From 5f8de423f190bbb79a62f804151bc24824fa32d8 Mon Sep 17 00:00:00 2001 From: "Matt A. Tobin" Date: Fri, 2 Feb 2018 04:16:08 -0500 Subject: Add m-esr52 at 52.6.0 --- dom/bindings/DOMJSClass.h | 467 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 467 insertions(+) create mode 100644 dom/bindings/DOMJSClass.h (limited to 'dom/bindings/DOMJSClass.h') diff --git a/dom/bindings/DOMJSClass.h b/dom/bindings/DOMJSClass.h new file mode 100644 index 000000000..6e779840f --- /dev/null +++ b/dom/bindings/DOMJSClass.h @@ -0,0 +1,467 @@ +/* -*- 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_DOMJSClass_h +#define mozilla_dom_DOMJSClass_h + +#include "jsfriendapi.h" +#include "mozilla/Assertions.h" +#include "mozilla/Attributes.h" +#include "mozilla/Likely.h" + +#include "mozilla/dom/PrototypeList.h" // auto-generated + +#include "mozilla/dom/JSSlots.h" + +class nsCycleCollectionParticipant; + +// All DOM globals must have a slot at DOM_PROTOTYPE_SLOT. +#define DOM_PROTOTYPE_SLOT JSCLASS_GLOBAL_SLOT_COUNT + +// Keep this count up to date with any extra global slots added above. +#define DOM_GLOBAL_SLOTS 1 + +// We use these flag bits for the new bindings. +#define JSCLASS_DOM_GLOBAL JSCLASS_USERBIT1 +#define JSCLASS_IS_DOMIFACEANDPROTOJSCLASS JSCLASS_USERBIT2 + +namespace mozilla { +namespace dom { + +/** + * Returns true if code running in the given JSContext is allowed to access + * [SecureContext] API on the given JSObject. + * + * [SecureContext] API exposure is restricted to use by code in a Secure + * Contexts: + * + * https://w3c.github.io/webappsec-secure-contexts/ + * + * Since we want [SecureContext] exposure to depend on the privileges of the + * running code (rather than the privileges of an object's creator), this + * function checks to see whether the given JSContext's Compartment is flagged + * as a Secure Context. That allows us to make sure that system principal code + * (which is marked as a Secure Context) can access Secure Context API on an + * object in a different compartment, regardless of whether the other + * compartment is a Secure Context or not. + * + * Checking the JSContext's Compartment doesn't work for expanded principal + * globals accessing a Secure Context web page though (e.g. those used by frame + * scripts). To handle that we fall back to checking whether the JSObject came + * from a Secure Context. + * + * Note: We'd prefer this function to live in BindingUtils.h, but we need to + * call it in this header, and BindingUtils.h includes us (i.e. we'd have a + * circular dependency between headers if it lived there). + */ +inline bool +IsSecureContextOrObjectIsFromSecureContext(JSContext* aCx, JSObject* aObj) +{ + return JS::CompartmentCreationOptionsRef(js::GetContextCompartment(aCx)).secureContext() || + JS::CompartmentCreationOptionsRef(js::GetObjectCompartment(aObj)).secureContext(); +} + +typedef bool +(* ResolveOwnProperty)(JSContext* cx, JS::Handle wrapper, + JS::Handle obj, JS::Handle id, + JS::MutableHandle desc); + +typedef bool +(* EnumerateOwnProperties)(JSContext* cx, JS::Handle wrapper, + JS::Handle obj, + JS::AutoIdVector& props); + +typedef bool +(* DeleteNamedProperty)(JSContext* cx, JS::Handle wrapper, + JS::Handle obj, JS::Handle id, + JS::ObjectOpResult& opresult); + +// Returns true if the given global is of a type whose bit is set in +// aNonExposedGlobals. +bool +IsNonExposedGlobal(JSContext* aCx, JSObject* aGlobal, + uint32_t aNonExposedGlobals); + +struct ConstantSpec +{ + const char* name; + JS::Value value; +}; + +typedef bool (*PropertyEnabled)(JSContext* cx, JSObject* global); + +namespace GlobalNames { +// The names of our possible globals. These are the names of the actual +// interfaces, not of the global names used to refer to them in IDL [Exposed] +// annotations. +static const uint32_t Window = 1u << 0; +static const uint32_t BackstagePass = 1u << 1; +static const uint32_t DedicatedWorkerGlobalScope = 1u << 2; +static const uint32_t SharedWorkerGlobalScope = 1u << 3; +static const uint32_t ServiceWorkerGlobalScope = 1u << 4; +static const uint32_t WorkerDebuggerGlobalScope = 1u << 5; +static const uint32_t WorkletGlobalScope = 1u << 6; +} // namespace GlobalNames + +struct PrefableDisablers { + inline bool isEnabled(JSContext* cx, JS::Handle obj) const { + // Reading "enabled" on a worker thread is technically undefined behavior, + // because it's written only on main threads, with no barriers of any sort. + // So we want to avoid doing that. But we don't particularly want to make + // expensive NS_IsMainThread calls here. + // + // The good news is that "enabled" is only written for things that have a + // Pref annotation, and such things can never be exposed on non-Window + // globals; our IDL parser enforces that. So as long as we check our + // exposure set before checking "enabled" we will be ok. + if (nonExposedGlobals && + IsNonExposedGlobal(cx, js::GetGlobalForObjectCrossCompartment(obj), + nonExposedGlobals)) { + return false; + } + if (!enabled) { + return false; + } + if (secureContext && !IsSecureContextOrObjectIsFromSecureContext(cx, obj)) { + return false; + } + if (enabledFunc && + !enabledFunc(cx, js::GetGlobalForObjectCrossCompartment(obj))) { + return false; + } + return true; + } + + // A boolean indicating whether this set of specs is enabled. Not const + // because it will change at runtime if the corresponding pref is changed. + bool enabled; + + // A boolean indicating whether a Secure Context is required. + const bool secureContext; + + // Bitmask of global names that we should not be exposed in. + const uint16_t nonExposedGlobals; + + // A function pointer to a function that can say the property is disabled + // even if "enabled" is set to true. If the pointer is null the value of + // "enabled" is used as-is. + const PropertyEnabled enabledFunc; +}; + +template +struct Prefable { + inline bool isEnabled(JSContext* cx, JS::Handle obj) const { + if (MOZ_LIKELY(!disablers)) { + return true; + } + return disablers->isEnabled(cx, obj); + } + + // Things that can disable this set of specs. |nullptr| means "cannot be + // disabled". + PrefableDisablers* const disablers; + + // Array of specs, terminated in whatever way is customary for T. + // Null to indicate a end-of-array for Prefable, when such an + // indicator is needed. + const T* const specs; +}; + +// Conceptually, NativeProperties has seven (Prefable*, jsid*, T*) trios +// (where T is one of JSFunctionSpec, JSPropertySpec, or ConstantSpec), one for +// each of: static methods and attributes, methods and attributes, unforgeable +// methods and attributes, and constants. +// +// That's 21 pointers, but in most instances most of the trios are all null, +// and there are many instances. To save space we use a variable-length type, +// NativePropertiesN, to hold the data and getters to access it. It has N +// actual trios (stored in trios[]), plus four bits for each of the 7 possible +// trios: 1 bit that states if that trio is present, and 3 that state that +// trio's offset (if present) in trios[]. +// +// All trio accesses should be done via the getters, which contain assertions +// that check we don't overrun the end of the struct. (The trio data members are +// public only so they can be statically initialized.) These assertions should +// never fail so long as (a) accesses to the variable-length part are guarded by +// appropriate Has*() calls, and (b) all instances are well-formed, i.e. the +// value of N matches the number of mHas* members that are true. +// +// Finally, we define a typedef of NativePropertiesN<7>, NativeProperties, which +// we use as a "base" type used to refer to all instances of NativePropertiesN. +// (7 is used because that's the maximum valid parameter, though any other +// value 1..6 could also be used.) This is reasonable because of the +// aforementioned assertions in the getters. Upcast() is used to convert +// specific instances to this "base" type. +// +template +struct NativePropertiesN { + // Trio structs are stored in the trios[] array, and each element in the + // array could require a different T. Therefore, we can't use the correct + // type for mPrefables and mSpecs. Instead we use void* and cast to the + // correct type in the getters. + struct Trio { + const /*Prefable*/ void* const mPrefables; + const jsid* const mIds; + const /*T*/ void* const mSpecs; + }; + + const int32_t iteratorAliasMethodIndex; + + constexpr const NativePropertiesN<7>* Upcast() const { + return reinterpret_cast*>(this); + } + +#define DO(SpecT, FieldName) \ +public: \ + /* The bitfields indicating the trio's presence and (if present) offset. */ \ + const uint32_t mHas##FieldName##s:1; \ + const uint32_t m##FieldName##sOffset:3; \ +private: \ + const Trio* FieldName##sTrio() const { \ + MOZ_ASSERT(Has##FieldName##s()); \ + return &trios[m##FieldName##sOffset]; \ + } \ +public: \ + bool Has##FieldName##s() const { \ + return mHas##FieldName##s; \ + } \ + const Prefable* FieldName##s() const { \ + return static_cast*> \ + (FieldName##sTrio()->mPrefables); \ + } \ + const jsid* FieldName##Ids() const { \ + return FieldName##sTrio()->mIds; \ + } \ + const SpecT* FieldName##Specs() const { \ + return static_cast(FieldName##sTrio()->mSpecs); \ + } + + DO(JSFunctionSpec, StaticMethod) + DO(JSPropertySpec, StaticAttribute) + DO(JSFunctionSpec, Method) + DO(JSPropertySpec, Attribute) + DO(JSFunctionSpec, UnforgeableMethod) + DO(JSPropertySpec, UnforgeableAttribute) + DO(ConstantSpec, Constant) + +#undef DO + + const Trio trios[N]; +}; + +// Ensure the struct has the expected size. The 8 is for the +// iteratorAliasMethodIndex plus the bitfields; the rest is for trios[]. +static_assert(sizeof(NativePropertiesN<1>) == 8 + 3*sizeof(void*), "1 size"); +static_assert(sizeof(NativePropertiesN<2>) == 8 + 6*sizeof(void*), "2 size"); +static_assert(sizeof(NativePropertiesN<3>) == 8 + 9*sizeof(void*), "3 size"); +static_assert(sizeof(NativePropertiesN<4>) == 8 + 12*sizeof(void*), "4 size"); +static_assert(sizeof(NativePropertiesN<5>) == 8 + 15*sizeof(void*), "5 size"); +static_assert(sizeof(NativePropertiesN<6>) == 8 + 18*sizeof(void*), "6 size"); +static_assert(sizeof(NativePropertiesN<7>) == 8 + 21*sizeof(void*), "7 size"); + +// The "base" type. +typedef NativePropertiesN<7> NativeProperties; + +struct NativePropertiesHolder +{ + const NativeProperties* regular; + const NativeProperties* chromeOnly; +}; + +// Helper structure for Xrays for DOM binding objects. The same instance is used +// for instances, interface objects and interface prototype objects of a +// specific interface. +struct NativePropertyHooks +{ + // The hook to call for resolving indexed or named properties. May be null if + // there can't be any. + ResolveOwnProperty mResolveOwnProperty; + // The hook to call for enumerating indexed or named properties. May be null + // if there can't be any. + EnumerateOwnProperties mEnumerateOwnProperties; + // The hook to call to delete a named property. May be null if there are no + // named properties or no named property deleter. On success (true return) + // the "found" argument will be set to true if there was in fact such a named + // property and false otherwise. If it's set to false, the caller is expected + // to proceed with whatever deletion behavior it would have if there were no + // named properties involved at all (i.e. if the hook were null). If it's set + // to true, it will indicate via opresult whether the delete actually + // succeeded. + DeleteNamedProperty mDeleteNamedProperty; + + // The property arrays for this interface. + NativePropertiesHolder mNativeProperties; + + // This will be set to the ID of the interface prototype object for the + // interface, if it has one. If it doesn't have one it will be set to + // prototypes::id::_ID_Count. + prototypes::ID mPrototypeID; + + // This will be set to the ID of the interface object for the interface, if it + // has one. If it doesn't have one it will be set to + // constructors::id::_ID_Count. + constructors::ID mConstructorID; + + // The NativePropertyHooks instance for the parent interface (for + // ShimInterfaceInfo). + const NativePropertyHooks* mProtoHooks; + + // The JSClass to use for expandos on our Xrays. Can be null, in which case + // Xrays will use a default class of their choice. + const JSClass* mXrayExpandoClass; +}; + +enum DOMObjectType : uint8_t { + eInstance, + eGlobalInstance, + eInterface, + eInterfacePrototype, + eGlobalInterfacePrototype, + eNamedPropertiesObject +}; + +inline +bool +IsInstance(DOMObjectType type) +{ + return type == eInstance || type == eGlobalInstance; +} + +inline +bool +IsInterfacePrototype(DOMObjectType type) +{ + return type == eInterfacePrototype || type == eGlobalInterfacePrototype; +} + +typedef JSObject* (*AssociatedGlobalGetter)(JSContext* aCx, + JS::Handle aObj); + +typedef JSObject* (*ProtoGetter)(JSContext* aCx); + +/** + * Returns a handle to the relevant WebIDL prototype object for the current + * compartment global (which may be a handle to null on out of memory). Once + * allocated, the prototype object is guaranteed to exist as long as the global + * does, since the global traces its array of WebIDL prototypes and + * constructors. + */ +typedef JS::Handle (*ProtoHandleGetter)(JSContext* aCx); + +// Special JSClass for reflected DOM objects. +struct DOMJSClass +{ + // It would be nice to just inherit from JSClass, but that precludes pure + // compile-time initialization of the form |DOMJSClass = {...};|, since C++ + // only allows brace initialization for aggregate/POD types. + const js::Class mBase; + + // A list of interfaces that this object implements, in order of decreasing + // derivedness. + const prototypes::ID mInterfaceChain[MAX_PROTOTYPE_CHAIN_LENGTH]; + + // We store the DOM object in reserved slot with index DOM_OBJECT_SLOT or in + // the proxy private if we use a proxy object. + // Sometimes it's an nsISupports and sometimes it's not; this class tells + // us which it is. + const bool mDOMObjectIsISupports; + + const NativePropertyHooks* mNativeHooks; + + // A callback to find the associated global for our C++ object. Note that + // this is used in cases when that global is _changing_, so it will not match + // the global of the JSObject* passed in to this function! + AssociatedGlobalGetter mGetAssociatedGlobal; + ProtoHandleGetter mGetProto; + + // This stores the CC participant for the native, null if this class does not + // implement cycle collection or if it inherits from nsISupports (we can get + // the CC participant by QI'ing in that case). + nsCycleCollectionParticipant* mParticipant; + + static const DOMJSClass* FromJSClass(const JSClass* base) { + MOZ_ASSERT(base->flags & JSCLASS_IS_DOMJSCLASS); + return reinterpret_cast(base); + } + + static const DOMJSClass* FromJSClass(const js::Class* base) { + return FromJSClass(Jsvalify(base)); + } + + const JSClass* ToJSClass() const { return Jsvalify(&mBase); } +}; + +// Special JSClass for DOM interface and interface prototype objects. +struct DOMIfaceAndProtoJSClass +{ + // It would be nice to just inherit from js::Class, but that precludes pure + // compile-time initialization of the form + // |DOMJSInterfaceAndPrototypeClass = {...};|, since C++ only allows brace + // initialization for aggregate/POD types. + const js::Class mBase; + + // Either eInterface, eInterfacePrototype, eGlobalInterfacePrototype or + // eNamedPropertiesObject. + DOMObjectType mType; // uint8_t + + // Boolean indicating whether this object wants a @@hasInstance property + // pointing to InterfaceHasInstance defined on it. Only ever true for the + // eInterface case. + bool wantsInterfaceHasInstance; + + const prototypes::ID mPrototypeID; // uint16_t + const uint32_t mDepth; + + const NativePropertyHooks* mNativeHooks; + + // The value to return for toString() on this interface or interface prototype + // object. + const char* mToString; + + ProtoGetter mGetParentProto; + + static const DOMIfaceAndProtoJSClass* FromJSClass(const JSClass* base) { + MOZ_ASSERT(base->flags & JSCLASS_IS_DOMIFACEANDPROTOJSCLASS); + return reinterpret_cast(base); + } + static const DOMIfaceAndProtoJSClass* FromJSClass(const js::Class* base) { + return FromJSClass(Jsvalify(base)); + } + + const JSClass* ToJSClass() const { return Jsvalify(&mBase); } +}; + +class ProtoAndIfaceCache; + +inline bool +DOMGlobalHasProtoAndIFaceCache(JSObject* global) +{ + MOZ_ASSERT(js::GetObjectClass(global)->flags & JSCLASS_DOM_GLOBAL); + // This can be undefined if we GC while creating the global + return !js::GetReservedSlot(global, DOM_PROTOTYPE_SLOT).isUndefined(); +} + +inline bool +HasProtoAndIfaceCache(JSObject* global) +{ + if (!(js::GetObjectClass(global)->flags & JSCLASS_DOM_GLOBAL)) { + return false; + } + return DOMGlobalHasProtoAndIFaceCache(global); +} + +inline ProtoAndIfaceCache* +GetProtoAndIfaceCache(JSObject* global) +{ + MOZ_ASSERT(js::GetObjectClass(global)->flags & JSCLASS_DOM_GLOBAL); + return static_cast( + js::GetReservedSlot(global, DOM_PROTOTYPE_SLOT).toPrivate()); +} + +} // namespace dom +} // namespace mozilla + +#endif /* mozilla_dom_DOMJSClass_h */ -- cgit v1.2.3