From 215f60e450e7f09ddea002f25ae29f3888921041 Mon Sep 17 00:00:00 2001
From: Matthias Clasen <mclasen@redhat.com>
Date: Tue, 23 May 2023 13:49:04 -0400
Subject: [PATCH] listitemmanager: Listen to sections-changed

And recreate header and footer tiles as needed.

This commit was tested using a sortlistmodel, changing
the section sorter from sorting only by first char
to sorting by the first two chars, which changes
the number of sections, but leaves the alphabetic
order of items unchanged.
---
 gtk/gtklistitemmanager.c | 69 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)

diff --git a/gtk/gtklistitemmanager.c b/gtk/gtklistitemmanager.c
index aa5c9b1bf8..3c63c70ac3 100644
--- a/gtk/gtklistitemmanager.c
+++ b/gtk/gtklistitemmanager.c
@@ -1565,6 +1565,67 @@ gtk_list_item_manager_model_items_changed_cb (GListModel         *model,
   gtk_widget_queue_resize (self->widget);
 }
 
+static void
+gtk_list_item_manager_model_sections_changed_cb (GListModel         *model,
+                                                 guint               position,
+                                                 guint               n_items,
+                                                 GtkListItemManager *self)
+{
+  GtkListItemChange change;
+  GtkListTile *tile, *header;
+  guint offset;
+
+  if (!gtk_list_item_manager_has_sections (self))
+    return;
+
+  gtk_list_item_change_init (&change);
+
+  tile = gtk_list_item_manager_get_nth (self, position, &offset);
+  header = gtk_list_tile_get_header (self, tile);
+  gtk_list_item_change_clear_header (&change, &header->widget);
+  gtk_list_tile_set_type (header, GTK_LIST_TILE_UNMATCHED_HEADER);
+
+  n_items -= MIN (n_items, position - offset);
+  while (n_items > 0)
+    {
+      switch (tile->type)
+        {
+        case GTK_LIST_TILE_HEADER:
+        case GTK_LIST_TILE_UNMATCHED_HEADER:
+          gtk_list_item_change_clear_header (&change, &tile->widget);
+          gtk_list_tile_set_type (tile, GTK_LIST_TILE_REMOVED);
+          break;
+
+        case GTK_LIST_TILE_FOOTER:
+        case GTK_LIST_TILE_UNMATCHED_FOOTER:
+          gtk_list_tile_set_type (tile, GTK_LIST_TILE_REMOVED);
+          break;
+
+        case GTK_LIST_TILE_ITEM:
+          n_items -= MIN (n_items, tile->n_items);
+          break;
+
+        case GTK_LIST_TILE_REMOVED:
+        default:
+          g_assert_not_reached ();
+          break;
+        }
+
+      tile = gtk_list_tile_get_next_skip (tile);
+    }
+
+  if (!gtk_list_tile_is_footer (tile))
+    tile = gtk_list_tile_get_footer (self, tile);
+
+  gtk_list_tile_set_type (tile, GTK_LIST_TILE_UNMATCHED_FOOTER);
+
+  gtk_list_item_manager_ensure_items (self, &change, G_MAXUINT, 0);
+
+  gtk_list_item_change_finish (&change);
+
+  gtk_widget_queue_resize (GTK_WIDGET (self->widget));
+}
+
 static void
 gtk_list_item_manager_model_selection_changed_cb (GListModel         *model,
                                                   guint               position,
@@ -1624,6 +1685,9 @@ gtk_list_item_manager_clear_model (GtkListItemManager *self)
   g_signal_handlers_disconnect_by_func (self->model,
                                         gtk_list_item_manager_model_items_changed_cb,
                                         self);
+  g_signal_handlers_disconnect_by_func (self->model,
+                                        gtk_list_item_manager_model_sections_changed_cb,
+                                        self);
   g_clear_object (&self->model);
 
   gtk_list_item_manager_gc_tiles (self);
@@ -1682,6 +1746,11 @@ gtk_list_item_manager_set_model (GtkListItemManager *self,
                         "selection-changed",
                         G_CALLBACK (gtk_list_item_manager_model_selection_changed_cb),
                         self);
+      if (GTK_IS_SECTION_MODEL (model))
+        g_signal_connect (model,
+                          "sections-changed",
+                          G_CALLBACK (gtk_list_item_manager_model_sections_changed_cb),
+                          self);
 
       gtk_list_item_change_init (&change);
       gtk_list_item_manager_add_items (self, &change, 0, g_list_model_get_n_items (G_LIST_MODEL (model)));
-- 
2.30.2