<?php

/**
 * PHPExcel_CachedObjectStorage_Wincache
 *
 * 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_Wincache extends PHPExcel_CachedObjectStorage_CacheBase implements PHPExcel_CachedObjectStorage_ICache
{
  /**
   * Prefix used to uniquely identify cache data for this worksheet
   *
   * @var string
   */
  private $cachePrefix = null;
  
  /**
   * Cache timeout
   *
   * @var integer
   */
  private $cacheTime = 600;
  
  /**
   * Store cell data in cache for the current cell object if it's "dirty",
   * and the 'nullify' the current cell object
   *
   * @return void
   * @throws PHPExcel_Exception
   */
  protected function storeData()
  {
    if ($this->currentCellIsDirty && ! empty ( $this->currentObjectID ))
    {
      $this->currentObject->detach ();
      
      $obj = serialize ( $this->currentObject );
      if (wincache_ucache_exists ( $this->cachePrefix . $this->currentObjectID . '.cache' ))
      {
        if (! wincache_ucache_set ( $this->cachePrefix . $this->currentObjectID . '.cache', $obj, $this->cacheTime ))
        {
          $this->__destruct ();
          throw new PHPExcel_Exception ( 'Failed to store cell ' . $this->currentObjectID . ' in WinCache' );
        }
      }
      else
      {
        if (! wincache_ucache_add ( $this->cachePrefix . $this->currentObjectID . '.cache', $obj, $this->cacheTime ))
        {
          $this->__destruct ();
          throw new PHPExcel_Exception ( 'Failed to store cell ' . $this->currentObjectID . ' in WinCache' );
        }
      }
      $this->currentCellIsDirty = false;
    }
    
    $this->currentObjectID = $this->currentObject = null;
  }
  
  /**
   * 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 $cell)
  {
    if (($pCoord !== $this->currentObjectID) && ($this->currentObjectID !== null))
    {
      $this->storeData ();
    }
    $this->cellCache [$pCoord] = true;
    
    $this->currentObjectID = $pCoord;
    $this->currentObject = $cell;
    $this->currentCellIsDirty = true;
    
    return $cell;
  }
  
  /**
   * Is a value set in the current PHPExcel_CachedObjectStorage_ICache for an indexed cell?
   *
   * @param string $pCoord
   *          Coordinate address of the cell to check
   * @return boolean
   */
  public function isDataSet($pCoord)
  {
    // Check if the requested entry is the current object, or exists in the cache
    if (parent::isDataSet ( $pCoord ))
    {
      if ($this->currentObjectID == $pCoord)
      {
        return true;
      }
      // Check if the requested entry still exists in cache
      $success = wincache_ucache_exists ( $this->cachePrefix . $pCoord . '.cache' );
      if ($success === false)
      {
        // Entry no longer exists in Wincache, so clear it from the cache array
        parent::deleteCacheData ( $pCoord );
        throw new PHPExcel_Exception ( 'Cell entry ' . $pCoord . ' no longer exists in WinCache' );
      }
      return true;
    }
    return false;
  }
  
  /**
   * 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)
  {
    if ($pCoord === $this->currentObjectID)
    {
      return $this->currentObject;
    }
    $this->storeData ();
    
    // Check if the entry that has been requested actually exists
    $obj = null;
    if (parent::isDataSet ( $pCoord ))
    {
      $success = false;
      $obj = wincache_ucache_get ( $this->cachePrefix . $pCoord . '.cache', $success );
      if ($success === false)
      {
        // Entry no longer exists in WinCache, so clear it from the cache array
        parent::deleteCacheData ( $pCoord );
        throw new PHPExcel_Exception ( 'Cell entry ' . $pCoord . ' no longer exists in WinCache' );
      }
    }
    else
    {
      // Return null if requested entry doesn't exist in cache
      return null;
    }
    
    // Set current entry to the requested entry
    $this->currentObjectID = $pCoord;
    $this->currentObject = unserialize ( $obj );
    // Re-attach this as the cell's parent
    $this->currentObject->attach ( $this );
    
    // Return requested entry
    return $this->currentObject;
  }
  
  /**
   * Get a list of all cell addresses currently held in cache
   *
   * @return string[]
   */
  public function getCellList()
  {
    if ($this->currentObjectID !== null)
    {
      $this->storeData ();
    }
    
    return parent::getCellList ();
  }
  
  /**
   * Delete a cell in cache identified by coordinate address
   *
   * @param string $pCoord
   *          Coordinate address of the cell to delete
   * @throws PHPExcel_Exception
   */
  public function deleteCacheData($pCoord)
  {
    // Delete the entry from Wincache
    wincache_ucache_delete ( $this->cachePrefix . $pCoord . '.cache' );
    
    // Delete the entry from our cell address array
    parent::deleteCacheData ( $pCoord );
  }
  
  /**
   * Clone the cell collection
   *
   * @param PHPExcel_Worksheet $parent
   *          The new worksheet
   * @return void
   */
  public function copyCellCollection(PHPExcel_Worksheet $parent)
  {
    parent::copyCellCollection ( $parent );
    // Get a new id for the new file name
    $baseUnique = $this->getUniqueID ();
    $newCachePrefix = substr ( md5 ( $baseUnique ), 0, 8 ) . '.';
    $cacheList = $this->getCellList ();
    foreach ( $cacheList as $cellID )
    {
      if ($cellID != $this->currentObjectID)
      {
        $success = false;
        $obj = wincache_ucache_get ( $this->cachePrefix . $cellID . '.cache', $success );
        if ($success === false)
        {
          // Entry no longer exists in WinCache, so clear it from the cache array
          parent::deleteCacheData ( $cellID );
          throw new PHPExcel_Exception ( 'Cell entry ' . $cellID . ' no longer exists in Wincache' );
        }
        if (! wincache_ucache_add ( $newCachePrefix . $cellID . '.cache', $obj, $this->cacheTime ))
        {
          $this->__destruct ();
          throw new PHPExcel_Exception ( 'Failed to store cell ' . $cellID . ' in Wincache' );
        }
      }
    }
    $this->cachePrefix = $newCachePrefix;
  }
  
  /**
   * Clear the cell collection and disconnect from our parent
   *
   * @return void
   */
  public function unsetWorksheetCells()
  {
    if (! is_null ( $this->currentObject ))
    {
      $this->currentObject->detach ();
      $this->currentObject = $this->currentObjectID = null;
    }
    
    // Flush the WinCache cache
    $this->__destruct ();
    
    $this->cellCache = array ();
    
    // detach ourself from the worksheet, so that it can then delete this object successfully
    $this->parent = null;
  }
  
  /**
   * Initialise this new cell collection
   *
   * @param PHPExcel_Worksheet $parent
   *          The worksheet for this cell collection
   * @param
   *          array of mixed $arguments Additional initialisation arguments
   */
  public function __construct(PHPExcel_Worksheet $parent, $arguments)
  {
    $cacheTime = (isset ( $arguments ['cacheTime'] )) ? $arguments ['cacheTime'] : 600;
    
    if (is_null ( $this->cachePrefix ))
    {
      $baseUnique = $this->getUniqueID ();
      $this->cachePrefix = substr ( md5 ( $baseUnique ), 0, 8 ) . '.';
      $this->cacheTime = $cacheTime;
      
      parent::__construct ( $parent );
    }
  }
  
  /**
   * Destroy this cell collection
   */
  public function __destruct()
  {
    $cacheList = $this->getCellList ();
    foreach ( $cacheList as $cellID )
    {
      wincache_ucache_delete ( $this->cachePrefix . $cellID . '.cache' );
    }
  }
  
  /**
   * Identify whether the caching method is currently available
   * Some methods are dependent on the availability of certain extensions being enabled in the PHP build
   *
   * @return boolean
   */
  public static function cacheMethodIsAvailable()
  {
    if (! function_exists ( 'wincache_ucache_add' ))
    {
      return false;
    }
    
    return true;
  }
}
