<?php

/**
 * PHPExcel_CachedObjectStorage_Memory
 *
 * 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##
 */
class PHPExcel_CachedObjectStorage_Memory extends PHPExcel_CachedObjectStorage_CacheBase implements PHPExcel_CachedObjectStorage_ICache
{

    /**
     * Dummy method callable from CacheBase, but unused by Memory cache
     *
     * @return void
     */
    protected function storeData()
    {}

    /**
     * Add or Update a cell in cache identified by coordinate address
     *
     * @param string $pCoord
     *            Coordinate address of the cell to update
     * @param PHPExcel_Cell $cell
     *            Cell to update
     * @return PHPExcel_Cell
     * @throws PHPExcel_Exception
     */
    public function addCacheData($pCoord, PHPExcel_Cell $cell)
    {
        $this->cellCache[$pCoord] = $cell;
        
        // Set current entry to the new/updated entry
        $this->currentObjectID = $pCoord;
        
        return $cell;
    }

    /**
     * Get cell at a specific coordinate
     *
     * @param string $pCoord
     *            Coordinate of the cell
     * @throws PHPExcel_Exception
     * @return PHPExcel_Cell Cell that was found, or null if not found
     */
    public function getCacheData($pCoord)
    {
        // Check if the entry that has been requested actually exists
        if (! isset($this->cellCache[$pCoord])) {
            $this->currentObjectID = null;
            // Return null if requested entry doesn't exist in cache
            return null;
        }
        
        // Set current entry to the requested entry
        $this->currentObjectID = $pCoord;
        
        // Return requested entry
        return $this->cellCache[$pCoord];
    }

    /**
     * Clone the cell collection
     *
     * @param PHPExcel_Worksheet $parent
     *            The new worksheet
     */
    public function copyCellCollection(PHPExcel_Worksheet $parent)
    {
        parent::copyCellCollection($parent);
        
        $newCollection = array();
        foreach ($this->cellCache as $k => &$cell) {
            $newCollection[$k] = clone $cell;
            $newCollection[$k]->attach($this);
        }
        
        $this->cellCache = $newCollection;
    }

    /**
     * Clear the cell collection and disconnect from our parent
     */
    public function unsetWorksheetCells()
    {
        // Because cells are all stored as intact objects in memory, we need to detach each one from the parent
        foreach ($this->cellCache as $k => &$cell) {
            $cell->detach();
            $this->cellCache[$k] = null;
        }
        unset($cell);
        
        $this->cellCache = array();
        
        // detach ourself from the worksheet, so that it can then delete this object successfully
        $this->parent = null;
    }
}
