/* gtktreesortable.h
 * Copyright (C) 2001  Red Hat, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library. If not, see <http://www.gnu.org/licenses/>.
 */

#if !defined (__GTK_H_INSIDE__) && !defined (GTK_COMPILATION)
#error "Only <gtk/gtk.h> can be included directly."
#endif

#ifndef __GTK_TREE_SORTABLE_H__
#define __GTK_TREE_SORTABLE_H__


#include <gtk/gtkenums.h>
#include <gtk/gtktreemodel.h>


G_BEGIN_DECLS

#define GTK_TYPE_TREE_SORTABLE            (gtk_tree_sortable_get_type ())
#define GTK_TREE_SORTABLE(obj)            (G_TYPE_CHECK_INSTANCE_CAST ((obj), GTK_TYPE_TREE_SORTABLE, GtkTreeSortable))
#define GTK_TREE_SORTABLE_CLASS(obj)      (G_TYPE_CHECK_CLASS_CAST ((obj), GTK_TYPE_TREE_SORTABLE, GtkTreeSortableIface))
#define GTK_IS_TREE_SORTABLE(obj)         (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GTK_TYPE_TREE_SORTABLE))
#define GTK_TREE_SORTABLE_GET_IFACE(obj)  (G_TYPE_INSTANCE_GET_INTERFACE ((obj), GTK_TYPE_TREE_SORTABLE, GtkTreeSortableIface))

enum {
  GTK_TREE_SORTABLE_DEFAULT_SORT_COLUMN_ID = -1,
  GTK_TREE_SORTABLE_UNSORTED_SORT_COLUMN_ID = -2
};

typedef struct _GtkTreeSortable      GtkTreeSortable; /* Dummy typedef */
typedef struct _GtkTreeSortableIface GtkTreeSortableIface;

/**
 * GtkTreeIterCompareFunc:
 * @model: The #GtkTreeModel the comparison is within
 * @a: A #GtkTreeIter in @model
 * @b: Another #GtkTreeIter in @model
 * @user_data: Data passed when the compare func is assigned e.g. by
 *  gtk_tree_sortable_set_sort_func()
 *
 * A GtkTreeIterCompareFunc should return a negative integer, zero, or a positive
 * integer if @a sorts before @b, @a sorts with @b, or @a sorts after @b
 * respectively. If two iters compare as equal, their order in the sorted model
 * is undefined. In order to ensure that the #GtkTreeSortable behaves as
 * expected, the GtkTreeIterCompareFunc must define a partial order on
 * the model, i.e. it must be reflexive, antisymmetric and transitive.
 *
 * For example, if @model is a product catalogue, then a compare function
 * for the "price" column could be one which returns
 * <literal>price_of(@a) - price_of(@b)</literal>.
 *
 * Returns: a negative integer, zero or a positive integer depending on whether
 *   @a sorts before, with or after @b
 */
typedef gint (* GtkTreeIterCompareFunc) (GtkTreeModel *model,
					 GtkTreeIter  *a,
					 GtkTreeIter  *b,
					 gpointer      user_data);


struct _GtkTreeSortableIface
{
  GTypeInterface g_iface;

  /* signals */
  void     (* sort_column_changed)   (GtkTreeSortable        *sortable);

  /* virtual table */
  gboolean (* get_sort_column_id)    (GtkTreeSortable        *sortable,
				      gint                   *sort_column_id,
				      GtkSortType            *order);
  void     (* set_sort_column_id)    (GtkTreeSortable        *sortable,
				      gint                    sort_column_id,
				      GtkSortType             order);
  void     (* set_sort_func)         (GtkTreeSortable        *sortable,
				      gint                    sort_column_id,
				      GtkTreeIterCompareFunc  sort_func,
				      gpointer                user_data,
				      GDestroyNotify          destroy);
  void     (* set_default_sort_func) (GtkTreeSortable        *sortable,
				      GtkTreeIterCompareFunc  sort_func,
				      gpointer                user_data,
				      GDestroyNotify          destroy);
  gboolean (* has_default_sort_func) (GtkTreeSortable        *sortable);
};


GType    gtk_tree_sortable_get_type              (void) G_GNUC_CONST;

void     gtk_tree_sortable_sort_column_changed   (GtkTreeSortable        *sortable);
gboolean gtk_tree_sortable_get_sort_column_id    (GtkTreeSortable        *sortable,
						  gint                   *sort_column_id,
						  GtkSortType            *order);
void     gtk_tree_sortable_set_sort_column_id    (GtkTreeSortable        *sortable,
						  gint                    sort_column_id,
						  GtkSortType             order);
void     gtk_tree_sortable_set_sort_func         (GtkTreeSortable        *sortable,
						  gint                    sort_column_id,
						  GtkTreeIterCompareFunc  sort_func,
						  gpointer                user_data,
						  GDestroyNotify          destroy);
void     gtk_tree_sortable_set_default_sort_func (GtkTreeSortable        *sortable,
						  GtkTreeIterCompareFunc  sort_func,
						  gpointer                user_data,
						  GDestroyNotify          destroy);
gboolean gtk_tree_sortable_has_default_sort_func (GtkTreeSortable        *sortable);

G_END_DECLS

#endif /* __GTK_TREE_SORTABLE_H__ */