[gnome-software] Make gs_app_list_filter_duplicates not change app order.

[Robert Ancell <rancell src gnome org>]

commit a0d8f2f6c9de5f145f845c6fd2723d9d6d3450ef
Author: Robert Ancell <robert ancell canonical com>
Date:   Fri Aug 18 16:15:51 2017 +1200

    Make gs_app_list_filter_duplicates not change app order.
    
    Previously filter_duplicates would put non-duplicate apps back in an
    order determinted by their storage in a GHashTable. This change
    refactors the function so the order is retained.

 lib/gs-app-list.c |   38 +++++++++++++++++++-------------------
 1 files changed, 19 insertions(+), 19 deletions(-)
---
diff --git a/lib/gs-app-list.c b/lib/gs-app-list.c
index 3b595df..49f682f 100644
--- a/lib/gs-app-list.c
+++ b/lib/gs-app-list.c
@@ -469,6 +469,7 @@ gs_app_list_randomize (GsAppList *list)
 /**
  * gs_app_list_filter_duplicates:
  * @list: A #GsAppList
+ * @flags: a #GsAppListFilterFlags, e.g. GS_APP_LIST_FILTER_KEY_ID
  *
  * Filter any duplicate applications from the list.
  *
@@ -478,17 +479,16 @@ void
 gs_app_list_filter_duplicates (GsAppList *list, GsAppListFilterFlags flags)
 {
        g_autoptr(GHashTable) hash = NULL;
-       g_autoptr(GList) values = NULL;
-       g_autoptr(GPtrArray) apps_no_id = NULL;
+       g_autoptr(GHashTable) kept_apps = NULL;
+       g_autoptr(GsAppList) old = NULL;
        g_autoptr(GMutexLocker) locker = g_mutex_locker_new (&list->mutex);
 
        g_return_if_fail (GS_IS_APP_LIST (list));
 
        /* a hash table to hold apps with unique app ids */
-       hash = g_hash_table_new_full (g_str_hash, g_str_equal,
-                                     g_free, (GDestroyNotify) g_object_unref);
-       /* an array to hold apps that have NULL app ids */
-       apps_no_id = g_ptr_array_new_with_free_func ((GDestroyNotify) g_object_unref);
+       hash = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, NULL);
+       /* a hash table containing apps we want to keep */
+       kept_apps = g_hash_table_new (g_direct_hash, g_direct_equal);
 
        for (guint i = 0; i < list->array->len; i++) {
                GsApp *app;
@@ -519,7 +519,7 @@ gs_app_list_filter_duplicates (GsAppList *list, GsAppListFilterFlags flags)
                if (key->len == 0) {
                        g_autofree gchar *str = gs_app_to_string (app);
                        g_debug ("adding without deduplication as no app key: %s", str);
-                       g_ptr_array_add (apps_no_id, g_object_ref (app));
+                       g_hash_table_add (kept_apps, app);
                        continue;
                }
                found = g_hash_table_lookup (hash, key->str);
@@ -527,7 +527,8 @@ gs_app_list_filter_duplicates (GsAppList *list, GsAppListFilterFlags flags)
                        g_debug ("found new %s", key->str);
                        g_hash_table_insert (hash,
                                             g_strdup (key->str),
-                                            g_object_ref (app));
+                                            app);
+                       g_hash_table_add (kept_apps, app);
                        continue;
                }
 
@@ -541,7 +542,9 @@ gs_app_list_filter_duplicates (GsAppList *list, GsAppListFilterFlags flags)
                                         gs_app_get_priority (found));
                                g_hash_table_insert (hash,
                                                     g_strdup (key->str),
-                                                    g_object_ref (app));
+                                                    app);
+                               g_hash_table_remove (kept_apps, found);
+                               g_hash_table_add (kept_apps, app);
                                continue;
                        }
                        g_debug ("ignoring worse duplicate %s (priority %u > %u)",
@@ -554,18 +557,15 @@ gs_app_list_filter_duplicates (GsAppList *list, GsAppListFilterFlags flags)
                continue;
        }
 
-       /* add back the best results to the existing list */
+       /* deep copy to a temp list and clear the current one */
+       old = gs_app_list_copy (list);
        gs_app_list_remove_all_safe (list);
-       values = g_hash_table_get_values (hash);
-       for (GList *l = values; l != NULL; l = l->next) {
-               GsApp *app = GS_APP (l->data);
-               gs_app_list_add_safe (list, app);
-       }
 
-       /* add back apps with NULL app ids to the existing list */
-       for (guint i = 0; i < apps_no_id->len; i++) {
-               GsApp *app = g_ptr_array_index (apps_no_id, i);
-               gs_app_list_add_safe (list, app);
+       /* add back the apps we want to keep */
+       for (guint i = 0; i < old->array->len; i++) {
+               GsApp *app = gs_app_list_index (old, i);
+               if (g_hash_table_contains (kept_apps, app))
+                       gs_app_list_add_safe (list, app);
        }
 }