Load notifications without blocking

data/notifications.appdata.xml.in

@@ -7,6 +7,18 @@
   <summary>See missed notifications in the panel</summary>
   <icon type="stock">preferences-system-notifications</icon>
   <releases>
+    <release version="6.0.5" date="2021-12-17" urgency="medium">
+      <description>
+        <p>Fixes:</p>
+        <ul>
+          <li>Reduce delay in initially showing wingpanel when there is a large number of notifications</li>
+        </ul>
+        <p>Minor updates:</p>
+        <ul>
+          <li>Updated translations</li>
+        </ul>
+      </description>
+    </release>
     <release version="6.0.4" date="2021-12-17" urgency="medium">
       <description>
         <p>Fixes:</p>

src/Indicator.vala

@@ -27,6 +27,7 @@ public class Notifications.Indicator : Wingpanel.Indicator {
     private Gtk.ModelButton clear_all_btn;
     private Gtk.Spinner? dynamic_icon = null;
     private NotificationsList nlist;
+    private List<Notification> previous_session = null;
 
     public Indicator () {
         Object (
@@ -45,29 +46,30 @@ public class Notifications.Indicator : Wingpanel.Indicator {
 
     public override Gtk.Widget get_display_widget () {
         if (dynamic_icon == null) {
-            dynamic_icon = new Gtk.Spinner ();
-            dynamic_icon.active = true;
-
-            nlist = new NotificationsList ();
-
-            var previous_session = Session.get_instance ().get_session_notifications ();
-            previous_session.foreach ((notification) => {
-                nlist.add_entry (notification, false);
-            });
-
             Gtk.IconTheme.get_default ().add_resource_path ("/io/elementary/wingpanel/notifications");
 
             var provider = new Gtk.CssProvider ();
             provider.load_from_resource ("io/elementary/wingpanel/notifications/indicator.css");
 
+            dynamic_icon = new Gtk.Spinner () {
+                active = true,
+                tooltip_markup = _("Updating notifications…")
+            };
+
             unowned var dynamic_icon_style_context = dynamic_icon.get_style_context ();
-            dynamic_icon_style_context.add_class ("notification-icon");
             dynamic_icon_style_context.add_provider (provider, Gtk.STYLE_PROVIDER_PRIORITY_APPLICATION);
+            dynamic_icon_style_context.add_class ("notification-icon");
+
+            nlist = new NotificationsList ();
 
             var monitor = NotificationMonitor.get_instance ();
             monitor.notification_received.connect (on_notification_received);
             monitor.notification_closed.connect (on_notification_closed);
 
+            notify_settings.changed["do-not-disturb"].connect (() => {
+                set_display_icon_name ();
+            });
+
             dynamic_icon.button_press_event.connect ((e) => {
                 if (e.button == Gdk.BUTTON_MIDDLE) {
                     notify_settings.set_boolean ("do-not-disturb", !notify_settings.get_boolean ("do-not-disturb"));
@@ -77,19 +79,27 @@ public class Notifications.Indicator : Wingpanel.Indicator {
                 return Gdk.EVENT_PROPAGATE;
             });
 
-            notify_settings.changed["do-not-disturb"].connect (() => {
-                set_display_icon_name ();
-            });
-
-            nlist.add.connect (set_display_icon_name);
-            nlist.remove.connect (set_display_icon_name);
+            previous_session = Session.get_instance ().get_session_notifications ();
+            Timeout.add (2000, () => { // Do not block animated drawing of wingpanel
+                load_session_notifications.begin (() => { // load asynchromously so spinner continues to rotate
+                    set_display_icon_name ();
+                    nlist.add.connect (set_display_icon_name);
+                    nlist.remove.connect (set_display_icon_name);
+                });
 
-            set_display_icon_name ();
+                return Source.REMOVE;
+            });
         }
 
         return dynamic_icon;
     }
 
+    private async void load_session_notifications () {
+        foreach (var notification in previous_session) {
+            yield nlist.add_entry (notification, false); // This is slow as NotificationEntry is complex
+        }
+    }
+
     public override Gtk.Widget? get_widget () {
         if (main_box == null) {
             var not_disturb_switch = new Granite.SwitchModelButton (_("Do Not Disturb"));
@@ -170,7 +180,7 @@ public class Notifications.Indicator : Wingpanel.Indicator {
         }
 
         if (app_settings == null || app_settings.get_boolean (REMEMBER_KEY)) {
-            nlist.add_entry (notification);
+            nlist.add_entry.begin (notification, true);
         }
 
         set_display_icon_name ();
@@ -216,9 +226,8 @@ public class Notifications.Indicator : Wingpanel.Indicator {
     }
 
     private void update_tooltip () {
-        uint number_of_notifications = Session.get_instance ().get_session_notifications ().length ();
+        uint number_of_notifications = Session.get_instance ().count_notifications ();
         int number_of_apps = nlist.app_entries.size;
-
         string description;
         string accel_label;
 

src/Services/Session.vala

@@ -78,17 +78,27 @@ public class Notifications.Session : GLib.Object {
                     key.get_string (group, SENDER_KEY),
                     key.get_boolean (group, HAS_TEMP_FILE_KEY)
                 );
-                list.append (notification);
+                list.prepend (notification);
             }
         } catch (KeyFileError e) {
             warning (e.message);
         } catch (FileError e) {
             warning (e.message);
         }
 
+        list.reverse ();
         return list;
     }
 
+    public uint count_notifications () {
+        uint count = 0;
+        foreach (unowned string group in key.get_groups ()) {
+            count++;
+        }
+
+        return count;
+    }
+
     public void add_notification (Notification notification, bool write_file = true) {
         string id = notification.id.to_string ();
         key.set_int64 (id, UNIX_TIME_KEY, notification.timestamp.to_unix ());
@@ -152,11 +162,21 @@ public class Notifications.Session : GLib.Object {
         }
     }
 
+    private uint write_timeout_id = 0;
     private void write_contents () {
-        try {
-            FileUtils.set_contents (session_file.get_path (), key.to_data ());
-        } catch (FileError e) {
-            warning (e.message);
+        if (write_timeout_id > 0) {
+            Source.remove (write_timeout_id);
         }
+
+        write_timeout_id = Timeout.add (1000, () => {
+            write_timeout_id = 0;
+            try {
+                FileUtils.set_contents (session_file.get_path (), key.to_data ());
+            } catch (FileError e) {
+                warning (e.message);
+            }
+
+            return Source.REMOVE;
+        });
     }
 }

src/Widgets/NotificationsList.vala

@@ -46,7 +46,7 @@ public class Notifications.NotificationsList : Gtk.ListBox {
         row_activated.connect (on_row_activated);
     }
 
-    public void add_entry (Notification notification, bool write_file = true) {
+    public async void add_entry (Notification notification, bool add_to_session = true, bool write_file = true) {
         var entry = new NotificationEntry (notification);
 
         if (app_entries[notification.desktop_id] != null) {
@@ -71,7 +71,12 @@ public class Notifications.NotificationsList : Gtk.ListBox {
 
         show_all ();
 
-        Session.get_instance ().add_notification (notification, write_file);
+        Idle.add (add_entry.callback);
+        yield;
+
+        if (add_to_session) { // If notification was obtained from session do not write it back
+            Session.get_instance ().add_notification (notification);
+        }
     }
 
     public void clear_all () {