js/src/vm/JSObject-inl.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  * vim: set ts=8 sts=2 et sw=2 tw=80:
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef vm_JSObject_inl_h
   8 #define vm_JSObject_inl_h
   9
  10 #include "vm/JSObject.h"
  11
  12 #include "js/Object.h"  // JS::GetBuiltinClass
  13 #include "vm/ArrayObject.h"
  14 #include "vm/BoundFunctionObject.h"
  15 #include "vm/EnvironmentObject.h"
  16 #include "vm/JSFunction.h"
  17 #include "vm/Probes.h"
  18 #include "vm/PropertyResult.h"
  19 #include "vm/TypedArrayObject.h"
  20
  21 #ifdef ENABLE_RECORD_TUPLE
  22 #  include "vm/TupleType.h"
  23 #endif
  24
  25 #include "gc/GCContext-inl.h"
  26 #include "gc/ObjectKind-inl.h"
  27 #include "vm/ObjectOperations-inl.h"  // js::MaybeHasInterestingSymbolProperty
  28
  29 namespace js {
  30
  31 #ifdef ENABLE_RECORD_TUPLE
  32 // Defined in vm/RecordTupleShared.{h,cpp}. We cannot include that file
  33 // because it causes circular dependencies.
  34 extern bool IsExtendedPrimitiveWrapper(const JSObject& obj);
  35 #endif
  36
  37 // Get the GC kind to use for scripted 'new', empty object literals ({}), and
  38 // the |Object| constructor.
  39 static inline gc::AllocKind NewObjectGCKind() { return gc::AllocKind::OBJECT4; }
  40
  41 }  // namespace js
  42
  43 MOZ_ALWAYS_INLINE uint32_t js::NativeObject::numDynamicSlots() const {
  44   uint32_t slots = getSlotsHeader()->capacity();
  45   MOZ_ASSERT(slots == calculateDynamicSlots());
  46   MOZ_ASSERT_IF(hasDynamicSlots() && !hasUniqueId(), slots != 0);
  47
  48   return slots;
  49 }
  50
  51 MOZ_ALWAYS_INLINE uint32_t js::NativeObject::calculateDynamicSlots() const {
  52   return calculateDynamicSlots(numFixedSlots(), slotSpan(), getClass());
  53 }
  54
  55 /* static */ MOZ_ALWAYS_INLINE uint32_t js::NativeObject::calculateDynamicSlots(
  56     uint32_t nfixed, uint32_t span, const JSClass* clasp) {
  57   if (span <= nfixed) {
  58     return 0;
  59   }
  60
  61   uint32_t ndynamic = span - nfixed;
  62
  63   // Increase the slots to SLOT_CAPACITY_MIN to decrease the likelihood
  64   // the dynamic slots need to get increased again. ArrayObjects ignore
  65   // this because slots are uncommon in that case.
  66   if (clasp != &ArrayObject::class_ && ndynamic <= SLOT_CAPACITY_MIN) {
  67     return SLOT_CAPACITY_MIN;
  68   }
  69
  70   uint32_t count =
  71       mozilla::RoundUpPow2(ndynamic + ObjectSlots::VALUES_PER_HEADER);
  72
  73   uint32_t slots = count - ObjectSlots::VALUES_PER_HEADER;
  74   MOZ_ASSERT(slots >= ndynamic);
  75   return slots;
  76 }
  77
  78 /* static */ MOZ_ALWAYS_INLINE uint32_t
  79 js::NativeObject::calculateDynamicSlots(SharedShape* shape) {
  80   return calculateDynamicSlots(shape->numFixedSlots(), shape->slotSpan(),
  81                                shape->getObjectClass());
  82 }
  83
  84 inline void JSObject::finalize(JS::GCContext* gcx) {
  85   js::probes::FinalizeObject(this);
  86
  87 #ifdef DEBUG
  88   MOZ_ASSERT(isTenured());
  89   if (!IsBackgroundFinalized(asTenured().getAllocKind())) {
  90     /* Assert we're on the main thread. */
  91     MOZ_ASSERT(CurrentThreadCanAccessZone(zone()));
  92   }
  93 #endif
  94
  95   js::Shape* objShape = shape();
  96
  97   const JSClass* clasp = objShape->getObjectClass();
  98   if (clasp->hasFinalize()) {
  99     clasp->doFinalize(gcx, this);
 100   }
 101
 102   if (!objShape->isNative()) {
 103     return;
 104   }
 105
 106   js::NativeObject* nobj = &as<js::NativeObject>();
 107   if (nobj->hasDynamicSlots()) {
 108     js::ObjectSlots* slotsHeader = nobj->getSlotsHeader();
 109     size_t size = js::ObjectSlots::allocSize(slotsHeader->capacity());
 110     gcx->free_(this, slotsHeader, size, js::MemoryUse::ObjectSlots);
 111   }
 112
 113   if (nobj->hasDynamicElements()) {
 114     js::ObjectElements* elements = nobj->getElementsHeader();
 115     size_t size = elements->numAllocatedElements() * sizeof(js::HeapSlot);
 116     gcx->free_(this, nobj->getUnshiftedElementsHeader(), size,
 117                js::MemoryUse::ObjectElements);
 118   }
 119 }
 120
 121 inline bool JSObject::isQualifiedVarObj() const {
 122   if (is<js::DebugEnvironmentProxy>()) {
 123     return as<js::DebugEnvironmentProxy>().environment().isQualifiedVarObj();
 124   }
 125   bool rv = hasFlag(js::ObjectFlag::QualifiedVarObj);
 126   MOZ_ASSERT_IF(rv, is<js::GlobalObject>() || is<js::CallObject>() ||
 127                         is<js::VarEnvironmentObject>() ||
 128                         is<js::ModuleEnvironmentObject>() ||
 129                         is<js::NonSyntacticVariablesObject>() ||
 130                         (is<js::WithEnvironmentObject>() &&
 131                          !as<js::WithEnvironmentObject>().isSyntactic()));
 132   return rv;
 133 }
 134
 135 inline bool JSObject::isUnqualifiedVarObj() const {
 136   if (is<js::DebugEnvironmentProxy>()) {
 137     return as<js::DebugEnvironmentProxy>().environment().isUnqualifiedVarObj();
 138   }
 139   return is<js::GlobalObject>() || is<js::NonSyntacticVariablesObject>();
 140 }
 141
 142 inline bool JSObject::canHaveFixedElements() const {
 143   return (is<js::ArrayObject>() || IF_RECORD_TUPLE(is<js::TupleType>(), false));
 144 }
 145
 146 namespace js {
 147
 148 #ifdef DEBUG
 149 inline bool ClassCanHaveFixedData(const JSClass* clasp) {
 150   // Normally, the number of fixed slots given an object is the maximum
 151   // permitted for its size class. For array buffers and typed arrays we only
 152   // use enough to cover the class reserved slots, so that the remaining space
 153   // in the object's allocation is available for the buffer's data.
 154   return !clasp->isNativeObject() ||
 155          clasp == &js::FixedLengthArrayBufferObject::class_ ||
 156          clasp == &js::ResizableArrayBufferObject::class_ ||
 157          js::IsTypedArrayClass(clasp);
 158 }
 159 #endif
 160
 161 class MOZ_RAII AutoSuppressAllocationMetadataBuilder {
 162   JS::Zone* zone;
 163   bool saved;
 164
 165  public:
 166   explicit AutoSuppressAllocationMetadataBuilder(JSContext* cx)
 167       : zone(cx->zone()), saved(zone->suppressAllocationMetadataBuilder) {
 168     zone->suppressAllocationMetadataBuilder = true;
 169   }
 170
 171   ~AutoSuppressAllocationMetadataBuilder() {
 172     zone->suppressAllocationMetadataBuilder = saved;
 173   }
 174 };
 175
 176 // This function is meant to be called from allocation fast paths.
 177 //
 178 // If we do have an allocation metadata builder, it can cause a GC, so the
 179 // object must be rooted. The usual way to do this would be to make our callers
 180 // pass a HandleObject, but that would require them to pay the cost of rooting
 181 // the object unconditionally, even though collecting metadata is rare. Instead,
 182 // SetNewObjectMetadata's contract is that the caller must use the pointer
 183 // returned in place of the pointer passed. If a GC occurs, the returned pointer
 184 // may be the passed pointer, relocated by GC. If no GC could occur, it's just
 185 // passed through. We root nothing unless necessary.
 186 template <typename T>
 187 [[nodiscard]] static inline T* SetNewObjectMetadata(JSContext* cx, T* obj) {
 188   MOZ_ASSERT(cx->realm()->hasAllocationMetadataBuilder());
 189   MOZ_ASSERT(!cx->realm()->hasObjectPendingMetadata());
 190
 191   // The metadata builder is invoked for each object created on the main thread,
 192   // except when it's suppressed.
 193   if (!cx->zone()->suppressAllocationMetadataBuilder) {
 194     // Don't collect metadata on objects that represent metadata, to avoid
 195     // recursion.
 196     AutoSuppressAllocationMetadataBuilder suppressMetadata(cx);
 197
 198     Rooted<T*> rooted(cx, obj);
 199     cx->realm()->setNewObjectMetadata(cx, rooted);
 200     return rooted;
 201   }
 202
 203   return obj;
 204 }
 205
 206 }  // namespace js
 207
 208 inline js::GlobalObject& JSObject::nonCCWGlobal() const {
 209   /*
 210    * The global is read-barriered so that it is kept live by access through
 211    * the Realm. When accessed through a JSObject, however, the global will be
 212    * already kept live by the black JSObject's group pointer, so does not
 213    * need to be read-barriered.
 214    */
 215   return *nonCCWRealm()->unsafeUnbarrieredMaybeGlobal();
 216 }
 217
 218 inline bool JSObject::nonProxyIsExtensible() const {
 219   MOZ_ASSERT(!uninlinedIsProxyObject());
 220
 221 #ifdef ENABLE_RECORD_TUPLE
 222   if (js::IsExtendedPrimitiveWrapper(*this)) {
 223     return false;
 224   }
 225 #endif
 226   // [[Extensible]] for ordinary non-proxy objects is an object flag.
 227   return !hasFlag(js::ObjectFlag::NotExtensible);
 228 }
 229
 230 inline bool JSObject::hasInvalidatedTeleporting() const {
 231   return hasFlag(js::ObjectFlag::InvalidatedTeleporting);
 232 }
 233
 234 inline bool JSObject::needsProxyGetSetResultValidation() const {
 235   return hasFlag(js::ObjectFlag::NeedsProxyGetSetResultValidation);
 236 }
 237
 238 MOZ_ALWAYS_INLINE bool JSObject::maybeHasInterestingSymbolProperty() const {
 239   if (is<js::NativeObject>()) {
 240     return as<js::NativeObject>().hasInterestingSymbol();
 241   }
 242   return true;
 243 }
 244
 245 inline bool JSObject::staticPrototypeIsImmutable() const {
 246   MOZ_ASSERT(hasStaticPrototype());
 247   return hasFlag(js::ObjectFlag::ImmutablePrototype);
 248 }
 249
 250 namespace js {
 251
 252 static MOZ_ALWAYS_INLINE bool IsFunctionObject(const js::Value& v) {
 253   return v.isObject() && v.toObject().is<JSFunction>();
 254 }
 255
 256 static MOZ_ALWAYS_INLINE bool IsFunctionObject(const js::Value& v,
 257                                                JSFunction** fun) {
 258   if (v.isObject() && v.toObject().is<JSFunction>()) {
 259     *fun = &v.toObject().as<JSFunction>();
 260     return true;
 261   }
 262   return false;
 263 }
 264
 265 static MOZ_ALWAYS_INLINE bool IsNativeFunction(const js::Value& v,
 266                                                JSNative native) {
 267   JSFunction* fun;
 268   return IsFunctionObject(v, &fun) && fun->maybeNative() == native;
 269 }
 270
 271 static MOZ_ALWAYS_INLINE bool IsNativeFunction(const JSObject* obj,
 272                                                JSNative native) {
 273   return obj->is<JSFunction>() && obj->as<JSFunction>().maybeNative() == native;
 274 }
 275
 276 // Return whether looking up a method on 'obj' definitely resolves to the
 277 // original specified native function. The method may conservatively return
 278 // 'false' in the case of proxies or other non-native objects.
 279 static MOZ_ALWAYS_INLINE bool HasNativeMethodPure(JSObject* obj,
 280                                                   PropertyName* name,
 281                                                   JSNative native,
 282                                                   JSContext* cx) {
 283   Value v;
 284   if (!GetPropertyPure(cx, obj, NameToId(name), &v)) {
 285     return false;
 286   }
 287
 288   return IsNativeFunction(v, native);
 289 }
 290
 291 // Return whether 'obj' definitely has no @@toPrimitive method.
 292 static MOZ_ALWAYS_INLINE bool HasNoToPrimitiveMethodPure(JSObject* obj,
 293                                                          JSContext* cx) {
 294   JS::Symbol* toPrimitive = cx->wellKnownSymbols().toPrimitive;
 295   JSObject* holder;
 296   if (!MaybeHasInterestingSymbolProperty(cx, obj, toPrimitive, &holder)) {
 297 #ifdef DEBUG
 298     NativeObject* pobj;
 299     PropertyResult prop;
 300     MOZ_ASSERT(LookupPropertyPure(cx, obj, PropertyKey::Symbol(toPrimitive),
 301                                   &pobj, &prop));
 302     MOZ_ASSERT(prop.isNotFound());
 303 #endif
 304     return true;
 305   }
 306
 307   NativeObject* pobj;
 308   PropertyResult prop;
 309   if (!LookupPropertyPure(cx, holder, PropertyKey::Symbol(toPrimitive), &pobj,
 310                           &prop)) {
 311     return false;
 312   }
 313
 314   return prop.isNotFound();
 315 }
 316
 317 extern bool ToPropertyKeySlow(JSContext* cx, HandleValue argument,
 318                               MutableHandleId result);
 319
 320 /* ES6 draft rev 28 (2014 Oct 14) 7.1.14 */
 321 MOZ_ALWAYS_INLINE bool ToPropertyKey(JSContext* cx, HandleValue argument,
 322                                      MutableHandleId result) {
 323   if (MOZ_LIKELY(argument.isPrimitive())) {
 324     return PrimitiveValueToId<CanGC>(cx, argument, result);
 325   }
 326
 327   return ToPropertyKeySlow(cx, argument, result);
 328 }
 329
 330 /*
 331  * Return true if this is a compiler-created internal function accessed by
 332  * its own object. Such a function object must not be accessible to script
 333  * or embedding code.
 334  */
 335 inline bool IsInternalFunctionObject(JSObject& funobj) {
 336   JSFunction& fun = funobj.as<JSFunction>();
 337   return fun.isInterpreted() && !fun.environment();
 338 }
 339
 340 inline gc::Heap GetInitialHeap(NewObjectKind newKind, const JSClass* clasp,
 341                                gc::AllocSite* site = nullptr) {
 342   if (newKind != GenericObject) {
 343     return gc::Heap::Tenured;
 344   }
 345   if (clasp->hasFinalize() && !CanNurseryAllocateFinalizedClass(clasp)) {
 346     return gc::Heap::Tenured;
 347   }
 348   if (site) {
 349     return site->initialHeap();
 350   }
 351   return gc::Heap::Default;
 352 }
 353
 354 /*
 355  * Make an object with the specified prototype. If parent is null, it will
 356  * default to the prototype's global if the prototype is non-null.
 357  */
 358 NativeObject* NewObjectWithGivenTaggedProto(JSContext* cx, const JSClass* clasp,
 359                                             Handle<TaggedProto> proto,
 360                                             gc::AllocKind allocKind,
 361                                             NewObjectKind newKind,
 362                                             ObjectFlags objFlags);
 363
 364 template <NewObjectKind NewKind>
 365 inline NativeObject* NewObjectWithGivenTaggedProto(JSContext* cx,
 366                                                    const JSClass* clasp,
 367                                                    Handle<TaggedProto> proto,
 368                                                    ObjectFlags objFlags) {
 369   gc::AllocKind allocKind = gc::GetGCObjectKind(clasp);
 370   return NewObjectWithGivenTaggedProto(cx, clasp, proto, allocKind, NewKind,
 371                                        objFlags);
 372 }
 373
 374 namespace detail {
 375
 376 template <typename T, NewObjectKind NewKind>
 377 inline T* NewObjectWithGivenTaggedProtoForKind(JSContext* cx,
 378                                                Handle<TaggedProto> proto) {
 379   JSObject* obj = NewObjectWithGivenTaggedProto<NewKind>(cx, &T::class_, proto,
 380                                                          ObjectFlags());
 381   return obj ? &obj->as<T>() : nullptr;
 382 }
 383
 384 }  // namespace detail
 385
 386 template <typename T>
 387 inline T* NewObjectWithGivenTaggedProto(JSContext* cx,
 388                                         Handle<TaggedProto> proto) {
 389   return detail::NewObjectWithGivenTaggedProtoForKind<T, GenericObject>(cx,
 390                                                                         proto);
 391 }
 392
 393 inline NativeObject* NewObjectWithGivenProto(JSContext* cx,
 394                                              const JSClass* clasp,
 395                                              HandleObject proto) {
 396   return NewObjectWithGivenTaggedProto<GenericObject>(
 397       cx, clasp, AsTaggedProto(proto), ObjectFlags());
 398 }
 399
 400 inline NativeObject* NewTenuredObjectWithGivenProto(
 401     JSContext* cx, const JSClass* clasp, HandleObject proto,
 402     ObjectFlags objFlags = ObjectFlags()) {
 403   return NewObjectWithGivenTaggedProto<TenuredObject>(
 404       cx, clasp, AsTaggedProto(proto), objFlags);
 405 }
 406
 407 template <typename T>
 408 inline T* NewObjectWithGivenProto(JSContext* cx, HandleObject proto) {
 409   return detail::NewObjectWithGivenTaggedProtoForKind<T, GenericObject>(
 410       cx, AsTaggedProto(proto));
 411 }
 412
 413 template <typename T>
 414 inline T* NewTenuredObjectWithGivenProto(JSContext* cx, HandleObject proto) {
 415   return detail::NewObjectWithGivenTaggedProtoForKind<T, TenuredObject>(
 416       cx, AsTaggedProto(proto));
 417 }
 418
 419 template <typename T>
 420 inline T* NewObjectWithGivenProtoAndKinds(JSContext* cx, HandleObject proto,
 421                                           gc::AllocKind allocKind,
 422                                           NewObjectKind newKind) {
 423   JSObject* obj = NewObjectWithGivenTaggedProto(
 424       cx, &T::class_, AsTaggedProto(proto), allocKind, newKind);
 425   return obj ? &obj->as<T>() : nullptr;
 426 }
 427
 428 // Make an object with the prototype set according to the cached prototype or
 429 // Object.prototype.
 430 NativeObject* NewObjectWithClassProto(JSContext* cx, const JSClass* clasp,
 431                                       HandleObject proto,
 432                                       gc::AllocKind allocKind,
 433                                       NewObjectKind newKind = GenericObject,
 434                                       ObjectFlags objFlags = ObjectFlags());
 435
 436 inline NativeObject* NewObjectWithClassProto(
 437     JSContext* cx, const JSClass* clasp, HandleObject proto,
 438     NewObjectKind newKind = GenericObject,
 439     ObjectFlags objFlags = ObjectFlags()) {
 440   gc::AllocKind allocKind = gc::GetGCObjectKind(clasp);
 441   return NewObjectWithClassProto(cx, clasp, proto, allocKind, newKind,
 442                                  objFlags);
 443 }
 444
 445 template <class T>
 446 inline T* NewObjectWithClassProto(JSContext* cx, HandleObject proto) {
 447   JSObject* obj = NewObjectWithClassProto(cx, &T::class_, proto, GenericObject);
 448   return obj ? &obj->as<T>() : nullptr;
 449 }
 450
 451 template <class T>
 452 inline T* NewObjectWithClassProtoAndKind(JSContext* cx, HandleObject proto,
 453                                          NewObjectKind newKind,
 454                                          ObjectFlags objFlags = ObjectFlags()) {
 455   JSObject* obj =
 456       NewObjectWithClassProto(cx, &T::class_, proto, newKind, objFlags);
 457   return obj ? &obj->as<T>() : nullptr;
 458 }
 459
 460 template <class T>
 461 inline T* NewObjectWithClassProto(JSContext* cx, HandleObject proto,
 462                                   gc::AllocKind allocKind,
 463                                   NewObjectKind newKind = GenericObject) {
 464   NativeObject* obj =
 465       NewObjectWithClassProto(cx, &T::class_, proto, allocKind, newKind);
 466   return obj ? &obj->as<T>() : nullptr;
 467 }
 468
 469 /*
 470  * Create a native instance of the given class with parent and proto set
 471  * according to the context's active global.
 472  */
 473 inline NativeObject* NewBuiltinClassInstance(
 474     JSContext* cx, const JSClass* clasp, gc::AllocKind allocKind,
 475     NewObjectKind newKind = GenericObject) {
 476   return NewObjectWithClassProto(cx, clasp, nullptr, allocKind, newKind);
 477 }
 478
 479 inline NativeObject* NewBuiltinClassInstance(
 480     JSContext* cx, const JSClass* clasp,
 481     NewObjectKind newKind = GenericObject) {
 482   gc::AllocKind allocKind = gc::GetGCObjectKind(clasp);
 483   return NewBuiltinClassInstance(cx, clasp, allocKind, newKind);
 484 }
 485
 486 template <typename T>
 487 inline T* NewBuiltinClassInstance(JSContext* cx) {
 488   JSObject* obj = NewBuiltinClassInstance(cx, &T::class_, GenericObject);
 489   return obj ? &obj->as<T>() : nullptr;
 490 }
 491
 492 template <typename T>
 493 inline T* NewTenuredBuiltinClassInstance(JSContext* cx) {
 494   JSObject* obj = NewBuiltinClassInstance(cx, &T::class_, TenuredObject);
 495   return obj ? &obj->as<T>() : nullptr;
 496 }
 497
 498 template <typename T>
 499 inline T* NewBuiltinClassInstanceWithKind(JSContext* cx,
 500                                           NewObjectKind newKind) {
 501   JSObject* obj = NewBuiltinClassInstance(cx, &T::class_, newKind);
 502   return obj ? &obj->as<T>() : nullptr;
 503 }
 504
 505 template <typename T>
 506 inline T* NewBuiltinClassInstance(JSContext* cx, gc::AllocKind allocKind,
 507                                   NewObjectKind newKind = GenericObject) {
 508   JSObject* obj = NewBuiltinClassInstance(cx, &T::class_, allocKind, newKind);
 509   return obj ? &obj->as<T>() : nullptr;
 510 }
 511
 512 static inline gc::AllocKind GuessArrayGCKind(size_t numElements) {
 513   if (numElements) {
 514     return gc::GetGCArrayKind(numElements);
 515   }
 516   return gc::AllocKind::OBJECT8;
 517 }
 518
 519 // Returns ESClass::Other if the value isn't an object, or if the object
 520 // isn't of one of the enumerated classes.  Otherwise returns the appropriate
 521 // class.
 522 inline bool GetClassOfValue(JSContext* cx, HandleValue v, ESClass* cls) {
 523   if (!v.isObject()) {
 524     *cls = ESClass::Other;
 525     return true;
 526   }
 527
 528   RootedObject obj(cx, &v.toObject());
 529   return JS::GetBuiltinClass(cx, obj, cls);
 530 }
 531
 532 extern NativeObject* InitClass(
 533     JSContext* cx, HandleObject obj, const JSClass* protoClass,
 534     HandleObject protoProto, const char* name, JSNative constructor,
 535     unsigned nargs, const JSPropertySpec* ps, const JSFunctionSpec* fs,
 536     const JSPropertySpec* static_ps, const JSFunctionSpec* static_fs,
 537     NativeObject** ctorp = nullptr);
 538
 539 MOZ_ALWAYS_INLINE const char* GetObjectClassName(JSContext* cx,
 540                                                  HandleObject obj) {
 541   if (obj->is<ProxyObject>()) {
 542     return Proxy::className(cx, obj);
 543   }
 544
 545   return obj->getClass()->name;
 546 }
 547
 548 inline bool IsCallable(const Value& v) {
 549   return v.isObject() && v.toObject().isCallable();
 550 }
 551
 552 // ES6 rev 24 (2014 April 27) 7.2.5 IsConstructor
 553 inline bool IsConstructor(const Value& v) {
 554   return v.isObject() && v.toObject().isConstructor();
 555 }
 556
 557 static inline bool MaybePreserveDOMWrapper(JSContext* cx, HandleObject obj) {
 558   if (!obj->getClass()->isDOMClass()) {
 559     return true;
 560   }
 561
 562   MOZ_ASSERT(cx->runtime()->preserveWrapperCallback);
 563   return cx->runtime()->preserveWrapperCallback(cx, obj);
 564 }
 565
 566 } /* namespace js */
 567
 568 MOZ_ALWAYS_INLINE bool JSObject::isCallable() const {
 569   if (is<JSFunction>()) {
 570     return true;
 571   }
 572   if (is<js::ProxyObject>()) {
 573     const js::ProxyObject& p = as<js::ProxyObject>();
 574     return p.handler()->isCallable(const_cast<JSObject*>(this));
 575   }
 576   return callHook() != nullptr;
 577 }
 578
 579 MOZ_ALWAYS_INLINE bool JSObject::isConstructor() const {
 580   if (is<JSFunction>()) {
 581     const JSFunction& fun = as<JSFunction>();
 582     return fun.isConstructor();
 583   }
 584   if (is<js::BoundFunctionObject>()) {
 585     const js::BoundFunctionObject& bound = as<js::BoundFunctionObject>();
 586     return bound.isConstructor();
 587   }
 588   if (is<js::ProxyObject>()) {
 589     const js::ProxyObject& p = as<js::ProxyObject>();
 590     return p.handler()->isConstructor(const_cast<JSObject*>(this));
 591   }
 592   return constructHook() != nullptr;
 593 }
 594
 595 MOZ_ALWAYS_INLINE JSNative JSObject::callHook() const {
 596   return getClass()->getCall();
 597 }
 598
 599 MOZ_ALWAYS_INLINE JSNative JSObject::constructHook() const {
 600   return getClass()->getConstruct();
 601 }
 602
 603 #endif /* vm_JSObject_inl_h */