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| -rw-r--r-- | dom/bindings/BindingUtils.h | 3267 |
1 files changed, 3267 insertions, 0 deletions
diff --git a/dom/bindings/BindingUtils.h b/dom/bindings/BindingUtils.h new file mode 100644 index 0000000000..fa1002af1c --- /dev/null +++ b/dom/bindings/BindingUtils.h @@ -0,0 +1,3267 @@ +/* -*- 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/. */ + +#ifndef mozilla_dom_BindingUtils_h__ +#define mozilla_dom_BindingUtils_h__ + +#include <type_traits> + +#include "jsfriendapi.h" +#include "js/CharacterEncoding.h" +#include "js/Conversions.h" +#include "js/experimental/JitInfo.h" // JSJitGetterOp, JSJitInfo +#include "js/friend/WindowProxy.h" // js::IsWindow, js::IsWindowProxy, js::ToWindowProxyIfWindow +#include "js/MemoryFunctions.h" +#include "js/Object.h" // JS::GetClass, JS::GetCompartment, JS::GetReservedSlot, JS::SetReservedSlot +#include "js/RealmOptions.h" +#include "js/String.h" // JS::GetLatin1LinearStringChars, JS::GetTwoByteLinearStringChars, JS::GetLinearStringLength, JS::LinearStringHasLatin1Chars, JS::StringHasLatin1Chars +#include "js/Wrapper.h" +#include "js/Zone.h" +#include "mozilla/ArrayUtils.h" +#include "mozilla/Array.h" +#include "mozilla/Assertions.h" +#include "mozilla/DeferredFinalize.h" +#include "mozilla/UniquePtr.h" +#include "mozilla/dom/BindingCallContext.h" +#include "mozilla/dom/BindingDeclarations.h" +#include "mozilla/dom/DOMJSClass.h" +#include "mozilla/dom/DOMJSProxyHandler.h" +#include "mozilla/dom/JSSlots.h" +#include "mozilla/dom/NonRefcountedDOMObject.h" +#include "mozilla/dom/Nullable.h" +#include "mozilla/dom/PrototypeList.h" +#include "mozilla/dom/RemoteObjectProxy.h" +#include "mozilla/SegmentedVector.h" +#include "mozilla/ErrorResult.h" +#include "mozilla/Likely.h" +#include "mozilla/MemoryReporting.h" +#include "nsIGlobalObject.h" +#include "nsJSUtils.h" +#include "nsISupportsImpl.h" +#include "xpcObjectHelper.h" +#include "xpcpublic.h" +#include "nsIVariant.h" +#include "mozilla/dom/FakeString.h" + +#include "nsWrapperCacheInlines.h" + +class nsGlobalWindowInner; +class nsGlobalWindowOuter; +class nsIInterfaceRequestor; + +namespace mozilla { + +enum UseCounter : int16_t; +enum class UseCounterWorker : int16_t; + +namespace dom { +class CustomElementReactionsStack; +class Document; +class EventTarget; +class MessageManagerGlobal; +class ObservableArrayProxyHandler; +class DedicatedWorkerGlobalScope; +template <typename KeyType, typename ValueType> +class Record; +class WindowProxyHolder; + +enum class DeprecatedOperations : uint16_t; + +nsresult UnwrapArgImpl(JSContext* cx, JS::Handle<JSObject*> src, + const nsIID& iid, void** ppArg); + +/** Convert a jsval to an XPCOM pointer. Caller must not assume that src will + keep the XPCOM pointer rooted. */ +template <class Interface> +inline nsresult UnwrapArg(JSContext* cx, JS::Handle<JSObject*> src, + Interface** ppArg) { + return UnwrapArgImpl(cx, src, NS_GET_TEMPLATE_IID(Interface), + reinterpret_cast<void**>(ppArg)); +} + +nsresult UnwrapWindowProxyArg(JSContext* cx, JS::Handle<JSObject*> src, + WindowProxyHolder& ppArg); + +// Returns true if the JSClass is used for DOM objects. +inline bool IsDOMClass(const JSClass* clasp) { + return clasp->flags & JSCLASS_IS_DOMJSCLASS; +} + +// Return true if the JSClass is used for non-proxy DOM objects. +inline bool IsNonProxyDOMClass(const JSClass* clasp) { + return IsDOMClass(clasp) && clasp->isNativeObject(); +} + +// Returns true if the JSClass is used for DOM interface and interface +// prototype objects. +inline bool IsDOMIfaceAndProtoClass(const JSClass* clasp) { + return clasp->flags & JSCLASS_IS_DOMIFACEANDPROTOJSCLASS; +} + +static_assert(DOM_OBJECT_SLOT == 0, + "DOM_OBJECT_SLOT doesn't match the proxy private slot. " + "Expect bad things"); +template <class T> +inline T* UnwrapDOMObject(JSObject* obj) { + MOZ_ASSERT(IsDOMClass(JS::GetClass(obj)), + "Don't pass non-DOM objects to this function"); + + JS::Value val = JS::GetReservedSlot(obj, DOM_OBJECT_SLOT); + return static_cast<T*>(val.toPrivate()); +} + +template <class T> +inline T* UnwrapPossiblyNotInitializedDOMObject(JSObject* obj) { + // This is used by the OjectMoved JSClass hook which can be called before + // JS_NewObject has returned and so before we have a chance to set + // DOM_OBJECT_SLOT to anything useful. + + MOZ_ASSERT(IsDOMClass(JS::GetClass(obj)), + "Don't pass non-DOM objects to this function"); + + JS::Value val = JS::GetReservedSlot(obj, DOM_OBJECT_SLOT); + if (val.isUndefined()) { + return nullptr; + } + return static_cast<T*>(val.toPrivate()); +} + +inline const DOMJSClass* GetDOMClass(const JSClass* clasp) { + return IsDOMClass(clasp) ? DOMJSClass::FromJSClass(clasp) : nullptr; +} + +inline const DOMJSClass* GetDOMClass(JSObject* obj) { + return GetDOMClass(JS::GetClass(obj)); +} + +inline nsISupports* UnwrapDOMObjectToISupports(JSObject* aObject) { + const DOMJSClass* clasp = GetDOMClass(aObject); + if (!clasp || !clasp->mDOMObjectIsISupports) { + return nullptr; + } + + return UnwrapPossiblyNotInitializedDOMObject<nsISupports>(aObject); +} + +inline bool IsDOMObject(JSObject* obj) { return IsDOMClass(JS::GetClass(obj)); } + +// There are two valid ways to use UNWRAP_OBJECT: Either obj needs to +// be a MutableHandle<JSObject*>, or value needs to be a strong-reference +// smart pointer type (OwningNonNull or RefPtr or nsCOMPtr), in which case obj +// can be anything that converts to JSObject*. +// +// This can't be used with Window, EventTarget, or Location as the "Interface" +// argument (and will fail a static_assert if you try to do that). Use +// UNWRAP_MAYBE_CROSS_ORIGIN_OBJECT to unwrap to those interfaces. +#define UNWRAP_OBJECT(Interface, obj, value) \ + mozilla::dom::binding_detail::UnwrapObjectWithCrossOriginAsserts< \ + mozilla::dom::prototypes::id::Interface, \ + mozilla::dom::Interface##_Binding::NativeType>(obj, value) + +// UNWRAP_MAYBE_CROSS_ORIGIN_OBJECT is just like UNWRAP_OBJECT but requires a +// JSContext in a Realm that represents "who is doing the unwrapping?" to +// properly unwrap the object. +#define UNWRAP_MAYBE_CROSS_ORIGIN_OBJECT(Interface, obj, value, cx) \ + mozilla::dom::UnwrapObject<mozilla::dom::prototypes::id::Interface, \ + mozilla::dom::Interface##_Binding::NativeType>( \ + obj, value, cx) + +// Test whether the given object is an instance of the given interface. +#define IS_INSTANCE_OF(Interface, obj) \ + mozilla::dom::IsInstanceOf<mozilla::dom::prototypes::id::Interface, \ + mozilla::dom::Interface##_Binding::NativeType>( \ + obj) + +// Unwrap the given non-wrapper object. This can be used with any obj that +// converts to JSObject*; as long as that JSObject* is live the return value +// will be valid. +#define UNWRAP_NON_WRAPPER_OBJECT(Interface, obj, value) \ + mozilla::dom::UnwrapNonWrapperObject< \ + mozilla::dom::prototypes::id::Interface, \ + mozilla::dom::Interface##_Binding::NativeType>(obj, value) + +// Some callers don't want to set an exception when unwrapping fails +// (for example, overload resolution uses unwrapping to tell what sort +// of thing it's looking at). +// U must be something that a T* can be assigned to (e.g. T* or an RefPtr<T>). +// +// The obj argument will be mutated to point to CheckedUnwrap of itself if the +// passed-in value is not a DOM object and CheckedUnwrap succeeds. +// +// If mayBeWrapper is true, there are three valid ways to invoke +// UnwrapObjectInternal: Either obj needs to be a class wrapping a +// MutableHandle<JSObject*>, with an assignment operator that sets the handle to +// the given object, or U needs to be a strong-reference smart pointer type +// (OwningNonNull or RefPtr or nsCOMPtr), or the value being stored in "value" +// must not escape past being tested for falsiness immediately after the +// UnwrapObjectInternal call. +// +// If mayBeWrapper is false, obj can just be a JSObject*, and U anything that a +// T* can be assigned to. +// +// The cx arg is in practice allowed to be either nullptr or JSContext* or a +// BindingCallContext reference. If it's nullptr we will do a +// CheckedUnwrapStatic and it's the caller's responsibility to make sure they're +// not trying to work with Window or Location objects. Otherwise we'll do a +// CheckedUnwrapDynamic. This all only matters if mayBeWrapper is true; if it's +// false just pass nullptr for the cx arg. +namespace binding_detail { +template <class T, bool mayBeWrapper, typename U, typename V, typename CxType> +MOZ_ALWAYS_INLINE nsresult UnwrapObjectInternal(V& obj, U& value, + prototypes::ID protoID, + uint32_t protoDepth, + const CxType& cx) { + static_assert(std::is_same_v<CxType, JSContext*> || + std::is_same_v<CxType, BindingCallContext> || + std::is_same_v<CxType, decltype(nullptr)>, + "Unexpected CxType"); + + /* First check to see whether we have a DOM object */ + const DOMJSClass* domClass = GetDOMClass(obj); + if (domClass) { + /* This object is a DOM object. Double-check that it is safely + castable to T by checking whether it claims to inherit from the + class identified by protoID. */ + if (domClass->mInterfaceChain[protoDepth] == protoID) { + value = UnwrapDOMObject<T>(obj); + return NS_OK; + } + } + + /* Maybe we have a security wrapper or outer window? */ + if (!mayBeWrapper || !js::IsWrapper(obj)) { + // For non-cross-origin-accessible methods and properties, remote object + // proxies should behave the same as opaque wrappers. + if (IsRemoteObjectProxy(obj)) { + return NS_ERROR_XPC_SECURITY_MANAGER_VETO; + } + + /* Not a DOM object, not a wrapper, just bail */ + return NS_ERROR_XPC_BAD_CONVERT_JS; + } + + JSObject* unwrappedObj; + if (std::is_same_v<CxType, decltype(nullptr)>) { + unwrappedObj = js::CheckedUnwrapStatic(obj); + } else { + unwrappedObj = + js::CheckedUnwrapDynamic(obj, cx, /* stopAtWindowProxy = */ false); + } + if (!unwrappedObj) { + return NS_ERROR_XPC_SECURITY_MANAGER_VETO; + } + + if (std::is_same_v<CxType, decltype(nullptr)>) { + // We might still have a windowproxy here. But it shouldn't matter, because + // that's not what the caller is looking for, so we're going to fail out + // anyway below once we do the recursive call to ourselves with wrapper + // unwrapping disabled. + MOZ_ASSERT(!js::IsWrapper(unwrappedObj) || js::IsWindowProxy(unwrappedObj)); + } else { + // We shouldn't have a wrapper by now. + MOZ_ASSERT(!js::IsWrapper(unwrappedObj)); + } + + // Recursive call is OK, because now we're using false for mayBeWrapper and + // we never reach this code if that boolean is false, so can't keep calling + // ourselves. + // + // Unwrap into a temporary pointer, because in general unwrapping into + // something of type U might trigger GC (e.g. release the value currently + // stored in there, with arbitrary consequences) and invalidate the + // "unwrappedObj" pointer. + T* tempValue = nullptr; + nsresult rv = UnwrapObjectInternal<T, false>(unwrappedObj, tempValue, protoID, + protoDepth, nullptr); + if (NS_SUCCEEDED(rv)) { + // Suppress a hazard related to keeping tempValue alive across + // UnwrapObjectInternal, because the analysis can't tell that this function + // will not GC if maybeWrapped=False and we've already gone through a level + // of unwrapping so unwrappedObj will be !IsWrapper. + JS::AutoSuppressGCAnalysis suppress; + + // It's very important to not update "obj" with the "unwrappedObj" value + // until we know the unwrap has succeeded. Otherwise, in a situation in + // which we have an overload of object and primitive we could end up + // converting to the primitive from the unwrappedObj, whereas we want to do + // it from the original object. + obj = unwrappedObj; + // And now assign to "value"; at this point we don't care if a GC happens + // and invalidates unwrappedObj. + value = tempValue; + return NS_OK; + } + + /* It's the wrong sort of DOM object */ + return NS_ERROR_XPC_BAD_CONVERT_JS; +} + +struct MutableObjectHandleWrapper { + explicit MutableObjectHandleWrapper(JS::MutableHandle<JSObject*> aHandle) + : mHandle(aHandle) {} + + void operator=(JSObject* aObject) { + MOZ_ASSERT(aObject); + mHandle.set(aObject); + } + + operator JSObject*() const { return mHandle; } + + private: + JS::MutableHandle<JSObject*> mHandle; +}; + +struct MutableValueHandleWrapper { + explicit MutableValueHandleWrapper(JS::MutableHandle<JS::Value> aHandle) + : mHandle(aHandle) {} + + void operator=(JSObject* aObject) { + MOZ_ASSERT(aObject); +#ifdef ENABLE_RECORD_TUPLE + MOZ_ASSERT(!js::gc::MaybeForwardedIsExtendedPrimitive(*aObject)); +#endif + mHandle.setObject(*aObject); + } + + operator JSObject*() const { return &mHandle.toObject(); } + + private: + JS::MutableHandle<JS::Value> mHandle; +}; + +} // namespace binding_detail + +// UnwrapObject overloads that ensure we have a MutableHandle to keep it alive. +template <prototypes::ID PrototypeID, class T, typename U, typename CxType> +MOZ_ALWAYS_INLINE nsresult UnwrapObject(JS::MutableHandle<JSObject*> obj, + U& value, const CxType& cx) { + binding_detail::MutableObjectHandleWrapper wrapper(obj); + return binding_detail::UnwrapObjectInternal<T, true>( + wrapper, value, PrototypeID, PrototypeTraits<PrototypeID>::Depth, cx); +} + +template <prototypes::ID PrototypeID, class T, typename U, typename CxType> +MOZ_ALWAYS_INLINE nsresult UnwrapObject(JS::MutableHandle<JS::Value> obj, + U& value, const CxType& cx) { + MOZ_ASSERT(obj.isObject()); + binding_detail::MutableValueHandleWrapper wrapper(obj); + return binding_detail::UnwrapObjectInternal<T, true>( + wrapper, value, PrototypeID, PrototypeTraits<PrototypeID>::Depth, cx); +} + +// UnwrapObject overloads that ensure we have a strong ref to keep it alive. +template <prototypes::ID PrototypeID, class T, typename U, typename CxType> +MOZ_ALWAYS_INLINE nsresult UnwrapObject(JSObject* obj, RefPtr<U>& value, + const CxType& cx) { + return binding_detail::UnwrapObjectInternal<T, true>( + obj, value, PrototypeID, PrototypeTraits<PrototypeID>::Depth, cx); +} + +template <prototypes::ID PrototypeID, class T, typename U, typename CxType> +MOZ_ALWAYS_INLINE nsresult UnwrapObject(JSObject* obj, nsCOMPtr<U>& value, + const CxType& cx) { + return binding_detail::UnwrapObjectInternal<T, true>( + obj, value, PrototypeID, PrototypeTraits<PrototypeID>::Depth, cx); +} + +template <prototypes::ID PrototypeID, class T, typename U, typename CxType> +MOZ_ALWAYS_INLINE nsresult UnwrapObject(JSObject* obj, OwningNonNull<U>& value, + const CxType& cx) { + return binding_detail::UnwrapObjectInternal<T, true>( + obj, value, PrototypeID, PrototypeTraits<PrototypeID>::Depth, cx); +} + +template <prototypes::ID PrototypeID, class T, typename U, typename CxType> +MOZ_ALWAYS_INLINE nsresult UnwrapObject(JSObject* obj, NonNull<U>& value, + const CxType& cx) { + return binding_detail::UnwrapObjectInternal<T, true>( + obj, value, PrototypeID, PrototypeTraits<PrototypeID>::Depth, cx); +} + +// An UnwrapObject overload that just calls one of the JSObject* ones. +template <prototypes::ID PrototypeID, class T, typename U, typename CxType> +MOZ_ALWAYS_INLINE nsresult UnwrapObject(JS::Handle<JS::Value> obj, U& value, + const CxType& cx) { + MOZ_ASSERT(obj.isObject()); + return UnwrapObject<PrototypeID, T>(&obj.toObject(), value, cx); +} + +template <prototypes::ID PrototypeID, class T, typename U, typename CxType> +MOZ_ALWAYS_INLINE nsresult UnwrapObject(JS::Handle<JS::Value> obj, + NonNull<U>& value, const CxType& cx) { + MOZ_ASSERT(obj.isObject()); + return UnwrapObject<PrototypeID, T>(&obj.toObject(), value, cx); +} + +template <prototypes::ID PrototypeID> +MOZ_ALWAYS_INLINE void AssertStaticUnwrapOK() { + static_assert(PrototypeID != prototypes::id::Window, + "Can't do static unwrap of WindowProxy; use " + "UNWRAP_MAYBE_CROSS_ORIGIN_OBJECT or a cross-origin-object " + "aware version of IS_INSTANCE_OF"); + static_assert(PrototypeID != prototypes::id::EventTarget, + "Can't do static unwrap of WindowProxy (which an EventTarget " + "might be); use UNWRAP_MAYBE_CROSS_ORIGIN_OBJECT or a " + "cross-origin-object aware version of IS_INSTANCE_OF"); + static_assert(PrototypeID != prototypes::id::Location, + "Can't do static unwrap of Location; use " + "UNWRAP_MAYBE_CROSS_ORIGIN_OBJECT or a cross-origin-object " + "aware version of IS_INSTANCE_OF"); +} + +namespace binding_detail { +// This function is just here so we can do some static asserts in a centralized +// place instead of putting them in every single UnwrapObject overload. +template <prototypes::ID PrototypeID, class T, typename U, typename V> +MOZ_ALWAYS_INLINE nsresult UnwrapObjectWithCrossOriginAsserts(V&& obj, + U& value) { + AssertStaticUnwrapOK<PrototypeID>(); + return UnwrapObject<PrototypeID, T>(obj, value, nullptr); +} +} // namespace binding_detail + +template <prototypes::ID PrototypeID, class T> +MOZ_ALWAYS_INLINE bool IsInstanceOf(JSObject* obj) { + AssertStaticUnwrapOK<PrototypeID>(); + void* ignored; + nsresult unwrapped = binding_detail::UnwrapObjectInternal<T, true>( + obj, ignored, PrototypeID, PrototypeTraits<PrototypeID>::Depth, nullptr); + return NS_SUCCEEDED(unwrapped); +} + +template <prototypes::ID PrototypeID, class T, typename U> +MOZ_ALWAYS_INLINE nsresult UnwrapNonWrapperObject(JSObject* obj, U& value) { + MOZ_ASSERT(!js::IsWrapper(obj)); + return binding_detail::UnwrapObjectInternal<T, false>( + obj, value, PrototypeID, PrototypeTraits<PrototypeID>::Depth, nullptr); +} + +MOZ_ALWAYS_INLINE bool IsConvertibleToDictionary(JS::Handle<JS::Value> val) { + return val.isNullOrUndefined() || val.isObject(); +} + +// The items in the protoAndIfaceCache are indexed by the prototypes::id::ID, +// constructors::id::ID and namedpropertiesobjects::id::ID enums, in that order. +// The end of the prototype objects should be the start of the interface +// objects, and the end of the interface objects should be the start of the +// named properties objects. +static_assert((size_t)constructors::id::_ID_Start == + (size_t)prototypes::id::_ID_Count && + (size_t)namedpropertiesobjects::id::_ID_Start == + (size_t)constructors::id::_ID_Count, + "Overlapping or discontiguous indexes."); +const size_t kProtoAndIfaceCacheCount = namedpropertiesobjects::id::_ID_Count; + +class ProtoAndIfaceCache { + // The caching strategy we use depends on what sort of global we're dealing + // with. For a window-like global, we want everything to be as fast as + // possible, so we use a flat array, indexed by prototype/constructor ID. + // For everything else (e.g. globals for JSMs), space is more important than + // speed, so we use a two-level lookup table. + + class ArrayCache + : public Array<JS::Heap<JSObject*>, kProtoAndIfaceCacheCount> { + public: + bool HasEntryInSlot(size_t i) { + // Do an explicit call to the Heap<…> bool conversion operator. Because + // that operator is marked explicit we'd otherwise end up doing an + // implicit cast to JSObject* first, causing an unnecessary call to + // exposeToActiveJS(). + return bool((*this)[i]); + } + + JS::Heap<JSObject*>& EntrySlotOrCreate(size_t i) { return (*this)[i]; } + + JS::Heap<JSObject*>& EntrySlotMustExist(size_t i) { return (*this)[i]; } + + void Trace(JSTracer* aTracer) { + for (size_t i = 0; i < ArrayLength(*this); ++i) { + JS::TraceEdge(aTracer, &(*this)[i], "protoAndIfaceCache[i]"); + } + } + + size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) { + return aMallocSizeOf(this); + } + }; + + class PageTableCache { + public: + PageTableCache() { memset(mPages.begin(), 0, sizeof(mPages)); } + + ~PageTableCache() { + for (size_t i = 0; i < ArrayLength(mPages); ++i) { + delete mPages[i]; + } + } + + bool HasEntryInSlot(size_t i) { + MOZ_ASSERT(i < kProtoAndIfaceCacheCount); + size_t pageIndex = i / kPageSize; + size_t leafIndex = i % kPageSize; + Page* p = mPages[pageIndex]; + if (!p) { + return false; + } + // Do an explicit call to the Heap<…> bool conversion operator. Because + // that operator is marked explicit we'd otherwise end up doing an + // implicit cast to JSObject* first, causing an unnecessary call to + // exposeToActiveJS(). + return bool((*p)[leafIndex]); + } + + JS::Heap<JSObject*>& EntrySlotOrCreate(size_t i) { + MOZ_ASSERT(i < kProtoAndIfaceCacheCount); + size_t pageIndex = i / kPageSize; + size_t leafIndex = i % kPageSize; + Page* p = mPages[pageIndex]; + if (!p) { + p = new Page; + mPages[pageIndex] = p; + } + return (*p)[leafIndex]; + } + + JS::Heap<JSObject*>& EntrySlotMustExist(size_t i) { + MOZ_ASSERT(i < kProtoAndIfaceCacheCount); + size_t pageIndex = i / kPageSize; + size_t leafIndex = i % kPageSize; + Page* p = mPages[pageIndex]; + MOZ_ASSERT(p); + return (*p)[leafIndex]; + } + + void Trace(JSTracer* trc) { + for (size_t i = 0; i < ArrayLength(mPages); ++i) { + Page* p = mPages[i]; + if (p) { + for (size_t j = 0; j < ArrayLength(*p); ++j) { + JS::TraceEdge(trc, &(*p)[j], "protoAndIfaceCache[i]"); + } + } + } + } + + size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) { + size_t n = aMallocSizeOf(this); + for (size_t i = 0; i < ArrayLength(mPages); ++i) { + n += aMallocSizeOf(mPages[i]); + } + return n; + } + + private: + static const size_t kPageSize = 16; + typedef Array<JS::Heap<JSObject*>, kPageSize> Page; + static const size_t kNPages = + kProtoAndIfaceCacheCount / kPageSize + + size_t(bool(kProtoAndIfaceCacheCount % kPageSize)); + Array<Page*, kNPages> mPages; + }; + + public: + enum Kind { WindowLike, NonWindowLike }; + + explicit ProtoAndIfaceCache(Kind aKind) : mKind(aKind) { + MOZ_COUNT_CTOR(ProtoAndIfaceCache); + if (aKind == WindowLike) { + mArrayCache = new ArrayCache(); + } else { + mPageTableCache = new PageTableCache(); + } + } + + ~ProtoAndIfaceCache() { + if (mKind == WindowLike) { + delete mArrayCache; + } else { + delete mPageTableCache; + } + MOZ_COUNT_DTOR(ProtoAndIfaceCache); + } + +#define FORWARD_OPERATION(opName, args) \ + do { \ + if (mKind == WindowLike) { \ + return mArrayCache->opName args; \ + } else { \ + return mPageTableCache->opName args; \ + } \ + } while (0) + + // Return whether slot i contains an object. This doesn't return the object + // itself because in practice consumers just want to know whether it's there + // or not, and that doesn't require barriering, which returning the object + // pointer does. + bool HasEntryInSlot(size_t i) { FORWARD_OPERATION(HasEntryInSlot, (i)); } + + // Return a reference to slot i, creating it if necessary. There + // may not be an object in the returned slot. + JS::Heap<JSObject*>& EntrySlotOrCreate(size_t i) { + FORWARD_OPERATION(EntrySlotOrCreate, (i)); + } + + // Return a reference to slot i, which is guaranteed to already + // exist. There may not be an object in the slot, if prototype and + // constructor initialization for one of our bindings failed. + JS::Heap<JSObject*>& EntrySlotMustExist(size_t i) { + FORWARD_OPERATION(EntrySlotMustExist, (i)); + } + + void Trace(JSTracer* aTracer) { FORWARD_OPERATION(Trace, (aTracer)); } + + size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) { + size_t n = aMallocSizeOf(this); + n += (mKind == WindowLike + ? mArrayCache->SizeOfIncludingThis(aMallocSizeOf) + : mPageTableCache->SizeOfIncludingThis(aMallocSizeOf)); + return n; + } +#undef FORWARD_OPERATION + + private: + union { + ArrayCache* mArrayCache; + PageTableCache* mPageTableCache; + }; + Kind mKind; +}; + +inline void AllocateProtoAndIfaceCache(JSObject* obj, + ProtoAndIfaceCache::Kind aKind) { + MOZ_ASSERT(JS::GetClass(obj)->flags & JSCLASS_DOM_GLOBAL); + MOZ_ASSERT(JS::GetReservedSlot(obj, DOM_PROTOTYPE_SLOT).isUndefined()); + + ProtoAndIfaceCache* protoAndIfaceCache = new ProtoAndIfaceCache(aKind); + + JS::SetReservedSlot(obj, DOM_PROTOTYPE_SLOT, + JS::PrivateValue(protoAndIfaceCache)); +} + +#ifdef DEBUG +struct VerifyTraceProtoAndIfaceCacheCalledTracer : public JS::CallbackTracer { + bool ok; + + explicit VerifyTraceProtoAndIfaceCacheCalledTracer(JSContext* cx) + : JS::CallbackTracer(cx, JS::TracerKind::VerifyTraceProtoAndIface), + ok(false) {} + + void onChild(JS::GCCellPtr, const char* name) override { + // We don't do anything here, we only want to verify that + // TraceProtoAndIfaceCache was called. + } +}; +#endif + +inline void TraceProtoAndIfaceCache(JSTracer* trc, JSObject* obj) { + MOZ_ASSERT(JS::GetClass(obj)->flags & JSCLASS_DOM_GLOBAL); + +#ifdef DEBUG + if (trc->kind() == JS::TracerKind::VerifyTraceProtoAndIface) { + // We don't do anything here, we only want to verify that + // TraceProtoAndIfaceCache was called. + static_cast<VerifyTraceProtoAndIfaceCacheCalledTracer*>(trc)->ok = true; + return; + } +#endif + + if (!DOMGlobalHasProtoAndIFaceCache(obj)) return; + ProtoAndIfaceCache* protoAndIfaceCache = GetProtoAndIfaceCache(obj); + protoAndIfaceCache->Trace(trc); +} + +inline void DestroyProtoAndIfaceCache(JSObject* obj) { + MOZ_ASSERT(JS::GetClass(obj)->flags & JSCLASS_DOM_GLOBAL); + + if (!DOMGlobalHasProtoAndIFaceCache(obj)) { + return; + } + + ProtoAndIfaceCache* protoAndIfaceCache = GetProtoAndIfaceCache(obj); + + delete protoAndIfaceCache; +} + +/** + * Add constants to an object. + */ +bool DefineConstants(JSContext* cx, JS::Handle<JSObject*> obj, + const ConstantSpec* cs); + +struct JSNativeHolder { + JSNative mNative; + const NativePropertyHooks* mPropertyHooks; +}; + +struct LegacyFactoryFunction { + const char* mName; + const JSNativeHolder mHolder; + unsigned mNargs; +}; + +// clang-format off +/* + * Create a DOM interface object (if constructorClass is non-null) and/or a + * DOM interface prototype object (if protoClass is non-null). + * + * global is used as the parent of the interface object and the interface + * prototype object + * protoProto is the prototype to use for the interface prototype object. + * interfaceProto is the prototype to use for the interface object. This can be + * null if both constructorClass and constructor are null (as in, + * if we're not creating an interface object at all). + * protoClass is the JSClass to use for the interface prototype object. + * This is null if we should not create an interface prototype + * object. + * protoCache a pointer to a JSObject pointer where we should cache the + * interface prototype object. This must be null if protoClass is and + * vice versa. + * constructorClass is the JSClass to use for the interface object. + * This is null if we should not create an interface object or + * if it should be a function object. + * constructor holds the JSNative to back the interface object which should be a + * Function, unless constructorClass is non-null in which case it is + * ignored. If this is null and constructorClass is also null then + * we should not create an interface object at all. + * ctorNargs is the length of the constructor function; 0 if no constructor + * isConstructorChromeOnly if true, the constructor is ChromeOnly. + * constructorCache a pointer to a JSObject pointer where we should cache the + * interface object. This must be null if both constructorClass + * and constructor are null, and non-null otherwise. + * properties contains the methods, attributes and constants to be defined on + * objects in any compartment. + * chromeProperties contains the methods, attributes and constants to be defined + * on objects in chrome compartments. This must be null if the + * interface doesn't have any ChromeOnly properties or if the + * object is being created in non-chrome compartment. + * name the name to use for 1) the WebIDL class string, which is the value + * that's used for @@toStringTag, 2) the name property for interface + * objects and 3) the property on the global object that would be set to + * the interface object. In general this is the interface identifier. + * LegacyNamespace would expect something different for 1), but we don't + * support that. The class string for default iterator objects is not + * usable as 2) or 3), but default iterator objects don't have an interface + * object. + * defineOnGlobal controls whether properties should be defined on the given + * global for the interface object (if any) and named + * constructors (if any) for this interface. This can be + * false in situations where we want the properties to only + * appear on privileged Xrays but not on the unprivileged + * underlying global. + * unscopableNames if not null it points to a null-terminated list of const + * char* names of the unscopable properties for this interface. + * isGlobal if true, we're creating interface objects for a [Global] interface, + * and hence shouldn't define properties on the prototype object. + * legacyWindowAliases if not null it points to a null-terminated list of const + * char* names of the legacy window aliases for this + * interface. + * + * At least one of protoClass, constructorClass or constructor should be + * non-null. If constructorClass or constructor are non-null, the resulting + * interface object will be defined on the given global with property name + * |name|, which must also be non-null. + */ +// clang-format on +void CreateInterfaceObjects( + JSContext* cx, JS::Handle<JSObject*> global, + JS::Handle<JSObject*> protoProto, const JSClass* protoClass, + JS::Heap<JSObject*>* protoCache, JS::Handle<JSObject*> constructorProto, + const JSClass* constructorClass, unsigned ctorNargs, + bool isConstructorChromeOnly, + const LegacyFactoryFunction* namedConstructors, + JS::Heap<JSObject*>* constructorCache, const NativeProperties* properties, + const NativeProperties* chromeOnlyProperties, const char* name, + bool defineOnGlobal, const char* const* unscopableNames, bool isGlobal, + const char* const* legacyWindowAliases, bool isNamespace); + +/** + * Define the properties (regular and chrome-only) on obj. + * + * obj the object to install the properties on. This should be the interface + * prototype object for regular interfaces and the instance object for + * interfaces marked with Global. + * properties contains the methods, attributes and constants to be defined on + * objects in any compartment. + * chromeProperties contains the methods, attributes and constants to be defined + * on objects in chrome compartments. This must be null if the + * interface doesn't have any ChromeOnly properties or if the + * object is being created in non-chrome compartment. + */ +bool DefineProperties(JSContext* cx, JS::Handle<JSObject*> obj, + const NativeProperties* properties, + const NativeProperties* chromeOnlyProperties); + +/* + * Define the legacy unforgeable methods on an object. + */ +bool DefineLegacyUnforgeableMethods( + JSContext* cx, JS::Handle<JSObject*> obj, + const Prefable<const JSFunctionSpec>* props); + +/* + * Define the legacy unforgeable attributes on an object. + */ +bool DefineLegacyUnforgeableAttributes( + JSContext* cx, JS::Handle<JSObject*> obj, + const Prefable<const JSPropertySpec>* props); + +#define HAS_MEMBER_TYPEDEFS \ + private: \ + typedef char yes[1]; \ + typedef char no[2] + +#ifdef _MSC_VER +# define HAS_MEMBER_CHECK(_name) \ + template <typename V> \ + static yes& Check##_name(char(*)[(&V::_name == 0) + 1]) +#else +# define HAS_MEMBER_CHECK(_name) \ + template <typename V> \ + static yes& Check##_name(char(*)[sizeof(&V::_name) + 1]) +#endif + +#define HAS_MEMBER(_memberName, _valueName) \ + private: \ + HAS_MEMBER_CHECK(_memberName); \ + template <typename V> \ + static no& Check##_memberName(...); \ + \ + public: \ + static bool const _valueName = \ + sizeof(Check##_memberName<T>(nullptr)) == sizeof(yes) + +template <class T> +struct NativeHasMember { + HAS_MEMBER_TYPEDEFS; + + HAS_MEMBER(GetParentObject, GetParentObject); + HAS_MEMBER(WrapObject, WrapObject); +}; + +template <class T> +struct IsSmartPtr { + HAS_MEMBER_TYPEDEFS; + + HAS_MEMBER(get, value); +}; + +template <class T> +struct IsRefcounted { + HAS_MEMBER_TYPEDEFS; + + HAS_MEMBER(AddRef, HasAddref); + HAS_MEMBER(Release, HasRelease); + + public: + static bool const value = HasAddref && HasRelease; + + private: + // This struct only works if T is fully declared (not just forward declared). + // The std::is_base_of check will ensure that, we don't really need it for any + // other reason (the static assert will of course always be true). + static_assert(!std::is_base_of<nsISupports, T>::value || IsRefcounted::value, + "Classes derived from nsISupports are refcounted!"); +}; + +#undef HAS_MEMBER +#undef HAS_MEMBER_CHECK +#undef HAS_MEMBER_TYPEDEFS + +#ifdef DEBUG +template <class T, bool isISupports = std::is_base_of<nsISupports, T>::value> +struct CheckWrapperCacheCast { + static bool Check() { + return reinterpret_cast<uintptr_t>( + static_cast<nsWrapperCache*>(reinterpret_cast<T*>(1))) == 1; + } +}; +template <class T> +struct CheckWrapperCacheCast<T, true> { + static bool Check() { return true; } +}; +#endif + +inline bool TryToOuterize(JS::MutableHandle<JS::Value> rval) { +#ifdef ENABLE_RECORD_TUPLE + if (rval.isExtendedPrimitive()) { + return true; + } +#endif + MOZ_ASSERT(rval.isObject()); + if (js::IsWindow(&rval.toObject())) { + JSObject* obj = js::ToWindowProxyIfWindow(&rval.toObject()); + MOZ_ASSERT(obj); + rval.set(JS::ObjectValue(*obj)); + } + + return true; +} + +inline bool TryToOuterize(JS::MutableHandle<JSObject*> obj) { + if (js::IsWindow(obj)) { + JSObject* proxy = js::ToWindowProxyIfWindow(obj); + MOZ_ASSERT(proxy); + obj.set(proxy); + } + + return true; +} + +// Make sure to wrap the given string value into the right compartment, as +// needed. +MOZ_ALWAYS_INLINE +bool MaybeWrapStringValue(JSContext* cx, JS::MutableHandle<JS::Value> rval) { + MOZ_ASSERT(rval.isString()); + JSString* str = rval.toString(); + if (JS::GetStringZone(str) != js::GetContextZone(cx)) { + return JS_WrapValue(cx, rval); + } + return true; +} + +// Make sure to wrap the given object value into the right compartment as +// needed. This will work correctly, but possibly slowly, on all objects. +MOZ_ALWAYS_INLINE +bool MaybeWrapObjectValue(JSContext* cx, JS::MutableHandle<JS::Value> rval) { + MOZ_ASSERT(rval.hasObjectPayload()); + + // Cross-compartment always requires wrapping. + JSObject* obj = &rval.getObjectPayload(); + if (JS::GetCompartment(obj) != js::GetContextCompartment(cx)) { + return JS_WrapValue(cx, rval); + } + + // We're same-compartment, but we might still need to outerize if we + // have a Window. + return TryToOuterize(rval); +} + +// Like MaybeWrapObjectValue, but working with a +// JS::MutableHandle<JSObject*> which must be non-null. +MOZ_ALWAYS_INLINE +bool MaybeWrapObject(JSContext* cx, JS::MutableHandle<JSObject*> obj) { + if (JS::GetCompartment(obj) != js::GetContextCompartment(cx)) { + return JS_WrapObject(cx, obj); + } + + // We're same-compartment, but we might still need to outerize if we + // have a Window. + return TryToOuterize(obj); +} + +// Like MaybeWrapObjectValue, but also allows null +MOZ_ALWAYS_INLINE +bool MaybeWrapObjectOrNullValue(JSContext* cx, + JS::MutableHandle<JS::Value> rval) { + MOZ_ASSERT(rval.isObjectOrNull()); + if (rval.isNull()) { + return true; + } + return MaybeWrapObjectValue(cx, rval); +} + +// Wrapping for objects that are known to not be DOM objects +MOZ_ALWAYS_INLINE +bool MaybeWrapNonDOMObjectValue(JSContext* cx, + JS::MutableHandle<JS::Value> rval) { + MOZ_ASSERT(rval.isObject()); + // Compared to MaybeWrapObjectValue we just skip the TryToOuterize call. The + // only reason it would be needed is if we have a Window object, which would + // have a DOM class. Assert that we don't have any DOM-class objects coming + // through here. + MOZ_ASSERT(!GetDOMClass(&rval.toObject())); + + JSObject* obj = &rval.toObject(); + if (JS::GetCompartment(obj) == js::GetContextCompartment(cx)) { + return true; + } + return JS_WrapValue(cx, rval); +} + +// Like MaybeWrapNonDOMObjectValue but allows null +MOZ_ALWAYS_INLINE +bool MaybeWrapNonDOMObjectOrNullValue(JSContext* cx, + JS::MutableHandle<JS::Value> rval) { + MOZ_ASSERT(rval.isObjectOrNull()); + if (rval.isNull()) { + return true; + } + return MaybeWrapNonDOMObjectValue(cx, rval); +} + +// If rval is a gcthing and is not in the compartment of cx, wrap rval +// into the compartment of cx (typically by replacing it with an Xray or +// cross-compartment wrapper around the original object). +MOZ_ALWAYS_INLINE bool MaybeWrapValue(JSContext* cx, + JS::MutableHandle<JS::Value> rval) { + if (rval.isGCThing()) { + if (rval.isString()) { + return MaybeWrapStringValue(cx, rval); + } + if (rval.hasObjectPayload()) { + return MaybeWrapObjectValue(cx, rval); + } + // This could be optimized by checking the zone first, similar to + // the way strings are handled. At present, this is used primarily + // for structured cloning, so avoiding the overhead of JS_WrapValue + // calls is less important than for other types. + if (rval.isBigInt()) { + return JS_WrapValue(cx, rval); + } + MOZ_ASSERT(rval.isSymbol()); + JS_MarkCrossZoneId(cx, JS::PropertyKey::Symbol(rval.toSymbol())); + } + return true; +} + +namespace binding_detail { +enum GetOrCreateReflectorWrapBehavior { + eWrapIntoContextCompartment, + eDontWrapIntoContextCompartment +}; + +template <class T> +struct TypeNeedsOuterization { + // We only need to outerize Window objects, so anything inheriting from + // nsGlobalWindow (which inherits from EventTarget itself). + static const bool value = std::is_base_of<nsGlobalWindowInner, T>::value || + std::is_base_of<nsGlobalWindowOuter, T>::value || + std::is_same_v<EventTarget, T>; +}; + +#ifdef DEBUG +template <typename T, bool isISupports = std::is_base_of<nsISupports, T>::value> +struct CheckWrapperCacheTracing { + static inline void Check(T* aObject) {} +}; + +template <typename T> +struct CheckWrapperCacheTracing<T, true> { + static void Check(T* aObject) { + // Rooting analysis thinks QueryInterface may GC, but we're dealing with + // a subset of QueryInterface, C++ only types here. + JS::AutoSuppressGCAnalysis nogc; + + nsWrapperCache* wrapperCacheFromQI = nullptr; + aObject->QueryInterface(NS_GET_IID(nsWrapperCache), + reinterpret_cast<void**>(&wrapperCacheFromQI)); + + MOZ_ASSERT(wrapperCacheFromQI, + "Missing nsWrapperCache from QueryInterface implementation?"); + + if (!wrapperCacheFromQI->GetWrapperPreserveColor()) { + // Can't assert that we trace the wrapper, since we don't have any + // wrapper to trace. + return; + } + + nsISupports* ccISupports = nullptr; + aObject->QueryInterface(NS_GET_IID(nsCycleCollectionISupports), + reinterpret_cast<void**>(&ccISupports)); + MOZ_ASSERT(ccISupports, + "nsWrapperCache object which isn't cycle collectable?"); + + nsXPCOMCycleCollectionParticipant* participant = nullptr; + CallQueryInterface(ccISupports, &participant); + MOZ_ASSERT(participant, "Can't QI to CycleCollectionParticipant?"); + + wrapperCacheFromQI->CheckCCWrapperTraversal(ccISupports, participant); + } +}; + +void AssertReflectorHasGivenProto(JSContext* aCx, JSObject* aReflector, + JS::Handle<JSObject*> aGivenProto); +#endif // DEBUG + +template <class T, GetOrCreateReflectorWrapBehavior wrapBehavior> +MOZ_ALWAYS_INLINE bool DoGetOrCreateDOMReflector( + JSContext* cx, T* value, JS::Handle<JSObject*> givenProto, + JS::MutableHandle<JS::Value> rval) { + MOZ_ASSERT(value); + MOZ_ASSERT_IF(givenProto, js::IsObjectInContextCompartment(givenProto, cx)); + JSObject* obj = value->GetWrapper(); + if (obj) { +#ifdef DEBUG + AssertReflectorHasGivenProto(cx, obj, givenProto); + // Have to reget obj because AssertReflectorHasGivenProto can + // trigger gc so the pointer may now be invalid. + obj = value->GetWrapper(); +#endif + } else { + obj = value->WrapObject(cx, givenProto); + if (!obj) { + // At this point, obj is null, so just return false. + // Callers seem to be testing JS_IsExceptionPending(cx) to + // figure out whether WrapObject() threw. + return false; + } + +#ifdef DEBUG + if (std::is_base_of<nsWrapperCache, T>::value) { + CheckWrapperCacheTracing<T>::Check(value); + } +#endif + } + +#ifdef DEBUG + const DOMJSClass* clasp = GetDOMClass(obj); + // clasp can be null if the cache contained a non-DOM object. + if (clasp) { + // Some sanity asserts about our object. Specifically: + // 1) If our class claims we're nsISupports, we better be nsISupports + // XXXbz ideally, we could assert that reinterpret_cast to nsISupports + // does the right thing, but I don't see a way to do it. :( + // 2) If our class doesn't claim we're nsISupports we better be + // reinterpret_castable to nsWrapperCache. + MOZ_ASSERT(clasp, "What happened here?"); + MOZ_ASSERT_IF(clasp->mDOMObjectIsISupports, + (std::is_base_of<nsISupports, T>::value)); + MOZ_ASSERT(CheckWrapperCacheCast<T>::Check()); + } +#endif + +#ifdef ENABLE_RECORD_TUPLE + MOZ_ASSERT(!js::gc::MaybeForwardedIsExtendedPrimitive(*obj)); +#endif + rval.set(JS::ObjectValue(*obj)); + + if (JS::GetCompartment(obj) == js::GetContextCompartment(cx)) { + return TypeNeedsOuterization<T>::value ? TryToOuterize(rval) : true; + } + + if (wrapBehavior == eDontWrapIntoContextCompartment) { + if (TypeNeedsOuterization<T>::value) { + JSAutoRealm ar(cx, obj); + return TryToOuterize(rval); + } + + return true; + } + + return JS_WrapValue(cx, rval); +} + +} // namespace binding_detail + +// Create a JSObject wrapping "value", if there isn't one already, and store it +// in rval. "value" must be a concrete class that implements a +// GetWrapperPreserveColor() which can return its existing wrapper, if any, and +// a WrapObject() which will try to create a wrapper. Typically, this is done by +// having "value" inherit from nsWrapperCache. +// +// The value stored in rval will be ready to be exposed to whatever JS +// is running on cx right now. In particular, it will be in the +// compartment of cx, and outerized as needed. +template <class T> +MOZ_ALWAYS_INLINE bool GetOrCreateDOMReflector( + JSContext* cx, T* value, JS::MutableHandle<JS::Value> rval, + JS::Handle<JSObject*> givenProto = nullptr) { + using namespace binding_detail; + return DoGetOrCreateDOMReflector<T, eWrapIntoContextCompartment>( + cx, value, givenProto, rval); +} + +// Like GetOrCreateDOMReflector but doesn't wrap into the context compartment, +// and hence does not actually require cx to be in a compartment. +template <class T> +MOZ_ALWAYS_INLINE bool GetOrCreateDOMReflectorNoWrap( + JSContext* cx, T* value, JS::MutableHandle<JS::Value> rval) { + using namespace binding_detail; + return DoGetOrCreateDOMReflector<T, eDontWrapIntoContextCompartment>( + cx, value, nullptr, rval); +} + +// Helper for different overloadings of WrapNewBindingNonWrapperCachedObject() +inline bool FinishWrapping(JSContext* cx, JS::Handle<JSObject*> obj, + JS::MutableHandle<JS::Value> rval) { +#ifdef ENABLE_RECORD_TUPLE + // If calling an (object) value's WrapObject() method returned a record/tuple, + // then something is very wrong. + MOZ_ASSERT(!js::gc::MaybeForwardedIsExtendedPrimitive(*obj)); +#endif + + // We can end up here in all sorts of compartments, per comments in + // WrapNewBindingNonWrapperCachedObject(). Make sure to JS_WrapValue! + rval.set(JS::ObjectValue(*obj)); + return MaybeWrapObjectValue(cx, rval); +} + +// Create a JSObject wrapping "value", for cases when "value" is a +// non-wrapper-cached object using WebIDL bindings. "value" must implement a +// WrapObject() method taking a JSContext and a prototype (possibly null) and +// returning the resulting object via a MutableHandle<JSObject*> outparam. +template <class T> +inline bool WrapNewBindingNonWrapperCachedObject( + JSContext* cx, JS::Handle<JSObject*> scopeArg, T* value, + JS::MutableHandle<JS::Value> rval, + JS::Handle<JSObject*> givenProto = nullptr) { + static_assert(IsRefcounted<T>::value, "Don't pass owned classes in here."); + MOZ_ASSERT(value); + // We try to wrap in the realm of the underlying object of "scope" + JS::Rooted<JSObject*> obj(cx); + { + // scope for the JSAutoRealm so that we restore the realm + // before we call JS_WrapValue. + Maybe<JSAutoRealm> ar; + // Maybe<Handle> doesn't so much work, and in any case, adding + // more Maybe (one for a Rooted and one for a Handle) adds more + // code (and branches!) than just adding a single rooted. + JS::Rooted<JSObject*> scope(cx, scopeArg); + JS::Rooted<JSObject*> proto(cx, givenProto); + if (js::IsWrapper(scope)) { + // We are working in the Realm of cx and will be producing our reflector + // there, so we need to succeed if that realm has access to the scope. + scope = + js::CheckedUnwrapDynamic(scope, cx, /* stopAtWindowProxy = */ false); + if (!scope) return false; + ar.emplace(cx, scope); + if (!JS_WrapObject(cx, &proto)) { + return false; + } + } else { + // cx and scope are same-compartment, but they might still be + // different-Realm. Enter the Realm of scope, since that's + // where we want to create our object. + ar.emplace(cx, scope); + } + + MOZ_ASSERT_IF(proto, js::IsObjectInContextCompartment(proto, cx)); + MOZ_ASSERT(js::IsObjectInContextCompartment(scope, cx)); + if (!value->WrapObject(cx, proto, &obj)) { + return false; + } + } + + return FinishWrapping(cx, obj, rval); +} + +// Create a JSObject wrapping "value", for cases when "value" is a +// non-wrapper-cached owned object using WebIDL bindings. "value" must +// implement a WrapObject() method taking a taking a JSContext and a prototype +// (possibly null) and returning two pieces of information: the resulting object +// via a MutableHandle<JSObject*> outparam and a boolean return value that is +// true if the JSObject took ownership +template <class T> +inline bool WrapNewBindingNonWrapperCachedObject( + JSContext* cx, JS::Handle<JSObject*> scopeArg, UniquePtr<T>& value, + JS::MutableHandle<JS::Value> rval, + JS::Handle<JSObject*> givenProto = nullptr) { + static_assert(!IsRefcounted<T>::value, "Only pass owned classes in here."); + // We do a runtime check on value, because otherwise we might in + // fact end up wrapping a null and invoking methods on it later. + if (!value) { + MOZ_CRASH("Don't try to wrap null objects"); + } + // We try to wrap in the realm of the underlying object of "scope" + JS::Rooted<JSObject*> obj(cx); + { + // scope for the JSAutoRealm so that we restore the realm + // before we call JS_WrapValue. + Maybe<JSAutoRealm> ar; + // Maybe<Handle> doesn't so much work, and in any case, adding + // more Maybe (one for a Rooted and one for a Handle) adds more + // code (and branches!) than just adding a single rooted. + JS::Rooted<JSObject*> scope(cx, scopeArg); + JS::Rooted<JSObject*> proto(cx, givenProto); + if (js::IsWrapper(scope)) { + // We are working in the Realm of cx and will be producing our reflector + // there, so we need to succeed if that realm has access to the scope. + scope = + js::CheckedUnwrapDynamic(scope, cx, /* stopAtWindowProxy = */ false); + if (!scope) return false; + ar.emplace(cx, scope); + if (!JS_WrapObject(cx, &proto)) { + return false; + } + } else { + // cx and scope are same-compartment, but they might still be + // different-Realm. Enter the Realm of scope, since that's + // where we want to create our object. + ar.emplace(cx, scope); + } + + MOZ_ASSERT_IF(proto, js::IsObjectInContextCompartment(proto, cx)); + MOZ_ASSERT(js::IsObjectInContextCompartment(scope, cx)); + if (!value->WrapObject(cx, proto, &obj)) { + return false; + } + + // JS object took ownership + Unused << value.release(); + } + + return FinishWrapping(cx, obj, rval); +} + +// Helper for smart pointers (nsRefPtr/nsCOMPtr). +template <template <typename> class SmartPtr, typename T, + typename U = std::enable_if_t<IsRefcounted<T>::value, T>, + typename V = std::enable_if_t<IsSmartPtr<SmartPtr<T>>::value, T>> +inline bool WrapNewBindingNonWrapperCachedObject( + JSContext* cx, JS::Handle<JSObject*> scope, const SmartPtr<T>& value, + JS::MutableHandle<JS::Value> rval, + JS::Handle<JSObject*> givenProto = nullptr) { + return WrapNewBindingNonWrapperCachedObject(cx, scope, value.get(), rval, + givenProto); +} + +// Helper for object references (as opposed to pointers). +template <typename T, typename U = std::enable_if_t<!IsSmartPtr<T>::value, T>> +inline bool WrapNewBindingNonWrapperCachedObject( + JSContext* cx, JS::Handle<JSObject*> scope, T& value, + JS::MutableHandle<JS::Value> rval, + JS::Handle<JSObject*> givenProto = nullptr) { + return WrapNewBindingNonWrapperCachedObject(cx, scope, &value, rval, + givenProto); +} + +template <bool Fatal> +inline bool EnumValueNotFound(BindingCallContext& cx, JS::Handle<JSString*> str, + const char* type, const char* sourceDescription); + +template <> +inline bool EnumValueNotFound<false>(BindingCallContext& cx, + JS::Handle<JSString*> str, + const char* type, + const char* sourceDescription) { + // TODO: Log a warning to the console. + return true; +} + +template <> +inline bool EnumValueNotFound<true>(BindingCallContext& cx, + JS::Handle<JSString*> str, const char* type, + const char* sourceDescription) { + JS::UniqueChars deflated = JS_EncodeStringToUTF8(cx, str); + if (!deflated) { + return false; + } + return cx.ThrowErrorMessage<MSG_INVALID_ENUM_VALUE>(sourceDescription, + deflated.get(), type); +} + +template <typename CharT> +inline int FindEnumStringIndexImpl(const CharT* chars, size_t length, + const EnumEntry* values) { + int i = 0; + for (const EnumEntry* value = values; value->value; ++value, ++i) { + if (length != value->length) { + continue; + } + + bool equal = true; + const char* val = value->value; + for (size_t j = 0; j != length; ++j) { + if (unsigned(val[j]) != unsigned(chars[j])) { + equal = false; + break; + } + } + + if (equal) { + return i; + } + } + + return -1; +} + +template <bool InvalidValueFatal> +inline bool FindEnumStringIndex(BindingCallContext& cx, JS::Handle<JS::Value> v, + const EnumEntry* values, const char* type, + const char* sourceDescription, int* index) { + // JS_StringEqualsAscii is slow as molasses, so don't use it here. + JS::Rooted<JSString*> str(cx, JS::ToString(cx, v)); + if (!str) { + return false; + } + + { + size_t length; + JS::AutoCheckCannotGC nogc; + if (JS::StringHasLatin1Chars(str)) { + const JS::Latin1Char* chars = + JS_GetLatin1StringCharsAndLength(cx, nogc, str, &length); + if (!chars) { + return false; + } + *index = FindEnumStringIndexImpl(chars, length, values); + } else { + const char16_t* chars = + JS_GetTwoByteStringCharsAndLength(cx, nogc, str, &length); + if (!chars) { + return false; + } + *index = FindEnumStringIndexImpl(chars, length, values); + } + if (*index >= 0) { + return true; + } + } + + return EnumValueNotFound<InvalidValueFatal>(cx, str, type, sourceDescription); +} + +inline nsWrapperCache* GetWrapperCache(const ParentObject& aParentObject) { + return aParentObject.mWrapperCache; +} + +template <class T> +inline T* GetParentPointer(T* aObject) { + return aObject; +} + +inline nsISupports* GetParentPointer(const ParentObject& aObject) { + return aObject.mObject; +} + +template <typename T> +inline mozilla::dom::ReflectionScope GetReflectionScope(T* aParentObject) { + return mozilla::dom::ReflectionScope::Content; +} + +inline mozilla::dom::ReflectionScope GetReflectionScope( + const ParentObject& aParentObject) { + return aParentObject.mReflectionScope; +} + +template <class T> +inline void ClearWrapper(T* p, nsWrapperCache* cache, JSObject* obj) { + MOZ_ASSERT(cache->GetWrapperMaybeDead() == obj || + (js::RuntimeIsBeingDestroyed() && !cache->GetWrapperMaybeDead())); + cache->ClearWrapper(obj); +} + +template <class T> +inline void ClearWrapper(T* p, void*, JSObject* obj) { + // QueryInterface to nsWrapperCache can't GC, we hope. + JS::AutoSuppressGCAnalysis nogc; + + nsWrapperCache* cache; + CallQueryInterface(p, &cache); + ClearWrapper(p, cache, obj); +} + +template <class T> +inline void UpdateWrapper(T* p, nsWrapperCache* cache, JSObject* obj, + const JSObject* old) { + JS::AutoAssertGCCallback inCallback; + cache->UpdateWrapper(obj, old); +} + +template <class T> +inline void UpdateWrapper(T* p, void*, JSObject* obj, const JSObject* old) { + JS::AutoAssertGCCallback inCallback; + nsWrapperCache* cache; + CallQueryInterface(p, &cache); + UpdateWrapper(p, cache, obj, old); +} + +// Attempt to preserve the wrapper, if any, for a Paris DOM bindings object. +// Return true if we successfully preserved the wrapper, or there is no wrapper +// to preserve. In the latter case we don't need to preserve the wrapper, +// because the object can only be obtained by JS once, or they cannot be +// meaningfully owned from the native side. +// +// This operation will return false only for non-nsISupports cycle-collected +// objects, because we cannot determine if they are wrappercached or not. +bool TryPreserveWrapper(JS::Handle<JSObject*> obj); + +bool HasReleasedWrapper(JS::Handle<JSObject*> obj); + +// Can only be called with a DOM JSClass. +bool InstanceClassHasProtoAtDepth(const JSClass* clasp, uint32_t protoID, + uint32_t depth); + +// Only set allowNativeWrapper to false if you really know you need it; if in +// doubt use true. Setting it to false disables security wrappers. +bool XPCOMObjectToJsval(JSContext* cx, JS::Handle<JSObject*> scope, + xpcObjectHelper& helper, const nsIID* iid, + bool allowNativeWrapper, + JS::MutableHandle<JS::Value> rval); + +// Special-cased wrapping for variants +bool VariantToJsval(JSContext* aCx, nsIVariant* aVariant, + JS::MutableHandle<JS::Value> aRetval); + +// Wrap an object "p" which is not using WebIDL bindings yet. This _will_ +// actually work on WebIDL binding objects that are wrappercached, but will be +// much slower than GetOrCreateDOMReflector. "cache" must either be null or be +// the nsWrapperCache for "p". +template <class T> +inline bool WrapObject(JSContext* cx, T* p, nsWrapperCache* cache, + const nsIID* iid, JS::MutableHandle<JS::Value> rval) { + if (xpc_FastGetCachedWrapper(cx, cache, rval)) return true; + xpcObjectHelper helper(ToSupports(p), cache); + JS::Rooted<JSObject*> scope(cx, JS::CurrentGlobalOrNull(cx)); + return XPCOMObjectToJsval(cx, scope, helper, iid, true, rval); +} + +// A specialization of the above for nsIVariant, because that needs to +// do something different. +template <> +inline bool WrapObject<nsIVariant>(JSContext* cx, nsIVariant* p, + nsWrapperCache* cache, const nsIID* iid, + JS::MutableHandle<JS::Value> rval) { + MOZ_ASSERT(iid); + MOZ_ASSERT(iid->Equals(NS_GET_IID(nsIVariant))); + return VariantToJsval(cx, p, rval); +} + +// Wrap an object "p" which is not using WebIDL bindings yet. Just like the +// variant that takes an nsWrapperCache above, but will try to auto-derive the +// nsWrapperCache* from "p". +template <class T> +inline bool WrapObject(JSContext* cx, T* p, const nsIID* iid, + JS::MutableHandle<JS::Value> rval) { + return WrapObject(cx, p, GetWrapperCache(p), iid, rval); +} + +// Just like the WrapObject above, but without requiring you to pick which +// interface you're wrapping as. This should only be used for objects that have +// classinfo, for which it doesn't matter what IID is used to wrap. +template <class T> +inline bool WrapObject(JSContext* cx, T* p, JS::MutableHandle<JS::Value> rval) { + return WrapObject(cx, p, nullptr, rval); +} + +// Helper to make it possible to wrap directly out of an nsCOMPtr +template <class T> +inline bool WrapObject(JSContext* cx, const nsCOMPtr<T>& p, const nsIID* iid, + JS::MutableHandle<JS::Value> rval) { + return WrapObject(cx, p.get(), iid, rval); +} + +// Helper to make it possible to wrap directly out of an nsCOMPtr +template <class T> +inline bool WrapObject(JSContext* cx, const nsCOMPtr<T>& p, + JS::MutableHandle<JS::Value> rval) { + return WrapObject(cx, p, nullptr, rval); +} + +// Helper to make it possible to wrap directly out of an nsRefPtr +template <class T> +inline bool WrapObject(JSContext* cx, const RefPtr<T>& p, const nsIID* iid, + JS::MutableHandle<JS::Value> rval) { + return WrapObject(cx, p.get(), iid, rval); +} + +// Helper to make it possible to wrap directly out of an nsRefPtr +template <class T> +inline bool WrapObject(JSContext* cx, const RefPtr<T>& p, + JS::MutableHandle<JS::Value> rval) { + return WrapObject(cx, p, nullptr, rval); +} + +// Specialization to make it easy to use WrapObject in codegen. +template <> +inline bool WrapObject<JSObject>(JSContext* cx, JSObject* p, + JS::MutableHandle<JS::Value> rval) { + rval.set(JS::ObjectOrNullValue(p)); + return true; +} + +inline bool WrapObject(JSContext* cx, JSObject& p, + JS::MutableHandle<JS::Value> rval) { + rval.set(JS::ObjectValue(p)); + return true; +} + +bool WrapObject(JSContext* cx, const WindowProxyHolder& p, + JS::MutableHandle<JS::Value> rval); + +// Given an object "p" that inherits from nsISupports, wrap it and return the +// result. Null is returned on wrapping failure. This is somewhat similar to +// WrapObject() above, but does NOT allow Xrays around the result, since we +// don't want those for our parent object. +template <typename T> +static inline JSObject* WrapNativeISupports(JSContext* cx, T* p, + nsWrapperCache* cache) { + JS::Rooted<JSObject*> retval(cx); + { + xpcObjectHelper helper(ToSupports(p), cache); + JS::Rooted<JSObject*> scope(cx, JS::CurrentGlobalOrNull(cx)); + JS::Rooted<JS::Value> v(cx); + retval = XPCOMObjectToJsval(cx, scope, helper, nullptr, false, &v) + ? v.toObjectOrNull() + : nullptr; + } + return retval; +} + +// Wrapping of our native parent, for cases when it's a WebIDL object. +template <typename T, bool hasWrapObject = NativeHasMember<T>::WrapObject> +struct WrapNativeHelper { + static inline JSObject* Wrap(JSContext* cx, T* parent, + nsWrapperCache* cache) { + MOZ_ASSERT(cache); + + JSObject* obj; + if ((obj = cache->GetWrapper())) { + // GetWrapper always unmarks gray. + JS::AssertObjectIsNotGray(obj); + return obj; + } + + // WrapObject never returns a gray thing. + obj = parent->WrapObject(cx, nullptr); + JS::AssertObjectIsNotGray(obj); + + return obj; + } +}; + +// Wrapping of our native parent, for cases when it's not a WebIDL object. In +// this case it must be nsISupports. +template <typename T> +struct WrapNativeHelper<T, false> { + static inline JSObject* Wrap(JSContext* cx, T* parent, + nsWrapperCache* cache) { + JSObject* obj; + if (cache && (obj = cache->GetWrapper())) { +#ifdef DEBUG + JS::Rooted<JSObject*> rootedObj(cx, obj); + NS_ASSERTION(WrapNativeISupports(cx, parent, cache) == rootedObj, + "Unexpected object in nsWrapperCache"); + obj = rootedObj; +#endif + JS::AssertObjectIsNotGray(obj); + return obj; + } + + obj = WrapNativeISupports(cx, parent, cache); + JS::AssertObjectIsNotGray(obj); + return obj; + } +}; + +// Finding the associated global for an object. +template <typename T> +static inline JSObject* FindAssociatedGlobal( + JSContext* cx, T* p, nsWrapperCache* cache, + mozilla::dom::ReflectionScope scope = + mozilla::dom::ReflectionScope::Content) { + if (!p) { + return JS::CurrentGlobalOrNull(cx); + } + + JSObject* obj = WrapNativeHelper<T>::Wrap(cx, p, cache); + if (!obj) { + return nullptr; + } + JS::AssertObjectIsNotGray(obj); + + // The object is never a CCW but it may not be in the current compartment of + // the JSContext. + obj = JS::GetNonCCWObjectGlobal(obj); + + switch (scope) { + case mozilla::dom::ReflectionScope::NAC: { + return xpc::NACScope(obj); + } + + case mozilla::dom::ReflectionScope::UAWidget: { + // If scope is set to UAWidgetScope, it means that the canonical reflector + // for this native object should live in the UA widget scope. + if (xpc::IsInUAWidgetScope(obj)) { + return obj; + } + JS::Rooted<JSObject*> rootedObj(cx, obj); + JSObject* uaWidgetScope = xpc::GetUAWidgetScope(cx, rootedObj); + MOZ_ASSERT_IF(uaWidgetScope, JS_IsGlobalObject(uaWidgetScope)); + JS::AssertObjectIsNotGray(uaWidgetScope); + return uaWidgetScope; + } + + case ReflectionScope::Content: + return obj; + } + + MOZ_CRASH("Unknown ReflectionScope variant"); + + return nullptr; +} + +// Finding of the associated global for an object, when we don't want to +// explicitly pass in things like the nsWrapperCache for it. +template <typename T> +static inline JSObject* FindAssociatedGlobal(JSContext* cx, const T& p) { + return FindAssociatedGlobal(cx, GetParentPointer(p), GetWrapperCache(p), + GetReflectionScope(p)); +} + +// Specialization for the case of nsIGlobalObject, since in that case +// we can just get the JSObject* directly. +template <> +inline JSObject* FindAssociatedGlobal(JSContext* cx, + nsIGlobalObject* const& p) { + if (!p) { + return JS::CurrentGlobalOrNull(cx); + } + + JSObject* global = p->GetGlobalJSObject(); + if (!global) { + // nsIGlobalObject doesn't have a JS object anymore, + // fallback to the current global. + return JS::CurrentGlobalOrNull(cx); + } + + MOZ_ASSERT(JS_IsGlobalObject(global)); + JS::AssertObjectIsNotGray(global); + return global; +} + +template <typename T, + bool hasAssociatedGlobal = NativeHasMember<T>::GetParentObject> +struct FindAssociatedGlobalForNative { + static JSObject* Get(JSContext* cx, JS::Handle<JSObject*> obj) { + MOZ_ASSERT(js::IsObjectInContextCompartment(obj, cx)); + T* native = UnwrapDOMObject<T>(obj); + return FindAssociatedGlobal(cx, native->GetParentObject()); + } +}; + +template <typename T> +struct FindAssociatedGlobalForNative<T, false> { + static JSObject* Get(JSContext* cx, JS::Handle<JSObject*> obj) { + MOZ_CRASH(); + return nullptr; + } +}; + +// Helper for calling GetOrCreateDOMReflector with smart pointers +// (UniquePtr/RefPtr/nsCOMPtr) or references. +template <class T, bool isSmartPtr = IsSmartPtr<T>::value> +struct GetOrCreateDOMReflectorHelper { + static inline bool GetOrCreate(JSContext* cx, const T& value, + JS::Handle<JSObject*> givenProto, + JS::MutableHandle<JS::Value> rval) { + return GetOrCreateDOMReflector(cx, value.get(), rval, givenProto); + } +}; + +template <class T> +struct GetOrCreateDOMReflectorHelper<T, false> { + static inline bool GetOrCreate(JSContext* cx, T& value, + JS::Handle<JSObject*> givenProto, + JS::MutableHandle<JS::Value> rval) { + static_assert(IsRefcounted<T>::value, "Don't pass owned classes in here."); + return GetOrCreateDOMReflector(cx, &value, rval, givenProto); + } +}; + +template <class T> +inline bool GetOrCreateDOMReflector( + JSContext* cx, T& value, JS::MutableHandle<JS::Value> rval, + JS::Handle<JSObject*> givenProto = nullptr) { + return GetOrCreateDOMReflectorHelper<T>::GetOrCreate(cx, value, givenProto, + rval); +} + +// Helper for calling GetOrCreateDOMReflectorNoWrap with smart pointers +// (UniquePtr/RefPtr/nsCOMPtr) or references. +template <class T, bool isSmartPtr = IsSmartPtr<T>::value> +struct GetOrCreateDOMReflectorNoWrapHelper { + static inline bool GetOrCreate(JSContext* cx, const T& value, + JS::MutableHandle<JS::Value> rval) { + return GetOrCreateDOMReflectorNoWrap(cx, value.get(), rval); + } +}; + +template <class T> +struct GetOrCreateDOMReflectorNoWrapHelper<T, false> { + static inline bool GetOrCreate(JSContext* cx, T& value, + JS::MutableHandle<JS::Value> rval) { + return GetOrCreateDOMReflectorNoWrap(cx, &value, rval); + } +}; + +template <class T> +inline bool GetOrCreateDOMReflectorNoWrap(JSContext* cx, T& value, + JS::MutableHandle<JS::Value> rval) { + return GetOrCreateDOMReflectorNoWrapHelper<T>::GetOrCreate(cx, value, rval); +} + +template <class T> +inline JSObject* GetCallbackFromCallbackObject(JSContext* aCx, T* aObj) { + return aObj->Callback(aCx); +} + +// Helper for getting the callback JSObject* of a smart ptr around a +// CallbackObject or a reference to a CallbackObject or something like +// that. +template <class T, bool isSmartPtr = IsSmartPtr<T>::value> +struct GetCallbackFromCallbackObjectHelper { + static inline JSObject* Get(JSContext* aCx, const T& aObj) { + return GetCallbackFromCallbackObject(aCx, aObj.get()); + } +}; + +template <class T> +struct GetCallbackFromCallbackObjectHelper<T, false> { + static inline JSObject* Get(JSContext* aCx, T& aObj) { + return GetCallbackFromCallbackObject(aCx, &aObj); + } +}; + +template <class T> +inline JSObject* GetCallbackFromCallbackObject(JSContext* aCx, T& aObj) { + return GetCallbackFromCallbackObjectHelper<T>::Get(aCx, aObj); +} + +static inline bool AtomizeAndPinJSString(JSContext* cx, jsid& id, + const char* chars) { + if (JSString* str = ::JS_AtomizeAndPinString(cx, chars)) { + id = JS::PropertyKey::fromPinnedString(str); + return true; + } + return false; +} + +void GetInterfaceImpl(JSContext* aCx, nsIInterfaceRequestor* aRequestor, + nsWrapperCache* aCache, JS::Handle<JS::Value> aIID, + JS::MutableHandle<JS::Value> aRetval, + ErrorResult& aError); + +template <class T> +void GetInterface(JSContext* aCx, T* aThis, JS::Handle<JS::Value> aIID, + JS::MutableHandle<JS::Value> aRetval, ErrorResult& aError) { + GetInterfaceImpl(aCx, aThis, aThis, aIID, aRetval, aError); +} + +bool ThrowingConstructor(JSContext* cx, unsigned argc, JS::Value* vp); + +bool ThrowConstructorWithoutNew(JSContext* cx, const char* name); + +// Helper for throwing an "invalid this" exception. +bool ThrowInvalidThis(JSContext* aCx, const JS::CallArgs& aArgs, + bool aSecurityError, prototypes::ID aProtoId); + +bool GetPropertyOnPrototype(JSContext* cx, JS::Handle<JSObject*> proxy, + JS::Handle<JS::Value> receiver, JS::Handle<jsid> id, + bool* found, JS::MutableHandle<JS::Value> vp); + +// +bool HasPropertyOnPrototype(JSContext* cx, JS::Handle<JSObject*> proxy, + JS::Handle<jsid> id, bool* has); + +// Append the property names in "names" to "props". If +// shadowPrototypeProperties is false then skip properties that are also +// present on the proto chain of proxy. If shadowPrototypeProperties is true, +// then the "proxy" argument is ignored. +bool AppendNamedPropertyIds(JSContext* cx, JS::Handle<JSObject*> proxy, + nsTArray<nsString>& names, + bool shadowPrototypeProperties, + JS::MutableHandleVector<jsid> props); + +enum StringificationBehavior { eStringify, eEmpty, eNull }; + +static inline JSString* ConvertJSValueToJSString(JSContext* cx, + JS::Handle<JS::Value> v) { + if (MOZ_LIKELY(v.isString())) { + return v.toString(); + } + return JS::ToString(cx, v); +} + +template <typename T> +static inline bool ConvertJSValueToString( + JSContext* cx, JS::Handle<JS::Value> v, + StringificationBehavior nullBehavior, + StringificationBehavior undefinedBehavior, T& result) { + JSString* s; + if (v.isString()) { + s = v.toString(); + } else { + StringificationBehavior behavior; + if (v.isNull()) { + behavior = nullBehavior; + } else if (v.isUndefined()) { + behavior = undefinedBehavior; + } else { + behavior = eStringify; + } + + if (behavior != eStringify) { + if (behavior == eEmpty) { + result.Truncate(); + } else { + result.SetIsVoid(true); + } + return true; + } + + s = JS::ToString(cx, v); + if (!s) { + return false; + } + } + + return AssignJSString(cx, result, s); +} + +template <typename T> +static inline bool ConvertJSValueToString( + JSContext* cx, JS::Handle<JS::Value> v, + const char* /* unused sourceDescription */, T& result) { + return ConvertJSValueToString(cx, v, eStringify, eStringify, result); +} + +[[nodiscard]] bool NormalizeUSVString(nsAString& aString); + +[[nodiscard]] bool NormalizeUSVString( + binding_detail::FakeString<char16_t>& aString); + +template <typename T> +static inline bool ConvertJSValueToUSVString( + JSContext* cx, JS::Handle<JS::Value> v, + const char* /* unused sourceDescription */, T& result) { + if (!ConvertJSValueToString(cx, v, eStringify, eStringify, result)) { + return false; + } + + if (!NormalizeUSVString(result)) { + JS_ReportOutOfMemory(cx); + return false; + } + + return true; +} + +template <typename T> +inline bool ConvertIdToString(JSContext* cx, JS::Handle<JS::PropertyKey> id, + T& result, bool& isSymbol) { + if (MOZ_LIKELY(id.isString())) { + if (!AssignJSString(cx, result, id.toString())) { + return false; + } + } else if (id.isSymbol()) { + isSymbol = true; + return true; + } else { + JS::Rooted<JS::Value> nameVal(cx, js::IdToValue(id)); + if (!ConvertJSValueToString(cx, nameVal, eStringify, eStringify, result)) { + return false; + } + } + isSymbol = false; + return true; +} + +bool ConvertJSValueToByteString(BindingCallContext& cx, JS::Handle<JS::Value> v, + bool nullable, const char* sourceDescription, + nsACString& result); + +inline bool ConvertJSValueToByteString(BindingCallContext& cx, + JS::Handle<JS::Value> v, + const char* sourceDescription, + nsACString& result) { + return ConvertJSValueToByteString(cx, v, false, sourceDescription, result); +} + +template <typename T> +void DoTraceSequence(JSTracer* trc, FallibleTArray<T>& seq); +template <typename T> +void DoTraceSequence(JSTracer* trc, nsTArray<T>& seq); + +// Class used to trace sequences, with specializations for various +// sequence types. +template <typename T, + bool isDictionary = std::is_base_of<DictionaryBase, T>::value, + bool isTypedArray = std::is_base_of<AllTypedArraysBase, T>::value, + bool isOwningUnion = std::is_base_of<AllOwningUnionBase, T>::value> +class SequenceTracer { + explicit SequenceTracer() = delete; // Should never be instantiated +}; + +// sequence<object> or sequence<object?> +template <> +class SequenceTracer<JSObject*, false, false, false> { + explicit SequenceTracer() = delete; // Should never be instantiated + + public: + static void TraceSequence(JSTracer* trc, JSObject** objp, JSObject** end) { + for (; objp != end; ++objp) { + JS::TraceRoot(trc, objp, "sequence<object>"); + } + } +}; + +// sequence<any> +template <> +class SequenceTracer<JS::Value, false, false, false> { + explicit SequenceTracer() = delete; // Should never be instantiated + + public: + static void TraceSequence(JSTracer* trc, JS::Value* valp, JS::Value* end) { + for (; valp != end; ++valp) { + JS::TraceRoot(trc, valp, "sequence<any>"); + } + } +}; + +// sequence<sequence<T>> +template <typename T> +class SequenceTracer<Sequence<T>, false, false, false> { + explicit SequenceTracer() = delete; // Should never be instantiated + + public: + static void TraceSequence(JSTracer* trc, Sequence<T>* seqp, + Sequence<T>* end) { + for (; seqp != end; ++seqp) { + DoTraceSequence(trc, *seqp); + } + } +}; + +// sequence<sequence<T>> as return value +template <typename T> +class SequenceTracer<nsTArray<T>, false, false, false> { + explicit SequenceTracer() = delete; // Should never be instantiated + + public: + static void TraceSequence(JSTracer* trc, nsTArray<T>* seqp, + nsTArray<T>* end) { + for (; seqp != end; ++seqp) { + DoTraceSequence(trc, *seqp); + } + } +}; + +// sequence<someDictionary> +template <typename T> +class SequenceTracer<T, true, false, false> { + explicit SequenceTracer() = delete; // Should never be instantiated + + public: + static void TraceSequence(JSTracer* trc, T* dictp, T* end) { + for (; dictp != end; ++dictp) { + dictp->TraceDictionary(trc); + } + } +}; + +// sequence<SomeTypedArray> +template <typename T> +class SequenceTracer<T, false, true, false> { + explicit SequenceTracer() = delete; // Should never be instantiated + + public: + static void TraceSequence(JSTracer* trc, T* arrayp, T* end) { + for (; arrayp != end; ++arrayp) { + arrayp->TraceSelf(trc); + } + } +}; + +// sequence<SomeOwningUnion> +template <typename T> +class SequenceTracer<T, false, false, true> { + explicit SequenceTracer() = delete; // Should never be instantiated + + public: + static void TraceSequence(JSTracer* trc, T* arrayp, T* end) { + for (; arrayp != end; ++arrayp) { + arrayp->TraceUnion(trc); + } + } +}; + +// sequence<T?> with T? being a Nullable<T> +template <typename T> +class SequenceTracer<Nullable<T>, false, false, false> { + explicit SequenceTracer() = delete; // Should never be instantiated + + public: + static void TraceSequence(JSTracer* trc, Nullable<T>* seqp, + Nullable<T>* end) { + for (; seqp != end; ++seqp) { + if (!seqp->IsNull()) { + // Pretend like we actually have a length-one sequence here so + // we can do template instantiation correctly for T. + T& val = seqp->Value(); + T* ptr = &val; + SequenceTracer<T>::TraceSequence(trc, ptr, ptr + 1); + } + } + } +}; + +template <typename K, typename V> +void TraceRecord(JSTracer* trc, Record<K, V>& record) { + for (auto& entry : record.Entries()) { + // Act like it's a one-element sequence to leverage all that infrastructure. + SequenceTracer<V>::TraceSequence(trc, &entry.mValue, &entry.mValue + 1); + } +} + +// sequence<record> +template <typename K, typename V> +class SequenceTracer<Record<K, V>, false, false, false> { + explicit SequenceTracer() = delete; // Should never be instantiated + + public: + static void TraceSequence(JSTracer* trc, Record<K, V>* seqp, + Record<K, V>* end) { + for (; seqp != end; ++seqp) { + TraceRecord(trc, *seqp); + } + } +}; + +template <typename T> +void DoTraceSequence(JSTracer* trc, FallibleTArray<T>& seq) { + SequenceTracer<T>::TraceSequence(trc, seq.Elements(), + seq.Elements() + seq.Length()); +} + +template <typename T> +void DoTraceSequence(JSTracer* trc, nsTArray<T>& seq) { + SequenceTracer<T>::TraceSequence(trc, seq.Elements(), + seq.Elements() + seq.Length()); +} + +// Rooter class for sequences; this is what we mostly use in the codegen +template <typename T> +class MOZ_RAII SequenceRooter final : private JS::CustomAutoRooter { + public: + template <typename CX> + SequenceRooter(const CX& cx, FallibleTArray<T>* aSequence) + : JS::CustomAutoRooter(cx), + mFallibleArray(aSequence), + mSequenceType(eFallibleArray) {} + + template <typename CX> + SequenceRooter(const CX& cx, nsTArray<T>* aSequence) + : JS::CustomAutoRooter(cx), + mInfallibleArray(aSequence), + mSequenceType(eInfallibleArray) {} + + template <typename CX> + SequenceRooter(const CX& cx, Nullable<nsTArray<T>>* aSequence) + : JS::CustomAutoRooter(cx), + mNullableArray(aSequence), + mSequenceType(eNullableArray) {} + + private: + enum SequenceType { eInfallibleArray, eFallibleArray, eNullableArray }; + + virtual void trace(JSTracer* trc) override { + if (mSequenceType == eFallibleArray) { + DoTraceSequence(trc, *mFallibleArray); + } else if (mSequenceType == eInfallibleArray) { + DoTraceSequence(trc, *mInfallibleArray); + } else { + MOZ_ASSERT(mSequenceType == eNullableArray); + if (!mNullableArray->IsNull()) { + DoTraceSequence(trc, mNullableArray->Value()); + } + } + } + + union { + nsTArray<T>* mInfallibleArray; + FallibleTArray<T>* mFallibleArray; + Nullable<nsTArray<T>>* mNullableArray; + }; + + SequenceType mSequenceType; +}; + +// Rooter class for Record; this is what we mostly use in the codegen. +template <typename K, typename V> +class MOZ_RAII RecordRooter final : private JS::CustomAutoRooter { + public: + template <typename CX> + RecordRooter(const CX& cx, Record<K, V>* aRecord) + : JS::CustomAutoRooter(cx), mRecord(aRecord), mRecordType(eRecord) {} + + template <typename CX> + RecordRooter(const CX& cx, Nullable<Record<K, V>>* aRecord) + : JS::CustomAutoRooter(cx), + mNullableRecord(aRecord), + mRecordType(eNullableRecord) {} + + private: + enum RecordType { eRecord, eNullableRecord }; + + virtual void trace(JSTracer* trc) override { + if (mRecordType == eRecord) { + TraceRecord(trc, *mRecord); + } else { + MOZ_ASSERT(mRecordType == eNullableRecord); + if (!mNullableRecord->IsNull()) { + TraceRecord(trc, mNullableRecord->Value()); + } + } + } + + union { + Record<K, V>* mRecord; + Nullable<Record<K, V>>* mNullableRecord; + }; + + RecordType mRecordType; +}; + +template <typename T> +class MOZ_RAII RootedUnion : public T, private JS::CustomAutoRooter { + public: + template <typename CX> + explicit RootedUnion(const CX& cx) : T(), JS::CustomAutoRooter(cx) {} + + virtual void trace(JSTracer* trc) override { this->TraceUnion(trc); } +}; + +template <typename T> +class MOZ_STACK_CLASS NullableRootedUnion : public Nullable<T>, + private JS::CustomAutoRooter { + public: + template <typename CX> + explicit NullableRootedUnion(const CX& cx) + : Nullable<T>(), JS::CustomAutoRooter(cx) {} + + virtual void trace(JSTracer* trc) override { + if (!this->IsNull()) { + this->Value().TraceUnion(trc); + } + } +}; + +inline bool AddStringToIDVector(JSContext* cx, + JS::MutableHandleVector<jsid> vector, + const char* name) { + return vector.growBy(1) && + AtomizeAndPinJSString(cx, *(vector[vector.length() - 1]).address(), + name); +} + +// We use one constructor JSNative to represent all DOM interface objects (so +// we can easily detect when we need to wrap them in an Xray wrapper). We store +// the real JSNative in the mNative member of a JSNativeHolder in the +// CONSTRUCTOR_NATIVE_HOLDER_RESERVED_SLOT slot of the JSFunction object for a +// specific interface object. We also store the NativeProperties in the +// JSNativeHolder. +// Note that some interface objects are not yet a JSFunction but a normal +// JSObject with a DOMJSClass, those do not use these slots. + +enum { CONSTRUCTOR_NATIVE_HOLDER_RESERVED_SLOT = 0 }; + +bool Constructor(JSContext* cx, unsigned argc, JS::Value* vp); + +// Implementation of the bits that XrayWrapper needs + +/** + * This resolves operations, attributes and constants of the interfaces for obj. + * + * wrapper is the Xray JS object. + * obj is the target object of the Xray, a binding's instance object or a + * interface or interface prototype object. + */ +bool XrayResolveOwnProperty( + JSContext* cx, JS::Handle<JSObject*> wrapper, JS::Handle<JSObject*> obj, + JS::Handle<jsid> id, + JS::MutableHandle<mozilla::Maybe<JS::PropertyDescriptor>> desc, + bool& cacheOnHolder); + +/** + * Define a property on obj through an Xray wrapper. + * + * wrapper is the Xray JS object. + * obj is the target object of the Xray, a binding's instance object or a + * interface or interface prototype object. + * id and desc are the parameters for the property to be defined. + * result is the out-parameter indicating success (read it only if + * this returns true and also sets *done to true). + * done will be set to true if a property was set as a result of this call + * or if we want to always avoid setting this property + * (i.e. indexed properties on DOM objects) + */ +bool XrayDefineProperty(JSContext* cx, JS::Handle<JSObject*> wrapper, + JS::Handle<JSObject*> obj, JS::Handle<jsid> id, + JS::Handle<JS::PropertyDescriptor> desc, + JS::ObjectOpResult& result, bool* done); + +/** + * Add to props the property keys of all indexed or named properties of obj and + * operations, attributes and constants of the interfaces for obj. + * + * wrapper is the Xray JS object. + * obj is the target object of the Xray, a binding's instance object or a + * interface or interface prototype object. + * flags are JSITER_* flags. + */ +bool XrayOwnPropertyKeys(JSContext* cx, JS::Handle<JSObject*> wrapper, + JS::Handle<JSObject*> obj, unsigned flags, + JS::MutableHandleVector<jsid> props); + +/** + * Returns the prototype to use for an Xray for a DOM object, wrapped in cx's + * compartment. This always returns the prototype that would be used for a DOM + * object if we ignore any changes that might have been done to the prototype + * chain by JS, the XBL code or plugins. + * + * cx should be in the Xray's compartment. + * obj is the target object of the Xray, a binding's instance object or an + * interface or interface prototype object. + */ +inline bool XrayGetNativeProto(JSContext* cx, JS::Handle<JSObject*> obj, + JS::MutableHandle<JSObject*> protop) { + JS::Rooted<JSObject*> global(cx, JS::GetNonCCWObjectGlobal(obj)); + { + JSAutoRealm ar(cx, global); + const DOMJSClass* domClass = GetDOMClass(obj); + if (domClass) { + ProtoHandleGetter protoGetter = domClass->mGetProto; + if (protoGetter) { + protop.set(protoGetter(cx)); + } else { + protop.set(JS::GetRealmObjectPrototype(cx)); + } + } else if (JS_ObjectIsFunction(obj)) { + MOZ_ASSERT(JS_IsNativeFunction(obj, Constructor)); + protop.set(JS::GetRealmFunctionPrototype(cx)); + } else { + const JSClass* clasp = JS::GetClass(obj); + MOZ_ASSERT(IsDOMIfaceAndProtoClass(clasp)); + ProtoGetter protoGetter = + DOMIfaceAndProtoJSClass::FromJSClass(clasp)->mGetParentProto; + protop.set(protoGetter(cx)); + } + } + + return JS_WrapObject(cx, protop); +} + +/** + * Get the Xray expando class to use for the given DOM object. + */ +const JSClass* XrayGetExpandoClass(JSContext* cx, JS::Handle<JSObject*> obj); + +/** + * Delete a named property, if any. Return value is false if exception thrown, + * true otherwise. The caller should not do any more work after calling this + * function, because it has no way whether a deletion was performed and hence + * opresult already has state set on it. If callers ever need to change that, + * add a "bool* found" argument and change the generated DeleteNamedProperty to + * use it instead of a local variable. + */ +bool XrayDeleteNamedProperty(JSContext* cx, JS::Handle<JSObject*> wrapper, + JS::Handle<JSObject*> obj, JS::Handle<jsid> id, + JS::ObjectOpResult& opresult); + +namespace binding_detail { + +// Default implementations of the NativePropertyHooks' mResolveOwnProperty and +// mEnumerateOwnProperties for WebIDL bindings implemented as proxies. +bool ResolveOwnProperty( + JSContext* cx, JS::Handle<JSObject*> wrapper, JS::Handle<JSObject*> obj, + JS::Handle<jsid> id, + JS::MutableHandle<mozilla::Maybe<JS::PropertyDescriptor>> desc); +bool EnumerateOwnProperties(JSContext* cx, JS::Handle<JSObject*> wrapper, + JS::Handle<JSObject*> obj, + JS::MutableHandleVector<jsid> props); + +} // namespace binding_detail + +/** + * Get the object which should be used to cache the return value of a property + * getter in the case of a [Cached] or [StoreInSlot] property. `obj` is the + * `this` value for our property getter that we're working with. + * + * This function can return null on failure to allocate the object, throwing on + * the JSContext in the process. + * + * The isXray outparam will be set to true if obj is an Xray and false + * otherwise. + * + * Note that the Slow version should only be called from + * GetCachedSlotStorageObject. + */ +JSObject* GetCachedSlotStorageObjectSlow(JSContext* cx, + JS::Handle<JSObject*> obj, + bool* isXray); + +inline JSObject* GetCachedSlotStorageObject(JSContext* cx, + JS::Handle<JSObject*> obj, + bool* isXray) { + if (IsDOMObject(obj)) { + *isXray = false; + return obj; + } + + return GetCachedSlotStorageObjectSlow(cx, obj, isXray); +} + +extern NativePropertyHooks sEmptyNativePropertyHooks; + +extern const JSClassOps sBoringInterfaceObjectClassClassOps; + +extern const js::ObjectOps sInterfaceObjectClassObjectOps; + +inline bool UseDOMXray(JSObject* obj) { + const JSClass* clasp = JS::GetClass(obj); + return IsDOMClass(clasp) || JS_IsNativeFunction(obj, Constructor) || + IsDOMIfaceAndProtoClass(clasp); +} + +inline bool IsDOMConstructor(JSObject* obj) { + if (JS_IsNativeFunction(obj, dom::Constructor)) { + // LegacyFactoryFunction, like Image + return true; + } + + const JSClass* clasp = JS::GetClass(obj); + // Check for a DOM interface object. + return dom::IsDOMIfaceAndProtoClass(clasp) && + dom::DOMIfaceAndProtoJSClass::FromJSClass(clasp)->mType == + dom::eInterface; +} + +#ifdef DEBUG +inline bool HasConstructor(JSObject* obj) { + return JS_IsNativeFunction(obj, Constructor) || + JS::GetClass(obj)->getConstruct(); +} +#endif + +// Helpers for creating a const version of a type. +template <typename T> +const T& Constify(T& arg) { + return arg; +} + +// Helper for turning (Owning)NonNull<T> into T& +template <typename T> +T& NonNullHelper(T& aArg) { + return aArg; +} + +template <typename T> +T& NonNullHelper(NonNull<T>& aArg) { + return aArg; +} + +template <typename T> +const T& NonNullHelper(const NonNull<T>& aArg) { + return aArg; +} + +template <typename T> +T& NonNullHelper(OwningNonNull<T>& aArg) { + return aArg; +} + +template <typename T> +const T& NonNullHelper(const OwningNonNull<T>& aArg) { + return aArg; +} + +template <typename CharT> +inline void NonNullHelper(NonNull<binding_detail::FakeString<CharT>>& aArg) { + // This overload is here to make sure that we never end up applying + // NonNullHelper to a NonNull<binding_detail::FakeString>. If we + // try to, it should fail to compile, since presumably the caller will try to + // use our nonexistent return value. +} + +template <typename CharT> +inline void NonNullHelper( + const NonNull<binding_detail::FakeString<CharT>>& aArg) { + // This overload is here to make sure that we never end up applying + // NonNullHelper to a NonNull<binding_detail::FakeString>. If we + // try to, it should fail to compile, since presumably the caller will try to + // use our nonexistent return value. +} + +template <typename CharT> +inline void NonNullHelper(binding_detail::FakeString<CharT>& aArg) { + // This overload is here to make sure that we never end up applying + // NonNullHelper to a FakeString before we've constified it. If we + // try to, it should fail to compile, since presumably the caller will try to + // use our nonexistent return value. +} + +template <typename CharT> +MOZ_ALWAYS_INLINE const nsTSubstring<CharT>& NonNullHelper( + const binding_detail::FakeString<CharT>& aArg) { + return aArg; +} + +// Given a DOM reflector aObj, give its underlying DOM object a reflector in +// whatever global that underlying DOM object now thinks it should be in. If +// this is in a different compartment from aObj, aObj will become a +// cross-compatment wrapper for the new object. Otherwise, aObj will become the +// new object (via a brain transplant). If the new global is the same as the +// old global, we just keep using the same object. +// +// On entry to this method, aCx and aObj must be same-compartment. +void UpdateReflectorGlobal(JSContext* aCx, JS::Handle<JSObject*> aObj, + ErrorResult& aError); + +/** + * Used to implement the Symbol.hasInstance property of an interface object. + */ +bool InterfaceHasInstance(JSContext* cx, unsigned argc, JS::Value* vp); + +bool InterfaceHasInstance(JSContext* cx, int prototypeID, int depth, + JS::Handle<JSObject*> instance, bool* bp); + +// Used to implement the cross-context <Interface>.isInstance static method. +bool InterfaceIsInstance(JSContext* cx, unsigned argc, JS::Value* vp); + +// Helper for lenient getters/setters to report to console. If this +// returns false, we couldn't even get a global. +bool ReportLenientThisUnwrappingFailure(JSContext* cx, JSObject* obj); + +// Given a JSObject* that represents the chrome side of a JS-implemented WebIDL +// interface, get the nsIGlobalObject corresponding to the content side, if any. +// A false return means an exception was thrown. +bool GetContentGlobalForJSImplementedObject(BindingCallContext& cx, + JS::Handle<JSObject*> obj, + nsIGlobalObject** global); + +void ConstructJSImplementation(const char* aContractId, + nsIGlobalObject* aGlobal, + JS::MutableHandle<JSObject*> aObject, + ErrorResult& aRv); + +// XXX Avoid pulling in the whole ScriptSettings.h, however there should be a +// unique declaration of this function somewhere else. +JS::RootingContext* RootingCx(); + +template <typename T> +already_AddRefed<T> ConstructJSImplementation(const char* aContractId, + nsIGlobalObject* aGlobal, + ErrorResult& aRv) { + JS::RootingContext* cx = RootingCx(); + JS::Rooted<JSObject*> jsImplObj(cx); + ConstructJSImplementation(aContractId, aGlobal, &jsImplObj, aRv); + if (aRv.Failed()) { + return nullptr; + } + + MOZ_RELEASE_ASSERT(!js::IsWrapper(jsImplObj)); + JS::Rooted<JSObject*> jsImplGlobal(cx, JS::GetNonCCWObjectGlobal(jsImplObj)); + RefPtr<T> newObj = new T(jsImplObj, jsImplGlobal, aGlobal); + return newObj.forget(); +} + +template <typename T> +already_AddRefed<T> ConstructJSImplementation(const char* aContractId, + const GlobalObject& aGlobal, + ErrorResult& aRv) { + nsCOMPtr<nsIGlobalObject> global = do_QueryInterface(aGlobal.GetAsSupports()); + if (!global) { + aRv.Throw(NS_ERROR_FAILURE); + return nullptr; + } + + return ConstructJSImplementation<T>(aContractId, global, aRv); +} + +/** + * Convert an nsCString to jsval, returning true on success. + * These functions are intended for ByteString implementations. + * As such, the string is not UTF-8 encoded. Any UTF8 strings passed to these + * methods will be mangled. + */ +bool NonVoidByteStringToJsval(JSContext* cx, const nsACString& str, + JS::MutableHandle<JS::Value> rval); +inline bool ByteStringToJsval(JSContext* cx, const nsACString& str, + JS::MutableHandle<JS::Value> rval) { + if (str.IsVoid()) { + rval.setNull(); + return true; + } + return NonVoidByteStringToJsval(cx, str, rval); +} + +// Convert an utf-8 encoded nsCString to jsval, returning true on success. +// +// TODO(bug 1606957): This could probably be better. +inline bool NonVoidUTF8StringToJsval(JSContext* cx, const nsACString& str, + JS::MutableHandle<JS::Value> rval) { + JSString* jsStr = + JS_NewStringCopyUTF8N(cx, {str.BeginReading(), str.Length()}); + if (!jsStr) { + return false; + } + rval.setString(jsStr); + return true; +} + +inline bool UTF8StringToJsval(JSContext* cx, const nsACString& str, + JS::MutableHandle<JS::Value> rval) { + if (str.IsVoid()) { + rval.setNull(); + return true; + } + return NonVoidUTF8StringToJsval(cx, str, rval); +} + +template <class T, bool isISupports = std::is_base_of<nsISupports, T>::value> +struct PreserveWrapperHelper { + static void PreserveWrapper(T* aObject) { + aObject->PreserveWrapper(aObject, NS_CYCLE_COLLECTION_PARTICIPANT(T)); + } +}; + +template <class T> +struct PreserveWrapperHelper<T, true> { + static void PreserveWrapper(T* aObject) { + aObject->PreserveWrapper(reinterpret_cast<nsISupports*>(aObject)); + } +}; + +template <class T> +void PreserveWrapper(T* aObject) { + PreserveWrapperHelper<T>::PreserveWrapper(aObject); +} + +template <class T, bool isISupports = std::is_base_of<nsISupports, T>::value> +struct CastingAssertions { + static bool ToSupportsIsCorrect(T*) { return true; } + static bool ToSupportsIsOnPrimaryInheritanceChain(T*, nsWrapperCache*) { + return true; + } +}; + +template <class T> +struct CastingAssertions<T, true> { + static bool ToSupportsIsCorrect(T* aObject) { + return ToSupports(aObject) == reinterpret_cast<nsISupports*>(aObject); + } + static bool ToSupportsIsOnPrimaryInheritanceChain(T* aObject, + nsWrapperCache* aCache) { + return reinterpret_cast<void*>(aObject) != aCache; + } +}; + +template <class T> +bool ToSupportsIsCorrect(T* aObject) { + return CastingAssertions<T>::ToSupportsIsCorrect(aObject); +} + +template <class T> +bool ToSupportsIsOnPrimaryInheritanceChain(T* aObject, nsWrapperCache* aCache) { + return CastingAssertions<T>::ToSupportsIsOnPrimaryInheritanceChain(aObject, + aCache); +} + +// Get the size of allocated memory to associate with a binding JSObject for a +// native object. This is supplied to the JS engine to allow it to schedule GC +// when necessary. +// +// This function supplies a default value and is overloaded for specific native +// object types. +inline size_t BindingJSObjectMallocBytes(void* aNativePtr) { return 0; } + +// The BindingJSObjectCreator class is supposed to be used by a caller that +// wants to create and initialise a binding JSObject. After initialisation has +// been successfully completed it should call InitializationSucceeded(). +// The BindingJSObjectCreator object will root the JSObject until +// InitializationSucceeded() is called on it. If the native object for the +// binding is refcounted it will also hold a strong reference to it, that +// reference is transferred to the JSObject (which holds the native in a slot) +// when InitializationSucceeded() is called. If the BindingJSObjectCreator +// object is destroyed and InitializationSucceeded() was never called on it then +// the JSObject's slot holding the native will be set to undefined, and for a +// refcounted native the strong reference will be released. +template <class T> +class MOZ_STACK_CLASS BindingJSObjectCreator { + public: + explicit BindingJSObjectCreator(JSContext* aCx) : mReflector(aCx) {} + + ~BindingJSObjectCreator() { + if (mReflector) { + JS::SetReservedSlot(mReflector, DOM_OBJECT_SLOT, JS::UndefinedValue()); + } + } + + void CreateProxyObject(JSContext* aCx, const JSClass* aClass, + const DOMProxyHandler* aHandler, + JS::Handle<JSObject*> aProto, bool aLazyProto, + T* aNative, JS::Handle<JS::Value> aExpandoValue, + JS::MutableHandle<JSObject*> aReflector) { + js::ProxyOptions options; + options.setClass(aClass); + options.setLazyProto(aLazyProto); + + aReflector.set( + js::NewProxyObject(aCx, aHandler, aExpandoValue, aProto, options)); + if (aReflector) { + js::SetProxyReservedSlot(aReflector, DOM_OBJECT_SLOT, + JS::PrivateValue(aNative)); + mNative = aNative; + mReflector = aReflector; + + if (size_t mallocBytes = BindingJSObjectMallocBytes(aNative)) { + JS::AddAssociatedMemory(aReflector, mallocBytes, + JS::MemoryUse::DOMBinding); + } + } + } + + void CreateObject(JSContext* aCx, const JSClass* aClass, + JS::Handle<JSObject*> aProto, T* aNative, + JS::MutableHandle<JSObject*> aReflector) { + aReflector.set(JS_NewObjectWithGivenProto(aCx, aClass, aProto)); + if (aReflector) { + JS::SetReservedSlot(aReflector, DOM_OBJECT_SLOT, + JS::PrivateValue(aNative)); + mNative = aNative; + mReflector = aReflector; + + if (size_t mallocBytes = BindingJSObjectMallocBytes(aNative)) { + JS::AddAssociatedMemory(aReflector, mallocBytes, + JS::MemoryUse::DOMBinding); + } + } + } + + void InitializationSucceeded() { + T* pointer; + mNative.forget(&pointer); + mReflector = nullptr; + } + + private: + struct OwnedNative { + // Make sure the native objects inherit from NonRefcountedDOMObject so + // that we log their ctor and dtor. + static_assert(std::is_base_of<NonRefcountedDOMObject, T>::value, + "Non-refcounted objects with DOM bindings should inherit " + "from NonRefcountedDOMObject."); + + OwnedNative& operator=(T* aNative) { + mNative = aNative; + return *this; + } + + // This signature sucks, but it's the only one that will make a nsRefPtr + // just forget about its pointer without warning. + void forget(T** aResult) { + *aResult = mNative; + mNative = nullptr; + } + + // Keep track of the pointer for use in InitializationSucceeded(). + // The caller (or, after initialization succeeds, the JS object) retains + // ownership of the object. + T* mNative; + }; + + JS::Rooted<JSObject*> mReflector; + std::conditional_t<IsRefcounted<T>::value, RefPtr<T>, OwnedNative> mNative; +}; + +template <class T> +struct DeferredFinalizerImpl { + using SmartPtr = std::conditional_t< + std::is_same_v<T, nsISupports>, nsCOMPtr<T>, + std::conditional_t<IsRefcounted<T>::value, RefPtr<T>, UniquePtr<T>>>; + typedef SegmentedVector<SmartPtr> SmartPtrArray; + + static_assert( + std::is_same_v<T, nsISupports> || !std::is_base_of<nsISupports, T>::value, + "nsISupports classes should all use the nsISupports instantiation"); + + static inline void AppendAndTake( + SegmentedVector<nsCOMPtr<nsISupports>>& smartPtrArray, nsISupports* ptr) { + smartPtrArray.InfallibleAppend(dont_AddRef(ptr)); + } + template <class U> + static inline void AppendAndTake(SegmentedVector<RefPtr<U>>& smartPtrArray, + U* ptr) { + smartPtrArray.InfallibleAppend(dont_AddRef(ptr)); + } + template <class U> + static inline void AppendAndTake(SegmentedVector<UniquePtr<U>>& smartPtrArray, + U* ptr) { + smartPtrArray.InfallibleAppend(ptr); + } + + static void* AppendDeferredFinalizePointer(void* aData, void* aObject) { + SmartPtrArray* pointers = static_cast<SmartPtrArray*>(aData); + if (!pointers) { + pointers = new SmartPtrArray(); + } + AppendAndTake(*pointers, static_cast<T*>(aObject)); + return pointers; + } + static bool DeferredFinalize(uint32_t aSlice, void* aData) { + MOZ_ASSERT(aSlice > 0, "nonsensical/useless call with aSlice == 0"); + SmartPtrArray* pointers = static_cast<SmartPtrArray*>(aData); + uint32_t oldLen = pointers->Length(); + if (oldLen < aSlice) { + aSlice = oldLen; + } + uint32_t newLen = oldLen - aSlice; + pointers->PopLastN(aSlice); + if (newLen == 0) { + delete pointers; + return true; + } + return false; + } +}; + +template <class T, bool isISupports = std::is_base_of<nsISupports, T>::value> +struct DeferredFinalizer { + static void AddForDeferredFinalization(T* aObject) { + typedef DeferredFinalizerImpl<T> Impl; + DeferredFinalize(Impl::AppendDeferredFinalizePointer, + Impl::DeferredFinalize, aObject); + } +}; + +template <class T> +struct DeferredFinalizer<T, true> { + static void AddForDeferredFinalization(T* aObject) { + DeferredFinalize(reinterpret_cast<nsISupports*>(aObject)); + } +}; + +template <class T> +static void AddForDeferredFinalization(T* aObject) { + DeferredFinalizer<T>::AddForDeferredFinalization(aObject); +} + +// This returns T's CC participant if it participates in CC and does not inherit +// from nsISupports. Otherwise, it returns null. QI should be used to get the +// participant if T inherits from nsISupports. +template <class T, bool isISupports = std::is_base_of<nsISupports, T>::value> +class GetCCParticipant { + // Helper for GetCCParticipant for classes that participate in CC. + template <class U> + static constexpr nsCycleCollectionParticipant* GetHelper( + int, typename U::NS_CYCLE_COLLECTION_INNERCLASS* dummy = nullptr) { + return T::NS_CYCLE_COLLECTION_INNERCLASS::GetParticipant(); + } + // Helper for GetCCParticipant for classes that don't participate in CC. + template <class U> + static constexpr nsCycleCollectionParticipant* GetHelper(double) { + return nullptr; + } + + public: + static constexpr nsCycleCollectionParticipant* Get() { + // Passing int() here will try to call the GetHelper that takes an int as + // its first argument. If T doesn't participate in CC then substitution for + // the second argument (with a default value) will fail and because of + // SFINAE the next best match (the variant taking a double) will be called. + return GetHelper<T>(int()); + } +}; + +template <class T> +class GetCCParticipant<T, true> { + public: + static constexpr nsCycleCollectionParticipant* Get() { return nullptr; } +}; + +void FinalizeGlobal(JS::GCContext* aGcx, JSObject* aObj); + +bool ResolveGlobal(JSContext* aCx, JS::Handle<JSObject*> aObj, + JS::Handle<jsid> aId, bool* aResolvedp); + +bool MayResolveGlobal(const JSAtomState& aNames, jsid aId, JSObject* aMaybeObj); + +bool EnumerateGlobal(JSContext* aCx, JS::Handle<JSObject*> aObj, + JS::MutableHandleVector<jsid> aProperties, + bool aEnumerableOnly); + +struct CreateGlobalOptionsGeneric { + static void TraceGlobal(JSTracer* aTrc, JSObject* aObj) { + mozilla::dom::TraceProtoAndIfaceCache(aTrc, aObj); + } + static bool PostCreateGlobal(JSContext* aCx, JS::Handle<JSObject*> aGlobal) { + MOZ_ALWAYS_TRUE(TryPreserveWrapper(aGlobal)); + + return true; + } +}; + +struct CreateGlobalOptionsWithXPConnect { + static void TraceGlobal(JSTracer* aTrc, JSObject* aObj); + static bool PostCreateGlobal(JSContext* aCx, JS::Handle<JSObject*> aGlobal); +}; + +template <class T> +using IsGlobalWithXPConnect = + std::integral_constant<bool, + std::is_base_of<nsGlobalWindowInner, T>::value || + std::is_base_of<MessageManagerGlobal, T>::value>; + +template <class T> +struct CreateGlobalOptions + : std::conditional_t<IsGlobalWithXPConnect<T>::value, + CreateGlobalOptionsWithXPConnect, + CreateGlobalOptionsGeneric> { + static constexpr ProtoAndIfaceCache::Kind ProtoAndIfaceCacheKind = + ProtoAndIfaceCache::NonWindowLike; +}; + +template <> +struct CreateGlobalOptions<nsGlobalWindowInner> + : public CreateGlobalOptionsWithXPConnect { + static constexpr ProtoAndIfaceCache::Kind ProtoAndIfaceCacheKind = + ProtoAndIfaceCache::WindowLike; +}; + +uint64_t GetWindowID(void* aGlobal); +uint64_t GetWindowID(nsGlobalWindowInner* aGlobal); +uint64_t GetWindowID(DedicatedWorkerGlobalScope* aGlobal); + +// The return value is true if we created and successfully performed our part of +// the setup for the global, false otherwise. +// +// Typically this method's caller will want to ensure that +// xpc::InitGlobalObjectOptions is called before, and xpc::InitGlobalObject is +// called after, this method, to ensure that this global object and its +// compartment are consistent with other global objects. +template <class T, ProtoHandleGetter GetProto> +bool CreateGlobal(JSContext* aCx, T* aNative, nsWrapperCache* aCache, + const JSClass* aClass, JS::RealmOptions& aOptions, + JSPrincipals* aPrincipal, bool aInitStandardClasses, + JS::MutableHandle<JSObject*> aGlobal) { + aOptions.creationOptions() + .setTrace(CreateGlobalOptions<T>::TraceGlobal) + .setProfilerRealmID(GetWindowID(aNative)); + xpc::SetPrefableRealmOptions(aOptions); + + aGlobal.set(JS_NewGlobalObject(aCx, aClass, aPrincipal, + JS::DontFireOnNewGlobalHook, aOptions)); + if (!aGlobal) { + NS_WARNING("Failed to create global"); + return false; + } + + JSAutoRealm ar(aCx, aGlobal); + + { + JS::SetReservedSlot(aGlobal, DOM_OBJECT_SLOT, JS::PrivateValue(aNative)); + NS_ADDREF(aNative); + + aCache->SetWrapper(aGlobal); + + dom::AllocateProtoAndIfaceCache( + aGlobal, CreateGlobalOptions<T>::ProtoAndIfaceCacheKind); + + if (!CreateGlobalOptions<T>::PostCreateGlobal(aCx, aGlobal)) { + return false; + } + } + + if (aInitStandardClasses && !JS::InitRealmStandardClasses(aCx)) { + NS_WARNING("Failed to init standard classes"); + return false; + } + + JS::Handle<JSObject*> proto = GetProto(aCx); + if (!proto || !JS_SetPrototype(aCx, aGlobal, proto)) { + NS_WARNING("Failed to set proto"); + return false; + } + + bool succeeded; + if (!JS_SetImmutablePrototype(aCx, aGlobal, &succeeded)) { + return false; + } + MOZ_ASSERT(succeeded, + "making a fresh global object's [[Prototype]] immutable can " + "internally fail, but it should never be unsuccessful"); + + return true; +} + +namespace binding_detail { +/** + * WebIDL getters have a "generic" JSNative that is responsible for the + * following things: + * + * 1) Determining the "this" pointer for the C++ call. + * 2) Extracting the "specialized" getter from the jitinfo on the JSFunction. + * 3) Calling the specialized getter. + * 4) Handling exceptions as needed. + * + * There are several variants of (1) depending on the interface involved and + * there are two variants of (4) depending on whether the return type is a + * Promise. We handle this by templating our generic getter on a + * this-determination policy and an exception handling policy, then explicitly + * instantiating the relevant template specializations. + */ +template <typename ThisPolicy, typename ExceptionPolicy> +bool GenericGetter(JSContext* cx, unsigned argc, JS::Value* vp); + +/** + * WebIDL setters have a "generic" JSNative that is responsible for the + * following things: + * + * 1) Determining the "this" pointer for the C++ call. + * 2) Extracting the "specialized" setter from the jitinfo on the JSFunction. + * 3) Calling the specialized setter. + * + * There are several variants of (1) depending on the interface + * involved. We handle this by templating our generic setter on a + * this-determination policy, then explicitly instantiating the + * relevant template specializations. + */ +template <typename ThisPolicy> +bool GenericSetter(JSContext* cx, unsigned argc, JS::Value* vp); + +/** + * WebIDL methods have a "generic" JSNative that is responsible for the + * following things: + * + * 1) Determining the "this" pointer for the C++ call. + * 2) Extracting the "specialized" method from the jitinfo on the JSFunction. + * 3) Calling the specialized methodx. + * 4) Handling exceptions as needed. + * + * There are several variants of (1) depending on the interface involved and + * there are two variants of (4) depending on whether the return type is a + * Promise. We handle this by templating our generic method on a + * this-determination policy and an exception handling policy, then explicitly + * instantiating the relevant template specializations. + */ +template <typename ThisPolicy, typename ExceptionPolicy> +bool GenericMethod(JSContext* cx, unsigned argc, JS::Value* vp); + +// A this-extraction policy for normal getters/setters/methods. +struct NormalThisPolicy; + +// A this-extraction policy for getters/setters/methods on interfaces +// that are on some global's proto chain. +struct MaybeGlobalThisPolicy; + +// A this-extraction policy for lenient getters/setters. +struct LenientThisPolicy; + +// A this-extraction policy for cross-origin getters/setters/methods. +struct CrossOriginThisPolicy; + +// A this-extraction policy for getters/setters/methods that should +// not be allowed to be called cross-origin but expect objects that +// _can_ be cross-origin. +struct MaybeCrossOriginObjectThisPolicy; + +// A this-extraction policy which is just like +// MaybeCrossOriginObjectThisPolicy but has lenient-this behavior. +struct MaybeCrossOriginObjectLenientThisPolicy; + +// An exception-reporting policy for normal getters/setters/methods. +struct ThrowExceptions; + +// An exception-handling policy for Promise-returning getters/methods. +struct ConvertExceptionsToPromises; +} // namespace binding_detail + +bool StaticMethodPromiseWrapper(JSContext* cx, unsigned argc, JS::Value* vp); + +// ConvertExceptionToPromise should only be called when we have an error +// condition (e.g. returned false from a JSAPI method). Note that there may be +// no exception on cx, in which case this is an uncatchable failure that will +// simply be propagated. Otherwise this method will attempt to convert the +// exception to a Promise rejected with the exception that it will store in +// rval. +bool ConvertExceptionToPromise(JSContext* cx, + JS::MutableHandle<JS::Value> rval); + +#ifdef DEBUG +void AssertReturnTypeMatchesJitinfo(const JSJitInfo* aJitinfo, + JS::Handle<JS::Value> aValue); +#endif + +bool CallerSubsumes(JSObject* aObject); + +MOZ_ALWAYS_INLINE bool CallerSubsumes(JS::Handle<JS::Value> aValue) { + if (!aValue.isObject()) { + return true; + } + return CallerSubsumes(&aValue.toObject()); +} + +template <class T, class S> +inline RefPtr<T> StrongOrRawPtr(already_AddRefed<S>&& aPtr) { + return std::move(aPtr); +} + +template <class T, class S> +inline RefPtr<T> StrongOrRawPtr(RefPtr<S>&& aPtr) { + return std::move(aPtr); +} + +template <class T, class ReturnType = std::conditional_t<IsRefcounted<T>::value, + T*, UniquePtr<T>>> +inline ReturnType StrongOrRawPtr(T* aPtr) { + return ReturnType(aPtr); +} + +template <class T, template <typename> class SmartPtr, class S> +inline void StrongOrRawPtr(SmartPtr<S>&& aPtr) = delete; + +template <class T> +using StrongPtrForMember = + std::conditional_t<IsRefcounted<T>::value, RefPtr<T>, UniquePtr<T>>; + +namespace binding_detail { +inline JSObject* GetHackedNamespaceProtoObject(JSContext* aCx) { + return JS_NewPlainObject(aCx); +} +} // namespace binding_detail + +// Resolve an id on the given global object that wants to be included in +// Exposed=System webidl annotations. False return value means exception +// thrown. +bool SystemGlobalResolve(JSContext* cx, JS::Handle<JSObject*> obj, + JS::Handle<jsid> id, bool* resolvedp); + +// Enumerate all ids on the given global object that wants to be included in +// Exposed=System webidl annotations. False return value means exception +// thrown. +bool SystemGlobalEnumerate(JSContext* cx, JS::Handle<JSObject*> obj); + +// Slot indexes for maplike/setlike forEach functions +#define FOREACH_CALLBACK_SLOT 0 +#define FOREACH_MAPLIKEORSETLIKEOBJ_SLOT 1 + +// Backing function for running .forEach() on maplike/setlike interfaces. +// Unpacks callback and maplike/setlike object from reserved slots, then runs +// callback for each key (and value, for maplikes) +bool ForEachHandler(JSContext* aCx, unsigned aArgc, JS::Value* aVp); + +// Unpacks backing object (ES6 map/set) from the reserved slot of a reflector +// for a maplike/setlike interface. If backing object does not exist, creates +// backing object in the compartment of the reflector involved, making this safe +// to use across compartments/via xrays. Return values of these methods will +// always be in the context compartment. +bool GetMaplikeBackingObject(JSContext* aCx, JS::Handle<JSObject*> aObj, + size_t aSlotIndex, + JS::MutableHandle<JSObject*> aBackingObj, + bool* aBackingObjCreated); +bool GetSetlikeBackingObject(JSContext* aCx, JS::Handle<JSObject*> aObj, + size_t aSlotIndex, + JS::MutableHandle<JSObject*> aBackingObj, + bool* aBackingObjCreated); + +// Unpacks backing object (ES Proxy exotic object) from the reserved slot of a +// reflector for a observableArray attribute. If backing object does not exist, +// creates backing object in the compartment of the reflector involved, making +// this safe to use across compartments/via xrays. Return values of these +// methods will always be in the context compartment. +bool GetObservableArrayBackingObject( + JSContext* aCx, JS::Handle<JSObject*> aObj, size_t aSlotIndex, + JS::MutableHandle<JSObject*> aBackingObj, bool* aBackingObjCreated, + const ObservableArrayProxyHandler* aHandler, void* aOwner); + +// Get the desired prototype object for an object construction from the given +// CallArgs. The CallArgs must be for a constructor call. The +// aProtoId/aCreator arguments are used to get a default if we don't find a +// prototype on the newTarget of the callargs. +bool GetDesiredProto(JSContext* aCx, const JS::CallArgs& aCallArgs, + prototypes::id::ID aProtoId, + CreateInterfaceObjectsMethod aCreator, + JS::MutableHandle<JSObject*> aDesiredProto); + +// This function is expected to be called from the constructor function for an +// HTML or XUL element interface; the global/callargs need to be whatever was +// passed to that constructor function. +already_AddRefed<Element> CreateXULOrHTMLElement( + const GlobalObject& aGlobal, const JS::CallArgs& aCallArgs, + JS::Handle<JSObject*> aGivenProto, ErrorResult& aRv); + +void SetUseCounter(JSObject* aObject, UseCounter aUseCounter); +void SetUseCounter(UseCounterWorker aUseCounter); + +// Warnings +void DeprecationWarning(JSContext* aCx, JSObject* aObject, + DeprecatedOperations aOperation); + +void DeprecationWarning(const GlobalObject& aGlobal, + DeprecatedOperations aOperation); + +// A callback to perform funToString on an interface object +JSString* InterfaceObjectToString(JSContext* aCx, JS::Handle<JSObject*> aObject, + unsigned /* indent */); + +namespace binding_detail { +// Get a JS global object that can be used for some temporary allocations. The +// idea is that this should be used for situations when you need to operate in +// _some_ compartment but don't care which one. A typical example is when you +// have non-JS input, non-JS output, but have to go through some sort of JS +// representation in the middle, so need a compartment to allocate things in. +// +// It's VERY important that any consumers of this function only do things that +// are guaranteed to be side-effect-free, even in the face of a script +// environment controlled by a hostile adversary. This is because in the worker +// case the global is in fact the worker global, so it and its standard objects +// are controlled by the worker script. This is why this function is in the +// binding_detail namespace. Any use of this function MUST be very carefully +// reviewed by someone who is sufficiently devious and has a very good +// understanding of all the code that will run while we're using the return +// value, including the SpiderMonkey parts. +JSObject* UnprivilegedJunkScopeOrWorkerGlobal(const fallible_t&); + +// Implementation of the [HTMLConstructor] extended attribute. +bool HTMLConstructor(JSContext* aCx, unsigned aArgc, JS::Value* aVp, + constructors::id::ID aConstructorId, + prototypes::id::ID aProtoId, + CreateInterfaceObjectsMethod aCreator); + +// A method to test whether an attribute with the given JSJitGetterOp getter is +// enabled in the given set of prefable proeprty specs. For use for toJSON +// conversions. aObj is the object that would be used as the "this" value. +bool IsGetterEnabled(JSContext* aCx, JS::Handle<JSObject*> aObj, + JSJitGetterOp aGetter, + const Prefable<const JSPropertySpec>* aAttributes); + +// A class that can be used to examine the chars of a linear string. +class StringIdChars { + public: + // Require a non-const ref to an AutoRequireNoGC to prevent callers + // from passing temporaries. + StringIdChars(JS::AutoRequireNoGC& nogc, JSLinearString* str) { + mIsLatin1 = JS::LinearStringHasLatin1Chars(str); + if (mIsLatin1) { + mLatin1Chars = JS::GetLatin1LinearStringChars(nogc, str); + } else { + mTwoByteChars = JS::GetTwoByteLinearStringChars(nogc, str); + } +#ifdef DEBUG + mLength = JS::GetLinearStringLength(str); +#endif // DEBUG + } + + MOZ_ALWAYS_INLINE char16_t operator[](size_t index) { + MOZ_ASSERT(index < mLength); + if (mIsLatin1) { + return mLatin1Chars[index]; + } + return mTwoByteChars[index]; + } + + private: + bool mIsLatin1; + union { + const JS::Latin1Char* mLatin1Chars; + const char16_t* mTwoByteChars; + }; +#ifdef DEBUG + size_t mLength; +#endif // DEBUG +}; + +already_AddRefed<Promise> CreateRejectedPromiseFromThrownException( + JSContext* aCx, ErrorResult& aError); + +} // namespace binding_detail + +} // namespace dom +} // namespace mozilla + +#endif /* mozilla_dom_BindingUtils_h__ */ |