<?php

// +----------------------------------------------------------------------

// | ThinkPHP [ WE CAN DO IT JUST THINK IT ]

// +----------------------------------------------------------------------

// | Copyright (c) 2009 http://thinkphp.cn All rights reserved.

// +----------------------------------------------------------------------

// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )

// +----------------------------------------------------------------------

// | Author: liu21st <liu21st@gmail.com>

// +----------------------------------------------------------------------

// $Id$



/**

 +------------------------------------------------------------------------------

 * Sqlite缓存类

 +------------------------------------------------------------------------------

 * @category   Think

 * @package  Think

 * @subpackage  Util

 * @author    liu21st <liu21st@gmail.com>

 * @version   $Id$

 +------------------------------------------------------------------------------

 */

class CacheSqlite extends Cache

{



    /**

     +----------------------------------------------------------

     * 架构函数

     +----------------------------------------------------------

     * @access public

     +----------------------------------------------------------

     */

    public function __construct($options='')

    {

        if ( !extension_loaded('sqlite') ) {

            throw_exception(L('_NOT_SUPPERT_').':sqlite');

        }

        if(empty($options)){

            $options= array

            (

                'db'        => ':memory:',

                'table'     => 'sharedmemory',

                'var'       => 'var',

                'value'     => 'value',

                'expire'    => 'expire',

                'persistent'=> false

            );

        }

        $this->options = $options;

        $func = $this->options['persistent'] ? 'sqlite_popen' : 'sqlite_open';

        $this->handler = $func($this->options['db']);

        $this->connected = is_resource($this->handler);

        $this->type = strtoupper(substr(__CLASS__,6));



    }



    /**

     +----------------------------------------------------------

     * 是否连接

     +----------------------------------------------------------

     * @access private

     +----------------------------------------------------------

     * @return boolen

     +----------------------------------------------------------

     */

    private function isConnected()

    {

        return $this->connected;

    }



    /**

     +----------------------------------------------------------

     * 读取缓存

     +----------------------------------------------------------

     * @access public

     +----------------------------------------------------------

     * @param string $name 缓存变量名

     +----------------------------------------------------------

     * @return mixed

     +----------------------------------------------------------

     */

    public function get($name)

    {

        N('cache_read',1);

		$name   = sqlite_escape_string($name);

        $sql = 'SELECT '.$this->options['value'].

               ' FROM '.$this->options['table'].

               ' WHERE '.$this->options['var'].'=\''.$name.'\' AND ('.$this->options['expire'].'=-1 OR '.$this->options['expire'].'>'.time().

               ') LIMIT 1';

        $result = sqlite_query($this->handler, $sql);

        if (sqlite_num_rows($result)) {

            $content   =  sqlite_fetch_single($result);

            if(C('DATA_CACHE_COMPRESS') && function_exists('gzcompress')) {

                //启用数据压缩

                $content   =   gzuncompress($content);

            }

            return unserialize($content);

        }

        return false;

    }



    /**

     +----------------------------------------------------------

     * 写入缓存

     +----------------------------------------------------------

     * @access public

     +----------------------------------------------------------

     * @param string $name 缓存变量名

     * @param mixed $value  存储数据

     +----------------------------------------------------------

     * @return boolen

     +----------------------------------------------------------

     */

    public function set($name, $value,$expireTime=0)

    {

        N('cache_write',1);

        $expire =  !empty($expireTime)? $expireTime : C('DATA_CACHE_TIME');

        $name  = sqlite_escape_string($name);

        $value = sqlite_escape_string(serialize($value));

        $expire =  ($expireTime==-1)?-1: (time()+$expire);

        if( C('DATA_CACHE_COMPRESS') && function_exists('gzcompress')) {

            //数据压缩

            $value   =   gzcompress($value,3);

        }

        $sql  = 'REPLACE INTO '.$this->options['table'].

                ' ('.$this->options['var'].', '.$this->options['value'].','.$this->options['expire'].

                ') VALUES (\''.$name.'\', \''.$value.'\', \''.$expire.'\')';

        sqlite_query($this->handler, $sql);

        return true;

    }



    /**

     +----------------------------------------------------------

     * 删除缓存

     +----------------------------------------------------------

     * @access public

     +----------------------------------------------------------

     * @param string $name 缓存变量名

     +----------------------------------------------------------

     * @return boolen

     +----------------------------------------------------------

     */

    public function rm($name)

    {

        $name  = sqlite_escape_string($name);

        $sql  = 'DELETE FROM '.$this->options['table'].

               ' WHERE '.$this->options['var'].'=\''.$name.'\'';

        sqlite_query($this->handler, $sql);

        return true;

    }



    /**

     +----------------------------------------------------------

     * 清除缓存

     +----------------------------------------------------------

     * @access public

     +----------------------------------------------------------

     * @return boolen

     +----------------------------------------------------------

     */

    public function clear()

    {

        $sql  = 'delete from `'.$this->options['table'].'`';

        sqlite_query($this->handler, $sql);

        return ;

    }

}//类定义结束

?>