/* * Copyright (C) 2017 Apple Inc. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF * THE POSSIBILITY OF SUCH DAMAGE. */ #pragma once #include "JSDOMConvertStrings.h" namespace WebCore { // Implementations of the abstract operations defined at // https://heycam.github.io/webidl/#legacy-platform-object-abstract-ops enum class OverrideBuiltins { No, Yes }; // An implementation of the 'named property visibility algorithm' // https://heycam.github.io/webidl/#dfn-named-property-visibility template<OverrideBuiltins overrideBuiltins, class JSClass> static bool isVisibleNamedProperty(JSC::JSGlobalObject& lexicalGlobalObject, JSClass& thisObject, JSC::PropertyName propertyName) { // FIXME: It seems unfortunate that have to do two lookups for the property name, // one for isSupportedPropertyName and one by the user of this algorithm to access // that property. It would be nice if we could smuggle the result, or an iterator // out so the duplicate lookup could be avoided. // NOTE: While it is not specified, a Symbol can never be a 'supported property // name' so we check that first. if (propertyName.isSymbol()) return false; auto& impl = thisObject.wrapped(); // 1. If P is not a supported property name of O, then return false. if (!impl.isSupportedPropertyName(propertyNameToString(propertyName))) return false; // 2. If O has an own property named P, then return false. JSC::PropertySlot slot { &thisObject, JSC::PropertySlot::InternalMethodType::VMInquiry, &lexicalGlobalObject.vm() }; if (JSC::JSObject::getOwnPropertySlot(&thisObject, &lexicalGlobalObject, propertyName, slot)) return false; // 3. If O implements an interface that has the [OverrideBuiltins] extended attribute, then return true. if (overrideBuiltins == OverrideBuiltins::Yes) return true; // 4. Initialize prototype to be the value of the internal [[Prototype]] property of O. // 5. While prototype is not null: // 1. If prototype is not a named properties object, and prototype has an own property named P, then return false. // FIXME: Implement checking for 'named properties object'. // 2. Set prototype to be the value of the internal [[Prototype]] property of prototype. auto prototype = thisObject.getPrototypeDirect(JSC::getVM(&lexicalGlobalObject)); if (prototype.isObject() && JSC::asObject(prototype)->getPropertySlot(&lexicalGlobalObject, propertyName, slot)) return false; // 6. Return true. return true; } // An implementation of the 'named property visibility algorithm' augmented to replace the // 'supported property name' check with direct access to the implementation value returned // for the property name, via passed in functor. This allows us to avoid two looking up the // the property name twice; once for 'named property visibility algorithm' check, and then // again when the value is needed. template<OverrideBuiltins overrideBuiltins, class JSClass, class Functor> static auto accessVisibleNamedProperty(JSC::JSGlobalObject& lexicalGlobalObject, JSClass& thisObject, JSC::PropertyName propertyName, Functor&& itemAccessor) -> decltype(itemAccessor(thisObject, propertyName)) { // NOTE: While it is not specified, a Symbol can never be a 'supported property // name' so we check that first. if (propertyName.isSymbol()) return WTF::nullopt; // 1. If P is not a supported property name of O, then return false. auto result = itemAccessor(thisObject, propertyName); if (!result) return WTF::nullopt; // 2. If O has an own property named P, then return false. JSC::PropertySlot slot { &thisObject, JSC::PropertySlot::InternalMethodType::VMInquiry, &lexicalGlobalObject.vm() }; if (JSC::JSObject::getOwnPropertySlot(&thisObject, &lexicalGlobalObject, propertyName, slot)) return WTF::nullopt; // 3. If O implements an interface that has the [OverrideBuiltins] extended attribute, then return true. if (overrideBuiltins == OverrideBuiltins::Yes && !worldForDOMObject(thisObject).shouldDisableOverrideBuiltinsBehavior()) return result; // 4. Initialize prototype to be the value of the internal [[Prototype]] property of O. // 5. While prototype is not null: // 1. If prototype is not a named properties object, and prototype has an own property named P, then return false. // FIXME: Implement checking for 'named properties object'. // 2. Set prototype to be the value of the internal [[Prototype]] property of prototype. auto prototype = thisObject.getPrototypeDirect(JSC::getVM(&lexicalGlobalObject)); if (prototype.isObject() && JSC::asObject(prototype)->getPropertySlot(&lexicalGlobalObject, propertyName, slot)) return WTF::nullopt; // 6. Return true. return result; } }