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/**
* @file llundo.h
* @brief Generic interface for undo/redo circular buffer.
*
* $LicenseInfo:firstyear=2000&license=viewerlgpl$
* Second Life Viewer Source Code
* Copyright (C) 2010, Linden Research, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License only.
*
* 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
* $/LicenseInfo$
*/
#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() const { return (mNextAction != mFirstAction); }
bool canRedo() const { 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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