question: void addUndoAction ( UndoAction action ) { int iAction = m_undoStack . size ( ) - 1 ; while ( iAction > m_nCurrentEditAction ) { m_undoStack . remove ( iAction -- ) ; } if ( m_nSavedPointer > m_nCurrentEditAction ) { m_nSavedPointer = - 2 ; } m_undoStack . add ( action ) ; m_nCurrentEditAction ++ ; }
target:  add undo action to the undo stack.