[gnome-software/1105-gs-details-page-rating-histogram-hidden-when-being-offline] gs-plugins-odrs: Load ratings from the cache when refresh is skipped on start

[Milan Crha <mcrha src gnome org>]

commit 2663ab27c371829fe93b9fd47220f66f4985febd
Author: Milan Crha <mcrha redhat com>
Date:   Tue Dec 1 17:39:30 2020 +0100

    gs-plugins-odrs: Load ratings from the cache when refresh is skipped on start
    
    Check whether any ratings are cached and load that at least, thus
    the rating histogram at the details page can show information from the last run.
    
    Closes https://gitlab.gnome.org/GNOME/gnome-software/-/issues/1105
    Closes https://gitlab.gnome.org/GNOME/gnome-software/-/merge_requests/554

 plugins/odrs/gs-plugin-odrs.c | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)
---
diff --git a/plugins/odrs/gs-plugin-odrs.c b/plugins/odrs/gs-plugin-odrs.c
index ca834990..ec2b5b1a 100644
--- a/plugins/odrs/gs-plugin-odrs.c
+++ b/plugins/odrs/gs-plugin-odrs.c
@@ -630,8 +630,27 @@ gs_plugin_odrs_refine_ratings (GsPlugin *plugin,
 
        locker = g_mutex_locker_new (&priv->ratings_mutex);
 
-       if (priv->ratings == NULL)
-               return TRUE;
+       if (!priv->ratings) {
+               g_autofree gchar *cache_filename = NULL;
+
+               g_clear_pointer (&locker, g_mutex_locker_free);
+
+               /* Load from the local cache, if available, when in offline or
+                  when refresh/download disabled on start */
+               cache_filename = gs_utils_get_cache_filename ("odrs",
+                                                             "ratings.json",
+                                                             GS_UTILS_CACHE_FLAG_WRITEABLE,
+                                                             error);
+
+               if (!cache_filename ||
+                   !gs_plugin_odrs_load_ratings (plugin, cache_filename, NULL))
+                       return TRUE;
+
+               locker = g_mutex_locker_new (&priv->ratings_mutex);
+
+               if (!priv->ratings)
+                       return TRUE;
+       }
 
        for (guint i = 0; i < reviewable_ids->len; i++) {
                const gchar *id = g_ptr_array_index (reviewable_ids, i);