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Diffstat (limited to 'dom/bindings/ToJSValue.h')
| -rw-r--r-- | dom/bindings/ToJSValue.h | 486 |
1 files changed, 486 insertions, 0 deletions
diff --git a/dom/bindings/ToJSValue.h b/dom/bindings/ToJSValue.h new file mode 100644 index 0000000000..e81ea41e39 --- /dev/null +++ b/dom/bindings/ToJSValue.h @@ -0,0 +1,486 @@ +/* -*- 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_ToJSValue_h +#define mozilla_dom_ToJSValue_h + +#include <cstddef> // for size_t +#include <cstdint> // for int32_t, int64_t, uint32_t, uint64_t +#include <type_traits> // for is_base_of, enable_if_t, enable_if, is_pointer, is_same, void_t +#include <utility> // for forward +#include "ErrorList.h" // for nsresult +#include "js/Array.h" // for NewArrayObject +#include "js/GCVector.h" // for RootedVector, MutableWrappedPtrOperations +#include "js/PropertyAndElement.h" // JS_DefineUCProperty +#include "js/RootingAPI.h" // for MutableHandle, Rooted, Handle, Heap +#include "js/Value.h" // for Value +#include "js/ValueArray.h" // for HandleValueArray +#include "jsapi.h" // for CurrentGlobalOrNull +#include "mozilla/Assertions.h" // for AssertionConditionType, MOZ_ASSERT, MOZ_ASSERT_HELPER1 +#include "mozilla/UniquePtr.h" // for UniquePtr +#include "mozilla/Unused.h" // for Unused +#include "mozilla/dom/BindingUtils.h" // for MaybeWrapValue, MaybeWrapObjectOrNullValue, XPCOMObjectToJsval, GetOrCreateDOMReflector +#include "mozilla/dom/CallbackObject.h" // for CallbackObject +#include "mozilla/dom/Record.h" +#include "nsID.h" // for NS_GET_TEMPLATE_IID, nsIID +#include "nsISupports.h" // for nsISupports +#include "nsStringFwd.h" // for nsAString +#include "nsTArrayForwardDeclare.h" +#include "xpcObjectHelper.h" // for xpcObjectHelper + +namespace mozilla::dom { + +class CallbackObject; +class Promise; +class WindowProxyHolder; +template <typename TypedArrayType> +class TypedArrayCreator; + +// If ToJSValue returns false, it must set an exception on the +// JSContext. + +// Accept strings. +[[nodiscard]] bool ToJSValue(JSContext* aCx, const nsAString& aArgument, + JS::MutableHandle<JS::Value> aValue); + +// Treats the input as UTF-8, and throws otherwise. +[[nodiscard]] bool ToJSValue(JSContext* aCx, const nsACString& aArgument, + JS::MutableHandle<JS::Value> aValue); + +// Accept booleans. But be careful here: if we just have a function that takes +// a boolean argument, then any pointer that doesn't match one of our other +// signatures/templates will get treated as a boolean, which is clearly not +// desirable. So make this a template that only gets used if the argument type +// is actually boolean +template <typename T> +[[nodiscard]] std::enable_if_t<std::is_same<T, bool>::value, bool> ToJSValue( + JSContext* aCx, T aArgument, JS::MutableHandle<JS::Value> aValue) { + // Make sure we're called in a compartment + MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx)); + + aValue.setBoolean(aArgument); + return true; +} + +// Accept integer types +inline bool ToJSValue(JSContext* aCx, int32_t aArgument, + JS::MutableHandle<JS::Value> aValue) { + // Make sure we're called in a compartment + MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx)); + + aValue.setInt32(aArgument); + return true; +} + +inline bool ToJSValue(JSContext* aCx, uint32_t aArgument, + JS::MutableHandle<JS::Value> aValue) { + // Make sure we're called in a compartment + MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx)); + + aValue.setNumber(aArgument); + return true; +} + +inline bool ToJSValue(JSContext* aCx, int64_t aArgument, + JS::MutableHandle<JS::Value> aValue) { + // Make sure we're called in a compartment + MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx)); + + aValue.setNumber(double(aArgument)); + return true; +} + +inline bool ToJSValue(JSContext* aCx, uint64_t aArgument, + JS::MutableHandle<JS::Value> aValue) { + // Make sure we're called in a compartment + MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx)); + + aValue.setNumber(double(aArgument)); + return true; +} + +// accept floating point types +inline bool ToJSValue(JSContext* aCx, float aArgument, + JS::MutableHandle<JS::Value> aValue) { + // Make sure we're called in a compartment + MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx)); + + aValue.setNumber(aArgument); + return true; +} + +inline bool ToJSValue(JSContext* aCx, double aArgument, + JS::MutableHandle<JS::Value> aValue) { + // Make sure we're called in a compartment + MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx)); + + aValue.set(JS_NumberValue(aArgument)); + return true; +} + +// Accept CallbackObjects +[[nodiscard]] inline bool ToJSValue(JSContext* aCx, CallbackObject& aArgument, + JS::MutableHandle<JS::Value> aValue) { + // Make sure we're called in a compartment + MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx)); + + aValue.setObjectOrNull(aArgument.Callback(aCx)); + + return MaybeWrapValue(aCx, aValue); +} + +// Accept objects that inherit from nsWrapperCache (e.g. most +// DOM objects). +template <class T> +[[nodiscard]] std::enable_if_t<std::is_base_of<nsWrapperCache, T>::value, bool> +ToJSValue(JSContext* aCx, T& aArgument, JS::MutableHandle<JS::Value> aValue) { + // Make sure we're called in a compartment + MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx)); + + return GetOrCreateDOMReflector(aCx, aArgument, aValue); +} + +// Accept non-refcounted DOM objects that do not inherit from +// nsWrapperCache. Refcounted ones would be too much of a footgun: +// you could convert them to JS twice and get two different objects. +namespace binding_detail { +template <class T> +[[nodiscard]] std::enable_if_t< + std::is_base_of<NonRefcountedDOMObject, T>::value, bool> +ToJSValueFromPointerHelper(JSContext* aCx, T* aArgument, + JS::MutableHandle<JS::Value> aValue) { + // Make sure we're called in a compartment + MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx)); + + // This is a cut-down version of + // WrapNewBindingNonWrapperCachedObject that doesn't need to deal + // with nearly as many cases. + if (!aArgument) { + aValue.setNull(); + return true; + } + + JS::Rooted<JSObject*> obj(aCx); + if (!aArgument->WrapObject(aCx, nullptr, &obj)) { + return false; + } + + aValue.setObject(*obj); + return true; +} +} // namespace binding_detail + +// We can take a non-refcounted non-wrapper-cached DOM object that lives in a +// UniquePtr. +template <class T> +[[nodiscard]] std::enable_if_t< + std::is_base_of<NonRefcountedDOMObject, T>::value, bool> +ToJSValue(JSContext* aCx, UniquePtr<T>&& aArgument, + JS::MutableHandle<JS::Value> aValue) { + if (!binding_detail::ToJSValueFromPointerHelper(aCx, aArgument.get(), + aValue)) { + return false; + } + + // JS object took ownership + Unused << aArgument.release(); + return true; +} + +// Accept typed arrays built from appropriate nsTArray values +template <typename T> +[[nodiscard]] +typename std::enable_if<std::is_base_of<AllTypedArraysBase, T>::value, + bool>::type +ToJSValue(JSContext* aCx, const TypedArrayCreator<T>& aArgument, + JS::MutableHandle<JS::Value> aValue) { + // Make sure we're called in a compartment + MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx)); + + JSObject* obj = aArgument.Create(aCx); + if (!obj) { + return false; + } + aValue.setObject(*obj); + return true; +} + +namespace binding_detail { +// Helper type alias for picking a script-exposable non-wrappercached XPIDL +// interface to expose to JS code. Falls back to `nsISupports` if the specific +// interface type is ambiguous. +template <typename T, typename = void> +struct GetScriptableInterfaceType { + using Type = nsISupports; + + static_assert(std::is_base_of_v<nsISupports, T>, + "T must inherit from nsISupports"); +}; +template <typename T> +struct GetScriptableInterfaceType< + T, std::void_t<typename T::ScriptableInterfaceType>> { + using Type = typename T::ScriptableInterfaceType; + + static_assert(std::is_base_of_v<Type, T>, + "T must inherit from ScriptableInterfaceType"); + static_assert(std::is_base_of_v<nsISupports, Type>, + "ScriptableInterfaceType must inherit from nsISupports"); +}; + +template <typename T> +using ScriptableInterfaceType = typename GetScriptableInterfaceType<T>::Type; +} // namespace binding_detail + +// Accept objects that inherit from nsISupports but not nsWrapperCache (e.g. +// DOM File). +template <class T> +[[nodiscard]] std::enable_if_t<!std::is_base_of<nsWrapperCache, T>::value && + !std::is_base_of<CallbackObject, T>::value && + std::is_base_of<nsISupports, T>::value, + bool> +ToJSValue(JSContext* aCx, T& aArgument, JS::MutableHandle<JS::Value> aValue) { + // Make sure we're called in a compartment + MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx)); + + xpcObjectHelper helper(ToSupports(&aArgument)); + JS::Rooted<JSObject*> scope(aCx, JS::CurrentGlobalOrNull(aCx)); + const nsIID& iid = + NS_GET_TEMPLATE_IID(binding_detail::ScriptableInterfaceType<T>); + return XPCOMObjectToJsval(aCx, scope, helper, &iid, true, aValue); +} + +[[nodiscard]] bool ToJSValue(JSContext* aCx, const WindowProxyHolder& aArgument, + JS::MutableHandle<JS::Value> aValue); + +// Accept nsRefPtr/nsCOMPtr +template <typename T> +[[nodiscard]] bool ToJSValue(JSContext* aCx, const nsCOMPtr<T>& aArgument, + JS::MutableHandle<JS::Value> aValue) { + return ToJSValue(aCx, *aArgument.get(), aValue); +} + +template <typename T> +[[nodiscard]] bool ToJSValue(JSContext* aCx, const RefPtr<T>& aArgument, + JS::MutableHandle<JS::Value> aValue) { + return ToJSValue(aCx, *aArgument.get(), aValue); +} + +template <typename T> +[[nodiscard]] bool ToJSValue(JSContext* aCx, const NonNull<T>& aArgument, + JS::MutableHandle<JS::Value> aValue) { + return ToJSValue(aCx, *aArgument.get(), aValue); +} + +template <typename T> +[[nodiscard]] bool ToJSValue(JSContext* aCx, const OwningNonNull<T>& aArgument, + JS::MutableHandle<JS::Value> aValue) { + return ToJSValue(aCx, *aArgument.get(), aValue); +} + +// Accept WebIDL dictionaries +template <class T> +[[nodiscard]] std::enable_if_t<std::is_base_of<DictionaryBase, T>::value, bool> +ToJSValue(JSContext* aCx, const T& aArgument, + JS::MutableHandle<JS::Value> aValue) { + return aArgument.ToObjectInternal(aCx, aValue); +} + +// Accept existing JS values (which may not be same-compartment with us +[[nodiscard]] inline bool ToJSValue(JSContext* aCx, const JS::Value& aArgument, + JS::MutableHandle<JS::Value> aValue) { + aValue.set(aArgument); + return MaybeWrapValue(aCx, aValue); +} +[[nodiscard]] inline bool ToJSValue(JSContext* aCx, + JS::Handle<JS::Value> aArgument, + JS::MutableHandle<JS::Value> aValue) { + aValue.set(aArgument); + return MaybeWrapValue(aCx, aValue); +} + +// Accept existing JS values on the Heap (which may not be same-compartment with +// us +[[nodiscard]] inline bool ToJSValue(JSContext* aCx, + const JS::Heap<JS::Value>& aArgument, + JS::MutableHandle<JS::Value> aValue) { + aValue.set(aArgument); + return MaybeWrapValue(aCx, aValue); +} + +// Accept existing rooted JS values (which may not be same-compartment with us +[[nodiscard]] inline bool ToJSValue(JSContext* aCx, + const JS::Rooted<JS::Value>& aArgument, + JS::MutableHandle<JS::Value> aValue) { + aValue.set(aArgument); + return MaybeWrapValue(aCx, aValue); +} + +// Accept existing rooted JS objects (which may not be same-compartment with +// us). +[[nodiscard]] inline bool ToJSValue(JSContext* aCx, + const JS::Rooted<JSObject*>& aArgument, + JS::MutableHandle<JS::Value> aValue) { + aValue.setObjectOrNull(aArgument); + return MaybeWrapObjectOrNullValue(aCx, aValue); +} + +// Accept nsresult, for use in rejections, and create an XPCOM +// exception object representing that nsresult. +[[nodiscard]] bool ToJSValue(JSContext* aCx, nsresult aArgument, + JS::MutableHandle<JS::Value> aValue); + +// Accept ErrorResult, for use in rejections, and create an exception +// representing the failure. Note, the ErrorResult must indicate a failure +// with aArgument.Failure() returning true. +[[nodiscard]] bool ToJSValue(JSContext* aCx, ErrorResult&& aArgument, + JS::MutableHandle<JS::Value> aValue); + +// Accept owning WebIDL unions. +template <typename T> +[[nodiscard]] std::enable_if_t<std::is_base_of<AllOwningUnionBase, T>::value, + bool> +ToJSValue(JSContext* aCx, const T& aArgument, + JS::MutableHandle<JS::Value> aValue) { + JS::Rooted<JSObject*> global(aCx, JS::CurrentGlobalOrNull(aCx)); + return aArgument.ToJSVal(aCx, global, aValue); +} + +// Accept pointers to other things we accept +template <typename T> +[[nodiscard]] std::enable_if_t<std::is_pointer<T>::value, bool> ToJSValue( + JSContext* aCx, T aArgument, JS::MutableHandle<JS::Value> aValue) { + return ToJSValue(aCx, *aArgument, aValue); +} + +// Accept Promise objects, which need special handling. +[[nodiscard]] bool ToJSValue(JSContext* aCx, Promise& aArgument, + JS::MutableHandle<JS::Value> aValue); + +// Accept arrays (and nested arrays) of other things we accept +template <typename T> +[[nodiscard]] bool ToJSValue(JSContext* aCx, T* aArguments, size_t aLength, + JS::MutableHandle<JS::Value> aValue); + +template <typename T> +[[nodiscard]] bool ToJSValue(JSContext* aCx, const nsTArray<T>& aArgument, + JS::MutableHandle<JS::Value> aValue) { + return ToJSValue(aCx, aArgument.Elements(), aArgument.Length(), aValue); +} + +template <typename T> +[[nodiscard]] bool ToJSValue(JSContext* aCx, const FallibleTArray<T>& aArgument, + JS::MutableHandle<JS::Value> aValue) { + return ToJSValue(aCx, aArgument.Elements(), aArgument.Length(), aValue); +} + +template <typename T, int N> +[[nodiscard]] bool ToJSValue(JSContext* aCx, const T (&aArgument)[N], + JS::MutableHandle<JS::Value> aValue) { + return ToJSValue(aCx, aArgument, N, aValue); +} + +// Accept arrays of other things we accept +template <typename T> +[[nodiscard]] bool ToJSValue(JSContext* aCx, T* aArguments, size_t aLength, + JS::MutableHandle<JS::Value> aValue) { + // Make sure we're called in a compartment + MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx)); + + JS::RootedVector<JS::Value> v(aCx); + if (!v.resize(aLength)) { + return false; + } + for (size_t i = 0; i < aLength; ++i) { + if (!ToJSValue(aCx, aArguments[i], v[i])) { + return false; + } + } + JSObject* arrayObj = JS::NewArrayObject(aCx, v); + if (!arrayObj) { + return false; + } + aValue.setObject(*arrayObj); + return true; +} + +// Accept tuple of other things we accept. The result will be a JS array object. +template <typename... Elements> +[[nodiscard]] bool ToJSValue(JSContext* aCx, + const std::tuple<Elements...>& aArguments, + JS::MutableHandle<JS::Value> aValue) { + // Make sure we're called in a compartment + MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx)); + + JS::RootedVector<JS::Value> v(aCx); + if (!v.resize(sizeof...(Elements))) { + return false; + } + bool ok = true; + size_t i = 0; + auto Callable = [aCx, &ok, &v, &i](auto& aElem) { + ok = ok && ToJSValue(aCx, aElem, v[i++]); + }; + std::apply([Callable](auto&&... args) { (Callable(args), ...); }, aArguments); + + if (!ok) { + return false; + } + JSObject* arrayObj = JS::NewArrayObject(aCx, v); + if (!arrayObj) { + return false; + } + aValue.setObject(*arrayObj); + return true; +} + +// Accept records of other things we accept. N.B. This assumes that +// keys are either UTF-8 or UTF-16-ish. See Bug 1706058. +template <typename K, typename V> +[[nodiscard]] bool ToJSValue(JSContext* aCx, const Record<K, V>& aArgument, + JS::MutableHandle<JS::Value> aValue) { + JS::Rooted<JSObject*> recordObj(aCx, JS_NewPlainObject(aCx)); + if (!recordObj) { + return false; + } + + for (auto& entry : aArgument.Entries()) { + JS::Rooted<JS::Value> value(aCx); + if (!ToJSValue(aCx, entry.mValue, &value)) { + return false; + } + + if constexpr (std::is_same_v<nsCString, decltype(entry.mKey)>) { + NS_ConvertUTF8toUTF16 expandedKey(entry.mKey); + if (!JS_DefineUCProperty(aCx, recordObj, expandedKey.BeginReading(), + expandedKey.Length(), value, JSPROP_ENUMERATE)) { + return false; + } + } else { + if (!JS_DefineUCProperty(aCx, recordObj, entry.mKey.BeginReading(), + entry.mKey.Length(), value, JSPROP_ENUMERATE)) { + return false; + } + } + } + + aValue.setObject(*recordObj); + return true; +} + +template <typename T> +[[nodiscard]] bool ToJSValue(JSContext* aCx, const Nullable<T>& aArgument, + JS::MutableHandle<JS::Value> aValue) { + if (aArgument.IsNull()) { + aValue.setNull(); + return true; + } + + return ToJSValue(aCx, aArgument.Value(), aValue); +} + +} // namespace mozilla::dom + +#endif /* mozilla_dom_ToJSValue_h */ |