build-update-repo: Fix org.telegram.desktop icons

The telegram app id is org.telegram.desktop, and its appstream
component id is org.telegram.desktop.desktop, which we did not
properly handle (we special cased the app-id-ends-with-desktop case
and then did not remote .desktop). This replaces that with a more
approach that *always* matches the whole app id as prefix, and then
replaces a ".desktop" in the suffix part only.

Closes: #1593
Approved by: alexlarsson

common/flatpak-utils.c

@@ -3482,6 +3482,7 @@ extract_appstream (OstreeRepo *repo,
  {
  FlatpakXml *component_id, *component_id_text_node;
  g_autofree char *component_id_text = NULL;
+ char *component_id_suffix;
 
  if (g_strcmp0 (component->element_name, "component") != 0)
  {
@@ -3494,18 +3495,22 @@ extract_appstream (OstreeRepo *repo,
 
  component_id_text = g_strstrip (g_strdup (component_id_text_node->text));
 
- /* .desktop suffix in component ID is suggested, not required
- (unless app ID actually ends in .desktop) */
- if (g_str_has_suffix (component_id_text, ".desktop") &&
- !g_str_has_suffix (id, ".desktop"))
- component_id_text[strlen (component_id_text) - strlen (".desktop")] = 0;
+ /* We're looking for a component that matches the app-id (id), but it
+ may have some further elements (separated by dot) and can also have
+ ".desktop" at the end which we need to strip out. Further complicating
+ things, some actual app ids ends in .desktop, such as org.telegram.desktop. */
 
- if (!g_str_has_prefix (component_id_text, id))
+ component_id_suffix = component_id_text + strlen (id); /* Don't deref before we check for prefix match! */
+ if (!g_str_has_prefix (component_id_text, id) ||
+ (component_id_suffix[0] != 0 && component_id_suffix[0] != '.'))
  {
  component = component->next_sibling;
  continue;
  }
 
+ if (g_str_has_suffix (component_id_suffix, ".desktop"))
+ component_id_suffix[strlen (component_id_suffix) - strlen (".desktop")] = 0;
+
  g_print (_("Extracting icons for component %s\n"), component_id_text);
 
  if (!copy_icon (component_id_text, root, dest, "64x64", &my_error))