Add QTimer::connectTo(), a shorthand way of connecting to timeout()

There are a couple of Qt classes where you almost always use the
same signal, for example QTimer::timeout, QPushButton::clicked,
and QAction::triggered.

Simply doing timer.connectTo([]{}) is much more convenient, less
tedious and even fun.

Not overloading connect() as it would be confusing to see the
receiver as first argument.

And not naming it onTimeout, as that's a popular way of doing it in
other frameworks. People would assume you could use on* with any signal.
If we ever have on* it should be all or nothing.

[ChangeLog][QtCore] Added QTimer::connectTo(), a shorthand way of
connecting to the timeout() signal.

Change-Id: Ida57e5442b13d50972ed585c3ea7be07e3d8e8d2
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/src/corelib/kernel/qtimer.h b/src/corelib/kernel/qtimer.h
index e6db586aa0..7825bb0798 100644
--- a/src/corelib/kernel/qtimer.h
+++ b/src/corelib/kernel/qtimer.h
@@ -96,6 +96,12 @@ public:
     static void singleShot(int msec, const QObject *context, Functor functor);
     template<typename Functor, int>
     static void singleShot(int msec, Qt::TimerType timerType, const QObject *context, Functor functor);
+    template <typename Functor>
+    QMetaObject::Connection connectTo(Functor slot, Qt::ConnectionType connectionType = Qt::AutoConnection);
+    template <typename Functor>
+    QMetaObject::Connection connectTo(const QObject *context, Functor slot, Qt::ConnectionType connectionType = Qt::AutoConnection);
+    template <typename PointerToMemberFunction>
+    QMetaObject::Connection connectTo(const QObject *receiver, PointerToMemberFunction slot, Qt::ConnectionType connectionType = Qt::AutoConnection);
 #else
     // singleShot to a QObject slot
     template <typename Duration, typename Func1>
@@ -152,6 +158,13 @@ public:
                        new QtPrivate::QFunctorSlotObject<Func1, 0,
                             typename QtPrivate::List_Left<void, 0>::Value, void>(std::move(slot)));
     }
+
+    template <typename ... Args>
+    QMetaObject::Connection connectTo(Args && ...args)
+    {
+        return QObject::connect(this, &QTimer::timeout, std::forward<Args>(args)... );
+    }
+
 #endif
 
 public Q_SLOTS: