php discuz 核心类函数分析

<?php

/**
 *      [Discuz!] (C)2001-2099 Comsenz Inc.
 *      This is NOT a freeware, use is subject to license terms
 *
 *      $Id: class_core.php 6914 2010-03-26 12:52:36Z cnteacher $
 */

///TODO 是将要完成的功能，包括禁止ip和禁止访问
//TODO 禁止ip
//TODO 禁止访问

///和DZ72一样，确保所有文件需要先加载核心文件
define('IN_DISCUZ', true);

/**
 * Discuz 核心引擎
 * 其他处理代码当中用到的变量不要在本核心 new 之前设置， 否则会自动清空
 *
 */
class discuz_core {

    // 数据库存储引擎
    var $db = null;

    // 内存缓冲object
    var $mem = null;

    // 会话 object
    var $session = null;

    // 程序配置
    var $config = array();

    // $_G 数组的映射
    var $var = array();

    // 加载缓存的数组
    var $cachelist = array();

    // 是否初始化
    var $init_setting = true; //设置
    var $init_user = true;//用户
    var $init_session = true;//会话
    var $init_cron = true;//任务计划
    var $init_misc = true;//其他功能
    var $init_memory = true;//内存

    // 是否已经初始化
    var $initated = false;

    var $superglobal = array(
        'GLOBALS' => 1,
        '_GET' = 1,
        '_POST' = 1,
        '_REQUEST' = 1,
        '_COOKIE' = 1,
        '_SERVER' = 1,
        '_ENV' = 1,
        '_FILES' = 1,
    );

    function &instance() {
        static $object;
        if(empty($object)) {
            $object = new discuz_core();
        }
        return $object;
    }

    function discuz_core() {
        $this->_init_env();
        $this->_init_config();
        $this->_init_input();
        $this->_init_output();
    }

    function init() {
        if(!$this->initated) {
            $this->_init_db();
            $this->_init_memory();
            $this->_init_user();
            $this->_init_session();
            $this->_init_setting();
            $this->_init_cron();
            $this->_init_misc();
        }
        $this->initated = true;
    }

    function _init_env() {

        error_reporting(E_ALL ^ E_NOTICE);
//        error_reporting(E_ALL);
        ///php 5.3前则关闭魔法引号匹配(自动转义)
        if(phpversion() < '5.3.0') {
            set_magic_quotes_runtime(0);
        }

        ///程序主目录，根据核心文件确定，原来是-7 代表在include下,现在是12代表在source/class下
        define('DISCUZ_ROOT', substr(dirname(__FILE__), 0, -12));
        ///和dz72一样，设置魔法引用(自动转义，单双引号反斜线)
        define('MAGIC_QUOTES_GPC', function_exists('get_magic_quotes_gpc') && get_magic_quotes_gpc());
        ///判断字符编码转换函数是否存在
        define('ICONV_ENABLE', function_exists('iconv'));
        ///亚洲字符转码函数是否存在, 因为mb_开头字符处理亚洲字符会比较高效，初步判断用于转码时先用mb_来处理:
        define('MB_ENABLE', function_exists('mb_convert_encoding'));
        ///是否存在输出缓存压缩函数，这个函数的目的，是在确认浏览器支持页面压缩后，才用该函数来压缩所有输出内容，否则直接传输
        define('EXT_OBGZIP', function_exists('ob_gzhandler'));

        ///和DZ72一样，不过当前时间戳被定义为一个常量，效率更高吧，也不用global了。
        define('TIMESTAMP', time());
        ///获取默认时区
        discuz_core::timezone_set();

        ///加载function_core.php，作用推测类似global.func.php
        if(!defined('DISCUZ_CORE_FUNCTION') && !@include(DISCUZ_ROOT.'./source/function/function_core.php')) {
            $this->error('function_core.php is missing');
        }

        //判断浏览器是否是蜘蛛
        define('IS_ROBOT', checkrobot());

        //清理全局变量
        ///全清理了，真是彻底把所有变量都从内存中注销了
        foreach ($GLOBALS as $key = $value) {
            if (!isset($this->superglobal[$key])) {
                $GLOBALS[$key] = null; unset($GLOBALS[$key]);
            }
        }

        // 配置全局变量
        ///和上一步结合，只留下自己需要的变量，并初始化。
        ///这么做够狠，只要稍微小心点，就不会出现因为变量未初始化而出现的安全问题
        global $_G;
        $_G = array(
            //公用全局定义
            'uid' = 0,
            'username' = '',
            'adminid' = 0,
            'groupid' = 1,
            'sid' = '',
            'formhash' = '',
            'timestamp' = TIMESTAMP,
            'starttime' = dmicrotime(),
            'clientip' = $this->_get_client_ip(),
            'referer' = '',
            'charset' = '',
            'gzipcompress' = '',
            'authkey' = '',
            'timenow' = array(),

            'PHP_SELF' = '',
            'siteurl' = '',

            //公用全局数组定义
            'config' = array(),
            'setting' = array(),
            'member' = array(),
            'group' = array(),
            'cookie' = array(),
            'style' = array(),
            'cache' = array(),
            'session' = array(),
            'lang' = array(),
            'my_app' = array(),//默认应用
            'my_userapp' = array(),//用户自添加应用

            //论坛全局定义
            'fid' = 0,
            'tid' = 0,
            'forum' = array(),
            'rssauth' = '',

            //uch 全局定义
            'home' = array(),
            'space' = array(),

            //portal 全局定义
            'block' = array(),
            'article' = array(),

            //Action
            'action' = array(
                'action' = APPTYPEID,
                'fid' = 0,
                'tid' = 0,
            )
        );
        //相对主目录的相对地址及文件名
        $_G['PHP_SELF'] = htmlspecialchars($_SERVER['PHP_SELF'] ? $_SERVER['PHP_SELF'] : $_SERVER['SCRIPT_NAME']);
        //基本脚本名，每个功能脚本首页前都会定义
        //比如forum.php，则定义CURSCRIPT为forum,而forum_forumdisplay.php则不定义，因为属于forum
        $_G['basescript'] = CURSCRIPT;
        //站点网址
        $_G['siteurl'] = htmlspecialchars('http://'.$_SERVER['HTTP_HOST'].preg_replace("/\/+(api)?\/*$/i", '', substr($_G['PHP_SELF'], 0, strrpos($_G['PHP_SELF'], '/'))).'/');

        ///$_G的映射，也即超级全局变量
        $this->var = & $_G;

    }

    function _init_input() {

        //note 禁止对全局变量注入
        ///和dz72类似，禁止GLOBALS=xxx的方式注入
        if (isset($_REQUEST['GLOBALS']) || isset($_FILES['GLOBALS'])) {
            error('request_tainting');
        }

        if(!empty($_GET['rewrite'])) {
            $query_string = '?mod=';
            $param = explode('-', $_GET['rewrite']);
            $query_string .= $_GET['mod'] = $param[0];
            array_shift($param);
            $paramc = count($param);
            for($i = 0;$i < $paramc;$i+=2) {
                $_REQUEST[$param[$i]] = $_GET[$param[$i]] = $param[$i + 1];
                $query_string .= '&'.$param[$i].'='.$param[$i + 1];
            }
            $_SERVER['QUERY_STRING'] = $query_string;
            unset($param, $paramc, $query_string);
        }

        // slashes 处理,如果没有魔法引号处理（自动转义），则手动转义GET/POST/COOKIE/FILES中的单双引号、null反斜线\
        if(!MAGIC_QUOTES_GPC) {
            $_GET = daddslashes($_GET);
            $_POST = daddslashes($_POST);
            $_COOKIE = daddslashes($_COOKIE);
            $_FILES = daddslashes($_FILES);
        }

        //cookie 处理
        ///验证cookie前缀与config中的设置值是否一致，一致则转为$cookie数组中的值
        $prelength = strlen($this->config['cookie']['cookiepre']);
        foreach($_COOKIE as $key = $val) {
            if(substr($key, 0, $prelength) == $this->config['cookie']['cookiepre']) {
                $this->var['cookie'][substr($key, $prelength)] = $val;
            }
        }

        $_GET['diy'] = empty($_GET['diy']) ? '' : $_GET['diy'];

        ///$_GET和$_POST转成与索引同名加"gp_"前缀的变量
        ///如$_GET['username']直接用$gp_username来访问
        foreach(array_merge($_POST, $_GET) as $k = $v) {
            $this->var['gp_'.$k] = $v;
        }

        ///根据$_GET['mod']来确定m的值，$this->var为全局数组,gp_为上个语句的附加前缀
        $this->var['mod'] = empty($this->var['gp_mod']) ? '' : htmlspecialchars($this->var['gp_mod']);
        ///如果使用ajax，再判断是post传值或get和xmlhttprequest同时有效
        $this->var['inajax'] = empty($this->var['gp_inajax']) ? 0 : ($_SERVER['REQUEST_METHOD'] == 'GET' && $_SERVER['HTTP_X_REQUESTED_WITH'] == 'XMLHttpRequest' || $_SERVER['REQUEST_METHOD'] == 'POST' ? 1 : 0);
        ///当前页码
        $this->var['page'] = empty($this->var['gp_page']) ? 1 : max(1, intval($this->var['gp_page']));
        ///确定cookie中的sid值
        $this->var['sid'] = $this->var['cookie']['sid'] = isset($this->var['cookie']['sid']) ? htmlspecialchars($this->var['cookie']['sid']) : '';
    }

    ///初始化设置
    function _init_config() {
        ///加载设置文件
        $_config = array();
        @include DISCUZ_ROOT.'./config/config_global.php';
        if(empty($_config)) {
            error('config_notfound');
        }
        ///确定密钥，如果值为空，则密钥默认为cookie前缀与数据库名拼接的md5值，否则为配置文件中的值
        ///authkey密钥是sid等参数加解密的重要参数
        $_config['security']['authkey'] = empty($config['security']['authkey']) ? md5($_config['cookie']['cookiepre'].$_config['db'][1]['dbname']) : ($config['security']['authkey']);

        $this->config = & $_config;
        ///Discuz的调试
        if(empty($this->config['debug']) || !file_exists(libfile('function/debug'))) {
            define('DISCUZ_DEBUG', false);
        } elseif($this->config['debug'] === 1 || $this->config['debug'] === 2 || !empty($_REQUEST['debug']) && $_REQUEST['debug'] === $this->config['debug']) {
            define('DISCUZ_DEBUG', true);
            if($this->config['debug'] == 2) {
                error_reporting(E_ALL);
            }
        }

        $GLOBALS['_G']['config'] = & $this->config;
        ///以浏览器版本为参考，进行密钥的二次md5加密
        $GLOBALS['_G']['authkey'] = md5($this->config['security']['authkey'].$_SERVER['HTTP_USER_AGENT']);
    }

    function _init_output() {
        ///如果设置中打开xss跨站脚本的防御模式，且网址中存在"<"和"""等非法字符，则拒绝请求
        if($this->config['security']['urlxssdefend'] && !empty($_SERVER['REQUEST_URI'])) {
            $temp = urldecode($_SERVER['REQUEST_URI']);
            if(strpos($temp, '<') !== false || strpos($temp, '"') !== false) {
                error('request_tainting');
            }
        }

        ///存在ob_gzhandler则启用输出缓存压缩
        if($this->config['output']['gzip'] && EXT_OBGZIP) {
            ob_start('ob_gzhandler');
            setglobal('gzipcompress', true);
        } else {
            ob_start();
            setglobal('gzipcompress', false);
        }

        ///确定HTML页面编码，及其他编码
        if($this->config['output']['forceheader']) {
            @header('Content-Type: text/html; charset='.$this->config['output']['charset']);
        }

        setglobal('charset', $this->config['output']['charset']);
        define('CHARSET', $this->config['output']['charset']);
    }

    ///拒绝机器人访问
    function reject_robot() {
        if(IS_ROBOT) {
            exit(header("HTTP/1.1 403 Forbidden"));
        }
    }

    ///获取客户端ip，
    function _get_client_ip() {
        $clientip = '';
        ///环境变量客户端ip有值且字符长度大于unknown，则说明该变量有效，确定为客户端ip
        if(getenv('HTTP_CLIENT_IP') && strcasecmp(getenv('HTTP_CLIENT_IP'), 'unknown')) {
            $clientip = getenv('HTTP_CLIENT_IP');
        ///否则取当前浏览用户的网关ip地址
        } elseif(getenv('HTTP_X_FORWARDED_FOR') && strcasecmp(getenv('HTTP_X_FORWARDED_FOR'), 'unknown')) {
            $clientip = getenv('HTTP_X_FORWARDED_FOR');
        ///用户计算机的ip地址
        } elseif(getenv('REMOTE_ADDR') && strcasecmp(getenv('REMOTE_ADDR'), 'unknown')) {
            $clientip = getenv('REMOTE_ADDR');
        } elseif(isset($_SERVER['REMOTE_ADDR']) && $_SERVER['REMOTE_ADDR'] && strcasecmp($_SERVER['REMOTE_ADDR'], 'unknown')) {
            $clientip = $_SERVER['REMOTE_ADDR'];
        }

        ///判断是否是数字与点组成的7-15位字符
        preg_match("/[\d\.]{7,15}/", $clientip, $clientipmatches);
        $clientip = $clientipmatches[0] ? $clientipmatches[0] : 'unknown';
        return $clientip;
    }

    function _init_db() {
        ///生成数据库对象
        $this->db = & DB::object();
        ///加载设置文件并连接数据库
        $this->db->set_config($this->config['db']);
        $this->db->connect();
    }

    function _init_session() {

        $this->session = new discuz_session();

        if($this->init_session)
        {
            ///传入sid，客户端ip与uid作为session判断机制，分新老用户，老用户则查session表，否则创建
            $this->session->init($this->var['cookie']['sid'], $this->var['clientip'], $this->var['uid']);
            $this->var['sid'] = $this->session->sid;
            $this->var['session'] = $this->session->var;

            if($this->var['sid'] != $this->var['cookie']['sid']) {
                dsetcookie('sid', $this->var['sid'], 86400);
            }

            // 首次登陆更新最后访问时间，每隔 10 分钟更新用户最后动作时间
            if($this->var['uid'] && ($this->session->isnew || ($this->session->get('lastactivity') + 600) < TIMESTAMP)) {

                $this->session->set('lastactivity', TIMESTAMP);

                $update = array('lastip' = $this->var['clientip'], 'lastactivity' = TIMESTAMP);
                if($this->session->isnew) {
                    $update['lastvisit'] = TIMESTAMP;
                }
                更新会员状态
                DB::update('common_member_status', $update, "uid='".$this->var['uid']."'");
            }
        }
    }

    function _init_user() {

        if($this->init_user) {
            if($auth = getglobal('auth', 'cookie')) {
                $auth = daddslashes(explode("\t", authcode($auth, 'DECODE')));
            }
            list($discuz_pw, $discuz_uid) = empty($auth) || count($auth) < 2 ? array('', '') : $auth;

            if($discuz_uid) {
                $user = getuserbyuid($discuz_uid);
            }

            if(!empty($user) && $user['password'] == $discuz_pw) {
                $this->var['member'] = $user;
            } else {
                $user = array();
                $this->_init_guest();
            }

            $this->cachelist[] = 'usergroup_'.$this->var['member']['groupid'];
            if($user && $user['adminid']  0 && $user['groupid'] != $user['adminid']) {
                $this->cachelist[] = 'admingroup_'.$this->var['member']['adminid'];
            }

        } else {
            $this->_init_guest();
        }

        if(empty($this->var['cookie']['lastvisit'])) {
            $this->var['member']['lastvisit'] = TIMESTAMP - 3600;
            dsetcookie('lastvisit', TIMESTAMP - 3600, 86400 * 30);
        } else {
            $this->var['member']['lastvisit'] = empty($this->var['cookie']['lastvisit']);
        }

        setglobal('uid', getglobal('uid', 'member'));
        setglobal('username', addslashes(getglobal('username', 'member')));
        setglobal('adminid', getglobal('adminid', 'member'));
        setglobal('groupid', getglobal('groupid', 'member'));
    }

    function _init_guest() {
        setglobal('member', array( 'uid' = 0, 'username' = '', 'groupid' = 7, 'credits' = 0, 'timeoffset' = 9999));
    }

    function _init_cron() {
        if($this->init_cron && $this->init_setting) {
            if($this->var['cache']['cronnextrun'] <= TIMESTAMP) {
                discuz_cron::run();
            }
        }
    }

    function _init_misc() {

        if(!$this->init_misc) {
            return false;
        }
        // 调入核心语言包
        lang('core');

        //处理全局时区设置
        if($this->init_setting && $this->init_user) {
            if(!isset($this->var['member']['timeoffset']) || $this->var['member']['timeoffset'] == 9999 || $this->var['member']['timeoffset'] === '') {
                $this->var['member']['timeoffset'] = $this->var['setting']['timeoffset'];
            }
        }

        $timeoffset = $this->init_setting ? $this->var['member']['timeoffset'] : $this->var['setting']['timeoffset'];
        $this->var['timenow'] = array(
            'time' = dgmdate(TIMESTAMP),
            'offset' = $timeoffset = 0 ? ($timeoffset == 0 ? '' : '+'.$timeoffset) : $timeoffset
        );
        $this->timezone_set($timeoffset);

        $this->var['formhash'] = formhash();
        define('FORMHASH', $this->var['formhash']);

        // 定义风格常量
        if(is_array($this->var['style'])) {
            foreach ($this->var['style'] as $key = $val) {
                $key = strtoupper($key);
                if(!defined($key) && !is_array($val)) {
                    define($key, $val);
                }
            }
        }

        //论坛开关检查
        if($this->var['setting']['**losed'] && !(in_array($this->var['mod'], array('logging', 'seccode')) || getglobal('adminid', 'member') == 1)) {
            $closedreason = DB::result_first("SELECT svalue FROM ".DB::table('common_setting')." WHERE skey='closedreason'");
            showmessage($closedreason ? $closedreason : 'board_closed', NULL, array(), array('login' = 1));
        }

        $this->var['tpp'] = $this->var['setting']['topicperpage'] ? intval($this->var['setting']['topicperpage']) : 20;
        $this->var['ppp'] = $this->var['setting']['postperpage'] ? intval($this->var['setting']['postperpage']) : 10;

        if($this->var['setting']['nocacheheaders']) {
            @header("Expires: -1");
            @header("Cache-Control: no-store, private, post-check=0, pre-check=0, max-age=0", FALSE);
            @header("Pragma: no-cache");
        }

        $lastact = TIMESTAMP."\t".htmlspecialchars(basename($this->var['PHP_SELF']))."\t".htmlspecialchars($this->var['mod']);
        dsetcookie('lastact', $lastact, 86400);

    }

    function _init_setting() {

        if($this->init_setting) {

            if(empty($this->var['setting'])) {
                $this->cachelist[] = 'setting';
            }

            if(empty($this->var['style'])) {
                $this->cachelist[] = 'style_default';
            }

            if(!isset($this->var['cache']['cronnextrun'])) {
                $this->cachelist[] = 'cronnextrun';
            }
        }

        !empty($this->cachelist) && loadcache($this->cachelist);

        if(!is_array($this->var['setting'])) {
            $this->var['setting'] = array();
        }
        if($this->var['member'] && $this->var['member']['adminid']  0 && $this->var['member']['groupid'] != $this->var['member']['adminid'] && !empty($this->var['cache']['admingroup_'.$this->var['member']['adminid']])) {
            $this->var['group'] = array_merge($this->var['group'], $this->var['cache']['admingroup_'.$this->var['member']['adminid']]);
        }
    }

    function _init_memory() {
        $this->mem = new discuz_memory();
        if($this->init_memory) {
            $this->mem->init($this->config['memory']);
        }
        $this->var['memory'] = $this->mem->type;
    }

    function timezone_set($timeoffset = 0) {
        if(function_exists('date_default_timezone_set')) {
            @date_default_timezone_set('Etc/GMT'.($timeoffset  0 ? '-' : '+').(abs($timeoffset)));
        }
    }

    function error($msg, $halt = true) {
        $this->error_log($msg);
        echo $msg;
        $halt && exit();
    }

    function error_log($message) {
        $time = date("Y-m-d H:i:s", TIMESTAMP);
        $file =  DISCUZ_ROOT.'./data/log/errorlog_'.date("Ym").'.txt';
        $message = "\n#{$time}:\t".str_replace(array("\t", "\r", "\n"), " ", $message);
        error_log($message, 3, $file);
    }

}

/**
 * Discuz MySQL 类的支持
 *
 */
class db_mysql
{
    var $tablepre;
    var $version = '';
    var $querynum = 0;
    var $curlink;
    var $link = array();
    var $config = array();
    var $sqldebug = array();

    function db_mysql($config = array()) {
        if(!empty($config)) {
            $this->set_config($config);
        }
    }

    function set_config($config) {
        $this->config = &$config;
        $this->tablepre = $config['1']['tablepre'];
    }

    function connect() {

        if(empty($this->config) || empty($this->config[1])) {
            $this->halt('notfound_config');
        }

        foreach ($this->config as $id = $config) {
            $this->link[$id] = $this->_dbconnect(
            $config['dbhost'],
            $config['dbuser'],
            $config['dbpw'],
            $config['dbcharset'],
            $config['dbname'],
            $config['pconnect']
            );
        }
        $this->curlink = $this->link[1];
    }

    function _dbconnect($dbhost, $dbuser, $dbpw, $dbcharset, $dbname, $pconnect) {
        $link = null;
        $func = empty($pconnect) ? 'mysql_connect' : 'mysql_pconnect';
        if(!$link = @$func($dbhost, $dbuser, $dbpw, 1)) {
            $this->halt('notconnect');
        } else {
            $this->curlink = $link;
            if($this->version()  '4.1') {
                $serverset = $dbcharset ? 'character_set_connection='.$dbcharset.', character_set_results='.$dbcharset.', character_set_client=binary' : '';
                $serverset .= $this->version()  '5.0.1' ? ((empty($serverset) ? '' : ',').'sql_mode=\'\'') : '';
                $serverset && mysql_query("SET $serverset", $link);
            }
            $dbname && @mysql_select_db($dbname, $link);
        }
        return $link;
    }

    function table_name($tablename) {
        return $this->tablepre.$tablename;
    }

    function select_db($dbname) {
        return mysql_select_db($dbname, $this->curlink);
    }

    function fetch_array($query, $result_type = MYSQL_ASSOC) {
        return mysql_fetch_array($query, $result_type);
    }

    function fetch_first($sql) {
        return $this->fetch_array($this->query($sql));
    }

    function result_first($sql) {
        return $this->result($this->query($sql), 0);
    }

    function query($sql, $type = '') {

        if(defined('DISCUZ_DEBUG') && DISCUZ_DEBUG) {
            $starttime = dmicrotime();
        }
        $func = $type == 'UNBUFFERED' && @function_exists('mysql_unbuffered_query') ?
        'mysql_unbuffered_query' : 'mysql_query';
        if(!($query = $func($sql, $this->curlink))) {
            if(in_array($this->errno(), array(2006, 2013)) && substr($type, 0, 5) != 'RETRY') {
                $this->connect();
                return $this->query($sql, 'RETRY'.$type);
            }
            if($type != 'SILENT' && substr($type, 5) != 'SILENT') {
                $this->halt('query_error', $sql);
            }
        }

        if(defined('DISCUZ_DEBUG') && DISCUZ_DEBUG) {
            $this->sqldebug[] = array($sql, number_format((dmicrotime() - $starttime), 6), debug_backtrace());
        }

        $this->querynum++;
        return $query;
    }

    function affected_rows() {
        return mysql_affected_rows($this->curlink);
    }

    function error() {
        return (($this->curlink) ? mysql_error($this->curlink) : mysql_error());
    }

    function errno() {
        return intval(($this->curlink) ? mysql_errno($this->curlink) : mysql_errno());
    }

    function result($query, $row = 0) {
        $query = @mysql_result($query, $row);
        return $query;
    }

    function num_rows($query) {
        $query = mysql_num_rows($query);
        return $query;
    }

    function num_fields($query) {
        return mysql_num_fields($query);
    }

    function free_result($query) {
        return mysql_free_result($query);
    }

    function insert_id() {
        return ($id = mysql_insert_id($this->curlink)) = 0 ? $id : $this->result($this->query("SELECT last_insert_id()"), 0);
    }

    function fetch_row($query) {
        $query = mysql_fetch_row($query);
        return $query;
    }

    function fetch_fields($query) {
        return mysql_fetch_field($query);
    }

    function version() {
        if(empty($this->version)) {
            $this->version = mysql_get_server_info($this->curlink);
        }
        return $this->version;
    }

    function close() {
        return mysql_close($this->curlink);
    }

    function halt($message = '', $sql = '') {
        global $_G;
        $dberror = $this->error();
        $dberrno = $this->errno();
        $phperror = '<table style="font-size:11px" cellpadding="0"><tr><td width="270">File</td><td width="80">Line</td><td>Function</td></tr>';
        foreach (debug_backtrace() as $error) {
            $error['file'] = str_replace(DISCUZ_ROOT, '', $error['file']);
            $error['class'] = isset($error['class']) ? $error['class'] : '';
            $error['type'] = isset($error['type']) ? $error['type'] : '';
            $error['function'] = isset($error['function']) ? $error['function'] : '';
            $phperror .= "<tr><td>$error[file]</td><td>$error[line]</td><td>$error[class]$error[type]$error[function]()</td></tr>";
        }
        $phperror .= '</table>';
        $helplink = "http://faq.comsenz.com/?type=mysql&dberrno=".rawurlencode($dberrno)."&dberror=".rawurlencode($dberror);
        @header('Content-Type: text/html; charset='.$_G['config']['output']['charset']);
        echo '<div style="position:absolute;font-size:11px;font-family:verdana,arial;background:#EBEBEB;padding:0.5em;line-height:1.5em">'.
        error('db_error', array(
            '$message' = error('db_'.$message, array(), true),
            '$info' = $dberror ? error('db_error_message', array('$dberror' = $dberror), true) : '',
            '$sql' = $sql ? error('db_error_sql', array('$sql' = $sql), true) : '',
            '$errorno' = $dberrno ? error('db_error_no', array('$dberrno' = $dberrno), true) : '',
            '$helplink' = $helplink,
            ), true);
        echo "<b>PHP Backtrace</b><br />$phperror<br /></div>";
        exit();
    }

}

/**
 * 对Discuz CORE 中 DB Object中的主要方法进行二次封装，方便程序调用
 *
 */
class DB
{

    /**
     * 返回表名(pre_$table)
     *
     * @param 原始表名 $table
     * @return 增加pre之后的名字
     */
    function table($table) {
        $a = & DB::object();
        return $a->table_name($table);
    }

    /**
     * 删除一条或者多条记录
     *
     * @param string $table 原始表名
     * @param string $condition 条件语句，不需要写WHERE
     * @param int $limit 删除条目数
     * @param boolean $unbuffered 立即返回？
     */
    function delete($table, $condition, $limit = 0, $unbuffered = true) {
        if(empty($condition)) {
            $where = '1';
        } elseif(is_array($condition)) {
            $where = DB::implode_field_value($condition, ' AND ');
        } else {
            $where = $condition;
        }
        $sql = "DELETE FROM ".DB::table($table)." WHERE $where ".($limit ? "LIMIT $limit" : '');
        return DB::query($sql, ($unbuffered ? 'UNBUFFERED' : ''));
    }

    /**
     * 插入一条记录
     *
     * @param string $table 原始表名
     * @param array $data 数组field->vlaue 对
     * @param boolen $return_insert_id 返回 InsertID?
     * @param boolen $replace 是否是REPLACE模式
     * @param boolen $silent 屏蔽错误？
     * @return InsertID or Result
     */
    function insert($table, $data, $return_insert_id = false, $replace = false, $silent = false) {

        $sql = DB::implode_field_value($data);

        $cmd = $replace ? 'REPLACE INTO' : 'INSERT INTO';

        $table = DB::table($table);
        $silent = $silent ? 'SILENT' : '';

        $return = DB::query("$cmd $table SET $sql", $silent);

        return $return_insert_id ? DB::insert_id() : $return;

    }

    /**
     * 更新一条或者多条数据记录
     *
     * @param string $table 原始表名
     * @param array $data 数据field-value
     * @param string $condition 条件语句，不需要写WHERE
     * @param boolean $unbuffered 迅速返回？
     * @param boolan $low_priority 延迟更新？
     * @return result
     */
    function update($table, $data, $condition, $unbuffered = false, $low_priority = false) {
        $sql = DB::implode_field_value($data);
        $cmd = "UPDATE ".($low_priority ? 'LOW_PRIORITY' : '');
        $table = DB::table($table);
        $where = $comma = '';
        if(empty($condition)) {
            $where = '1';
        } elseif(is_array($condition)) {
            $where = DB::implode_field_value($condition, ' AND ');
        } else {
            $where = $condition;
        }
        $res = DB::query("$cmd $table SET $sql WHERE $where", $unbuffered ? 'UNBUFFERED' : '');
        return $res;
    }

    /**
     * 格式化field字段和value，并组成一个字符串
     *
     * @param array $array 格式为 key=value 数组
     * @param 分割符 $glue
     * @return string
     */
    function implode_field_value($array, $glue = ',') {
        //print_r(debug_backtrace());
        $sql = $comma = '';
        foreach ($array as $k = $v) {
            $sql .= $comma."`$k`='$v'";
            $comma = $glue;
        }
        return $sql;
    }

    /**
     * 返回插入的ID
     *
     * @return int
     */
    function insert_id() {
        $db = & DB::object();
        return $db->insert_id();
    }

    /**
     * 依据查询结果，返回一行数据
     *
     * @param resourceID $resourceid
     * @return array
     */
    function fetch($resourceid) {
        $db = & DB::object();
        return $db->fetch_array($resourceid);
    }

    /**
     * 依据SQL文，返回一条查询结果
     *
     * @param string $query 查询语句
     * @return array
     */
    function fetch_first($sql) {
        $db = & DB::object();
        return $db->fetch_first($sql);
    }

    /**
     * 依据查询结果，返回结果数值
     *
     * @param resourceid $resourceid
     * @return string or int
     */
    function result($resourceid, $row = 0) {
        $db = & DB::object();
        return $db->result($resourceid, $row);
    }

    /**
     * 依据查询语句，返回结果数值
     *
     * @param string $query SQL查询语句
     * @return unknown
     */
    function result_first($sql) {
        $db = & DB::object();
        return $db->result_first($sql);
    }

    /**
     * 执行查询
     *
     * @param string $sql
     * @param 类型定义 $type UNBUFFERED OR SILENT
     * @return Resource OR Result
     */
    function query($sql, $type = '') {
        $db = & DB::object();
        return $db->query($sql, $type);
    }

    /**
     * 返回select的结果行数
     *
     * @param resource $resourceid
     * @return int
     */
    function num_rows($resourceid) {
        $db = & DB::object();
        return $db->num_rows($resourceid);
    }

    /**
     * 返回sql语句所影响的记录行数
     *
     * @return int
     */
    function affected_rows() {
        $db = & DB::object();
        return $db->affected_rows();
    }

    function free_result($query) {
        $db = & DB::object();
        return $db->free_result($query);
    }

    function error() {
        $db = & DB::object();
        return $db->error();
    }

    function errno() {
        $db = & DB::object();
        return $db->errno();
    }

    /**
     * 返回 DB object 指针
     *
     * @return pointer of db object from discuz core
     */
    function &object() {
        static $db;
        if(empty($db)) {
            $db = new db_mysql();
        }
        return $db;
    }
}

class discuz_session {

    ///sid,ip1-4, uid, username, groupid组id, invisible隐身与否,action行为,上次活动lastactivity,fid板块id,tid帖子id
    var $sid = null;
    var $var;
    var $isnew = false;
    var $newguest = array('sid' = 0, 'ip1' = 0, 'ip2' = 0, 'ip3' = 0, 'ip4' = 0,
    'uid' = 0, 'username' = '', 'groupid' = 7, 'invisible' = 0, 'action' = 0,
    'lastactivity' = 0, 'fid' = 0, 'tid' = 0);

    var $old =  array('sid' =  '', 'ip' =  '', 'uid' =  0);

    ///与类同名的函数，构造函数，初始化session各值
    function discuz_session($sid = '', $ip = '', $uid = 0) {
        $this->old = array('sid' =  $sid, 'ip' =  $ip, 'uid' =  $uid);
        $this->var = $this->newguest;
        if(!empty($ip)) {
            $this->init($sid, $ip, $uid);
        }
    }
    ///设置$newguest各项值
    function set($key, $value) {
        if(isset($this->newguest[$key])) {
            $this->var[$key] = $value;
        } elseif ($key == 'ip') {
            $ips = explode('.', $value);
            $this->set('ip1', $ips[0]);
            $this->set('ip2', $ips[1]);
            $this->set('ip3', $ips[2]);
            $this->set('ip4', $ips[3]);
        }
    }

    ///获取
    function get($key) {
        if(isset($this->newguest[$key])) {
            return $this->var[$key];
        } elseif ($key == 'ip') {
            return $this->get('ip1').'.'.$this->get('ip2').'.'.$this->get('ip3').'.'.$this->get('ip4');
        }
    }

    ///初始化，sid有值则可能是老用户，去读session表，判断sid，ip符合的值是否存在，存在则赋值给$sid
    function init($sid, $ip, $uid) {
        $this->old = array('sid' =  $sid, 'ip' =  $ip, 'uid' =  $uid);
        $session = array();
        if($sid) {
            $session = DB::fetch_first("SELECT * FROM ".DB::table('common_session').
                " WHERE sid='$sid' AND CONCAT_WS('.', ip1,ip2,ip3,ip4)='$ip'");
        }

        if(empty($session) || $session['uid'] != $uid) {
            $session = $this->create($ip, $uid);
        }

        $this->var = $session;
        $this->sid = $session['sid'];
    }

    ///新用户
    function create($ip, $uid) {

        $this->isnew = true;
        $this->var = $this->newguest;
        $this->set('sid', random(6));
        $this->set('uid', $uid);
        $this->set('ip', $ip);
        $this->set('lastactivity', time());
        $this->sid = $this->var['sid'];

        return $this->var;
    }

    function delete() {

        $onlinehold = 1800; //此数值应当取自全局变量
        $guestspan = 60; //避免游客重复激活sid

        $onlinehold = time() - $onlinehold;
        $guestspan = time() - $guestspan;

        //当前用户的sid
        $condition = " sid='{$this->sid}' ";
        //过期的 session
        $condition .= " OR lastactivity<$onlinehold ";
        //频繁的同一ip游客
        $condition .= " OR (uid='0' AND ip1='{$this->var['ip1']}' AND ip2='{$this->var['ip2']}' AND ip3='{$this->var['ip3']}' AND ip4='{$this->var['ip4']}' AND lastactivity$guestspan) ";
        //当前用户的uid
        $condition .= $this->var['uid'] ? " OR (uid='{$this->var['uid']}') " : '';
        DB::delete('common_session', $condition);
    }

    function update() {
        if($this->sid !== null) {

            $data = daddslashes($this->var);

            if($this->isnew) {
                $this->delete();
                DB::insert('common_session', $data, false, false, true);
            } else {
                DB::update('common_session', $data, "sid='$data[sid]'");
            }
            dsetcookie('sid', $this->sid, 86400);
        }
    }

    /**
     * 取在线用户数量
     *
     * @param int $type 0=全部 1=会员 2=游客
     */
    function onlinecount($type = 0) {
        $condition = $type == 1 ? ' WHERE uid0 ' : ($type == 2 ? ' WHERE invisible=1 ' : '');
        return DB::result_first("SELECT count(*) FROM ".DB::table('common_session').$condition);
    }

}

class discuz_cron
{

    /**
     * 运行cron
     *
     * @param int $cronid 执行某个cron，如果不指定则运行当前需要运行的
     * @return true
     */
    function run($cronid = 0) {

        $timestamp = TIMESTAMP;
        $cron = DB::fetch_first("SELECT * FROM ".DB::table('common_cron')."
                WHERE ".($cronid ? "cronid='$cronid'" : "available'0' AND nextrun<='$timestamp'")."
                ORDER BY nextrun LIMIT 1");

        $processname ='DZ_CRON_'.(empty($cron) ? 'CHECKER' : $cron['cronid']);

        if(!discuz_process::create($processname, 600)) {
            return false;
        }

        if($cron) {

            $cron['filename'] = str_replace(array('..', '/', '\\'), '', $cron['filename']);
            $cronfile = DISCUZ_ROOT.'./source/include/cron/'.$cron['filename'];

            $cron['minute'] = explode("\t", $cron['minute']);
            discuz_cron::setnextime($cron);

            @set_time_limit(1000);
            @ignore_user_abort(TRUE);

            if(!@include $cronfile) {
                //debug('CRON', $cron['name'].' : Cron script('.$cron['filename'].') not found or syntax error', 0);
            }
        }

        discuz_cron::nextcron();
        discuz_process::delete($processname);
        return true;
    }

    /**
     * 设定下一个计划任务将要执行的时间 here...
     *
     */
    function nextcron() {
        $nextrun = DB::result_first("SELECT nextrun FROM ".DB::table('common_cron')." WHERE available>'0' ORDER BY nextrun LIMIT 1");
        if($nextrun !== FALSE) {
            save_syscache('cronnextrun', $nextrun);
        } else {
            save_syscache('cronnextrun', TIMESTAMP + 86400 * 365);
        }
        return true;
    }

    /**
     * 设定某个计划任务下次执行时间
     *
     * @param array $cron
     * @return true
     */
    function setnextime($cron) {

        global $_G;

        if(empty($cron)) return FALSE;

        list($yearnow, $monthnow, $daynow, $weekdaynow, $hournow, $minutenow) = explode('-', gmdate('Y-m-d-w-H-i', TIMESTAMP + $_G['setting']['timeoffset'] * 3600));

        if($cron['weekday'] == -1) {
            if($cron['day'] == -1) {
                $firstday = $daynow;
                $secondday = $daynow + 1;
            } else {
                $firstday = $cron['day'];
                $secondday = $cron['day'] + gmdate('t', TIMESTAMP + $_G['setting']['timeoffset'] * 3600);
            }
        } else {
            $firstday = $daynow + ($cron['weekday'] - $weekdaynow);
            $secondday = $firstday + 7;
        }

        if($firstday < $daynow) {
            $firstday = $secondday;
        }

        if($firstday == $daynow) {
            $todaytime = discuz_cron::todaynextrun($cron);
            if($todaytime['hour'] == -1 && $todaytime['minute'] == -1) {
                $cron['day'] = $secondday;
                $nexttime = discuz_cron::todaynextrun($cron, 0, -1);
                $cron['hour'] = $nexttime['hour'];
                $cron['minute'] = $nexttime['minute'];
            } else {
                $cron['day'] = $firstday;
                $cron['hour'] = $todaytime['hour'];
                $cron['minute'] = $todaytime['minute'];
            }
        } else {
            $cron['day'] = $firstday;
            $nexttime = discuz_cron::todaynextrun($cron, 0, -1);
            $cron['hour'] = $nexttime['hour'];
            $cron['minute'] = $nexttime['minute'];
        }

        $nextrun = @gmmktime($cron['hour'], $cron['minute'] > 0 ? $cron['minute'] : 0, 0, $monthnow, $cron['day'], $yearnow) - $_G['setting']['timeoffset'] * 3600;

        $availableadd = $nextrun  TIMESTAMP ? '' : ', available=\'0\'';
        DB::query("UPDATE ".DB::table('common_cron')." SET lastrun='$_G[timestamp]', nextrun='$nextrun' $availableadd WHERE cronid='$cron[cronid]'");

        return true;
    }

    /**
     * 计算计划任务今日执行状态
     *
     * @param int $cron
     * @param int $hour
     * @param int $minute
     * @return int
     */
    function todaynextrun($cron, $hour = -2, $minute = -2) {
        global $_G;

        $hour = $hour == -2 ? gmdate('H', TIMESTAMP + $_G['setting']['timeoffset'] * 3600) : $hour;
        $minute = $minute == -2 ? gmdate('i', TIMESTAMP + $_G['setting']['timeoffset'] * 3600) : $minute;

        $nexttime = array();
        if($cron['hour'] == -1 && !$cron['minute']) {
            $nexttime['hour'] = $hour;
            $nexttime['minute'] = $minute + 1;
        } elseif($cron['hour'] == -1 && $cron['minute'] != '') {
            $nexttime['hour'] = $hour;
            if(($nextminute = discuz_cron::nextminute($cron['minute'], $minute)) === false) {
                ++$nexttime['hour'];
                $nextminute = $cron['minute'][0];
            }
            $nexttime['minute'] = $nextminute;
        } elseif($cron['hour'] != -1 && $cron['minute'] == '') {
            if($cron['hour'] < $hour) {
                $nexttime['hour'] = $nexttime['minute'] = -1;
            } elseif($cron['hour'] == $hour) {
                $nexttime['hour'] = $cron['hour'];
                $nexttime['minute'] = $minute + 1;
            } else {
                $nexttime['hour'] = $cron['hour'];
                $nexttime['minute'] = 0;
            }
        } elseif($cron['hour'] != -1 && $cron['minute'] != '') {
            $nextminute = discuz_cron::nextminute($cron['minute'], $minute);
            if($cron['hour'] &lt; $hour || ($cron['hour'] == $hour && $nextminute === false)) {
                $nexttime['hour'] = -1;
                $nexttime['minute'] = -1;
            } else {
                $nexttime['hour'] = $cron['hour'];
                $nexttime['minute'] = $nextminute;
            }
        }

        return $nexttime;
    }

    /**
     * 计算计划任务执行时刻
     *
     * @param int $nextminutes
     * @param int $minutenow
     * @return int
     */
    function nextminute($nextminutes, $minutenow) {
        foreach($nextminutes as $nextminute) {
            if($nextminute > $minutenow) {
                return $nextminute;
            }
        }
        return false;
    }
}

/**
 * 功能进程管理
 * 通常用于某些功能禁止?⒎⒃诵?
 *
 */

class discuz_process
{

    /**
     * 获取某进程信息
     *
     * @param string $name 进程名字
     * @return array
     */
    function get($name) {
        $name5 = md5($name);
        $res = DB::fetch_first("SELECT * FROM ".DB::table('common_process')." WHERE processid='$name5'");

        if(empty($res)) {
            $res = array();
        } elseif($res['expiry'] < TIMESTAMP) {
            discuz_process::delete($name);
            $res = array();
        }
        return $res;
    }

    /**
     * 创建进程
     *
     * @param string $name 进程名
     * @param int $lifespan 进程过期时间
     * @param int $extra 进程附属信息
     * @return boolean
     */
    function create($name, $lifespan = 0, $extra = 0) {
        $check = discuz_process::get($name);
        if(empty($check)) {
            $lifespan = empty($lifespan) ? 600 : $lifespan;
            DB::insert('common_process', array(
                'processid' => md5($name),
                'expiry' = TIMESTAMP + $lifespan,
                'extra' =$extra), false, true);
            return true;
        }
        else {
            return false;
        }
    }

    /**
     * 删除某个进程或过期进程
     *
     * @param string $name 进程名
     */
    function delete($name = '') {
        $name = md5($name);
        DB::delete('common_process', "processid='$name' OR expiry<".TIMESTAMP);
    }

}

/**
 * Discuz 内存读写引擎
 * 支持 memcache, eAccelerator, XCache
 *
 * 使用的时候建议直接利用函数 memory()
 */
class discuz_memory
{
    var $config;
    var $extension = array();
    var $memory;
    var $prefix;
    var $type;
    var $keys;
    var $enable = false;

    /**
     * 确认当前系统支持的内存读写接口
     * @return discuz_memory
     */
    function discuz_memory() {
        $this->extension['eaccelerator'] = extension_loaded('eAccelerator');
        $this->extension['xcache'] = extension_loaded('XCache');
        $this->extension['memcache'] = extension_loaded('memcache');
    }

    /**
     * 依据config当中设置，初始化内存引擎
     * @param unknown_type $config
     */
    function init($config) {

        $this->config = $config;<span style="font-family: Courier New;"><span style="color: #007700;">&nbsp;</span><span style="color: #ff8000;">//这里的$config能追溯到discuz_core的构造函数，就是把config_global.php的数据加载进来</span></span>
        $this->prefix = empty($config['prefix']) ? substr(md5($_SERVER['HTTP_HOST']), 0, 6).'_' : $config['prefix'];
        $this->keys = array();

        // memcache 接口
        if($this->extension['memcache'] && !empty($config['memcache']['server'])) {
            require_once libfile('class/memcache');
            $this->memory = new discuz_memcache();
            $this->memory->init($this->config['memcache']);
            if(!$this->memory->enable) {
                $this->memory = null;
            }
        }

        // eaccelerator 接口
        if(!is_object($this->memory) && $this->extension['eaccelerator'] && $this->config['eaccelerator']) {
            require_once libfile('class/eaccelerator');
            $this->memory = new discuz_eaccelerator();
            $this->memory->init(null);
        }

        // xcache 接口
        if(!is_object($this->memory) && $this->extension['xcache'] && $this->config['xcache']) {
            require_once libfile('class/xcache');
            $this->memory = new discuz_xcache();
            $this->memory->init(null);
        }

        // 当接口正常，引入当前已经缓存的变量数组
        if(is_object($this->memory)) {
            $this->enable = true;
            $this->type = str_replace('discuz_', '', get_class($this->memory));
            $this->keys = $this->get('memory_system_keys');
            $this->keys = !is_array($this->keys) ? array() : $this->keys;
        }

    }

    /**
     * 读取内存
     *
     * @param string $key
     * @return mix
     */
    function get($key) {
        $ret = null;
        if($this->enable && (isset($this->keys[$key]) || $key == 'memory_system_keys')) {
            $ret = $this->memory->get($this->_key($key));
            if(!is_array($ret)) {
                $ret = null;
            } else {
                return $ret[0];
            }
        }
        return $ret;
    }

    /**
     * 写入内存
     *
     * @param string $key
     * @param array_string_number $value
     * @param int过期时间 $ttl
     * @return boolean
     */
    function set($key, $value, $ttl = 0) {

        $ret = null;
        if($this->enable) {
            $ret = $this->memory->set($this->_key($key), array($value), $ttl);
            if($ret) {
                $this->keys[$key] = true;
                $this->memory->set($this->_key('memory_system_keys'), array($this->keys));
            }
        }
        return $ret;
    }

    /**
     * 删除一个内存单元
     * @param 键值string $key
     * @return boolean
     */
    function rm($key) {
        $ret = null;
        if($this->enable) {
            $ret = $this->memory->rm($this->_key($key));
            if($ret) {
                unset($this->keys[$key]);
                $this->memory->set($this->_key('memory_system_keys'), array($this->keys));
            }
        }
        return $ret;
    }

    /**
     * 清除当前使用的所有内存
     */
    function clear() {
        if($this->enable && is_array($this->keys)) {
            $this->keys['memory_system_keys'] = true;
            foreach ($this->keys as $k = $v) {
                $this->memory->rm($this->_key($k));
            }
        }
        $this->keys = array();
        return true;
    }

    /**
     * 内部函数 追加键值前缀
     * @param string $str
     * @return boolean
     */
    function _key($str) {
        return ($this->prefix).$str;
    }

}