[gnome-software] Don't regenerate the shell-extension cache on refresh every time

[Richard Hughes <rhughes src gnome org>]

commit ebd5ce2a04aba58674934574afa9c527cf749835
Author: Richard Hughes <richard hughsie com>
Date:   Mon Apr 11 16:45:39 2016 +0100

    Don't regenerate the shell-extension cache on refresh every time
    
    Actually respect the cache-age setting if the file already exists.

 src/plugins/gs-plugin-shell-extensions.c |   21 +++++++++++++++------
 1 files changed, 15 insertions(+), 6 deletions(-)
---
diff --git a/src/plugins/gs-plugin-shell-extensions.c b/src/plugins/gs-plugin-shell-extensions.c
index 224411b..c9a7649 100644
--- a/src/plugins/gs-plugin-shell-extensions.c
+++ b/src/plugins/gs-plugin-shell-extensions.c
@@ -668,6 +668,21 @@ gs_plugin_refresh (GsPlugin *plugin,
        if ((flags & GS_PLUGIN_REFRESH_FLAGS_METADATA) == 0)
                return TRUE;
 
+       /* check age */
+       fn = g_build_filename (g_get_user_data_dir (),
+                              "app-info",
+                              "xmls",
+                              "extensions-web.xml",
+                              NULL);
+       file = g_file_new_for_path (fn);
+       if (g_file_query_exists (file, NULL)) {
+               guint age = gs_utils_get_file_age (file);
+               if (age < cache_age) {
+                       g_debug ("%s is only %i seconds old, ignoring", fn, age);
+                       return TRUE;
+               }
+       }
+
        /* connect to gnome-shell */
        if (!gs_plugin_setup (plugin, cancellable, error))
                return FALSE;
@@ -687,14 +702,8 @@ gs_plugin_refresh (GsPlugin *plugin,
        }
 
        /* save to disk */
-       fn = g_build_filename (g_get_user_data_dir (),
-                              "app-info",
-                              "xmls",
-                              "extensions-web.xml",
-                              NULL);
        if (!gs_mkdir_parent (fn, error))
                return FALSE;
-       file = g_file_new_for_path (fn);
        g_debug ("saving to %s", fn);
        return as_store_to_file (store, file,
                                 AS_NODE_TO_XML_FLAG_ADD_HEADER |