1 files changed, 40 insertions, 5 deletions
diff --git a/src/corelib/kernel/qobjectdefs_impl.h b/src/corelib/kernel/qobjectdefs_impl.h
index 1452e720ad..4f44d9204e 100644
--- a/src/corelib/kernel/qobjectdefs_impl.h
+++ b/src/corelib/kernel/qobjectdefs_impl.h
@@ -1,6 +1,7 @@
 /****************************************************************************
 **
 ** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Copyright (C) 2013 Olivier Goffart <ogoffart@woboq.com>
 ** Contact: http://www.qt-project.org/legal
 **
 ** This file is part of the QtCore module of the Qt Toolkit.
@@ -45,7 +46,10 @@
 #error Do not include qobjectdefs_impl.h directly
 #endif
 
-QT_BEGIN_HEADER
+#if 0
+#pragma qt_sync_skip_header_check
+#pragma qt_sync_stop_processing
+#endif
 
 QT_BEGIN_NAMESPACE
 
@@ -90,7 +94,7 @@ namespace QtPrivate {
     template <typename T>
     struct ApplyReturnValue {
         void *data;
-        ApplyReturnValue(void *data_) : data(data_) {}
+        explicit ApplyReturnValue(void *data_) : data(data_) {}
     };
     template<typename T, typename U>
     void operator,(const T &value, const ApplyReturnValue<U> &container) {
@@ -594,13 +598,44 @@ namespace QtPrivate {
         enum { value = AreArgumentsCompatible<typename RemoveConstRef<Arg1>::Type, typename RemoveConstRef<Arg2>::Type>::value
                     && CheckCompatibleArguments<List<Tail1...>, List<Tail2...>>::value };
     };
+#endif
+
+#if defined(Q_COMPILER_DECLTYPE) && defined(Q_COMPILER_VARIADIC_TEMPLATES)
+    /*
+       Find the maximum number of arguments a functor object can take and be still compatible with
+       the arguments from the signal.
+       Value is the number of arguments, or -1 if nothing matches.
+     */
+    template <typename Functor, typename ArgList> struct ComputeFunctorArgumentCount;
+
+    template <typename Functor, typename ArgList, bool Done> struct ComputeFunctorArgumentCountHelper
+    { enum { Value = -1 }; };
+    template <typename Functor, typename First, typename... ArgList>
+    struct ComputeFunctorArgumentCountHelper<Functor, List<First, ArgList...>, false>
+        : ComputeFunctorArgumentCount<Functor,
+            typename List_Left<List<First, ArgList...>, sizeof...(ArgList)>::Value> {};
+
+    template <typename Functor, typename... ArgList> struct ComputeFunctorArgumentCount<Functor, List<ArgList...>>
+    {
+        template <typename D> static D dummy();
+        template <typename F> static auto test(F f) -> decltype(((f.operator()((dummy<ArgList>())...)), int()));
+        static char test(...);
+        enum {
+            Ok = sizeof(test(dummy<Functor>())) == sizeof(int),
+            Value = Ok ? sizeof...(ArgList) : int(ComputeFunctorArgumentCountHelper<Functor, List<ArgList...>, Ok>::Value)
+        };
+    };
 
+    /* get the return type of a functor, given the signal argument list  */
+    template <typename Functor, typename ArgList> struct FunctorReturnType;
+    template <typename Functor, typename ... ArgList> struct FunctorReturnType<Functor, List<ArgList...>> {
+        template <typename D> static D dummy();
+        typedef decltype(dummy<Functor>().operator()((dummy<ArgList>())...)) Value;
+    };
 #endif
-}
 
+}
 
 QT_END_NAMESPACE
 
-QT_END_HEADER
-
 #endif