discuz代码阅读-核心类-class_core.php

source/class/class_core.php 是 Discuz! 的通用初始化模块程序，其几乎被所有的外部代码所引用。下面为代码解析

<?php
 
/**
 *      [Discuz!] (C)2001-2099 Comsenz Inc.
 *      This is NOT a freeware, use is subject to license terms
 *
 *      $Id: class_core.php 31312 2012-08-10 03:33:54Z zhangguosheng $
 */
 
/*
error_reporting() 设置 PHP 的报错级别并返回当前级别。
 */
error_reporting(E_ALL);
 
 
/*
定义一个IN_DISCUZ为真，这个IN_DISCUZ常量的作用就是在其他inc这样的包含文件中防止被非法引用，一旦没有这个常量的话就出现Access Denied这样的字样然后退出。
 */
define('IN_DISCUZ', true);
/*
读取社区程序所在绝对路径，存放于常量 DISCUZ_ROOT 中。
 */
define('DISCUZ_ROOT', substr(dirname(__FILE__), 0, -12));
 
define('DISCUZ_CORE_DEBUG', false);
define('DISCUZ_TABLE_EXTENDABLE', TRUE);
 
/* 
用户自定义未捕获异常处理函数为core类中的handleException方法函数
*/
set_exception_handler(array('core', 'handleException'));
 
if(DISCUZ_CORE_DEBUG) {
	set_error_handler(array('core', 'handleError'));
	register_shutdown_function(array('core', 'handleShutdown'));
}
 
if(function_exists('spl_autoload_register')) {
	spl_autoload_register(array('core', 'autoload'));
} else {
	function __autoload($class) {
		return core::autoload($class);
	}
}
 
C::creatapp();
 
class core
{
	private static $_tables;
	private static $_imports;
	private static $_app;
	private static $_memory;
	/*
	通过静态方法调用，返回静态方法所属类的成员对象
	 */
	public static function app() {
		return self::$_app;
	}
	/*
	实例化对象$_app，将discuz_application实例化赋值给$_app,discuz_application实例化非常重要，全局变量$_G,就是在这里初始化的，创建 discuz_application 实例：进行核心的初始化操作，主要有加载配置文件、加载环境变量、连接数据库、加载setting信息、初始化用户数据、session的初始、计划任务等
	 */
	public static function creatapp() {
		if(!is_object(self::$_app)) {
			self::$_app = discuz_application::instance();
		}
		return self::$_app;
	}
	/*
	通过 C::t 方法来调用数据层对应表的对象来实现对数据的操作
	 */
	public static function t($name) {
		return self::_make_obj($name, 'table', DISCUZ_TABLE_EXTENDABLE);
	}
	/*
	modle 模型
	 */
	public static function m($name) {
		$args = array();
		if(func_num_args() > 1) {
			$args = func_get_args();
			unset($args[0]);
		}
		return self::_make_obj($name, 'model', true, $args);
	}
	/*
	创建模型对象
	 */
	protected static function _make_obj($name, $type, $extendable = true, $p = array()) {
		$pluginid = null;
		if($name[0] === '#') {
			list(, $pluginid, $name) = explode('#', $name);
		}
		$cname = $type.'_'.$name;
		if(!isset(self::$_tables[$cname])) {
			if(!class_exists($cname, false)) {
				self::import(($pluginid ? 'plugin/'.$pluginid : 'class').'/'.$type.'/'.$name);
			}
			if($extendable) {
				self::$_tables[$cname] = new discuz_container();
				switch (count($p)) {
					case 0:	self::$_tables[$cname]->obj = new $cname();break;
					case 1:	self::$_tables[$cname]->obj = new $cname($p[1]);break;
					case 2:	self::$_tables[$cname]->obj = new $cname($p[1], $p[2]);break;
					case 3:	self::$_tables[$cname]->obj = new $cname($p[1], $p[2], $p[3]);break;
					case 4:	self::$_tables[$cname]->obj = new $cname($p[1], $p[2], $p[3], $p[4]);break;
					case 5:	self::$_tables[$cname]->obj = new $cname($p[1], $p[2], $p[3], $p[4], $p[5]);break;
					default: $ref = new ReflectionClass($cname);self::$_tables[$cname]->obj = $ref->newInstanceArgs($p);unset($ref);break;
				}
			} else {
				self::$_tables[$cname] = new $cname();
			}
		}
		return self::$_tables[$cname];
	}
	/*
	初始化缓存
	 */
	public static function memory() {
		if(!self::$_memory) {
			self::$_memory = new discuz_memory();
			self::$_memory->init(self::app()->config['memory']);
		}
		return self::$_memory;
	}
	/*
	类文件引入函数，autoload使用该函数
	 */
	public static function import($name, $folder = '', $force = true) {
		$key = $folder.$name;
		if(!isset(self::$_imports[$key])) {
			$path = DISCUZ_ROOT.'/source/'.$folder;
			if(strpos($name, '/') !== false) {
				$pre = basename(dirname($name));
				$filename = dirname($name).'/'.$pre.'_'.basename($name).'.php';
			} else {
				$filename = $name.'.php';
			}
 
			if(is_file($path.'/'.$filename)) {
				self::$_imports[$key] = true;
				$rt = include $path.'/'.$filename;
				return $rt;
			} elseif(!$force) {
				return false;
			} else {
				throw new Exception('Oops! System file lost: '.$filename);
			}
		}
		return true;
	}
	/*
		异常处理
	 */
	public static function handleException($exception) {
		discuz_error::exception_error($exception);
	}
 
	/*
		error处理
	 */
	public static function handleError($errno, $errstr, $errfile, $errline) {
		if($errno & DISCUZ_CORE_DEBUG) {
			discuz_error::system_error($errstr, false, true, false);
		}
	}
	/*
		关闭处理
	 */
	public static function handleShutdown() {
		if(($error = error_get_last()) && $error['type'] & DISCUZ_CORE_DEBUG) {
			discuz_error::system_error($error['message'], false, true, false);
		}
	}
	/*
	自动加载类的方法
	 */
	public static function autoload($class) {
		$class = strtolower($class);
		if(strpos($class, '_') !== false) {
			list($folder) = explode('_', $class);
			$file = 'class/'.$folder.'/'.substr($class, strlen($folder) + 1);
		} else {
			$file = 'class/'.$class;
		}
 
		try {
 
			self::import($file);
			return true;
 
		} catch (Exception $exc) {
 
			$trace = $exc->getTrace();
			foreach ($trace as $log) {
				if(empty($log['class']) && $log['function'] == 'class_exists') {
					return false;
				}
			}
			discuz_error::exception_error($exc);
		}
	}
 
	public static function analysisStart($name){
		$key = 'other';
		if($name[0] === '#') {
			list(, $key, $name) = explode('#', $name);
		}
		if(!isset($_ENV['analysis'])) {
			$_ENV['analysis'] = array();
		}
		if(!isset($_ENV['analysis'][$key])) {
			$_ENV['analysis'][$key] = array();
			$_ENV['analysis'][$key]['sum'] = 0;
		}
		$_ENV['analysis'][$key][$name]['start'] = microtime(TRUE);
		$_ENV['analysis'][$key][$name]['start_memory_get_usage'] = memory_get_usage();
		$_ENV['analysis'][$key][$name]['start_memory_get_real_usage'] = memory_get_usage(true);
		$_ENV['analysis'][$key][$name]['start_memory_get_peak_usage'] = memory_get_peak_usage();
		$_ENV['analysis'][$key][$name]['start_memory_get_peak_real_usage'] = memory_get_peak_usage(true);
	}
 
	public static function analysisStop($name) {
		$key = 'other';
		if($name[0] === '#') {
			list(, $key, $name) = explode('#', $name);
		}
		if(isset($_ENV['analysis'][$key][$name]['start'])) {
			$diff = round((microtime(TRUE) - $_ENV['analysis'][$key][$name]['start']) * 1000, 5);
			$_ENV['analysis'][$key][$name]['time'] = $diff;
			$_ENV['analysis'][$key]['sum'] = $_ENV['analysis'][$key]['sum'] + $diff;
			unset($_ENV['analysis'][$key][$name]['start']);
			$_ENV['analysis'][$key][$name]['stop_memory_get_usage'] = memory_get_usage();
			$_ENV['analysis'][$key][$name]['stop_memory_get_real_usage'] = memory_get_usage(true);
			$_ENV['analysis'][$key][$name]['stop_memory_get_peak_usage'] = memory_get_peak_usage();
			$_ENV['analysis'][$key][$name]['stop_memory_get_peak_real_usage'] = memory_get_peak_usage(true);
		}
		return $_ENV['analysis'][$key][$name];
	}
}
 
class C extends core {}
class DB extends discuz_database {}
 
?>