Make AppSystem not a singleton

src/AppSystem/App.vala

@@ -22,6 +22,7 @@ public class Dock.App : Object {
 
     public signal void removed ();
 
+    public unowned AppSystem app_system { get; construct; }
     public bool pinned { get; construct set; }
     public GLib.DesktopAppInfo app_info { get; construct; }
 
@@ -52,8 +53,8 @@ public class Dock.App : Object {
 
     private static Dock.SwitcherooControl switcheroo_control;
 
-    public App (GLib.DesktopAppInfo app_info, bool pinned) {
-        Object (app_info: app_info, pinned: pinned);
+    public App (AppSystem app_system, GLib.DesktopAppInfo app_info, bool pinned) {
+        Object (app_system: app_system, app_info: app_info, pinned: pinned);
     }
 
     static construct {
@@ -255,7 +256,7 @@ public class Dock.App : Object {
         if (timer_id != 0) {
             Source.remove (timer_id);
         } else {
-            yield AppSystem.get_default ().sync_windows (); // Get the current stacking order
+            yield app_system.sync_windows (); // Get the current stacking order
             current_index = windows.length > 1 && windows[0].has_focus ? 1 : 0;
             current_windows = {};
             foreach (var window in windows) {

src/AppSystem/AppSystem.vala

@@ -5,21 +5,20 @@
 
 public class Dock.AppSystem : Object, UnityClient {
     private static Settings settings;
-    private static GLib.Once<AppSystem> instance;
 
     static construct {
         settings = new Settings ("io.elementary.dock");
     }
 
-    public static unowned AppSystem get_default () {
-        return instance.once (() => { return new AppSystem (); });
-    }
-
     public signal void app_added (App app);
 
+    public WindowSystem window_system { get; construct; }
+
     private GLib.HashTable<unowned string, App> id_to_app;
 
-    private AppSystem () { }
+    public AppSystem (WindowSystem window_system) {
+        Object (window_system: window_system);
+    }
 
     construct {
         id_to_app = new HashTable<unowned string, App> (str_hash, str_equal);
@@ -36,19 +35,19 @@ public class Dock.AppSystem : Object, UnityClient {
         }
 
         yield sync_windows ();
-        WindowSystem.get_default ().notify["windows"].connect (sync_windows);
+        window_system.notify["windows"].connect (sync_windows);
     }
 
     private App add_app (DesktopAppInfo app_info, bool pinned) {
-        var app = new App (app_info, pinned);
+        var app = new App (this, app_info, pinned);
         id_to_app[app_info.get_id ()] = app;
         app.removed.connect ((_app) => id_to_app.remove (_app.app_info.get_id ()));
         app_added (app);
         return app;
     }
 
     public async void sync_windows () {
-        var windows = WindowSystem.get_default ().windows;
+        var windows = window_system.windows;
 
         var app_window_list = new GLib.HashTable<App, GLib.GenericArray<Window>> (direct_hash, direct_equal);
         foreach (var window in windows) {

src/Application.vala

@@ -4,6 +4,8 @@
  */
 
 public class Dock.Application : Gtk.Application {
+    private AppSystem app_system;
+
     public Application () {
         Object (application_id: "io.elementary.dock");
     }
@@ -14,6 +16,9 @@ public class Dock.Application : Gtk.Application {
         Granite.init ();
         ShellKeyGrabber.init ();
         GalaDBus.init.begin ();
+
+        app_system = new AppSystem (WindowSystem.get_default ());
+        ItemManager.init (app_system);
     }
 
     protected override void activate () {
@@ -23,7 +28,7 @@ public class Dock.Application : Gtk.Application {
             add_window (main_window);
 
             unowned var unity_client = Unity.get_default ();
-            unity_client.add_client (AppSystem.get_default ());
+            unity_client.add_client (app_system);
         }
 
         active_window.present ();
@@ -32,7 +37,7 @@ public class Dock.Application : Gtk.Application {
     public override bool dbus_register (DBusConnection connection, string object_path) throws Error {
         base.dbus_register (connection, object_path);
 
-        connection.register_object (object_path, new ItemInterface ());
+        connection.register_object (object_path, new ItemInterface (app_system));
 
         return true;
     }

src/DBus/ItemInterface.vala

@@ -5,15 +5,23 @@
 
 [DBus (name = "io.elementary.dock.items")]
 public class Dock.ItemInterface : Object {
+    [DBus (visible = false)]
+    public AppSystem app_system { private get; construct; }
+
+    [DBus (visible = false)]
+    public ItemInterface (AppSystem app_system) {
+        Object (app_system: app_system);
+    }
+
     public void add_launcher (string app_id) throws DBusError, IOError {
-        AppSystem.get_default ().add_app_for_id (app_id);
+        app_system.add_app_for_id (app_id);
     }
 
     public void remove_launcher (string app_id) throws DBusError, IOError {
-        AppSystem.get_default ().remove_app_by_id (app_id);
+        app_system.remove_app_by_id (app_id);
     }
 
     public string[] list_launchers () throws DBusError, IOError {
-        return AppSystem.get_default ().list_launchers ();
+        return app_system.list_launchers ();
     }
 }

src/ItemManager.vala

@@ -6,11 +6,18 @@
  public class Dock.ItemManager : Gtk.Fixed {
     private static Settings settings;
 
-    private static GLib.Once<ItemManager> instance;
+    private static ItemManager instance;
+
+    public static void init (AppSystem app_system) {
+        instance = new ItemManager (app_system);
+    }
+
     public static unowned ItemManager get_default () {
-        return instance.once (() => { return new ItemManager (); });
+        return instance;
     }
 
+    public AppSystem app_system { private get; construct; }
+
     public Launcher? added_launcher { get; set; default = null; }
 
     private Adw.TimedAnimation resize_animation;
@@ -27,6 +34,10 @@
         settings = new Settings ("io.elementary.dock");
     }
 
+    private ItemManager (AppSystem app_system) {
+        Object (app_system: app_system);
+    }
+
     construct {
         launchers = new GLib.GenericArray<Launcher> ();
 
@@ -88,8 +99,6 @@
                 return;
             }
 
-            var app_system = AppSystem.get_default ();
-
             var app = app_system.get_app (app_info.get_id ());
             if (app != null) {
                 app.pinned = true;
@@ -145,7 +154,7 @@
             return false;
         });
 
-        AppSystem.get_default ().app_added.connect ((app) => {
+        app_system.app_added.connect ((app) => {
             var launcher = new Launcher (app);
 
             if (drop_target_file.get_value () != null && added_launcher == null) { // The launcher is being added via dnd from wingpanel
@@ -167,7 +176,7 @@
 #endif
 
         map.connect (() => {
-            AppSystem.get_default ().load.begin ();
+            app_system.load.begin ();
             background_item.load ();
 #if WORKSPACE_SWITCHER
             WorkspaceSystem.get_default ().load.begin ();