QMetaObject: add a new, variadic invoke/invokeMethod/newInstance

[ChangeLog][QtCore][Meta Objects] The QMetaObject::invokeMethod() taking
a method name by string, QMetaObject::newInstance(), and
QMetaMethod::invoke() now support more than 10 arguments.

[ChangeLog][QtCore][Meta Objects] The use of the Q_ARG and Q_RETURN_ARG
macros is now optional with QMetaObject::invokeMethod(),
QMetaObject::newInstance(), and QMetaMethod::invoke(): the type name
will be obtained from the C++ type (the same as QMetaType). The function
qReturnArg() can be used in place of the Q_RETURN_ARG macro. The macros
are still useful in rare conditions where the type was typedef'ed from
its original name.

Change-Id: I36b24183fbd041179f2ffffd17022a2b48c7639b
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

1 files changed, 48 insertions, 3 deletions

diff --git a/src/corelib/kernel/qmetaobject.h b/src/corelib/kernel/qmetaobject.h
index 0740acef60..735f26caa2 100644
--- a/src/corelib/kernel/qmetaobject.h
+++ b/src/corelib/kernel/qmetaobject.h
@@ -45,6 +45,7 @@ public:
 
     inline const QMetaObject *enclosingMetaObject() const { return mobj; }
 
+#if QT_VERSION <= QT_VERSION_CHECK(7, 0, 0)
     bool invoke(QObject *object,
                 Qt::ConnectionType connectionType,
                 QGenericReturnArgument returnValue,
@@ -76,7 +77,7 @@ public:
     }
     inline bool invoke(QObject *object,
                        Qt::ConnectionType connectionType,
-                       QGenericArgument val0 = QGenericArgument(nullptr),
+                       QGenericArgument val0,
                        QGenericArgument val1 = QGenericArgument(),
                        QGenericArgument val2 = QGenericArgument(),
                        QGenericArgument val3 = QGenericArgument(),
@@ -91,7 +92,7 @@ public:
                       val0, val1, val2, val3, val4, val5, val6, val7, val8, val9);
     }
     inline bool invoke(QObject *object,
-                       QGenericArgument val0 = QGenericArgument(nullptr),
+                       QGenericArgument val0,
                        QGenericArgument val1 = QGenericArgument(),
                        QGenericArgument val2 = QGenericArgument(),
                        QGenericArgument val3 = QGenericArgument(),
@@ -118,7 +119,7 @@ public:
                         QGenericArgument val8 = QGenericArgument(),
                         QGenericArgument val9 = QGenericArgument()) const;
     inline bool invokeOnGadget(void *gadget,
-                               QGenericArgument val0 = QGenericArgument(nullptr),
+                               QGenericArgument val0,
                                QGenericArgument val1 = QGenericArgument(),
                                QGenericArgument val2 = QGenericArgument(),
                                QGenericArgument val3 = QGenericArgument(),
@@ -132,6 +133,48 @@ public:
         return invokeOnGadget(gadget, QGenericReturnArgument(),
                               val0, val1, val2, val3, val4, val5, val6, val7, val8, val9);
     }
+#endif
+
+    template <typename... Args> QtPrivate::Invoke::IfNotOldStyleArgs<bool, Args...>
+    invoke(QObject *obj, Qt::ConnectionType c, QMetaMethodReturnArgument r,
+           Args &&... arguments) const
+    {
+        auto h = QtPrivate::invokeMethodHelper(r, std::forward<Args>(arguments)...);
+        return invokeImpl(*this, obj, c, h.parameterCount(), h.parameters.data(),
+                          h.typeNames.data());
+    }
+
+    template <typename... Args> QtPrivate::Invoke::IfNotOldStyleArgs<bool, Args...>
+    invoke(QObject *obj, Qt::ConnectionType c, Args &&... arguments) const
+    {
+        return invoke(obj, c, QMetaMethodReturnArgument{}, std::forward<Args>(arguments)...);
+    }
+
+    template <typename... Args> QtPrivate::Invoke::IfNotOldStyleArgs<bool, Args...>
+    invoke(QObject *obj, QMetaMethodReturnArgument r, Args &&... arguments) const
+    {
+        return invoke(obj, Qt::AutoConnection, r, std::forward<Args>(arguments)...);
+    }
+
+    template <typename... Args> QtPrivate::Invoke::IfNotOldStyleArgs<bool, Args...>
+    invoke(QObject *obj, Args &&... arguments) const
+    {
+        return invoke(obj, Qt::AutoConnection, std::forward<Args>(arguments)...);
+    }
+
+    template <typename... Args> QtPrivate::Invoke::IfNotOldStyleArgs<bool, Args...>
+    invokeOnGadget(void *gadget, QMetaMethodReturnArgument r, Args &&... arguments) const
+    {
+        auto h = QtPrivate::invokeMethodHelper(r, std::forward<Args>(arguments)...);
+        return invokeImpl(*this, gadget, Qt::ConnectionType(-1), h.parameterCount(),
+                          h.parameters.data(), h.typeNames.data());
+    }
+
+    template <typename... Args> QtPrivate::Invoke::IfNotOldStyleArgs<bool, Args...>
+    invokeOnGadget(void *gadget, Args &&... arguments) const
+    {
+        return invokeOnGadget(gadget, QMetaMethodReturnArgument{}, std::forward<Args>(arguments)...);
+    }
 
     inline bool isValid() const { return mobj != nullptr; }
 
@@ -146,6 +189,8 @@ public:
     }
 
 private:
+    static bool invokeImpl(QMetaMethod self, void *target, Qt::ConnectionType, qsizetype paramCount,
+                           const void *const *parameters, const char *const *typeNames);
     static QMetaMethod fromSignalImpl(const QMetaObject *, void **);
     static QMetaMethod fromRelativeMethodIndex(const QMetaObject *mobj, int index);
     static QMetaMethod fromRelativeConstructorIndex(const QMetaObject *mobj, int index);