From dbe9a8c9696428529cacb9dd4e004db99914b56e Mon Sep 17 00:00:00 2001 From: Olivier Goffart Date: Tue, 12 Apr 2016 16:05:10 +0200 Subject: Don't copy the functor object for each signal emission The behavior was different in the variadic template code and in the C++98 code. The code without variadic template support was not copying the functor object (e.g. a lambda) before calling it. However, in the variadic template section, QtPrivate::FunctorCall::call took the functor by value instead of by reference resulting in a copy. QtPrivate::FunctorCall::call is a helper function for QtPrivate::FunctionPointer::call which is only needed for variadic template expension. [ChangeLog][QtCore][QObject] If the compiler supports variadic templates, no longer copy functor connected to a signal each time the signal is emitted. Restoring the C++98 behavior. Task-number: QTBUG-52542 Change-Id: I3ca20ef6910893b8a288e70af7de4c7b69502173 Reviewed-by: Thiago Macieira --- tests/auto/corelib/kernel/qobject/tst_qobject.cpp | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'tests/auto/corelib/kernel/qobject/tst_qobject.cpp') diff --git a/tests/auto/corelib/kernel/qobject/tst_qobject.cpp b/tests/auto/corelib/kernel/qobject/tst_qobject.cpp index f3334b1222..5b89ef3792 100644 --- a/tests/auto/corelib/kernel/qobject/tst_qobject.cpp +++ b/tests/auto/corelib/kernel/qobject/tst_qobject.cpp @@ -147,6 +147,7 @@ private slots: void qmlConnect(); void exceptions(); void noDeclarativeParentChangedOnDestruction(); + void mutableFunctor(); }; struct QObjectCreatedOnShutdown @@ -6420,6 +6421,24 @@ void tst_QObject::noDeclarativeParentChangedOnDestruction() #endif } +struct MutableFunctor { + int count; + MutableFunctor() : count(0) {} + int operator()() { return ++count; } +}; + +void tst_QObject::mutableFunctor() +{ + ReturnValue o; + MutableFunctor functor; + QCOMPARE(functor.count, 0); + connect(&o, &ReturnValue::returnInt, functor); + QCOMPARE(emit o.returnInt(0), 1); + QCOMPARE(emit o.returnInt(0), 2); // each emit should increase the internal count + + QCOMPARE(functor.count, 0); // but the original object should have been copied at connect time +} + // Test for QtPrivate::HasQ_OBJECT_Macro Q_STATIC_ASSERT(QtPrivate::HasQ_OBJECT_Macro::Value); Q_STATIC_ASSERT(!QtPrivate::HasQ_OBJECT_Macro::Value); -- cgit v1.2.3