[gnome-todo] task-model: Use GtkFlattenListModel internally

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

commit 234d51293eda5a957fdab1a7bbe44db9c6408743
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Thu Jul 4 11:42:05 2019 -0300

    task-model: Use GtkFlattenListModel internally
    
    We still need GtdTaskModel to return GTD_TYPE_TASK as the
    list model type, but GtkFlattenListModel helps reducing a
    lot of the code there.

 src/models/gtd-task-model.c | 181 ++++----------------------------------------
 1 file changed, 14 insertions(+), 167 deletions(-)
---
diff --git a/src/models/gtd-task-model.c b/src/models/gtd-task-model.c
index 9943b7d..e9c331b 100644
--- a/src/models/gtd-task-model.c
+++ b/src/models/gtd-task-model.c
@@ -32,7 +32,7 @@ struct _GtdTaskModel
 {
   GObject             parent;
 
-  GtdListStore       *lists;
+  GtkFlattenListModel *model;
 
   guint               number_of_tasks;
 
@@ -54,136 +54,21 @@ enum
 static GParamSpec *properties [N_PROPS];
 
 
-/*
- * Auxiliary methods
- */
-
-static guint
-find_task_position_at_list_position (GtdTaskModel *self,
-                                     guint         position)
-{
-  GListModel *tasklists;
-  guint offset = 0;
-  guint i;
-
-  tasklists = gtd_manager_get_task_lists_model (self->manager);
-
-  g_assert (g_list_model_get_n_items (tasklists) > position);
-
-  for (i = 0; i < position; i++)
-    {
-      g_autoptr (GListModel) tasklist = g_list_model_get_item (tasklists, i);
-      offset += g_list_model_get_n_items (tasklist);
-    }
-
-  return offset;
-}
-
-
 /*
  * Callbacks
  */
 
 static void
-on_task_list_items_changed_cb (GtdTaskList  *tasklist,
-                               guint         position,
-                               guint         n_removed,
-                               guint         n_added,
-                               GtdTaskModel *self)
+on_model_items_changed_cb (GListModel   *model,
+                           guint         position,
+                           guint         n_removed,
+                           guint         n_added,
+                           GtdTaskModel *self)
 {
-  guint task_position;
-  guint list_position;
-  gint diff;
-
-  list_position = gtd_list_store_get_item_position (self->lists, tasklist);
-  task_position = find_task_position_at_list_position (self, list_position) + position;
-
-  diff = (gint) n_added - (gint) n_removed;
-
-  self->number_of_tasks += diff;
-
-  g_list_model_items_changed (G_LIST_MODEL (self), task_position, n_removed, n_added);
-
-  GTD_TRACE_MSG ("Task list changed with position=%u, n_removed=%u, n_added=%u",
-                 task_position,
-                 n_removed,
-                 n_added);
-}
-
-static void
-on_manager_items_changed_cb (GListModel   *model,
-                             guint         position,
-                             guint         n_removed,
-                             guint         n_added,
-                             GtdTaskModel *self)
-{
-  guint offset;
-
   GTD_TRACE_MSG ("Child model changed with position=%u, n_removed=%u, n_added=%u", position, n_removed, 
n_added);
 
-  offset = find_task_position_at_list_position (self, position);
-
-  if (n_removed > 0)
-    {
-      guint n_removed_tasks = 0;
-      guint i;
-
-      for (i = 0; i < n_removed; i++)
-        {
-          g_autoptr (GtdTaskList) list = NULL;
-
-          list = g_list_model_get_item (G_LIST_MODEL (self->lists), position + i);
-          g_signal_handlers_disconnect_by_func (list, on_task_list_items_changed_cb, self);
-
-          n_removed_tasks += g_list_model_get_n_items (G_LIST_MODEL (list));
-        }
+  g_list_model_items_changed (G_LIST_MODEL (self), position, n_removed, n_added);
 
-      self->number_of_tasks -= n_removed_tasks;
-
-      g_list_model_items_changed (G_LIST_MODEL (self),
-                                  offset,
-                                  n_removed_tasks,
-                                  0);
-
-      GTD_TRACE_MSG ("Removed %u items at %u", n_removed_tasks, offset);
-    }
-
-  if (n_added > 0)
-    {
-      GListModel *tasklists;
-      guint n_added_tasks = 0;
-      guint i;
-
-      tasklists = gtd_manager_get_task_lists_model (self->manager);
-
-      for (i = 0; i < n_added; i++)
-        {
-          g_autoptr (GtdTaskList) list = NULL;
-          guint n_tasks;
-
-          list = g_list_model_get_item (tasklists, position + i);
-          n_tasks = g_list_model_get_n_items (G_LIST_MODEL (list));
-
-          g_signal_connect_object (list,
-                                   "items-changed",
-                                   G_CALLBACK (on_task_list_items_changed_cb),
-                                   self,
-                                   0);
-
-          n_added_tasks += n_tasks;
-
-          gtd_list_store_insert (self->lists, position + i, list);
-        }
-
-      self->number_of_tasks += n_added_tasks;
-
-      g_list_model_items_changed (G_LIST_MODEL (self),
-                                  offset,
-                                  0,
-                                  n_added_tasks);
-
-      GTD_TRACE_MSG ("Added %u tasks at %u", n_added_tasks, offset);
-    }
 }
 
 
@@ -196,31 +81,8 @@ gtd_task_model_get_item (GListModel *model,
                          guint       position)
 {
   GtdTaskModel *self = (GtdTaskModel*) model;
-  GListModel *tasklists;
-  guint current_item = 0;
-  guint i;
 
-  tasklists = gtd_manager_get_task_lists_model (self->manager);
-
-  for (i = 0; i < g_list_model_get_n_items (tasklists); i++)
-    {
-      g_autoptr (GtdTaskList) tasklist = NULL;
-      guint n_items;
-
-      tasklist = g_list_model_get_item (tasklists, i);
-      n_items = g_list_model_get_n_items (G_LIST_MODEL (tasklist));
-
-      if (current_item + n_items > position)
-        {
-          guint list_position = position - current_item;
-
-          return g_list_model_get_item (G_LIST_MODEL (tasklist), list_position);
-        }
-
-      current_item += n_items;
-    }
-
-  return NULL;
+  return g_list_model_get_item (G_LIST_MODEL (self->model), position);
 }
 
 static guint
@@ -228,7 +90,7 @@ gtd_task_model_get_n_items (GListModel *model)
 {
   GtdTaskModel *self = (GtdTaskModel*) model;
 
-  return self->number_of_tasks;
+  return g_list_model_get_n_items (G_LIST_MODEL (self->model));
 }
 
 static GType
@@ -256,7 +118,7 @@ gtd_task_model_finalize (GObject *object)
   GtdTaskModel *self = (GtdTaskModel *)object;
 
   g_clear_object (&self->manager);
-  g_clear_object (&self->lists);
+  g_clear_object (&self->model);
 
   G_OBJECT_CLASS (gtd_task_model_parent_class)->finalize (object);
 }
@@ -267,32 +129,17 @@ gtd_task_model_constructed (GObject *object)
 {
   GtdTaskModel *self = (GtdTaskModel *)object;
   GListModel *model;
-  guint i;
 
   g_assert (self->manager != NULL);
 
   model = gtd_manager_get_task_lists_model (self->manager);
 
-  g_signal_connect_object (model,
+  g_signal_connect_object (self->model,
                            "items-changed",
-                           G_CALLBACK (on_manager_items_changed_cb),
+                           G_CALLBACK (on_model_items_changed_cb),
                            self,
                            0);
-
-
-  for (i = 0; i < g_list_model_get_n_items (model); i++)
-    {
-      g_autoptr (GListModel) list = g_list_model_get_item (model, i);
-
-      gtd_list_store_insert (self->lists, i, list);
-      g_signal_connect_object (list,
-                               "items-changed",
-                               G_CALLBACK (on_task_list_items_changed_cb),
-                               self,
-                               0);
-
-      self->number_of_tasks += g_list_model_get_n_items (list);
-    }
+  gtk_flatten_list_model_set_model (self->model, model);
 
   G_OBJECT_CLASS (gtd_task_model_parent_class)->constructed (object);
 }
@@ -358,7 +205,7 @@ gtd_task_model_class_init (GtdTaskModelClass *klass)
 static void
 gtd_task_model_init (GtdTaskModel *self)
 {
-  self->lists = gtd_list_store_new (GTD_TYPE_TASK_LIST);
+  self->model = gtk_flatten_list_model_new (GTD_TYPE_OBJECT, NULL);
 }
 
 GtdTaskModel*