[李景山php]thinkphp核心源码注释|Sqlite.class.php

<?php// +----------------------------------------------------------------------// | ThinkPHP [ WE CAN DO IT JUST THINK ]// +----------------------------------------------------------------------// | Copyright (c) 2006-2014 http://thinkphp.cn All rights reserved.// +----------------------------------------------------------------------// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )// +----------------------------------------------------------------------// | Author: liu21st <[e-mail]>// +----------------------------------------------------------------------namespace Think\Cache\Driver;use Think\Cache;defined('THINK_PATH') or exit();/** * Sqlite缓存驱动 * 很小的一个数据库文件，不过不错，估计没什么大的创新 */class Sqlite extends Cache {    /**     * 架构函数     * @param array $options 缓存参数     * @access public     * 架构 构造函数     */    public function __construct($options=array()) {        if ( !extension_loaded('sqlite') ) {            E(L('_NOT_SUPPORT_').':sqlite');        }        if(empty($options)) {            $options = array (                'db'        =>  ':memory:',                'table'     =>  'sharedmemory',            );        }        $this->options  =   $options;              $this->options['prefix']    =   isset($options['prefix'])?  $options['prefix']  :   C('DATA_CACHE_PREFIX');        $this->options['length']    =   isset($options['length'])?  $options['length']  :   0;                $this->options['expire']    =   isset($options['expire'])?  $options['expire']  :   C('DATA_CACHE_TIME');        $func = $this->options['persistent'] ? 'sqlite_popen' : 'sqlite_open';        $this->handler      = $func($this->options['db']);    }    /**     * 读取缓存     * @access public     * @param string $name 缓存变量名     * @return mixed     *     */    public function get($name) {        N('cache_read',1);// 记录        $name   = $this->options['prefix'].sqlite_escape_string($name);        $sql    = 'SELECT value FROM '.$this->options['table'].' WHERE var=\''.$name.'\' AND (expire=0 OR expire >'.time().') LIMIT 1';        $result = sqlite_query($this->handler, $sql);// 看来你也是 sql 之中的一员啊        if (sqlite_num_rows($result)) {            $content   =  sqlite_fetch_single($result);// 系统函数            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     * @param integer $expire  有效时间（秒）     * @return boolean     */    public function set($name, $value,$expire=null) {        N('cache_write',1);        $name  = $this->options['prefix'].sqlite_escape_string($name);        $value = sqlite_escape_string(serialize($value));        if(is_null($expire)) {            $expire  =  $this->options['expire'];        }        $expire=($expire==0)?0: (time()+$expire) ;//缓存有效期为0表示永久缓存        if( C('DATA_CACHE_COMPRESS') && function_exists('gzcompress')) {            //数据压缩            $value   =   gzcompress($value,3);            // var_dump( gzuncompress(gzcompress('lijingshan')) );        }        $sql  = 'REPLACE INTO '.$this->options['table'].' (var, value,expire) VALUES (\''.$name.'\', \''.$value.'\', \''.$expire.'\')';        if(sqlite_query($this->handler, $sql)){            if($this->options['length']>0) {                // 记录缓存队列                $this->queue($name);// 队列记录            }            return true;        }        return false;    }    /**     * 删除缓存     * @access public     * @param string $name 缓存变量名     * @return boolean     * 同样需要数据表的一个支持呢     */    public function rm($name) {        $name  = $this->options['prefix'].sqlite_escape_string($name);        $sql  = 'DELETE FROM '.$this->options['table'].' WHERE var=\''.$name.'\'';        sqlite_query($this->handler, $sql);        return true;    }    /**     * 清除缓存     * @access public     * @return boolean     * 为什么不直接清空数据表呢     */    public function clear() {        $sql  = 'DELETE FROM '.$this->options['table'];        sqlite_query($this->handler, $sql);        return ;    }}// 总结，没什么特殊的了，