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/**
* @file llundo.h
* @brief Generic interface for undo/redo circular buffer.
*
* $LicenseInfo:firstyear=2000&license=viewergpl$
*
* Copyright (c) 2000-2007, Linden Research, Inc.
*
* Second Life Viewer Source Code
* The source code in this file ("Source Code") is provided by Linden Lab
* to you under the terms of the GNU General Public License, version 2.0
* ("GPL"), unless you have obtained a separate licensing agreement
* ("Other License"), formally executed by you and Linden Lab. Terms of
* the GPL can be found in doc/GPL-license.txt in this distribution, or
* online at http://secondlife.com/developers/opensource/gplv2
*
* There are special exceptions to the terms and conditions of the GPL as
* it is applied to this Source Code. View the full text of the exception
* in the file doc/FLOSS-exception.txt in this software distribution, or
* online at http://secondlife.com/developers/opensource/flossexception
*
* By copying, modifying or distributing this software, you acknowledge
* that you have read and understood your obligations described above,
* and agree to abide by those obligations.
*
* ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
* WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
* COMPLETENESS OR PERFORMANCE.
* $/LicenseInfo$
*/
#ifndef LL_LLUNDO_H
#define LL_LLUNDO_H
class LLUndoBuffer
{
public:
class LLUndoAction
{
friend class LLUndoBuffer;
public:
virtual void undo() = 0;
virtual void redo() = 0;
virtual void cleanup() {};
protected:
LLUndoAction(): mClusterID(0) {};
virtual ~LLUndoAction(){};
private:
S32 mClusterID;
};
LLUndoBuffer( LLUndoAction (*create_func()), S32 initial_count );
virtual ~LLUndoBuffer();
LLUndoAction *getNextAction(BOOL setClusterBegin = TRUE);
BOOL undoAction();
BOOL redoAction();
BOOL canUndo() { return (mNextAction != mFirstAction); }
BOOL canRedo() { return (mNextAction != mLastAction); }
void flushActions();
private:
LLUndoAction **mActions; // array of pointers to undoactions
S32 mNumActions; // total number of actions in ring buffer
S32 mNextAction; // next action to perform undo/redo on
S32 mLastAction; // last action actually added to undo buffer
S32 mFirstAction; // beginning of ring buffer (don't undo any further)
S32 mOperationID; // current operation id, for undoing and redoing in clusters
};
#endif //LL_LLUNDO_H
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