当前路径：Classes/PHPExcel/CachedObjectStorage/CacheBase.php
<?php

/**
 * PHPExcel_CachedObjectStorage_CacheBase
 *
 * Copyright (c) 2006 - 2015 PHPExcel
 *
 * 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; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * 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
 *
 * @category   PHPExcel
 * @package    PHPExcel_CachedObjectStorage
 * @copyright  Copyright (c) 2006 - 2015 PHPExcel (http://www.codeplex.com/PHPExcel)
 * @license    http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt    LGPL
 * @version    ##VERSION##, ##DATE##
 */
abstract class PHPExcel_CachedObjectStorage_CacheBase
{
    /**
     * Parent worksheet
     *
     * @var PHPExcel_Worksheet
     */
    protected $parent;

    /**
     * The currently active Cell
     *
     * @var PHPExcel_Cell
     */
    protected $currentObject = null;

    /**
     * Coordinate address of the currently active Cell
     *
     * @var string
     */
    protected $currentObjectID = null;

    /**
     * Flag indicating whether the currently active Cell requires saving
     *
     * @var boolean
     */
    protected $currentCellIsDirty = true;

    /**
     * An array of cells or cell pointers for the worksheet cells held in this cache,
     *        and indexed by their coordinate address within the worksheet
     *
     * @var array of mixed
     */
    protected $cellCache = array();

    /**
     * Initialise this new cell collection
     *
     * @param    PHPExcel_Worksheet    $parent        The worksheet for this cell collection
     */
    public function __con...