[gnome-todo] task-list-view: only add and remove what's necessary

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 6de3d6ebae038f2a29cbb12bded1eb43d80b947b
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Wed Oct 5 21:27:58 2016 -0300

    task-list-view: only add and remove what's necessary
    
    Instead of blindly clearing the entire list and readding everything,
    be smart and only remove what's already there, and add what's not in
    there.

 src/gtd-task-list-view.c |   43 ++++++++++++++++++++++++++++---------------
 1 files changed, 28 insertions(+), 15 deletions(-)
---
diff --git a/src/gtd-task-list-view.c b/src/gtd-task-list-view.c
index 819de15..af65aa8 100644
--- a/src/gtd-task-list-view.c
+++ b/src/gtd-task-list-view.c
@@ -488,22 +488,25 @@ gtd_task_list_view__listbox_sort_func (GtdTaskRow *row1,
 }
 
 static void
-gtd_task_list_view__clear_list (GtdTaskListView *view)
+remove_task (GtdTaskListView *view,
+             GtdTask         *task)
 {
+  GtdTaskListViewPrivate *priv = view->priv;
   GList *children;
   GList *l;
 
-  g_return_if_fail (GTD_IS_TASK_LIST_VIEW (view));
-
-  view->priv->complete_tasks = 0;
   gtd_arrow_frame_set_row (view->priv->arrow_frame, NULL);
 
   children = gtk_container_get_children (GTK_CONTAINER (view->priv->listbox));
 
   for (l = children; l != NULL; l = l->next)
     {
-      if (l->data != view->priv->new_task_row)
+      if (l->data != priv->new_task_row &&
+          gtd_task_row_get_task (l->data) == task)
         {
+          if (gtd_task_get_complete (task))
+            priv->complete_tasks--;
+
           g_signal_handlers_disconnect_by_func (gtd_task_row_get_task (l->data),
                                                 gtd_task_list_view__task_completed,
                                                 view);
@@ -511,8 +514,8 @@ gtd_task_list_view__clear_list (GtdTaskListView *view)
         }
     }
 
-  gtk_revealer_set_reveal_child (view->priv->revealer, FALSE);
-  gtk_revealer_set_reveal_child (view->priv->edit_revealer, FALSE);
+  gtk_revealer_set_reveal_child (priv->revealer, FALSE);
+  gtk_revealer_set_reveal_child (priv->edit_revealer, FALSE);
 
   g_list_free (children);
 }
@@ -982,20 +985,27 @@ void
 gtd_task_list_view_set_list (GtdTaskListView *view,
                              GList           *list)
 {
-  GList *l;
+  GtdTaskListViewPrivate *priv;
+  GList *l, *old_list;
 
   g_return_if_fail (GTD_IS_TASK_LIST_VIEW (view));
 
-  if (view->priv->list)
-    g_list_free (view->priv->list);
-
-  /* clear previous tasks */
-  gtd_task_list_view__clear_list (view);
+  priv = view->priv;
+  old_list = priv->list;
 
-  view->priv->list = g_list_copy (list);
+  /* Remove the tasks that are in the current list, but not in the new list */
+  for (l = old_list; l != NULL; l = l->next)
+    {
+      if (!g_list_find (list, l->data))
+        remove_task (view, l->data);
+    }
 
-  for (l = view->priv->list; l != NULL; l = l->next)
+  /* Add the tasks that are in the new list, but not in the current list */
+  for (l = list; l != NULL; l = l->next)
     {
+      if (g_list_find (old_list, l->data))
+        continue;
+
       gtd_task_list_view__add_task (view, l->data);
 
       g_signal_connect (l->data,
@@ -1004,6 +1014,9 @@ gtd_task_list_view_set_list (GtdTaskListView *view,
                         view);
     }
 
+  g_list_free (old_list);
+  priv->list = g_list_copy (list);
+
   /* Check if it should show the empty state */
   gtd_task_list_view__update_empty_state (view);
 }