【discuzX2】/source/class/class_core.php文件中数据库操作类DB及db_mysql分析

<?php
/**
* Discuz MySQL 类的支持 程序中一般不直接使用此类,而是使用DB类，DB类对db_mysql类中的方法又进行了二次封装
*
*/
class db_mysql
{
var $tablepre;
var $version = '';
var $querynum = 0;
var $slaveid = 0;
var $curlink;
var $link = array();
var $config = array();
var $sqldebug = array();
var $map = array();

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

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

function connect($serverid = 1) {

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

$this->link[$serverid] = $this->_dbconnect(
$this->config[$serverid]['dbhost'],
$this->config[$serverid]['dbuser'],
$this->config[$serverid]['dbpw'],
$this->config[$serverid]['dbcharset'],
$this->config[$serverid]['dbname'],
$this->config[$serverid]['pconnect']
);
$this->curlink = $this->link[$serverid];

}

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') {
$dbcharset = $dbcharset ? $dbcharset : $this->config[1]['dbcharset'];
$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($tablename) {
if(!empty($this->map) && !empty($this->map[$tablename])) {
$id = $this->map[$tablename];
if(!$this->link[$id]) {
$this->connect($id);
}
$this->curlink = $this->link[$id];
return $this->config[$id]['tablepre'].$tablename;
} else {
$this->curlink = $this->link[1];
}
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 = '', $sql = '') {
require_once libfile('class/error');
discuz_error::db_error($message, $sql);
}

}

/**
* 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) {
return DB::_execute('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);
$where = '';
if(empty($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 = ',') {
$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() {
return DB::_execute('insert_id');
}

/**
* 依据查询结果，返回一行数据
*
* @param resourceID $resourceid
* @return array
*/
function fetch($resourceid, $type = MYSQL_ASSOC) {
return DB::_execute('fetch_array', $resourceid, $type);
}

/**
* 依据SQL语句，返回第一条查询结果
*
* @param string $query 查询语句
* @return array
*/
function fetch_first($sql) {
DB::checkquery($sql);
return DB::_execute('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) {
return DB::_execute('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::checkquery($sql);
return DB::_execute('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, $type = '') {
DB::checkquery($sql);
return DB::_execute('query', $sql, $type);
}

/**
* 返回select的结果行数
*
* @param resource $resourceid
* @return int
*/
function num_rows($resourceid) {
return DB::_execute('num_rows', $resourceid);
}

/**
* 返回sql语句所影响的记录行数
*
* @return int
*/
function affected_rows() {
return DB::_execute('affected_rows');
}

function free_result($query) {
return DB::_execute('free_result', $query);
}

function error() {
return DB::_execute('error');
}

function errno() {
return DB::_execute('errno');
}

function _execute($cmd , $arg1 = '', $arg2 = '') {//DB类中的很多方法都调用了此方法，此方法又调用了 &object()方法，详情请查看&object()方法，其实&object()方法返回一个db_mysql类的实例化对象，而且是statics类型的实例化对象
static $db;
if(empty($db)) $db = & DB::object();//返回db_mysql操作类的实例化对象
$res = $db->$cmd($arg1, $arg2);
return $res;
}

/**
* 返回 DB object 指针
*
* @return pointer of db object from discuz core
*/
function &object($dbclass = 'db_mysql') {
static $db;
if(empty($db)) $db = new $dbclass();//返回db_mysql数据库操作类的一个statics类型的实例化对象
return $db;
}

function checkquery($sql) {
static $status = null, $checkcmd = array('SELECT', 'UPDATE', 'INSERT', 'REPLACE', 'DELETE');
if($status === null) $status = getglobal('config/security/querysafe/status');
if($status) {
$cmd = trim(strtoupper(substr($sql, 0, strpos($sql, ' '))));
if(in_array($cmd, $checkcmd)) {
$test = DB::_do_query_safe($sql);
if($test < 1) DB::_execute('halt', 'security_error', $sql);
}
}
return true;
}

function _do_query_safe($sql) {
static $_CONFIG = null;
if($_CONFIG === null) {
$_CONFIG = getglobal('config/security/querysafe');
}

$sql = str_replace(array('\\\\', '\\\'', '\\"', '\'\''), '', $sql);
$mark = $clean = '';
if(strpos($sql, '/') === false && strpos($sql, '#') === false && strpos($sql, '-- ') === false) {
$clean = preg_replace("/'(.+?)'/s", '', $sql);
} else {
$len = strlen($sql);
$mark = $clean = '';
for ($i = 0; $i <$len; $i++) {
$str = $sql[$i];
switch ($str) {
case '\'':
if(!$mark) {
$mark = '\'';
$clean .= $str;
} elseif ($mark == '\'') {
$mark = '';
}
break;
case '/':
if(empty($mark) && $sql[$i+1] == '*') {
$mark = '/*';
$clean .= $mark;
$i++;
} elseif($mark == '/*' && $sql[$i -1] == '*') {
$mark = '';
$clean .= '*';
}
break;
case '#':
if(empty($mark)) {
$mark = $str;
$clean .= $str;
}
break;
case "\n":
if($mark == '#' || $mark == '--') {
$mark = '';
}
break;
case '-':
if(empty($mark)&& substr($sql, $i, 3) == '-- ') {
$mark = '-- ';
$clean .= $mark;
}
break;

default:

break;
}
$clean .= $mark ? '' : $str;
}
}

$clean = preg_replace("/[^a-z0-9_\-\(\)#\*\/\"]+/is", "", strtolower($clean));

if($_CONFIG['afullnote']) {
$clean = str_replace('/**/','',$clean);
}

if(is_array($_CONFIG['dfunction'])) {
foreach($_CONFIG['dfunction'] as $fun) {
if(strpos($clean, $fun.'(') !== false) return '-1';
}
}

if(is_array($_CONFIG['daction'])) {
foreach($_CONFIG['daction'] as $action) {
if(strpos($clean,$action) !== false) return '-3';
}
}

if($_CONFIG['dlikehex'] && strpos($clean, 'like0x')) {
return '-2';
}

if(is_array($_CONFIG['dnote'])) {
foreach($_CONFIG['dnote'] as $note) {
if(strpos($clean,$note) !== false) return '-4';
}
}

return 1;

}

}
?>