/*
* Authors:
* David Yip <yipdw@rose-hulman.edu>
*
* Copyright (c) 2005 Authors
*
* Released under GNU GPL, read the file 'COPYING' for more information
*/
#ifndef SEEN_UNDO_COMMIT_OBSERVER_H
#define SEEN_UNDO_COMMIT_OBSERVER_H
#include "inkgc/gc-managed.h"
namespace Inkscape {
struct Event;
/**
* Observes changes made to the undo and redo stacks.
*
* More specifically, an UndoStackObserver is a class that receives notifications when
* any of the following events occur:
* <ul>
* <li>A change is committed to the undo stack.</li>
* <li>An undo action is made.</li>
* <li>A redo action is made.</li>
* </ul>
*
* UndoStackObservers should not be used on their own. Instead, they should be registered
* with a CompositeUndoStackObserver.
*/
class UndoStackObserver : public GC::Managed<> {
public:
UndoStackObserver() { }
virtual ~UndoStackObserver() { }
/**
* Triggered when the user issues an undo command.
*
* \param log Pointer to an Event describing the undone event.
*/
virtual void notifyUndoEvent(Event* log) = 0;
/**
* Triggered when the user issues a redo command.
*
* \param log Pointer to an Event describing the redone event.
*/
virtual void notifyRedoEvent(Event* log) = 0;
/**
* Triggered when a set of transactions is committed to the undo log.
*
* \param log Pointer to an Event describing the committed events.
*/
virtual void notifyUndoCommitEvent(Event* log) = 0;
/**
* Triggered when the undo log is cleared.
*/
virtual void notifyClearUndoEvent() = 0;
/**
* Triggered when the redo log is cleared.
*/
virtual void notifyClearRedoEvent() = 0;
};
}
#endif // SEEN_UNDO_COMMIT_OBSERVER_H