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/*
* 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"
#include "JSDOMExceptionHandling.h"
namespace WebCore {
// Implementations of the abstract operations defined at
// https://webidl.spec.whatwg.org/#legacy-platform-object-abstract-ops
enum class LegacyOverrideBuiltIns : bool { No, Yes };
// An implementation of the 'named property visibility algorithm'
// https://webidl.spec.whatwg.org/#dfn-named-property-visibility
template<LegacyOverrideBuiltIns 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 [LegacyOverrideBuiltIns] extended attribute, then return true.
if (overrideBuiltins == LegacyOverrideBuiltIns::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();
if (prototype.isObject() && JSC::asObject(prototype)->getPropertySlot(&lexicalGlobalObject, propertyName, slot))
return false;
// 6. Return true.
return true;
}
// NOTE: Named getters are little odd. To avoid doing duplicate lookups (once when checking if
// the property name is a 'supported property name' and once to get the value) we signal
// that a property is supported by whether or not it is 'null' (where what null means is
// dependant on the IDL type). This is based on the assumption that no named getter will
// ever actually want to return null as an actual return value, which seems like an ok
// assumption to make (should it turn out this doesn't hold in the future, we have lots
// of options; do two lookups, add an extra layer of Optional, etc.).
template<typename IDLType, typename JSClass, typename InnerItemAccessor>
static decltype(auto) visibleNamedPropertyItemAccessorFunctor(InnerItemAccessor&& innerItemAccessor)
{
if constexpr (IsExceptionOr<std::invoke_result_t<InnerItemAccessor, JSClass&, JSC::PropertyName>>) {
using ReturnType = ExceptionOr<typename IDLType::ImplementationType>;
return [innerItemAccessor = std::forward<InnerItemAccessor>(innerItemAccessor)] (JSClass& thisObject, JSC::PropertyName propertyName) -> std::optional<ReturnType> {
auto result = innerItemAccessor(thisObject, propertyName);
if (result.hasException())
return ReturnType { result.releaseException() };
if (!IDLType::isNullValue(result.returnValue()))
return ReturnType { IDLType::extractValueFromNullable(result.releaseReturnValue()) };
return std::nullopt;
};
} else {
using ReturnType = typename IDLType::ImplementationType;
return [innerItemAccessor = std::forward<InnerItemAccessor>(innerItemAccessor)] (JSClass& thisObject, JSC::PropertyName propertyName) -> std::optional<ReturnType> {
auto result = innerItemAccessor(thisObject, propertyName);
if (!IDLType::isNullValue(result))
return ReturnType { IDLType::extractValueFromNullable(result) };
return std::nullopt;
};
}
}
// 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<LegacyOverrideBuiltIns overrideBuiltins, class JSClass, class ItemAccessor>
static auto accessVisibleNamedProperty(JSC::JSGlobalObject& lexicalGlobalObject, JSClass& thisObject, JSC::PropertyName propertyName, ItemAccessor&& 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 std::nullopt;
// 1. If P is not a supported property name of O, then return false.
auto result = itemAccessor(thisObject, propertyName);
if (!result)
return std::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 std::nullopt;
// 3. If O implements an interface that has the [LegacyOverrideBuiltIns] extended attribute, then return true.
if (overrideBuiltins == LegacyOverrideBuiltIns::Yes && !worldForDOMObject(thisObject).shouldDisableLegacyOverrideBuiltInsBehavior())
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();
if (prototype.isObject() && JSC::asObject(prototype)->getPropertySlot(&lexicalGlobalObject, propertyName, slot))
return std::nullopt;
// 6. Return true.
return result;
}
// This implements steps 2.2 through 2.5 of https://webidl.spec.whatwg.org/#legacy-platform-object-delete.
template<typename Functor> bool performLegacyPlatformObjectDeleteOperation(JSC::JSGlobalObject& lexicalGlobalObject, Functor&& functor)
{
using ReturnType = std::invoke_result_t<Functor>;
if constexpr (IsExceptionOr<ReturnType>) {
auto result = functor();
if (result.hasException()) {
auto throwScope = DECLARE_THROW_SCOPE(JSC::getVM(&lexicalGlobalObject));
propagateException(lexicalGlobalObject, throwScope, result.releaseException());
return true;
}
if constexpr (std::is_same_v<ReturnType, ExceptionOr<bool>>)
return result.releaseReturnValue();
return true;
}
if constexpr (std::is_same_v<ReturnType, bool>)
return functor();
functor();
return true;
}
}
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