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, 39 insertions, 11 deletions

diff --git a/src/gui/kernel/qwidget_mac.mm b/src/gui/kernel/qwidget_mac.mm
index dcb87fc..6d8c97b 100644
--- a/src/gui/kernel/qwidget_mac.mm
+++ b/src/gui/kernel/qwidget_mac.mm
@@ -459,7 +459,13 @@ static bool qt_isGenuineQWidget(OSViewRef ref)
 
 bool qt_isGenuineQWidget(const QWidget *window)
 {
-    return window && qt_isGenuineQWidget(OSViewRef(window->winId()));
+    if (!window)
+        return false;
+
+    if (!window->internalWinId())
+        return true;  //alien
+
+    return qt_isGenuineQWidget(OSViewRef(window->internalWinId()));
 }
 
 Q_GUI_EXPORT OSWindowRef qt_mac_window_for(const QWidget *w)
@@ -2608,7 +2614,16 @@ void QWidgetPrivate::create_sys(WId window, bool initializeWindow, bool destroyO
         }
     } else {
         data.fstrut_dirty = false; // non-toplevel widgets don't have a frame, so no need to update the strut
-        if(OSViewRef osview = qt_mac_create_widget(q, this, qt_mac_nativeview_for(parentWidget))) {
+
+#ifdef QT_MAC_USE_COCOA
+        if (q->testAttribute(Qt::WA_NativeWindow) == false ||
+            q->internalWinId() != 0) {
+#ifdef ALIEN_DEBUG
+            qDebug() << "Skipping native widget creation for" << this;
+#endif
+        } else
+#endif
+        if (OSViewRef osview = qt_mac_create_widget(q, this, qt_mac_nativeview_for(parentWidget))) {
 #ifndef QT_MAC_USE_COCOA
             HIRect bounds = CGRectMake(data.crect.x(), data.crect.y(), data.crect.width(), data.crect.height());
             HIViewSetFrame(osview, &bounds);
@@ -2869,9 +2884,12 @@ void QWidgetPrivate::setParent_sys(QWidget *parent, Qt::WindowFlags f)
     q->setAttribute(Qt::WA_WState_Visible, false);
     q->setAttribute(Qt::WA_WState_Hidden, false);
     adjustFlags(data.window_flags, q);
-    // keep compatibility with previous versions, we need to preserve the created state
-    // (but we recreate the winId for the widget being reparented, again for compatibility)
-    if (wasCreated || (!q->isWindow() && parent->testAttribute(Qt::WA_WState_Created))) {
+    // keep compatibility with previous versions, we need to preserve the created state.
+    // (but we recreate the winId for the widget being reparented, again for compatibility,
+    // unless this is an alien widget. )
+    const bool nonWindowWithCreatedParent = !q->isWindow() && parent->testAttribute(Qt::WA_WState_Created);
+    const bool nativeWidget = q->internalWinId() != 0;
+    if (wasCreated || nativeWidget && nonWindowWithCreatedParent) {
         createWinId();
         if (q->isWindow()) {
 #ifndef QT_MAC_USE_COCOA
@@ -2955,7 +2973,7 @@ void QWidgetPrivate::setParent_sys(QWidget *parent, Qt::WindowFlags f)
 QPoint QWidget::mapToGlobal(const QPoint &pos) const
 {
     Q_D(const QWidget);
-    if (!testAttribute(Qt::WA_WState_Created)) {
+    if (!testAttribute(Qt::WA_WState_Created) || !internalWinId()) {
         QPoint p = pos + data->crect.topLeft();
         return isWindow() ?  p : parentWidget()->mapToGlobal(p);
     }
@@ -2982,7 +3000,7 @@ QPoint QWidget::mapToGlobal(const QPoint &pos) const
 QPoint QWidget::mapFromGlobal(const QPoint &pos) const
 {
     Q_D(const QWidget);
-    if (!testAttribute(Qt::WA_WState_Created)) {
+    if (!testAttribute(Qt::WA_WState_Created) || !internalWinId()) {
         QPoint p = isWindow() ?  pos : parentWidget()->mapFromGlobal(pos);
         return p - data->crect.topLeft();
     }
@@ -3320,10 +3338,20 @@ void QWidgetPrivate::update_sys(const QRegion &rgn)
     }
 #else
     // Cocoa doesn't do regions, it seems more efficient to just update the bounding rect instead of a potential number of message passes for each rect.
-    const QRect &boundingRect = rgn.boundingRect();
-    [qt_mac_nativeview_for(q) setNeedsDisplayInRect:NSMakeRect(boundingRect.x(),
-                                                            boundingRect.y(), boundingRect.width(),
-                                                            boundingRect.height())];
+    const QRect & boundingRect = rgn.boundingRect();
+
+    // Alien support: get the first native ancestor widget (will be q itself in the non-alien case),
+    // map the coordinates from q space to NSView space and invalidate the rect.
+    QWidget *nativeParent = q->internalWinId() ? q : q->nativeParentWidget();
+    if (nativeParent == 0)
+            return;
+    const QRect nativeBoundingRect = QRect(
+            QPoint(q->mapTo(nativeParent, boundingRect.topLeft())),
+            QSize(boundingRect.size()));
+
+    [qt_mac_nativeview_for(nativeParent) setNeedsDisplayInRect:NSMakeRect(nativeBoundingRect.x(),
+                                                            nativeBoundingRect.y(), nativeBoundingRect.width(),
+                                                            nativeBoundingRect.height())];
 #endif
 }