File indexing completed on 2024-04-28 05:30:13

 /*
     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 "compositor_x11.h"
 #include "core/outputbackend.h"
 #include "core/overlaywindow.h"
 #include "core/renderbackend.h"
 #include "core/renderlayer.h"
 #include "effect/effecthandler.h"
 #include "opengl/glplatform.h"
 #include "options.h"
 #include "platformsupport/scenes/opengl/openglbackend.h"
 #include "scene/surfaceitem_x11.h"
 #include "scene/workspacescene_opengl.h"
 #include "utils/common.h"
 #include "utils/xcbutils.h"
 #include "window.h"
 #include "workspace.h"
 #include "x11syncmanager.h"
 
 #include <KCrash>
 #include <KGlobalAccel>
 #include <KLocalizedString>
 #include <KSelectionOwner>
 
 #include <QAction>
 #include <QOpenGLContext>
 #include <QThread>
 
 Q_DECLARE_METATYPE(KWin::X11Compositor::SuspendReason)
 
 namespace KWin
 {
 
 class X11CompositorSelectionOwner : public KSelectionOwner
 {
     Q_OBJECT
 
 public:
     X11CompositorSelectionOwner(const char *selection)
         : KSelectionOwner(selection, kwinApp()->x11Connection(), kwinApp()->x11RootWindow())
         , m_owning(false)
     {
         connect(this, &X11CompositorSelectionOwner::lostOwnership, this, [this]() {
             m_owning = false;
         });
     }
     bool owning() const
     {
         return m_owning;
     }
     void setOwning(bool own)
     {
         m_owning = own;
     }
 
 private:
     bool m_owning;
 };
 
 X11Compositor *X11Compositor::create(QObject *parent)
 {
     Q_ASSERT(!s_compositor);
     auto *compositor = new X11Compositor(parent);
     s_compositor = compositor;
     return compositor;
 }
 
 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");
     }
 
     connect(options, &Options::configChanged, this, [this]() {
         if (m_suspended) {
             stop();
         } else {
             reinitialize();
         }
     });
 
     m_releaseSelectionTimer.setSingleShot(true);
     m_releaseSelectionTimer.setInterval(2000);
     connect(&m_releaseSelectionTimer, &QTimer::timeout, this, &X11Compositor::releaseCompositorSelection);
 
     QAction *toggleAction = new QAction(this);
     toggleAction->setProperty("componentName", QStringLiteral("kwin"));
     toggleAction->setObjectName("Suspend Compositing");
     toggleAction->setText(i18n("Suspend Compositing"));
     KGlobalAccel::self()->setDefaultShortcut(toggleAction, QList<QKeySequence>() << (Qt::SHIFT | Qt::ALT | Qt::Key_F12));
     KGlobalAccel::self()->setShortcut(toggleAction, QList<QKeySequence>() << (Qt::SHIFT | Qt::ALT | Qt::Key_F12));
     connect(toggleAction, &QAction::triggered, this, &X11Compositor::toggle);
 }
 
 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
     destroyCompositorSelection();
 }
 
 X11SyncManager *X11Compositor::syncManager() const
 {
     return m_syncManager.get();
 }
 
 void X11Compositor::toggle()
 {
     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;
     m_inhibitors.clear();
     Compositor::reinitialize();
 }
 
 void X11Compositor::suspend(X11Compositor::SuspendReason reason)
 {
     Q_ASSERT(reason != NoReasonSuspend);
     m_suspended |= reason;
     stop();
 }
 
 void X11Compositor::resume(X11Compositor::SuspendReason reason)
 {
     Q_ASSERT(reason != NoReasonSuspend);
     m_suspended &= ~reason;
     if (reason & BlockRuleSuspend) {
         m_inhibitors.clear();
     }
     start();
 }
 
 void X11Compositor::destroyCompositorSelection()
 {
     m_selectionOwner.reset();
 }
 
 void X11Compositor::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;
     }
 }
 
 bool X11Compositor::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 (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_backend = std::move(backend);
 
     // set strict binding
     if (options->isGlStrictBindingFollowsDriver()) {
         options->setGlStrictBinding(!GLPlatform::instance()->supports(GLFeature::LooseBinding));
     }
 
     qCDebug(KWIN_CORE) << "OpenGL compositing has been successfully initialized";
     return true;
 }
 
 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");
         }
         qCInfo(KWIN_CORE) << "Compositing is suspended, reason:" << reasons;
         return;
     } else if (!compositingPossible()) {
         qCWarning(KWIN_CORE) << "Compositing is not possible";
         return;
     }
 
     if (kwinApp()->isTerminating()) {
         return;
     }
     if (m_state != State::Off) {
         return;
     }
 
     Q_EMIT aboutToToggleCompositing();
     m_state = State::Starting;
 
     // Claim special _NET_WM_CM_S0 selection and redirect child windows of the root window.
     if (!m_selectionOwner) {
         m_selectionOwner = std::make_unique<X11CompositorSelectionOwner>("_NET_WM_CM_S0");
         connect(m_selectionOwner.get(), &X11CompositorSelectionOwner::lostOwnership, this, &X11Compositor::stop);
     }
     if (!m_selectionOwner->owning()) {
         // Force claim ownership.
         m_selectionOwner->claim(true);
         m_selectionOwner->setOwning(true);
     }
 
     xcb_composite_redirect_subwindows(kwinApp()->x11Connection(),
                                       kwinApp()->x11RootWindow(),
                                       XCB_COMPOSITE_REDIRECT_MANUAL);
 
     // Decide what compositing types can be used.
     QList<CompositingType> candidateCompositors = kwinApp()->outputBackend()->supportedCompositors();
     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) << "QPainter compositing is unsupported on X11";
             break;
         case NoCompositing:
             qCDebug(KWIN_CORE) << "Starting without compositing...";
             stop = true;
             break;
         }
 
         if (stop) {
             break;
         } else if (qEnvironmentVariableIsSet("KWIN_COMPOSE")) {
             qCCritical(KWIN_CORE) << "Could not fulfill the requested compositing mode in KWIN_COMPOSE:" << type << ". Exiting.";
             qApp->quit();
         }
     }
 
     if (!m_backend) {
         m_state = State::Off;
 
         xcb_composite_unredirect_subwindows(kwinApp()->x11Connection(),
                                             kwinApp()->x11RootWindow(),
                                             XCB_COMPOSITE_REDIRECT_MANUAL);
         if (m_selectionOwner) {
             m_selectionOwner->setOwning(false);
             m_selectionOwner->release();
         }
         return;
     }
 
     Q_EMIT sceneCreated();
 
     kwinApp()->setX11CompositeWindow(backend()->overlayWindow()->window());
 
     auto workspaceLayer = new RenderLayer(workspace()->outputs()[0]->renderLoop());
     workspaceLayer->setDelegate(std::make_unique<SceneDelegate>(m_scene.get(), nullptr));
     workspaceLayer->setGeometry(workspace()->geometry());
     connect(workspace(), &Workspace::geometryChanged, workspaceLayer, [workspaceLayer]() {
         workspaceLayer->setGeometry(workspace()->geometry());
     });
     addSuperLayer(workspaceLayer);
 
     m_state = State::On;
 
     const auto windows = workspace()->windows();
     for (Window *window : windows) {
         window->setupCompositing();
     }
 
     // Sets also the 'effects' pointer.
     kwinApp()->createEffectsHandler(this, m_scene.get());
 
     m_syncManager.reset(X11SyncManager::create());
     if (m_releaseSelectionTimer.isActive()) {
         m_releaseSelectionTimer.stop();
     }
 
     Q_EMIT compositingToggled(true);
 }
 
 void X11Compositor::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()) {
         const auto windows = workspace()->windows();
         for (Window *window : windows) {
             window->finishCompositing();
         }
         xcb_composite_unredirect_subwindows(kwinApp()->x11Connection(),
                                             kwinApp()->x11RootWindow(),
                                             XCB_COMPOSITE_REDIRECT_MANUAL);
     }
 
     if (m_backend->compositingType() == OpenGLCompositing) {
         // some layers need a context current for destruction
         static_cast<OpenGLBackend *>(m_backend.get())->makeCurrent();
     }
 
     const auto superlayers = m_superlayers;
     for (auto it = superlayers.begin(); it != superlayers.end(); ++it) {
         removeSuperLayer(*it);
     }
 
     m_syncManager.reset();
     m_scene.reset();
     m_backend.reset();
 
     kwinApp()->setX11CompositeWindow(XCB_WINDOW_NONE);
 
     m_state = State::Off;
     Q_EMIT compositingToggled(false);
 }
 
 void X11Compositor::composite(RenderLoop *renderLoop)
 {
     if (backend()->overlayWindow() && !backend()->overlayWindow()->isVisible()) {
         // 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);
         }
     }
 }
 
 void X11Compositor::inhibit(Window *window)
 {
     m_inhibitors.insert(window);
     // Do NOT attempt to call suspend(true) from within the eventchain!
     if (!(m_suspended & BlockRuleSuspend)) {
         QMetaObject::invokeMethod(
             this, [this]() {
                 suspend(BlockRuleSuspend);
             },
             Qt::QueuedConnection);
     }
 }
 
 void X11Compositor::uninhibit(Window *window)
 {
     if (!m_inhibitors.remove(window)) {
         return;
     }
     if (m_suspended & BlockRuleSuspend) {
         if (m_inhibitors.isEmpty()) {
             // 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(), QStringLiteral("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(), QStringLiteral("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(), QStringLiteral("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(), QStringLiteral("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), QStringLiteral("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;
     }
 }
 
 } // namespace KWin
 
 #include "compositor_x11.moc"
 #include "moc_compositor_x11.cpp"