[gtk+] treeview: Handle the case where the cursor row gets deleted

[Benjamin Otte <otte src gnome org>]

commit 1a2932ba2915c34171581a85afba39311e9c3ac6
Author: Benjamin Otte <otte redhat com>
Date:   Sat Dec 10 04:48:12 2011 +0100

    treeview: Handle the case where the cursor row gets deleted
    
    Previously, the cursor would just become invalid, which used to
    reselect the first row in the treeview later on (without a
    cursor-changed signal). This leads to a crash now with the recent
    refactorings.
    
    The patch is longer than I'd like it to be, but the situation is kinda
    complicated, because we want to make sure to move the cursor to a good
    row. It works like this:
    1) From the deleted row, search forward for the first row that is not
       going to be deleted and is not a separator.
    2) If no such row exists, search backwards for a row that is not a
       separator.
    3) If no such node exists, clear the cursor.

 gtk/gtktreeview.c |   64 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 62 insertions(+), 2 deletions(-)
---
diff --git a/gtk/gtktreeview.c b/gtk/gtktreeview.c
index 9841248..165a9e3 100644
--- a/gtk/gtktreeview.c
+++ b/gtk/gtktreeview.c
@@ -8977,7 +8977,9 @@ gtk_tree_view_row_deleted (GtkTreeModel *model,
   GtkRBTree *tree;
   GtkRBNode *node;
   GList *list;
-  gint selection_changed = FALSE;
+  gboolean selection_changed = FALSE, cursor_changed = FALSE;
+  GtkRBTree *cursor_tree = NULL;
+  GtkRBNode *cursor_node = NULL;
   GtkStyleContext *context;
 
   g_return_if_fail (path != NULL);
@@ -9005,6 +9007,52 @@ gtk_tree_view_row_deleted (GtkTreeModel *model,
   /* Cancel editting if we've started */
   gtk_tree_view_stop_editing (tree_view, TRUE);
 
+  /* If the cursor row got deleted, move the cursor to the next row */
+  if (tree_view->priv->cursor_node &&
+      (tree_view->priv->cursor_node == node ||
+       (node->children &&  _gtk_rbtree_contains (node->children, tree_view->priv->cursor_tree))))
+    {
+      GtkTreePath *cursor_path;
+
+      cursor_tree = tree;
+      cursor_node = _gtk_rbtree_next (tree, node);
+      /* find the first node that is not going to be deleted */
+      while (cursor_node == NULL && cursor_tree->parent_tree)
+        {
+          cursor_node = _gtk_rbtree_next (cursor_tree->parent_tree,
+                                          cursor_tree->parent_node);
+          cursor_tree = cursor_tree->parent_tree;
+        }
+
+      if (cursor_node != NULL)
+        cursor_path = _gtk_tree_path_new_from_rbtree (cursor_tree, cursor_node);
+      else
+        cursor_path = NULL;
+
+      if (cursor_path == NULL ||
+          ! search_first_focusable_path (tree_view, &cursor_path, TRUE, 
+                                         &cursor_tree, &cursor_node))
+        {
+          /* It looks like we reached the end of the view without finding
+           * a focusable row.  We will step backwards to find the last
+           * focusable row.
+           */
+          _gtk_rbtree_prev_full (tree, node, &cursor_tree, &cursor_node);
+          if (cursor_node)
+            {
+              cursor_path = _gtk_tree_path_new_from_rbtree (cursor_tree, cursor_node);
+              if (! search_first_focusable_path (tree_view, &cursor_path, FALSE,
+                                                 &cursor_tree, &cursor_node))
+                cursor_node = NULL;
+              gtk_tree_path_free (cursor_path);
+            }
+        }
+      else if (cursor_path)
+        gtk_tree_path_free (cursor_path);
+
+      cursor_changed = TRUE;
+    }
+
   if (tree_view->priv->destroy_count_func)
     {
       gint child_count = 0;
@@ -9041,7 +9089,19 @@ gtk_tree_view_row_deleted (GtkTreeModel *model,
 
   gtk_widget_queue_resize (GTK_WIDGET (tree_view));
 
-  if (selection_changed)
+  if (cursor_changed)
+    {
+      if (cursor_node)
+        {
+          GtkTreePath *cursor_path = _gtk_tree_path_new_from_rbtree (cursor_tree, cursor_node);
+          tree_view->priv->cursor_node = NULL;
+          gtk_tree_view_real_set_cursor (tree_view, cursor_path, TRUE, FALSE);
+          gtk_tree_path_free (cursor_path);
+        }
+      else
+        gtk_tree_view_real_set_cursor (tree_view, NULL, TRUE, FALSE);
+    }
+  else if (selection_changed)
     g_signal_emit_by_name (tree_view->priv->selection, "changed");
 }