[gtk+] GtkFileChooser: Make preview update more understandable

[Matthias Clasen <matthiasc src gnome org>]

commit f678e48a08a376cbed060b52cd9746febf44c6cc
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Oct 19 17:54:28 2014 -0400

    GtkFileChooser: Make preview update more understandable
    
    Implement Federico's suggestion:
    In single-selection mode, just use the selected row,
    In multi-selection mode, use the cursor row as long as it is
    in the selection.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=154709

 gtk/gtkfilechooserwidget.c |   45 +++++++++++++++++++++++++++++++++++++------
 1 files changed, 38 insertions(+), 7 deletions(-)
---
diff --git a/gtk/gtkfilechooserwidget.c b/gtk/gtkfilechooserwidget.c
index 404ca8d..984aaf0 100644
--- a/gtk/gtkfilechooserwidget.c
+++ b/gtk/gtkfilechooserwidget.c
@@ -496,11 +496,13 @@ static gboolean list_select_func   (GtkTreeSelection      *selection,
                                    gpointer               data);
 
 static void list_selection_changed     (GtkTreeSelection      *tree_selection,
-                                       GtkFileChooserWidget *impl);
+                                       GtkFileChooserWidget  *impl);
 static void list_row_activated         (GtkTreeView           *tree_view,
                                        GtkTreePath           *path,
                                        GtkTreeViewColumn     *column,
-                                       GtkFileChooserWidget *impl);
+                                       GtkFileChooserWidget  *impl);
+static void list_cursor_changed        (GtkTreeView           *treeview,
+                                        GtkFileChooserWidget  *impl);
 
 static void path_bar_clicked (GtkPathBar            *path_bar,
                              GFile                 *file,
@@ -6571,24 +6573,45 @@ static void
 check_preview_change (GtkFileChooserWidget *impl)
 {
   GtkFileChooserWidgetPrivate *priv = impl->priv;
-  GtkTreePath *cursor_path;
+  GtkTreePath *path;
   GFile *new_file;
   char *new_display_name;
   GtkTreeModel *model;
+  GtkTreeSelection *selection;
 
-  gtk_tree_view_get_cursor (GTK_TREE_VIEW (priv->browse_files_tree_view), &cursor_path, NULL);
   model = gtk_tree_view_get_model (GTK_TREE_VIEW (priv->browse_files_tree_view));
-  if (cursor_path)
+  selection = gtk_tree_view_get_selection (GTK_TREE_VIEW (priv->browse_files_tree_view));
+  if (gtk_tree_selection_get_mode (selection) == GTK_SELECTION_SINGLE ||
+      gtk_tree_selection_get_mode (selection) == GTK_SELECTION_BROWSE)
     {
       GtkTreeIter iter;
 
-      gtk_tree_model_get_iter (model, &iter, cursor_path);
+      if (gtk_tree_selection_get_selected (selection, NULL, &iter))
+        path = gtk_tree_model_get_path (model, &iter);
+      else
+        path = NULL;
+    }
+  else
+    {
+      gtk_tree_view_get_cursor (GTK_TREE_VIEW (priv->browse_files_tree_view), &path, NULL);
+      if (path && !gtk_tree_selection_path_is_selected (selection, path))
+        {
+          gtk_tree_path_free (path);
+          path = NULL;
+        }
+    }
+
+  if (path)
+    {
+      GtkTreeIter iter;
+
+      gtk_tree_model_get_iter (model, &iter, path);
       gtk_tree_model_get (model, &iter,
                           MODEL_COL_FILE, &new_file,
                           MODEL_COL_NAME, &new_display_name,
                           -1);
       
-      gtk_tree_path_free (cursor_path);
+      gtk_tree_path_free (path);
     }
   else
     {
@@ -6696,6 +6719,13 @@ list_selection_changed (GtkTreeSelection      *selection,
   g_signal_emit_by_name (impl, "selection-changed", 0);
 }
 
+static void
+list_cursor_changed (GtkTreeView          *list,
+                     GtkFileChooserWidget *impl)
+{
+  check_preview_change (impl);
+}
+
 /* Callback used when a row in the file list is activated */
 static void
 list_row_activated (GtkTreeView           *tree_view,
@@ -7382,6 +7412,7 @@ gtk_file_chooser_widget_class_init (GtkFileChooserWidgetClass *class)
   gtk_widget_class_bind_template_callback (widget_class, list_row_activated);
   gtk_widget_class_bind_template_callback (widget_class, file_list_drag_motion_cb);
   gtk_widget_class_bind_template_callback (widget_class, list_selection_changed);
+  gtk_widget_class_bind_template_callback (widget_class, list_cursor_changed);
   gtk_widget_class_bind_template_callback (widget_class, renderer_editing_canceled_cb);
   gtk_widget_class_bind_template_callback (widget_class, renderer_edited_cb);
   gtk_widget_class_bind_template_callback (widget_class, filter_combo_changed);