QtWidgets: Fix enter/leave events on popup menus

If the sloppy menu popups - send the leave event to the last active
menu (except Cocoa), because only currect active menu gets enter/leave
events (currently Cocoa is an exception).

Check that the menu really has a mouse before hiding the sloppy menu -
don't rely on enter events.

This patch removes some unnecessary synthetic mouse enter/leave events
from QMenu which causes event duplications with different mouse cursor
position.

Refactor sloppy menu timer handling - start or restart timers on mouse
move events. Enter/leave events are not reliable.

Fixes:
- better enter/leave events handling for native widget actions,
- reduce duplicated enter/leave events for menu actions,
- better handle torn off sloppy menus.

Partially reverts: 0ed68f3f58c63bd1496cb268bd83881da180051f
Amends: 57ecd5aeeb1f609206933be66b92fcdf703703d7

Task-number: QTBUG-53068
Change-Id: I7ad56ac1619db124915d373fab82d0512d44c90e
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

4 files changed, 74 insertions, 74 deletions

diff --git a/src/widgets/kernel/qwidgetwindow.cpp b/src/widgets/kernel/qwidgetwindow.cpp
index aa7bcc2ef8..95f63025fb 100644
--- a/src/widgets/kernel/qwidgetwindow.cpp
+++ b/src/widgets/kernel/qwidgetwindow.cpp
@@ -381,7 +381,14 @@ void QWidgetWindow::handleEnterLeaveEvent(QEvent *event)
         const QEnterEvent *ee = static_cast<QEnterEvent *>(event);
         QWidget *child = m_widget->childAt(ee->pos());
         QWidget *receiver = child ? child : m_widget.data();
-        QApplicationPrivate::dispatchEnterLeave(receiver, 0, ee->screenPos());
+        QWidget *leave = Q_NULLPTR;
+        if (QApplicationPrivate::inPopupMode() && receiver == m_widget
+                && qt_last_mouse_receiver != m_widget) {
+            // This allows to deliver the leave event to the native widget
+            // action on first-level menu.
+            leave = qt_last_mouse_receiver;
+        }
+        QApplicationPrivate::dispatchEnterLeave(receiver, leave, ee->screenPos());
         qt_last_mouse_receiver = receiver;
     }
 }
@@ -471,34 +478,31 @@ void QWidgetWindow::handleMouseEvent(QMouseEvent *event)
                 receiver = popupChild;
             if (receiver != activePopupWidget)
                 widgetPos = receiver->mapFromGlobal(event->globalPos());
-            QWidget *alien = receiver;
 
 #if !defined(Q_OS_OSX) && !defined(Q_OS_IOS) // Cocoa tracks popups
             const bool reallyUnderMouse = activePopupWidget->rect().contains(mapped);
             const bool underMouse = activePopupWidget->underMouse();
-            if (activePopupWidget != m_widget || (!underMouse && qt_button_down)) {
-                // If active popup menu is not the first-level popup menu then we must emulate enter/leave events,
-                // because first-level popup menu grabs the mouse and enter/leave events are delivered only to it
-                // by QPA. Make an exception for first-level popup menu when the mouse button is pressed on widget.
-                if (underMouse != reallyUnderMouse) {
-                    if (reallyUnderMouse) {
+            if (underMouse != reallyUnderMouse) {
+                if (reallyUnderMouse) {
+                    const QPoint receiverMapped = receiver->mapFromGlobal(event->screenPos().toPoint());
+                    // Prevent negative mouse position on enter event - this event
+                    // should be properly handled in "handleEnterLeaveEvent()".
+                    if (receiverMapped.x() >= 0 && receiverMapped.y() >= 0) {
                         QApplicationPrivate::dispatchEnterLeave(receiver, Q_NULLPTR, event->screenPos());
                         qt_last_mouse_receiver = receiver;
-                    } else {
-                        QApplicationPrivate::dispatchEnterLeave(Q_NULLPTR, qt_last_mouse_receiver, event->screenPos());
-                        qt_last_mouse_receiver = receiver;
-                        receiver = activePopupWidget;
                     }
+                } else {
+                    QApplicationPrivate::dispatchEnterLeave(Q_NULLPTR, qt_last_mouse_receiver, event->screenPos());
+                    qt_last_mouse_receiver = receiver;
+                    receiver = activePopupWidget;
                 }
-            } else if (!reallyUnderMouse) {
-                alien = Q_NULLPTR;
             }
 #endif
 
             QMouseEvent e(event->type(), widgetPos, event->windowPos(), event->screenPos(),
                           event->button(), event->buttons(), event->modifiers(), event->source());
             e.setTimestamp(event->timestamp());
-            QApplicationPrivate::sendMouseEvent(receiver, &e, alien, receiver->window(), &qt_button_down, qt_last_mouse_receiver);
+            QApplicationPrivate::sendMouseEvent(receiver, &e, receiver, receiver->window(), &qt_button_down, qt_last_mouse_receiver);
             qt_last_mouse_receiver = receiver;
         } else {
             // close disabled popups when a mouse button is pressed or released
diff --git a/src/widgets/widgets/qmenu.cpp b/src/widgets/widgets/qmenu.cpp
index c194547f2d..2fd5340f3b 100644
--- a/src/widgets/widgets/qmenu.cpp
+++ b/src/widgets/widgets/qmenu.cpp
@@ -70,22 +70,6 @@
 QT_BEGIN_NAMESPACE
 
 QMenu *QMenuPrivate::mouseDown = 0;
-QPointer<QMenu> QMenuPrivate::previousMouseMenu(Q_NULLPTR);
-static void handleEnterLeaveEvents(QPointer<QMenu> *previous_ptr, QMenu *next)
-{
-    QWidget *previous = previous_ptr->data();
-    if (previous != next) {
-        if (previous) {
-            QEvent leaveEvent(QEvent::Leave);
-            QApplication::sendEvent(previous, &leaveEvent);
-        }
-        if (next) {
-            QEvent enterEvent(QEvent::Enter);
-            QApplication::sendEvent(next, &enterEvent);
-        }
-    }
-    *previous_ptr = next;
-}
 
 /* QMenu code */
 // internal class used for the torn off popup
@@ -504,8 +488,6 @@ void QMenuPrivate::hideMenu(QMenu *menu)
     menu->d_func()->causedPopup.action = 0;
     menu->close();
     menu->d_func()->causedPopup.widget = 0;
-    if (previousMouseMenu.data() == menu)
-        handleEnterLeaveEvents(&previousMouseMenu, Q_NULLPTR);
 }
 
 void QMenuPrivate::popupAction(QAction *action, int delay, bool activateFirst)
@@ -671,10 +653,26 @@ void QMenuSloppyState::enter()
         m_parent->childEnter();
 }
 
+void QMenuSloppyState::childEnter()
+{
+    stopTimer();
+    if (m_parent)
+        m_parent->childEnter();
+}
+
+void QMenuSloppyState::leave()
+{
+    if (!m_dont_start_time_on_leave) {
+        if (m_parent)
+            m_parent->childLeave();
+        startTimerIfNotRunning();
+    }
+}
+
 void QMenuSloppyState::childLeave()
 {
     if (m_enabled && !QMenuPrivate::get(m_menu)->hasReceievedEnter) {
-        startTimer();
+        startTimerIfNotRunning();
         if (m_parent)
             m_parent->childLeave();
     }
@@ -720,8 +718,17 @@ public:
 void QMenuSloppyState::timeout()
 {
     QMenuPrivate *menu_priv = QMenuPrivate::get(m_menu);
+
+    bool reallyHasMouse = menu_priv->hasReceievedEnter;
+    if (!reallyHasMouse) {
+        // Check whether the menu really has a mouse, because only active popup
+        // menu gets the enter/leave events. Currently Cocoa is an exception.
+        const QPoint lastCursorPos = QGuiApplicationPrivate::lastCursorPosition.toPoint();
+        reallyHasMouse = m_menu->frameGeometry().contains(lastCursorPos);
+    }
+
     if (menu_priv->currentAction == m_reset_action
-            && menu_priv->hasReceievedEnter
+            && reallyHasMouse
             && (menu_priv->currentAction
                 && menu_priv->currentAction->menu() == menu_priv->activeMenu)) {
         return;
@@ -729,13 +736,13 @@ void QMenuSloppyState::timeout()
 
     ResetOnDestroy resetState(this, &m_init_guard);
 
-    if (hasParentActiveDelayTimer() || !m_menu || !m_menu->isVisible())
+    if (hasParentActiveDelayTimer() || !m_menu->isVisible())
         return;
 
     if (m_sub_menu)
         menu_priv->hideMenu(m_sub_menu);
 
-    if (menu_priv->hasReceievedEnter)
+    if (reallyHasMouse)
         menu_priv->setCurrentAction(m_reset_action,0);
     else
         menu_priv->setCurrentAction(Q_NULLPTR, 0);
@@ -1089,10 +1096,8 @@ bool QMenuPrivate::mouseEventTaken(QMouseEvent *e)
         tearoffHighlighted = 0;
     }
 
-    if (q->frameGeometry().contains(e->globalPos())) { //otherwise if the event is in our rect we want it..
-        handleEnterLeaveEvents(&previousMouseMenu, q);
-        return false;
-    }
+    if (q->frameGeometry().contains(e->globalPos()))
+        return false; //otherwise if the event is in our rect we want it..
 
     for(QWidget *caused = causedPopup.widget; caused;) {
         bool passOnEvent = false;
@@ -1108,17 +1113,16 @@ bool QMenuPrivate::mouseEventTaken(QMouseEvent *e)
             next_widget = m->d_func()->causedPopup.widget;
         }
         if (passOnEvent) {
-            handleEnterLeaveEvents(&previousMouseMenu,qobject_cast<QMenu *>(caused));
-            if(e->type() != QEvent::MouseButtonRelease || mouseDown == caused) {
-            QMouseEvent new_e(e->type(), cpos, caused->mapTo(caused->topLevelWidget(), cpos), e->screenPos(),
-                              e->button(), e->buttons(), e->modifiers(), e->source());
-            QApplication::sendEvent(caused, &new_e);
-            return true;
+            if (e->type() != QEvent::MouseButtonRelease || mouseDown == caused) {
+                QMouseEvent new_e(e->type(), cpos, caused->mapTo(caused->topLevelWidget(), cpos), e->screenPos(),
+                                  e->button(), e->buttons(), e->modifiers(), e->source());
+                QApplication::sendEvent(caused, &new_e);
+                return true;
             }
         }
         caused = next_widget;
         if (!caused)
-            handleEnterLeaveEvents(&previousMouseMenu, Q_NULLPTR);
+            sloppyState.leave(); // Start timers
     }
     return false;
 }
@@ -3169,7 +3173,6 @@ void QMenu::enterEvent(QEvent *)
     Q_D(QMenu);
     d->hasReceievedEnter = true;
     d->sloppyState.enter();
-    d->sloppyState.startTimer();
     d->motions = -1; // force us to ignore the generate mouse move in mouseMoveEvent()
 }
 
@@ -3180,7 +3183,6 @@ void QMenu::leaveEvent(QEvent *)
 {
     Q_D(QMenu);
     d->hasReceievedEnter = false;
-    d->sloppyState.leave();
     if (!d->activeMenu && d->currentAction)
         setActiveAction(0);
 }
@@ -3352,10 +3354,18 @@ void QMenu::internalDelayedPopup()
     const QRect actionRect(d->actionRect(d->currentAction));
     const QPoint rightPos(mapToGlobal(QPoint(actionRect.right() + subMenuOffset + 1, actionRect.top())));
 
-    QPoint pos(rightPos);
-
-    d->activeMenu->popup(pos);
+    d->activeMenu->popup(rightPos);
     d->sloppyState.setSubMenuPopup(actionRect, d->currentAction, d->activeMenu);
+
+#if !defined(Q_OS_DARWIN)
+    // Send the leave event to the current menu - only active popup menu gets
+    // mouse enter/leave events. Currently Cocoa is an exception, so disable
+    // it there to avoid event duplication.
+    if (underMouse()) {
+        QEvent leaveEvent(QEvent::Leave);
+        QCoreApplication::sendEvent(this, &leaveEvent);
+    }
+#endif
 }
 
 /*!
diff --git a/src/widgets/widgets/qmenu_p.h b/src/widgets/widgets/qmenu_p.h
index e717d923ae..c78abf8aed 100644
--- a/src/widgets/widgets/qmenu_p.h
+++ b/src/widgets/widgets/qmenu_p.h
@@ -122,8 +122,6 @@ public:
     void reset();
     bool enabled() const { return m_enabled; }
 
-    void setResetAction(QAction *action) { m_reset_action = action; }
-
     enum MouseEventResult {
         EventIsProcessed,
         EventShouldBePropagated,
@@ -148,22 +146,9 @@ public:
     }
 
     void enter();
+    void childEnter();
 
-    void childEnter()
-    {
-        stopTimer();
-        if (m_parent)
-            m_parent->childEnter();
-    }
-
-    void leave()
-    {
-        if (m_dont_start_time_on_leave)
-            return;
-        if (m_parent)
-            m_parent->childLeave();
-        startTimer();
-    }
+    void leave();
     void childLeave();
 
     static float slope(const QPointF &p1, const QPointF &p2)
@@ -189,8 +174,7 @@ public:
         if (!m_enabled)
             return EventShouldBePropagated;
 
-        if (!m_time.isActive())
-            startTimer();
+        startTimerIfNotRunning();
 
         if (!m_sub_menu) {
             reset();
@@ -493,7 +477,6 @@ public:
     QAction* wceCommands(uint command);
 #endif
     QPointer<QWidget> noReplayFor;
-    static QPointer<QMenu> previousMouseMenu;
 };
 
 #endif // QT_NO_MENU
diff --git a/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp b/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp
index 34a1835413..50d7b258bc 100644
--- a/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp
+++ b/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp
@@ -10358,8 +10358,11 @@ void tst_QWidget::underMouse()
     QCOMPARE(childWidget2.leaves, 0);
 
     // Mouse leaves popup and enters topLevelWidget, should cause leave for popup
-    // but no enter to topLevelWidget. Again, artificial leave event needed.
+    // but no enter to topLevelWidget.
+#ifdef Q_OS_DARWIN
+    // Artificial leave event needed for Cocoa.
     QWindowSystemInterface::handleLeaveEvent(popupWindow);
+#endif
     QTest::mouseMove(popupWindow, popupWindow->mapFromGlobal(window->mapToGlobal(inWindowPoint)));
     QApplication::processEvents();
     QVERIFY(!topLevelWidget.underMouse());