[libnotify] notification: Use snap name and app name as fallback desktop-entry

[Marco Trevisan <marcotrevi src gnome org>]

commit 961f45f44c11a7cada11f44bbce1ea8a9eaf5982
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Thu Apr 21 20:08:39 2022 +0200

    notification: Use snap name and app name as fallback desktop-entry
    
    Snaps use desktop IDs based on the snap name and the application name
    inside the snap, so if we're in a such container, we need to compute the
    desktop-entry using those values. We can figure them out from the snap
    cgroup they're in.
    
    In such case, don't even try to use the GApplication ID as that is
    likely wrong in a snapped environment.

 libnotify/notification.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 95 insertions(+), 2 deletions(-)
---
diff --git a/libnotify/notification.c b/libnotify/notification.c
index f4c7139..a451d84 100644
--- a/libnotify/notification.c
+++ b/libnotify/notification.c
@@ -71,6 +71,7 @@ struct _NotifyNotificationPrivate
 
         const char     *snap_path;
         const char     *snap_name;
+        char           *snap_app;
 
         /* NULL to use icon data. Anything else to have server lookup icon */
         char           *icon_name;
@@ -357,6 +358,7 @@ static void
 maybe_initialize_snap (NotifyNotification *obj)
 {
         NotifyNotificationPrivate *priv = obj->priv;
+        gchar *cgroup_contents = NULL;
 
         priv->snap_path = g_getenv ("SNAP");
         if (priv->snap_path == NULL)
@@ -373,8 +375,81 @@ maybe_initialize_snap (NotifyNotification *obj)
                 priv->snap_name = NULL;
         }
 
+        if (g_file_get_contents ("/proc/self/cgroup", &cgroup_contents,
+                                 NULL, NULL)) {
+                gchar **lines = g_strsplit (cgroup_contents, "\n", -1);
+                gchar *found_snap_name = NULL;
+                gint i;
+
+                for (i = 0; lines[i]; ++i) {
+                        gchar **parts = g_strsplit (lines[i], ":", 3);
+                        gchar *basename;
+                        gchar **ns;
+                        guint ns_length;
+
+                        if (g_strv_length (parts) != 3) {
+                                g_strfreev (parts);
+                                continue;
+                        }
+
+                        basename = g_path_get_basename (parts[2]);
+                        g_strfreev (parts);
+
+                        if (!basename) {
+                                continue;
+                        }
+
+                        ns = g_strsplit (basename, ".", -1);
+                        ns_length = g_strv_length (ns);
+                        g_free (basename);
+
+                        if (ns_length < 2 || !g_str_equal (ns[0], "snap")) {
+                                g_strfreev (ns);
+                                continue;
+                        }
+
+                        if (priv->snap_name == NULL) {
+                                g_free (found_snap_name);
+                                found_snap_name = g_strdup (ns[1]);
+                        }
+
+                        if (ns_length < 3) {
+                                g_strfreev (ns);
+                                continue;
+                        }
+
+                        if (priv->snap_name == NULL) {
+                                priv->snap_name = found_snap_name;
+                                found_snap_name = NULL;
+                        }
+
+                        if (g_str_equal (ns[1], priv->snap_name)) {
+                                priv->snap_app = g_strdup (ns[2]);
+                                g_strfreev (ns);
+                                break;
+                        }
+
+                        g_strfreev (ns);
+                }
+
+                if (priv->snap_name == NULL && found_snap_name != NULL) {
+                        priv->snap_name = found_snap_name;
+                        found_snap_name = NULL;
+                }
+
+                g_strfreev (lines);
+                g_free (found_snap_name);
+        }
+
+        if (priv->snap_app == NULL) {
+                priv->snap_app = g_strdup (priv->snap_name);
+        }
+
         g_debug ("SNAP path: %s", priv->snap_path);
         g_debug ("SNAP name: %s", priv->snap_name);
+        g_debug ("SNAP app: %s", priv->snap_app);
+
+        g_free (cgroup_contents);
 }
 
 static void
@@ -409,6 +484,7 @@ notify_notification_finalize (GObject *object)
         g_free (priv->summary);
         g_free (priv->body);
         g_free (priv->icon_name);
+        g_free (priv->snap_app);
 
         if (priv->actions != NULL) {
                 g_slist_foreach (priv->actions, (GFunc) g_free, NULL);
@@ -680,7 +756,7 @@ notify_notification_show (NotifyNotification *notification,
         gpointer                   key, data;
         GVariant                  *result;
 #ifdef GLIB_VERSION_2_32
-        GApplication              *application;
+        GApplication              *application = NULL;
 #endif
 
         g_return_val_if_fail (notification != NULL, FALSE);
@@ -716,8 +792,24 @@ notify_notification_show (NotifyNotification *notification,
                 g_variant_builder_add (&hints_builder, "{sv}", key, data);
         }
 
+        if (priv->snap_app &&
+            g_hash_table_lookup (priv->hints, "desktop-entry") == NULL) {
+                gchar *snap_desktop;
+
+                snap_desktop = g_strdup_printf ("%s_%s",
+                                                priv->snap_name,
+                                                priv->snap_app);
+
+                g_debug ("Using desktop entry: %s", snap_desktop);
+                g_variant_builder_add (&hints_builder, "{sv}",
+                                       "desktop-entry",
+                                       g_variant_new_take_string (snap_desktop));
+        }
+
 #ifdef GLIB_VERSION_2_32
-        application = g_application_get_default ();
+        if (!priv->snap_app) {
+                application = g_application_get_default ();
+        }
 
         if (application != NULL) {
             GVariant *desktop_entry = g_hash_table_lookup (priv->hints, "desktop-entry");
@@ -725,6 +817,7 @@ notify_notification_show (NotifyNotification *notification,
             if (desktop_entry == NULL) {
                 const char *application_id = g_application_get_application_id (application);
 
+                g_debug ("Using desktop entry: %s", application_id);
                 g_variant_builder_add (&hints_builder, "{sv}", "desktop-entry",
                                        g_variant_new_string (application_id));
             }