Implement background app monitoring

Author: leolost2605

data/background.svg

@@ -2,6 +2,7 @@
 <gresources>
   <gresource prefix="/io/elementary/dock">
     <file compressed="true">Application.css</file>
+    <file compressed="true">background.svg</file>
     <file compressed="true">poof.svg</file>
   </gresource>
 </gresources>

data/dock.gresource.xml

@@ -17,11 +17,14 @@ public class Dock.AppSystem : Object, UnityClient {
 
     public signal void app_added (App app);
 
+    public BackgroundMonitor background_monitor { get; construct; }
+
     private GLib.HashTable<unowned string, App> id_to_app;
 
     private AppSystem () { }
 
     construct {
+        background_monitor = new BackgroundMonitor ();
         id_to_app = new HashTable<unowned string, App> (str_hash, str_equal);
     }
 

src/AppSystem/AppSystem.vala

@@ -0,0 +1,30 @@
+/*
+ * SPDX-License-Identifier: GPL-3.0
+ * SPDX-FileCopyrightText: 2025 elementary, Inc. (https://elementary.io)
+ *
+ * Authored by: Leonhard Kargl <[email protected]>
+ */
+
+public class Dock.BackgroundApp : Object {
+    public DesktopAppInfo app_info { get; construct; }
+    public string? instance { get; construct; }
+    public string? message { get; construct; }
+
+    public BackgroundApp (DesktopAppInfo app_info, string? instance, string? message) {
+        Object (app_info: app_info, instance: instance, message: message);
+    }
+
+    public void kill () {
+        if (instance == null) {
+            warning ("No instance to kill");
+            return;
+        }
+
+        try {
+            var app_id = app_info.get_id ().replace (".desktop", "");
+            Process.spawn_command_line_async ("flatpak kill %s".printf (app_id));
+        } catch (Error e) {
+            warning ("Failed to kill instance: %s", e.message);
+        }
+    }
+}

src/AppSystem/Background/BackgroundApp.vala

@@ -0,0 +1,80 @@
+/*
+ * SPDX-License-Identifier: GPL-3.0
+ * SPDX-FileCopyrightText: 2025 elementary, Inc. (https://elementary.io)
+ *
+ * Authored by: Leonhard Kargl <[email protected]>
+ */
+
+public class Dock.BackgroundAppRow : Gtk.ListBoxRow {
+    public BackgroundApp app { get; construct; }
+
+    public BackgroundAppRow (BackgroundApp app) {
+        Object (app: app);
+    }
+
+    construct {
+        var icon = new Gtk.Image.from_gicon (app.app_info.get_icon ()) {
+            icon_size = LARGE
+        };
+
+        var name = new Gtk.Label (app.app_info.get_display_name ()) {
+            xalign = 0,
+            hexpand = true
+        };
+
+        var message = new Gtk.Label (app.message) {
+            xalign = 0,
+            hexpand = true
+        };
+        message.add_css_class (Granite.STYLE_CLASS_DIM_LABEL);
+
+        var button = new Gtk.Button.from_icon_name ("window-close-symbolic") {
+            valign = CENTER,
+            halign = CENTER
+        };
+        button.add_css_class ("circular");
+
+        var spinner = new Gtk.Spinner () {
+            spinning = true
+        };
+
+        var button_stack = new Gtk.Stack () {
+            transition_type = CROSSFADE
+        };
+        button_stack.add_named (button, "button");
+        button_stack.add_named (spinner, "spinner");
+
+        var grid = new Gtk.Grid () {
+            column_spacing = 9,
+            row_spacing = 3,
+            margin_top = 3,
+            margin_bottom = 3,
+            margin_start = 3,
+            margin_end = 3
+        };
+        grid.attach (icon, 0, 0, 1, 2);
+
+        if (app.message != null) {
+            grid.attach (name, 1, 0, 1, 1);
+            grid.attach (message, 1, 1, 1, 1);
+        } else {
+            grid.attach (name, 1, 0, 1, 2);
+        }
+
+        grid.attach (button_stack, 2, 0, 1, 2);
+
+        focusable = false;
+        child = grid;
+
+        button.clicked.connect (() => {
+            button_stack.set_visible_child_name ("spinner");
+            app.kill ();
+
+            Timeout.add_seconds (5, () => {
+                // Assume killing failed
+                button_stack.set_visible_child_name ("button");
+                return Source.REMOVE;
+            });
+        });
+    }
+}

src/AppSystem/Background/BackgroundAppRow.vala

@@ -0,0 +1,42 @@
+/*
+ * SPDX-License-Identifier: GPL-3.0
+ * SPDX-FileCopyrightText: 2025 elementary, Inc. (https://elementary.io)
+ *
+ * Authored by: Leonhard Kargl <[email protected]>
+ */
+
+public class Dock.BackgroundItem : BaseItem {
+    private BackgroundMonitor monitor;
+
+    private Gtk.Popover popover;
+
+    construct {
+        monitor = new BackgroundMonitor ();
+
+        var list_box = new Gtk.ListBox () {
+            selection_mode = NONE,
+            margin_bottom = 3,
+            margin_top = 3,
+        };
+        list_box.bind_model (monitor.background_apps, create_widget_func);
+        list_box.set_placeholder (new Gtk.Label (_("No apps are running in the background")));
+
+        popover = new Gtk.Popover () {
+            position = TOP,
+            child = list_box
+        };
+        popover.set_parent (this);
+
+        var image = new Gtk.Image.from_resource ("/io/elementary/dock/background.svg");
+        bind_property ("icon-size", image, "pixel-size", SYNC_CREATE);
+
+        overlay.child = image;
+
+        gesture_click.released.connect (popover.popup);
+    }
+
+    private Gtk.Widget create_widget_func (Object obj) {
+        var app = (BackgroundApp) obj;
+        return new BackgroundAppRow (app);
+    }
+}