */
extern bool PropertySpecNameToId(JSContext* cx, JSPropertySpec::Name name,
MutableHandleId id);
// If a property or method is part of an experimental feature that can be
// disabled at run-time by a preference, we keep it in the JSFunctionSpec /
// JSPropertySpec list, but omit the definition if the preference is off.
JS_PUBLIC_API bool js::ShouldIgnorePropertyDefinition(JSContext* cx,
JSProtoKey key, jsid id) {
if (!cx->realm()->creationOptions().getToSourceEnabled() &&
(id == NameToId(cx->names().toSource) ||
id == NameToId(cx->names().uneval))) {
return true;
}
if (key == JSProto_FinalizationRegistry &&
JS::GetWeakRefsEnabled() ==
JS::WeakRefSpecifier::EnabledWithoutCleanupSome &&
id == NameToId(cx->names().cleanupSome)) {
return true;
}
// It's gently surprising that this is JSProto_Function, but the trick
// to realize is that this is a -constructor function-, not a function
// on the prototype; and the proto of the constructor is JSProto_Function.
if (key == JSProto_Function && !JS::Prefs::array_grouping() &&
(id == NameToId(cx->names().groupBy))) {
return true;
}
if (key == JSProto_Set && !JS::Prefs::experimental_new_set_methods() &&
(id == NameToId(cx->names().union_) ||
id == NameToId(cx->names().difference) ||
id == NameToId(cx->names().intersection) ||
id == NameToId(cx->names().isSubsetOf) ||
id == NameToId(cx->names().isSupersetOf) ||
id == NameToId(cx->names().isDisjointFrom) ||
id == NameToId(cx->names().symmetricDifference))) {
return true;
}
if (key == JSProto_ArrayBuffer &&
!JS::Prefs::experimental_arraybuffer_resizable() &&
(id == NameToId(cx->names().maxByteLength) ||
id == NameToId(cx->names().resizable) ||
id == NameToId(cx->names().resize))) {
return true;
}
if (key == JSProto_SharedArrayBuffer &&
!JS::Prefs::experimental_sharedarraybuffer_growable() &&
(id == NameToId(cx->names().maxByteLength) ||
id == NameToId(cx->names().growable) ||
id == NameToId(cx->names().grow))) {
return true;
}
if (key == JSProto_ArrayBuffer && !JS::Prefs::arraybuffer_transfer() &&
(id == NameToId(cx->names().transfer) ||
id == NameToId(cx->names().transferToFixedLength) ||
id == NameToId(cx->names().detached))) {
return true;
}
if (key == JSProto_Uint8Array &&
!JS::Prefs::experimental_uint8array_base64() &&
(id == NameToId(cx->names().setFromBase64) ||
id == NameToId(cx->names().setFromHex) ||
id == NameToId(cx->names().toBase64) ||
id == NameToId(cx->names().toHex))) {
return true;
}
// It's gently surprising that this is JSProto_Function, but the trick
// to realize is that this is a -constructor function-, not a function
// on the prototype; and the proto of the constructor is JSProto_Function.
if (key == JSProto_Function && !JS::Prefs::experimental_uint8array_base64() &&
(id == NameToId(cx->names().fromBase64) ||
id == NameToId(cx->names().fromHex))) {
return true;
}
// It's gently surprising that this is JSProto_Function, but the trick
// to realize is that this is a -constructor function-, not a function
// on the prototype; and the proto of the constructor is JSProto_Function.
if (key == JSProto_Function && !JS::Prefs::experimental_promise_try() &&
id == NameToId(cx->names().try_)) {
return true;
}
// It's gently surprising that this is JSProto_Function, but the trick
// to realize is that this is a -constructor function-, not a function
// on the prototype; and the proto of the constructor is JSProto_Function.
if (key == JSProto_Function && !JS::Prefs::experimental_regexp_escape() &&
id == NameToId(cx->names().escape)) {
return true;
}
#ifdef NIGHTLY_BUILD
if (key == JSProto_Math && !JS::Prefs::experimental_math_sumprecise() &&
id == NameToId(cx->names().sumPrecise)) {
return true;
}
// It's gently surprising that this is JSProto_Function, but the trick
// to realize is that this is a -constructor function-, not a function
// on the prototype; and the proto of the constructor is JSProto_Function.
if (key == JSProto_Function && !JS::Prefs::experimental_error_iserror() &&
id == NameToId(cx->names().isError)) {
return true;
}
// It's gently surprising that this is JSProto_Function, but the trick
// to realize is that this is a -constructor function-, not a function
// on the prototype; and the proto of the constructor is JSProto_Function.
if (key == JSProto_Function && !JS::Prefs::experimental_iterator_range() &&
(id == NameToId(cx->names().range))) {
return true;
}
// It's gently surprising that this is JSProto_Function, but the trick
// to realize is that this is a -constructor function-, not a function
// on the prototype; and the proto of the constructor is JSProto_Function.
if (key == JSProto_Function && !JS::Prefs::experimental_joint_iteration() &&
(id == NameToId(cx->names().zip) ||
id == NameToId(cx->names().zipKeyed))) {
return true;
}
// It's gently surprising that this is JSProto_Function, but the trick
// to realize is that this is a -constructor function-, not a function
// on the prototype; and the proto of the constructor is JSProto_Function.
if (key == JSProto_Function &&
!JS::Prefs::experimental_iterator_sequencing() &&
id == NameToId(cx->names().concat)) {
return true;
}
if (key == JSProto_Atomics && !JS::Prefs::experimental_atomics_pause() &&
id == NameToId(cx->names().pause)) {
return true;
}
#endif
if (key == JSProto_JSON &&
!JS::Prefs::experimental_json_parse_with_source() &&
(id == NameToId(cx->names().isRawJSON) ||
id == NameToId(cx->names().rawJSON))) {
return true;
}
if (key == JSProto_Math && !JS::Prefs::experimental_float16array() &&
(id == NameToId(cx->names().f16round))) {
return true;
}
if (key == JSProto_DataView && !JS::Prefs::experimental_float16array() &&
(id == NameToId(cx->names().getFloat16) ||
id == NameToId(cx->names().setFloat16))) {
return true;
}
return false;
}
static bool DefineFunctionFromSpec(JSContext* cx, HandleObject obj,
const JSFunctionSpec* fs) {
RootedId id(cx);
if (!PropertySpecNameToId(cx, fs->name, &id)) {
return false;
}
if (ShouldIgnorePropertyDefinition(cx, StandardProtoKeyOrNull(obj), id)) {
return true;
}
JSFunction* fun = NewFunctionFromSpec(cx, fs, id);
if (!fun) {
return false;
}
RootedValue funVal(cx, ObjectValue(*fun));
return DefineDataProperty(cx, obj, id, funVal, fs->flags & ~JSFUN_FLAGS_MASK);
}
bool js::DefineFunctions(JSContext* cx, HandleObject obj,
const JSFunctionSpec* fs) {
for (; fs->name; fs++) {
if (!DefineFunctionFromSpec(cx, obj, fs)) {
return false;
}
}
return true;
}
/*** ToPrimitive ************************************************************/
/*
* Gets |obj[id]|. If that value's not callable, returns true and stores an
* object value in *vp. If it's callable, calls it with no arguments and |obj|
* as |this|, returning the result in *vp.
*
* This is a mini-abstraction for ES6 draft rev 36 (2015 Mar 17),
* 7.1.1, second algorithm (OrdinaryToPrimitive), steps 5.a-c.
*/
static bool MaybeCallMethod(JSContext* cx, HandleObject obj, HandleId id,
MutableHandleValue vp) {
if (!GetProperty(cx, obj, obj, id, vp)) {
return false;
}
if (!IsCallable(vp)) {
vp.setObject(*obj);
return true;
}
return js::Call(cx, vp, obj, vp);
}
static bool ReportCantConvert(JSContext* cx, unsigned errorNumber,
HandleObject obj, JSType hint) {
const JSClass* clasp = obj->getClass();
// Avoid recursive death when decompiling in ReportValueError.
RootedString str(cx);
if (hint == JSTYPE_STRING) {
str = JS_AtomizeString(cx, clasp->name);
if (!str) {
return false;
}
} else {
str = nullptr;
}
RootedValue val(cx, ObjectValue(*obj));
ReportValueError(cx, errorNumber, JSDVG_SEARCH_STACK, val, str,
hint == JSTYPE_UNDEFINED ? "primitive type"
: hint == JSTYPE_STRING ? "string"
: "number");
return false;
}
bool JS::OrdinaryToPrimitive(JSContext* cx, HandleObject obj, JSType hint,
MutableHandleValue vp) {
MOZ_ASSERT(hint == JSTYPE_NUMBER || hint == JSTYPE_STRING ||
hint == JSTYPE_UNDEFINED);
Rooted<jsid> id(cx);
const JSClass* clasp = obj->getClass();
if (hint == JSTYPE_STRING) {
id = NameToId(cx->names().toString);
bool calledToString = false;
if (clasp == &StringObject::class_) {
// Optimize (new String(...)).toString().
StringObject* nobj = &obj->as<StringObject>();
if (HasNativeMethodPure(nobj, cx->names().toString, str_toString, cx)) {
vp.setString(nobj->unbox());
return true;
}
} else if (clasp == &PlainObject::class_) {
JSFunction* fun;
if (GetPropertyPure(cx, obj, id, vp.address()) &&
IsFunctionObject(vp, &fun)) {
// Common case: we have a toString function. Try to short-circuit if
// it's Object.prototype.toString and there's no @@toStringTag.
if (fun->maybeNative() == obj_toString &&
!MaybeHasInterestingSymbolProperty(
cx, obj, cx->wellKnownSymbols().toStringTag)) {
vp.setString(cx->names().object_Object_);
return true;
}
if (!js::Call(cx, vp, obj, vp)) {
return false;
}
calledToString = true;
}
}
if (!calledToString) {
if (!MaybeCallMethod(cx, obj, id, vp)) {
return false;
}
}
if (vp.isPrimitive()) {
return true;
}
id = NameToId(cx->names().valueOf);
if (!MaybeCallMethod(cx, obj, id, vp)) {
return false;
}
if (vp.isPrimitive()) {
return true;
}
} else {
id = NameToId(cx->names().valueOf);
if (clasp == &StringObject::class_) {
// Optimize new String(...).valueOf().
StringObject* nobj = &obj->as<StringObject>();
if (HasNativeMethodPure(nobj, cx->names().valueOf, str_toString, cx)) {
vp.setString(nobj->unbox());
return true;
}
} else if (clasp == &NumberObject::class_) {
// Optimize new Number(...).valueOf().
NumberObject* nobj = &obj->as<NumberObject>();
if (HasNativeMethodPure(nobj, cx->names().valueOf, num_valueOf, cx)) {
vp.setNumber(nobj->unbox());
return true;
}
} else if (clasp == &DateObject::class_) {
DateObject* dateObj = &obj->as<DateObject>();
if (HasNativeMethodPure(dateObj, cx->names().valueOf, date_valueOf, cx)) {
vp.set(dateObj->UTCTime());
return true;
}
}
if (!MaybeCallMethod(cx, obj, id, vp)) {
return false;
}
if (vp.isPrimitive()) {
return true;
}
id = NameToId(cx->names().toString);
if (!MaybeCallMethod(cx, obj, id, vp)) {
return false;
}
if (vp.isPrimitive()) {
return true;
}
}
return ReportCantConvert(cx, JSMSG_CANT_CONVERT_TO, obj, hint);
}
bool js::ToPrimitiveSlow(JSContext* cx, JSType preferredType,
MutableHandleValue vp) {
// Step numbers refer to the first algorithm listed in ES6 draft rev 36
// (2015 Mar 17) 7.1.1 ToPrimitive.
MOZ_ASSERT(preferredType == JSTYPE_UNDEFINED ||
preferredType == JSTYPE_STRING || preferredType == JSTYPE_NUMBER);
RootedObject obj(cx, &vp.toObject());
// Steps 4-5.
RootedValue method(cx);
if (!GetInterestingSymbolProperty(cx, obj, cx->wellKnownSymbols().toPrimitive,
&method)) {
return false;
}
// Step 6.
if (!method.isNullOrUndefined()) {
// Step 6 of GetMethod. js::Call() below would do this check and throw a
// TypeError anyway, but this produces a better error message.
if (!IsCallable(method)) {
return ReportCantConvert(cx, JSMSG_TOPRIMITIVE_NOT_CALLABLE, obj,
preferredType);
}
// Steps 1-3, 6.a-b.
RootedValue arg0(
cx,
StringValue(preferredType == JSTYPE_STRING ? cx->names().string
: preferredType == JSTYPE_NUMBER ? cx->names().number
: cx->names().default_));
if (!js::Call(cx, method, vp, arg0, vp)) {
return false;
}
// Steps 6.c-d.
if (vp.isObject()) {
return ReportCantConvert(cx, JSMSG_TOPRIMITIVE_RETURNED_OBJECT, obj,
preferredType);
}
return true;
}
return OrdinaryToPrimitive(cx, obj, preferredType, vp);
}
/* ES6 draft rev 28 (2014 Oct 14) 7.1.14 */
bool js::ToPropertyKeySlow(JSContext* cx, HandleValue argument,
MutableHandleId result) {
MOZ_ASSERT(argument.isObject());
// Steps 1-2.
RootedValue key(cx, argument);
if (!ToPrimitiveSlow(cx, JSTYPE_STRING, &key)) {
return false;
}
// Steps 3-4.
return PrimitiveValueToId<CanGC>(cx, key, result);
}
/* * */
bool js::IsPrototypeOf(JSContext* cx, HandleObject protoObj, JSObject* obj,
bool* result) {
RootedObject obj2(cx, obj);
for (;;) {
// The [[Prototype]] chain might be cyclic.
if (!CheckForInterrupt(cx)) {
return false;
}
if (!GetPrototype(cx, obj2, &obj2)) {
return false;
}
if (!obj2) {
*result = false;
return true;
}
if (obj2 == protoObj) {
*result = true;
return true;
}
}
}
JSObject* js::PrimitiveToObject(JSContext* cx, const Value& v) {
MOZ_ASSERT(v.isPrimitive());
switch (v.type()) {
case ValueType::String: {
Rooted<JSString*> str(cx, v.toString());
return StringObject::create(cx, str);
}
case ValueType::Double:
case ValueType::Int32:
return NumberObject::create(cx, v.toNumber());
case ValueType::Boolean:
return BooleanObject::create(cx, v.toBoolean());
case ValueType::Symbol: {
RootedSymbol symbol(cx, v.toSymbol());
return SymbolObject::create(cx, symbol);
}
case ValueType::BigInt: {
RootedBigInt bigInt(cx, v.toBigInt());
return BigIntObject::create(cx, bigInt);
}
#ifdef ENABLE_RECORD_TUPLE
case ValueType::ExtendedPrimitive: {
JSObject& obj = v.toExtendedPrimitive();
if (obj.is<RecordType>()) {
Rooted<RecordType*> rec(cx, &obj.as<RecordType>());
return RecordObject::create(cx, rec);
}
if (obj.is<TupleType>()) {
Rooted<TupleType*> tuple(cx, &obj.as<TupleType>());
return TupleObject::create(cx, tuple);
}
MOZ_CRASH("Unexpected ExtendedPrimitive type.");
}
#endif
case ValueType::Undefined:
case ValueType::Null:
case ValueType::Magic:
case ValueType::PrivateGCThing:
case ValueType::Object:
break;
}
MOZ_CRASH("unexpected type");
}
// Like PrimitiveToObject, but returns the JSProtoKey of the prototype that
// would be used without actually creating the object.
JSProtoKey js::PrimitiveToProtoKey(JSContext* cx, const Value& v) {
MOZ_ASSERT(v.isPrimitive());
switch (v.type()) {
case ValueType::String:
return JSProto_String;
case ValueType::Double:
case ValueType::Int32:
return JSProto_Number;
case ValueType::Boolean:
return JSProto_Boolean;
case ValueType::Symbol:
return JSProto_Symbol;
case ValueType::BigInt:
return JSProto_BigInt;
#ifdef ENABLE_RECORD_TUPLE
case ValueType::ExtendedPrimitive:
if (v.toExtendedPrimitive().is<TupleType>()) {
return JSProto_Tuple;
}
if (v.toExtendedPrimitive().is<RecordType>()) {
return JSProto_Null;
}
MOZ_CRASH("Unsupported ExtendedPrimitive");
#endif
case ValueType::Undefined:
case ValueType::Null:
case ValueType::Magic:
case ValueType::PrivateGCThing:
case ValueType::Object:
break;
}
MOZ_CRASH("unexpected type");
}
/*
* Invokes the ES5 ToObject algorithm on vp, returning the result. If vp might
* already be an object, use ToObject. reportScanStack controls how null and
* undefined errors are reported.
*
* Callers must handle the already-object case.
*/
JSObject* js::ToObjectSlow(JSContext* cx, JS::HandleValue val,
bool reportScanStack) {
MOZ_ASSERT(!val.isMagic());
MOZ_ASSERT(!val.isObject());
if (val.isNullOrUndefined()) {
ReportIsNullOrUndefinedForPropertyAccess(
cx, val, reportScanStack ? JSDVG_SEARCH_STACK : JSDVG_IGNORE_STACK);
return nullptr;
}
return PrimitiveToObject(cx, val);
}
JSObject* js::ToObjectSlowForPropertyAccess(JSContext* cx, JS::HandleValue val,
int valIndex, HandleId key) {
MOZ_ASSERT(!val.isMagic());
MOZ_ASSERT(!val.isObject());
if (val.isNullOrUndefined()) {
ReportIsNullOrUndefinedForPropertyAccess(cx, val, valIndex, key);
return nullptr;
}
return PrimitiveToObject(cx, val);
}
JSObject* js::ToObjectSlowForPropertyAccess(JSContext* cx, JS::HandleValue val,
int valIndex,
Handle<PropertyName*> key) {
MOZ_ASSERT(!val.isMagic());
MOZ_ASSERT(!val.isObject());
if (val.isNullOrUndefined()) {
RootedId keyId(cx, NameToId(key));
ReportIsNullOrUndefinedForPropertyAccess(cx, val, valIndex, keyId);
return nullptr;
}
return PrimitiveToObject(cx, val);
}
JSObject* js::ToObjectSlowForPropertyAccess(JSContext* cx, JS::HandleValue val,
int valIndex,
HandleValue keyValue) {
MOZ_ASSERT(!val.isMagic());
MOZ_ASSERT(!val.isObject());
if (val.isNullOrUndefined()) {
RootedId key(cx);
if (keyValue.isPrimitive()) {
if (!PrimitiveValueToId<CanGC>(cx, keyValue, &key)) {
return nullptr;
}
ReportIsNullOrUndefinedForPropertyAccess(cx, val, valIndex, key);
} else {
ReportIsNullOrUndefinedForPropertyAccess(cx, val, valIndex);
}
return nullptr;
}
return PrimitiveToObject(cx, val);
}
class GetObjectSlotNameFunctor : public JS::TracingContext::Functor {
JSObject* obj;
public:
explicit GetObjectSlotNameFunctor(JSObject* ctx) : obj(ctx) {}
virtual void operator()(JS::TracingContext* trc, const char* name, char* buf,
size_t bufsize) override;
};
void GetObjectSlotNameFunctor::operator()(JS::TracingContext* tcx,
const char* name, char* buf,
size_t bufsize) {
MOZ_ASSERT(tcx->index() != JS::TracingContext::InvalidIndex);
uint32_t slot = uint32_t(tcx->index());
Maybe<PropertyKey> key;
if (obj->is<NativeObject>()) {
NativeShape* shape = obj->as<NativeObject>().shape();
for (ShapePropertyIter<NoGC> iter(shape); !iter.done(); iter++) {
if (iter->hasSlot() && iter->slot() == slot) {
key.emplace(iter->key());
break;
}
}
}
if (key.isNothing()) {
do {
const char* slotname = nullptr;
const char* pattern = nullptr;
if (obj->is<GlobalObject>()) {
pattern = "CLASS_OBJECT(%s)";
if (false) {
;
}
#define TEST_SLOT_MATCHES_PROTOTYPE(name, clasp) \
else if ((JSProto_##name) == slot){slotname = #name; \
}
JS_FOR_EACH_PROTOTYPE(TEST_SLOT_MATCHES_PROTOTYPE)
#undef TEST_SLOT_MATCHES_PROTOTYPE
} else {
pattern = "%s";
if (obj->is<EnvironmentObject>()) {
if (slot == EnvironmentObject::enclosingEnvironmentSlot()) {
slotname = "enclosing_environment";
} else if (obj->is<CallObject>()) {
if (slot == CallObject::calleeSlot()) {
slotname = "callee_slot";
}
} else if (obj->is<WithEnvironmentObject>()) {
if (slot == WithEnvironmentObject::objectSlot()) {
slotname = "with_object";
} else if (slot == WithEnvironmentObject::thisSlot()) {
slotname = "with_this";
}
}
}
}
if (slotname) {
snprintf(buf, bufsize, pattern, slotname);
} else {
snprintf(buf, bufsize, "**UNKNOWN SLOT %" PRIu32 "**", slot);
}
} while (false);
} else {
if (key->isInt()) {
snprintf(buf, bufsize, "%" PRId32, key->toInt());
} else if (key->isAtom()) {
PutEscapedString(buf, bufsize, key->toAtom(), 0);
} else if (key->isSymbol()) {
snprintf(buf, bufsize, "**SYMBOL KEY**");
} else {
snprintf(buf, bufsize, "**FINALIZED ATOM KEY**");
}
}
}
/*** Debugging routines *****************************************************/
#if defined(DEBUG) || defined(JS_JITSPEW)
/*
* Routines to print out values during debugging. These are JS_PUBLIC_API to
* help the debugger find them and to support temporarily hacking js::Dump*
* calls into other code.
*/
namespace js {
// We don't want jsfriendapi.h to depend on GenericPrinter,
// so these functions are declared directly in the cpp.
JS_PUBLIC_API void DumpValue(const JS::Value& val, js::GenericPrinter& out);
JS_PUBLIC_API void DumpId(jsid id, js::GenericPrinter& out);
JS_PUBLIC_API void DumpInterpreterFrame(JSContext* cx, js::GenericPrinter& out,
InterpreterFrame* start = nullptr);
} // namespace js
JS_PUBLIC_API void js::DumpValue(const Value& val, js::GenericPrinter& out) {
val.dump(out);
}
JS_PUBLIC_API void js::DumpId(jsid id, js::GenericPrinter& out) {
out.printf("jsid %p = ", (void*)id.asRawBits());
id.dump(out);
}
bool JSObject::hasSameRealmAs(JSContext* cx) const {
return nonCCWRealm() == cx->realm();
}
bool JSObject::uninlinedIsProxyObject() const { return is<ProxyObject>(); }
bool JSObject::uninlinedNonProxyIsExtensible() const {
return nonProxyIsExtensible();
}
void JSObject::dump() const {
js::Fprinter out(stderr);
dump(out);
}
void JSObject::dump(js::GenericPrinter& out) const {
js::JSONPrinter json(out);
dump(json);
out.put("\n");
}
void JSObject::dump(js::JSONPrinter& json) const {
json.beginObject();
dumpFields(json);
json.endObject();
}
# define FOR_EACH_CLASS(M) \
M(ArrayBufferViewObject) \
M(ArrayBufferObject) \
M(JSFunction) \
M(PromiseObject) \
M(RegExpObject)
static void DumpOwnFields(const JSObject* obj, js::JSONPrinter& json) {
# define CALL(CLASS) \
if (obj->is<CLASS>()) { \
obj->as<CLASS>().dumpOwnFields(json); \
return; \
}
FOR_EACH_CLASS(CALL)
# undef CALL
}
static void DumpOwnStringContent(const JSObject* obj, js::GenericPrinter& out) {
# define CALL(CLASS) \
if (obj->is<CLASS>()) { \
out.put(" "); \
obj->as<CLASS>().dumpOwnStringContent(out); \
return; \
}
FOR_EACH_CLASS(CALL)
# undef CALL
}
# undef FOR_EACH_CLASS
void JSObject::dumpFields(js::JSONPrinter& json) const {
json.formatProperty("address", "(JSObject*)0x%p", this);
if (IsCrossCompartmentWrapper(this)) {
json.formatProperty("compartment", "(JS::Compartment*)0x%p", compartment());
} else {
JSObject* globalObj = &nonCCWGlobal();
js::GenericPrinter& out = json.beginStringProperty("nonCCWGlobal");
globalObj->dumpStringContent(out);
json.endStringProperty();
}
const JSClass* clasp = getClass();
json.formatProperty("clasp", "<%s @ (JSClass*)0x%p>", clasp->name, clasp);
js::GenericPrinter& out = json.beginStringProperty("shape");
shape()->dumpStringContent(out);
json.endStringProperty();
json.beginObjectProperty("shape.base");
shape()->base()->dumpFields(json);
json.endObject();
if (IsProxy(this)) {
const js::BaseProxyHandler* handler = GetProxyHandler(this);
if (IsDeadProxyObject(this)) {
json.formatProperty("handler", "(js::DeadObjectProxy*)0x%p", handler);
} else if (IsCrossCompartmentWrapper(this)) {
json.formatProperty("handler", "(js::CrossCompartmentWrapper*)0x%p",
handler);
} else {
json.formatProperty("handler", "(js::BaseProxyHandler*)0x%p", handler);
}
Value priv = GetProxyPrivate(this);
if (!priv.isUndefined()) {
js::GenericPrinter& out = json.beginStringProperty("private");
priv.dumpStringContent(out);
json.endStringProperty();
}
Value expando = GetProxyExpando(this);
if (!expando.isNull()) {
js::GenericPrinter& out = json.beginStringProperty("expando");
expando.dumpStringContent(out);
json.endStringProperty();
}
if (is<DebugEnvironmentProxy>()) {
json.boolProperty("isQualifiedVarObj", isQualifiedVarObj());
json.boolProperty("isUnqualifiedVarObj", isUnqualifiedVarObj());
}
}
DumpOwnFields(this, json);
if (is<NativeObject>()) {
const auto* nobj = &as<NativeObject>();
js::GenericPrinter& out = json.beginStringProperty("elementsHeader");
nobj->getElementsHeader()->dumpStringContent(out);
json.endStringProperty();
uint32_t reserved = JSCLASS_RESERVED_SLOTS(clasp);
if (reserved) {
char name[256];
json.beginObjectProperty("reservedSlots");
for (uint32_t i = 0; i < reserved; i++) {
SprintfLiteral(name, "%u", i);
js::GenericPrinter& out = json.beginStringProperty(name);
nobj->getSlot(i).dumpStringContent(out);
json.endStringProperty();
}
json.endObject();
}
json.beginObjectProperty("properties");
if (PropMap* map = nobj->shape()->propMap()) {
Vector<PropMap*, 8, SystemAllocPolicy> maps;
while (true) {
if (!maps.append(map)) {
json.property("error", "*oom in JSObject::dumpFields*");
break;
}
if (!map->hasPrevious()) {
break;
}
map = map->asLinked()->previous();
}
for (size_t i = maps.length(); i > 0; i--) {
size_t index = i - 1;
PropMap* map = maps[index];
uint32_t len = (index == 0) ? shape()->asNative().propMapLength()
: PropMap::Capacity;
for (uint32_t j = 0; j < len; j++) {
if (!map->hasKey(j)) {
MOZ_ASSERT(map->isDictionary());
continue;
}
JS::UniqueChars propChars = map->getPropertyNameAt(j);
if (!propChars) {
json.property("error", "*oom in PropMap::getPropertyNameAt*");
continue;
}
js::GenericPrinter& out = json.beginStringProperty(propChars.get());
PropertyInfoWithKey prop = map->getPropertyInfoWithKey(j);
if (prop.isDataProperty()) {
nobj->getSlot(prop.slot()).dumpStringContent(out);
out.put(" ");
} else if (prop.isAccessorProperty()) {
out.printf("getter=0x%p, setter=0x%p", nobj->getGetter(prop),
nobj->getSetter(prop));
out.put(" ");
}
out.put("(");
map->dumpDescriptorStringContentAt(out, j);
out.put(")");
json.endStringProperty();
}
}
}
json.endObject();
uint32_t slots = nobj->getDenseInitializedLength();
if (slots) {
char name[64];
json.beginObjectProperty("elements");
for (uint32_t i = 0; i < slots; i++) {
SprintfLiteral(name, "%u", i);
js::GenericPrinter& out = json.beginStringProperty(name);
nobj->getDenseElement(i).dumpStringContent(out);
json.endStringProperty();
}
json.endObject();
}
}
}
void JSObject::dumpStringContent(js::GenericPrinter& out) const {
out.printf("<%s", getClass()->name);
DumpOwnStringContent(this, out);
out.printf(" @ (JSObject*)0x%p>", this);
}
static void MaybeDumpScope(Scope* scope, js::GenericPrinter& out) {
if (scope) {
out.printf(" scope: %s\n", ScopeKindString(scope->kind()));
for (BindingIter bi(scope); bi; bi++) {
out.put(" ");
StringValue(bi.name()).dump(out);
}
}
}
static void MaybeDumpValue(const char* name, const Value& v,
js::GenericPrinter& out) {
if (!v.isNull()) {
out.printf(" %s: ", name);
v.dump(out);
}
}
JS_PUBLIC_API void js::DumpInterpreterFrame(JSContext* cx,
js::GenericPrinter& out,
InterpreterFrame* start) {
/* This should only called during live debugging. */
ScriptFrameIter i(cx);
if (!start) {
if (i.done()) {
out.printf("no stack for cx = %p\n", (void*)cx);
return;
}
} else {
while (!i.done() && !i.isJSJit() && i.interpFrame() != start) {
++i;
}
if (i.done()) {
out.printf("fp = %p not found in cx = %p\n", (void*)start, (void*)cx);
return;
}
}
for (; !i.done(); ++i) {
if (i.isJSJit()) {
out.put("JIT frame\n");
} else {
out.printf("InterpreterFrame at %p\n", (void*)i.interpFrame());
}
if (i.isFunctionFrame()) {
out.put("callee fun: ");
RootedValue v(cx);
JSObject* fun = i.callee(cx);
v.setObject(*fun);
v.get().dump(out);
} else {
out.put("global or eval frame, no callee\n");
}
out.printf("file %s line %u\n", i.script()->filename(),
i.script()->lineno());
if (jsbytecode* pc = i.pc()) {
out.printf(" pc = %p\n", pc);
out.printf(" current op: %s\n", CodeName(JSOp(*pc)));
MaybeDumpScope(i.script()->lookupScope(pc), out);
}
if (i.isFunctionFrame()) {
MaybeDumpValue("this", i.thisArgument(cx), out);
}
if (!i.isJSJit()) {
out.put(" rval: ");
i.interpFrame()->returnValue().get().dump(out);
}
out.put(" flags:");
if (i.isConstructing()) {
out.put(" constructing");
}
if (!i.isJSJit() && i.interpFrame()->isDebuggerEvalFrame()) {
out.put(" debugger eval");
}
if (i.isEvalFrame()) {
out.put(" eval");
}
out.putChar('\n');
out.printf(" envChain: (JSObject*) %p\n", (void*)i.environmentChain(cx));
out.putChar('\n');
}
}
#endif /* defined(DEBUG) || defined(JS_JITSPEW) */
JS_PUBLIC_API void js::DumpBacktrace(JSContext* cx, FILE* fp) {
Fprinter out(fp);
js::DumpBacktrace(cx, out);
}
JS_PUBLIC_API void js::DumpBacktrace(JSContext* cx, js::GenericPrinter& out) {
size_t depth = 0;
for (AllFramesIter i(cx); !i.done(); ++i, ++depth) {
const char* filename;
unsigned line;
if (i.hasScript()) {
filename = JS_GetScriptFilename(i.script());
line = PCToLineNumber(i.script(), i.pc());
} else {
filename = i.filename();
line = i.computeLine();
}
char frameType = i.isInterp() ? 'i'
: i.isBaseline() ? 'b'
: i.isIon() ? 'I'
: i.isWasm() ? 'W'
: '?';
out.printf("#%zu %14p %c %s:%u", depth, i.rawFramePtr(), frameType,
filename, line);
if (i.hasScript()) {
out.printf(" (%p @ %zu)\n", i.script(), i.script()->pcToOffset(i.pc()));
} else {
out.printf(" (%p)\n", i.pc());
}
}
}
JS_PUBLIC_API void js::DumpBacktrace(JSContext* cx) {
DumpBacktrace(cx, stdout);
}
/* * */
bool JSObject::isBackgroundFinalized() const {
if (isTenured()) {
return js::gc::IsBackgroundFinalized(asTenured().getAllocKind());
}
js::Nursery& nursery = runtimeFromMainThread()->gc.nursery();
return js::gc::IsBackgroundFinalized(allocKindForTenure(nursery));
}
js::gc::AllocKind JSObject::allocKindForTenure(
const js::Nursery& nursery) const {
using namespace js::gc;
MOZ_ASSERT(IsInsideNursery(this));
if (is<NativeObject>()) {
if (canHaveFixedElements()) {
const NativeObject& nobj = as<NativeObject>();
MOZ_ASSERT(nobj.numFixedSlots() == 0);
/* Use minimal size object if we are just going to copy the pointer. */
if (!nursery.isInside(nobj.getUnshiftedElementsHeader())) {
return gc::AllocKind::OBJECT0_BACKGROUND;
}
size_t nelements = nobj.getDenseCapacity();
return ForegroundToBackgroundAllocKind(GetGCArrayKind(nelements));
}
if (is<JSFunction>()) {
return as<JSFunction>().getAllocKind();
}
if (is<FixedLengthTypedArrayObject>()) {
return as<FixedLengthTypedArrayObject>().allocKindForTenure();
}
return as<NativeObject>().allocKindForTenure();
}
// Handle all non-native objects.
// Proxies that are CrossCompartmentWrappers may be nursery allocated.
if (is<ProxyObject>()) {
return as<ProxyObject>().allocKindForTenure();
}
// WasmStructObjects have a variable-length tail which contains the first
// few data fields, so make sure we copy it all over to the new object.
if (is<WasmStructObject>()) {
// Figure out the size of this object, from the object's TypeDef.
const wasm::TypeDef* typeDef = &as<WasmStructObject>().typeDef();
return WasmStructObject::allocKindForTypeDef(typeDef);
}
// WasmArrayObjects sometimes have a variable-length tail which contains the
// data for small arrays. Make sure we copy it all over to the new object.
MOZ_ASSERT(is<WasmArrayObject>());
gc::AllocKind allocKind = as<WasmArrayObject>().allocKind();
return allocKind;
}
void JSObject::addSizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf,
JS::ClassInfo* info,
JS::RuntimeSizes* runtimeSizes) {
if (is<NativeObject>() && as<NativeObject>().hasDynamicSlots()) {
info->objectsMallocHeapSlots +=
mallocSizeOf(as<NativeObject>().getSlotsHeader());
}
if (is<NativeObject>() && as<NativeObject>().hasDynamicElements()) {
void* allocatedElements = as<NativeObject>().getUnshiftedElementsHeader();
info->objectsMallocHeapElementsNormal += mallocSizeOf(allocatedElements);
}
// Other things may be measured in the future if DMD indicates it is
// worthwhile.
if (is<JSFunction>() || is<PlainObject>() || is<ArrayObject>() ||
is<CallObject>() || is<RegExpObject>() || is<ProxyObject>()) {
// Do nothing. But this function is hot, and we win by getting the
// common cases out of the way early. Some stats on the most common
// classes, as measured during a vanilla browser session:
// - (53.7%, 53.7%): Function
// - (18.0%, 71.7%): Object
// - (16.9%, 88.6%): Array
// - ( 3.9%, 92.5%): Call
// - ( 2.8%, 95.3%): RegExp
// - ( 1.0%, 96.4%): Proxy
// Note that any JSClass that is special cased below likely needs to
// specify the JSCLASS_DELAY_METADATA_BUILDER flag, or else we will
// probably crash if the object metadata callback attempts to get the
// size of the new object (which Debugger code does) before private
// slots are initialized.
} else if (is<ArgumentsObject>()) {
info->objectsMallocHeapMisc +=
as<ArgumentsObject>().sizeOfMisc(mallocSizeOf);
} else if (is<MapObject>()) {
info->objectsMallocHeapMisc += as<MapObject>().sizeOfData(mallocSizeOf);
} else if (is<SetObject>()) {
info->objectsMallocHeapMisc += as<SetObject>().sizeOfData(mallocSizeOf);
} else if (is<PropertyIteratorObject>()) {
info->objectsMallocHeapMisc +=
as<PropertyIteratorObject>().sizeOfMisc(mallocSizeOf);
} else if (is<ArrayBufferObject>()) {
ArrayBufferObject::addSizeOfExcludingThis(this, mallocSizeOf, info,
runtimeSizes);
} else if (is<SharedArrayBufferObject>()) {
SharedArrayBufferObject::addSizeOfExcludingThis(this, mallocSizeOf, info,
runtimeSizes);
} else if (is<GlobalObject>()) {
as<GlobalObject>().addSizeOfData(mallocSizeOf, info);
} else if (is<WeakCollectionObject>()) {
info->objectsMallocHeapMisc +=
as<WeakCollectionObject>().sizeOfExcludingThis(mallocSizeOf);
}
#ifdef JS_HAS_CTYPES
else {
// This must be the last case.
info->objectsMallocHeapMisc += ctypes::SizeOfDataIfCDataObject(
mallocSizeOf, const_cast<JSObject*>(this));
}
#endif
}
size_t JSObject::sizeOfIncludingThisInNursery() const {
// This function doesn't concern itself yet with typed objects (bug 1133593).
MOZ_ASSERT(!isTenured());
const Nursery& nursery = runtimeFromMainThread()->gc.nursery();
size_t size = gc::Arena::thingSize(allocKindForTenure(nursery));
if (is<NativeObject>()) {
const NativeObject& native = as<NativeObject>();
size += native.numDynamicSlots() * sizeof(Value);
if (native.hasDynamicElements()) {
js::ObjectElements& elements = *native.getElementsHeader();
size += (elements.capacity + elements.numShiftedElements()) *
sizeof(HeapSlot);
}
if (is<ArgumentsObject>()) {
size += as<ArgumentsObject>().sizeOfData();
}
}
return size;
}
JS::ubi::Node::Size JS::ubi::Concrete<JSObject>::size(
mozilla::MallocSizeOf mallocSizeOf) const {
JSObject& obj = get();
if (!obj.isTenured()) {
return obj.sizeOfIncludingThisInNursery();
}
JS::ClassInfo info;
obj.addSizeOfExcludingThis(mallocSizeOf, &info, nullptr);
return obj.tenuredSizeOfThis() + info.sizeOfAllThings();
}
const char16_t JS::ubi::Concrete<JSObject>::concreteTypeName[] = u"JSObject";
void JSObject::traceChildren(JSTracer* trc) {
TraceCellHeaderEdge(trc, this, "shape");
Shape* objShape = shape();
if (objShape->isNative()) {
NativeObject* nobj = &as<NativeObject>();
{
GetObjectSlotNameFunctor func(nobj);
JS::AutoTracingDetails ctx(trc, func);
JS::AutoTracingIndex index(trc);
// Tracing can mutate the target but cannot change the slot count,
// but the compiler has no way of knowing this.
const uint32_t nslots = nobj->slotSpan();
for (uint32_t i = 0; i < nslots; ++i) {
TraceEdge(trc, &nobj->getSlotRef(i), "object slot");
++index;
}
MOZ_ASSERT(nslots == nobj->slotSpan());
}
TraceRange(trc, nobj->getDenseInitializedLength(),
static_cast<HeapSlot*>(nobj->getDenseElements()),
"objectElements");
}
// Call the trace hook at the end so that during a moving GC the trace hook
// will see updated fields and slots.
const JSClass* clasp = objShape->getObjectClass();
if (clasp->hasTrace()) {
clasp->doTrace(trc, this);
}
}
// ES 2016 7.3.20.
[[nodiscard]] JSObject* js::SpeciesConstructor(
JSContext* cx, HandleObject obj, HandleObject defaultCtor,
bool (*isDefaultSpecies)(JSContext*, JSFunction*)) {
// Step 1 (implicit).
// Fast-path for steps 2 - 8. Applies if all of the following conditions
// are met:
// - obj.constructor can be retrieved without side-effects.
// - obj.constructor[[@@species]] can be retrieved without side-effects.
// - obj.constructor[[@@species]] is the builtin's original @@species
// getter.
RootedValue ctor(cx);
bool ctorGetSucceeded = GetPropertyPure(
cx, obj, NameToId(cx->names().constructor), ctor.address());
if (ctorGetSucceeded && ctor.isObject() && &ctor.toObject() == defaultCtor) {
jsid speciesId = PropertyKey::Symbol(cx->wellKnownSymbols().species);
JSFunction* getter;
if (GetGetterPure(cx, defaultCtor, speciesId, &getter) && getter &&
isDefaultSpecies(cx, getter)) {
return defaultCtor;
}
}
// Step 2.
if (!ctorGetSucceeded &&
!GetProperty(cx, obj, obj, cx->names().constructor, &ctor)) {
return nullptr;
}
// Step 3.
if (ctor.isUndefined()) {
return defaultCtor;
}
// Step 4.
if (!ctor.isObject()) {
JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr,
JSMSG_OBJECT_REQUIRED,
"object's 'constructor' property");
return nullptr;
}
// Step 5.
RootedObject ctorObj(cx, &ctor.toObject());
RootedValue s(cx);
RootedId speciesId(cx, PropertyKey::Symbol(cx->wellKnownSymbols().species));
if (!GetProperty(cx, ctorObj, ctor, speciesId, &s)) {
return nullptr;
}
// Step 6.
if (s.isNullOrUndefined()) {
return defaultCtor;
}
// Step 7.
if (IsConstructor(s)) {
return &s.toObject();
}
// Step 8.
JS_ReportErrorNumberASCII(
cx, GetErrorMessage, nullptr, JSMSG_NOT_CONSTRUCTOR,
"[Symbol.species] property of object's constructor");
return nullptr;
}
[[nodiscard]] JSObject* js::SpeciesConstructor(
JSContext* cx, HandleObject obj, JSProtoKey ctorKey,
bool (*isDefaultSpecies)(JSContext*, JSFunction*)) {
RootedObject defaultCtor(cx,
GlobalObject::getOrCreateConstructor(cx, ctorKey));
if (!defaultCtor) {
return nullptr;
}
return SpeciesConstructor(cx, obj, defaultCtor, isDefaultSpecies);
}
bool js::Unbox(JSContext* cx, HandleObject obj, MutableHandleValue vp) {
if (MOZ_UNLIKELY(obj->is<ProxyObject>())) {
return Proxy::boxedValue_unbox(cx, obj, vp);
}
if (obj->is<BooleanObject>()) {
vp.setBoolean(obj->as<BooleanObject>().unbox());
} else if (obj->is<NumberObject>()) {
vp.setNumber(obj->as<NumberObject>().unbox());
} else if (obj->is<StringObject>()) {
vp.setString(obj->as<StringObject>().unbox());
} else if (obj->is<DateObject>()) {
vp.set(obj->as<DateObject>().UTCTime());
} else if (obj->is<SymbolObject>()) {
vp.setSymbol(obj->as<SymbolObject>().unbox());
} else if (obj->is<BigIntObject>()) {
vp.setBigInt(obj->as<BigIntObject>().unbox());
#ifdef ENABLE_RECORD_TUPLE
} else if (obj->is<RecordObject>()) {
vp.setExtendedPrimitive(*obj->as<RecordObject>().unbox());
} else if (obj->is<TupleObject>()) {
vp.setExtendedPrimitive(obj->as<TupleObject>().unbox());
#endif
} else {
vp.setUndefined();
}
return true;
}
#ifdef DEBUG
void js::AssertJSClassInvariants(const JSClass* clasp) {
MOZ_ASSERT(JS::StringIsASCII(clasp->name));
// Native objects shouldn't use the property operation hooks in ObjectOps.
// Doing so could violate JIT invariants.
//
// Environment objects unfortunately use these hooks, but environment objects
// are not exposed directly to script so they're generally less of an issue.
if (clasp->isNativeObject() && clasp != &WithEnvironmentObject::class_ &&
clasp != &ModuleEnvironmentObject::class_ &&
clasp != &RuntimeLexicalErrorObject::class_) {
MOZ_ASSERT(!clasp->getOpsLookupProperty());
MOZ_ASSERT_IF(clasp != &MappedArgumentsObject::class_,
!clasp->getOpsDefineProperty());
MOZ_ASSERT(!clasp->getOpsHasProperty());
MOZ_ASSERT(!clasp->getOpsGetProperty());
MOZ_ASSERT(!clasp->getOpsSetProperty());
MOZ_ASSERT(!clasp->getOpsGetOwnPropertyDescriptor());
MOZ_ASSERT(!clasp->getOpsDeleteProperty());
}
}
/* static */
void JSObject::debugCheckNewObject(Shape* shape, js::gc::AllocKind allocKind,
js::gc::Heap heap) {
const JSClass* clasp = shape->getObjectClass();
if (!ClassCanHaveFixedData(clasp)) {
NativeShape* nshape = &shape->asNative();
if (clasp == &ArrayObject::class_) {
// Arrays can store the ObjectElements header inline.
MOZ_ASSERT(nshape->numFixedSlots() == 0);
} else {
MOZ_ASSERT(gc::GetGCKindSlots(allocKind) == nshape->numFixedSlots());
}
}
// Assert background finalization is used when possible.
MOZ_ASSERT(!CanChangeToBackgroundAllocKind(allocKind, clasp));
// Classes with a finalizer must specify whether instances will be finalized
// on the main thread or in the background, except proxies whose behaviour
// depends on the target object.
static const uint32_t FinalizeMask =
JSCLASS_FOREGROUND_FINALIZE | JSCLASS_BACKGROUND_FINALIZE;
uint32_t flags = clasp->flags;
uint32_t finalizeFlags = flags & FinalizeMask;
if (clasp->hasFinalize() && !clasp->isProxyObject()) {
MOZ_ASSERT(finalizeFlags == JSCLASS_FOREGROUND_FINALIZE ||
finalizeFlags == JSCLASS_BACKGROUND_FINALIZE);
MOZ_ASSERT((finalizeFlags == JSCLASS_BACKGROUND_FINALIZE) ==
IsBackgroundFinalized(allocKind));
} else {
MOZ_ASSERT(finalizeFlags == 0);
}
MOZ_ASSERT_IF(clasp->hasFinalize(),
heap == gc::Heap::Tenured ||
CanNurseryAllocateFinalizedClass(clasp) ||
clasp->isProxyObject());
MOZ_ASSERT(!shape->isDictionary());
MOZ_ASSERT(!shape->realm()->hasObjectPendingMetadata());
// Non-native classes manage their own data and slots, so numFixedSlots is
// always 0. Note that proxy classes can have reserved slots but they're not
// included in numFixedSlots.
if (!clasp->isNativeObject()) {
MOZ_ASSERT_IF(!clasp->isProxyObject(), JSCLASS_RESERVED_SLOTS(clasp) == 0);
}
}
#endif