patches.js

/* eslint-disable no-undef */
/* eslint-disable no-invalid-this */
import Clutter from 'gi://Clutter';
import Gio from 'gi://Gio';
import GLib from 'gi://GLib';
import Meta from 'gi://Meta';
import Shell from 'gi://Shell';
import St from 'gi://St';

import * as Main from 'resource:///org/gnome/shell/ui/main.js';
import * as Workspace from 'resource:///org/gnome/shell/ui/workspace.js';
import * as WorkspaceThumbnail from 'resource:///org/gnome/shell/ui/workspaceThumbnail.js';
import * as WorkspaceAnimation from 'resource:///org/gnome/shell/ui/workspaceAnimation.js';
import * as AltTab from 'resource:///org/gnome/shell/ui/altTab.js';
import * as WindowManager from 'resource:///org/gnome/shell/ui/windowManager.js';
import * as WindowPreview from 'resource:///org/gnome/shell/ui/windowPreview.js';
import * as Screenshot from 'resource:///org/gnome/shell/ui/screenshot.js';

import { Utils, Tiling, Scratch, Settings, OverviewLayout } from './imports.js';

/**
  Some of Gnome Shell's default behavior is really sub-optimal when using
  paperWM. Other features are simply not possible to implement without monkey
  patching. This is a collection of monkey patches and preferences which works
  around these problems and facilitates new features.
 */

let savedProps, signals;
let gsettings, mutterSettings;
let pillSwipeTimer;
export function enable(extension) {
    savedProps = new Map();
    gsettings = extension.getSettings();

    // save the last display server used
    gsettings.set_string(
        'last-used-display-server',
        Meta.is_wayland_compositor() ? "Wayland" : "Xorg"
    );

    mutterSettings = new Gio.Settings({ schema_id: 'org.gnome.mutter' });
    signals = new Utils.Signals();
    setupSwipeTrackers();
    setupOverrides();
    enableOverrides();
    setupRuntimeDisables();
    setupActions();
}

export function disable() {
    disableOverrides();
    restoreRuntimeDisables();
    actions.forEach(a => global.stage.add_action(a));
    actions = null;

    signals.destroy();
    signals = null;

    savedProps = null;
    swipeTrackers = null;
    gsettings = null;
    mutterSettings = null;
    Utils.timeout_remove(pillSwipeTimer);
    pillSwipeTimer = null;
    actions = null;
}

export function registerOverrideProp(obj, name, override, warn = true) {
    if (!obj)
        return;

    // check if prop exists
    const exists = obj?.[name];
    if (!exists && warn) {
        console.warn(`#PaperWM: attempt to override prop for '${name}' failed: is null or undefined`);
    }

    let saved = getSavedProp(obj, name) ?? obj[name];
    let props = savedProps.get(obj);
    if (!props) {
        props = {};
        savedProps.set(obj, props);
    }
    props[name] = {
        saved,
        override,
    };
}

export function registerOverridePrototype(obj, name, override) {
    if (!obj)
        return;

    // check if method for prototype exists
    const exists = obj?.prototype?.[name];
    if (!exists) {
        console.warn(`#PaperWM: attempt to override prototype for '${name}' failed: is null or undefined`);
    }

    registerOverrideProp(obj.prototype, name, override);
}

export function makeFallback(obj, method, ...args) {
    let fallback = getSavedPrototype(obj, method);
    return fallback.bind(...args);
}

export function overrideWithFallback(obj, method, body) {
    registerOverridePrototype(
        obj, method, function(...args) {
            let fallback = makeFallback(obj, method, this, ...args);
            body(fallback, this, ...args);
        }
    );
}

export function getSavedProp(obj, name) {
    let props = savedProps.get(obj);
    if (!props)
        return undefined;
    let prop = props[name];
    if (!prop)
        return undefined;
    return prop.saved;
}

export function getSavedPrototype(obj, name) {
    return getSavedProp(obj.prototype, name);
}

export function disableOverride(obj, name) {
    obj[name] = getSavedProp(obj, name);
}

export function enableOverride(obj, name) {
    let props = savedProps.get(obj);
    let override = props[name].override;
    if (override !== undefined) {
        obj[name] = override;
    }
}

/**
 * Sets up PaperWM overrides (needed for operations).  These overrides are registered and restored
 * on PaperWM disable.
 */
export function setupOverrides() {
    registerOverridePrototype(WorkspaceAnimation.WorkspaceAnimationController, 'animateSwitch',
        // WorkspaceAnimation.WorkspaceAnimationController.animateSwitch
        // Disable the workspace switching animation in Gnome 40+
        function (_from, _to, _direction, onComplete) {
            // ensure swipeTrackers are disabled after this
            const reset = () => {
                // gnome windows switch animation time = 250, do that plus a little more
                pillSwipeTimer = GLib.timeout_add(GLib.PRIORITY_DEFAULT, 300, () => {
                    swipeTrackers.forEach(t => {
                        t.enabled = false;
                    });
                    pillSwipeTimer = null;
                    return false; // on return false destroys timeout
                });
            };

            if (Tiling.inPreview) {
                onComplete();
                reset();
                return;
            }

            // if using PaperWM workspace switch animation, just do complete here
            if (!Tiling.spaces.space_defaultAnimation) {
                onComplete();
                reset();
                return;
            }

            // if switching to a paperwm space that is already shown on a monitor
            // from / to are workspace indices
            const toSpace = Tiling.spaces.spaceOfIndex(_to);

            const spaces = Array.from(Tiling.spaces.monitors.values());
            const toOnMonitor = spaces.some(space => space === toSpace);
            if (toOnMonitor) {
                onComplete();
                reset();
                return;
            }

            // standard gnome switch animation
            const saved = getSavedPrototype(WorkspaceAnimation.WorkspaceAnimationController, 'animateSwitch');
            saved.call(this, _from, _to, _direction, onComplete);
            reset();
        });

    registerOverridePrototype(WorkspaceAnimation.WorkspaceAnimationController, '_prepareWorkspaceSwitch',
        function (workspaceIndices) {
            const saved = getSavedPrototype(WorkspaceAnimation.WorkspaceAnimationController, '_prepareWorkspaceSwitch');
            // hide selection during workspace switch
            Tiling.spaces.forEach(s => s.hideSelection());
            saved.call(this, workspaceIndices);
        });

    registerOverridePrototype(WorkspaceAnimation.WorkspaceAnimationController, '_finishWorkspaceSwitch',
        function (switchData) {
            const saved = getSavedPrototype(WorkspaceAnimation.WorkspaceAnimationController,
                '_finishWorkspaceSwitch');
            // ensure selection is shown after workspaces swtching
            Tiling.spaces.forEach(s => s.showSelection());
            saved.call(this, switchData);
        });

    registerOverrideProp(Main.wm._workspaceTracker, '_checkWorkspaces', _checkWorkspaces);

    if (WindowManager.TouchpadWorkspaceSwitchAction) // disable 4-finger swipe
        registerOverridePrototype(WindowManager.TouchpadWorkspaceSwitchAction, '_checkActivated', () => false);

    // disable swipe gesture trackers
    swipeTrackers.forEach(t => {
        registerOverrideProp(t, "enabled", false, false);
    });

    /**
     * Used on overview layout.  UnalignedLayoutStrategy is not exported in Gnome 45, and hence
     * we need to override this function and call PaperWM customised UnalignedLayoutStrategy found
     * in overlayout.js.
     */
    registerOverridePrototype(Workspace.WorkspaceLayout, '_createBestLayout', function(area) {
        const [rowSpacing, columnSpacing] =
        this._adjustSpacingAndPadding(this._spacing, this._spacing, null);

        // We look for the largest scale that allows us to fit the
        // largest row/tallest column on the workspace.
        this._layoutStrategy = new OverviewLayout.UnalignedLayoutStrategy({
            monitor: Main.layoutManager.monitors[this._monitorIndex],
            rowSpacing,
            columnSpacing,
        });

        let lastLayout = null;
        let lastNumColumns = -1;
        let lastScale = 0;
        let lastSpace = 0;

        for (let numRows = 1; ; numRows++) {
            const numColumns = Math.ceil(this._sortedWindows.length / numRows);

            // If adding a new row does not change column count just stop
            // (for instance: 9 windows, with 3 rows -> 3 columns, 4 rows ->
            // 3 columns as well => just use 3 rows then)
            if (numColumns === lastNumColumns)
                break;

            const layout = this._layoutStrategy.computeLayout(this._sortedWindows, {
                numRows,
            });

            const [scale, space] = this._layoutStrategy.computeScaleAndSpace(layout, area);

            if (lastLayout && !this._isBetterScaleAndSpace(lastScale, lastSpace, scale, space))
                break;

            lastLayout = layout;
            lastNumColumns = numColumns;
            lastScale = scale;
            lastSpace = space;
        }

        return lastLayout;
    });


    registerOverridePrototype(Workspace.Workspace, '_isOverviewWindow', win => {
        win = win.meta_window ?? win; // should be metawindow, but get if not
        // upstream (gnome value result - whta it would have done)
        const saved = getSavedPrototype(Workspace.Workspace, '_isOverviewWindow');
        const upstreamValue = saved?.call(this, win) ?? !win.skip_taskbar;

        if (Scratch.isScratchWindow(win)) {
            if (gsettings.get_boolean('only-scratch-in-overview')) {
                return upstreamValue;
            }

            if (gsettings.get_boolean('disable-scratch-in-overview')) {
                return false;
            }
        }

        // if here then not scratch
        if (gsettings.get_boolean('only-scratch-in-overview')) {
            return false;
        }

        return upstreamValue;
    });

    const checkScratch = (metaWindow, metaWorkspace) => {
        if (Scratch.isScratchWindow(metaWindow)) {
            // check workspace match
            return metaWorkspace === metaWindow?.get_workspace();
        }

        return false;
    };
    registerOverridePrototype(Workspace.Workspace, '_isMyWindow', function(window) {
        if (checkScratch(window, this.metaWorkspace)) {
            return true;
        }

        const space = Tiling.spaces.spaceOf(this.metaWorkspace);
        const onSpace = space.indexOf(window) >= 0;
        const onMonitor = this._monitor === space.monitor;
        return onSpace && onMonitor;
    });
    registerOverridePrototype(WorkspaceThumbnail.WorkspaceThumbnail, '_isMyWindow', function(actor) {
        const window = actor.meta_window;
        if (checkScratch(window, this.metaWorkspace)) {
            return true;
        }

        const space = Tiling.spaces.spaceOf(this.metaWorkspace);
        const onSpace = space.indexOf(window) >= 0;
        const onMonitor = this.monitorIndex === space.monitor.index;
        return onSpace && onMonitor;
    });

    /**
     * Resolve issue where window that is set to minimise-on-close should be removed
     * from tiling (stick) before closing.  See https://github.com/paperwm/PaperWM/issues/608.
     */
    registerOverridePrototype(WindowPreview.WindowPreview, '_deleteAll', function() {
        const windows = this.window_container.layout_manager.get_windows();

        // Delete all windows, starting from the bottom-most (most-modal) one
        for (const window of windows.reverse()) {
            window.stick();
            window.delete(global.get_current_time());
        }

        this._closeRequested = true;
    });

    /**
     * Always show workspace thumbnails in overview if more than one workspace.
     * See original function at:
     * https://gitlab.gnome.org/GNOME/gnome-shell/-/blob/gnome-44/js/ui/workspaceThumbnail.js#L690
     */
    registerOverridePrototype(WorkspaceThumbnail.ThumbnailsBox, '_updateShouldShow',
        function () {
            const { nWorkspaces } = global.workspace_manager;
            const shouldShow = nWorkspaces > 1;

            if (this._shouldShow === shouldShow)
                return;

            this._shouldShow = shouldShow;
            this.notify('should-show');
        });

    /**
     * Provides ability to set AltTab window preview sizes (which is a little harder in 45+).
     * https://gitlab.gnome.org/GNOME/gnome-shell/-/blob/main/js/ui/altTab.js#L1002
     */
    registerOverridePrototype(AltTab.WindowIcon, '_init', function(window, mode) {
        const saved = getSavedPrototype(AltTab.WindowIcon, '_init');
        saved.call(this, window, mode);

        const WINDOW_PREVIEW_SIZE = 128;
        const AppIconMode = {
            THUMBNAIL_ONLY: 1,
            APP_ICON_ONLY: 2,
            BOTH: 3,
        };
        const APP_ICON_SIZE = 96;
        const APP_ICON_SIZE_SMALL = 48;

        let mutterWindow = this.window.get_compositor_private();

        this._icon.destroy_all_children();

        this.monitor = Tiling.spaces.selectedSpace.monitor;
        let _createWindowClone = (window, size) => {
            let [width, height] = window.get_size();
            let scale = Math.min(1.0, size / width, size / height);
            return new Clutter.Clone({
                source: window,
                width: width * scale,
                height: height * scale,
                x_align: Clutter.ActorAlign.CENTER,
                y_align: Clutter.ActorAlign.CENTER,
                // usual hack for the usual bug in ClutterBinLayout...
                x_expand: true,
                y_expand: true,
            });
        };

        let size;
        let scaleFactor = St.ThemeContext.get_for_stage(global.stage).scale_factor;
        const scale = Settings.prefs.window_switcher_preview_scale;
        // scale size based on PaperWM's minimap-scale
        if (scale > 0) {
            size = Math.round(this.monitor.height * scale);
        } else {
            size = WINDOW_PREVIEW_SIZE;
        }
        switch (mode) {
        case AppIconMode.THUMBNAIL_ONLY:
            this._icon.add_child(_createWindowClone(mutterWindow, size * scaleFactor));
            break;

        case AppIconMode.BOTH:
            this._icon.add_child(_createWindowClone(mutterWindow, size * scaleFactor));

            if (this.app) {
                this._icon.add_child(
                    this._createAppIcon(this.app, APP_ICON_SIZE_SMALL));
            }
            break;

        case AppIconMode.APP_ICON_ONLY:
            size = APP_ICON_SIZE;
            this._icon.add_child(this._createAppIcon(this.app, size));
        }

        this._icon.set_size(size * scaleFactor, size * scaleFactor);
    });

    registerOverridePrototype(Screenshot.ScreenshotUI, 'open', async function(mode) {
        const saved = getSavedPrototype(Screenshot.ScreenshotUI, 'open');

        if (!Main.overview.visible) {
            Tiling?.spaces.forEach(s => {
                s.visible.forEach(w => {
                    w.get_compositor_private()?.remove_clip();
                });
            });
        }

        await saved.call(this, mode);
    });

    registerOverridePrototype(Screenshot.ScreenshotUI, 'close', function(instantly) {
        const saved = getSavedPrototype(Screenshot.ScreenshotUI, 'close');

        if (!Main.overview.visible) {
            Tiling?.spaces.forEach(s => {
                s.visible.forEach(w => {
                    s.applyClipToClone(w);
                });
            });
        }

        saved.call(this, instantly);
    });
}

/**
 * Enables any registered overrides.
 */
export function enableOverrides() {
    for (let [obj, props] of savedProps) {
        for (let name in props) {
            enableOverride(obj, name);
        }
    }
}

export function disableOverrides() {
    for (let [obj, props] of savedProps) {
        for (let name in props) {
            obj[name] = props[name].saved;
        }
    }
}

/**
 * Saves the original setting value (boolean) to restore on disable.
 * We save a backup of the user's setting to PaperWM settings (schema)
 * for safety (in case gnome terminates etc.).  This ensures original
 * user settings will be restored on next PaperWM disable.
 * @param key
 */
let runtimeDisables = [];
export function saveRuntimeDisable(schemaSettings, key, disableValue) {
    try {
        let origValue = schemaSettings.get_boolean(key);
        schemaSettings.set_boolean(key, disableValue);

        // save a backup copy to PaperWM settings (for restore)
        let pkey = `restore-${key}`;

        /**
         * Now if paperwm settings has restore values, it means
         * that they weren't previously restore properly (since on
         * successful restore we clear the values).
         */
        if (gsettings.get_string(pkey) === '') {
            gsettings.set_string(pkey, origValue.toString());
        }

        // we want to restore from PaperWM back settings (safer)
        let restore = () => {
            let value = gsettings.get_string(pkey);
            // if value is empty, do nothing
            if (value === '') {
                return;
            }

            let bvalue = value === 'true';
            schemaSettings.set_boolean(key, bvalue);

            // after restore, empty papermw saved value
            gsettings.set_string(pkey, '');
        };

        runtimeDisables.push(restore);
    } catch (e) {
        console.error(e);
    }
}

/**
 * PaperWM disables certain behaviours during runtime.
 * The user original settings are saved to PaperWM's settings (schema) for restoring
 * purposes (we save to PaperWM's setting just in gnome terminates before PaperWM can
 * restore the original user settings).  These settings are then restored on disable().
 */
export function setupRuntimeDisables() {
    saveRuntimeDisable(mutterSettings, 'attach-modal-dialogs', false);
    saveRuntimeDisable(mutterSettings, 'workspaces-only-on-primary', false);
    saveRuntimeDisable(mutterSettings, 'edge-tiling', false);
}

/**
 * Restores the runtime settings that were disabled when
 * PaperWM was enabled.
 */
export function restoreRuntimeDisables() {
    if (Main.sessionMode.isLocked) {
        return;
    }
    runtimeDisables.forEach(restore => {
        try {
            restore();
        } catch (e) {
            console.error(e);
        }
    });
}

/**
 * Swipetrackers that should be disabled.  Locations of swipetrackers may
 * move from gnome version to gnome version.  Next to the swipe tracker locations
 * below are the gnome versions when they were first (or last) seen.
 */
export let swipeTrackers; // exported
export function setupSwipeTrackers() {
    swipeTrackers = [
        Main?.overview?._swipeTracker, // gnome 40+
        Main?.overview?._overview?._controls?._workspacesDisplay?._swipeTracker, // gnome 40+
        Main?.wm?._workspaceAnimation?._swipeTracker, // gnome 40+
        Main?.wm?._swipeTracker, // gnome 38 (and below)
    ].filter(t => typeof t !== 'undefined');
}

let actions;
export function setupActions() {
    /*
     * Some actions work rather poorly.
     * In particular the 3-finger hold + tap can randomly activate a minimized
     * window when tapping after a 3-finger swipe
     */
    // eslint-disable-next-line array-callback-return
    actions = global.stage.get_actions().filter(a => {
        switch (a.constructor) {
        case WindowManager.AppSwitchAction:
            return true;
        }
    });
    actions.forEach(a => global.stage.remove_action(a));
}

export function _checkWorkspaces() {
    let workspaceManager = global.workspace_manager;
    let i;
    let emptyWorkspaces = [];
    let minimum = Main.layoutManager.monitors.length + 1;

    if (!Meta.prefs_get_dynamic_workspaces()) {
        // if less spaces than minimum, create!
        let created = 0;
        while (workspaceManager.nWorkspaces < minimum) {
            workspaceManager.append_new_workspace(false, global.get_current_time());
            created++;
        }

        if (created > 0) {
            Main.notify(
                `PaperWM (created ${created} workspaces)`,
                `PaperWM requires a minimum of ${minimum} workspaces for you monitor configuration.`
            );
        }

        this._checkWorkspacesId = 0;
        return false;
    }

    // Update workspaces only if Dynamic Workspace Management has not been paused by some other function
    if (this._pauseWorkspaceCheck || Tiling.inPreview)
        return true;

    for (i = 0; i < this._workspaces.length; i++) {
        let lastRemoved = this._workspaces[i]._lastRemovedWindow;
        if ((lastRemoved &&
             (lastRemoved.get_window_type() === Meta.WindowType.SPLASHSCREEN ||
              lastRemoved.get_window_type() === Meta.WindowType.DIALOG ||
              lastRemoved.get_window_type() === Meta.WindowType.MODAL_DIALOG)) ||
            this._workspaces[i]._keepAliveId)
            emptyWorkspaces[i] = false;
        else
            emptyWorkspaces[i] = true;
    }

    let sequences = Shell.WindowTracker.get_default().get_startup_sequences();
    for (i = 0; i < sequences.length; i++) {
        let index = sequences[i].get_workspace();
        if (index >= 0 && index <= workspaceManager.n_workspaces)
            emptyWorkspaces[index] = false;
    }

    let windows = global.get_window_actors();
    for (i = 0; i < windows.length; i++) {
        let actor = windows[i];
        let win = actor.get_meta_window();

        if (win.is_on_all_workspaces())
            continue;

        let workspaceIndex = win.get_workspace().index();
        emptyWorkspaces[workspaceIndex] = false;
    }

    /**
     * Set minimum workspaces to be max of num_monitors+1.
     * This ensures that we have at least one workspace at the end.
     */
    // Make sure we have a minimum number of spaces
    for (i = 0; i < minimum; i++) {
        if (i >= emptyWorkspaces.length) {
            workspaceManager.append_new_workspace(false, global.get_current_time());
            emptyWorkspaces.push(true);
        }
    }

    // If we don't have an empty workspace at the end, add one
    if (!emptyWorkspaces[emptyWorkspaces.length - 1]) {
        workspaceManager.append_new_workspace(false, global.get_current_time());
        emptyWorkspaces.push(true);
    }

    let lastIndex = emptyWorkspaces.length - 1;
    let lastEmptyIndex = emptyWorkspaces.lastIndexOf(false) + 1;
    let activeWorkspaceIndex = workspaceManager.get_active_workspace_index();

    // Keep the active workspace
    emptyWorkspaces[activeWorkspaceIndex] = false;

    // Keep a minimum number of spaces
    for (i = 0; i < Math.max(Main.layoutManager.monitors.length, minimum); i++) {
        emptyWorkspaces[i] = false;
    }

    // Keep visible spaces
    if (Tiling?.spaces?.monitors) {
        for (let [, space] of Tiling.spaces.monitors) {
            emptyWorkspaces[space.workspace.index()] = false;
        }
    }

    // Delete empty workspaces except for the last one; do it from the end
    // to avoid index changes
    for (i = lastIndex; i >= 0; i--) {
        // eslint-disable-next-line eqeqeq
        if (emptyWorkspaces[i] && i != lastEmptyIndex) {
            workspaceManager.remove_workspace(this._workspaces[i]
                , global.get_current_time());
        }
    }

    this._checkWorkspacesId = 0;
    return false;
}