qt-everywhere-src-5.14.1/qtbase/src/corelib/kernel/qobject_impl.h

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#ifndef Q_QDOC

#ifndef QOBJECT_H
#error Do not include qobject_impl.h directly
#endif

#if 0
#pragma qt_sync_skip_header_check
#pragma qt_sync_stop_processing
#endif

QT_BEGIN_NAMESPACE


namespace QtPrivate {
    /*
        Logic to statically generate the array of qMetaTypeId
        ConnectionTypes<FunctionPointer<Signal>::Arguments>::types() returns an array
        of int that is suitable for the types arguments of the connection functions.

        The array only exist of all the types are declared as a metatype
        (detected using the TypesAreDeclaredMetaType helper struct)
        If one of the type is not declared, the function return 0 and the signal
        cannot be used in queued connection.
    */
    template <typename ArgList> struct TypesAreDeclaredMetaType { enum { Value = false }; };
    template <> struct TypesAreDeclaredMetaType<List<>> { enum { Value = true }; };
    template <typename Arg, typename... Tail> struct TypesAreDeclaredMetaType<List<Arg, Tail...> >
    { enum { Value = QMetaTypeId2<Arg>::Defined && TypesAreDeclaredMetaType<List<Tail...>>::Value }; };

    template <typename ArgList, bool Declared = TypesAreDeclaredMetaType<ArgList>::Value > struct ConnectionTypes
    { static const int *types() { return nullptr; } };
    template <> struct ConnectionTypes<List<>, true>
    { static const int *types() { return nullptr; } };
    template <typename... Args> struct ConnectionTypes<List<Args...>, true>
    { static const int *types() { static const int t[sizeof...(Args) + 1] = { (QtPrivate::QMetaTypeIdHelper<Args>::qt_metatype_id())..., 0 }; return t; } };

    // implementation of QSlotObjectBase for which the slot is a static function
    // Args and R are the List of arguments and the returntype of the signal to which the slot is connected.
    template<typename Func, typename Args, typename R> class QStaticSlotObject : public QSlotObjectBase
    {
        typedef QtPrivate::FunctionPointer<Func> FuncType;
        Func function;
        static void impl(int which, QSlotObjectBase *this_, QObject *r, void **a, bool *ret)
        {
            switch (which) {
            case Destroy:
                delete static_cast<QStaticSlotObject*>(this_);
                break;
            case Call:
                FuncType::template call<Args, R>(static_cast<QStaticSlotObject*>(this_)->function, r, a);
                break;
            case Compare:   // not implemented
            case NumOperations:
                Q_UNUSED(ret);
            }
        }
    public:
        explicit QStaticSlotObject(Func f) : QSlotObjectBase(&impl), function(f) {}
    };
}


QT_END_NAMESPACE

#endif