wayland: Launch notifications server as a wayland client (#1882)

lib/Constants.vala

@@ -34,4 +34,10 @@ namespace Gala {
         // Duration of the nudge animation when trying to switch to at the end of the workspace list
         NUDGE = 360,
     }
+
+    /**
+     * Used as a key for Object.set_data<bool> on Meta.Windows that should be
+     * treated as notifications. Has to be set before the window is mapped.
+     */
+    public const string NOTIFICATION_DATA_KEY = "elementary-notification";
 }

src/ShellClients/ManagedClient.vala

@@ -0,0 +1,76 @@
+/*
+ * Copyright 2024 elementary, Inc. (https://elementary.io)
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ * Authored by: Leonhard Kargl <leo.kargl@proton.me>
+ */
+
+/**
+ * Utility class that takes care of launching and restarting a subprocess.
+ * On wayland this uses a WaylandClient and emits window_created if a window for the client was created.
+ * On X this just launches a normal subprocess and never emits window_created.
+ */
+public class Gala.ManagedClient : Object {
+    public signal void window_created (Meta.Window window);
+
+    public Meta.Display display { get; construct; }
+    public string[] args { get; construct; }
+
+    public Meta.WaylandClient? wayland_client { get; private set; }
+
+    public ManagedClient (Meta.Display display, string[] args) {
+        Object (display: display, args: args);
+    }
+
+    construct {
+        if (Meta.Util.is_wayland_compositor ()) {
+            start_wayland.begin ();
+
+            display.window_created.connect ((window) => {
+                if (wayland_client != null && wayland_client.owns_window (window)) {
+                    window_created (window);
+                }
+            });
+        } else {
+            start_x.begin ();
+        }
+    }
+
+    private async void start_wayland () {
+        var subprocess_launcher = new GLib.SubprocessLauncher (STDERR_PIPE | STDOUT_PIPE);
+        try {
+#if HAS_MUTTER44
+            wayland_client = new Meta.WaylandClient (display.get_context (), subprocess_launcher);
+#else
+            wayland_client = new Meta.WaylandClient (subprocess_launcher);
+#endif
+            var subprocess = wayland_client.spawnv (display, args);
+
+            yield subprocess.wait_async ();
+
+            //Restart the daemon if it crashes
+            Timeout.add_seconds (1, () => {
+                start_wayland.begin ();
+                return Source.REMOVE;
+            });
+        } catch (Error e) {
+            warning ("Failed to create dock client: %s", e.message);
+            return;
+        }
+    }
+
+    private async void start_x () {
+        try {
+            var subprocess = new Subprocess.newv (args, NONE);
+            yield subprocess.wait_async ();
+
+            //Restart the daemon if it crashes
+            Timeout.add_seconds (1, () => {
+                start_x.begin ();
+                return Source.REMOVE;
+            });
+        } catch (Error e) {
+            warning ("Failed to create daemon subprocess with x: %s", e.message);
+        }
+    }
+}

src/ShellClients/NotificationsClient.vala

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2024 elementary, Inc. (https://elementary.io)
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ * Authored by: Leonhard Kargl <leo.kargl@proton.me>
+ */
+
+public class Gala.NotificationsClient : Object {
+    public Meta.Display display { get; construct; }
+
+    private ManagedClient client;
+
+    public NotificationsClient (Meta.Display display) {
+        Object (display: display);
+    }
+
+    construct {
+        client = new ManagedClient (display, { "io.elementary.notifications" });
+
+        client.window_created.connect ((window) => {
+            window.set_data (NOTIFICATION_DATA_KEY, true);
+            window.make_above ();
+#if HAS_MUTTER_46
+            client.wayland_client.make_dock (window);
+#endif
+        });
+    }
+}

src/ShellClients/ShellClientsManager.vala

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2024 elementary, Inc. (https://elementary.io)
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ * Authored by: Leonhard Kargl <leo.kargl@proton.me>
+ */
+
+public class Gala.ShellClientsManager : Object {
+    public Meta.Display display { get; construct; }
+
+    private NotificationsClient notifications_client;
+
+    public ShellClientsManager (Meta.Display display) {
+        Object (display: display);
+    }
+
+    construct {
+        notifications_client = new NotificationsClient (display);
+    }
+}

src/WindowManager.vala

@@ -83,6 +83,8 @@ namespace Gala {
 
         private DaemonManager daemon_manager;
 
+        private ShellClientsManager shell_clients_manager;
+
         private WindowGrabTracker window_grab_tracker;
 
         private NotificationStack notification_stack;
@@ -143,6 +145,7 @@ namespace Gala {
         }
 
         public override void start () {
+            shell_clients_manager = new ShellClientsManager (get_display ());
             daemon_manager = new DaemonManager (get_display ());
             window_grab_tracker = new WindowGrabTracker (get_display ());
 
@@ -1446,10 +1449,20 @@ namespace Gala {
                 move_window_to_next_ws (window);
             }
 
-            // Notifications are a special case and have to be always be handled
+            actor.remove_all_transitions ();
-            // regardless of the animation setting
-            if (!enable_animations && window.window_type != Meta.WindowType.NOTIFICATION) {
             actor.show ();
+
+            // Notifications are a special case and have to be always be handled
+            // (also regardless of the animation setting)
+            if (window.get_data (NOTIFICATION_DATA_KEY) || window.window_type == NOTIFICATION) {
+                clutter_actor_reparent (actor, notification_group);
+                notification_stack.show_notification (actor, enable_animations);
+
+                map_completed (actor);
+                return;
+            }
+
+            if (!enable_animations) {
                 map_completed (actor);
 
                 if (InternalUtils.get_window_is_normal (window) && window.get_layer () == Meta.StackLayer.BOTTOM) {
@@ -1459,9 +1472,6 @@ namespace Gala {
                 return;
             }
 
-            actor.remove_all_transitions ();
-            actor.show ();
-
             switch (window.window_type) {
                 case Meta.WindowType.NORMAL:
                     var duration = AnimationDuration.HIDE;
@@ -1558,12 +1568,6 @@ namespace Gala {
 
                     dim_parent_window (window);
 
-                    break;
-                case Meta.WindowType.NOTIFICATION:
-                    clutter_actor_reparent (actor, notification_group);
-                    notification_stack.show_notification (actor, enable_animations);
-                    map_completed (actor);
-
                     break;
                 default:
                     map_completed (actor);
@@ -1576,7 +1580,30 @@ namespace Gala {
 
             ws_assoc.remove (window);
 
-            if (!enable_animations && window.window_type != Meta.WindowType.NOTIFICATION) {
+            actor.remove_all_transitions ();
+
+            if (window.get_data (NOTIFICATION_DATA_KEY) || window.window_type == NOTIFICATION) {
+                if (enable_animations) {
+                    destroying.add (actor);
+                }
+
+                notification_stack.destroy_notification (actor, enable_animations);
+
+                if (enable_animations) {
+                    ulong destroy_handler_id = 0UL;
+                    destroy_handler_id = actor.transitions_completed.connect (() => {
+                        actor.disconnect (destroy_handler_id);
+                        destroying.remove (actor);
+                        destroy_completed (actor);
+                    });
+                } else {
+                    destroy_completed (actor);
+                }
+
+                return;
+            }
+
+            if (!enable_animations) {
                 destroy_completed (actor);
 
                 if (window.window_type == Meta.WindowType.NORMAL) {
@@ -1586,8 +1613,6 @@ namespace Gala {
                 return;
             }
 
-            actor.remove_all_transitions ();
-
             switch (window.window_type) {
                 case Meta.WindowType.NORMAL:
                     var duration = AnimationDuration.CLOSE;
@@ -1659,25 +1684,6 @@ namespace Gala {
                         destroying.remove (actor);
                         destroy_completed (actor);
                     });
-                    break;
-                case Meta.WindowType.NOTIFICATION:
-                    if (enable_animations) {
-                        destroying.add (actor);
-                    }
-
-                    notification_stack.destroy_notification (actor, enable_animations);
-
-                    if (enable_animations) {
-                        ulong destroy_handler_id = 0UL;
-                        destroy_handler_id = actor.transitions_completed.connect (() => {
-                            actor.disconnect (destroy_handler_id);
-                            destroying.remove (actor);
-                            destroy_completed (actor);
-                        });
-                    } else {
-                        destroy_completed (actor);
-                    }
-
                     break;
                 default:
                     destroy_completed (actor);

src/meson.build

@@ -39,6 +39,9 @@ gala_bin_sources = files(
     'HotCorners/Barrier.vala',
     'HotCorners/HotCorner.vala',
     'HotCorners/HotCornerManager.vala',
+    'ShellClients/ManagedClient.vala',
+    'ShellClients/NotificationsClient.vala',
+    'ShellClients/ShellClientsManager.vala',
     'Widgets/DwellClickTimer.vala',
     'Widgets/IconGroup.vala',
     'Widgets/IconGroupContainer.vala',