File indexing completed on 2024-04-28 16:48:40

 /*
     KWin - the KDE window manager
     This file is part of the KDE project.
 
     SPDX-FileCopyrightText: 2006 Lubos Lunak <l.lunak@kde.org>
 
     SPDX-License-Identifier: GPL-2.0-or-later
 */
 #include "composite.h"
 
 #include <config-kwin.h>
 
 #include "core/output.h"
 #include "core/outputbackend.h"
 #include "core/outputlayer.h"
 #include "core/overlaywindow.h"
 #include "core/renderlayer.h"
 #include "core/renderloop.h"
 #include "cursordelegate_opengl.h"
 #include "cursordelegate_qpainter.h"
 #include "dbusinterface.h"
 #include "decorations/decoratedclient.h"
 #include "deleted.h"
 #include "effects.h"
 #include "ftrace.h"
 #include "internalwindow.h"
 #include "openglbackend.h"
 #include "qpainterbackend.h"
 #include "scene/cursorscene.h"
 #include "scene/itemrenderer_opengl.h"
 #include "scene/itemrenderer_qpainter.h"
 #include "scene/surfaceitem_x11.h"
 #include "scene/workspacescene_opengl.h"
 #include "scene/workspacescene_qpainter.h"
 #include "shadow.h"
 #include "unmanaged.h"
 #include "useractions.h"
 #include "utils/common.h"
 #include "utils/xcbutils.h"
 #include "wayland/surface_interface.h"
 #include "wayland_server.h"
 #include "workspace.h"
 #include "x11syncmanager.h"
 #include "x11window.h"
 
 #include <kwinglplatform.h>
 #include <kwingltexture.h>
 
 #include <KCrash>
 #include <KGlobalAccel>
 #include <KLocalizedString>
 #if KWIN_BUILD_NOTIFICATIONS
 #include <KNotification>
 #endif
 #include <KSelectionOwner>
 
 #include <QDateTime>
 #include <QFutureWatcher>
 #include <QMenu>
 #include <QOpenGLContext>
 #include <QQuickWindow>
 #include <QTextStream>
 #include <QTimerEvent>
 #include <QtConcurrentRun>
 
 #include <xcb/composite.h>
 #include <xcb/damage.h>
 
 #include <cstdio>
 
 Q_DECLARE_METATYPE(KWin::X11Compositor::SuspendReason)
 
 namespace KWin
 {
 
 Compositor *Compositor::s_compositor = nullptr;
 Compositor *Compositor::self()
 {
     return s_compositor;
 }
 
 WaylandCompositor *WaylandCompositor::create(QObject *parent)
 {
     Q_ASSERT(!s_compositor);
     auto *compositor = new WaylandCompositor(parent);
     s_compositor = compositor;
     return compositor;
 }
 X11Compositor *X11Compositor::create(QObject *parent)
 {
     Q_ASSERT(!s_compositor);
     auto *compositor = new X11Compositor(parent);
     s_compositor = compositor;
     return compositor;
 }
 
 class CompositorSelectionOwner : public KSelectionOwner
 {
     Q_OBJECT
 public:
     CompositorSelectionOwner(const char *selection)
         : KSelectionOwner(selection, kwinApp()->x11Connection(), kwinApp()->x11RootWindow())
         , m_owning(false)
     {
         connect(this, &CompositorSelectionOwner::lostOwnership,
                 this, [this]() {
                     m_owning = false;
                 });
     }
     bool owning() const
     {
         return m_owning;
     }
     void setOwning(bool own)
     {
         m_owning = own;
     }
 
 private:
     bool m_owning;
 };
 
 Compositor::Compositor(QObject *workspace)
     : QObject(workspace)
 {
     connect(options, &Options::configChanged, this, &Compositor::configChanged);
     connect(options, &Options::animationSpeedChanged, this, &Compositor::configChanged);
 
     // 2 sec which should be enough to restart the compositor.
     static const int compositorLostMessageDelay = 2000;
 
     m_releaseSelectionTimer.setSingleShot(true);
     m_releaseSelectionTimer.setInterval(compositorLostMessageDelay);
     connect(&m_releaseSelectionTimer, &QTimer::timeout,
             this, &Compositor::releaseCompositorSelection);
 
     m_unusedSupportPropertyTimer.setInterval(compositorLostMessageDelay);
     m_unusedSupportPropertyTimer.setSingleShot(true);
     connect(&m_unusedSupportPropertyTimer, &QTimer::timeout,
             this, &Compositor::deleteUnusedSupportProperties);
 
     // Delay the call to start by one event cycle.
     // The ctor of this class is invoked from the Workspace ctor, that means before
     // Workspace is completely constructed, so calling Workspace::self() would result
     // in undefined behavior. This is fixed by using a delayed invocation.
     QTimer::singleShot(0, this, &Compositor::start);
 
     connect(kwinApp(), &Application::x11ConnectionChanged, this, &Compositor::initializeX11);
     connect(kwinApp(), &Application::x11ConnectionAboutToBeDestroyed, this, &Compositor::cleanupX11);
 
     // register DBus
     new CompositorDBusInterface(this);
     FTraceLogger::create();
 }
 
 Compositor::~Compositor()
 {
     deleteUnusedSupportProperties();
     destroyCompositorSelection();
     s_compositor = nullptr;
 }
 
 bool Compositor::attemptOpenGLCompositing()
 {
     // Some broken drivers crash on glXQuery() so to prevent constant KWin crashes:
     if (openGLCompositingIsBroken()) {
         qCWarning(KWIN_CORE) << "KWin has detected that your OpenGL library is unsafe to use";
         return false;
     }
 
     createOpenGLSafePoint(OpenGLSafePoint::PreInit);
     auto safePointScope = qScopeGuard([this]() {
         createOpenGLSafePoint(OpenGLSafePoint::PostInit);
     });
 
     std::unique_ptr<OpenGLBackend> backend = kwinApp()->outputBackend()->createOpenGLBackend();
     if (!backend) {
         return false;
     }
     if (!backend->isFailed()) {
         backend->init();
     }
     if (backend->isFailed()) {
         return false;
     }
 
     const QByteArray forceEnv = qgetenv("KWIN_COMPOSE");
     if (!forceEnv.isEmpty()) {
         if (qstrcmp(forceEnv, "O2") == 0 || qstrcmp(forceEnv, "O2ES") == 0) {
             qCDebug(KWIN_CORE) << "OpenGL 2 compositing enforced by environment variable";
         } else {
             // OpenGL 2 disabled by environment variable
             return false;
         }
     } else {
         if (!backend->isDirectRendering()) {
             return false;
         }
         if (GLPlatform::instance()->recommendedCompositor() < OpenGLCompositing) {
             qCDebug(KWIN_CORE) << "Driver does not recommend OpenGL compositing";
             return false;
         }
     }
 
     // We only support the OpenGL 2+ shader API, not GL_ARB_shader_objects
     if (!hasGLVersion(2, 0)) {
         qCDebug(KWIN_CORE) << "OpenGL 2.0 is not supported";
         return false;
     }
 
     m_scene = std::make_unique<WorkspaceSceneOpenGL>(backend.get());
     m_cursorScene = std::make_unique<CursorScene>(std::make_unique<ItemRendererOpenGL>());
     m_backend = std::move(backend);
 
     // set strict binding
     if (options->isGlStrictBindingFollowsDriver()) {
         options->setGlStrictBinding(!GLPlatform::instance()->supports(LooseBinding));
     }
 
     qCDebug(KWIN_CORE) << "OpenGL compositing has been successfully initialized";
     return true;
 }
 
 bool Compositor::attemptQPainterCompositing()
 {
     std::unique_ptr<QPainterBackend> backend(kwinApp()->outputBackend()->createQPainterBackend());
     if (!backend || backend->isFailed()) {
         return false;
     }
 
     m_scene = std::make_unique<WorkspaceSceneQPainter>(backend.get());
     m_cursorScene = std::make_unique<CursorScene>(std::make_unique<ItemRendererQPainter>());
     m_backend = std::move(backend);
 
     qCDebug(KWIN_CORE) << "QPainter compositing has been successfully initialized";
     return true;
 }
 
 bool Compositor::setupStart()
 {
     if (kwinApp()->isTerminating()) {
         // Don't start while KWin is terminating. An event to restart might be lingering
         // in the event queue due to graphics reset.
         return false;
     }
     if (m_state != State::Off) {
         return false;
     }
     m_state = State::Starting;
 
     options->reloadCompositingSettings(true);
 
     initializeX11();
 
     // There might still be a deleted around, needs to be cleared before
     // creating the scene (BUG 333275).
     if (Workspace::self()) {
         while (!Workspace::self()->deletedList().isEmpty()) {
             Workspace::self()->deletedList().first()->discard();
         }
     }
 
     Q_EMIT aboutToToggleCompositing();
 
     const QVector<CompositingType> availableCompositors = kwinApp()->outputBackend()->supportedCompositors();
     QVector<CompositingType> candidateCompositors;
 
     // If compositing has been restarted, try to use the last used compositing type.
     if (m_selectedCompositor != NoCompositing) {
         candidateCompositors.append(m_selectedCompositor);
     } else {
         candidateCompositors = availableCompositors;
 
         const auto userConfigIt = std::find(candidateCompositors.begin(), candidateCompositors.end(), options->compositingMode());
         if (userConfigIt != candidateCompositors.end()) {
             candidateCompositors.erase(userConfigIt);
             candidateCompositors.prepend(options->compositingMode());
         } else {
             qCWarning(KWIN_CORE) << "Configured compositor not supported by Platform. Falling back to defaults";
         }
     }
 
     for (auto type : std::as_const(candidateCompositors)) {
         bool stop = false;
         switch (type) {
         case OpenGLCompositing:
             qCDebug(KWIN_CORE) << "Attempting to load the OpenGL scene";
             stop = attemptOpenGLCompositing();
             break;
         case QPainterCompositing:
             qCDebug(KWIN_CORE) << "Attempting to load the QPainter scene";
             stop = attemptQPainterCompositing();
             break;
         case NoCompositing:
             qCDebug(KWIN_CORE) << "Starting without compositing...";
             stop = true;
             break;
         }
 
         if (stop) {
             break;
         }
     }
 
     if (!m_backend) {
         m_state = State::Off;
 
         if (auto *con = kwinApp()->x11Connection()) {
             xcb_composite_unredirect_subwindows(con, kwinApp()->x11RootWindow(),
                                                 XCB_COMPOSITE_REDIRECT_MANUAL);
         }
         if (m_selectionOwner) {
             m_selectionOwner->setOwning(false);
             m_selectionOwner->release();
         }
         if (!availableCompositors.contains(NoCompositing)) {
             qCCritical(KWIN_CORE) << "The used windowing system requires compositing";
             qCCritical(KWIN_CORE) << "We are going to quit KWin now as it is broken";
             qApp->quit();
         }
         return false;
     }
 
     m_selectedCompositor = m_backend->compositingType();
 
     if (!Workspace::self() && m_backend && m_backend->compositingType() == QPainterCompositing) {
         // Force Software QtQuick on first startup with QPainter.
 #if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
         QQuickWindow::setSceneGraphBackend(QSGRendererInterface::Software);
 #else
         QQuickWindow::setGraphicsApi(QSGRendererInterface::Software);
 #endif
     }
 
     Q_EMIT sceneCreated();
 
     return true;
 }
 
 void Compositor::initializeX11()
 {
     xcb_connection_t *connection = kwinApp()->x11Connection();
     if (!connection) {
         return;
     }
 
     if (!m_selectionOwner) {
         m_selectionOwner = std::make_unique<CompositorSelectionOwner>("_NET_WM_CM_S0");
         connect(m_selectionOwner.get(), &CompositorSelectionOwner::lostOwnership, this, &Compositor::stop);
     }
     if (!m_selectionOwner->owning()) {
         // Force claim ownership.
         m_selectionOwner->claim(true);
         m_selectionOwner->setOwning(true);
     }
 
     xcb_composite_redirect_subwindows(connection, kwinApp()->x11RootWindow(),
                                       XCB_COMPOSITE_REDIRECT_MANUAL);
 }
 
 void Compositor::cleanupX11()
 {
     m_selectionOwner.reset();
 }
 
 void Compositor::startupWithWorkspace()
 {
     Q_ASSERT(m_scene);
     m_scene->initialize();
     m_cursorScene->initialize();
 
     const QList<Output *> outputs = workspace()->outputs();
     if (kwinApp()->operationMode() == Application::OperationModeX11) {
         auto workspaceLayer = new RenderLayer(outputs.constFirst()->renderLoop());
         workspaceLayer->setDelegate(std::make_unique<SceneDelegate>(m_scene.get()));
         workspaceLayer->setGeometry(workspace()->geometry());
         connect(workspace(), &Workspace::geometryChanged, workspaceLayer, [workspaceLayer]() {
             workspaceLayer->setGeometry(workspace()->geometry());
         });
         addSuperLayer(workspaceLayer);
     } else {
         for (Output *output : outputs) {
             addOutput(output);
         }
         connect(workspace(), &Workspace::outputAdded, this, &Compositor::addOutput);
         connect(workspace(), &Workspace::outputRemoved, this, &Compositor::removeOutput);
     }
 
     m_state = State::On;
 
     for (X11Window *window : Workspace::self()->clientList()) {
         window->setupCompositing();
     }
     for (Unmanaged *window : Workspace::self()->unmanagedList()) {
         window->setupCompositing();
     }
     for (InternalWindow *window : workspace()->internalWindows()) {
         window->setupCompositing();
     }
 
     if (auto *server = waylandServer()) {
         const auto windows = server->windows();
         for (Window *window : windows) {
             window->setupCompositing();
         }
     }
 
     // Sets also the 'effects' pointer.
     kwinApp()->createEffectsHandler(this, m_scene.get());
 
     Q_EMIT compositingToggled(true);
 
     if (m_releaseSelectionTimer.isActive()) {
         m_releaseSelectionTimer.stop();
     }
 }
 
 Output *Compositor::findOutput(RenderLoop *loop) const
 {
     const auto outputs = workspace()->outputs();
     for (Output *output : outputs) {
         if (output->renderLoop() == loop) {
             return output;
         }
     }
     return nullptr;
 }
 
 void Compositor::addOutput(Output *output)
 {
     Q_ASSERT(kwinApp()->operationMode() != Application::OperationModeX11);
 
     auto workspaceLayer = new RenderLayer(output->renderLoop());
     workspaceLayer->setDelegate(std::make_unique<SceneDelegate>(m_scene.get(), output));
     workspaceLayer->setGeometry(output->rect());
     connect(output, &Output::geometryChanged, workspaceLayer, [output, workspaceLayer]() {
         workspaceLayer->setGeometry(output->rect());
     });
 
     auto cursorLayer = new RenderLayer(output->renderLoop());
     cursorLayer->setVisible(false);
     if (m_backend->compositingType() == OpenGLCompositing) {
         cursorLayer->setDelegate(std::make_unique<CursorDelegateOpenGL>());
     } else {
         cursorLayer->setDelegate(std::make_unique<CursorDelegateQPainter>());
     }
     cursorLayer->setParent(workspaceLayer);
     cursorLayer->setSuperlayer(workspaceLayer);
 
     auto updateCursorLayer = [output, cursorLayer]() {
         const Cursor *cursor = Cursors::self()->currentCursor();
         const QRect layerRect = output->mapFromGlobal(cursor->geometry());
         bool usesHardwareCursor = false;
         if (!Cursors::self()->isCursorHidden()) {
             usesHardwareCursor = output->setCursor(cursor->source()) && output->moveCursor(layerRect.topLeft());
         } else {
             usesHardwareCursor = output->setCursor(nullptr);
         }
         cursorLayer->setVisible(cursor->isOnOutput(output) && !usesHardwareCursor);
         cursorLayer->setGeometry(layerRect);
         cursorLayer->addRepaintFull();
     };
     auto moveCursorLayer = [output, cursorLayer]() {
         const Cursor *cursor = Cursors::self()->currentCursor();
         const QRect layerRect = output->mapFromGlobal(cursor->geometry());
         const bool usesHardwareCursor = output->moveCursor(layerRect.topLeft());
         cursorLayer->setVisible(cursor->isOnOutput(output) && !usesHardwareCursor);
         cursorLayer->setGeometry(layerRect);
         cursorLayer->addRepaintFull();
     };
     updateCursorLayer();
     connect(output, &Output::geometryChanged, cursorLayer, updateCursorLayer);
     connect(Cursors::self(), &Cursors::currentCursorChanged, cursorLayer, updateCursorLayer);
     connect(Cursors::self(), &Cursors::hiddenChanged, cursorLayer, updateCursorLayer);
     connect(Cursors::self(), &Cursors::positionChanged, cursorLayer, moveCursorLayer);
 
     addSuperLayer(workspaceLayer);
 }
 
 void Compositor::removeOutput(Output *output)
 {
     removeSuperLayer(m_superlayers[output->renderLoop()]);
 }
 
 void Compositor::addSuperLayer(RenderLayer *layer)
 {
     m_superlayers.insert(layer->loop(), layer);
     connect(layer->loop(), &RenderLoop::frameRequested, this, &Compositor::handleFrameRequested);
 }
 
 void Compositor::removeSuperLayer(RenderLayer *layer)
 {
     m_superlayers.remove(layer->loop());
     disconnect(layer->loop(), &RenderLoop::frameRequested, this, &Compositor::handleFrameRequested);
     delete layer;
 }
 
 void Compositor::scheduleRepaint()
 {
     for (auto it = m_superlayers.constBegin(); it != m_superlayers.constEnd(); ++it) {
         it.key()->scheduleRepaint();
     }
 }
 
 void Compositor::stop()
 {
     if (m_state == State::Off || m_state == State::Stopping) {
         return;
     }
     m_state = State::Stopping;
     Q_EMIT aboutToToggleCompositing();
 
     m_releaseSelectionTimer.start();
 
     // Some effects might need access to effect windows when they are about to
     // be destroyed, for example to unreference deleted windows, so we have to
     // make sure that effect windows outlive effects.
     delete effects;
     effects = nullptr;
 
     if (Workspace::self()) {
         for (X11Window *window : Workspace::self()->clientList()) {
             window->finishCompositing();
         }
         for (Unmanaged *window : Workspace::self()->unmanagedList()) {
             window->finishCompositing();
         }
         for (InternalWindow *window : workspace()->internalWindows()) {
             window->finishCompositing();
         }
         if (auto *con = kwinApp()->x11Connection()) {
             xcb_composite_unredirect_subwindows(con, kwinApp()->x11RootWindow(),
                                                 XCB_COMPOSITE_REDIRECT_MANUAL);
         }
         while (!workspace()->deletedList().isEmpty()) {
             workspace()->deletedList().first()->discard();
         }
 
         disconnect(workspace(), &Workspace::outputAdded, this, &Compositor::addOutput);
         disconnect(workspace(), &Workspace::outputRemoved, this, &Compositor::removeOutput);
     }
 
     if (waylandServer()) {
         const QList<Window *> toFinishCompositing = waylandServer()->windows();
         for (Window *window : toFinishCompositing) {
             window->finishCompositing();
         }
     }
 
     const auto superlayers = m_superlayers;
     for (auto it = superlayers.begin(); it != superlayers.end(); ++it) {
         removeSuperLayer(*it);
     }
 
     m_scene.reset();
     m_cursorScene.reset();
     m_backend.reset();
 
     m_state = State::Off;
     Q_EMIT compositingToggled(false);
 }
 
 void Compositor::destroyCompositorSelection()
 {
     m_selectionOwner.reset();
 }
 
 void Compositor::releaseCompositorSelection()
 {
     switch (m_state) {
     case State::On:
         // We are compositing at the moment. Don't release.
         break;
     case State::Off:
         if (m_selectionOwner) {
             qCDebug(KWIN_CORE) << "Releasing compositor selection";
             m_selectionOwner->setOwning(false);
             m_selectionOwner->release();
         }
         break;
     case State::Starting:
     case State::Stopping:
         // Still starting or shutting down the compositor. Starting might fail
         // or after stopping a restart might follow. So test again later on.
         m_releaseSelectionTimer.start();
         break;
     }
 }
 
 void Compositor::keepSupportProperty(xcb_atom_t atom)
 {
     m_unusedSupportProperties.removeAll(atom);
 }
 
 void Compositor::removeSupportProperty(xcb_atom_t atom)
 {
     m_unusedSupportProperties << atom;
     m_unusedSupportPropertyTimer.start();
 }
 
 void Compositor::deleteUnusedSupportProperties()
 {
     if (m_state == State::Starting || m_state == State::Stopping) {
         // Currently still maybe restarting the compositor.
         m_unusedSupportPropertyTimer.start();
         return;
     }
     if (auto *con = kwinApp()->x11Connection()) {
         for (const xcb_atom_t &atom : std::as_const(m_unusedSupportProperties)) {
             // remove property from root window
             xcb_delete_property(con, kwinApp()->x11RootWindow(), atom);
         }
         m_unusedSupportProperties.clear();
     }
 }
 
 void Compositor::configChanged()
 {
     reinitialize();
 }
 
 void Compositor::reinitialize()
 {
     // Reparse config. Config options will be reloaded by start()
     kwinApp()->config()->reparseConfiguration();
 
     // Restart compositing
     stop();
     start();
 
     if (effects) { // start() may fail
         effects->reconfigure();
     }
 }
 
 void Compositor::handleFrameRequested(RenderLoop *renderLoop)
 {
     composite(renderLoop);
 }
 
 void Compositor::composite(RenderLoop *renderLoop)
 {
     if (m_backend->checkGraphicsReset()) {
         qCDebug(KWIN_CORE) << "Graphics reset occurred";
 #if KWIN_BUILD_NOTIFICATIONS
         KNotification::event(QStringLiteral("graphicsreset"), i18n("Desktop effects were restarted due to a graphics reset"));
 #endif
         reinitialize();
         return;
     }
 
     Output *output = findOutput(renderLoop);
     OutputLayer *primaryLayer = m_backend->primaryLayer(output);
     fTraceDuration("Paint (", output->name(), ")");
 
     RenderLayer *superLayer = m_superlayers[renderLoop];
     prePaintPass(superLayer);
     superLayer->setOutputLayer(primaryLayer);
 
     SurfaceItem *scanoutCandidate = superLayer->delegate()->scanoutCandidate();
     renderLoop->setFullscreenSurface(scanoutCandidate);
     output->setContentType(scanoutCandidate ? scanoutCandidate->contentType() : ContentType::None);
 
     renderLoop->beginFrame();
     bool directScanout = false;
     if (scanoutCandidate) {
         const auto sublayers = superLayer->sublayers();
         const bool scanoutPossible = std::none_of(sublayers.begin(), sublayers.end(), [](RenderLayer *sublayer) {
             return sublayer->isVisible();
         });
         if (scanoutPossible && !output->directScanoutInhibited()) {
             directScanout = primaryLayer->scanout(scanoutCandidate);
         }
     }
 
     if (!directScanout) {
         QRegion surfaceDamage = primaryLayer->repaints();
         primaryLayer->resetRepaints();
         preparePaintPass(superLayer, &surfaceDamage);
 
         if (auto beginInfo = primaryLayer->beginFrame()) {
             auto &[renderTarget, repaint] = beginInfo.value();
             renderTarget.setDevicePixelRatio(output->scale());
 
             const QRegion bufferDamage = surfaceDamage.united(repaint).intersected(superLayer->rect());
             primaryLayer->aboutToStartPainting(bufferDamage);
 
             paintPass(superLayer, &renderTarget, bufferDamage);
             primaryLayer->endFrame(bufferDamage, surfaceDamage);
         }
     }
 
     postPaintPass(superLayer);
     renderLoop->endFrame();
 
     m_backend->present(output);
 
     // TODO: Put it inside the cursor layer once the cursor layer can be backed by a real output layer.
     if (waylandServer()) {
         const std::chrono::milliseconds frameTime =
             std::chrono::duration_cast<std::chrono::milliseconds>(output->renderLoop()->lastPresentationTimestamp());
 
         if (!Cursors::self()->isCursorHidden()) {
             Cursor *cursor = Cursors::self()->currentCursor();
             if (cursor->geometry().intersects(output->geometry())) {
                 cursor->markAsRendered(frameTime);
             }
         }
     }
 }
 
 void Compositor::prePaintPass(RenderLayer *layer)
 {
     layer->delegate()->prePaint();
     const auto sublayers = layer->sublayers();
     for (RenderLayer *sublayer : sublayers) {
         prePaintPass(sublayer);
     }
 }
 
 void Compositor::postPaintPass(RenderLayer *layer)
 {
     layer->delegate()->postPaint();
     const auto sublayers = layer->sublayers();
     for (RenderLayer *sublayer : sublayers) {
         postPaintPass(sublayer);
     }
 }
 
 void Compositor::preparePaintPass(RenderLayer *layer, QRegion *repaint)
 {
     // TODO: Cull opaque region.
     *repaint += layer->mapToGlobal(layer->repaints() + layer->delegate()->repaints());
     layer->resetRepaints();
     const auto sublayers = layer->sublayers();
     for (RenderLayer *sublayer : sublayers) {
         if (sublayer->isVisible()) {
             preparePaintPass(sublayer, repaint);
         }
     }
 }
 
 void Compositor::paintPass(RenderLayer *layer, RenderTarget *target, const QRegion &region)
 {
     layer->delegate()->paint(target, region);
 
     const auto sublayers = layer->sublayers();
     for (RenderLayer *sublayer : sublayers) {
         if (sublayer->isVisible()) {
             paintPass(sublayer, target, region);
         }
     }
 }
 
 bool Compositor::isActive()
 {
     return m_state == State::On;
 }
 
 bool Compositor::compositingPossible() const
 {
     return true;
 }
 
 QString Compositor::compositingNotPossibleReason() const
 {
     return QString();
 }
 
 bool Compositor::openGLCompositingIsBroken() const
 {
     return false;
 }
 
 void Compositor::createOpenGLSafePoint(OpenGLSafePoint safePoint)
 {
 }
 
 WaylandCompositor::WaylandCompositor(QObject *parent)
     : Compositor(parent)
 {
     connect(kwinApp(), &Application::x11ConnectionAboutToBeDestroyed,
             this, &WaylandCompositor::destroyCompositorSelection);
 }
 
 WaylandCompositor::~WaylandCompositor()
 {
     Q_EMIT aboutToDestroy();
     stop(); // this can't be called in the destructor of Compositor
 }
 
 void WaylandCompositor::toggleCompositing()
 {
     // For the shortcut. Not possible on Wayland because we always composite.
 }
 
 void WaylandCompositor::start()
 {
     if (!Compositor::setupStart()) {
         // Internal setup failed, abort.
         return;
     }
 
     if (Workspace::self()) {
         startupWithWorkspace();
     } else {
         connect(kwinApp(), &Application::workspaceCreated,
                 this, &WaylandCompositor::startupWithWorkspace);
     }
 }
 
 X11Compositor::X11Compositor(QObject *parent)
     : Compositor(parent)
     , m_suspended(options->isUseCompositing() ? NoReasonSuspend : UserSuspend)
 {
     if (qEnvironmentVariableIsSet("KWIN_MAX_FRAMES_TESTED")) {
         m_framesToTestForSafety = qEnvironmentVariableIntValue("KWIN_MAX_FRAMES_TESTED");
     }
 }
 
 X11Compositor::~X11Compositor()
 {
     Q_EMIT aboutToDestroy();
     if (m_openGLFreezeProtectionThread) {
         m_openGLFreezeProtectionThread->quit();
         m_openGLFreezeProtectionThread->wait();
     }
     stop(); // this can't be called in the destructor of Compositor
 }
 
 X11SyncManager *X11Compositor::syncManager() const
 {
     return m_syncManager.get();
 }
 
 void X11Compositor::toggleCompositing()
 {
     if (m_suspended) {
         // Direct user call; clear all bits.
         resume(AllReasonSuspend);
     } else {
         // But only set the user one (sufficient to suspend).
         suspend(UserSuspend);
     }
 }
 
 void X11Compositor::reinitialize()
 {
     // Resume compositing if suspended.
     m_suspended = NoReasonSuspend;
     Compositor::reinitialize();
 }
 
 void X11Compositor::configChanged()
 {
     if (m_suspended) {
         stop();
         return;
     }
     Compositor::configChanged();
 }
 
 void X11Compositor::suspend(X11Compositor::SuspendReason reason)
 {
     Q_ASSERT(reason != NoReasonSuspend);
     m_suspended |= reason;
 
     if (reason & ScriptSuspend) {
         // When disabled show a shortcut how the user can get back compositing.
         const auto shortcuts = KGlobalAccel::self()->shortcut(
             workspace()->findChild<QAction *>(QStringLiteral("Suspend Compositing")));
         if (!shortcuts.isEmpty()) {
             // Display notification only if there is the shortcut.
             const QString message =
                 i18n("Desktop effects have been suspended by another application.<br/>"
                      "You can resume using the '%1' shortcut.",
                      shortcuts.first().toString(QKeySequence::NativeText));
 #if KWIN_BUILD_NOTIFICATIONS
             KNotification::event(QStringLiteral("compositingsuspendeddbus"), message);
 #endif
         }
     }
     stop();
 }
 
 void X11Compositor::resume(X11Compositor::SuspendReason reason)
 {
     Q_ASSERT(reason != NoReasonSuspend);
     m_suspended &= ~reason;
     start();
 }
 
 void X11Compositor::start()
 {
     if (m_suspended) {
         QStringList reasons;
         if (m_suspended & UserSuspend) {
             reasons << QStringLiteral("Disabled by User");
         }
         if (m_suspended & BlockRuleSuspend) {
             reasons << QStringLiteral("Disabled by Window");
         }
         if (m_suspended & ScriptSuspend) {
             reasons << QStringLiteral("Disabled by Script");
         }
         qCInfo(KWIN_CORE) << "Compositing is suspended, reason:" << reasons;
         return;
     } else if (!compositingPossible()) {
         qCWarning(KWIN_CORE) << "Compositing is not possible";
         return;
     }
     if (!Compositor::setupStart()) {
         // Internal setup failed, abort.
         return;
     }
     startupWithWorkspace();
     m_syncManager.reset(X11SyncManager::create());
 }
 
 void X11Compositor::stop()
 {
     m_syncManager.reset();
     Compositor::stop();
 }
 
 void X11Compositor::composite(RenderLoop *renderLoop)
 {
     if (backend()->overlayWindow() && !isOverlayWindowVisible()) {
         // Return since nothing is visible.
         return;
     }
 
     QList<Window *> windows = workspace()->stackingOrder();
     QList<SurfaceItemX11 *> dirtyItems;
 
     // Reset the damage state of each window and fetch the damage region
     // without waiting for a reply
     for (Window *window : std::as_const(windows)) {
         SurfaceItemX11 *surfaceItem = static_cast<SurfaceItemX11 *>(window->surfaceItem());
         if (surfaceItem->fetchDamage()) {
             dirtyItems.append(surfaceItem);
         }
     }
 
     if (dirtyItems.count() > 0) {
         if (m_syncManager) {
             m_syncManager->triggerFence();
         }
         xcb_flush(kwinApp()->x11Connection());
     }
 
     // Get the replies
     for (SurfaceItemX11 *item : std::as_const(dirtyItems)) {
         item->waitForDamage();
     }
 
     if (m_framesToTestForSafety > 0 && (backend()->compositingType() & OpenGLCompositing)) {
         createOpenGLSafePoint(OpenGLSafePoint::PreFrame);
     }
 
     Compositor::composite(renderLoop);
 
     if (m_syncManager) {
         if (!m_syncManager->endFrame()) {
             qCDebug(KWIN_CORE) << "Aborting explicit synchronization with the X command stream.";
             qCDebug(KWIN_CORE) << "Future frames will be rendered unsynchronized.";
             m_syncManager.reset();
         }
     }
 
     if (m_framesToTestForSafety > 0) {
         if (backend()->compositingType() & OpenGLCompositing) {
             createOpenGLSafePoint(OpenGLSafePoint::PostFrame);
         }
         m_framesToTestForSafety--;
         if (m_framesToTestForSafety == 0 && (backend()->compositingType() & OpenGLCompositing)) {
             createOpenGLSafePoint(OpenGLSafePoint::PostLastGuardedFrame);
         }
     }
 }
 
 bool X11Compositor::checkForOverlayWindow(WId w) const
 {
     if (!backend()) {
         // No backend, so it cannot be the overlay window.
         return false;
     }
     if (!backend()->overlayWindow()) {
         // No overlay window, it cannot be the overlay.
         return false;
     }
     // Compare the window ID's.
     return w == backend()->overlayWindow()->window();
 }
 
 bool X11Compositor::isOverlayWindowVisible() const
 {
     if (!backend()) {
         return false;
     }
     if (!backend()->overlayWindow()) {
         return false;
     }
     return backend()->overlayWindow()->isVisible();
 }
 
 void X11Compositor::updateClientCompositeBlocking(X11Window *c)
 {
     if (c) {
         if (c->isBlockingCompositing()) {
             // Do NOT attempt to call suspend(true) from within the eventchain!
             if (!(m_suspended & BlockRuleSuspend)) {
                 QMetaObject::invokeMethod(
                     this, [this]() {
                         suspend(BlockRuleSuspend);
                     },
                     Qt::QueuedConnection);
             }
         }
     } else if (m_suspended & BlockRuleSuspend) {
         // If !c we just check if we can resume in case a blocking client was lost.
         bool shouldResume = true;
 
         for (auto it = Workspace::self()->clientList().constBegin();
              it != Workspace::self()->clientList().constEnd(); ++it) {
             if ((*it)->isBlockingCompositing()) {
                 shouldResume = false;
                 break;
             }
         }
         if (shouldResume) {
             // Do NOT attempt to call suspend(false) from within the eventchain!
             QMetaObject::invokeMethod(
                 this, [this]() {
                     resume(BlockRuleSuspend);
                 },
                 Qt::QueuedConnection);
         }
     }
 }
 
 X11Compositor *X11Compositor::self()
 {
     return qobject_cast<X11Compositor *>(Compositor::self());
 }
 
 bool X11Compositor::openGLCompositingIsBroken() const
 {
     auto timestamp = KConfigGroup(kwinApp()->config(), "Compositing").readEntry(QLatin1String("LastFailureTimestamp"), 0);
     if (timestamp > 0) {
         if (QDateTime::currentSecsSinceEpoch() - timestamp < 60) {
             return true;
         }
     }
 
     return false;
 }
 
 QString X11Compositor::compositingNotPossibleReason() const
 {
     // first off, check whether we figured that we'll crash on detection because of a buggy driver
     KConfigGroup gl_workaround_group(kwinApp()->config(), "Compositing");
     if (gl_workaround_group.readEntry("Backend", "OpenGL") == QLatin1String("OpenGL") && openGLCompositingIsBroken()) {
         return i18n("<b>OpenGL compositing (the default) has crashed KWin in the past.</b><br>"
                     "This was most likely due to a driver bug."
                     "<p>If you think that you have meanwhile upgraded to a stable driver,<br>"
                     "you can reset this protection but <b>be aware that this might result in an immediate crash!</b></p>");
     }
 
     if (!Xcb::Extensions::self()->isCompositeAvailable() || !Xcb::Extensions::self()->isDamageAvailable()) {
         return i18n("Required X extensions (XComposite and XDamage) are not available.");
     }
     if (!Xcb::Extensions::self()->hasGlx()) {
         return i18n("GLX/OpenGL is not available.");
     }
     return QString();
 }
 
 bool X11Compositor::compositingPossible() const
 {
     // first off, check whether we figured that we'll crash on detection because of a buggy driver
     KConfigGroup gl_workaround_group(kwinApp()->config(), "Compositing");
     if (gl_workaround_group.readEntry("Backend", "OpenGL") == QLatin1String("OpenGL") && openGLCompositingIsBroken()) {
         qCWarning(KWIN_CORE) << "Compositing disabled: video driver seems unstable. If you think it's a false positive, please try again in a few minutes.";
         return false;
     }
 
     if (!Xcb::Extensions::self()->isCompositeAvailable()) {
         qCWarning(KWIN_CORE) << "Compositing disabled: no composite extension available";
         return false;
     }
     if (!Xcb::Extensions::self()->isDamageAvailable()) {
         qCWarning(KWIN_CORE) << "Compositing disabled: no damage extension available";
         return false;
     }
     if (Xcb::Extensions::self()->hasGlx()) {
         return true;
     }
     if (QOpenGLContext::openGLModuleType() == QOpenGLContext::LibGLES) {
         return true;
     } else if (qstrcmp(qgetenv("KWIN_COMPOSE"), "O2ES") == 0) {
         return true;
     }
     qCWarning(KWIN_CORE) << "Compositing disabled: no OpenGL support";
     return false;
 }
 
 void X11Compositor::createOpenGLSafePoint(OpenGLSafePoint safePoint)
 {
     auto group = KConfigGroup(kwinApp()->config(), "Compositing");
     switch (safePoint) {
     case OpenGLSafePoint::PreInit:
         // Explicitly write the failure timestamp so that if we crash during
         // OpenGL init, we know we should not try again.
         group.writeEntry(QLatin1String("LastFailureTimestamp"), QDateTime::currentSecsSinceEpoch());
         group.sync();
         // Deliberately continue with PreFrame
         Q_FALLTHROUGH();
     case OpenGLSafePoint::PreFrame:
         if (m_openGLFreezeProtectionThread == nullptr) {
             Q_ASSERT(m_openGLFreezeProtection == nullptr);
             m_openGLFreezeProtectionThread = std::make_unique<QThread>();
             m_openGLFreezeProtectionThread->setObjectName("FreezeDetector");
             m_openGLFreezeProtectionThread->start();
             m_openGLFreezeProtection = std::make_unique<QTimer>();
             m_openGLFreezeProtection->setInterval(15000);
             m_openGLFreezeProtection->setSingleShot(true);
             m_openGLFreezeProtection->start();
             const QString configName = kwinApp()->config()->name();
             m_openGLFreezeProtection->moveToThread(m_openGLFreezeProtectionThread.get());
             connect(
                 m_openGLFreezeProtection.get(), &QTimer::timeout, m_openGLFreezeProtection.get(),
                 [configName] {
                     auto group = KConfigGroup(KSharedConfig::openConfig(configName), "Compositing");
                     group.writeEntry(QLatin1String("LastFailureTimestamp"), QDateTime::currentSecsSinceEpoch());
                     group.sync();
                     KCrash::setDrKonqiEnabled(false);
                     qFatal("Freeze in OpenGL initialization detected");
                 },
                 Qt::DirectConnection);
         } else {
             Q_ASSERT(m_openGLFreezeProtection);
             QMetaObject::invokeMethod(m_openGLFreezeProtection.get(), QOverload<>::of(&QTimer::start), Qt::QueuedConnection);
         }
         break;
     case OpenGLSafePoint::PostInit:
         group.deleteEntry(QLatin1String("LastFailureTimestamp"));
         group.sync();
         // Deliberately continue with PostFrame
         Q_FALLTHROUGH();
     case OpenGLSafePoint::PostFrame:
         QMetaObject::invokeMethod(m_openGLFreezeProtection.get(), &QTimer::stop, Qt::QueuedConnection);
         break;
     case OpenGLSafePoint::PostLastGuardedFrame:
         m_openGLFreezeProtectionThread->quit();
         m_openGLFreezeProtectionThread->wait();
         m_openGLFreezeProtectionThread.reset();
         m_openGLFreezeProtection.reset();
         break;
     }
 }
 
 }
 
 // included for CompositorSelectionOwner
 #include "composite.moc"