qofundo-p.h

/***************************************************************************
 *            qofundo-p.h
 *
 *  Thu Aug 25 09:20:14 2005
 *  Copyright  2005,2006  Neil Williams
 *  linux@codehelp.co.uk
 ****************************************************************************/
/*
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor Boston, MA  02110-1301,  USA
 */

#ifndef _QOFUNDO_P_H
#define _QOFUNDO_P_H

#include <qof.h>
#include "qofundo.h"

typedef struct QofUndoEntity_t QofUndoEntity;

typedef struct QofUndoOperation_t QofUndoOperation;

typedef struct QofUndo_s
{
    GList *undo_list;
    GList *undo_cache;
    gchar *undo_label;
    gint index_position;
    gboolean undo_operation_open;
} QofUndo;

/* Undo is limited, not infinite. */
#define MAX_UNDO_LENGTH     300

/* reads the data from this parameter to allow undo

To be able to undo and then redo an action, QOF needs to know the
before and after states. Initially, the before state is the same as
the file but after that point, the state of the entity needs to be
tracked whenever it is opened for editing.
*/
QofUndoEntity *
qof_prepare_undo (QofEntity * ent, const QofParam * param);

/* Add the changes to be undone to the event.

Designed to be used with g_list_foreach, simply adds
any number of undo_entity pointers (representing the 
entity changes relating to this event) to the list 
of changes for this event.
*/
void 
qof_undo_new_entry (gpointer event, gpointer changes);

/* Add an undo event to the list.

type holds the type of event that has just occurred.

If the event follows a successful qof_commit_edit, then the
cached undo_entity changes are placed into this undo_event.
*/
QofUndoOperation *
qof_undo_new_operation (QofBook * book, gchar * label);

#endif /* _QOFUNDO_P_H */

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