qv4vtable_p.h

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// Copyright (C) 2018 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
// Qt-Security score:significant
#ifndef QV4VTABLE_P_H
#define QV4VTABLE_P_H
 
//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists purely as an
// implementation detail.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//
 
#include "qv4global_p.h"
#include <QtCore/qmetaobject.h>
 
QT_BEGIN_NAMESPACE
 
class QObject;
namespace QV4 {
 
struct Lookup;
 
struct Q_QML_EXPORT OwnPropertyKeyIterator {
    virtual ~OwnPropertyKeyIterator() = 0;
    virtual PropertyKey next(const Object *o, Property *p = nullptr, PropertyAttributes *attrs = nullptr) = 0;
};
 
struct VTable
{
    typedef void (*Destroy)(Heap::Base *);
    typedef void (*MarkObjects)(Heap::Base *, MarkStack *markStack);
    typedef bool (*IsEqualTo)(Managed *m, Managed *other);
 
    typedef ReturnedValue (*Get)(const Managed *, PropertyKey id, const Value *receiver, bool *hasProperty);
    typedef bool (*Put)(Managed *, PropertyKey id, const Value &value, Value *receiver);
    typedef bool (*DeleteProperty)(Managed *m, PropertyKey id);
    typedef bool (*HasProperty)(const Managed *m, PropertyKey id);
    typedef PropertyAttributes (*GetOwnProperty)(const Managed *m, PropertyKey id, Property *p);
    typedef bool (*DefineOwnProperty)(Managed *m, PropertyKey id, const Property *p, PropertyAttributes attrs);
    typedef bool (*IsExtensible)(const Managed *);
    typedef bool (*PreventExtensions)(Managed *);
    typedef Heap::Object *(*GetPrototypeOf)(const Managed *);
    typedef bool (*SetPrototypeOf)(Managed *, const Object *);
    typedef qint64 (*GetLength)(const Managed *m);
    typedef OwnPropertyKeyIterator *(*OwnPropertyKeys)(const Object *m, Value *target);
    typedef ReturnedValue (*InstanceOf)(const Object *typeObject, const Value &var);
 
    typedef ReturnedValue (*Call)(const FunctionObject *, const Value *thisObject, const Value *argv, int argc);
    typedef void (*CallWithMetaTypes)(const FunctionObject *, QObject *, void **, const QMetaType *, int);
    typedef ReturnedValue (*CallAsConstructor)(const FunctionObject *, const Value *argv, int argc, const Value *newTarget);
 
    typedef ReturnedValue (*ResolveLookupGetter)(const Object *, ExecutionEngine *, Lookup *);
    typedef bool (*ResolveLookupSetter)(Object *, ExecutionEngine *, Lookup *, const Value &);
 
    typedef int (*Metacall)(Object *, QMetaObject::Call, int, void **);
 
    const VTable * const parent;
    quint16 inlinePropertyOffset;
    quint16 nInlineProperties;
    quint8 isExecutionContext;
    quint8 isString;
    quint8 isObject;
    quint8 isTailCallable;
    quint8 isErrorObject;
    quint8 isArrayData;
    quint8 isStringOrSymbol;
    quint8 type;
    quint8 unused[4];
    const char *className;
 
    Destroy destroy;
    MarkObjects markObjects;
    IsEqualTo isEqualTo;
 
    Get get;
    Put put;
    DeleteProperty deleteProperty;
    HasProperty hasProperty;
    GetOwnProperty getOwnProperty;
    DefineOwnProperty defineOwnProperty;
    IsExtensible isExtensible;
    PreventExtensions preventExtensions;
    GetPrototypeOf getPrototypeOf;
    SetPrototypeOf setPrototypeOf;
    GetLength getLength;
    OwnPropertyKeys ownPropertyKeys;
    InstanceOf instanceOf;
 
    Call call;
    CallAsConstructor callAsConstructor;
    CallWithMetaTypes callWithMetaTypes;
 
    ResolveLookupGetter resolveLookupGetter;
    ResolveLookupSetter resolveLookupSetter;
 
    Metacall metacall;
};
 
template<VTable::CallWithMetaTypes call>
struct VTableCallWithMetaTypesWrapper { constexpr static VTable::CallWithMetaTypes c = call; };
 
template<VTable::Call call>
struct VTableCallWrapper { constexpr static VTable::Call c = call; };
 
template<class Class>
constexpr VTable::CallWithMetaTypes vtableMetaTypesCallEntry()
{
    // If Class overrides virtualCallWithMetaTypes, return that.
    // Otherwise, if it overrides virtualCall, return convertAndCall.
    // Otherwise, just return whatever the base class had.
 
    // A simple == on methods is not considered constexpr, so we have to jump through some hoops.
 
    static_assert(
            std::is_same_v<
                    VTableCallWithMetaTypesWrapper<Class::virtualCallWithMetaTypes>,
                    VTableCallWithMetaTypesWrapper<Class::SuperClass::virtualCallWithMetaTypes>>
                || !std::is_same_v<
                    VTableCallWithMetaTypesWrapper<Class::virtualCallWithMetaTypes>,
                    VTableCallWithMetaTypesWrapper<nullptr>>,
            "You mustn't override virtualCallWithMetaTypes with nullptr");
 
    static_assert(
            std::is_same_v<
                    VTableCallWithMetaTypesWrapper<Class::virtualConvertAndCall>,
                    VTableCallWithMetaTypesWrapper<Class::SuperClass::virtualConvertAndCall>>
                || !std::is_same_v<
                    VTableCallWithMetaTypesWrapper<Class::virtualConvertAndCall>,
                    VTableCallWithMetaTypesWrapper<nullptr>>,
            "You mustn't override virtualConvertAndCall with nullptr");
 
    if constexpr (
            std::is_same_v<
                    VTableCallWithMetaTypesWrapper<Class::virtualCallWithMetaTypes>,
                    VTableCallWithMetaTypesWrapper<Class::SuperClass::virtualCallWithMetaTypes>>
            && !std::is_same_v<
                    VTableCallWrapper<Class::virtualCall>,
                    VTableCallWrapper<Class::SuperClass::virtualCall>>) {
        // Converting from metatypes to JS signature is easy.
        return Class::virtualConvertAndCall;
    }
 
    return Class::virtualCallWithMetaTypes;
}
 
template<class Class>
constexpr VTable::Call vtableJsTypesCallEntry()
{
    // If Class overrides virtualCall, return that.
    // Otherwise, if it overrides virtualCallWithMetaTypes, fail.
    // (We cannot determine the target types to call virtualCallWithMetaTypes in that case)
    // Otherwise, just return whatever the base class had.
 
    // A simple == on methods is not considered constexpr, so we have to jump through some hoops.
 
    static_assert(
            !std::is_same_v<
                    VTableCallWrapper<Class::virtualCall>,
                    VTableCallWrapper<Class::SuperClass::virtualCall>>
                || std::is_same_v<
                    VTableCallWithMetaTypesWrapper<Class::virtualCallWithMetaTypes>,
                    VTableCallWithMetaTypesWrapper<Class::SuperClass::virtualCallWithMetaTypes>>,
            "If you override virtualCallWithMetaTypes, override virtualCall, too");
 
    static_assert(
            std::is_same_v<
                    VTableCallWrapper<Class::virtualCall>,
                    VTableCallWrapper<Class::SuperClass::virtualCall>>
                || VTableCallWrapper<Class::virtualCall>::c != nullptr,
            "You mustn't override virtualCall with nullptr");
 
    return Class::virtualCall;
}
 
struct VTableBase {
protected:
    static constexpr VTable::Destroy virtualDestroy = nullptr;
    static constexpr VTable::IsEqualTo virtualIsEqualTo = nullptr;
 
    static constexpr VTable::Get virtualGet = nullptr;
    static constexpr VTable::Put virtualPut = nullptr;
    static constexpr VTable::DeleteProperty virtualDeleteProperty = nullptr;
    static constexpr VTable::HasProperty virtualHasProperty = nullptr;
    static constexpr VTable::GetOwnProperty virtualGetOwnProperty = nullptr;
    static constexpr VTable::DefineOwnProperty virtualDefineOwnProperty = nullptr;
    static constexpr VTable::IsExtensible virtualIsExtensible = nullptr;
    static constexpr VTable::PreventExtensions virtualPreventExtensions = nullptr;
    static constexpr VTable::GetPrototypeOf virtualGetPrototypeOf = nullptr;
    static constexpr VTable::SetPrototypeOf virtualSetPrototypeOf = nullptr;
    static constexpr VTable::GetLength virtualGetLength = nullptr;
    static constexpr VTable::OwnPropertyKeys virtualOwnPropertyKeys = nullptr;
    static constexpr VTable::InstanceOf virtualInstanceOf = nullptr;
 
    static constexpr VTable::Call virtualCall = nullptr;
    static constexpr VTable::CallAsConstructor virtualCallAsConstructor = nullptr;
    static constexpr VTable::CallWithMetaTypes virtualCallWithMetaTypes = nullptr;
    static constexpr VTable::CallWithMetaTypes virtualConvertAndCall = nullptr;
 
    static constexpr VTable::ResolveLookupGetter virtualResolveLookupGetter = nullptr;
    static constexpr VTable::ResolveLookupSetter virtualResolveLookupSetter = nullptr;
 
    static constexpr VTable::Metacall virtualMetacall = nullptr;
 
    template<class Class>
    friend constexpr VTable::CallWithMetaTypes vtableMetaTypesCallEntry();
 
    template<class Class>
    friend constexpr VTable::Call vtableJsTypesCallEntry();
};
 
#define DEFINE_MANAGED_VTABLE_INT(classname, parentVTable) \
{
    parentVTable,
    (sizeof(classname::Data) + sizeof(QV4::Value) - 1)/sizeof(QV4::Value),
    (sizeof(classname::Data) + (classname::NInlineProperties*sizeof(QV4::Value)) + QV4::Chunk::SlotSize - 1)/QV4::Chunk::SlotSize*QV4::Chunk::SlotSize/sizeof(QV4::Value)
        - (sizeof(classname::Data) + sizeof(QV4::Value) - 1)/sizeof(QV4::Value),
    classname::IsExecutionContext,
    classname::IsString,
    classname::IsObject,
    classname::IsTailCallable,
    classname::IsErrorObject,
    classname::IsArrayData,
    classname::IsStringOrSymbol,
    classname::MyType,
    { 0, 0, 0, 0 },
    #classname,
 
    classname::virtualDestroy,
    classname::Data::markObjects,
    classname::virtualIsEqualTo,
 
    classname::virtualGet,
    classname::virtualPut,
    classname::virtualDeleteProperty,
    classname::virtualHasProperty,
    classname::virtualGetOwnProperty,
    classname::virtualDefineOwnProperty,
    classname::virtualIsExtensible,
    classname::virtualPreventExtensions,
    classname::virtualGetPrototypeOf,
    classname::virtualSetPrototypeOf,
    classname::virtualGetLength,
    classname::virtualOwnPropertyKeys,
    classname::virtualInstanceOf,
 
    QV4::vtableJsTypesCallEntry<classname>(),
    classname::virtualCallAsConstructor,
    QV4::vtableMetaTypesCallEntry<classname>(),
 
    classname::virtualResolveLookupGetter,
    classname::virtualResolveLookupSetter,
    classname::virtualMetacall              \
}
 
#define DEFINE_MANAGED_VTABLE(classname) const
      QV4::VTable classname::static_vtbl = DEFINE_MANAGED_VTABLE_INT(classname, 0)
 
#define V4_OBJECT2(DataClass, superClass)
    private:
        DataClass() = delete;
        Q_DISABLE_COPY(DataClass)
    public:
        Q_MANAGED_CHECK
        typedef QV4::Heap::DataClass Data;
        typedef superClass SuperClass;
        static const QV4::VTable static_vtbl;
        static inline const QV4::VTable *staticVTable() { return &static_vtbl; }
        V4_MANAGED_SIZE_TEST
        QV4::Heap::DataClass *d() const { return static_cast<QV4::Heap::DataClass *>(m()); }
        static_assert(std::is_trivially_copyable_v<QV4::Heap::DataClass>);
        static_assert(std::is_trivially_default_constructible_v<QV4::Heap::DataClass>);
 
#define V4_PROTOTYPE(p)
    static QV4::Object *defaultPrototype(QV4::ExecutionEngine *e)
    { return e->p(); }
 
 
#define DEFINE_OBJECT_VTABLE_BASE(classname)
    const QV4::VTable classname::static_vtbl = DEFINE_MANAGED_VTABLE_INT(classname, (std::is_same<classname::SuperClass, Object>::value) ? nullptr : &classname::SuperClass::static_vtbl)
 
#define DEFINE_OBJECT_VTABLE(classname) DEFINE_OBJECT_VTABLE_BASE
                         (classname)
 
#define DEFINE_OBJECT_TEMPLATE_VTABLE(classname) template
        <> DEFINE_OBJECT_VTABLE_BASE(classname)
 
}
 
QT_END_NAMESPACE
 
#endif