Add QMetaObject::invokeMethod() overloads for function pointers

The new overloads do not accept parameters for the invoked function, this
use case is handled by using lambda.
Overloads for non member function pointers and functors are separated as
the return type is not retrieved in the same way.
Move QSlotObjectBase, QSlotObject and QFunctorSlotObject from
qobject_impl.h to qobjectdefs_impl.h in order to make them available in
qobjectdefs.h.
Update autotests of previous overloads because of a soft break in source
compatibility: passing null literals (0, NULL, nullptr, etc.) for the
second parameter of invokeMethod() is not supported anymore.

[ChangeLog][QtCore] Added QMetaObject::invokeMethod() overloads for function
pointers.

Task-number: QTBUG-37253
Change-Id: I6fb67e086d315ae393ce32743c4eb1abd6cc9139
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 88 insertions, 1 deletions

diff --git a/src/corelib/kernel/qobjectdefs.h b/src/corelib/kernel/qobjectdefs.h
index ea4046df55..b6307fcfcf 100644
--- a/src/corelib/kernel/qobjectdefs.h
+++ b/src/corelib/kernel/qobjectdefs.h
@@ -57,7 +57,6 @@ struct QArrayData;
 typedef QArrayData QByteArrayData;
 
 class QString;
-
 #ifndef Q_MOC_OUTPUT_REVISION
 #define Q_MOC_OUTPUT_REVISION 67
 #endif
@@ -466,6 +465,91 @@ struct Q_CORE_EXPORT QMetaObject
                 val1, val2, val3, val4, val5, val6, val7, val8, val9);
     }
 
+#ifdef Q_QDOC
+    template<typename PointerToMemberFunction, typename MemberFunctionReturnType>
+    static bool invokeMethod(QObject *receiver, PointerToMemberFunction function, Qt::ConnectionType type = Qt::AutoConnection, MemberFunctionReturnType *ret = nullptr);
+    template<typename PointerToMemberFunction, typename MemberFunctionReturnType>
+    static bool invokeMethod(QObject *receiver, PointerToMemberFunction function, MemberFunctionReturnType *ret);
+    template<typename Functor, typename FunctorReturnType>
+    static bool invokeMethod(QObject *context, Functor function, Qt::ConnectionType type = Qt::AutoConnection, FunctorReturnType *ret = nullptr);
+    template<typename Functor, typename FunctorReturnType>
+    static bool invokeMethod(QObject *context, Functor function, FunctorReturnType *ret);
+#else
+
+    // invokeMethod() for member function pointer
+    template <typename Func>
+    static typename std::enable_if<QtPrivate::FunctionPointer<Func>::IsPointerToMemberFunction
+                                   && !std::is_convertible<Func, const char*>::value
+                                   && QtPrivate::FunctionPointer<Func>::ArgumentCount == 0, bool>::type
+    invokeMethod(typename QtPrivate::FunctionPointer<Func>::Object *object,
+                 Func function,
+                 Qt::ConnectionType type = Qt::AutoConnection,
+                 typename QtPrivate::FunctionPointer<Func>::ReturnType *ret = nullptr)
+    {
+        return invokeMethodImpl(object, new QtPrivate::QSlotObjectWithNoArgs<Func>(function), type, ret);
+    }
+
+    template <typename Func>
+    static typename std::enable_if<QtPrivate::FunctionPointer<Func>::IsPointerToMemberFunction
+                                   && !std::is_convertible<Func, const char*>::value
+                                   && QtPrivate::FunctionPointer<Func>::ArgumentCount == 0, bool>::type
+    invokeMethod(typename QtPrivate::FunctionPointer<Func>::Object *object,
+                 Func function,
+                 typename QtPrivate::FunctionPointer<Func>::ReturnType *ret)
+    {
+        return invokeMethodImpl(object, new QtPrivate::QSlotObjectWithNoArgs<Func>(function), Qt::AutoConnection, ret);
+    }
+
+    // invokeMethod() for function pointer (not member)
+    template <typename Func>
+    static typename std::enable_if<!QtPrivate::FunctionPointer<Func>::IsPointerToMemberFunction
+                                   && !std::is_convertible<Func, const char*>::value
+                                   && QtPrivate::FunctionPointer<Func>::ArgumentCount == 0, bool>::type
+    invokeMethod(QObject *context, Func function,
+                 Qt::ConnectionType type = Qt::AutoConnection,
+                 typename QtPrivate::FunctionPointer<Func>::ReturnType *ret = nullptr)
+    {
+        return invokeMethodImpl(context, new QtPrivate::QFunctorSlotObjectWithNoArgsImplicitReturn<Func>(function), type, ret);
+    }
+
+    template <typename Func>
+    static typename std::enable_if<!QtPrivate::FunctionPointer<Func>::IsPointerToMemberFunction
+                                   && !std::is_convertible<Func, const char*>::value
+                                   && QtPrivate::FunctionPointer<Func>::ArgumentCount == 0, bool>::type
+    invokeMethod(QObject *context, Func function,
+                 typename QtPrivate::FunctionPointer<Func>::ReturnType *ret)
+    {
+        return invokeMethodImpl(context, new QtPrivate::QFunctorSlotObjectWithNoArgsImplicitReturn<Func>(function), Qt::AutoConnection, ret);
+    }
+
+    // invokeMethod() for Functor
+    template <typename Func>
+    static typename std::enable_if<!QtPrivate::FunctionPointer<Func>::IsPointerToMemberFunction
+                                   && QtPrivate::FunctionPointer<Func>::ArgumentCount == -1
+                                   && !std::is_convertible<Func, const char*>::value, bool>::type
+    invokeMethod(QObject *context, Func function,
+                 Qt::ConnectionType type = Qt::AutoConnection, decltype(function()) *ret = nullptr)
+    {
+        return invokeMethodImpl(context,
+                                new QtPrivate::QFunctorSlotObjectWithNoArgs<Func, decltype(function())>(function),
+                                type,
+                                ret);
+    }
+
+    template <typename Func>
+    static typename std::enable_if<!QtPrivate::FunctionPointer<Func>::IsPointerToMemberFunction
+                                   && QtPrivate::FunctionPointer<Func>::ArgumentCount == -1
+                                   && !std::is_convertible<Func, const char*>::value, bool>::type
+    invokeMethod(QObject *context, Func function, typename std::result_of<Func()>::type *ret)
+    {
+        return invokeMethodImpl(context,
+                                new QtPrivate::QFunctorSlotObjectWithNoArgs<Func, decltype(function())>(function),
+                                Qt::AutoConnection,
+                                ret);
+    }
+
+#endif
+
     QObject *newInstance(QGenericArgument val0 = QGenericArgument(Q_NULLPTR),
                          QGenericArgument val1 = QGenericArgument(),
                          QGenericArgument val2 = QGenericArgument(),
@@ -505,6 +589,9 @@ struct Q_CORE_EXPORT QMetaObject
         const QMetaObject * const *relatedMetaObjects;
         void *extradata; //reserved for future use
     } d;
+
+private:
+    static bool invokeMethodImpl(QObject *object, QtPrivate::QSlotObjectBase *slot, Qt::ConnectionType type, void *ret);
 };
 
 class Q_CORE_EXPORT QMetaObject::Connection {