Remove scene window traces in scene items

This further decouples scene items from scene windows. The SurfaceItem
still needs to access the underlying window, I would like to re-iterate
over that later.

With this change, it will be possible to introduce WindowItem factory
function in the Toplevel class.

src/decorationitem.cpp

@@ -103,16 +103,18 @@ void DecorationRenderer::renderToPainter(QPainter *painter, const QRect &rect)
     client()->decoration()->paint(painter, rect);
 }
 
-DecorationItem::DecorationItem(KDecoration2::Decoration *decoration, Scene::Window *window, Item *parent)
-    : Item(window, parent)
+DecorationItem::DecorationItem(KDecoration2::Decoration *decoration, AbstractClient *window, Item *parent)
+    : Item(parent)
+    , m_window(window)
 {
-    AbstractClient *client = qobject_cast<AbstractClient *>(window->window());
-    m_renderer.reset(Compositor::self()->scene()->createDecorationRenderer(client->decoratedClient()));
+    m_renderer.reset(Compositor::self()->scene()->createDecorationRenderer(window->decoratedClient()));
 
-    connect(client, &Toplevel::frameGeometryChanged,
+    connect(window, &Toplevel::frameGeometryChanged,
             this, &DecorationItem::handleFrameGeometryChanged);
+    connect(window, &Toplevel::windowClosed,
+            this, &DecorationItem::handleWindowClosed);
 
-    connect(client, &Toplevel::screenScaleChanged,
+    connect(window, &Toplevel::screenScaleChanged,
             this, &DecorationItem::discardQuads);
     connect(decoration, &KDecoration2::Decoration::bordersChanged,
             this, &DecorationItem::discardQuads);
@@ -120,10 +122,7 @@ DecorationItem::DecorationItem(KDecoration2::Decoration *decoration, Scene::Wind
     connect(renderer(), &DecorationRenderer::damaged,
             this, &DecorationItem::scheduleRepaint);
 
-    // If the decoration is about to be destroyed, render the decoration for the last time.
-    connect(client, &Toplevel::markedAsZombie, this, &DecorationItem::preprocess);
-
-    setSize(client->size());
+    setSize(window->size());
 }
 
 void DecorationItem::preprocess()
@@ -137,7 +136,16 @@ void DecorationItem::preprocess()
 
 void DecorationItem::handleFrameGeometryChanged()
 {
-    setSize(window()->size());
+    setSize(m_window->size());
+}
+
+void DecorationItem::handleWindowClosed(Toplevel *original, Deleted *deleted)
+{
+    Q_UNUSED(original)
+    m_window = deleted;
+
+    // If the decoration is about to be destroyed, render the decoration for the last time.
+    preprocess();
 }
 
 DecorationRenderer *DecorationItem::renderer() const
@@ -147,20 +155,19 @@ DecorationRenderer *DecorationItem::renderer() const
 
 WindowQuadList DecorationItem::buildQuads() const
 {
-    const Toplevel *toplevel = window()->window();
-    if (toplevel->frameMargins().isNull()) {
+    if (m_window->frameMargins().isNull()) {
         return WindowQuadList();
     }
 
     QRect rects[4];
 
-    if (const AbstractClient *client = qobject_cast<const AbstractClient *>(toplevel)) {
+    if (const AbstractClient *client = qobject_cast<const AbstractClient *>(m_window)) {
         client->layoutDecorationRects(rects[0], rects[1], rects[2], rects[3]);
-    } else if (const Deleted *deleted = qobject_cast<const Deleted *>(toplevel)) {
+    } else if (const Deleted *deleted = qobject_cast<const Deleted *>(m_window)) {
         deleted->layoutDecorationRects(rects[0], rects[1], rects[2], rects[3]);
     }
 
-    const qreal textureScale = toplevel->screenScale();
+    const qreal textureScale = m_window->screenScale();
     const int padding = 1;
 
     const QPoint topSpritePosition(padding, padding);

src/decorationitem.h

@@ -16,6 +16,10 @@ class Decoration;
 namespace KWin
 {
 
+class AbstractClient;
+class Deleted;
+class Toplevel;
+
 namespace Decoration
 {
 class DecoratedClientImpl;
@@ -65,18 +69,20 @@ class KWIN_EXPORT DecorationItem : public Item
     Q_OBJECT
 
 public:
-    explicit DecorationItem(KDecoration2::Decoration *decoration, Scene::Window *window, Item *parent = nullptr);
+    explicit DecorationItem(KDecoration2::Decoration *decoration, AbstractClient *window, Item *parent = nullptr);
 
     DecorationRenderer *renderer() const;
 
 private Q_SLOTS:
     void handleFrameGeometryChanged();
+    void handleWindowClosed(Toplevel *original, Deleted *deleted);
 
 protected:
     void preprocess() override;
     WindowQuadList buildQuads() const override;
 
 private:
+    Toplevel *m_window;
     QPointer<KDecoration2::Decoration> m_decoration;
     QScopedPointer<DecorationRenderer> m_renderer;
 };

src/item.cpp

@@ -11,12 +11,12 @@
 #include "platform.h"
 #include "renderloop.h"
 #include "screens.h"
+#include "utils.h"
 
 namespace KWin
 {
 
-Item::Item(Scene::Window *window, Item *parent)
-    : m_window(window)
+Item::Item(Item *parent)
 {
     setParentItem(parent);
 
@@ -103,11 +103,6 @@ QList<Item *> Item::childItems() const
     return m_childItems;
 }
 
-Scene::Window *Item::window() const
-{
-    return m_window;
-}
-
 QPoint Item::position() const
 {
     return m_position;

src/item.h

@@ -6,7 +6,11 @@
 
 #pragma once
 
-#include "scene.h"
+#include "kwinglobals.h"
+#include "kwineffects.h"
+
+#include <QMatrix4x4>
+#include <QObject>
 
 #include <optional>
 
@@ -21,7 +25,7 @@ class KWIN_EXPORT Item : public QObject
     Q_OBJECT
 
 public:
-    explicit Item(Scene::Window *window, Item *parent = nullptr);
+    explicit Item(Item *parent = nullptr);
     ~Item() override;
 
     QPoint position() const;
@@ -51,7 +55,6 @@ public:
     QList<Item *> childItems() const;
     QList<Item *> sortedChildItems() const;
 
-    Scene::Window *window() const;
     QPoint rootPosition() const;
 
     QMatrix4x4 transform() const;
@@ -119,7 +122,6 @@ private:
     bool computeEffectiveVisibility() const;
     void updateEffectiveVisibility();
 
-    Scene::Window *m_window;
     QPointer<Item> m_parentItem;
     QList<Item *> m_childItems;
     QMatrix4x4 m_transform;

src/platformsupport/scenes/opengl/basiceglsurfacetexture_wayland.cpp

@@ -10,6 +10,7 @@
 #include "kwingltexture.h"
 #include "logging.h"
 #include "surfaceitem_wayland.h"
+#include "utils.h"
 
 #include <KWaylandServer/drmclientbuffer.h>
 #include <KWaylandServer/linuxdmabufv1clientbuffer.h>

src/platformsupport/scenes/opengl/platformopenglsurfacetexture_internal.h

@@ -11,6 +11,8 @@
 namespace KWin
 {
 
+class SurfacePixmapInternal;
+
 class KWIN_EXPORT PlatformOpenGLSurfaceTextureInternal : public PlatformOpenGLSurfaceTexture
 {
 public:

src/platformsupport/scenes/opengl/platformopenglsurfacetexture_wayland.h

@@ -11,6 +11,8 @@
 namespace KWin
 {
 
+class SurfacePixmapWayland;
+
 class KWIN_EXPORT PlatformOpenGLSurfaceTextureWayland : public PlatformOpenGLSurfaceTexture
 {
 public:

src/platformsupport/scenes/opengl/platformopenglsurfacetexture_x11.h

@@ -11,6 +11,8 @@
 namespace KWin
 {
 
+class SurfacePixmapX11;
+
 class KWIN_EXPORT PlatformOpenGLSurfaceTextureX11 : public PlatformOpenGLSurfaceTexture
 {
 public:

src/platformsupport/scenes/qpainter/platformqpaintersurfacetexture_internal.h

@@ -11,6 +11,8 @@
 namespace KWin
 {
 
+class SurfacePixmapInternal;
+
 class KWIN_EXPORT PlatformQPainterSurfaceTextureInternal : public PlatformQPainterSurfaceTexture
 {
 public:

src/platformsupport/scenes/qpainter/platformqpaintersurfacetexture_wayland.cpp

@@ -6,6 +6,7 @@
 
 #include "platformqpaintersurfacetexture_wayland.h"
 #include "surfaceitem_wayland.h"
+#include "utils.h"
 
 #include <KWaylandServer/shmclientbuffer.h>
 #include <KWaylandServer/surface_interface.h>

src/platformsupport/scenes/qpainter/platformqpaintersurfacetexture_wayland.h

@@ -11,6 +11,8 @@
 namespace KWin
 {
 
+class SurfacePixmapWayland;
+
 class KWIN_EXPORT PlatformQPainterSurfaceTextureWayland : public PlatformQPainterSurfaceTexture
 {
 public:

src/plugins/platforms/x11/standalone/eglbackend.h

@@ -8,6 +8,7 @@
 
 #include "eglonxbackend.h"
 #include "platformopenglsurfacetexture_x11.h"
+#include "utils.h"
 
 #include <kwingltexture.h>
 #include <kwingltexture_p.h>

src/plugins/platforms/x11/standalone/glxbackend.h

@@ -11,6 +11,7 @@
 #include "openglbackend.h"
 #include "platformopenglsurfacetexture_x11.h"
 #include "x11eventfilter.h"
+#include "utils.h"
 
 #include <xcb/glx.h>
 #include <epoxy/glx.h>

src/scene.cpp

@@ -598,11 +598,11 @@ Scene::Window::Window(Toplevel *client, QObject *parent)
     , disable_painting(0)
 {
     if (qobject_cast<WaylandClient *>(client)) {
-        m_windowItem.reset(new WindowItemWayland(this));
+        m_windowItem.reset(new WindowItemWayland(toplevel));
     } else if (qobject_cast<X11Client *>(client) || qobject_cast<Unmanaged *>(client)) {
-        m_windowItem.reset(new WindowItemX11(this));
+        m_windowItem.reset(new WindowItemX11(toplevel));
     } else if (qobject_cast<InternalClient *>(client)) {
-        m_windowItem.reset(new WindowItemInternal(this));
+        m_windowItem.reset(new WindowItemInternal(toplevel));
     } else {
         Q_UNREACHABLE();
     }

src/shadowitem.cpp

@@ -5,15 +5,19 @@
 */
 
 #include "shadowitem.h"
+#include "deleted.h"
 #include "shadow.h"
 
 namespace KWin
 {
 
-ShadowItem::ShadowItem(Shadow *shadow, Scene::Window *window, Item *parent)
-    : Item(window, parent)
+ShadowItem::ShadowItem(Shadow *shadow, Toplevel *window, Item *parent)
+    : Item(parent)
+    , m_window(window)
     , m_shadow(shadow)
 {
+    connect(window, &Toplevel::windowClosed, this, &ShadowItem::handleWindowClosed);
+
     connect(shadow, &Shadow::offsetChanged, this, &ShadowItem::updateGeometry);
     connect(shadow, &Shadow::rectChanged, this, &ShadowItem::updateGeometry);
     connect(shadow, &Shadow::textureChanged, this, &ShadowItem::handleTextureChanged);
@@ -46,6 +50,12 @@ void ShadowItem::handleTextureChanged()
     discardQuads();
 }
 
+void ShadowItem::handleWindowClosed(Toplevel *original, Deleted *deleted)
+{
+    Q_UNUSED(original)
+    m_window = deleted;
+}
+
 static inline void distributeHorizontally(QRectF &leftRect, QRectF &rightRect)
 {
     if (leftRect.right() > rightRect.left()) {
@@ -70,10 +80,8 @@ static inline void distributeVertically(QRectF &topRect, QRectF &bottomRect)
 
 WindowQuadList ShadowItem::buildQuads() const
 {
-    const Toplevel *toplevel = window()->window();
-
     // Do not draw shadows if window width or window height is less than 5 px. 5 is an arbitrary choice.
-    if (!toplevel->wantsShadowToBeRendered() || toplevel->width() < 5 || toplevel->height() < 5) {
+    if (!m_window->wantsShadowToBeRendered() || m_window->width() < 5 || m_window->height() < 5) {
         return WindowQuadList();
     }
 

src/shadowitem.h

@@ -11,6 +11,10 @@
 namespace KWin
 {
 
+class Deleted;
+class Shadow;
+class Toplevel;
+
 /**
  * The ShadowItem class represents a nine-tile patch server-side drop-shadow.
  */
@@ -19,7 +23,7 @@ class KWIN_EXPORT ShadowItem : public Item
     Q_OBJECT
 
 public:
-    explicit ShadowItem(Shadow *shadow, Scene::Window *window, Item *parent = nullptr);
+    explicit ShadowItem(Shadow *shadow, Toplevel *window, Item *parent = nullptr);
     ~ShadowItem() override;
 
     Shadow *shadow() const;
@@ -30,8 +34,10 @@ protected:
 private Q_SLOTS:
     void handleTextureChanged();
     void updateGeometry();
+    void handleWindowClosed(Toplevel *original, Deleted *deleted);
 
 private:
+    Toplevel *m_window;
     QScopedPointer<Shadow> m_shadow;
 };
 

src/surfaceitem.cpp

@@ -5,13 +5,27 @@
 */
 
 #include "surfaceitem.h"
+#include "deleted.h"
 
 namespace KWin
 {
 
-SurfaceItem::SurfaceItem(Scene::Window *window, Item *parent)
-    : Item(window, parent)
+SurfaceItem::SurfaceItem(Toplevel *window, Item *parent)
+    : Item(parent)
+    , m_window(window)
 {
+    connect(window, &Toplevel::windowClosed, this, &SurfaceItem::handleWindowClosed);
+}
+
+Toplevel *SurfaceItem::window() const
+{
+    return m_window;
+}
+
+void SurfaceItem::handleWindowClosed(Toplevel *original, Deleted *deleted)
+{
+    Q_UNUSED(original)
+    m_window = deleted;
 }
 
 QMatrix4x4 SurfaceItem::surfaceToBufferMatrix() const
@@ -39,8 +53,7 @@ void SurfaceItem::addDamage(const QRegion &region)
     m_damage += region;
     scheduleRepaint(region);
 
-    Toplevel *toplevel = window()->window();
-    Q_EMIT toplevel->damaged(toplevel, region);
+    Q_EMIT m_window->damaged(m_window, region);
 }
 
 void SurfaceItem::resetDamage()

src/surfaceitem.h

@@ -11,7 +11,9 @@
 namespace KWin
 {
 
+class Deleted;
 class SurfacePixmap;
+class Toplevel;
 
 /**
  * The SurfaceItem class represents a surface with some contents.
@@ -24,6 +26,8 @@ public:
     QMatrix4x4 surfaceToBufferMatrix() const;
     void setSurfaceToBufferMatrix(const QMatrix4x4 &matrix);
 
+    Toplevel *window() const;
+
     virtual QRegion shape() const;
     virtual QRegion opaque() const;
 
@@ -41,12 +45,15 @@ public:
     void unreferencePreviousPixmap();
 
 protected:
-    explicit SurfaceItem(Scene::Window *window, Item *parent = nullptr);
+    explicit SurfaceItem(Toplevel *window, Item *parent = nullptr);
 
     virtual SurfacePixmap *createPixmap() = 0;
     void preprocess() override;
     WindowQuadList buildQuads() const override;
 
+    void handleWindowClosed(Toplevel *original, Deleted *deleted);
+
+    Toplevel *m_window;
     QRegion m_damage;
     QScopedPointer<SurfacePixmap> m_pixmap;
     QScopedPointer<SurfacePixmap> m_previousPixmap;

src/surfaceitem_internal.cpp

@@ -11,19 +11,17 @@
 namespace KWin
 {
 
-SurfaceItemInternal::SurfaceItemInternal(Scene::Window *window, Item *parent)
+SurfaceItemInternal::SurfaceItemInternal(Toplevel *window, Item *parent)
     : SurfaceItem(window, parent)
 {
-    Toplevel *toplevel = window->window();
-
-    connect(toplevel, &Toplevel::bufferGeometryChanged,
+    connect(window, &Toplevel::bufferGeometryChanged,
             this, &SurfaceItemInternal::handleBufferGeometryChanged);
 
-    setSize(toplevel->bufferGeometry().size());
+    setSize(window->bufferGeometry().size());
 
     // The device pixel ratio of the internal window is static.
     QMatrix4x4 surfaceToBufferMatrix;
-    surfaceToBufferMatrix.scale(toplevel->bufferScale());
+    surfaceToBufferMatrix.scale(window->bufferScale());
     setSurfaceToBufferMatrix(surfaceToBufferMatrix);
 }
 
@@ -68,13 +66,13 @@ void SurfacePixmapInternal::create()
 
 void SurfacePixmapInternal::update()
 {
-    const Toplevel *toplevel = m_item->window()->window();
+    const Toplevel *window = m_item->window();
 
-    if (toplevel->internalFramebufferObject()) {
-        m_fbo = toplevel->internalFramebufferObject();
+    if (window->internalFramebufferObject()) {
+        m_fbo = window->internalFramebufferObject();
         m_hasAlphaChannel = true;
-    } else if (!toplevel->internalImageObject().isNull()) {
-        m_rasterBuffer = toplevel->internalImageObject();
+    } else if (!window->internalImageObject().isNull()) {
+        m_rasterBuffer = window->internalImageObject();
         m_hasAlphaChannel = m_rasterBuffer.hasAlphaChannel();
     }
 }

src/surfaceitem_internal.h

@@ -8,6 +8,8 @@
 
 #include "surfaceitem.h"
 
+class QOpenGLFramebufferObject;
+
 namespace KWin
 {
 
@@ -19,7 +21,7 @@ class KWIN_EXPORT SurfaceItemInternal : public SurfaceItem
     Q_OBJECT
 
 public:
-    explicit SurfaceItemInternal(Scene::Window *window, Item *parent = nullptr);
+    explicit SurfaceItemInternal(Toplevel *window, Item *parent = nullptr);
 
     QRegion shape() const override;
 

src/surfaceitem_wayland.cpp

@@ -16,7 +16,7 @@ namespace KWin
 {
 
 SurfaceItemWayland::SurfaceItemWayland(KWaylandServer::SurfaceInterface *surface,
-                                       Scene::Window *window, Item *parent)
+                                       Toplevel *window, Item *parent)
     : SurfaceItem(window, parent)
     , m_surface(surface)
 {
@@ -197,18 +197,16 @@ void SurfacePixmapWayland::setBuffer(KWaylandServer::ClientBuffer *buffer)
     }
 }
 
-SurfaceItemXwayland::SurfaceItemXwayland(Scene::Window *window, Item *parent)
-    : SurfaceItemWayland(window->window()->surface(), window, parent)
+SurfaceItemXwayland::SurfaceItemXwayland(Toplevel *window, Item *parent)
+    : SurfaceItemWayland(window->surface(), window, parent)
 {
-    const Toplevel *toplevel = window->window();
-    connect(toplevel, &Toplevel::geometryShapeChanged, this, &SurfaceItemXwayland::discardQuads);
+    connect(window, &Toplevel::geometryShapeChanged, this, &SurfaceItemXwayland::discardQuads);
 }
 
 QRegion SurfaceItemXwayland::shape() const
 {
-    const Toplevel *toplevel = window()->window();
-    const QRect clipRect = rect() & toplevel->clientGeometry().translated(-toplevel->bufferGeometry().topLeft());
-    const QRegion shape = toplevel->shapeRegion();
+    const QRect clipRect = rect() & window()->clientGeometry().translated(-window()->bufferGeometry().topLeft());
+    const QRegion shape = window()->shapeRegion();
 
     return shape & clipRect;
 }

src/surfaceitem_wayland.h

@@ -27,7 +27,7 @@ class KWIN_EXPORT SurfaceItemWayland : public SurfaceItem
 
 public:
     explicit SurfaceItemWayland(KWaylandServer::SurfaceInterface *surface,
-                                Scene::Window *window, Item *parent = nullptr);
+                                Toplevel *window, Item *parent = nullptr);
 
     QRegion shape() const override;
     QRegion opaque() const override;
@@ -85,7 +85,7 @@ class KWIN_EXPORT SurfaceItemXwayland : public SurfaceItemWayland
     Q_OBJECT
 
 public:
-    explicit SurfaceItemXwayland(Scene::Window *window, Item *parent = nullptr);
+    explicit SurfaceItemXwayland(Toplevel *window, Item *parent = nullptr);
 
     QRegion shape() const override;
 };

src/surfaceitem_x11.cpp

@@ -12,21 +12,19 @@
 namespace KWin
 {
 
-SurfaceItemX11::SurfaceItemX11(Scene::Window *window, Item *parent)
+SurfaceItemX11::SurfaceItemX11(Toplevel *window, Item *parent)
     : SurfaceItem(window, parent)
 {
-    Toplevel *toplevel = window->window();
-
-    connect(toplevel, &Toplevel::bufferGeometryChanged,
+    connect(window, &Toplevel::bufferGeometryChanged,
             this, &SurfaceItemX11::handleBufferGeometryChanged);
-    connect(toplevel, &Toplevel::geometryShapeChanged,
+    connect(window, &Toplevel::geometryShapeChanged,
             this, &SurfaceItemX11::discardQuads);
 
     m_damageHandle = xcb_generate_id(kwinApp()->x11Connection());
-    xcb_damage_create(kwinApp()->x11Connection(), m_damageHandle, toplevel->frameId(),
+    xcb_damage_create(kwinApp()->x11Connection(), m_damageHandle, window->frameId(),
                       XCB_DAMAGE_REPORT_LEVEL_NON_EMPTY);
 
-    setSize(toplevel->bufferGeometry().size());
+    setSize(window->bufferGeometry().size());
 }
 
 SurfaceItemX11::~SurfaceItemX11()
@@ -127,16 +125,15 @@ void SurfaceItemX11::handleBufferGeometryChanged(Toplevel *toplevel, const QRect
 
 QRegion SurfaceItemX11::shape() const
 {
-    const Toplevel *toplevel = window()->window();
-    const QRect clipRect = toplevel->clientGeometry().translated(-toplevel->bufferGeometry().topLeft());
-    const QRegion shape = toplevel->shapeRegion();
+    const QRect clipRect = window()->clientGeometry().translated(-window()->bufferGeometry().topLeft());
+    const QRegion shape = window()->shapeRegion();
 
     return shape & clipRect;
 }
 
 QRegion SurfaceItemX11::opaque() const
 {
-    return window()->window()->opaqueRegion();
+    return window()->opaqueRegion();
 }
 
 SurfacePixmap *SurfaceItemX11::createPixmap()
@@ -169,12 +166,12 @@ xcb_pixmap_t SurfacePixmapX11::pixmap() const
 
 xcb_visualid_t SurfacePixmapX11::visual() const
 {
-    return m_item->window()->window()->visual();
+    return m_item->window()->visual();
 }
 
 void SurfacePixmapX11::create()
 {
-    const Toplevel *toplevel = m_item->window()->window();
+    const Toplevel *toplevel = m_item->window();
     if (toplevel->isDeleted()) {
         return;
     }

src/surfaceitem_x11.h

@@ -8,6 +8,9 @@
 
 #include "surfaceitem.h"
 
+#include <xcb/damage.h>
+#include <xcb/xfixes.h>
+
 namespace KWin
 {
 
@@ -19,7 +22,7 @@ class KWIN_EXPORT SurfaceItemX11 : public SurfaceItem
     Q_OBJECT
 
 public:
-    explicit SurfaceItemX11(Scene::Window *window, Item *parent = nullptr);
+    explicit SurfaceItemX11(Toplevel *window, Item *parent = nullptr);
     ~SurfaceItemX11() override;
 
     void preprocess() override;

src/windowitem.cpp

@@ -7,6 +7,7 @@
 #include "windowitem.h"
 #include "abstract_client.h"
 #include "decorationitem.h"
+#include "deleted.h"
 #include "shadowitem.h"
 #include "surfaceitem_internal.h"
 #include "surfaceitem_wayland.h"
@@ -15,14 +16,16 @@
 namespace KWin
 {
 
-WindowItem::WindowItem(Scene::Window *window, Item *parent)
-    : Item(window, parent)
+WindowItem::WindowItem(Toplevel *window, Item *parent)
+    : Item(parent)
+    , m_window(window)
 {
-    AbstractClient *client = qobject_cast<AbstractClient *>(window->window());
+    AbstractClient *client = qobject_cast<AbstractClient *>(window);
     if (client) {
         connect(client, &AbstractClient::decorationChanged, this, &WindowItem::updateDecorationItem);
         updateDecorationItem();
     }
+    connect(window, &Toplevel::windowClosed, this, &WindowItem::handleWindowClosed);
 }
 
 SurfaceItem *WindowItem::surfaceItem() const
@@ -40,15 +43,24 @@ ShadowItem *WindowItem::shadowItem() const
     return m_shadowItem.data();
 }
 
+Toplevel *WindowItem::window() const
+{
+    return m_window;
+}
+
+void WindowItem::handleWindowClosed(Toplevel *original, Deleted *deleted)
+{
+    Q_UNUSED(original)
+    m_window = deleted;
+}
+
 void WindowItem::updateSurfaceItem(SurfaceItem *surfaceItem)
 {
-    Toplevel *toplevel = window()->window();
-
     m_surfaceItem.reset(surfaceItem);
 
-    connect(toplevel, &Toplevel::shadeChanged, this, &WindowItem::updateSurfaceVisibility);
-    connect(toplevel, &Toplevel::bufferGeometryChanged, this, &WindowItem::updateSurfacePosition);
-    connect(toplevel, &Toplevel::frameGeometryChanged, this, &WindowItem::updateSurfacePosition);
+    connect(m_window, &Toplevel::shadeChanged, this, &WindowItem::updateSurfaceVisibility);
+    connect(m_window, &Toplevel::bufferGeometryChanged, this, &WindowItem::updateSurfacePosition);
+    connect(m_window, &Toplevel::frameGeometryChanged, this, &WindowItem::updateSurfacePosition);
 
     updateSurfacePosition();
     updateSurfaceVisibility();
@@ -56,24 +68,22 @@ void WindowItem::updateSurfaceItem(SurfaceItem *surfaceItem)
 
 void WindowItem::updateSurfacePosition()
 {
-    const Toplevel *toplevel = window()->window();
-
-    const QRect bufferGeometry = toplevel->bufferGeometry();
-    const QRect frameGeometry = toplevel->frameGeometry();
+    const QRect bufferGeometry = m_window->bufferGeometry();
+    const QRect frameGeometry = m_window->frameGeometry();
 
     m_surfaceItem->setPosition(bufferGeometry.topLeft() - frameGeometry.topLeft());
 }
 
 void WindowItem::updateSurfaceVisibility()
 {
-    m_surfaceItem->setVisible(!window()->window()->isShade());
+    m_surfaceItem->setVisible(!m_window->isShade());
 }
 
 void WindowItem::setShadow(Shadow *shadow)
 {
     if (shadow) {
         if (!m_shadowItem || m_shadowItem->shadow() != shadow) {
-            m_shadowItem.reset(new ShadowItem(shadow, window(), this));
+            m_shadowItem.reset(new ShadowItem(shadow, m_window, this));
         }
         if (m_decorationItem) {
             m_shadowItem->stackBefore(m_decorationItem.data());
@@ -87,12 +97,12 @@ void WindowItem::setShadow(Shadow *shadow)
 
 void WindowItem::updateDecorationItem()
 {
-    AbstractClient *client = qobject_cast<AbstractClient *>(window()->window());
+    AbstractClient *client = qobject_cast<AbstractClient *>(m_window);
     if (!client || client->isZombie()) {
         return;
     }
     if (client->decoration()) {
-        m_decorationItem.reset(new DecorationItem(client->decoration(), window(), this));
+        m_decorationItem.reset(new DecorationItem(client->decoration(), client, this));
         if (m_shadowItem) {
             m_decorationItem->stackAfter(m_shadowItem.data());
         } else if (m_surfaceItem) {
@@ -103,21 +113,19 @@ void WindowItem::updateDecorationItem()
     }
 }
 
-WindowItemX11::WindowItemX11(Scene::Window *window, Item *parent)
+WindowItemX11::WindowItemX11(Toplevel *window, Item *parent)
     : WindowItem(window, parent)
 {
-    Toplevel *toplevel = window->window();
-
     switch (kwinApp()->operationMode()) {
     case Application::OperationModeX11:
         initialize();
         break;
     case Application::OperationModeXwayland:
         // Xwayland windows and Wayland surfaces are associated asynchronously.
-        if (toplevel->surface()) {
+        if (window->surface()) {
             initialize();
         } else {
-            connect(toplevel, &Toplevel::surfaceChanged, this, &WindowItemX11::initialize);
+            connect(window, &Toplevel::surfaceChanged, this, &WindowItemX11::initialize);
         }
         break;
     case Application::OperationModeWaylandOnly:
@@ -127,21 +135,20 @@ WindowItemX11::WindowItemX11(Scene::Window *window, Item *parent)
 
 void WindowItemX11::initialize()
 {
-    if (!window()->window()->surface()) {
+    if (!window()->surface()) {
         updateSurfaceItem(new SurfaceItemX11(window(), this));
     } else {
         updateSurfaceItem(new SurfaceItemXwayland(window(), this));
     }
 }
 
-WindowItemWayland::WindowItemWayland(Scene::Window *window, Item *parent)
+WindowItemWayland::WindowItemWayland(Toplevel *window, Item *parent)
     : WindowItem(window, parent)
 {
-    Toplevel *toplevel = window->window();
-    updateSurfaceItem(new SurfaceItemWayland(toplevel->surface(), window, this));
+    updateSurfaceItem(new SurfaceItemWayland(window->surface(), window, this));
 }
 
-WindowItemInternal::WindowItemInternal(Scene::Window *window, Item *parent)
+WindowItemInternal::WindowItemInternal(Toplevel *window, Item *parent)
     : WindowItem(window, parent)
 {
     updateSurfaceItem(new SurfaceItemInternal(window, this));

src/windowitem.h

@@ -16,6 +16,11 @@ class Decoration;
 namespace KWin
 {
 class DecorationItem;
+class Deleted;
+class Shadow;
+class ShadowItem;
+class SurfaceItem;
+class Toplevel;
 
 /**
  * The WindowItem class represents a window in the scene.
@@ -31,19 +36,22 @@ public:
     SurfaceItem *surfaceItem() const;
     DecorationItem *decorationItem() const;
     ShadowItem *shadowItem() const;
+    Toplevel *window() const;
 
     void setShadow(Shadow *shadow);
 
 protected:
-    explicit WindowItem(Scene::Window *window, Item *parent = nullptr);
+    explicit WindowItem(Toplevel *window, Item *parent = nullptr);
     void updateSurfaceItem(SurfaceItem *surfaceItem);
 
 private Q_SLOTS:
+    void handleWindowClosed(Toplevel *original, Deleted *deleted);
     void updateDecorationItem();
     void updateSurfacePosition();
     void updateSurfaceVisibility();
 
 private:
+    Toplevel *m_window;
     QScopedPointer<SurfaceItem> m_surfaceItem;
     QScopedPointer<DecorationItem> m_decorationItem;
     QScopedPointer<ShadowItem> m_shadowItem;
@@ -60,7 +68,7 @@ class KWIN_EXPORT WindowItemX11 : public WindowItem
     Q_OBJECT
 
 public:
-    explicit WindowItemX11(Scene::Window *window, Item *parent = nullptr);
+    explicit WindowItemX11(Toplevel *window, Item *parent = nullptr);
 
 private Q_SLOTS:
     void initialize();
@@ -74,7 +82,7 @@ class KWIN_EXPORT WindowItemWayland : public WindowItem
     Q_OBJECT
 
 public:
-    explicit WindowItemWayland(Scene::Window *window, Item *parent = nullptr);
+    explicit WindowItemWayland(Toplevel *window, Item *parent = nullptr);
 };
 
 /**
@@ -86,7 +94,7 @@ class KWIN_EXPORT WindowItemInternal : public WindowItem
     Q_OBJECT
 
 public:
-    explicit WindowItemInternal(Scene::Window *window, Item *parent = nullptr);
+    explicit WindowItemInternal(Toplevel *window, Item *parent = nullptr);
 };
 
 } // namespace KWin