From 76e25bdfdf324a85234b7e7273e0956107f84195 Mon Sep 17 00:00:00 2001
From: Volker Hilsheimer <volker.hilsheimer@qt.io>
Date: Sat, 29 Apr 2023 22:32:21 +0200
Subject: Remove QStaticSlotObject, use QFunctorSlotObject instead

The two slot object types are identical as long as we use a universal
reference and perfect forwarding in the respective connect overloads.

Change-Id: I999d71707dd045a17156e3bfecd371da7979beb1
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
---
 src/corelib/kernel/qobject.h      | 20 ++++++++++----------
 src/corelib/kernel/qobject_impl.h | 24 ------------------------
 2 files changed, 10 insertions(+), 34 deletions(-)

diff --git a/src/corelib/kernel/qobject.h b/src/corelib/kernel/qobject.h
index 53c6de654f..95322a9dbd 100644
--- a/src/corelib/kernel/qobject.h
+++ b/src/corelib/kernel/qobject.h
@@ -226,20 +226,20 @@ public:
     //connect to a function pointer  (not a member)
     template <typename Func1, typename Func2>
     static inline typename std::enable_if<int(QtPrivate::FunctionPointer<Func2>::ArgumentCount) >= 0, QMetaObject::Connection>::type
-            connect(const typename QtPrivate::FunctionPointer<Func1>::Object *sender, Func1 signal, Func2 slot)
+            connect(const typename QtPrivate::FunctionPointer<Func1>::Object *sender, Func1 signal, Func2 &&slot)
     {
-        return connect(sender, signal, sender, slot, Qt::DirectConnection);
+        return connect(sender, signal, sender, std::forward<Func2>(slot), Qt::DirectConnection);
     }
 
     //connect to a function pointer  (not a member)
     template <typename Func1, typename Func2>
-    static inline typename std::enable_if<int(QtPrivate::FunctionPointer<Func2>::ArgumentCount) >= 0 &&
-                                          !QtPrivate::FunctionPointer<Func2>::IsPointerToMemberFunction, QMetaObject::Connection>::type
-            connect(const typename QtPrivate::FunctionPointer<Func1>::Object *sender, Func1 signal, const QObject *context, Func2 slot,
+    static inline typename std::enable_if<int(QtPrivate::FunctionPointer<std::decay_t<Func2>>::ArgumentCount) >= 0 &&
+                                          !QtPrivate::FunctionPointer<std::decay_t<Func2>>::IsPointerToMemberFunction, QMetaObject::Connection>::type
+            connect(const typename QtPrivate::FunctionPointer<Func1>::Object *sender, Func1 signal, const QObject *context, Func2 &&slot,
                     Qt::ConnectionType type = Qt::AutoConnection)
     {
         typedef QtPrivate::FunctionPointer<Func1> SignalType;
-        typedef QtPrivate::FunctionPointer<Func2> SlotType;
+        typedef QtPrivate::FunctionPointer<std::decay_t<Func2>> SlotType;
 
         static_assert(QtPrivate::HasQ_OBJECT_Macro<typename SignalType::Object>::Value,
                           "No Q_OBJECT in the class with the signal");
@@ -257,9 +257,9 @@ public:
             types = QtPrivate::ConnectionTypes<typename SignalType::Arguments>::types();
 
         return connectImpl(sender, reinterpret_cast<void **>(&signal), context, nullptr,
-                           new QtPrivate::QStaticSlotObject<Func2,
+                           new QtPrivate::QFunctorSlotObject<Func2,
                                                  typename QtPrivate::List_Left<typename SignalType::Arguments, SlotType::ArgumentCount>::Value,
-                                                 typename SignalType::ReturnType>(slot),
+                                                 typename SignalType::ReturnType>(std::forward<Func2>(slot)),
                            type, types, &SignalType::Object::staticMetaObject);
     }
 
@@ -269,9 +269,9 @@ public:
         QtPrivate::FunctionPointer<Func2>::ArgumentCount == -1 &&
         !std::is_convertible_v<Func2, const char*>, // don't match old-style connect
     QMetaObject::Connection>::type
-            connect(const typename QtPrivate::FunctionPointer<Func1>::Object *sender, Func1 signal, Func2 slot)
+            connect(const typename QtPrivate::FunctionPointer<Func1>::Object *sender, Func1 signal, Func2 &&slot)
     {
-        return connect(sender, signal, sender, std::move(slot), Qt::DirectConnection);
+        return connect(sender, signal, sender, std::forward<Func2>(slot), Qt::DirectConnection);
     }
 
     //connect to a functor, with a "context" object defining in which event loop is going to be executed
diff --git a/src/corelib/kernel/qobject_impl.h b/src/corelib/kernel/qobject_impl.h
index 4d6830a3cc..b57d7e50cc 100644
--- a/src/corelib/kernel/qobject_impl.h
+++ b/src/corelib/kernel/qobject_impl.h
@@ -37,30 +37,6 @@ namespace QtPrivate {
     { static const int *types() { return nullptr; } };
     template <typename... Args> struct ConnectionTypes<List<Args...>, true>
     { static const int *types() { static const int t[sizeof...(Args) + 1] = { (QtPrivate::QMetaTypeIdHelper<Args>::qt_metatype_id())..., 0 }; return t; } };
-
-    // implementation of QSlotObjectBase for which the slot is a static function
-    // Args and R are the List of arguments and the return type of the signal to which the slot is connected.
-    template<typename Func, typename Args, typename R> class QStaticSlotObject : public QSlotObjectBase
-    {
-        typedef QtPrivate::FunctionPointer<Func> FuncType;
-        Func function;
-        static void impl(int which, QSlotObjectBase *this_, QObject *r, void **a, bool *ret)
-        {
-            switch (which) {
-            case Destroy:
-                delete static_cast<QStaticSlotObject*>(this_);
-                break;
-            case Call:
-                FuncType::template call<Args, R>(static_cast<QStaticSlotObject*>(this_)->function, r, a);
-                break;
-            case Compare:   // not implemented
-            case NumOperations:
-                Q_UNUSED(ret);
-            }
-        }
-    public:
-        explicit QStaticSlotObject(Func f) : QSlotObjectBase(&impl), function(f) {}
-    };
 }
 
 
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