Implement alien widgets on Mac/Cocoa.

This commit makes alien widgets opt in on a
per-widget basis on Mac, set the Qt::WA_NativeWindow
flag when creating the widget to enable. Setting
this flag on widgets that have native child or sibling
NSViews is not supported.

The main use case for alien widgets on Mac is to
improve performance for applications that have complex
user interfaces. Qt can handle thousands of widgets
per window, while Cocoa is designed to use a smaller
number of NSViews in combination with NSCells and
custom control implementations. This commit moves
us in the direction of having a few main NSViews with
"leaf" qwidgets implemented as a custom control.

1 files changed, 37 insertions, 6 deletions

diff --git a/src/gui/kernel/qwidget.cpp b/src/gui/kernel/qwidget.cpp
index 2f6ec6b..b19d541 100644
--- a/src/gui/kernel/qwidget.cpp
+++ b/src/gui/kernel/qwidget.cpp
@@ -205,6 +205,7 @@ QWidgetPrivate::QWidgetPrivate(int version)
       , nativeGesturePanEnabled(0)
 #elif defined(Q_WS_MAC)
       , needWindowChange(0)
+      , hasAlienChildren(0)
       , window_event(0)
       , qd_hd(0)
 #endif
@@ -1168,6 +1169,10 @@ void QWidgetPrivate::init(QWidget *parentWidget, Qt::WindowFlags f)
     if (f & Qt::MSWindowsOwnDC)
         q->setAttribute(Qt::WA_NativeWindow);
 
+#ifdef Q_WS_MAC
+    q->setAttribute(Qt::WA_NativeWindow);
+#endif
+
     q->setAttribute(Qt::WA_QuitOnClose); // might be cleared in adjustQuitOnCloseAttribute()
     adjustQuitOnCloseAttribute();
 
@@ -1263,6 +1268,10 @@ void QWidget::create(WId window, bool initializeWindow, bool destroyOldWindow)
     }
 
     if (QWidget *parent = parentWidget()) {
+#ifdef Q_WS_MAC
+        if (testAttribute(Qt::WA_NativeWindow) == false)
+            parent->d_func()->hasAlienChildren = true;
+#endif
         if (type & Qt::Window) {
             if (!parent->testAttribute(Qt::WA_WState_Created))
                 parent->createWinId();
@@ -1433,7 +1442,7 @@ QWidget::~QWidget()
         }
     }
 
-#if defined(Q_WS_WIN) || defined(Q_WS_X11) || defined (Q_WS_QWS)
+#if defined(Q_WS_WIN) || defined(Q_WS_X11) || defined (Q_WS_QWS) || defined(Q_WS_MAC)
     else if (!internalWinId() && isVisible()) {
         qApp->d_func()->sendSyntheticEnterLeave(this);
 #ifdef Q_WS_QWS
@@ -2306,6 +2315,9 @@ QWidget *QWidget::find(WId id)
 WId QWidget::winId() const
 {
     if (!testAttribute(Qt::WA_WState_Created) || !internalWinId()) {
+#ifdef ALIEN_DEBUG
+        qDebug() << "QWidget::winId: creating native window for" << this;
+#endif
         QWidget *that = const_cast<QWidget*>(this);
         that->setAttribute(Qt::WA_NativeWindow);
         that->d_func()->createWinId();
@@ -2318,6 +2330,10 @@ WId QWidget::winId() const
 void QWidgetPrivate::createWinId(WId winid)
 {
     Q_Q(QWidget);
+
+#ifdef ALIEN_DEBUG
+    qDebug() << "QWidgetPrivate::createWinId for" << q << winid;
+#endif
     const bool forceNativeWindow = q->testAttribute(Qt::WA_NativeWindow);
     if (!q->testAttribute(Qt::WA_WState_Created) || (forceNativeWindow && !q->internalWinId())) {
         if (!q->isWindow()) {
@@ -2360,6 +2376,9 @@ Ensures that the widget has a window system identifier, i.e. that it is known to
 void QWidget::createWinId()
 {
     Q_D(QWidget);
+#ifdef ALIEN_DEBUG
+    qDebug()  << "QWidget::createWinId" << this;
+#endif
 //    qWarning("QWidget::createWinId is obsolete, please fix your code.");
     d->createWinId();
 }
@@ -5249,7 +5268,15 @@ void QWidgetPrivate::drawWidget(QPaintDevice *pdev, const QRegion &rgn, const QP
             QPaintEngine *paintEngine = pdev->paintEngine();
             if (paintEngine) {
                 setRedirected(pdev, -offset);
+#ifdef Q_WS_MAC
+                // (Alien support) Special case for Mac when redirecting: If the paint device
+                // is of the Widget type we need to set WA_WState_InPaintEvent since painting
+                // outside the paint event is not supported on QWidgets. The attributeis
+                // restored further down.
+                if (pdev->devType() == QInternal::Widget)
+                    static_cast<QWidget *>(pdev)->setAttribute(Qt::WA_WState_InPaintEvent);
 
+#endif
                 if (sharedPainter)
                     paintEngine->d_func()->systemClip = toBePainted;
                 else
@@ -5290,6 +5317,10 @@ void QWidgetPrivate::drawWidget(QPaintDevice *pdev, const QRegion &rgn, const QP
 
             //restore
             if (paintEngine) {
+#ifdef Q_WS_MAC
+                if (pdev->devType() == QInternal::Widget)
+                    static_cast<QWidget *>(pdev)->setAttribute(Qt::WA_WState_InPaintEvent, false);
+#endif
                 restoreRedirected();
                 if (!sharedPainter)
                     paintEngine->d_func()->systemRect = QRect();
@@ -7322,7 +7353,7 @@ void QWidgetPrivate::hide_helper()
     // next bit tries to move the focus if the focus widget is now
     // hidden.
     if (wasVisible) {
-#if defined(Q_WS_WIN) || defined(Q_WS_X11) || defined (Q_WS_QWS)
+#if defined(Q_WS_WIN) || defined(Q_WS_X11) || defined (Q_WS_QWS) || defined(Q_WS_MAC)
         qApp->d_func()->sendSyntheticEnterLeave(q);
 #endif
 
@@ -7454,7 +7485,7 @@ void QWidget::setVisible(bool visible)
 
             d->show_helper();
 
-#if defined(Q_WS_WIN) || defined(Q_WS_X11) || defined (Q_WS_QWS)
+#if defined(Q_WS_WIN) || defined(Q_WS_X11) || defined (Q_WS_QWS) || defined(Q_WS_MAC)
             qApp->d_func()->sendSyntheticEnterLeave(this);
 #endif
         }
@@ -7569,7 +7600,7 @@ void QWidgetPrivate::hideChildren(bool spontaneous)
                 widget->d_func()->hide_sys();
             }
         }
-#if defined(Q_WS_WIN) || defined(Q_WS_X11) || defined (Q_WS_QWS)
+#if defined(Q_WS_WIN) || defined(Q_WS_X11) || defined (Q_WS_QWS) || defined(Q_WS_MAC)
         qApp->d_func()->sendSyntheticEnterLeave(widget);
 #endif
 #ifndef QT_NO_ACCESSIBILITY
@@ -9787,7 +9818,7 @@ void QWidget::setParent(QWidget *parent, Qt::WindowFlags f)
         desktopWidget = parent;
     bool newParent = (parent != parentWidget()) || !wasCreated || desktopWidget;
 
-#if defined(Q_WS_X11) || defined(Q_WS_WIN)
+#if defined(Q_WS_X11) || defined(Q_WS_WIN) || defined(Q_WS_MAC)
     if (newParent && parent && !desktopWidget) {
         if (testAttribute(Qt::WA_NativeWindow) && !qApp->testAttribute(Qt::AA_DontCreateNativeWidgetSiblings))
             parent->d_func()->enforceNativeChildren();
@@ -10433,7 +10464,7 @@ void QWidget::setAttribute(Qt::WidgetAttribute attribute, bool on)
     }
     case Qt::WA_PaintOnScreen:
         d->updateIsOpaque();
-#if defined(Q_WS_WIN) || defined(Q_WS_X11)
+#if defined(Q_WS_WIN) || defined(Q_WS_X11) || defined(Q_WS_MAC)
         // Recreate the widget if it's already created as an alien widget and
         // WA_PaintOnScreen is enabled. Paint on screen widgets must have win id.
         // So must their children.