iterate over a model and remove rows

[Benoît Dejean <benoit placenet org>]

Hello,

I'd like to know if it is safe to walk over a model and remove rows at
the same time. I'm doing this in gnome-system-monitor in many places.

Two examples:

The first function walks a list_store and removes some rows.
But i can see that multiple passes are required to drop all the old
rows, i.e. it is necessary to walk the list again to find new elements.
For example, if the list's size is ~100, a dozen of walks are required.

static void
remove_old_disks(GtkTreeModel *model, [...])
{
  GtkTreeIter iter;

  if (!gtk_tree_model_get_iter_first(model, &iter))
    return;

  do {
    char *dir;
    guint i;
    gboolean found;

    gtk_tree_model_get(model, &iter,
                       DISK_DIR, &dir,
                       -1);

    found = [...];

    if (!found) {
      if (!gtk_list_store_remove(GTK_LIST_STORE(model), &iter))
        break;
      else
        continue; // FIXME: leaks dir
    }

    g_free(dir);

  } while (gtk_tree_model_iter_next(model, &iter));
}


Second example: recursively trim some branches in a tree_store.
This code seems to work, but may be it is silently corrupting memory.

template<typename List>
static void
remove_info_from_tree (ProcData *procdata, GtkTreeModel *model,
                       ProcInfo *current, [...])
{
  GtkTreeIter child_node;

  while (gtk_tree_model_iter_children(model, &child_node,
&current->node)) {
    ProcInfo *child = 0;
    gtk_tree_model_get(model, &child_node, COL_POINTER, &child, -1);
    remove_info_from_tree(procdata, model, child, [...]);
  }

  g_assert(not gtk_tree_model_iter_has_child(model, &current->node));

  gtk_tree_store_remove(GTK_TREE_STORE(model), &current->node);
}

Thank you.
-- 
BenoÃt Dejean
GNOME http://www.gnomefr.org/
LibGTop http://directory.fsf.org/libgtop.html