Advance Wayland and KDE package bring-up

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

local/recipes/kde/kwin/source/src/focuschain.h

@@ -0,0 +1,238 @@
+/*
+    KWin - the KDE window manager
+    This file is part of the KDE project.
+
+    SPDX-FileCopyrightText: 2012 Martin Gräßlin <mgraesslin@kde.org>
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+#pragma once
+// KWin
+#include "effect/globals.h"
+// Qt
+#include <QHash>
+#include <QObject>
+
+namespace KWin
+{
+// forward declarations
+class Window;
+class Output;
+class VirtualDesktop;
+
+/**
+ * @brief Singleton class to handle the various focus chains.
+ *
+ * A focus chain is a list of Windows containing information on which Window should be activated.
+ *
+ * Internally this FocusChain holds multiple independent chains. There is one chain of most recently
+ * used Windows which is primarily used by TabBox to build up the list of Windows for navigation.
+ * The chains are organized as a normal QList of Windows with the most recently used Window being the
+ * last item of the list, that is a LIFO like structure.
+ *
+ * In addition there is one chain for each virtual desktop which is used to determine which Window
+ * should get activated when the user switches to another virtual desktop.
+ *
+ * Furthermore this class contains various helper methods for the two different kind of chains.
+ */
+class FocusChain : public QObject
+{
+    Q_OBJECT
+public:
+    enum Change {
+        MakeFirst,
+        MakeLast,
+        Update,
+        MakeFirstMinimized = MakeFirst
+    };
+    explicit FocusChain() = default;
+
+    /**
+     * @brief Updates the position of the @p window according to the requested @p change in the
+     * focus chain.
+     *
+     * This method affects both the most recently used focus chain and the per virtual desktop focus
+     * chain.
+     *
+     * In case the window does no longer want to get focus, it is removed from all chains. In case
+     * the window is on all virtual desktops it is ensured that it is present in each of the virtual
+     * desktops focus chain. In case it's on exactly one virtual desktop it is ensured that it is only
+     * in the focus chain for that virtual desktop.
+     *
+     * Depending on @p change the Window is inserted at different positions in the focus chain. In case
+     * of @c MakeFirst it is moved to the first position of the chain, in case of
+     * @c MakeLast it is moved to the last position of the chain. In all other cases it
+     * depends on whether the @p window is the currently active Window. If it is the active Window it
+     * becomes the first Window in the chain, otherwise it is inserted at the second position that is
+     * directly after the currently active Window.
+     *
+     * @param window The Window which should be moved inside the chains.
+     * @param change Where to move the Window
+     * @return void
+     */
+    void update(Window *window, Change change);
+    /**
+     * @brief Moves @p window behind the @p reference Window in all focus chains.
+     *
+     * @param window The Window to move in the chains
+     * @param reference The Window behind which the @p window should be moved
+     * @return void
+     */
+    void moveAfterWindow(Window *window, Window *reference);
+    /**
+     * @brief Moves @p window in front of the @p reference Window in all focus chains.
+     *
+     * @param window The Window to move in the chains
+     * @param reference The Window in front of which the @p window should be moved
+     * @return void
+     */
+    void moveBeforeWindow(Window *window, Window *reference);
+    /**
+     * @brief Finds the best Window to become the new active Window in the focus chain for the given
+     * virtual @p desktop.
+     *
+     * In case that separate screen focus is used only Windows on the current screen are considered.
+     * If no Window for activation is found @c null is returned.
+     *
+     * @param desktop The virtual desktop to look for a Window for activation
+     * @return :X11Window *The Window which could be activated or @c null if there is none.
+     */
+    Window *getForActivation(VirtualDesktop *desktop) const;
+    /**
+     * @brief Finds the best Window to become the new active Window in the focus chain for the given
+     * virtual @p desktop on the given @p screen.
+     *
+     * This method makes only sense to use if separate screen focus is used. If separate screen focus
+     * is disabled the @p screen is ignored.
+     * If no Window for activation is found @c null is returned.
+     *
+     * @param desktop The virtual desktop to look for a Window for activation
+     * @param output The screen to constrain the search on with separate screen focus
+     * @return :X11Window *The Window which could be activated or @c null if there is none.
+     */
+    Window *getForActivation(VirtualDesktop *desktop, Output *output) const;
+
+    /**
+     * @brief Checks whether the most recently used focus chain contains the given @p window.
+     *
+     * Does not consider the per-desktop focus chains.
+     * @param window The Window to look for.
+     * @return bool @c true if the most recently used focus chain contains @p window, @c false otherwise.
+     */
+    bool contains(Window *window) const;
+    /**
+     * @brief Checks whether the focus chain for the given @p desktop contains the given @p window.
+     *
+     * Does not consider the most recently used focus chain.
+     *
+     * @param window The Window to look for.
+     * @param desktop The virtual desktop whose focus chain should be used
+     * @return bool @c true if the focus chain for @p desktop contains @p window, @c false otherwise.
+     */
+    bool contains(Window *window, VirtualDesktop *desktop) const;
+    /**
+     * @brief Queries the most recently used focus chain for the next Window after the given
+     * @p reference Window.
+     *
+     * The navigation wraps around the borders of the chain. That is if the @p reference Window is
+     * the last item of the focus chain, the first Window will be returned.
+     *
+     * If the @p reference Window cannot be found in the focus chain, the first element of the focus
+     * chain is returned.
+     *
+     * @param reference The start point in the focus chain to search
+     * @return :X11Window *The relatively next Window in the most recently used chain.
+     */
+    Window *nextMostRecentlyUsed(Window *reference) const;
+    /**
+     * @brief Queries the focus chain for @p desktop for the next Window in relation to the given
+     * @p reference Window.
+     *
+     * The method finds the first usable Window which is not the @p reference Window. If no Window
+     * can be found @c null is returned
+     *
+     * @param reference The reference Window which should not be returned
+     * @param desktop The virtual desktop whose focus chain should be used
+     * @return :X11Window *The next usable Window or @c null if none can be found.
+     */
+    Window *nextForDesktop(Window *reference, VirtualDesktop *desktop) const;
+    /**
+     * @brief Returns the first Window in the most recently used focus chain. First Window in this
+     * case means really the first Window in the chain and not the most recently used Window.
+     *
+     * @return :X11Window *The first Window in the most recently used chain.
+     */
+    Window *firstMostRecentlyUsed() const;
+
+    bool isUsableFocusCandidate(Window *window, Window *prev) const;
+
+public Q_SLOTS:
+    /**
+     * @brief Removes @p window from all focus chains.
+     *
+     * @param window The Window to remove from all focus chains.
+     * @return void
+     */
+    void remove(KWin::Window *window);
+    void setSeparateScreenFocus(bool enabled);
+    void setActiveWindow(KWin::Window *window);
+    void setCurrentDesktop(VirtualDesktop *desktop);
+    void addDesktop(VirtualDesktop *desktop);
+    void removeDesktop(VirtualDesktop *desktop);
+
+private:
+    using Chain = QList<Window *>;
+    /**
+     * @brief Makes @p window the first Window in the given focus @p chain.
+     *
+     * This means the existing position of @p window is dropped and @p window is appended to the
+     * @p chain which makes it the first item.
+     *
+     * @param window The Window to become the first in @p chain
+     * @param chain The focus chain to operate on
+     * @return void
+     */
+    void makeFirstInChain(Window *window, Chain &chain);
+    /**
+     * @brief Makes @p window the last Window in the given focus @p chain.
+     *
+     * This means the existing position of @p window is dropped and @p window is prepended to the
+     * @p chain which makes it the last item.
+     *
+     * @param window The Window to become the last in @p chain
+     * @param chain The focus chain to operate on
+     * @return void
+     */
+    void makeLastInChain(Window *window, Chain &chain);
+    void moveAfterWindowInChain(Window *window, Window *reference, Chain &chain);
+    void moveBeforeWindowInChain(Window *window, Window *reference, Chain &chain);
+    void updateWindowInChain(Window *window, Change change, Chain &chain);
+    void insertWindowIntoChain(Window *window, Chain &chain);
+    Chain m_mostRecentlyUsed;
+    QHash<VirtualDesktop *, Chain> m_desktopFocusChains;
+    bool m_separateScreenFocus = false;
+    Window *m_activeWindow = nullptr;
+    VirtualDesktop *m_currentDesktop = nullptr;
+};
+
+inline bool FocusChain::contains(Window *window) const
+{
+    return m_mostRecentlyUsed.contains(window);
+}
+
+inline void FocusChain::setSeparateScreenFocus(bool enabled)
+{
+    m_separateScreenFocus = enabled;
+}
+
+inline void FocusChain::setActiveWindow(Window *window)
+{
+    m_activeWindow = window;
+}
+
+inline void FocusChain::setCurrentDesktop(VirtualDesktop *desktop)
+{
+    m_currentDesktop = desktop;
+}
+
+} // namespace