[libnotify] notification: Do not prepend SNAP prefix when is already present

[Marco Trevisan <marcotrevi src gnome org>]

commit c4d5ea8baff20bd6594faa310b38e8d2feb2d54d
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Thu Apr 21 18:29:55 2022 +0200

    notification: Do not prepend SNAP prefix when is already present
    
    We used to just add it again, to eventually figure out that the file
    did not exists, but may not work properly in some scenarios.
    
    Also always fill the path_filename when using a file-name only, as that
    may be refer to something under the SNAP path, and in such case we want
    to try check if that exists before giving up.

 libnotify/notification.c | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)
---
diff --git a/libnotify/notification.c b/libnotify/notification.c
index 55cc46f..be8bfac 100644
--- a/libnotify/notification.c
+++ b/libnotify/notification.c
@@ -443,16 +443,27 @@ try_prepend_path (const char *base_path,
                         path_filename = g_strdup (base_path);
                 } else {
                         path_filename = realpath (base_path, NULL);
+
+                        if (path_filename == NULL) {
+                                /* File path is not existing, but let's check
+                                 * if it's under the base path before giving up
+                                 */
+                                path_filename = g_strdup (base_path);
+                        }
                 }
         }
 
-        g_debug ("Trying to look at file '%s' in the '%s' prefix.",
-                 base_path,
-                 path);
-
-        path_ret = g_build_filename (path, path_filename, NULL);
+        if (g_str_has_prefix (path_filename, path)) {
+                path_ret = g_strdup (path_filename);
+        } else {
+                g_debug ("Trying to look at file '%s' in the '%s' prefix.",
+                         base_path,
+                         path);
+                path_ret = g_build_filename (path, path_filename, NULL);
+        }
 
         if (!g_file_test (path_ret, G_FILE_TEST_EXISTS)) {
+                g_debug ("Nothing found at %s", path_ret);
                 g_free (path_ret);
                 path_ret = NULL;
         }