<?php
/*********************************************************************************
 * SugarCRM Community Edition is a customer relationship management program developed by
 * SugarCRM, Inc. Copyright (C) 2004-2011 SugarCRM Inc.
 * 
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Affero General Public License version 3 as published by the
 * Free Software Foundation with the addition of the following permission added
 * to Section 15 as permitted in Section 7(a): FOR ANY PART OF THE COVERED WORK
 * IN WHICH THE COPYRIGHT IS OWNED BY SUGARCRM, SUGARCRM DISCLAIMS THE WARRANTY
 * OF NON INFRINGEMENT OF THIRD PARTY RIGHTS.
 * 
 * This program 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 Affero General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU Affero General Public License along with
 * this program; if not, see http://www.gnu.org/licenses or write to the Free
 * Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301 USA.
 * 
 * You can contact SugarCRM, Inc. headquarters at 10050 North Wolfe Road,
 * SW2-130, Cupertino, CA 95014, USA. or at email address contact@sugarcrm.com.
 * 
 * The interactive user interfaces in modified source and object code versions
 * of this program must display Appropriate Legal Notices, as required under
 * Section 5 of the GNU Affero General Public License version 3.
 * 
 * In accordance with Section 7(b) of the GNU Affero General Public License version 3,
 * these Appropriate Legal Notices must retain the display of the "Powered by
 * SugarCRM" logo. If the display of the logo is not reasonably feasible for
 * technical reasons, the Appropriate Legal Notices must display the words
 * "Powered by SugarCRM".
 ********************************************************************************/


require_once('include/SugarCache/SugarCacheAbstract.php');

class SugarCacheFile extends SugarCacheAbstract
{
    /**
     * @var path and file which will store the cache used for this backend
     */
    protected $_cacheFileName = 'externalCache.php';
    
    /**
     * @var bool true if the cache has changed and needs written to disk
     */
    protected $_cacheChanged = false;
    
    /**
     * @see SugarCacheAbstract::$_priority
     */
    protected $_priority = 990;
    
    /**
     * @see SugarCacheAbstract::useBackend()
     */
    public function useBackend()
    {
        if ( !parent::useBackend() )
            return false;
        
        if ( !empty($GLOBALS['sugar_config']['external_cache_enabled_file']) )
            return true;
            
        return false;
    }
    
    /**
     * @see SugarCacheAbstract::__construct()
     *
     * For this backend, we'll read from the SugarCacheFile::_cacheFileName file into 
     * the SugarCacheFile::$localCache array.
     */
    public function __construct()
    {
        parent::__construct();
        
        if ( isset($GLOBALS['sugar_config']['external_cache_filename']) )
            $this->_cacheFileName = $GLOBALS['sugar_config']['external_cache_filename'];
    }
    
    /**
     * @see SugarCacheAbstract::__destruct()
     *
     * For this backend, we'll write the SugarCacheFile::$localCache array serialized out to a file
     */
    public function __destruct()
    {
        parent::__destruct();
        
        if ( $this->_cacheChanged )
            sugar_file_put_contents($GLOBALS['sugar_config']['cache_dir'].'/'.$this->_cacheFileName,
                serialize($this->_localStore));
    }
    
    /**
     * @see SugarCacheAbstract::_setExternal()
     *
     * Does nothing; we write to cache on destroy
     */
    protected function _setExternal(
        $key,
        $value
        )
    {
        $this->_cacheChanged = true;
    }
    
    /**
     * @see SugarCacheAbstract::_getExternal()
     */
    protected function _getExternal(
        $key
        )
    {
        // load up the external cache file
        if ( sugar_is_file($GLOBALS['sugar_config']['cache_dir'].'/'.$this->_cacheFileName) )
            $this->localCache = unserialize(
                file_get_contents($GLOBALS['sugar_config']['cache_dir'].'/'.$this->_cacheFileName));
        
        if ( isset($this->_localStore[$key]) )
            return $this->_localStore[$key];
    }
    
    /**
     * @see SugarCacheAbstract::_clearExternal()
     *
     * Does nothing; we write to cache on destroy
     */
    protected function _clearExternal(
        $key
        )
    {
        $this->_cacheChanged = true;
    }
    
    /**
     * @see SugarCacheAbstract::_resetExternal()
     *
     * Does nothing; we write to cache on destroy
     */
    protected function _resetExternal()
    {
        $this->_cacheChanged = true;
    }
}
