Yii分析11：Yii核心组件之异常处理类CErrorHandler

abstract class CApplication extends CModule
	public function __construct($config=null)
	{
		……
		//初始化系统处理函数
		$this->initSystemHandlers();
		$this->registerCoreComponents();
		……
	}
	protected function initSystemHandlers()
	{
		if(YII_ENABLE_EXCEPTION_HANDLER)
			//设置异常处理函数
			set_exception_handler(array($this,'handleException'));
		if(YII_ENABLE_ERROR_HANDLER)
			//设置错误处理函数
			set_error_handler(array($this,'handleError'),error_reporting());
	}
	//错误处理函数
	public function handleError($code,$message,$file,$line)
	{
		if($code & error_reporting())
		{
			// disable error capturing to avoid recursive errors
			restore_error_handler();
			restore_exception_handler();

			$log="$message ($file:$line)\nStack trace:\n";
			$trace=debug_backtrace();
			// skip the first 3 stacks as they do not tell the error position
			if(count($trace)>3)
				$trace=array_slice($trace,3);
			foreach($trace as $i=>$t)
			{
				if(!isset($t['file']))
					$t['file']='unknown';
				if(!isset($t['line']))
					$t['line']=0;
				if(!isset($t['function']))
					$t['function']='unknown';
				$log.="#$i {$t['file']}({$t['line']}): ";
				if(isset($t['object']) && is_object($t['object']))
					$log.=get_class($t['object']).'->';
				$log.="{$t['function']}()\n";
			}
			if(isset($_SERVER['REQUEST_URI']))
				$log.='REQUEST_URI='.$_SERVER['REQUEST_URI'];
			Yii::log($log,CLogger::LEVEL_ERROR,'php');

			try
			{
				Yii::import('CErrorEvent',true);
				$event=new CErrorEvent($this,$code,$message,$file,$line);
				$this->onError($event);
				if(!$event->handled)
				{
					// try an error handler
					//如果注册了错误处理类，使用错误处理类来处理，否则直接显示错误
					if(($handler=$this->getErrorHandler())!==null)
						$handler->handle($event);
					else
						$this->displayError($code,$message,$file,$line);
				}
			}
			catch(Exception $e)
			{
				$this->displayException($e);
			}

			try
			{
				$this->end(1);
			}
			catch(Exception $e)
			{
				// use the most primitive way to log error
				$msg = get_class($e).': '.$e->getMessage().' ('.$e->getFile().':'.$e->getLine().")\n";
				$msg .= $e->getTraceAsString()."\n";
				$msg .= "Previous error:\n";
				$msg .= $log."\n";
				$msg .= '$_SERVER='.var_export($_SERVER,true);
				error_log($msg);
				exit(1);
			}
		}
	}
	//异常处理函数
	public function handleException($exception)
	{
		// disable error capturing to avoid recursive errors
		restore_error_handler();
		restore_exception_handler();

		$category='exception.'.get_class($exception);
		if($exception instanceof CHttpException)
			$category.='.'.$exception->statusCode;
		// php <5.2 doesn't support string conversion auto-magically
		$message=$exception->__toString();
		if(isset($_SERVER['REQUEST_URI']))
			$message.=' REQUEST_URI='.$_SERVER['REQUEST_URI'];
		Yii::log($message,CLogger::LEVEL_ERROR,$category);

		try
		{
			$event=new CExceptionEvent($this,$exception);
			$this->onException($event);
			if(!$event->handled)
			{
				// try an error handler
				if(($handler=$this->getErrorHandler())!==null)
					$handler->handle($event);
				else
					$this->displayException($exception);
			}
		}
		catch(Exception $e)
		{
			$this->displayException($e);
		}

		try
		{
			$this->end(1);
		}
		catch(Exception $e)
		{
			// use the most primitive way to log error
			$msg = get_class($e).': '.$e->getMessage().' ('.$e->getFile().':'.$e->getLine().")\n";
			$msg .= $e->getTraceAsString()."\n";
			$msg .= "Previous exception:\n";
			$msg .= get_class($exception).': '.$exception->getMessage().' ('.$exception->getFile().':'.$exception->getLine().")\n";
			$msg .= $exception->getTraceAsString()."\n";
			$msg .= '$_SERVER='.var_export($_SERVER,true);
			error_log($msg);
			exit(1);
		}
	}