qmetatype_p.h

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// Copyright (C) 2016 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
 
#ifndef QMETATYPE_P_H
#define QMETATYPE_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 <QtCore/private/qglobal_p.h>
#include "qmetatype.h"
 
QT_BEGIN_NAMESPACE
 
#define QMETATYPE_CONVERTER(To, From, assign_and_return) \
    case makePair(QMetaType::To, QMetaType::From): \
        if (onlyCheck) \
            return true; \
        { \
            const From &source = *static_cast<const From *>(from); \
            To &result = *static_cast<To *>(to); \
            assign_and_return \
        }
#define QMETATYPE_CONVERTER_ASSIGN(To, From) \
    QMETATYPE_CONVERTER(To, From, result = To(source); return true;)
 
#define QMETATYPE_CONVERTER_FUNCTION(To, assign_and_return) \
        { \
            To &result = *static_cast<To *>(r); \
            assign_and_return \
        }
 
class Q_CORE_EXPORT QMetaTypeModuleHelper
{
    Q_DISABLE_COPY_MOVE(QMetaTypeModuleHelper)
protected:
    QMetaTypeModuleHelper() = default;
    ~QMetaTypeModuleHelper() = default;
public:
    Q_WEAK_OVERLOAD // prevent it from entering the ABI and rendering constexpr useless
    static constexpr auto makePair(int from, int to) -> quint64
    {
        return (quint64(from) << 32) + quint64(to);
    }
 
    virtual const QtPrivate::QMetaTypeInterface *interfaceForType(int) const = 0;
    virtual bool convert(const void *, int, void *, int) const;
};
 
extern Q_CORE_EXPORT const QMetaTypeModuleHelper *qMetaTypeGuiHelper;
extern Q_CORE_EXPORT const QMetaTypeModuleHelper *qMetaTypeWidgetsHelper;
 
namespace QtMetaTypePrivate {
template<typename T>
struct TypeDefinition
{
    static const bool IsAvailable = true;
};
 
// Ignore these types, as incomplete
#ifdef QT_BOOTSTRAPPED
template<> struct TypeDefinition<QBitArray> { static const bool IsAvailable = false; };
template<> struct TypeDefinition<QCborArray> { static const bool IsAvailable = false; };
template<> struct TypeDefinition<QCborMap> { static const bool IsAvailable = false; };
template<> struct TypeDefinition<QCborSimpleType> { static const bool IsAvailable = false; };
template<> struct TypeDefinition<QCborValue> { static const bool IsAvailable = false; };
#if QT_CONFIG(easingcurve)
template<> struct TypeDefinition<QEasingCurve> { static const bool IsAvailable = false; };
#endif
template<> struct TypeDefinition<QJsonArray> { static const bool IsAvailable = false; };
template<> struct TypeDefinition<QJsonDocument> { static const bool IsAvailable = false; };
template<> struct TypeDefinition<QJsonObject> { static const bool IsAvailable = false; };
template<> struct TypeDefinition<QJsonValue> { static const bool IsAvailable = false; };
template<> struct TypeDefinition<QUrl> { static const bool IsAvailable = false; };
template<> struct TypeDefinition<QByteArrayList> { static const bool IsAvailable = false; };
#endif
#ifdef QT_NO_GEOM_VARIANT
template<> struct TypeDefinition<QRect> { static const bool IsAvailable = false; };
template<> struct TypeDefinition<QRectF> { static const bool IsAvailable = false; };
template<> struct TypeDefinition<QSize> { static const bool IsAvailable = false; };
template<> struct TypeDefinition<QSizeF> { static const bool IsAvailable = false; };
template<> struct TypeDefinition<QLine> { static const bool IsAvailable = false; };
template<> struct TypeDefinition<QLineF> { static const bool IsAvailable = false; };
template<> struct TypeDefinition<QPoint> { static const bool IsAvailable = false; };
template<> struct TypeDefinition<QPointF> { static const bool IsAvailable = false; };
#endif
#if !QT_CONFIG(regularexpression)
template<> struct TypeDefinition<QRegularExpression> { static const bool IsAvailable = false; };
#endif
#ifdef QT_NO_CURSOR
template<> struct TypeDefinition<QCursor> { static const bool IsAvailable = false; };
#endif
#ifdef QT_NO_MATRIX4X4
template<> struct TypeDefinition<QMatrix4x4> { static const bool IsAvailable = false; };
#endif
#ifdef QT_NO_VECTOR2D
template<> struct TypeDefinition<QVector2D> { static const bool IsAvailable = false; };
#endif
#ifdef QT_NO_VECTOR3D
template<> struct TypeDefinition<QVector3D> { static const bool IsAvailable = false; };
#endif
#ifdef QT_NO_VECTOR4D
template<> struct TypeDefinition<QVector4D> { static const bool IsAvailable = false; };
#endif
#ifdef QT_NO_QUATERNION
template<> struct TypeDefinition<QQuaternion> { static const bool IsAvailable = false; };
#endif
#ifdef QT_NO_ICON
template<> struct TypeDefinition<QIcon> { static const bool IsAvailable = false; };
#endif
 
template <typename T> inline bool isInterfaceFor(const QtPrivate::QMetaTypeInterface *iface)
{
    // typeId for built-in types are fixed and require no registration
    static_assert(QMetaTypeId2<T>::IsBuiltIn, "This function only works for built-in types");
    static constexpr int typeId = QtPrivate::BuiltinMetaType<T>::value;
    return iface->typeId.loadRelaxed() == typeId;
}
 
template <typename FPointer>
inline bool checkMetaTypeFlagOrPointer(const QtPrivate::QMetaTypeInterface *iface, FPointer ptr, QMetaType::TypeFlag Flag)
{
    // helper to the isXxxConstructible & isDestructible functions below: a
    // meta type has the trait if the trait is trivial or we have the pointer
    // to perform the operation
    Q_ASSERT(!isInterfaceFor<void>(iface));
    Q_ASSERT(iface->size);
    return ptr != nullptr || (iface->flags & Flag) == 0;
}
 
inline bool isDefaultConstructible(const QtPrivate::QMetaTypeInterface *iface) noexcept
{
    return checkMetaTypeFlagOrPointer(iface, iface->defaultCtr, QMetaType::NeedsConstruction);
}
 
inline bool isCopyConstructible(const QtPrivate::QMetaTypeInterface *iface) noexcept
{
    return checkMetaTypeFlagOrPointer(iface, iface->copyCtr, QMetaType::NeedsCopyConstruction);
}
 
inline bool isMoveConstructible(const QtPrivate::QMetaTypeInterface *iface) noexcept
{
    return checkMetaTypeFlagOrPointer(iface, iface->moveCtr, QMetaType::NeedsMoveConstruction);
}
 
inline bool isDestructible(const QtPrivate::QMetaTypeInterface *iface) noexcept
{
    /* For metatypes of revision 1, the NeedsDestruction was set even for trivially
       destructible types, but their dtor pointer would be null.
       For that reason, we need the additional check here.
     */
    return iface->revision < 1 ||
           checkMetaTypeFlagOrPointer(iface, iface->dtor, QMetaType::NeedsDestruction);
}
 
inline void defaultConstruct(const QtPrivate::QMetaTypeInterface *iface, void *where)
{
    Q_ASSERT(isDefaultConstructible(iface));
    if (iface->defaultCtr)
        iface->defaultCtr(iface, where);
    else
        memset(where, 0, iface->size);
}
 
inline void copyConstruct(const QtPrivate::QMetaTypeInterface *iface, void *where, const void *copy)
{
    Q_ASSERT(isCopyConstructible(iface));
    if (iface->copyCtr)
        iface->copyCtr(iface, where, copy);
    else
        memcpy(where, copy, iface->size);
}
 
inline void moveConstruct(const QtPrivate::QMetaTypeInterface *iface, void *where, void *copy)
{
    Q_ASSERT(isMoveConstructible(iface));
    if (iface->moveCtr)
        iface->moveCtr(iface, where, copy);
    else
        memcpy(where, copy, iface->size);
}
 
inline void construct(const QtPrivate::QMetaTypeInterface *iface, void *where, const void *copy)
{
    if (copy)
        copyConstruct(iface, where, copy);
    else
        defaultConstruct(iface, where);
}
 
inline void destruct(const QtPrivate::QMetaTypeInterface *iface, void *where)
{
    Q_ASSERT(isDestructible(iface));
    if (iface->dtor)
        iface->dtor(iface, where);
}
 
const char *typedefNameForType(const QtPrivate::QMetaTypeInterface *type_d);
 
template<typename T>
static const QT_PREPEND_NAMESPACE(QtPrivate::QMetaTypeInterface) *getInterfaceFromType()
{
    if constexpr (QtMetaTypePrivate::TypeDefinition<T>::IsAvailable) {
        return &QT_PREPEND_NAMESPACE(QtPrivate::QMetaTypeInterfaceWrapper)<T>::metaType;
    }
    return nullptr;
}
 
#define QT_METATYPE_CONVERT_ID_TO_TYPE(MetaTypeName, MetaTypeId, RealName)                         \
    case QMetaType::MetaTypeName:                                                                  \
        return QtMetaTypePrivate::getInterfaceFromType<RealName>();
 
} //namespace QtMetaTypePrivate
 
QT_END_NAMESPACE
 
#endif // QMETATYPE_P_H