appDisplay: Handle non-UTF8 filename encodings more gracefully

It may be 2015, but users still stumble upon the occasional .desktop
file that uses a filename encoding other than UTF-8. We currently
fail quite spectacularly in that case by not displaying any apps at
all - handle this case more gracefully, by only filtering out the
offending apps.

https://bugzilla.gnome.org/show_bug.cgi?id=651503

src/shell-app-system.c

@@ -383,3 +383,27 @@ shell_app_system_get_running (ShellAppSystem *self)
 
   return ret;
 }
+
+/**
+ * shell_app_system_search:
+ * @search_string: the search string to use
+ *
+ * Wrapper around g_desktop_app_info_search() that replaces results that
+ * don't validate as UTF-8 with the empty string.
+ *
+ * Returns: (array zero-terminated=1) (element-type GStrv) (transfer full): a
+ *   list of strvs.  Free each item with g_strfreev() and free the outer
+ *   list with g_free().
+ */
+char ***
+shell_app_system_search (const char *search_string)
+{
+    char ***results = g_desktop_app_info_search (search_string);
+
+    for (char ***groups = results; *groups; groups++)
+      for (char **ids = *groups; *ids; ids++)
+        if (!g_utf8_validate (*ids, -1, NULL))
+          **ids = '\0';
+
+      return results;
+}

src/shell-app-system.h

@@ -48,5 +48,6 @@ ShellApp       *shell_app_system_lookup_desktop_wmclass       (ShellAppSystem *s
                                                                const char     *wmclass);
 
 GSList         *shell_app_system_get_running               (ShellAppSystem  *self);
+char         ***shell_app_system_search                    (const char *search_string);
 
 #endif /* __SHELL_APP_SYSTEM_H__ */