[gnome-photos] preview-nav-buttons: Track the active item across changes to the model

[Debarshi Ray <debarshir src gnome org>]

commit b26db443c9f70abbc3f2345a050b6f1de36b4d3e
Author: Debarshi Ray <debarshir gnome org>
Date:   Mon Oct 26 14:42:29 2015 +0100

    preview-nav-buttons: Track the active item across changes to the model
    
    Deleting from the preview will cause modifications to the PreviewModel
    and we should not lose track of the active item due to this.
    Therefore, use a GtkTreeRowReference instead of a GtkTreePath to
    denote the active item.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=733660

 src/photos-preview-nav-buttons.c |   49 ++++++++++++++++++++++++++-----------
 1 files changed, 34 insertions(+), 15 deletions(-)
---
diff --git a/src/photos-preview-nav-buttons.c b/src/photos-preview-nav-buttons.c
index c78a895..e72d95f 100644
--- a/src/photos-preview-nav-buttons.c
+++ b/src/photos-preview-nav-buttons.c
@@ -42,7 +42,7 @@ struct _PhotosPreviewNavButtonsPrivate
   GAction *load_previous;
   GtkGesture *tap_gesture;
   GtkTreeModel *model;
-  GtkTreePath *current_path;
+  GtkTreeRowReference *current_row;
   GtkWidget *next_widget;
   GtkWidget *overlay;
   GtkWidget *prev_widget;
@@ -72,7 +72,7 @@ photos_preview_nav_buttons_fade_in_button (PhotosPreviewNavButtons *self, GtkWid
 {
   PhotosPreviewNavButtonsPrivate *priv = self->priv;
 
-  if (priv->model == NULL || priv->current_path == NULL)
+  if (priv->model == NULL || !gtk_tree_row_reference_valid (priv->current_row))
     return;
 
   gtk_widget_show_all (widget);
@@ -111,17 +111,20 @@ photos_preview_nav_buttons_update_visibility (PhotosPreviewNavButtons *self)
   PhotosPreviewNavButtonsPrivate *priv = self->priv;
   GtkTreeIter iter;
   GtkTreeIter tmp;
+  GtkTreePath *current_path = NULL;
 
   if (priv->model == NULL
-      || priv->current_path == NULL
-      || !priv->visible
-      || !gtk_tree_model_get_iter (priv->model, &iter, priv->current_path))
+      || !gtk_tree_row_reference_valid (priv->current_row)
+      || !priv->visible)
     {
       priv->enable_prev = FALSE;
       priv->enable_next = FALSE;
       goto out;
     }
 
+  current_path = gtk_tree_row_reference_get_path (priv->current_row);
+  gtk_tree_model_get_iter (priv->model, &iter, current_path);
+
   tmp = iter;
   priv->enable_prev = gtk_tree_model_iter_previous (priv->model, &tmp);
 
@@ -141,6 +144,8 @@ photos_preview_nav_buttons_update_visibility (PhotosPreviewNavButtons *self)
 
   g_simple_action_set_enabled (G_SIMPLE_ACTION (priv->load_next), priv->enable_next);
   g_simple_action_set_enabled (G_SIMPLE_ACTION (priv->load_previous), priv->enable_prev);
+
+  g_clear_pointer (&current_path, (GDestroyNotify) gtk_tree_path_free);
 }
 
 
@@ -255,7 +260,7 @@ photos_preview_nav_buttons_multi_press_stopped (PhotosPreviewNavButtons *self)
 
 
 static void
-photos_preview_nav_buttons_set_active_path (PhotosPreviewNavButtons *self)
+photos_preview_nav_buttons_set_active_path (PhotosPreviewNavButtons *self, GtkTreePath *current_path)
 {
   PhotosPreviewNavButtonsPrivate *priv = self->priv;
   GtkTreeIter child_iter;
@@ -264,9 +269,12 @@ photos_preview_nav_buttons_set_active_path (PhotosPreviewNavButtons *self)
   PhotosBaseItem *item;
   gchar *id;
 
-  if (!gtk_tree_model_get_iter (priv->model, &iter, priv->current_path))
+  if (!gtk_tree_model_get_iter (priv->model, &iter, current_path))
     return;
 
+  g_clear_pointer (&priv->current_row, (GDestroyNotify) gtk_tree_row_reference_free);
+  priv->current_row = gtk_tree_row_reference_new (priv->model, current_path);
+
   gtk_tree_model_filter_convert_iter_to_child_iter (GTK_TREE_MODEL_FILTER (priv->model), &child_iter, &iter);
   child_model = gtk_tree_model_filter_get_model (GTK_TREE_MODEL_FILTER (priv->model));
   gtk_tree_model_get (child_model, &child_iter, PHOTOS_VIEW_MODEL_URN, &id, -1);
@@ -282,13 +290,16 @@ static void
 photos_preview_nav_buttons_next (PhotosPreviewNavButtons *self)
 {
   PhotosPreviewNavButtonsPrivate *priv = self->priv;
+  GtkTreePath *current_path;
 
   if (!priv->enable_next)
     return;
 
-  gtk_tree_path_next (priv->current_path);
-  photos_preview_nav_buttons_set_active_path (self);
+  current_path = gtk_tree_row_reference_get_path (priv->current_row);
+  gtk_tree_path_next (current_path);
+  photos_preview_nav_buttons_set_active_path (self, current_path);
   photos_preview_nav_buttons_update_visibility (self);
+  gtk_tree_path_free (current_path);
 }
 
 
@@ -296,13 +307,16 @@ static void
 photos_preview_nav_buttons_previous (PhotosPreviewNavButtons *self)
 {
   PhotosPreviewNavButtonsPrivate *priv = self->priv;
+  GtkTreePath *current_path;
 
   if (!priv->enable_prev)
     return;
 
-  gtk_tree_path_prev (priv->current_path);
-  photos_preview_nav_buttons_set_active_path (self);
+  current_path = gtk_tree_row_reference_get_path (priv->current_row);
+  gtk_tree_path_prev (current_path);
+  photos_preview_nav_buttons_set_active_path (self, current_path);
   photos_preview_nav_buttons_update_visibility (self);
+  gtk_tree_path_free (current_path);
 }
 
 
@@ -328,7 +342,7 @@ photos_preview_nav_buttons_finalize (GObject *object)
   PhotosPreviewNavButtons *self = PHOTOS_PREVIEW_NAV_BUTTONS (object);
   PhotosPreviewNavButtonsPrivate *priv = self->priv;
 
-  g_clear_pointer (&priv->current_path, (GDestroyNotify) gtk_tree_path_free);
+  g_clear_pointer (&priv->current_row, (GDestroyNotify) gtk_tree_row_reference_free);
 
   G_OBJECT_CLASS (photos_preview_nav_buttons_parent_class)->finalize (object);
 }
@@ -526,11 +540,16 @@ photos_preview_nav_buttons_set_model (PhotosPreviewNavButtons *self,
   if (child_model != NULL)
     priv->model = photos_preview_model_new (child_model);
 
-  g_clear_pointer (&priv->current_path, (GDestroyNotify) gtk_tree_path_free);
+  g_clear_pointer (&priv->current_row, (GDestroyNotify) gtk_tree_row_reference_free);
+
   if (child_model != NULL && current_child_path != NULL)
     {
-      priv->current_path = gtk_tree_model_filter_convert_child_path_to_path (GTK_TREE_MODEL_FILTER 
(priv->model),
-                                                                             current_child_path);
+      GtkTreePath *current_path;
+
+      current_path = gtk_tree_model_filter_convert_child_path_to_path (GTK_TREE_MODEL_FILTER (priv->model),
+                                                                       current_child_path);
+      priv->current_row = gtk_tree_row_reference_new (priv->model, current_path);
+      gtk_tree_path_free (current_path);
     }
 }