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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * A header for declaring various things that binding implementation headers
+ * might need. The idea is to make binding implementation headers safe to
+ * include anywhere without running into include hell like we do with
+ * BindingUtils.h
+ */
+#ifndef mozilla_dom_BindingDeclarations_h__
+#define mozilla_dom_BindingDeclarations_h__
+
+#include "js/RootingAPI.h"
+#include "js/TypeDecls.h"
+
+#include "mozilla/Maybe.h"
+
+#include "mozilla/dom/DOMString.h"
+
+#include "nsCOMPtr.h"
+#include "nsString.h"
+#include "nsTArray.h"
+
+#include <type_traits>
+
+#include "js/Value.h"
+#include "mozilla/RootedOwningNonNull.h"
+#include "mozilla/RootedRefPtr.h"
+
+class nsIPrincipal;
+class nsWrapperCache;
+
+namespace mozilla {
+
+class ErrorResult;
+class OOMReporter;
+class CopyableErrorResult;
+
+namespace dom {
+
+class BindingCallContext;
+
+// Struct that serves as a base class for all dictionaries. Particularly useful
+// so we can use std::is_base_of to detect dictionary template arguments.
+struct DictionaryBase {
+ protected:
+ bool ParseJSON(JSContext* aCx, const nsAString& aJSON,
+ JS::MutableHandle<JS::Value> aVal);
+
+ bool StringifyToJSON(JSContext* aCx, JS::Handle<JSObject*> aObj,
+ nsAString& aJSON) const;
+
+ // Struct used as a way to force a dictionary constructor to not init the
+ // dictionary (via constructing from a pointer to this class). We're putting
+ // it here so that all the dictionaries will have access to it, but outside
+ // code will not.
+ struct FastDictionaryInitializer {};
+
+ bool mIsAnyMemberPresent = false;
+
+ private:
+ // aString is expected to actually be an nsAString*. Should only be
+ // called from StringifyToJSON.
+ static bool AppendJSONToString(const char16_t* aJSONData,
+ uint32_t aDataLength, void* aString);
+
+ public:
+ bool IsAnyMemberPresent() const { return mIsAnyMemberPresent; }
+};
+
+template <class T>
+constexpr bool is_dom_dictionary = std::is_base_of_v<DictionaryBase, T>;
+
+template <typename T>
+inline std::enable_if_t<is_dom_dictionary<T>, void> ImplCycleCollectionUnlink(
+ T& aDictionary) {
+ aDictionary.UnlinkForCC();
+}
+
+template <typename T>
+inline std::enable_if_t<is_dom_dictionary<T>, void> ImplCycleCollectionTraverse(
+ nsCycleCollectionTraversalCallback& aCallback, T& aDictionary,
+ const char* aName, uint32_t aFlags = 0) {
+ aDictionary.TraverseForCC(aCallback, aFlags);
+}
+
+template <typename T>
+inline std::enable_if_t<is_dom_dictionary<T>, void> ImplCycleCollectionUnlink(
+ UniquePtr<T>& aDictionary) {
+ aDictionary.reset();
+}
+
+template <typename T>
+inline std::enable_if_t<is_dom_dictionary<T>, void> ImplCycleCollectionTraverse(
+ nsCycleCollectionTraversalCallback& aCallback, UniquePtr<T>& aDictionary,
+ const char* aName, uint32_t aFlags = 0) {
+ if (aDictionary) {
+ ImplCycleCollectionTraverse(aCallback, *aDictionary, aName, aFlags);
+ }
+}
+// Struct that serves as a base class for all typed arrays and array buffers and
+// array buffer views. Particularly useful so we can use std::is_base_of to
+// detect typed array/buffer/view template arguments.
+struct AllTypedArraysBase {};
+
+template <class T>
+constexpr bool is_dom_typed_array = std::is_base_of_v<AllTypedArraysBase, T>;
+
+// Struct that serves as a base class for all unions.
+// Particularly useful so we can use std::is_base_of to detect union
+// template arguments.
+struct AllUnionBase {};
+
+template <class T>
+constexpr bool is_dom_union = std::is_base_of_v<AllUnionBase, T>;
+
+// Struct that serves as a base class for all owning unions.
+// Particularly useful so we can use std::is_base_of to detect owning union
+// template arguments.
+struct AllOwningUnionBase : public AllUnionBase {};
+
+template <class T>
+constexpr bool is_dom_owning_union = std::is_base_of_v<AllOwningUnionBase, T>;
+
+struct UnionWithTypedArraysBase {};
+
+template <class T>
+constexpr bool is_dom_union_with_typedarray_members =
+ std::is_base_of_v<UnionWithTypedArraysBase, T>;
+
+struct EnumEntry {
+ const char* value;
+ size_t length;
+};
+
+enum class CallerType : uint32_t;
+
+class MOZ_STACK_CLASS GlobalObject {
+ public:
+ GlobalObject(JSContext* aCx, JSObject* aObject);
+
+ JSObject* Get() const { return mGlobalJSObject; }
+
+ nsISupports* GetAsSupports() const;
+
+ // The context that this returns is not guaranteed to be in the compartment of
+ // the object returned from Get(), in fact it's generally in the caller's
+ // compartment.
+ JSContext* Context() const { return mCx; }
+
+ bool Failed() const { return !Get(); }
+
+ // It returns the subjectPrincipal if called on the main-thread, otherwise
+ // a nullptr is returned.
+ nsIPrincipal* GetSubjectPrincipal() const;
+
+ // Get the caller type. Note that this needs to be called before anyone has
+ // had a chance to mess with the JSContext.
+ dom::CallerType CallerType() const;
+
+ protected:
+ JS::Rooted<JSObject*> mGlobalJSObject;
+ JSContext* mCx;
+ mutable nsISupports* MOZ_UNSAFE_REF(
+ "Valid because GlobalObject is a stack "
+ "class, and mGlobalObject points to the "
+ "global, so it won't be destroyed as long "
+ "as GlobalObject lives on the stack") mGlobalObject;
+};
+
+// Class for representing optional arguments.
+template <typename T, typename InternalType>
+class Optional_base {
+ public:
+ Optional_base() = default;
+
+ Optional_base(Optional_base&&) = default;
+ Optional_base& operator=(Optional_base&&) = default;
+
+ explicit Optional_base(const T& aValue) { mImpl.emplace(aValue); }
+ explicit Optional_base(T&& aValue) { mImpl.emplace(std::move(aValue)); }
+
+ bool operator==(const Optional_base<T, InternalType>& aOther) const {
+ return mImpl == aOther.mImpl;
+ }
+
+ bool operator!=(const Optional_base<T, InternalType>& aOther) const {
+ return mImpl != aOther.mImpl;
+ }
+
+ template <typename T1, typename T2>
+ explicit Optional_base(const T1& aValue1, const T2& aValue2) {
+ mImpl.emplace(aValue1, aValue2);
+ }
+
+ bool WasPassed() const { return mImpl.isSome(); }
+
+ // Return InternalType here so we can work with it usefully.
+ template <typename... Args>
+ InternalType& Construct(Args&&... aArgs) {
+ mImpl.emplace(std::forward<Args>(aArgs)...);
+ return *mImpl;
+ }
+
+ void Reset() { mImpl.reset(); }
+
+ const T& Value() const { return *mImpl; }
+
+ // Return InternalType here so we can work with it usefully.
+ InternalType& Value() { return *mImpl; }
+
+ // And an explicit way to get the InternalType even if we're const.
+ const InternalType& InternalValue() const { return *mImpl; }
+
+ // If we ever decide to add conversion operators for optional arrays
+ // like the ones Nullable has, we'll need to ensure that Maybe<> has
+ // the boolean before the actual data.
+
+ private:
+ // Forbid copy-construction and assignment
+ Optional_base(const Optional_base& other) = delete;
+ const Optional_base& operator=(const Optional_base& other) = delete;
+
+ protected:
+ Maybe<InternalType> mImpl;
+};
+
+template <typename T>
+class Optional : public Optional_base<T, T> {
+ public:
+ MOZ_ALLOW_TEMPORARY Optional() : Optional_base<T, T>() {}
+
+ explicit Optional(const T& aValue) : Optional_base<T, T>(aValue) {}
+ Optional(Optional&&) = default;
+};
+
+template <typename T>
+class Optional<JS::Handle<T>>
+ : public Optional_base<JS::Handle<T>, JS::Rooted<T>> {
+ public:
+ MOZ_ALLOW_TEMPORARY Optional()
+ : Optional_base<JS::Handle<T>, JS::Rooted<T>>() {}
+
+ explicit Optional(JSContext* cx)
+ : Optional_base<JS::Handle<T>, JS::Rooted<T>>() {
+ this->Construct(cx);
+ }
+
+ Optional(JSContext* cx, const T& aValue)
+ : Optional_base<JS::Handle<T>, JS::Rooted<T>>(cx, aValue) {}
+
+ // Override the const Value() to return the right thing so we're not
+ // returning references to temporaries.
+ JS::Handle<T> Value() const { return *this->mImpl; }
+
+ // And we have to override the non-const one too, since we're
+ // shadowing the one on the superclass.
+ JS::Rooted<T>& Value() { return *this->mImpl; }
+};
+
+// A specialization of Optional for JSObject* to make sure that when someone
+// calls Construct() on it we will pre-initialized the JSObject* to nullptr so
+// it can be traced safely.
+template <>
+class Optional<JSObject*> : public Optional_base<JSObject*, JSObject*> {
+ public:
+ Optional() = default;
+
+ explicit Optional(JSObject* aValue)
+ : Optional_base<JSObject*, JSObject*>(aValue) {}
+
+ // Don't allow us to have an uninitialized JSObject*
+ JSObject*& Construct() {
+ // The Android compiler sucks and thinks we're trying to construct
+ // a JSObject* from an int if we don't cast here. :(
+ return Optional_base<JSObject*, JSObject*>::Construct(
+ static_cast<JSObject*>(nullptr));
+ }
+
+ template <class T1>
+ JSObject*& Construct(const T1& t1) {
+ return Optional_base<JSObject*, JSObject*>::Construct(t1);
+ }
+};
+
+// A specialization of Optional for JS::Value to make sure no one ever uses it.
+template <>
+class Optional<JS::Value> {
+ private:
+ Optional() = delete;
+
+ explicit Optional(const JS::Value& aValue) = delete;
+};
+
+// A specialization of Optional for NonNull that lets us get a T& from Value()
+template <typename U>
+class NonNull;
+template <typename T>
+class Optional<NonNull<T>> : public Optional_base<T, NonNull<T>> {
+ public:
+ // We want our Value to actually return a non-const reference, even
+ // if we're const. At least for things that are normally pointer
+ // types...
+ T& Value() const { return *this->mImpl->get(); }
+
+ // And we have to override the non-const one too, since we're
+ // shadowing the one on the superclass.
+ NonNull<T>& Value() { return *this->mImpl; }
+};
+
+// A specialization of Optional for OwningNonNull that lets us get a
+// T& from Value()
+template <typename T>
+class Optional<OwningNonNull<T>> : public Optional_base<T, OwningNonNull<T>> {
+ public:
+ // We want our Value to actually return a non-const reference, even
+ // if we're const. At least for things that are normally pointer
+ // types...
+ T& Value() const { return *this->mImpl->get(); }
+
+ // And we have to override the non-const one too, since we're
+ // shadowing the one on the superclass.
+ OwningNonNull<T>& Value() { return *this->mImpl; }
+};
+
+// Specialization for strings.
+// XXXbz we can't pull in FakeString here, because it depends on internal
+// strings. So we just have to forward-declare it and reimplement its
+// ToAStringPtr.
+
+namespace binding_detail {
+template <typename CharT>
+struct FakeString;
+} // namespace binding_detail
+
+template <typename CharT>
+class Optional<nsTSubstring<CharT>> {
+ using AString = nsTSubstring<CharT>;
+
+ public:
+ Optional() : mStr(nullptr) {}
+
+ bool WasPassed() const { return !!mStr; }
+
+ void operator=(const AString* str) {
+ MOZ_ASSERT(str);
+ mStr = str;
+ }
+
+ // If this code ever goes away, remove the comment pointing to it in the
+ // FakeString class in BindingUtils.h.
+ void operator=(const binding_detail::FakeString<CharT>* str) {
+ MOZ_ASSERT(str);
+ mStr = reinterpret_cast<const nsTString<CharT>*>(str);
+ }
+
+ const AString& Value() const {
+ MOZ_ASSERT(WasPassed());
+ return *mStr;
+ }
+
+ private:
+ // Forbid copy-construction and assignment
+ Optional(const Optional& other) = delete;
+ const Optional& operator=(const Optional& other) = delete;
+
+ const AString* mStr;
+};
+
+template <typename T>
+inline void ImplCycleCollectionUnlink(Optional<T>& aField) {
+ if (aField.WasPassed()) {
+ ImplCycleCollectionUnlink(aField.Value());
+ }
+}
+
+template <typename T>
+inline void ImplCycleCollectionTraverse(
+ nsCycleCollectionTraversalCallback& aCallback, Optional<T>& aField,
+ const char* aName, uint32_t aFlags = 0) {
+ if (aField.WasPassed()) {
+ ImplCycleCollectionTraverse(aCallback, aField.Value(), aName, aFlags);
+ }
+}
+
+template <class T>
+class NonNull {
+ public:
+ NonNull()
+#ifdef DEBUG
+ : inited(false)
+#endif
+ {
+ }
+
+ // This is no worse than get() in terms of const handling.
+ operator T&() const {
+ MOZ_ASSERT(inited);
+ MOZ_ASSERT(ptr, "NonNull<T> was set to null");
+ return *ptr;
+ }
+
+ operator T*() const {
+ MOZ_ASSERT(inited);
+ MOZ_ASSERT(ptr, "NonNull<T> was set to null");
+ return ptr;
+ }
+
+ void operator=(T* t) {
+ ptr = t;
+ MOZ_ASSERT(ptr);
+#ifdef DEBUG
+ inited = true;
+#endif
+ }
+
+ template <typename U>
+ void operator=(U* t) {
+ ptr = t->ToAStringPtr();
+ MOZ_ASSERT(ptr);
+#ifdef DEBUG
+ inited = true;
+#endif
+ }
+
+ T** Slot() {
+#ifdef DEBUG
+ inited = true;
+#endif
+ return &ptr;
+ }
+
+ T* Ptr() {
+ MOZ_ASSERT(inited);
+ MOZ_ASSERT(ptr, "NonNull<T> was set to null");
+ return ptr;
+ }
+
+ // Make us work with smart-ptr helpers that expect a get()
+ T* get() const {
+ MOZ_ASSERT(inited);
+ MOZ_ASSERT(ptr);
+ return ptr;
+ }
+
+ protected:
+ // ptr is left uninitialized for optimization purposes.
+ MOZ_INIT_OUTSIDE_CTOR T* ptr;
+#ifdef DEBUG
+ bool inited;
+#endif
+};
+
+// Class for representing sequences in arguments. We use a non-auto array
+// because that allows us to use sequences of sequences and the like. This
+// needs to be fallible because web content controls the length of the array,
+// and can easily try to create very large lengths.
+template <typename T>
+class Sequence : public FallibleTArray<T> {
+ public:
+ Sequence() : FallibleTArray<T>() {}
+ MOZ_IMPLICIT Sequence(FallibleTArray<T>&& aArray)
+ : FallibleTArray<T>(std::move(aArray)) {}
+ MOZ_IMPLICIT Sequence(nsTArray<T>&& aArray)
+ : FallibleTArray<T>(std::move(aArray)) {}
+
+ Sequence(Sequence&&) = default;
+ Sequence& operator=(Sequence&&) = default;
+
+ // XXX(Bug 1631461) Codegen.py must be adapted to allow making Sequence
+ // uncopyable.
+ Sequence(const Sequence& aOther) {
+ if (!this->AppendElements(aOther, fallible)) {
+ MOZ_CRASH("Out of memory");
+ }
+ }
+ Sequence& operator=(const Sequence& aOther) {
+ if (this != &aOther) {
+ this->Clear();
+ if (!this->AppendElements(aOther, fallible)) {
+ MOZ_CRASH("Out of memory");
+ }
+ }
+ return *this;
+ }
+};
+
+inline nsWrapperCache* GetWrapperCache(nsWrapperCache* cache) { return cache; }
+
+inline nsWrapperCache* GetWrapperCache(void* p) { return nullptr; }
+
+// Helper template for smart pointers to resolve ambiguity between
+// GetWrappeCache(void*) and GetWrapperCache(const ParentObject&).
+template <template <typename> class SmartPtr, typename T>
+inline nsWrapperCache* GetWrapperCache(const SmartPtr<T>& aObject) {
+ return GetWrapperCache(aObject.get());
+}
+
+enum class ReflectionScope { Content, NAC, UAWidget };
+
+struct MOZ_STACK_CLASS ParentObject {
+ template <class T>
+ MOZ_IMPLICIT ParentObject(T* aObject)
+ : mObject(ToSupports(aObject)),
+ mWrapperCache(GetWrapperCache(aObject)),
+ mReflectionScope(ReflectionScope::Content) {}
+
+ template <class T, template <typename> class SmartPtr>
+ MOZ_IMPLICIT ParentObject(const SmartPtr<T>& aObject)
+ : mObject(aObject.get()),
+ mWrapperCache(GetWrapperCache(aObject.get())),
+ mReflectionScope(ReflectionScope::Content) {}
+
+ ParentObject(nsISupports* aObject, nsWrapperCache* aCache)
+ : mObject(aObject),
+ mWrapperCache(aCache),
+ mReflectionScope(ReflectionScope::Content) {}
+
+ // We don't want to make this an nsCOMPtr because of performance reasons, but
+ // it's safe because ParentObject is a stack class.
+ nsISupports* const MOZ_NON_OWNING_REF mObject;
+ nsWrapperCache* const mWrapperCache;
+ ReflectionScope mReflectionScope;
+};
+
+namespace binding_detail {
+
+// Class for simple sequence arguments, only used internally by codegen.
+template <typename T>
+class AutoSequence : public AutoTArray<T, 16> {
+ public:
+ AutoSequence() : AutoTArray<T, 16>() {}
+
+ // Allow converting to const sequences as needed
+ operator const Sequence<T>&() const {
+ return *reinterpret_cast<const Sequence<T>*>(this);
+ }
+};
+
+} // namespace binding_detail
+
+// Enum to represent a system or non-system caller type.
+enum class CallerType : uint32_t { System, NonSystem };
+
+// A class that can be passed (by value or const reference) to indicate that the
+// caller is always a system caller. This can be used as the type of an
+// argument to force only system callers to call a function.
+class SystemCallerGuarantee {
+ public:
+ operator CallerType() const { return CallerType::System; }
+};
+
+class ProtoAndIfaceCache;
+typedef void (*CreateInterfaceObjectsMethod)(JSContext* aCx,
+ JS::Handle<JSObject*> aGlobal,
+ ProtoAndIfaceCache& aCache,
+ bool aDefineOnGlobal);
+JS::Handle<JSObject*> GetPerInterfaceObjectHandle(
+ JSContext* aCx, size_t aSlotId, CreateInterfaceObjectsMethod aCreator,
+ bool aDefineOnGlobal);
+
+} // namespace dom
+} // namespace mozilla
+
+#endif // mozilla_dom_BindingDeclarations_h__
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