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Diffstat (limited to '')
| -rw-r--r-- | js/src/vm/JSObject.cpp | 3951 |
1 files changed, 3951 insertions, 0 deletions
diff --git a/js/src/vm/JSObject.cpp b/js/src/vm/JSObject.cpp new file mode 100644 index 0000000000..cb78bfff69 --- /dev/null +++ b/js/src/vm/JSObject.cpp @@ -0,0 +1,3951 @@ +/* -*- 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/MathAlgorithms.h" +#include "mozilla/Maybe.h" +#include "mozilla/MemoryReporting.h" +#include "mozilla/TemplateLib.h" + +#include <algorithm> +#include <string.h> + +#include "jsapi.h" +#include "jsexn.h" +#include "jsfriendapi.h" +#include "jsnum.h" +#include "jstypes.h" + +#include "builtin/Array.h" +#include "builtin/BigInt.h" +#include "builtin/Eval.h" +#include "builtin/Object.h" +#include "builtin/String.h" +#include "builtin/Symbol.h" +#include "builtin/WeakSetObject.h" +#include "frontend/BytecodeCompiler.h" +#include "gc/Policy.h" +#include "jit/BaselineJIT.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/PropertyDescriptor.h" // JS::FromPropertyDescriptor +#include "js/PropertySpec.h" // JSPropertySpec +#include "js/Proxy.h" +#include "js/Result.h" +#include "js/UbiNode.h" +#include "js/UniquePtr.h" +#include "js/Wrapper.h" +#include "util/Memory.h" +#include "util/Text.h" +#include "util/Windows.h" +#include "vm/ArgumentsObject.h" +#include "vm/BytecodeUtil.h" +#include "vm/DateObject.h" +#include "vm/Interpreter.h" +#include "vm/Iteration.h" +#include "vm/JSAtom.h" +#include "vm/JSContext.h" +#include "vm/JSFunction.h" +#include "vm/JSScript.h" +#include "vm/ProxyObject.h" +#include "vm/RegExpStaticsObject.h" +#include "vm/Shape.h" +#include "vm/TypedArrayObject.h" + +#include "builtin/Boolean-inl.h" +#include "gc/Marking-inl.h" +#include "vm/ArrayObject-inl.h" +#include "vm/BooleanObject-inl.h" +#include "vm/Caches-inl.h" +#include "vm/Compartment-inl.h" +#include "vm/Interpreter-inl.h" +#include "vm/JSAtom-inl.h" +#include "vm/JSContext-inl.h" +#include "vm/JSFunction-inl.h" +#include "vm/NativeObject-inl.h" +#include "vm/NumberObject-inl.h" +#include "vm/PlainObject-inl.h" // js::CopyInitializerObject +#include "vm/Realm-inl.h" +#include "vm/Shape-inl.h" +#include "vm/StringObject-inl.h" +#include "vm/TypedArrayObject-inl.h" +#include "wasm/TypedObject-inl.h" + +using namespace js; + +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; + if (const char* chars = ValueToSourceForError(cx, v, bytes)) { + 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: + return v.toObject().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<PropertyDescriptor> desc, + MutableHandleValue vp) { + AssertHeapIsIdle(); + CHECK_THREAD(cx); + cx->check(desc); + + // Step 1. + if (!desc.object()) { + vp.setUndefined(); + return true; + } + + return FromPropertyDescriptorToObject(cx, desc, vp); +} + +bool js::FromPropertyDescriptorToObject(JSContext* cx, + Handle<PropertyDescriptor> desc, + MutableHandleValue vp) { + // Step 2-3. + RootedObject obj(cx, NewBuiltinClassInstance<PlainObject>(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.hasGetterObject()) { + if (JSObject* get = desc.getterObject()) { + v.setObject(*get); + } else { + v.setUndefined(); + } + if (!DefineDataProperty(cx, obj, names.get, v)) { + return false; + } + } + + // Step 7. + if (desc.hasSetterObject()) { + if (JSObject* set = desc.setterObject()) { + 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 const char js_getter_str[] = "getter"; +static const char js_setter_str[] = "setter"; + +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(); +} + +bool js::ToPropertyDescriptor(JSContext* cx, HandleValue descval, + bool checkAccessors, + MutableHandle<PropertyDescriptor> desc) { + // step 2 + RootedObject obj(cx, + RequireObject(cx, JSMSG_OBJECT_REQUIRED_PROP_DESC, descval)); + if (!obj) { + return false; + } + + // step 3 + desc.clear(); + + bool found = false; + RootedId id(cx); + RootedValue v(cx); + unsigned attrs = 0; + + // step 4 + id = NameToId(cx->names().enumerable); + if (!GetPropertyIfPresent(cx, obj, id, &v, &found)) { + return false; + } + if (found) { + if (ToBoolean(v)) { + attrs |= JSPROP_ENUMERATE; + } + } else { + attrs |= JSPROP_IGNORE_ENUMERATE; + } + + // step 5 + id = NameToId(cx->names().configurable); + if (!GetPropertyIfPresent(cx, obj, id, &v, &found)) { + return false; + } + if (found) { + if (!ToBoolean(v)) { + attrs |= JSPROP_PERMANENT; + } + } else { + attrs |= JSPROP_IGNORE_PERMANENT; + } + + // step 6 + id = NameToId(cx->names().value); + if (!GetPropertyIfPresent(cx, obj, id, &v, &found)) { + return false; + } + if (found) { + desc.value().set(v); + } else { + attrs |= JSPROP_IGNORE_VALUE; + } + + // step 7 + id = NameToId(cx->names().writable); + if (!GetPropertyIfPresent(cx, obj, id, &v, &found)) { + return false; + } + if (found) { + if (!ToBoolean(v)) { + attrs |= JSPROP_READONLY; + } + } else { + attrs |= JSPROP_IGNORE_READONLY; + } + + // step 8 + bool hasGetOrSet; + id = NameToId(cx->names().get); + if (!GetPropertyIfPresent(cx, obj, id, &v, &found)) { + return false; + } + hasGetOrSet = found; + if (found) { + if (v.isObject()) { + if (checkAccessors) { + JS_TRY_OR_RETURN_FALSE(cx, + CheckCallable(cx, &v.toObject(), js_getter_str)); + } + desc.setGetterObject(&v.toObject()); + } else if (!v.isUndefined()) { + JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, + JSMSG_BAD_GET_SET_FIELD, js_getter_str); + return false; + } + attrs |= JSPROP_GETTER; + } + + // step 9 + id = NameToId(cx->names().set); + if (!GetPropertyIfPresent(cx, obj, id, &v, &found)) { + return false; + } + hasGetOrSet |= found; + if (found) { + if (v.isObject()) { + if (checkAccessors) { + JS_TRY_OR_RETURN_FALSE(cx, + CheckCallable(cx, &v.toObject(), js_setter_str)); + } + desc.setSetterObject(&v.toObject()); + } else if (!v.isUndefined()) { + JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, + JSMSG_BAD_GET_SET_FIELD, js_setter_str); + return false; + } + attrs |= JSPROP_SETTER; + } + + // step 10 + if (hasGetOrSet) { + if (!(attrs & JSPROP_IGNORE_READONLY) || !(attrs & JSPROP_IGNORE_VALUE)) { + JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, + JSMSG_INVALID_DESCRIPTOR); + return false; + } + + // By convention, these bits are not used on accessor descriptors. + attrs &= ~(JSPROP_IGNORE_READONLY | JSPROP_IGNORE_VALUE); + } + + desc.setAttributes(attrs); + MOZ_ASSERT_IF(attrs & JSPROP_READONLY, + !(attrs & (JSPROP_GETTER | JSPROP_SETTER))); + return true; +} + +Result<> js::CheckPropertyDescriptorAccessors(JSContext* cx, + Handle<PropertyDescriptor> desc) { + if (desc.hasGetterObject()) { + MOZ_TRY(CheckCallable(cx, desc.getterObject(), js_getter_str)); + } + + if (desc.hasSetterObject()) { + MOZ_TRY(CheckCallable(cx, desc.setterObject(), js_setter_str)); + } + + return Ok(); +} + +void js::CompletePropertyDescriptor(MutableHandle<PropertyDescriptor> desc) { + desc.assertValid(); + + if (desc.isGenericDescriptor() || desc.isDataDescriptor()) { + if (!desc.hasWritable()) { + desc.attributesRef() |= JSPROP_READONLY; + } + desc.attributesRef() &= ~(JSPROP_IGNORE_READONLY | JSPROP_IGNORE_VALUE); + } else { + if (!desc.hasGetterObject()) { + desc.setGetterObject(nullptr); + } + if (!desc.hasSetterObject()) { + desc.setSetterObject(nullptr); + } + desc.attributesRef() |= JSPROP_GETTER | JSPROP_SETTER; + } + if (!desc.hasConfigurable()) { + desc.attributesRef() |= JSPROP_PERMANENT; + } + desc.attributesRef() &= ~(JSPROP_IGNORE_PERMANENT | JSPROP_IGNORE_ENUMERATE); + + 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 ********************************************************/ + +static unsigned GetSealedOrFrozenAttributes(unsigned attrs, + IntegrityLevel level) { + // Make all attributes permanent; if freezing, make data attributes + // read-only. + if (level == IntegrityLevel::Frozen && + !(attrs & (JSPROP_GETTER | JSPROP_SETTER))) { + return JSPROP_PERMANENT | JSPROP_READONLY; + } + return JSPROP_PERMANENT; +} + +/* 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->isNative() && !obj->as<NativeObject>().inDictionaryMode() && + !obj->is<TypedArrayObject>() && !obj->is<MappedArgumentsObject>()) { + HandleNativeObject nobj = obj.as<NativeObject>(); + + // Seal/freeze non-dictionary objects by constructing a new shape + // hierarchy mirroring the original one, which can be shared if many + // objects with the same structure are sealed/frozen. If we use the + // generic path below then any non-empty object will be converted to + // dictionary mode. + RootedShape last( + cx, EmptyShape::getInitialShape( + cx, nobj->getClass(), nobj->taggedProto(), + nobj->numFixedSlots(), nobj->lastProperty()->getObjectFlags())); + if (!last) { + return false; + } + + // Get an in-order list of the shapes in this object. + using ShapeVec = GCVector<Shape*, 8>; + Rooted<ShapeVec> shapes(cx, ShapeVec(cx)); + for (Shape::Range<NoGC> r(nobj->lastProperty()); !r.empty(); r.popFront()) { + if (!shapes.append(&r.front())) { + return false; + } + } + std::reverse(shapes.begin(), shapes.end()); + + for (Shape* shape : shapes) { + Rooted<StackShape> child(cx, StackShape(shape)); + bool isPrivate = JSID_IS_SYMBOL(child.get().propid) && + JSID_TO_SYMBOL(child.get().propid)->isPrivateName(); + // Private fields are not visible to SetIntegrity. + if (!isPrivate) { + child.setAttrs(child.attrs() | + GetSealedOrFrozenAttributes(child.attrs(), level)); + } + + last = cx->zone()->propertyTree().getChild(cx, last, child); + if (!last) { + return false; + } + } + + MOZ_ASSERT(nobj->lastProperty()->slotSpan() == last->slotSpan()); + MOZ_ALWAYS_TRUE(nobj->setLastProperty(cx, last)); + + // 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); + + const unsigned AllowConfigure = + JSPROP_IGNORE_ENUMERATE | JSPROP_IGNORE_READONLY | JSPROP_IGNORE_VALUE; + const unsigned AllowConfigureAndWritable = + AllowConfigure & ~JSPROP_IGNORE_READONLY; + + // 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.setAttributes(AllowConfigure | JSPROP_PERMANENT); + } else { + // 9.a.i-ii. + Rooted<PropertyDescriptor> currentDesc(cx); + if (!GetOwnPropertyDescriptor(cx, obj, id, ¤tDesc)) { + return false; + } + + // 9.a.iii. + if (!currentDesc.object()) { + continue; + } + + // 9.a.iii.1-2 + if (currentDesc.isAccessorDescriptor()) { + desc.setAttributes(AllowConfigure | JSPROP_PERMANENT); + } else { + desc.setAttributes(AllowConfigureAndWritable | JSPROP_PERMANENT | + JSPROP_READONLY); + } + } + + // 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->isNative()) { + if (!ObjectElements::FreezeOrSeal(cx, obj.as<NativeObject>(), level)) { + return false; + } + } + + return true; +} + +static bool ResolveLazyProperties(JSContext* cx, HandleNativeObject 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->isNative()) { + HandleNativeObject 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().get() > 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 (Shape::Range<NoGC> r(nobj->lastProperty()); !r.empty(); r.popFront()) { + Shape* shape = &r.front(); + + // Steps 9.c.i-ii. + if (shape->configurable() || + (level == IntegrityLevel::Frozen && shape->isDataDescriptor() && + shape->writable())) { + *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<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.object()) { + continue; + } + + // Steps 9.c.i-ii. + if (desc.configurable() || (level == IntegrityLevel::Frozen && + desc.isDataDescriptor() && desc.writable())) { + *result = false; + return true; + } + } + } + + // Step 10. + *result = true; + return true; +} + +/* * */ + +static inline JSObject* NewObject(JSContext* cx, HandleObjectGroup group, + gc::AllocKind kind, NewObjectKind newKind, + uint32_t initialShapeFlags = 0) { + const JSClass* clasp = group->clasp(); + + MOZ_ASSERT(clasp != &ArrayObject::class_); + MOZ_ASSERT_IF(clasp == &JSFunction::class_, + kind == gc::AllocKind::FUNCTION || + kind == gc::AllocKind::FUNCTION_EXTENDED); + + // For objects which can have fixed data following the object, only use + // enough fixed slots to cover the number of reserved slots in the object, + // regardless of the allocation kind specified. + size_t nfixed = ClassCanHaveFixedData(clasp) + ? GetGCKindSlots(gc::GetGCObjectKind(clasp), clasp) + : GetGCKindSlots(kind, clasp); + + RootedShape shape(cx, EmptyShape::getInitialShape(cx, clasp, group->proto(), + nfixed, initialShapeFlags)); + if (!shape) { + return nullptr; + } + + gc::InitialHeap heap = GetInitialHeap(newKind, group); + + JSObject* obj; + if (clasp->isJSFunction()) { + JS_TRY_VAR_OR_RETURN_NULL(cx, obj, + JSFunction::create(cx, kind, heap, shape, group)); + } else if (MOZ_LIKELY(clasp->isNative())) { + JS_TRY_VAR_OR_RETURN_NULL( + cx, obj, NativeObject::create(cx, kind, heap, shape, group)); + } else { + MOZ_ASSERT(IsTypedObjectClass(clasp)); + JS_TRY_VAR_OR_RETURN_NULL( + cx, obj, TypedObject::create(cx, kind, heap, shape, group)); + } + + probes::CreateObject(cx, obj); + return obj; +} + +void NewObjectCache::fillProto(EntryIndex entry, const JSClass* clasp, + js::TaggedProto proto, gc::AllocKind kind, + NativeObject* obj) { + MOZ_ASSERT_IF(proto.isObject(), !proto.toObject()->is<GlobalObject>()); + MOZ_ASSERT(obj->taggedProto() == proto); + return fill(entry, clasp, proto.raw(), kind, obj); +} + +bool js::NewObjectWithTaggedProtoIsCachable(JSContext* cx, + Handle<TaggedProto> proto, + NewObjectKind newKind, + const JSClass* clasp) { + return !cx->isHelperThreadContext() && proto.isObject() && + newKind == GenericObject && clasp->isNative() && + !proto.toObject()->is<GlobalObject>(); +} + +JSObject* js::NewObjectWithGivenTaggedProto(JSContext* cx, const JSClass* clasp, + Handle<TaggedProto> proto, + gc::AllocKind allocKind, + NewObjectKind newKind, + uint32_t initialShapeFlags) { + if (CanChangeToBackgroundAllocKind(allocKind, clasp)) { + allocKind = ForegroundToBackgroundAllocKind(allocKind); + } + + bool isCachable = + NewObjectWithTaggedProtoIsCachable(cx, proto, newKind, clasp); + if (isCachable) { + NewObjectCache& cache = cx->caches().newObjectCache; + NewObjectCache::EntryIndex entry = -1; + if (cache.lookupProto(clasp, proto.toObject(), allocKind, &entry)) { + JSObject* obj = + cache.newObjectFromHit(cx, entry, GetInitialHeap(newKind, clasp)); + if (obj) { + return obj; + } + } + } + + RootedObjectGroup group(cx, ObjectGroup::defaultNewGroup(cx, clasp, proto)); + if (!group) { + return nullptr; + } + + RootedObject obj(cx, + NewObject(cx, group, allocKind, newKind, initialShapeFlags)); + if (!obj) { + return nullptr; + } + + if (isCachable && !obj->as<NativeObject>().hasDynamicSlots()) { + NewObjectCache& cache = cx->caches().newObjectCache; + NewObjectCache::EntryIndex entry = -1; + cache.lookupProto(clasp, proto.toObject(), allocKind, &entry); + cache.fillProto(entry, clasp, proto, allocKind, &obj->as<NativeObject>()); + } + + return obj; +} + +static bool NewObjectIsCachable(JSContext* cx, NewObjectKind newKind, + const JSClass* clasp) { + return !cx->isHelperThreadContext() && newKind == GenericObject && + clasp->isNative(); +} + +JSObject* js::NewObjectWithClassProto(JSContext* cx, const JSClass* clasp, + HandleObject protoArg, + gc::AllocKind allocKind, + NewObjectKind newKind) { + if (protoArg) { + return NewObjectWithGivenTaggedProto(cx, clasp, AsTaggedProto(protoArg), + allocKind, newKind); + } + + if (CanChangeToBackgroundAllocKind(allocKind, clasp)) { + allocKind = ForegroundToBackgroundAllocKind(allocKind); + } + + Handle<GlobalObject*> global = cx->global(); + + bool isCachable = NewObjectIsCachable(cx, newKind, clasp); + if (isCachable) { + NewObjectCache& cache = cx->caches().newObjectCache; + NewObjectCache::EntryIndex entry = -1; + if (cache.lookupGlobal(clasp, global, allocKind, &entry)) { + gc::InitialHeap heap = GetInitialHeap(newKind, clasp); + JSObject* obj = cache.newObjectFromHit(cx, entry, heap); + if (obj) { + return obj; + } + } + } + + // 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; + } + + RootedObjectGroup group( + cx, ObjectGroup::defaultNewGroup(cx, clasp, TaggedProto(proto))); + if (!group) { + return nullptr; + } + + JSObject* obj = NewObject(cx, group, allocKind, newKind); + if (!obj) { + return nullptr; + } + + if (isCachable && !obj->as<NativeObject>().hasDynamicSlots()) { + NewObjectCache& cache = cx->caches().newObjectCache; + NewObjectCache::EntryIndex entry = -1; + cache.lookupGlobal(clasp, global, allocKind, &entry); + cache.fillGlobal(entry, clasp, global, allocKind, &obj->as<NativeObject>()); + } + + return obj; +} + +static bool NewObjectWithGroupIsCachable(JSContext* cx, HandleObjectGroup group, + NewObjectKind newKind) { + if (!group->proto().isObject() || newKind != GenericObject || + !group->clasp()->isNative() || cx->isHelperThreadContext()) { + return false; + } + + return true; +} + +/* + * Create a plain object with the specified group. This bypasses getNewGroup to + * avoid losing creation site information for objects made by scripted 'new'. + */ +JSObject* js::NewObjectWithGroupCommon(JSContext* cx, HandleObjectGroup group, + gc::AllocKind allocKind, + NewObjectKind newKind) { + MOZ_ASSERT(gc::IsObjectAllocKind(allocKind)); + if (CanChangeToBackgroundAllocKind(allocKind, group->clasp())) { + allocKind = ForegroundToBackgroundAllocKind(allocKind); + } + + bool isCachable = NewObjectWithGroupIsCachable(cx, group, newKind); + if (isCachable) { + NewObjectCache& cache = cx->caches().newObjectCache; + NewObjectCache::EntryIndex entry = -1; + if (cache.lookupGroup(group, allocKind, &entry)) { + JSObject* obj = + cache.newObjectFromHit(cx, entry, GetInitialHeap(newKind, group)); + if (obj) { + return obj; + } + } + } + + JSObject* obj = NewObject(cx, group, allocKind, newKind); + if (!obj) { + return nullptr; + } + + if (isCachable && !obj->as<NativeObject>().hasDynamicSlots()) { + NewObjectCache& cache = cx->caches().newObjectCache; + NewObjectCache::EntryIndex entry = -1; + cache.lookupGroup(group, allocKind, &entry); + cache.fillGroup(entry, group, allocKind, &obj->as<NativeObject>()); + } + + return obj; +} + +bool js::NewObjectScriptedCall(JSContext* cx, MutableHandleObject pobj) { + gc::AllocKind allocKind = NewObjectGCKind(&PlainObject::class_); + NewObjectKind newKind = GenericObject; + + JSObject* obj = NewBuiltinClassInstance<PlainObject>(cx, allocKind, newKind); + if (!obj) { + return false; + } + + pobj.set(obj); + return true; +} + +JSObject* js::CreateThis(JSContext* cx, const JSClass* newclasp, + HandleObject callee) { + RootedObject proto(cx); + if (!GetPrototypeFromConstructor( + cx, callee, JSCLASS_CACHED_PROTO_KEY(newclasp), &proto)) { + return nullptr; + } + gc::AllocKind kind = NewObjectGCKind(newclasp); + return NewObjectWithClassProto(cx, newclasp, proto, kind); +} + +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. + { + mozilla::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<PropertyDescriptor> desc(cx); + + if (!GetOwnPropertyDescriptor(cx, obj, id, &desc)) { + return false; + } + MOZ_ASSERT(desc.object()); + + // Silently skip JSGetterOp/JSSetterOp-implemented accessors. + if (desc.getter() && !desc.hasGetterObject()) { + return true; + } + if (desc.setter() && !desc.hasSetterObject()) { + return true; + } + + JSAutoRealm ar(cx, target); + cx->markId(id); + RootedId wrappedId(cx, id); + if (!cx->compartment()->wrap(cx, &desc)) { + return false; + } + + return DefineProperty(cx, target, wrappedId, desc); +} + +JS_FRIEND_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 GetScriptArrayObjectElements( + HandleArrayObject arr, MutableHandle<GCVector<Value>> values) { + MOZ_ASSERT(!arr->isIndexed()); + + size_t length = arr->length(); + if (!values.appendN(MagicValue(JS_ELEMENTS_HOLE), length)) { + return false; + } + + size_t initlen = arr->getDenseInitializedLength(); + for (size_t i = 0; i < initlen; i++) { + values[i].set(arr->getDenseElement(i)); + } + + return true; +} + +static bool GetScriptPlainObjectProperties( + HandleObject obj, MutableHandle<IdValueVector> properties) { + MOZ_ASSERT(obj->is<PlainObject>()); + PlainObject* nobj = &obj->as<PlainObject>(); + + if (!properties.appendN(IdValuePair(), nobj->slotSpan())) { + return false; + } + + for (Shape::Range<NoGC> r(nobj->lastProperty()); !r.empty(); r.popFront()) { + Shape& shape = r.front(); + MOZ_ASSERT(shape.isDataDescriptor()); + uint32_t slot = shape.slot(); + properties[slot].get().id = shape.propid(); + properties[slot].get().value = nobj->getSlot(slot); + } + + for (size_t i = 0; i < nobj->getDenseInitializedLength(); i++) { + Value v = nobj->getDenseElement(i); + if (!v.isMagic(JS_ELEMENTS_HOLE) && + !properties.emplaceBack(INT_TO_JSID(i), v)) { + return false; + } + } + + return true; +} + +static bool DeepCloneValue(JSContext* cx, Value* vp) { + if (vp->isObject()) { + RootedObject obj(cx, &vp->toObject()); + obj = DeepCloneObjectLiteral(cx, obj); + if (!obj) { + return false; + } + vp->setObject(*obj); + } else { + cx->markAtomValue(*vp); + } + return true; +} + +JSObject* js::DeepCloneObjectLiteral(JSContext* cx, HandleObject obj) { + /* NB: Keep this in sync with XDRObjectLiteral. */ + MOZ_ASSERT(obj->is<PlainObject>() || obj->is<ArrayObject>()); + + if (obj->is<ArrayObject>()) { + Rooted<GCVector<Value>> values(cx, GCVector<Value>(cx)); + if (!GetScriptArrayObjectElements(obj.as<ArrayObject>(), &values)) { + return nullptr; + } + + // Deep clone any elements. + for (uint32_t i = 0; i < values.length(); ++i) { + if (!DeepCloneValue(cx, values[i].address())) { + return nullptr; + } + } + + return NewDenseCopiedArray(cx, values.length(), values.begin(), + /* proto = */ nullptr, TenuredObject); + } + + Rooted<IdValueVector> properties(cx, IdValueVector(cx)); + if (!GetScriptPlainObjectProperties(obj, &properties)) { + return nullptr; + } + + for (size_t i = 0; i < properties.length(); i++) { + cx->markId(properties[i].get().id); + if (!DeepCloneValue(cx, &properties[i].get().value)) { + return nullptr; + } + } + + return NewPlainObjectWithProperties(cx, properties.begin(), + properties.length(), TenuredObject); +} + +static bool InitializePropertiesFromCompatibleNativeObject( + JSContext* cx, HandleNativeObject dst, HandleNativeObject src) { + cx->check(src, dst); + MOZ_ASSERT(src->getClass() == dst->getClass()); + MOZ_ASSERT(dst->lastProperty()->getObjectFlags() == 0); + MOZ_ASSERT(src->numFixedSlots() == dst->numFixedSlots()); + + 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)); + } + + MOZ_ASSERT(!src->hasPrivate()); + RootedShape shape(cx); + if (src->staticPrototype() == dst->staticPrototype()) { + shape = src->lastProperty(); + } 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 0. + shape = EmptyShape::getInitialShape(cx, dst->getClass(), dst->taggedProto(), + dst->numFixedSlots(), 0); + if (!shape) { + return false; + } + + // Get an in-order list of the shapes in the src object. + Rooted<ShapeVector> shapes(cx, ShapeVector(cx)); + for (Shape::Range<NoGC> r(src->lastProperty()); !r.empty(); r.popFront()) { + if (!shapes.append(&r.front())) { + return false; + } + } + std::reverse(shapes.begin(), shapes.end()); + + for (Shape* shapeToClone : shapes) { + Rooted<StackShape> child(cx, StackShape(shapeToClone)); + shape = cx->zone()->propertyTree().getChild(cx, shape, child); + if (!shape) { + return false; + } + } + } + size_t span = shape->slotSpan(); + if (!dst->setLastProperty(cx, shape)) { + return false; + } + for (size_t i = JSCLASS_RESERVED_SLOTS(src->getClass()); i < span; i++) { + dst->setSlot(i, src->getSlot(i)); + } + + return true; +} + +JS_FRIEND_API bool JS_InitializePropertiesFromCompatibleNativeObject( + JSContext* cx, HandleObject dst, HandleObject src) { + return InitializePropertiesFromCompatibleNativeObject( + cx, dst.as<NativeObject>(), src.as<NativeObject>()); +} + +template <XDRMode mode> +XDRResult js::XDRObjectLiteral(XDRState<mode>* xdr, MutableHandleObject obj) { + /* NB: Keep this in sync with DeepCloneObjectLiteral. */ + + JSContext* cx = xdr->cx(); + cx->check(obj); + + // Distinguish between objects and array classes. + uint32_t isArray = 0; + { + if (mode == XDR_ENCODE) { + MOZ_ASSERT(obj->is<PlainObject>() || obj->is<ArrayObject>()); + isArray = obj->is<ArrayObject>() ? 1 : 0; + } + + MOZ_TRY(xdr->codeUint32(&isArray)); + } + + RootedValue tmpValue(cx), tmpIdValue(cx); + RootedId tmpId(cx); + + if (isArray) { + Rooted<GCVector<Value>> values(cx, GCVector<Value>(cx)); + if (mode == XDR_ENCODE) { + RootedArrayObject arr(cx, &obj->as<ArrayObject>()); + if (!GetScriptArrayObjectElements(arr, &values)) { + return xdr->fail(JS::TranscodeResult_Throw); + } + } + + uint32_t initialized; + if (mode == XDR_ENCODE) { + initialized = values.length(); + } + MOZ_TRY(xdr->codeUint32(&initialized)); + if (mode == XDR_DECODE && + !values.appendN(MagicValue(JS_ELEMENTS_HOLE), initialized)) { + return xdr->fail(JS::TranscodeResult_Throw); + } + + // Recursively copy dense elements. + for (unsigned i = 0; i < initialized; i++) { + MOZ_TRY(XDRScriptConst(xdr, values[i])); + } + + if (mode == XDR_DECODE) { + obj.set(NewDenseCopiedArray(cx, values.length(), values.begin(), + /* proto = */ nullptr, TenuredObject)); + if (!obj) { + return xdr->fail(JS::TranscodeResult_Throw); + } + } + + return Ok(); + } + + // Code the properties in the object. + Rooted<IdValueVector> properties(cx, IdValueVector(cx)); + if (mode == XDR_ENCODE && !GetScriptPlainObjectProperties(obj, &properties)) { + return xdr->fail(JS::TranscodeResult_Throw); + } + + uint32_t nproperties = properties.length(); + MOZ_TRY(xdr->codeUint32(&nproperties)); + + if (mode == XDR_DECODE && !properties.appendN(IdValuePair(), nproperties)) { + return xdr->fail(JS::TranscodeResult_Throw); + } + + for (size_t i = 0; i < nproperties; i++) { + if (mode == XDR_ENCODE) { + tmpIdValue = IdToValue(properties[i].get().id); + tmpValue = properties[i].get().value; + } + + MOZ_TRY(XDRScriptConst(xdr, &tmpIdValue)); + MOZ_TRY(XDRScriptConst(xdr, &tmpValue)); + + if (mode == XDR_DECODE) { + if (!PrimitiveValueToId<CanGC>(cx, tmpIdValue, &tmpId)) { + return xdr->fail(JS::TranscodeResult_Throw); + } + properties[i].get().id = tmpId; + properties[i].get().value = tmpValue; + } + } + + if (mode == XDR_DECODE) { + obj.set(NewPlainObjectWithProperties(cx, properties.begin(), + properties.length(), TenuredObject)); + if (!obj) { + return xdr->fail(JS::TranscodeResult_Throw); + } + } + + return Ok(); +} + +template XDRResult js::XDRObjectLiteral(XDRState<XDR_ENCODE>* xdr, + MutableHandleObject obj); + +template XDRResult js::XDRObjectLiteral(XDRState<XDR_DECODE>* xdr, + MutableHandleObject obj); + +/* static */ +bool NativeObject::fillInAfterSwap(JSContext* cx, HandleNativeObject obj, + NativeObject* old, HandleValueVector values, + void* priv) { + // 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(obj->slotSpan() == values.length()); + MOZ_ASSERT(!IsInsideNursery(obj)); + + // Make sure the shape's numFixedSlots() is correct. + size_t nfixed = + gc::GetGCKindSlots(obj->asTenured().getAllocKind(), obj->getClass()); + if (nfixed != obj->shape()->numFixedSlots()) { + if (!NativeObject::generateOwnShape(cx, obj)) { + return false; + } + obj->shape()->setNumFixedSlots(nfixed); + } + + if (obj->hasPrivate()) { + obj->setPrivate(priv); + } else { + MOZ_ASSERT(!priv); + } + + uint32_t oldDictionarySlotSpan = + obj->inDictionaryMode() ? obj->dictionaryModeSlotSpan() : 0; + + Zone* zone = obj->zone(); + if (obj->hasDynamicSlots()) { + ObjectSlots* slotsHeader = obj->getSlotsHeader(); + size_t size = ObjectSlots::allocSize(slotsHeader->capacity()); + zone->removeCellMemory(old, size, MemoryUse::ObjectSlots); + js_free(slotsHeader); + obj->setEmptyDynamicSlots(0); + } + + size_t ndynamic = + calculateDynamicSlots(nfixed, values.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); + } + + obj->initSlots(values.begin(), values.length()); + + return true; +} + +void JSObject::fixDictionaryShapeAfterSwap() { + // Dictionary shapes can point back to their containing objects, so after + // swapping the guts of those objects fix the pointers up. + if (isNative() && as<NativeObject>().inDictionaryMode()) { + shape()->dictNext.setObject(this); + } +} + +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->isProxy() || clasp->isDOMClass(); +} + +static MOZ_MUST_USE bool CopyProxyValuesBeforeSwap( + JSContext* cx, ProxyObject* proxy, MutableHandleValueVector values) { + MOZ_ASSERT(values.empty()); + + // Remove the GCPtrValues 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 (!values.reserve(2 + proxy->numReservedSlots())) { + return false; + } + + js::detail::ProxyValueArray* valArray = + js::detail::GetProxyDataLayout(proxy)->values(); + sb.unputValue(&valArray->expandoSlot); + sb.unputValue(&valArray->privateSlot); + values.infallibleAppend(valArray->expandoSlot); + values.infallibleAppend(valArray->privateSlot); + + for (size_t i = 0; i < proxy->numReservedSlots(); i++) { + sb.unputValue(&valArray->reservedSlots.slots[i]); + values.infallibleAppend(valArray->reservedSlots.slots[i]); + } + + return true; +} + +bool ProxyObject::initExternalValueArrayAfterSwap( + JSContext* cx, const HandleValueVector values) { + MOZ_ASSERT(getClass()->isProxy()); + + size_t nreserved = numReservedSlots(); + + // |values| contains the expando slot, private slot and the reserved slots. + MOZ_ASSERT(values.length() == 2 + nreserved); + + size_t nbytes = js::detail::ProxyValueArray::sizeOf(nreserved); + + auto* valArray = reinterpret_cast<js::detail::ProxyValueArray*>( + cx->zone()->pod_malloc<uint8_t>(nbytes)); + if (!valArray) { + return false; + } + + valArray->expandoSlot = values[0]; + valArray->privateSlot = values[1]; + + for (size_t i = 0; i < nreserved; i++) { + valArray->reservedSlots.slots[i] = values[i + 2]; + } + + // Note: we allocate external slots iff the proxy had an inline + // ProxyValueArray, so at this point reservedSlots points into the + // old object and we don't have to free anything. + data.reservedSlots = &valArray->reservedSlots; + return true; +} + +/* 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 not be run. + MOZ_ASSERT(IsBackgroundFinalized(a->asTenured().getAllocKind()) == + IsBackgroundFinalized(b->asTenured().getAllocKind())); + 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. + MOZ_RELEASE_ASSERT(js::ObjectMayBeSwapped(a)); + MOZ_RELEASE_ASSERT(js::ObjectMayBeSwapped(b)); + + /* + * Neither object may be in the nursery, but ensure we update any embedded + * nursery pointers in either object. + */ + MOZ_ASSERT(!IsInsideNursery(a) && !IsInsideNursery(b)); + gc::StoreBuffer& storeBuffer = cx->runtime()->gc.storeBuffer(); + storeBuffer.putWholeCell(a); + storeBuffer.putWholeCell(b); + if (a->zone()->wasGCStarted() || b->zone()->wasGCStarted()) { + storeBuffer.setMayHavePointersToDeadCells(); + } + + unsigned r = NotifyGCPreSwap(a, b); + + // Do the fundamental swapping of the contents of two objects. + MOZ_ASSERT(a->compartment() == b->compartment()); + MOZ_ASSERT(a->is<JSFunction>() == b->is<JSFunction>()); + + // Don't try to swap functions with different sizes. + MOZ_ASSERT_IF(a->is<JSFunction>(), + a->tenuredSizeOfThis() == b->tenuredSizeOfThis()); + + // Watch for oddball objects that have special organizational issues and + // can't be swapped. + MOZ_ASSERT(!a->is<RegExpObject>() && !b->is<RegExpObject>()); + MOZ_ASSERT(!a->is<ArrayObject>() && !b->is<ArrayObject>()); + MOZ_ASSERT(!a->is<ArrayBufferObject>() && !b->is<ArrayBufferObject>()); + MOZ_ASSERT(!a->is<TypedArrayObject>() && !b->is<TypedArrayObject>()); + MOZ_ASSERT(!a->is<TypedObject>() && !b->is<TypedObject>()); + + // Don't swap objects that may currently be participating in shape + // teleporting optimizations. + // + // See: ReshapeForProtoMutation, ReshapeForShadowedProp + MOZ_ASSERT_IF(a->isNative() && a->isDelegate(), + a->taggedProto() == TaggedProto()); + MOZ_ASSERT_IF(b->isNative() && b->isDelegate(), + b->taggedProto() == TaggedProto()); + + bool aIsProxyWithInlineValues = + a->is<ProxyObject>() && a->as<ProxyObject>().usingInlineValueArray(); + bool bIsProxyWithInlineValues = + b->is<ProxyObject>() && b->as<ProxyObject>().usingInlineValueArray(); + + // Swap element associations. + Zone* zone = a->zone(); + zone->swapCellMemory(a, b, MemoryUse::ObjectElements); + + if (a->tenuredSizeOfThis() == b->tenuredSizeOfThis()) { + // When both objects are the same size, just do a plain swap of their + // contents. + + // Swap slot associations. + zone->swapCellMemory(a, b, MemoryUse::ObjectSlots); + + size_t size = a->tenuredSizeOfThis(); + + char tmp[mozilla::tl::Max<sizeof(JSFunction), + sizeof(JSObject_Slots16)>::value]; + MOZ_ASSERT(size <= sizeof(tmp)); + + js_memcpy(tmp, a, size); + js_memcpy(a, b, size); + js_memcpy(b, tmp, size); + + a->fixDictionaryShapeAfterSwap(); + b->fixDictionaryShapeAfterSwap(); + + if (aIsProxyWithInlineValues) { + b->as<ProxyObject>().setInlineValueArray(); + } + if (bIsProxyWithInlineValues) { + a->as<ProxyObject>().setInlineValueArray(); + } + } else { + // Avoid GC in here to avoid confusing the tracing code with our + // intermediate state. + gc::AutoSuppressGC suppress(cx); + + // 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. + NativeObject* na = a->isNative() ? &a->as<NativeObject>() : nullptr; + NativeObject* nb = b->isNative() ? &b->as<NativeObject>() : nullptr; + + // Remember the original values from the objects. + RootedValueVector avals(cx); + void* apriv = nullptr; + if (na) { + apriv = na->hasPrivate() ? na->getPrivate() : nullptr; + for (size_t i = 0; i < na->slotSpan(); i++) { + if (!avals.append(na->getSlot(i))) { + oomUnsafe.crash("JSObject::swap"); + } + } + } + RootedValueVector bvals(cx); + void* bpriv = nullptr; + if (nb) { + bpriv = nb->hasPrivate() ? nb->getPrivate() : nullptr; + for (size_t i = 0; i < nb->slotSpan(); i++) { + if (!bvals.append(nb->getSlot(i))) { + oomUnsafe.crash("JSObject::swap"); + } + } + } + + // Do the same for proxies storing ProxyValueArray inline. + ProxyObject* proxyA = + a->is<ProxyObject>() ? &a->as<ProxyObject>() : nullptr; + ProxyObject* proxyB = + b->is<ProxyObject>() ? &b->as<ProxyObject>() : nullptr; + + if (aIsProxyWithInlineValues) { + if (!CopyProxyValuesBeforeSwap(cx, proxyA, &avals)) { + oomUnsafe.crash("CopyProxyValuesBeforeSwap"); + } + } + if (bIsProxyWithInlineValues) { + if (!CopyProxyValuesBeforeSwap(cx, proxyB, &bvals)) { + oomUnsafe.crash("CopyProxyValuesBeforeSwap"); + } + } + + // 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); + + a->fixDictionaryShapeAfterSwap(); + b->fixDictionaryShapeAfterSwap(); + + if (na) { + if (!NativeObject::fillInAfterSwap(cx, b.as<NativeObject>(), na, avals, + apriv)) { + oomUnsafe.crash("fillInAfterSwap"); + } + } + if (nb) { + if (!NativeObject::fillInAfterSwap(cx, a.as<NativeObject>(), nb, bvals, + bpriv)) { + oomUnsafe.crash("fillInAfterSwap"); + } + } + if (aIsProxyWithInlineValues) { + if (!b->as<ProxyObject>().initExternalValueArrayAfterSwap(cx, avals)) { + oomUnsafe.crash("initExternalValueArray"); + } + } + if (bIsProxyWithInlineValues) { + if (!a->as<ProxyObject>().initExternalValueArrayAfterSwap(cx, bvals)) { + oomUnsafe.crash("initExternalValueArray"); + } + } + } + + /* + * 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. + */ + if (zone->needsIncrementalBarrier()) { + a->traceChildren(zone->barrierTracer()); + b->traceChildren(zone->barrierTracer()); + } + + NotifyGCPostSwap(a, b, r); +} + +static NativeObject* DefineConstructorAndPrototype( + JSContext* cx, HandleObject obj, HandleAtom 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. + RootedNativeObject proto( + cx, GlobalObject::createBlankPrototypeInheriting(cx, clasp, protoProto)); + if (!proto) { + return nullptr; + } + + RootedNativeObject 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; + } + + 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, + 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) { + RootedAtom atom(cx, Atomize(cx, clasp->name, strlen(clasp->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 null, default to Object.prototype. + */ + RootedObject protoProto(cx, protoProto_); + if (!protoProto) { + protoProto = GlobalObject::getOrCreateObjectPrototype(cx, cx->global()); + if (!protoProto) { + return nullptr; + } + } + + return DefineConstructorAndPrototype(cx, obj, atom, protoProto, clasp, + constructor, nargs, ps, fs, static_ps, + static_fs, ctorp); +} + +void JSObject::fixupAfterMovingGC() { + if (IsForwarded(group())) { + setGroupRaw(Forwarded(group())); + } +} + +static bool ReshapeForProtoMutation(JSContext* cx, HandleObject obj) { + // To avoid the JIT guarding on each prototype in chain to detect prototype + // mutation, we can instead reshape the rest of the proto chain such that a + // guard on any of them is sufficient. To avoid excessive reshaping and + // invalidation, we apply heuristics to decide when to apply this and when + // to require a guard. + // + // Heuristics: + // - Set UNCACHEABLE_PROTO flag on shape to avoid creating too many private + // shape copies. + // - Only propegate along proto chain if we are mark DELEGATE. This avoids + // reshaping in normal object access cases. + // + // NOTE: We only handle NativeObjects and don't propegate reshapes through + // any non-native objects on the chain. + // + // See Also: + // - GeneratePrototypeGuards + // - GeneratePrototypeHoleGuards + // - ObjectGroup::defaultNewGroup + + RootedObject pobj(cx, obj); + + while (pobj && pobj->isNative()) { + if (!JSObject::setUncacheableProto(cx, pobj)) { + return false; + } + + if (!obj->isDelegate()) { + break; + } + + pobj = pobj->staticPrototype(); + } + + return true; +} + +static bool SetProto(JSContext* cx, HandleObject obj, + Handle<js::TaggedProto> proto) { + // Regenerate object shape (and possibly prototype shape) to invalidate JIT + // code that is affected by a prototype mutation. + if (!ReshapeForProtoMutation(cx, obj)) { + return false; + } + + if (proto.isObject()) { + RootedObject protoObj(cx, proto.toObject()); + if (!JSObject::setDelegate(cx, protoObj)) { + return false; + } + } + + RootedObjectGroup oldGroup(cx, obj->group()); + + ObjectGroup* newGroup; + { + AutoRealm ar(cx, oldGroup); + newGroup = ObjectGroup::defaultNewGroup(cx, obj->getClass(), proto); + if (!newGroup) { + return false; + } + } + + obj->setGroup(newGroup); + return true; +} + +/** + * 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::GetObjectFromIncumbentGlobal(JSContext* cx, MutableHandleObject obj) { + Rooted<GlobalObject*> globalObj(cx, cx->runtime()->getIncumbentGlobal(cx)); + if (!globalObj) { + obj.set(nullptr); + return true; + } + + { + AutoRealm ar(cx, globalObj); + obj.set(GlobalObject::getOrCreateObjectPrototype(cx, globalObj)); + if (!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) { + Value v = obj->nonCCWGlobal().getPrototype(key); + return v.isObject() && obj == &v.toObject(); +} + +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; + } + + GlobalObject& global = obj->as<JSFunction>().global(); + for (size_t k = 0; k < JSProto_LIMIT; ++k) { + JSProtoKey key = static_cast<JSProtoKey>(k); + if (global.getConstructor(key) == ObjectValue(*obj)) { + return key; + } + } + + return JSProto_Null; +} + +bool js::LookupProperty(JSContext* cx, HandleObject obj, js::HandleId id, + MutableHandleObject objp, + MutableHandle<PropertyResult> propp) { + if (LookupPropertyOp op = obj->getOpsLookupProperty()) { + return op(cx, obj, id, objp, propp); + } + return LookupPropertyInline<CanGC>(cx, obj.as<NativeObject>(), id, objp, + propp); +} + +bool js::LookupName(JSContext* cx, HandlePropertyName name, + HandleObject envChain, MutableHandleObject objp, + MutableHandleObject pobjp, + MutableHandle<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) { + objp.set(env); + return true; + } + } + + objp.set(nullptr); + pobjp.set(nullptr); + propp.setNotFound(); + return true; +} + +bool js::LookupNameNoGC(JSContext* cx, PropertyName* name, JSObject* envChain, + JSObject** objp, JSObject** pobjp, + PropertyResult* propp) { + AutoAssertNoPendingException nogc(cx); + + MOZ_ASSERT(!*objp && !*pobjp && !*propp); + + for (JSObject* env = envChain; env; env = env->enclosingEnvironment()) { + if (env->getOpsLookupProperty()) { + return false; + } + if (!LookupPropertyInline<NoGC>(cx, &env->as<NativeObject>(), + NameToId(name), pobjp, propp)) { + return false; + } + if (*propp) { + *objp = env; + return true; + } + } + + return true; +} + +bool js::LookupNameWithGlobalDefault(JSContext* cx, HandlePropertyName name, + HandleObject envChain, + MutableHandleObject objp) { + RootedId id(cx, NameToId(name)); + + RootedObject pobj(cx); + Rooted<PropertyResult> prop(cx); + + RootedObject env(cx, envChain); + for (; !env->is<GlobalObject>(); env = env->enclosingEnvironment()) { + if (!LookupProperty(cx, env, id, &pobj, &prop)) { + return false; + } + if (prop) { + break; + } + } + + objp.set(env); + return true; +} + +bool js::LookupNameUnqualified(JSContext* cx, HandlePropertyName name, + HandleObject envChain, + MutableHandleObject objp) { + RootedId id(cx, NameToId(name)); + + RootedObject pobj(cx); + Rooted<PropertyResult> prop(cx); + + RootedObject env(cx, envChain); + for (; !env->isUnqualifiedVarObj(); env = env->enclosingEnvironment()) { + if (!LookupProperty(cx, env, id, &pobj, &prop)) { + return false; + } + if (prop) { + break; + } + } + + // See note above RuntimeLexicalErrorObject. + if (pobj == env) { + bool isTDZ = false; + if (prop && name != cx->names().dotThis) { + // 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); + Rooted<DebugEnvironmentProxy*> envProxy( + cx, &env->as<DebugEnvironmentProxy>()); + if (!DebugEnvironmentProxy::getMaybeSentinelValue(cx, envProxy, id, + &v)) { + return false; + } + isTDZ = IsUninitializedLexical(v); + } else { + isTDZ = IsUninitializedLexicalSlot(env, prop); + } + } + + if (isTDZ) { + env = RuntimeLexicalErrorObject::create(cx, env, + JSMSG_UNINITIALIZED_LEXICAL); + if (!env) { + return false; + } + } else if (env->is<LexicalEnvironmentObject>() && + !prop.shape()->writable()) { + // Assigning to a named lambda callee name is a no-op in sloppy mode. + Rooted<LexicalEnvironmentObject*> lexicalEnv( + cx, &env->as<LexicalEnvironmentObject>()); + if (lexicalEnv->isExtensible() || + lexicalEnv->scope().kind() != ScopeKind::NamedLambda) { + MOZ_ASSERT(name != cx->names().dotThis); + env = + RuntimeLexicalErrorObject::create(cx, env, JSMSG_BAD_CONST_ASSIGN); + if (!env) { + return false; + } + } + } + } + + objp.set(env); + return true; +} + +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<PropertyDescriptor> desc(cx); + if (!op(cx, obj, id, &desc)) { + return false; + } + *result = !!desc.object(); + return true; + } + + Rooted<PropertyResult> prop(cx); + 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, + JSObject** objp, PropertyResult* propp) { + bool isTypedArrayOutOfRange = false; + do { + if (!LookupOwnPropertyPure(cx, obj, id, propp, &isTypedArrayOutOfRange)) { + return false; + } + + if (*propp) { + *objp = obj; + return true; + } + + if (isTypedArrayOutOfRange) { + *objp = nullptr; + return true; + } + + obj = obj->staticPrototype(); + } while (obj); + + *objp = nullptr; + propp->setNotFound(); + return true; +} + +bool js::LookupOwnPropertyPure(JSContext* cx, JSObject* obj, jsid id, + PropertyResult* propp, + bool* isTypedArrayOutOfRange /* = nullptr */) { + JS::AutoCheckCannotGC nogc; + if (isTypedArrayOutOfRange) { + *isTypedArrayOutOfRange = false; + } + + if (obj->isNative()) { + // Search for a native dense element, typed array element, or property. + + if (JSID_IS_INT(id)) { + uint32_t index = JSID_TO_INT(id); + if (obj->as<NativeObject>().containsDenseElement(index)) { + propp->setDenseElement(index); + return true; + } + } + + if (obj->is<TypedArrayObject>()) { + JS::Result<mozilla::Maybe<uint64_t>> index = IsTypedArrayIndex(cx, id); + if (index.isErr()) { + cx->recoverFromOutOfMemory(); + return false; + } + + if (index.inspect()) { + if (index.inspect().value() < + obj->as<TypedArrayObject>().length().get()) { + propp->setTypedArrayElement(index.inspect().value()); + } else { + propp->setNotFound(); + if (isTypedArrayOutOfRange) { + *isTypedArrayOutOfRange = true; + } + } + return true; + } + } + + if (Shape* shape = obj->as<NativeObject>().lookupPure(id)) { + propp->setNativeProperty(shape); + return true; + } + + // Fail if there's a resolve hook, unless the mayResolve hook tells + // us the resolve hook won't define a property with this id. + if (ClassMayResolveId(cx->names(), obj->getClass(), id, obj)) { + return false; + } + } else if (obj->is<TypedObject>()) { + if (obj->as<TypedObject>().typeDescr().hasProperty(cx, id)) { + propp->setNonNativeProperty(); + return true; + } + } else { + return false; + } + + propp->setNotFound(); + return true; +} + +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. + Shape* shape = prop.shape(); + if (!shape->isDataProperty()) { + return false; + } + + *vp = pobj->getSlot(shape->slot()); + MOZ_ASSERT(!vp->isMagic()); + return true; +} + +bool js::GetPropertyPure(JSContext* cx, JSObject* obj, jsid id, Value* vp) { + JSObject* pobj; + PropertyResult prop; + if (!LookupPropertyPure(cx, obj, id, &pobj, &prop)) { + return false; + } + + if (!prop) { + vp->setUndefined(); + return true; + } + + return pobj->isNative() && + NativeGetPureInline(&pobj->as<NativeObject>(), 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) { + *found = false; + vp->setUndefined(); + return true; + } + + *found = true; + return obj->isNative() && + NativeGetPureInline(&obj->as<NativeObject>(), id, prop, vp, cx); +} + +static inline bool NativeGetGetterPureInline(PropertyResult prop, + JSFunction** fp) { + MOZ_ASSERT(prop.isNativeProperty()); + + if (prop.shape()->hasGetterObject()) { + Shape* shape = prop.shape(); + if (shape->getterObject()->is<JSFunction>()) { + *fp = &shape->getterObject()->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. */ + JSObject* pobj; + PropertyResult prop; + if (!LookupPropertyPure(cx, obj, id, &pobj, &prop)) { + return false; + } + + if (!prop) { + *fp = nullptr; + return true; + } + + return prop.isNativeProperty() && NativeGetGetterPureInline(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) { + *fp = nullptr; + return true; + } + + return prop.isNativeProperty() && NativeGetGetterPureInline(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 || !prop.isNativeProperty() || !prop.shape()->hasGetterObject()) { + return true; + } + + JSObject* getterObj = prop.shape()->getterObject(); + if (!getterObj->is<JSFunction>()) { + return true; + } + + JSFunction* getter = &getterObj->as<JSFunction>(); + if (!getter->isNative()) { + 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 && prop.isNativeProperty() && prop.shape()->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 Typed Objects, per the spec. + */ + if (obj->is<TypedObject>()) { + JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, + JSMSG_CANT_SET_PROTO_OF, + "incompatible TypedObject"); + return false; + } + + /* 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); + } + + // If this is a global object, resolve the Object class so that its + // [[Prototype]] chain is always properly immutable, even in the presence + // of lazy standard classes. + if (obj->is<GlobalObject>()) { + Handle<GlobalObject*> global = obj.as<GlobalObject>(); + if (!GlobalObject::ensureConstructor(cx, global, JSProto_Object)) { + return false; + } + } + + /* + * 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 (!SetProto(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); +} + +bool js::PreventExtensions(JSContext* cx, HandleObject obj, + ObjectOpResult& result) { + if (obj->is<ProxyObject>()) { + return js::Proxy::preventExtensions(cx, obj, result); + } + + 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. + HandleNativeObject 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 NOT_EXTENSIBLE flag on the BaseShape and ObjectElements. + if (!JSObject::setFlags(cx, obj, BaseShape::NOT_EXTENSIBLE, + JSObject::GENERATE_SHAPE)) { + 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<PropertyDescriptor> desc) { + if (GetOwnPropertyOp op = obj->getOpsGetOwnPropertyDescriptor()) { + bool ok = op(cx, obj, id, desc); + if (ok) { + desc.assertCompleteIfFound(); + } + 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); + + { + GetterOp getterOp = JS_DATA_TO_FUNC_PTR(GetterOp, getter.get()); + SetterOp setterOp = JS_DATA_TO_FUNC_PTR(SetterOp, setter.get()); + desc.initFields(nullptr, UndefinedHandleValue, attrs, getterOp, setterOp); + } + + if (DefinePropertyOp op = obj->getOpsDefineProperty()) { + MOZ_ASSERT(!cx->isHelperThreadContext()); + 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); + desc.initFields(nullptr, value, attrs, nullptr, nullptr); + if (DefinePropertyOp op = obj->getOpsDefineProperty()) { + MOZ_ASSERT(!cx->isHelperThreadContext()); + 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) { + MOZ_ASSERT(!cx->isHelperThreadContext()); + 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) { + MOZ_ASSERT(!cx->isHelperThreadContext()); + 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()) { + MOZ_ASSERT(!cx->isHelperThreadContext()); + return Proxy::setImmutablePrototype(cx, obj, succeeded); + } + + if (!JSObject::setFlags(cx, obj, BaseShape::IMMUTABLE_PROTOTYPE)) { + return false; + } + *succeeded = true; + return true; +} + +bool js::GetPropertyDescriptor(JSContext* cx, HandleObject obj, HandleId id, + MutableHandle<PropertyDescriptor> desc) { + RootedObject pobj(cx); + + for (pobj = obj; pobj;) { + if (!GetOwnPropertyDescriptor(cx, pobj, id, desc)) { + return false; + } + + if (desc.object()) { + return true; + } + + if (!GetPrototype(cx, pobj, &pobj)) { + return false; + } + } + + MOZ_ASSERT(!desc.object()); + return true; +} + +/* * */ + +extern bool PropertySpecNameToId(JSContext* cx, JSPropertySpec::Name name, + MutableHandleId id, + js::PinningBehavior pin = js::DoNotPinAtom); + +// 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_FRIEND_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 && + cx->realm()->creationOptions().getWeakRefsEnabled() == + JS::WeakRefSpecifier::EnabledWithoutCleanupSome && + id == NameToId(cx->names().cleanupSome)) { + return true; + } + + return false; +} + +static bool DefineFunctionFromSpec(JSContext* cx, HandleObject obj, + const JSFunctionSpec* fs, unsigned flags, + DefineAsIntrinsic intrinsic) { + 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; + } + + if (intrinsic == AsIntrinsic) { + fun->setIsIntrinsic(); + } + + RootedValue funVal(cx, ObjectValue(*fun)); + return DefineDataProperty(cx, obj, id, funVal, flags & ~JSFUN_FLAGS_MASK); +} + +bool js::DefineFunctions(JSContext* cx, HandleObject obj, + const JSFunctionSpec* fs, + DefineAsIntrinsic intrinsic) { + for (; fs->name; fs++) { + if (!DefineFunctionFromSpec(cx, obj, fs, fs->flags, intrinsic)) { + 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_AtomizeAndPinString(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); + + /* Optimize (new String(...)).toString(). */ + if (clasp == &StringObject::class_) { + StringObject* nobj = &obj->as<StringObject>(); + if (HasNativeMethodPure(nobj, cx->names().toString, str_toString, cx)) { + vp.setString(nobj->unbox()); + return true; + } + } + + 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); + + /* Optimize new String(...).valueOf(). */ + if (clasp == &StringObject::class_) { + StringObject* nobj = &obj->as<StringObject>(); + if (HasNativeMethodPure(nobj, cx->names().valueOf, str_toString, cx)) { + vp.setString(nobj->unbox()); + return true; + } + } + + /* Optimize new Number(...).valueOf(). */ + if (clasp == &NumberObject::class_) { + NumberObject* nobj = &obj->as<NumberObject>(); + if (HasNativeMethodPure(nobj, cx->names().valueOf, num_valueOf, cx)) { + vp.setNumber(nobj->unbox()); + 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); + } + 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; + 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, + HandlePropertyName 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); +} + +JSObject* js::GetThisObject(JSObject* obj) { + // Use the WindowProxy if the global is a Window, as Window must never be + // exposed to script. + if (obj->is<GlobalObject>()) { + return ToWindowProxyIfWindow(obj); + } + + // We should not expose any environments except NSVOs to script. The NSVO is + // pretending to be the global object in this case. + MOZ_ASSERT(obj->is<NonSyntacticVariablesObject>() || + !obj->is<EnvironmentObject>()); + + return obj; +} + +JSObject* js::GetThisObjectOfLexical(JSObject* env) { + MOZ_ASSERT(IsExtensibleLexicalEnvironment(env)); + return env->as<LexicalEnvironmentObject>().thisObject(); +} + +JSObject* js::GetThisObjectOfWith(JSObject* env) { + MOZ_ASSERT(env->is<WithEnvironmentObject>()); + return GetThisObject(env->as<WithEnvironmentObject>().withThis()); +} + +class GetObjectSlotNameFunctor : public JS::TracingContext::Functor { + JSObject* obj; + + public: + explicit GetObjectSlotNameFunctor(JSObject* ctx) : obj(ctx) {} + virtual void operator()(JS::TracingContext* trc, char* buf, + size_t bufsize) override; +}; + +void GetObjectSlotNameFunctor::operator()(JS::TracingContext* tcx, char* buf, + size_t bufsize) { + MOZ_ASSERT(tcx->index() != JS::TracingContext::InvalidIndex); + + uint32_t slot = uint32_t(tcx->index()); + + Shape* shape; + if (obj->isNative()) { + shape = obj->as<NativeObject>().lastProperty(); + while (shape && (shape->isEmptyShape() || !shape->isDataProperty() || + shape->slot() != slot)) { + shape = shape->previous(); + } + } else { + shape = nullptr; + } + + if (!shape) { + 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 = js_##name##_str; \ + } + 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 { + jsid propid = shape->propid(); + if (JSID_IS_INT(propid)) { + snprintf(buf, bufsize, "%" PRId32, JSID_TO_INT(propid)); + } else if (JSID_IS_ATOM(propid)) { + PutEscapedString(buf, bufsize, JSID_TO_ATOM(propid), 0); + } else if (JSID_IS_SYMBOL(propid)) { + 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 FRIEND_API to help + * the debugger find them and to support temporarily hacking js::Dump* calls + * into other code. + */ + +static void dumpValue(const Value& v, js::GenericPrinter& out) { + switch (v.type()) { + case ValueType::Null: + out.put("null"); + break; + case ValueType::Undefined: + out.put("undefined"); + break; + case ValueType::Int32: + out.printf("%d", v.toInt32()); + break; + case ValueType::Double: + out.printf("%g", v.toDouble()); + break; + case ValueType::String: + v.toString()->dumpNoNewline(out); + break; + case ValueType::Symbol: + v.toSymbol()->dump(out); + break; + case ValueType::BigInt: + v.toBigInt()->dump(out); + break; + case ValueType::Object: + if (v.toObject().is<JSFunction>()) { + JSFunction* fun = &v.toObject().as<JSFunction>(); + if (fun->displayAtom()) { + out.put("<function "); + EscapedStringPrinter(out, fun->displayAtom(), 0); + } else { + out.put("<unnamed function"); + } + if (fun->hasBaseScript()) { + BaseScript* script = fun->baseScript(); + out.printf(" (%s:%u)", script->filename() ? script->filename() : "", + script->lineno()); + } + out.printf(" at %p>", (void*)fun); + } else { + JSObject* obj = &v.toObject(); + const JSClass* clasp = obj->getClass(); + out.printf("<%s%s at %p>", clasp->name, + (clasp == &PlainObject::class_) ? "" : " object", + (void*)obj); + } + break; + case ValueType::Boolean: + if (v.toBoolean()) { + out.put("true"); + } else { + out.put("false"); + } + break; + case ValueType::Magic: + out.put("<magic"); + switch (v.whyMagic()) { + case JS_ELEMENTS_HOLE: + out.put(" elements hole"); + break; + case JS_NO_ITER_VALUE: + out.put(" no iter value"); + break; + case JS_GENERATOR_CLOSING: + out.put(" generator closing"); + break; + case JS_OPTIMIZED_OUT: + out.put(" optimized out"); + break; + default: + out.put(" ?!"); + break; + } + out.putChar('>'); + break; + case ValueType::PrivateGCThing: + out.printf("<PrivateGCThing %p>", v.toGCThing()); + break; + } +} + +namespace js { + +// We don't want jsfriendapi.h to depend on GenericPrinter, +// so these functions are declared directly in the cpp. + +JS_FRIEND_API void DumpValue(const JS::Value& val, js::GenericPrinter& out); + +JS_FRIEND_API void DumpId(jsid id, js::GenericPrinter& out); + +JS_FRIEND_API void DumpInterpreterFrame(JSContext* cx, js::GenericPrinter& out, + InterpreterFrame* start = nullptr); + +} // namespace js + +JS_FRIEND_API void js::DumpValue(const Value& val, js::GenericPrinter& out) { + dumpValue(val, out); + out.putChar('\n'); +} + +JS_FRIEND_API void js::DumpId(jsid id, js::GenericPrinter& out) { + out.printf("jsid %p = ", (void*)JSID_BITS(id)); + dumpValue(IdToValue(id), out); + out.putChar('\n'); +} + +static void DumpProperty(const NativeObject* obj, Shape& shape, + js::GenericPrinter& out) { + jsid id = shape.propid(); + if (JSID_IS_ATOM(id)) { + JSID_TO_ATOM(id)->dumpCharsNoNewline(out); + } else if (JSID_IS_INT(id)) { + out.printf("%d", JSID_TO_INT(id)); + } else if (JSID_IS_SYMBOL(id)) { + JSID_TO_SYMBOL(id)->dump(out); + } else { + out.printf("id %p", reinterpret_cast<void*>(JSID_BITS(id))); + } + + if (shape.isDataProperty()) { + out.printf(": "); + dumpValue(obj->getSlot(shape.maybeSlot()), out); + } + + out.printf(" (shape %p", (void*)&shape); + + uint8_t attrs = shape.attributes(); + if (attrs & JSPROP_ENUMERATE) out.put(" enumerate"); + if (attrs & JSPROP_READONLY) out.put(" readonly"); + if (attrs & JSPROP_PERMANENT) out.put(" permanent"); + + if (shape.hasGetterValue()) { + out.printf(" getterValue %p", shape.getterObject()); + } else if (!shape.hasDefaultGetter()) { + out.printf(" getterOp %p", JS_FUNC_TO_DATA_PTR(void*, shape.getterOp())); + } + + if (shape.hasSetterValue()) { + out.printf(" setterValue %p", shape.setterObject()); + } else if (!shape.hasDefaultSetter()) { + out.printf(" setterOp %p", JS_FUNC_TO_DATA_PTR(void*, shape.setterOp())); + } + + if (shape.isDataProperty()) { + out.printf(" slot %u", shape.maybeSlot()); + } + + out.printf(")\n"); +} + +bool JSObject::hasSameRealmAs(JSContext* cx) const { + return nonCCWRealm() == cx->realm(); +} + +bool JSObject::uninlinedIsProxy() const { return is<ProxyObject>(); } + +bool JSObject::uninlinedNonProxyIsExtensible() const { + return nonProxyIsExtensible(); +} + +void JSObject::dump(js::GenericPrinter& out) const { + const JSObject* obj = this; + out.printf("object %p\n", obj); + + if (IsCrossCompartmentWrapper(this)) { + out.printf(" compartment %p\n", compartment()); + } else { + JSObject* globalObj = &nonCCWGlobal(); + out.printf(" global %p [%s]\n", globalObj, globalObj->getClass()->name); + } + + const JSClass* clasp = obj->getClass(); + out.printf(" class %p %s\n", clasp, clasp->name); + + const ObjectGroup* group = obj->group(); + out.printf(" group %p\n", group); + + out.put(" flags:"); + if (obj->isDelegate()) out.put(" delegate"); + if (!obj->is<ProxyObject>() && !obj->nonProxyIsExtensible()) + out.put(" not_extensible"); + if (obj->maybeHasInterestingSymbolProperty()) + out.put(" maybe_has_interesting_symbol"); + if (obj->isBoundFunction()) out.put(" bound_function"); + if (obj->isQualifiedVarObj()) out.put(" varobj"); + if (obj->isUnqualifiedVarObj()) out.put(" unqualified_varobj"); + if (obj->hasUncacheableProto()) out.put(" has_uncacheable_proto"); + if (obj->hasStaticPrototype() && obj->staticPrototypeIsImmutable()) { + out.put(" immutable_prototype"); + } + + const NativeObject* nobj = + obj->isNative() ? &obj->as<NativeObject>() : nullptr; + if (nobj) { + if (nobj->inDictionaryMode()) { + out.put(" inDictionaryMode"); + } + if (nobj->hasShapeTable()) { + out.put(" hasShapeTable"); + } + if (nobj->hasShapeIC()) { + out.put(" hasShapeCache"); + } + if (nobj->hadElementsAccess()) { + out.put(" had_elements_access"); + } + if (nobj->isIndexed()) { + out.put(" indexed"); + } + if (!nobj->denseElementsArePacked()) { + out.put(" non_packed_elements"); + } + if (nobj->getElementsHeader()->isNotExtensible()) { + out.put(" not_extensible"); + } + if (nobj->getElementsHeader()->isSealed()) { + out.put(" sealed_elements"); + } + if (nobj->getElementsHeader()->isFrozen()) { + out.put(" frozen_elements"); + } + if (nobj->getElementsHeader()->maybeInIteration()) { + out.put(" elements_maybe_in_iteration"); + } + } else { + out.put(" not_native\n"); + } + out.putChar('\n'); + + out.put(" proto "); + TaggedProto proto = obj->taggedProto(); + if (proto.isDynamic()) { + out.put("<dynamic>"); + } else { + dumpValue(ObjectOrNullValue(proto.toObjectOrNull()), out); + } + out.putChar('\n'); + + if (nobj) { + if (clasp->flags & JSCLASS_HAS_PRIVATE) { + out.printf(" private %p\n", nobj->getPrivate()); + } + + uint32_t reserved = JSCLASS_RESERVED_SLOTS(clasp); + if (reserved) { + out.printf(" reserved slots:\n"); + for (uint32_t i = 0; i < reserved; i++) { + out.printf(" %3u ", i); + out.put(": "); + dumpValue(nobj->getSlot(i), out); + out.putChar('\n'); + } + } + + out.put(" properties:\n"); + Vector<Shape*, 8, SystemAllocPolicy> props; + for (Shape::Range<NoGC> r(nobj->lastProperty()); !r.empty(); r.popFront()) { + if (!props.append(&r.front())) { + out.printf("(OOM while appending properties)\n"); + break; + } + } + for (size_t i = props.length(); i-- != 0;) { + out.printf(" "); + DumpProperty(nobj, *props[i], out); + } + + uint32_t slots = nobj->getDenseInitializedLength(); + if (slots) { + out.put(" elements:\n"); + for (uint32_t i = 0; i < slots; i++) { + out.printf(" %3u: ", i); + dumpValue(nobj->getDenseElement(i), out); + out.putChar('\n'); + } + } + } +} + +// For debuggers. +void JSObject::dump() const { + Fprinter out(stderr); + dump(out); +} + +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(" "); + dumpValue(StringValue(bi.name()), out); + out.putChar('\n'); + } + } +} + +static void MaybeDumpValue(const char* name, const Value& v, + js::GenericPrinter& out) { + if (!v.isNull()) { + out.printf(" %s: ", name); + dumpValue(v, out); + out.putChar('\n'); + } +} + +JS_FRIEND_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); + dumpValue(v, out); + } else { + out.put("global or eval frame, no callee"); + } + out.putChar('\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: "); + dumpValue(i.interpFrame()->returnValue(), out); + out.putChar('\n'); + } + + 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) */ + +namespace js { + +// We don't want jsfriendapi.h to depend on GenericPrinter, +// so these functions are declared directly in the cpp. + +JS_FRIEND_API void DumpBacktrace(JSContext* cx, js::GenericPrinter& out); + +} // namespace js + +JS_FRIEND_API void js::DumpBacktrace(JSContext* cx, FILE* fp) { + Fprinter out(fp); + js::DumpBacktrace(cx, out); +} + +JS_FRIEND_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_FRIEND_API void js::DumpBacktrace(JSContext* cx) { + DumpBacktrace(cx, stdout); +} + +/* * */ + +js::gc::AllocKind JSObject::allocKindForTenure( + const js::Nursery& nursery) const { + using namespace js::gc; + + MOZ_ASSERT(IsInsideNursery(this)); + + if (is<ArrayObject>()) { + const ArrayObject& aobj = as<ArrayObject>(); + MOZ_ASSERT(aobj.numFixedSlots() == 0); + + /* Use minimal size object if we are just going to copy the pointer. */ + if (!nursery.isInside(aobj.getElementsHeader())) { + return gc::AllocKind::OBJECT0_BACKGROUND; + } + + size_t nelements = aobj.getDenseCapacity(); + return ForegroundToBackgroundAllocKind(GetGCArrayKind(nelements)); + } + + if (is<JSFunction>()) { + return as<JSFunction>().getAllocKind(); + } + + /* + * Typed arrays in the nursery may have a lazily allocated buffer, make + * sure there is room for the array's fixed data when moving the array. + */ + if (is<TypedArrayObject>() && !as<TypedArrayObject>().hasBuffer()) { + gc::AllocKind allocKind; + if (as<TypedArrayObject>().hasInlineElements()) { + size_t nbytes = as<TypedArrayObject>().byteLength().get(); + allocKind = TypedArrayObject::AllocKindForLazyBuffer(nbytes); + } else { + allocKind = GetGCObjectKind(getClass()); + } + return ForegroundToBackgroundAllocKind(allocKind); + } + + // Proxies that are CrossCompartmentWrappers may be nursery allocated. + if (IsProxy(this)) { + return as<ProxyObject>().allocKindForTenure(); + } + + // Inlined typed objects are followed by their data, so make sure we copy + // it all over to the new object. + if (is<InlineTypedObject>()) { + // Figure out the size of this object, from the prototype's TypeDescr. + // The objects we are traversing here are all tenured, so we don't need + // to check forwarding pointers. + TypeDescr& descr = as<InlineTypedObject>().typeDescr(); + MOZ_ASSERT(!IsInsideNursery(&descr)); + return InlineTypedObject::allocKindForTypeDescriptor(&descr); + } + + // Outline typed objects use the minimum allocation kind. + if (is<OutlineTypedObject>()) { + return gc::AllocKind::OBJECT0; + } + + // All nursery allocatable non-native objects are handled above. + return as<NativeObject>().allocKindForTenure(); +} + +void JSObject::addSizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf, + JS::ClassInfo* info) { + 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_CALLBACK 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<RegExpStaticsObject>()) { + info->objectsMallocHeapMisc += + as<RegExpStaticsObject>().sizeOfData(mallocSizeOf); + } else if (is<PropertyIteratorObject>()) { + info->objectsMallocHeapMisc += + as<PropertyIteratorObject>().sizeOfMisc(mallocSizeOf); + } else if (is<ArrayBufferObject>()) { + ArrayBufferObject::addSizeOfExcludingThis(this, mallocSizeOf, info); + } else if (is<SharedArrayBufferObject>()) { + SharedArrayBufferObject::addSizeOfExcludingThis(this, 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.numFixedSlots() * sizeof(Value); + 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); + return obj.tenuredSizeOfThis() + info.sizeOfAllThings(); +} + +const char16_t JS::ubi::Concrete<JSObject>::concreteTypeName[] = u"JSObject"; + +void JSObject::traceChildren(JSTracer* trc) { + TraceCellHeaderEdge(trc, this, "group"); + + traceShape(trc); + + const JSClass* clasp = group()->clasp(); + if (clasp->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. + if (clasp->hasTrace()) { + clasp->doTrace(trc, this); + } + + if (trc->isMarkingTracer()) { + GCMarker::fromTracer(trc)->markImplicitEdges(this); + } +} + +// ES 2016 7.3.20. +MOZ_MUST_USE 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 = SYMBOL_TO_JSID(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, SYMBOL_TO_JSID(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; +} + +MOZ_MUST_USE 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()); + } else { + vp.setUndefined(); + } + + return true; +} + +#ifdef DEBUG +/* static */ +void JSObject::debugCheckNewObject(ObjectGroup* group, Shape* shape, + js::gc::AllocKind allocKind, + js::gc::InitialHeap heap) { + const JSClass* clasp = group->clasp(); + MOZ_ASSERT(clasp != &ArrayObject::class_); + + MOZ_ASSERT_IF(shape, clasp == shape->getObjectClass()); + + if (!ClassCanHaveFixedData(clasp)) { + MOZ_ASSERT(shape); + MOZ_ASSERT(gc::GetGCKindSlots(allocKind, clasp) == shape->numFixedSlots()); + } + + // 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->isProxy()) { + 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::TenuredHeap || + CanNurseryAllocateFinalizedClass(clasp) || + clasp->isProxy()); + + MOZ_ASSERT(!group->realm()->hasObjectPendingMetadata()); + + // Non-native classes manage their own data and slots, so numFixedSlots and + // slotSpan are always 0. Note that proxy classes can have reserved slots + // but they're also not included in numFixedSlots/slotSpan. + if (!clasp->isNative()) { + MOZ_ASSERT_IF(!clasp->isProxy(), JSCLASS_RESERVED_SLOTS(clasp) == 0); + MOZ_ASSERT(!clasp->hasPrivate()); + MOZ_ASSERT_IF(shape, shape->numFixedSlots() == 0); + MOZ_ASSERT_IF(shape, shape->slotSpan() == 0); + } +} +#endif |