Delay initialization of QQnxRootWindow until first access.

QtWebProcess, for example, doesn't create any QWindow, so it doesn't
need any root window.

This fixes Webkit2 rendering on QNX.

Change-Id: I1d4c0dd20869798ba2bcd15f9d96e5fca4beb48e
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

src/plugins/platforms/qnx/qqnxrootwindow.cpp

@@ -57,7 +57,7 @@
 
 static const int MAGIC_ZORDER_FOR_NO_NAV = 10;
 
-QQnxRootWindow::QQnxRootWindow(QQnxScreen *screen)
+QQnxRootWindow::QQnxRootWindow(const QQnxScreen *screen)
     : m_screen(screen),
       m_window(0),
       m_windowGroupName()

src/plugins/platforms/qnx/qqnxrootwindow.h

@@ -54,7 +54,7 @@ class QQnxScreen;
 class QQnxRootWindow
 {
 public:
-    QQnxRootWindow(QQnxScreen *screen);
+    QQnxRootWindow(const QQnxScreen *screen);
     ~QQnxRootWindow();
 
     screen_window_t nativeHandle() const { return m_window; }
@@ -71,7 +71,7 @@ public:
 private:
     void createWindowGroup();
 
-    QQnxScreen *m_screen;
+    const QQnxScreen *m_screen;
     screen_window_t m_window;
     QByteArray m_windowGroupName;
 };

src/plugins/platforms/qnx/qqnxscreen.cpp

@@ -106,7 +106,6 @@ static QSize determineScreenSize(screen_display_t display, bool primaryScreen) {
 QQnxScreen::QQnxScreen(screen_context_t screenContext, screen_display_t display, bool primaryScreen)
     : m_screenContext(screenContext),
       m_display(display),
-      m_rootWindow(),
       m_primaryScreen(primaryScreen),
       m_posted(false),
       m_keyboardHeight(0),
@@ -145,10 +144,6 @@ QQnxScreen::QQnxScreen(screen_context_t screenContext, screen_display_t display,
         m_currentPhysicalSize = m_initialPhysicalSize = screenSize;
     else
         m_currentPhysicalSize = m_initialPhysicalSize = screenSize.transposed();
-
-    // We only create the root window if we are the primary display.
-    if (primaryScreen)
-        m_rootWindow = QSharedPointer<QQnxRootWindow>(new QQnxRootWindow(this));
 }
 
 QQnxScreen::~QQnxScreen()
@@ -248,8 +243,8 @@ void QQnxScreen::setRotation(int rotation)
     // Check if rotation changed
     if (m_currentRotation != rotation) {
         // Update rotation of root window
-        if (m_rootWindow)
-            m_rootWindow->setRotation(rotation);
+        if (rootWindow())
+            rootWindow()->setRotation(rotation);
 
         const QRect previousScreenGeometry = geometry();
 
@@ -265,16 +260,16 @@ void QQnxScreen::setRotation(int rotation)
         // Resize root window if we've rotated 90 or 270 from previous orientation
         if (isOrthogonal(m_currentRotation, rotation)) {
             qScreenDebug() << Q_FUNC_INFO << "resize, size =" << m_currentGeometry.size();
-            if (m_rootWindow)
-                m_rootWindow->resize(m_currentGeometry.size());
+            if (rootWindow())
+                rootWindow()->resize(m_currentGeometry.size());
 
             if (m_primaryScreen)
                 resizeWindows(previousScreenGeometry);
         } else {
             // TODO: Find one global place to flush display updates
             // Force immediate display update if no geometry changes required
-            if (m_rootWindow)
-                m_rootWindow->flush();
+            if (rootWindow())
+                rootWindow()->flush();
         }
 
         // Save new rotation
@@ -491,8 +486,8 @@ void QQnxScreen::onWindowPost(QQnxWindow *window)
     // post app window (so navigator will show it) after first child window
     // has posted; this only needs to happen once as the app window's content
     // never changes
-    if (!m_posted && m_rootWindow) {
-        m_rootWindow->post();
+    if (!m_posted && rootWindow()) {
+        rootWindow()->post();
         m_posted = true;
     }
 }
@@ -573,4 +568,13 @@ void QQnxScreen::deactivateWindowGroup(const QByteArray &id)
     QWindowSystemInterface::handleWindowActivated(0);
 }
 
+QSharedPointer<QQnxRootWindow> QQnxScreen::rootWindow() const
+{
+    // We only create the root window if we are the primary display.
+    if (m_primaryScreen && !m_rootWindow)
+        m_rootWindow = QSharedPointer<QQnxRootWindow>(new QQnxRootWindow(this));
+
+    return m_rootWindow;
+}
+
 QT_END_NAMESPACE

src/plugins/platforms/qnx/qqnxscreen.h

@@ -80,7 +80,7 @@ public:
     int nativeFormat() const { return (depth() == 32) ? SCREEN_FORMAT_RGBA8888 : SCREEN_FORMAT_RGB565; }
     screen_display_t nativeDisplay() const { return m_display; }
     screen_context_t nativeContext() const { return m_screenContext; }
-    const char *windowGroupName() const { return m_rootWindow->groupName().constData(); }
+    const char *windowGroupName() const { return rootWindow()->groupName().constData(); }
 
     QQnxWindow *findWindow(screen_window_t windowHandle);
 
@@ -93,7 +93,7 @@ public:
 
     void onWindowPost(QQnxWindow *window);
 
-    QSharedPointer<QQnxRootWindow> rootWindow() const { return m_rootWindow; }
+    QSharedPointer<QQnxRootWindow> rootWindow() const;
 
 public Q_SLOTS:
     void setRotation(int rotation);
@@ -114,8 +114,8 @@ private:
 
     screen_context_t m_screenContext;
     screen_display_t m_display;
-    QSharedPointer<QQnxRootWindow> m_rootWindow;
-    bool m_primaryScreen;
+    mutable QSharedPointer<QQnxRootWindow> m_rootWindow;
+    const bool m_primaryScreen;
     bool m_posted;
 
     int m_initialRotation;