QEvent: start to de-inline copy ctor and clone() of all subclasses

There's no advantage to them being inline: Absent de-virtualisation,
clone() is only supposed to be called through the vtable, and the copy
ctor is only supposed to be used in the implementation of clone().

And when the compiler de-virtualises, we don't want the code
duplication associated with inlining.

Enforce this by introducing new macros to hide the boilerplate.

This fixes missing out-of-line dtors in:
- QSinglePointEvent
- QApplicationStateChangeEvent
- QFutureCallOutEvent

Wrong covariant return in:
- QFutureCallOutEvent

And missing clone() reimplementations in:
- QCloseEvent
- QIconDragEvent
- QShowEvent
- QHideEvent
- QDragEnterEvent
- QDragLeaveEvent

While these don't carry extra data or members, a dynamic_cast of the
result of clone() as well as using the expected covariant return value
would fail:

   QShowEvent *e = ~~~;
   QShowEvent *e2 = e->clone(); // ERROR: converting QEvent* to QShowEvent*

Check that reimplementing clone() is binary compatible (covariant
returns may change the numerical pointer value returned, cf.
https://community.kde.org/Policies/Binary_Compatibility_Issues_With_C%2B%2B).

The copy-assignment operator stays inline for the time being, as the
goal is to = delete it in the future.

This patch covers, roughly, QtCore and QtGui.

[ChangeLog][QtGui][QEvent subclasses] Fixed missing clone()
reimplementations on QCloseEvent, QIconDragEvent, QShowEvent,
QHideEvent, QDragEnterEvent, and QDragLeaveEvent.

Task-number: QTBUG-45582
Task-number: QTBUG-97601
Change-Id: Ib8a0519dbe85a7a8da61050d48be338004dfa69a
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

2 files changed, 83 insertions, 2 deletions

diff --git a/tests/auto/gui/kernel/qevent/CMakeLists.txt b/tests/auto/gui/kernel/qevent/CMakeLists.txt
index 2bb22eb469..7b37b0c51a 100644
--- a/tests/auto/gui/kernel/qevent/CMakeLists.txt
+++ b/tests/auto/gui/kernel/qevent/CMakeLists.txt
@@ -7,4 +7,7 @@
 qt_internal_add_test(tst_qevent
     SOURCES
         tst_qevent.cpp
+    PUBLIC_LIBRARIES
+        Qt::Gui
+        Qt::CorePrivate
 )
diff --git a/tests/auto/gui/kernel/qevent/tst_qevent.cpp b/tests/auto/gui/kernel/qevent/tst_qevent.cpp
index 6542ed5ad3..cc8ac6ea6c 100644
--- a/tests/auto/gui/kernel/qevent/tst_qevent.cpp
+++ b/tests/auto/gui/kernel/qevent/tst_qevent.cpp
@@ -29,8 +29,73 @@
 
 #include <QTest>
 
-#include <QtCore/qcoreapplication.h>
-#include <QtCore/qcoreevent.h>
+#include <QtGui/qguiapplication.h>
+#include <QtGui/qevent.h>
+#include <QtCore/private/qfutureinterface_p.h>
+
+#define FOR_EACH_CORE_EVENT(X) \
+    /* qcoreevent.h */ \
+    X(QEvent, (QEvent::None)) \
+    X(QTimerEvent, (42)) \
+    X(QChildEvent, (QEvent::ChildAdded, nullptr)) \
+    X(QDynamicPropertyChangeEvent, ("size")) \
+    X(QDeferredDeleteEvent, ()) \
+    /* qfutureinterface_p.h */ \
+    X(QFutureCallOutEvent, ()) \
+    /* end */
+
+#define FOR_EACH_GUI_EVENT(X) \
+    /* qevent.h */ \
+    X(QInputEvent, (QEvent::None, nullptr)) \
+    X(QPointerEvent, (QEvent::None, nullptr)) \
+    /* doesn't work with nullptr: */ \
+    X(QSinglePointEvent, (QEvent::None, QPointingDevice::primaryPointingDevice(), {}, {}, {}, {}, {}, {})) \
+    X(QEnterEvent, ({}, {}, {})) \
+    X(QMouseEvent, (QEvent::None, {}, {}, {}, {}, {}, {}, {}, QPointingDevice::primaryPointingDevice())) \
+    X(QHoverEvent, (QEvent::None, {}, {}, QPointF{})) \
+    X(QWheelEvent, ({}, {}, {}, {}, {}, {}, {}, {})) \
+    X(QTabletEvent, (QEvent::None, QPointingDevice::primaryPointingDevice(), {}, {}, {}, {}, {}, {}, {}, {}, {}, {}, {})) \
+    X(QNativeGestureEvent, ({}, QPointingDevice::primaryPointingDevice(), 0, {}, {}, {}, {}, {})) \
+    X(QKeyEvent, (QEvent::None, 0, {})) \
+    X(QFocusEvent, (QEvent::None)) \
+    X(QPaintEvent, (QRect{0, 0, 100, 100})) \
+    X(QMoveEvent, ({}, {})) \
+    X(QExposeEvent, ({})) \
+    X(QPlatformSurfaceEvent, ({})) \
+    X(QResizeEvent, ({}, {})) \
+    X(QCloseEvent, ()) \
+    X(QIconDragEvent, ()) \
+    X(QShowEvent, ()) \
+    X(QHideEvent, ()) \
+    QT_WARNING_PUSH \
+    QT_WARNING_DISABLE_DEPRECATED \
+    X(QContextMenuEvent, (QContextMenuEvent::Reason::Keyboard, {})) \
+    QT_WARNING_POP \
+    X(QInputMethodEvent, ()) \
+    X(QInputMethodQueryEvent, ({})) \
+    X(QDropEvent, ({}, {}, {}, {}, {})) \
+    X(QDragMoveEvent, ({}, {}, {}, {}, {})) \
+    X(QDragEnterEvent, ({}, {}, {}, {}, {})) \
+    X(QDragLeaveEvent, ()) \
+    X(QHelpEvent, ({}, {}, {})) \
+    X(QStatusTipEvent, ({})) \
+    X(QWhatsThisClickedEvent, ({})) \
+    X(QActionEvent, (0, nullptr)) \
+    X(QFileOpenEvent, (QString{})) \
+    X(QToolBarChangeEvent, (false)) \
+    X(QShortcutEvent, ({}, 0)) \
+    X(QWindowStateChangeEvent, ({})) \
+    X(QTouchEvent, (QEvent::None)) \
+    X(QScrollPrepareEvent, ({})) \
+    X(QScrollEvent, ({}, {}, {})) \
+    X(QScreenOrientationChangeEvent, (nullptr, {})) \
+    X(QApplicationStateChangeEvent, ({})) \
+    /* end */
+
+#define FOR_EACH_EVENT(X) \
+    FOR_EACH_CORE_EVENT(X) \
+    FOR_EACH_GUI_EVENT(X) \
+    /* end */
 
 class tst_QEvent : public QObject
 {
@@ -40,6 +105,7 @@ public:
     ~tst_QEvent();
 
 private slots:
+    void clone() const;
     void registerEventType_data();
     void registerEventType();
     void exhaustEventTypeRegistration(); // keep behind registerEventType() test
@@ -55,6 +121,18 @@ tst_QEvent::tst_QEvent()
 tst_QEvent::~tst_QEvent()
 { }
 
+void tst_QEvent::clone() const
+{
+#define ACTION(Type, Init) do { \
+        const std::unique_ptr<const Type> e(new Type Init); \
+        auto c = e->clone(); \
+        static_assert(std::is_same_v<decltype(c), Type *>); \
+        delete c; \
+    } while (0);
+
+    FOR_EACH_EVENT(ACTION)
+}
+
 void tst_QEvent::registerEventType_data()
 {
     QTest::addColumn<int>("hint");