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/*
* Copyright (C) 2018-2019 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. ``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
* 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 "JSCell.h"
namespace JSC {
template<typename To, typename From>
inline To jsCast(From* from)
{
static_assert(std::is_base_of<JSCell, typename std::remove_pointer<To>::type>::value && std::is_base_of<JSCell, typename std::remove_pointer<From>::type>::value, "JS casting expects that the types you are casting to/from are subclasses of JSCell");
#if (ASSERT_ENABLED || ENABLE(SECURITY_ASSERTIONS)) && CPU(X86_64)
if (from && !from->JSCell::inherits(from->JSCell::vm(), std::remove_pointer<To>::type::info()))
reportZappedCellAndCrash(*from->JSCell::heap(), from);
#else
ASSERT_WITH_SECURITY_IMPLICATION(!from || from->JSCell::inherits(from->JSCell::vm(), std::remove_pointer<To>::type::info()));
#endif
return static_cast<To>(from);
}
template<typename To>
inline To jsCast(JSValue from)
{
static_assert(std::is_base_of<JSCell, typename std::remove_pointer<To>::type>::value, "JS casting expects that the types you are casting to is a subclass of JSCell");
#if (ASSERT_ENABLED || ENABLE(SECURITY_ASSERTIONS)) && CPU(X86_64)
ASSERT_WITH_SECURITY_IMPLICATION(from.isCell());
JSCell* cell = from.asCell();
if (!cell->JSCell::inherits(cell->vm(), std::remove_pointer<To>::type::info()))
reportZappedCellAndCrash(*cell->JSCell::heap(), cell);
#else
ASSERT_WITH_SECURITY_IMPLICATION(from.isCell() && from.asCell()->JSCell::inherits(from.asCell()->vm(), std::remove_pointer<To>::type::info()));
#endif
return static_cast<To>(from.asCell());
}
// The first and last JSType are inclusive
struct JSTypeRange {
bool contains(JSType type) const { return first <= type && type <= last; }
JSType first;
JSType last;
};
// Specific type overloads.
#define FOR_EACH_JS_DYNAMIC_CAST_JS_TYPE_OVERLOAD(macro) \
macro(JSImmutableButterfly, JSType::JSImmutableButterflyType, JSType::JSImmutableButterflyType) \
macro(JSStringIterator, JSType::JSStringIteratorType, JSType::JSStringIteratorType) \
macro(JSObject, FirstObjectType, LastObjectType) \
macro(JSFinalObject, JSType::FinalObjectType, JSType::FinalObjectType) \
macro(JSFunction, JSType::JSFunctionType, JSType::JSFunctionType) \
macro(InternalFunction, JSType::InternalFunctionType, JSType::NullSetterFunctionType) \
macro(NullSetterFunction, JSType::NullSetterFunctionType, JSType::NullSetterFunctionType) \
macro(JSArray, JSType::ArrayType, JSType::DerivedArrayType) \
macro(JSArrayIterator, JSType::JSArrayIteratorType, JSType::JSArrayIteratorType) \
macro(JSArrayBuffer, JSType::ArrayBufferType, JSType::ArrayBufferType) \
macro(JSArrayBufferView, FirstTypedArrayType, LastTypedArrayType) \
macro(JSPromise, JSType::JSPromiseType, JSType::JSPromiseType) \
macro(JSProxy, JSType::PureForwardingProxyType, JSType::PureForwardingProxyType) \
macro(JSSet, JSType::JSSetType, JSType::JSSetType) \
macro(JSMap, JSType::JSMapType, JSType::JSMapType) \
macro(JSWeakSet, JSType::JSWeakSetType, JSType::JSWeakSetType) \
macro(JSWeakMap, JSType::JSWeakMapType, JSType::JSWeakMapType) \
macro(NumberObject, JSType::NumberObjectType, JSType::NumberObjectType) \
macro(ProxyObject, JSType::ProxyObjectType, JSType::ProxyObjectType) \
macro(RegExpObject, JSType::RegExpObjectType, JSType::RegExpObjectType) \
macro(JSWebAssemblyModule, JSType::WebAssemblyModuleType, JSType::WebAssemblyModuleType) \
macro(DirectArguments, JSType::DirectArgumentsType, JSType::DirectArgumentsType) \
macro(ScopedArguments, JSType::ScopedArgumentsType, JSType::ScopedArgumentsType) \
macro(ClonedArguments, JSType::ClonedArgumentsType, JSType::ClonedArgumentsType) \
macro(JSGlobalObject, JSType::GlobalObjectType, JSType::GlobalObjectType) \
macro(JSGlobalLexicalEnvironment, JSType::GlobalLexicalEnvironmentType, JSType::GlobalLexicalEnvironmentType) \
macro(JSSegmentedVariableObject, JSType::GlobalObjectType, JSType::GlobalLexicalEnvironmentType) \
macro(JSModuleEnvironment, JSType::ModuleEnvironmentType, JSType::ModuleEnvironmentType) \
macro(JSLexicalEnvironment, JSType::LexicalEnvironmentType, JSType::ModuleEnvironmentType) \
macro(JSSymbolTableObject, JSType::GlobalObjectType, JSType::ModuleEnvironmentType) \
macro(JSScope, JSType::GlobalObjectType, JSType::WithScopeType) \
macro(StringObject, JSType::StringObjectType, JSType::DerivedStringObjectType) \
// Forward declare the classes because they may not already exist.
#define FORWARD_DECLARE_OVERLOAD_CLASS(className, jsType, op) class className;
FOR_EACH_JS_DYNAMIC_CAST_JS_TYPE_OVERLOAD(FORWARD_DECLARE_OVERLOAD_CLASS)
#undef FORWARD_DECLARE_OVERLOAD_CLASS
namespace JSCastingHelpers {
template<bool isFinal>
struct FinalTypeDispatcher {
template<typename Target, typename From>
static inline bool inheritsGeneric(VM& vm, From* from)
{
static_assert(!std::is_same<JSObject*, Target*>::value, "This ensures our overloads work");
static_assert(std::is_base_of<JSCell, Target>::value && std::is_base_of<JSCell, typename std::remove_pointer<From>::type>::value, "JS casting expects that the types you are casting to/from are subclasses of JSCell");
// Do not use inherits<Target>(vm) since inherits<T> depends on this function.
return from->JSCell::inherits(vm, Target::info());
}
};
template<>
struct FinalTypeDispatcher</* isFinal */ true> {
template<typename Target, typename From>
static inline bool inheritsGeneric(VM& vm, From* from)
{
static_assert(!std::is_same<JSObject*, Target*>::value, "This ensures our overloads work");
static_assert(std::is_base_of<JSCell, Target>::value && std::is_base_of<JSCell, typename std::remove_pointer<From>::type>::value, "JS casting expects that the types you are casting to/from are subclasses of JSCell");
static_assert(std::is_final<Target>::value, "Target is a final type");
bool canCast = from->JSCell::classInfo(vm) == Target::info();
// Do not use inherits<Target>(vm) since inherits<T> depends on this function.
ASSERT_UNUSED(vm, canCast == from->JSCell::inherits(vm, Target::info()));
return canCast;
}
};
template<typename Target, typename From>
inline bool inheritsJSTypeImpl(VM& vm, From* from, JSTypeRange range)
{
static_assert(std::is_base_of<JSCell, Target>::value && std::is_base_of<JSCell, typename std::remove_pointer<From>::type>::value, "JS casting expects that the types you are casting to/from are subclasses of JSCell");
bool canCast = range.contains(from->type());
// Do not use inherits<Target>(vm) since inherits<T> depends on this function.
ASSERT_UNUSED(vm, canCast == from->JSCell::inherits(vm, Target::info()));
return canCast;
}
// C++ has bad syntax so we need to use this struct because C++ doesn't have a
// way to say that we are overloading just the first type in a template list...
template<typename Target>
struct InheritsTraits {
static constexpr std::optional<JSTypeRange> typeRange { std::nullopt };
template<typename From>
static inline bool inherits(VM& vm, From* from) { return FinalTypeDispatcher<std::is_final<Target>::value>::template inheritsGeneric<Target>(vm, from); }
};
#define DEFINE_TRAITS_FOR_JS_TYPE_OVERLOAD(className, firstJSType, lastJSType) \
template<> \
struct InheritsTraits<className> { \
static constexpr std::optional<JSTypeRange> typeRange { { static_cast<JSType>(firstJSType), static_cast<JSType>(lastJSType) } }; \
template<typename From> \
static inline bool inherits(VM& vm, From* from) { return inheritsJSTypeImpl<className, From>(vm, from, *typeRange); } \
}; \
FOR_EACH_JS_DYNAMIC_CAST_JS_TYPE_OVERLOAD(DEFINE_TRAITS_FOR_JS_TYPE_OVERLOAD)
#undef DEFINE_TRAITS_FOR_JS_TYPE_OVERLOAD
template<typename Target, typename From>
bool inherits(VM& vm, From* from)
{
using Dispatcher = InheritsTraits<Target>;
return Dispatcher::template inherits(vm, from);
}
} // namespace JSCastingHelpers
template<typename To, typename From>
To jsDynamicCast(VM& vm, From* from)
{
using Dispatcher = JSCastingHelpers::InheritsTraits<typename std::remove_cv<typename std::remove_pointer<To>::type>::type>;
if (LIKELY(Dispatcher::template inherits(vm, from)))
return static_cast<To>(from);
return nullptr;
}
template<typename To>
To jsDynamicCast(VM& vm, JSValue from)
{
if (UNLIKELY(!from.isCell()))
return nullptr;
return jsDynamicCast<To>(vm, from.asCell());
}
template<typename To, typename From>
To jsSecureCast(VM& vm, From from)
{
auto* result = jsDynamicCast<To>(vm, from);
RELEASE_ASSERT_WITH_SECURITY_IMPLICATION(result);
return result;
}
}
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