diff options
author | Nils Jeisecke <nils.jeisecke@saltation.com> | 2018-03-02 16:57:11 +0100 |
---|---|---|
committer | Nils Jeisecke <nils.jeisecke@saltation.com> | 2018-03-10 06:12:24 +0000 |
commit | fee8944cbe2a976e1b4a71c5df048e84a0bc6db0 (patch) | |
tree | 210fe33464d31b577f92a078faa2fed738540788 | |
parent | b767c7363f7ceda88553fb8abb6d4cb70b70bd2f (diff) |
Allow use of template class instances inheriting from a Q_GADGET in Qml
The Q_GADGET macro cannot be used in templates. It can however be useful
to derive a template class from a Q_GADGET enabled base class to benefit
from type safety features in C++ (e.g. the class could represent an id
or handle for some C++ type).
For proper wrapping of a QVariant with a gadget value in a QJSValue, the
QMetaType::IsGadget flag must be set for the registered template
instance type - which does not happen prior to the fix because
IsGadgetHelper requires qt_check_for_QGADGET_macro to be defined in the
registered class but not in an ancestor class - in other words: The
class must declare Q_GADGET.
To overcome this, IsGadgetHelper/IsPointerToGadgetHelper can now
differentiate between a Q_GADGET flagged class (allowing
automatic registration) and a derived class, e.g. a template class
(forcing Q_DECLARE_METATYPE to be used explicitly).
[ChangeLog][QtCore][QMetaObject] It is now possible to use template
class instances inheriting from a Q_GADGET in Qml
Task-number: QTBUG-66744
Change-Id: I7632ad45cff79fa422b3f852ca0b963f35fab155
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>
-rw-r--r-- | src/corelib/kernel/qmetatype.h | 26 | ||||
-rw-r--r-- | tests/auto/corelib/kernel/qmetatype/tst_qmetatype.cpp | 19 |
2 files changed, 35 insertions, 10 deletions
diff --git a/src/corelib/kernel/qmetatype.h b/src/corelib/kernel/qmetatype.h index 455d0350e0..4674efe568 100644 --- a/src/corelib/kernel/qmetatype.h +++ b/src/corelib/kernel/qmetatype.h @@ -1381,7 +1381,7 @@ namespace QtPrivate }; template<typename T, typename Enable = void> - struct IsGadgetHelper { enum { Value = false }; }; + struct IsGadgetHelper { enum { IsRealGadget = false, IsGadgetOrDerivedFrom = false }; }; template<typename T> struct IsGadgetHelper<T, typename T::QtGadgetHelper> @@ -1389,11 +1389,14 @@ namespace QtPrivate template <typename X> static char checkType(void (X::*)()); static void *checkType(void (T::*)()); - enum { Value = sizeof(checkType(&T::qt_check_for_QGADGET_macro)) == sizeof(void *) }; + enum { + IsRealGadget = sizeof(checkType(&T::qt_check_for_QGADGET_macro)) == sizeof(void *), + IsGadgetOrDerivedFrom = true + }; }; template<typename T, typename Enable = void> - struct IsPointerToGadgetHelper { enum { Value = false }; }; + struct IsPointerToGadgetHelper { enum { IsRealGadget = false, IsGadgetOrDerivedFrom = false }; }; template<typename T> struct IsPointerToGadgetHelper<T*, typename T::QtGadgetHelper> @@ -1402,7 +1405,10 @@ namespace QtPrivate template <typename X> static char checkType(void (X::*)()); static void *checkType(void (T::*)()); - enum { Value = sizeof(checkType(&T::qt_check_for_QGADGET_macro)) == sizeof(void *) }; + enum { + IsRealGadget = sizeof(checkType(&T::qt_check_for_QGADGET_macro)) == sizeof(void *), + IsGadgetOrDerivedFrom = true + }; }; @@ -1435,12 +1441,12 @@ namespace QtPrivate static inline const QMetaObject *value() { return &T::staticMetaObject; } }; template<typename T> - struct MetaObjectForType<T, typename std::enable_if<IsGadgetHelper<T>::Value>::type> + struct MetaObjectForType<T, typename std::enable_if<IsGadgetHelper<T>::IsGadgetOrDerivedFrom>::type> { static inline const QMetaObject *value() { return &T::staticMetaObject; } }; template<typename T> - struct MetaObjectForType<T, typename QEnableIf<IsPointerToGadgetHelper<T>::Value>::Type> + struct MetaObjectForType<T, typename std::enable_if<IsPointerToGadgetHelper<T>::IsGadgetOrDerivedFrom>::type> { static inline const QMetaObject *value() { return &IsPointerToGadgetHelper<T>::BaseType::staticMetaObject; } }; @@ -1599,8 +1605,8 @@ namespace QtPrivate template <typename T, int = QtPrivate::IsPointerToTypeDerivedFromQObject<T>::Value ? QMetaType::PointerToQObject : - QtPrivate::IsGadgetHelper<T>::Value ? QMetaType::IsGadget : - QtPrivate::IsPointerToGadgetHelper<T>::Value ? QMetaType::PointerToGadget : + QtPrivate::IsGadgetHelper<T>::IsRealGadget ? QMetaType::IsGadget : + QtPrivate::IsPointerToGadgetHelper<T>::IsRealGadget ? QMetaType::PointerToGadget : QtPrivate::IsQEnumHelper<T>::Value ? QMetaType::IsEnumeration : 0> struct QMetaTypeIdQObject { @@ -1653,8 +1659,8 @@ namespace QtPrivate { | (IsWeakPointerToTypeDerivedFromQObject<T>::Value ? QMetaType::WeakPointerToQObject : 0) | (IsTrackingPointerToTypeDerivedFromQObject<T>::Value ? QMetaType::TrackingPointerToQObject : 0) | (std::is_enum<T>::value ? QMetaType::IsEnumeration : 0) - | (IsGadgetHelper<T>::Value ? QMetaType::IsGadget : 0) - | (IsPointerToGadgetHelper<T>::Value ? QMetaType::PointerToGadget : 0) + | (IsGadgetHelper<T>::IsGadgetOrDerivedFrom ? QMetaType::IsGadget : 0) + | (IsPointerToGadgetHelper<T>::IsGadgetOrDerivedFrom ? QMetaType::PointerToGadget : 0) }; }; diff --git a/tests/auto/corelib/kernel/qmetatype/tst_qmetatype.cpp b/tests/auto/corelib/kernel/qmetatype/tst_qmetatype.cpp index cc628ee26e..c6fd5d17c2 100644 --- a/tests/auto/corelib/kernel/qmetatype/tst_qmetatype.cpp +++ b/tests/auto/corelib/kernel/qmetatype/tst_qmetatype.cpp @@ -141,6 +141,14 @@ public: class CustomNonQObject {}; class GadgetDerived : public CustomGadget {}; +// cannot use Q_GADGET due to moc limitations but wants to behave like +// a Q_GADGET in Qml land +template<typename T> +class GadgetDerivedAndTyped : public CustomGadget {}; + +Q_DECLARE_METATYPE(GadgetDerivedAndTyped<int>) +Q_DECLARE_METATYPE(GadgetDerivedAndTyped<int>*) + void tst_QMetaType::defined() { QCOMPARE(int(QMetaTypeId2<QString>::Defined), 1); @@ -157,6 +165,10 @@ void tst_QMetaType::defined() QVERIFY(!QMetaTypeId2<CustomNonQObject>::Defined); QVERIFY(!QMetaTypeId2<CustomNonQObject*>::Defined); QVERIFY(!QMetaTypeId2<CustomGadget_NonDefaultConstructible>::Defined); + + // registered with Q_DECLARE_METATYPE + QVERIFY(QMetaTypeId2<GadgetDerivedAndTyped<int>>::Defined); + QVERIFY(QMetaTypeId2<GadgetDerivedAndTyped<int>*>::Defined); } struct Bar @@ -396,6 +408,10 @@ void tst_QMetaType::typeName_data() QTest::newRow("CustomGadget*") << ::qMetaTypeId<CustomGadget*>() << QString::fromLatin1("CustomGadget*"); QTest::newRow("CustomQObject::CustomQEnum") << ::qMetaTypeId<CustomQObject::CustomQEnum>() << QString::fromLatin1("CustomQObject::CustomQEnum"); QTest::newRow("Qt::ArrowType") << ::qMetaTypeId<Qt::ArrowType>() << QString::fromLatin1("Qt::ArrowType"); + + // template instance class derived from Q_GADGET enabled class + QTest::newRow("GadgetDerivedAndTyped<int>") << ::qMetaTypeId<GadgetDerivedAndTyped<int>>() << QString::fromLatin1("GadgetDerivedAndTyped<int>"); + QTest::newRow("GadgetDerivedAndTyped<int>*") << ::qMetaTypeId<GadgetDerivedAndTyped<int>*>() << QString::fromLatin1("GadgetDerivedAndTyped<int>*"); } void tst_QMetaType::typeName() @@ -1703,6 +1719,9 @@ void tst_QMetaType::metaObject_data() QTest::newRow("MyGadget*") << ::qMetaTypeId<MyGadget*>() << &MyGadget::staticMetaObject << false << true << false; QTest::newRow("MyEnum") << ::qMetaTypeId<MyGadget::MyEnum>() << &MyGadget::staticMetaObject << false << false << false; QTest::newRow("Qt::ScrollBarPolicy") << ::qMetaTypeId<Qt::ScrollBarPolicy>() << &QObject::staticQtMetaObject << false << false << false; + + QTest::newRow("GadgetDerivedAndTyped<int>") << ::qMetaTypeId<GadgetDerivedAndTyped<int>>() << &GadgetDerivedAndTyped<int>::staticMetaObject << true << false << false; + QTest::newRow("GadgetDerivedAndTyped<int>*") << ::qMetaTypeId<GadgetDerivedAndTyped<int>*>() << &GadgetDerivedAndTyped<int>::staticMetaObject << false << true << false; } |