[gnome-software] odrs: Use a JsonObjectIter to save memory

[Richard Hughes <rhughes src gnome org>]

commit 8be622423a292b6d20e66b3d47b7f559a7788926
Author: Philip Withnall <withnall endlessm com>
Date:   Mon Jun 1 18:20:46 2020 +0100

    odrs: Use a JsonObjectIter to save memory
    
    `json_object_get_members()` allocates a linked list of all the members —
    in this case, that’s around 4100 elements in the list.
    
    Use a `JsonObjectIter` to iterate directly on the internal
    representation of the object in json-glib, to save on allocations. This
    saves around 100KB of `GList` allocations.
    
    Signed-off-by: Philip Withnall <withnall endlessm com>

 plugins/odrs/gs-plugin-odrs.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)
---
diff --git a/plugins/odrs/gs-plugin-odrs.c b/plugins/odrs/gs-plugin-odrs.c
index bcc34613..5bb70626 100644
--- a/plugins/odrs/gs-plugin-odrs.c
+++ b/plugins/odrs/gs-plugin-odrs.c
@@ -185,8 +185,10 @@ gs_plugin_odrs_load_ratings (GsPlugin *plugin, const gchar *fn, GError **error)
        GsPluginData *priv = gs_plugin_get_data (plugin);
        JsonNode *json_root;
        JsonObject *json_item;
-       g_autoptr(GList) apps = NULL;
        g_autoptr(JsonParser) json_parser = NULL;
+       const gchar *app_id;
+       JsonNode *json_app_node;
+       JsonObjectIter iter;
        g_autoptr(GArray) new_ratings = NULL;
        g_autoptr(GMutexLocker) locker = NULL;
 
@@ -221,11 +223,14 @@ gs_plugin_odrs_load_ratings (GsPlugin *plugin, const gchar *fn, GError **error)
        g_array_set_clear_func (new_ratings, (GDestroyNotify) rating_clear);
 
        /* parse each app */
-       apps = json_object_get_members (json_item);
-       for (GList *l = apps; l != NULL; l = l->next) {
-               const gchar *app_id = (const gchar *) l->data;
-               JsonObject *json_app = json_object_get_object_member (json_item, app_id);
+       json_object_iter_init (&iter, json_item);
+       while (json_object_iter_next (&iter, &app_id, &json_app_node)) {
                GsOdrsRating rating;
+               JsonObject *json_app;
+
+               if (!JSON_NODE_HOLDS_OBJECT (json_app_node))
+                       continue;
+               json_app = json_node_get_object (json_app_node);
 
                if (gs_plugin_odrs_load_ratings_for_app (json_app, app_id, &rating))
                        g_array_append_val (new_ratings, rating);