Redirect keyboard/mouse grab to the widget parent window.

Use the native parent's window if the widget in question does not
have one. This should be in line with Qt 4.8 using effectiveWinId().

Remove redundant code in grabMouse(QCursor).

Change-Id: Id6ab192e739221fe89f865f4d2f7a6d4671a190b
Reviewed-by: Qt Doc Bot <qt_docbot@qt-project.org>
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@digia.com>
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>

diff --git a/src/widgets/kernel/qwidget_qpa.cpp b/src/widgets/kernel/qwidget_qpa.cpp
index 7b649f6..7c84c7f 100644 (file)
--- a/src/widgets/kernel/qwidget_qpa.cpp
+++ b/src/widgets/kernel/qwidget_qpa.cpp
@@ -362,13 +362,22 @@ QWidget *qt_pressGrab = 0;
 QWidget *qt_mouseGrb = 0;
 static QWidget *keyboardGrb = 0;
 
+static inline QWindow *grabberWindow(const QWidget *w)
+{
+    QWindow *window = w->windowHandle();
+    if (!window)
+        if (const QWidget *nativeParent = w->nativeParentWidget())
+            window = nativeParent->windowHandle();
+    return window;
+}
+
 void QWidget::grabMouse()
 {
     if (qt_mouseGrb)
         qt_mouseGrb->releaseMouse();
 
-    if (windowHandle())
-        windowHandle()->setMouseGrabEnabled(true);
+    if (QWindow *window = grabberWindow(this))
+        window->setMouseGrabEnabled(true);
 
     qt_mouseGrb = this;
     qt_pressGrab = 0;
@@ -378,15 +387,7 @@ void QWidget::grabMouse()
 void QWidget::grabMouse(const QCursor &cursor)
 {
     Q_UNUSED(cursor);
-
-    if (qt_mouseGrb)
-        qt_mouseGrb->releaseMouse();
-
-    if (windowHandle())
-        windowHandle()->setMouseGrabEnabled(true);
-
-    qt_mouseGrb = this;
-    qt_pressGrab = 0;
+    grabMouse();
 }
 #endif
 
@@ -395,14 +396,15 @@ bool QWidgetPrivate::stealMouseGrab(bool grab)
     // This is like a combination of grab/releaseMouse() but with error checking
     // and it has no effect on the result of mouseGrabber().
     Q_Q(QWidget);
-    return q->windowHandle() ? q->windowHandle()->setMouseGrabEnabled(grab) : false;
+    QWindow *window = grabberWindow(q);
+    return window ? window->setMouseGrabEnabled(grab) : false;
 }
 
 void QWidget::releaseMouse()
 {
     if (qt_mouseGrb == this) {
-        if (windowHandle())
-            windowHandle()->setMouseGrabEnabled(false);
+        if (QWindow *window = grabberWindow(this))
+            window->setMouseGrabEnabled(false);
         qt_mouseGrb = 0;
     }
 }
@@ -411,8 +413,8 @@ void QWidget::grabKeyboard()
 {
     if (keyboardGrb)
         keyboardGrb->releaseKeyboard();
-    if (windowHandle())
-        windowHandle()->setKeyboardGrabEnabled(true);
+    if (QWindow *window = grabberWindow(this))
+        window->setKeyboardGrabEnabled(true);
     keyboardGrb = this;
 }
 
@@ -421,14 +423,15 @@ bool QWidgetPrivate::stealKeyboardGrab(bool grab)
     // This is like a combination of grab/releaseKeyboard() but with error
     // checking and it has no effect on the result of keyboardGrabber().
     Q_Q(QWidget);
-    return q->windowHandle() ? q->windowHandle()->setKeyboardGrabEnabled(grab) : false;
+    QWindow *window = grabberWindow(q);
+    return window ? window->setKeyboardGrabEnabled(grab) : false;
 }
 
 void QWidget::releaseKeyboard()
 {
     if (keyboardGrb == this) {
-        if (windowHandle())
-            windowHandle()->setKeyboardGrabEnabled(false);
+        if (QWindow *window = grabberWindow(this))
+            window->setKeyboardGrabEnabled(false);
         keyboardGrb = 0;
     }
 }

diff --git a/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp b/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp
index 322f978..c457d60 100644 (file)
--- a/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp
+++ b/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp
@@ -383,6 +383,7 @@ private slots:
 
     void nativeChildFocus();
     void grab();
+    void grabMouse();
 
     void touchEventSynthesizedMouseEvent();
 
@@ -9333,6 +9334,75 @@ void tst_QWidget::grab()
     }
 }
 
+/* grabMouse() tests whether mouse grab for a widget without window handle works.
+ * It creates a top level widget with another nested widget inside. The inner widget grabs
+ * the mouse and a series of mouse presses moving over the top level's window is simulated.
+ * Only the inner widget should receive events. */
+
+static inline QString mouseEventLogEntry(const QString &objectName, QEvent::Type t, const QPoint &p, Qt::MouseButtons b)
+{
+    QString result;
+    QDebug(&result).nospace() << objectName << " Mouse event " << t << " at " << p << " buttons " << b;
+    return result;
+}
+
+class GrabLoggerWidget : public QWidget {
+public:
+    explicit GrabLoggerWidget(QStringList *log, QWidget *parent = 0)  : QWidget(parent), m_log(log) {}
+
+protected:
+    bool event(QEvent *e)
+    {
+        switch (e->type()) {
+        case QEvent::MouseButtonPress:
+        case QEvent::MouseMove:
+        case QEvent::MouseButtonRelease: {
+            QMouseEvent *me = static_cast<QMouseEvent *>(e);
+            m_log->push_back(mouseEventLogEntry(objectName(), me->type(), me->pos(), me->buttons()));
+            me->accept();
+            return true;
+        }
+        default:
+            break;
+        }
+        return QWidget::event(e);
+    }
+private:
+    QStringList *m_log;
+};
+
+void tst_QWidget::grabMouse()
+{
+    QStringList log;
+    GrabLoggerWidget w(&log);
+    w.setObjectName(QLatin1String("tst_qwidget_grabMouse"));
+    w.setWindowTitle(w.objectName());
+    QLayout *layout = new QVBoxLayout(&w);
+    layout->setMargin(50);
+    GrabLoggerWidget *grabber = new GrabLoggerWidget(&log, &w);
+    const QString grabberObjectName = QLatin1String("tst_qwidget_grabMouse_grabber");
+    grabber->setObjectName(grabberObjectName);
+    grabber->setMinimumSize(100, 100);
+    layout->addWidget(grabber);
+    w.show();
+    qApp->setActiveWindow(&w);
+    QVERIFY(QTest::qWaitForWindowActive(&w));
+
+    QStringList expectedLog;
+    grabber->grabMouse();
+    QPoint mousePos = QPoint(w.width() / 2, 10);
+    const int step = w.height() / 5;
+    for ( ; mousePos.y() < w.height() ; mousePos.ry() += step) {
+        QTest::mouseClick(w.windowHandle(), Qt::LeftButton, 0, mousePos);
+        // Events should go to the grabber child using its coordinates.
+        const QPoint expectedPos = grabber->mapFromParent(mousePos);
+        expectedLog.push_back(mouseEventLogEntry(grabberObjectName, QEvent::MouseButtonPress, expectedPos, Qt::LeftButton));
+        expectedLog.push_back(mouseEventLogEntry(grabberObjectName, QEvent::MouseButtonRelease, expectedPos, Qt::NoButton));
+    }
+    grabber->releaseMouse();
+    QCOMPARE(log, expectedLog);
+}
+
 class TouchMouseWidget : public QWidget {
 public:
     explicit TouchMouseWidget(QWidget *parent = 0)