Make QMetaTypeInterface POD.

QMetaTypeInterface has to be POD because it is constructed in a static
array. Constructors in POD types are not allowed so we will use a macro
instead.

Change-Id: Iab9ae776dfe4dcd7148558f02d6181c5917aa5c3
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/kernel/qmetatype.cpp

@@ -297,6 +297,14 @@ public:
     int alias;
 };
 
+namespace
+{
+union CheckThatItIsPod
+{   // This should break if QMetaTypeInterface is not a POD type
+    QMetaTypeInterface iface;
+};
+}
+
 Q_DECLARE_TYPEINFO(QCustomTypeInfo, Q_MOVABLE_TYPE);
 Q_GLOBAL_STATIC(QVector<QCustomTypeInfo>, customTypes)
 Q_GLOBAL_STATIC(QReadWriteLock, customTypesLock)
@@ -454,6 +462,10 @@ int QMetaType::registerType(const char *typeName, Deleter deleter,
             inf.typeName = normalizedTypeName;
             inf.creator = creator;
             inf.deleter = deleter;
+#ifndef QT_NO_DATASTREAM
+            inf.loadOp = 0;
+            inf.saveOp = 0;
+#endif
             inf.alias = -1;
             inf.constructor = constructor;
             inf.destructor = destructor;

src/corelib/kernel/qmetatype_p.h

@@ -113,7 +113,7 @@ QT_FOR_EACH_STATIC_WIDGETS_CLASS(QT_DECLARE_WIDGETS_MODULE_TYPES_ITER)
 
 class QMetaTypeInterface
 {
-private:
+public:
     template<typename T>
     struct Impl {
         static void *creator(const T *t)
@@ -140,31 +140,6 @@ private:
             return new (where) T;
         }
     };
-public:
-    template<typename T>
-    explicit QMetaTypeInterface(T *)
-        : creator(reinterpret_cast<QMetaType::Creator>(Impl<T>::creator))
-              , deleter(reinterpret_cast<QMetaType::Deleter>(Impl<T>::deleter))
-          #ifndef QT_NO_DATASTREAM
-              , saveOp(reinterpret_cast<QMetaType::SaveOperator>(Impl<T>::saver))
-              , loadOp(reinterpret_cast<QMetaType::LoadOperator>(Impl<T>::loader))
-          #endif
-              , constructor(reinterpret_cast<QMetaType::Constructor>(Impl<T>::constructor))
-              , destructor(reinterpret_cast<QMetaType::Destructor>(Impl<T>::destructor))
-              , size(sizeof(T))
-    {}
-
-    QMetaTypeInterface()
-        : creator(0)
-        , deleter(0)
-    #ifndef QT_NO_DATASTREAM
-        , saveOp(0)
-        , loadOp(0)
-    #endif
-        , constructor(0)
-        , destructor(0)
-        , size(0)
-    {}
 
     QMetaType::Creator creator;
     QMetaType::Deleter deleter;
@@ -177,6 +152,24 @@ public:
     int size;
 };
 
+#ifndef QT_NO_DATASTREAM
+#  define QT_METATYPE_INTERFACE_INIT_DATASTREAM_IMPL(Type) \
+    /*saveOp*/(reinterpret_cast<QMetaType::SaveOperator>(QMetaTypeInterface::Impl<Type>::saver)), \
+    /*loadOp*/(reinterpret_cast<QMetaType::LoadOperator>(QMetaTypeInterface::Impl<Type>::loader)),
+#else
+#  define QT_METATYPE_INTERFACE_INIT_DATASTREAM_IMPL(Type)
+#endif
+
+#define QT_METATYPE_INTERFACE_INIT(Type) \
+{ \
+    /*creator*/(reinterpret_cast<QMetaType::Creator>(QMetaTypeInterface::Impl<Type>::creator)), \
+    /*deleter*/(reinterpret_cast<QMetaType::Deleter>(QMetaTypeInterface::Impl<Type>::deleter)), \
+    QT_METATYPE_INTERFACE_INIT_DATASTREAM_IMPL(Type) \
+    /*constructor*/(reinterpret_cast<QMetaType::Constructor>(QMetaTypeInterface::Impl<Type>::constructor)), \
+    /*destructor*/(reinterpret_cast<QMetaType::Destructor>(QMetaTypeInterface::Impl<Type>::destructor)), \
+    /*size*/(sizeof(Type)) \
+}
+
 QT_END_NAMESPACE
 
 #endif // QMETATYPE_P_H

src/gui/kernel/qguivariant.cpp

@@ -477,7 +477,7 @@ const QVariant::Handler qt_gui_variant_handler = {
 extern Q_CORE_EXPORT const QMetaTypeInterface *qMetaTypeGuiHelper;
 
 #define QT_IMPL_METATYPEINTERFACE_GUI_TYPES(MetaTypeName, MetaTypeId, RealName) \
-    QMetaTypeInterface(static_cast<RealName*>(0)),
+    QT_METATYPE_INTERFACE_INIT(RealName),
 
 static const QMetaTypeInterface qVariantGuiHelper[] = {
     QT_FOR_EACH_STATIC_GUI_CLASS(QT_IMPL_METATYPEINTERFACE_GUI_TYPES)

src/widgets/kernel/qwidgetsvariant.cpp

@@ -141,7 +141,7 @@ static const QVariant::Handler widgets_handler = {
 extern Q_CORE_EXPORT const QMetaTypeInterface *qMetaTypeWidgetsHelper;
 
 #define QT_IMPL_METATYPEINTERFACE_WIDGETS_TYPES(MetaTypeName, MetaTypeId, RealName) \
-    QMetaTypeInterface(static_cast<RealName*>(0)),
+    QT_METATYPE_INTERFACE_INIT(RealName),
 
 static const QMetaTypeInterface qVariantWidgetsHelper[] = {
     QT_FOR_EACH_STATIC_WIDGETS_CLASS(QT_IMPL_METATYPEINTERFACE_WIDGETS_TYPES)