CodeIgniter源代码阅读（二）Exceptions.php
<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
* CodeIgniter
*
* An open source application development framework for PHP 5.1.6 or newer
*
* @package CodeIgniter
* @author ExpressionEngine Dev Team
* @copyright Copyright (c) 2008 - 2011, EllisLab, Inc.
* @license http://codeigniter.com/user_guide/license.html
* @link http://codeigniter.com
* @since Version 1.0
* @filesource
*/
// ------------------------------------------------------------------------
/**
* Common Functions
*
* Loads the base classes and executes the request.
*
* @package CodeIgniter
* @subpackage codeigniter
* @category Common Functions
* @author ExpressionEngine Dev Team
* @link http://codeigniter.com/user_guide/
*/
// ------------------------------------------------------------------------
/**
* Determines if the current version of PHP is greater then the supplied value
*
* Since there are a few places where we conditionally test for PHP > 5
* we'll set a static variable.
*
* @access public
* @param string
* @return bool TRUE if the current version is $version or higher
*/
if ( ! function_exists('is_php'))//判断当前php版本是否高于支持的版本
{
function is_php($version = '5.0.0')
{
static $_is_php;
$version = (string)$version;
if ( ! isset($_is_php[$version]))
{
// version_compare :Compares two "PHP-standardized" version number strings
$_is_php[$version] = (version_compare(PHP_VERSION, $version) < 0) ? FALSE : TRUE;
}
return $_is_php[$version];
}
}
// ------------------------------------------------------------------------
/**
* Tests for file writability
*
* is_writable() returns TRUE on Windows servers when you really can't write to
* the file, based on the read-only attribute. is_writable() is also unreliable
* on Unix servers if safe_mode is on.
*
* @access private
* @return void
*/
if ( ! function_exists('is_really_writable'))
{
function is_really_writable($file)
{
//DIRECTORY_SEPARATOR是系统的目录分割符。利用它的值可以知道当前是不是linux系统
// If we're on a Unix server with safe_mode off we call is_writable
if (DIRECTORY_SEPARATOR == '/' AND @ini_get("safe_mode") == FALSE)//
{
//如果是linux系统的话，那么可以直接调用此方法来判断文件是否可写
return is_writable($file);
}
// For windows servers and safe_mode "on" installations we'll actually
// write a file then read it. Bah...
//如果是windows系统，则尝试写入一个文件来判断。
if (is_dir($file))
{
//如果是目录，则创建一个随机命名的文件
$file = rtrim($file, '/').'/'.md5(mt_rand(1,100).mt_rand(1,100));
//如果文件不能创建，则返回不可写。
if (($fp = @fopen($file, FOPEN_WRITE_CREATE)) === FALSE)
{
return FALSE;
}
fclose($fp);
@chmod($file, DIR_WRITE_MODE);
@unlink($file);//删除刚才的文件
return TRUE;
}
elseif ( ! is_file($file) OR ($fp = @fopen($file, FOPEN_WRITE_CREATE)) === FALSE)
{
return FALSE;//如果是一个文件，而通过写入方式打不开，则返回不可写
}
fclose($fp);
return TRUE;
}
}
// ------------------------------------------------------------------------
/**
* 为什么还要定义这些全局函数呢？比如说，下面有很多函数，如get_config()、config_item()这两个方法不是应该由
* core/Config.php这个组件去做么？那个load_class()不应该由core/Loader.php去做么？ 把这些函数定义出来貌似
* 感觉架构变得不那么优雅，有点多余。
* 其实是出于这样一种情况：
* 比如说，如果一切和配置有关的动作都由Config组件来完成，一切加载的动作都由Loader来完成，
* 试想一下，如果我要加载Config组件，那么，必须得通过Loader来加载，所以Loader必须比Config要更早实例化，
* 但是如果Loader实例化的时候需要一些和Loader有关的配置信息才能实例化呢？那就必须通过Config来为它取得配置信息。
* 这里就出现了鸡和鸡蛋的问题。。
* 我之前写自己的框架也纠结过这样的问题，后来参考了YII框架，发现它里面其实都有同样的问题，它里面有个Exception的组件，
* 但是在加载这个Exception组件之前，在加载其它组件的时候，如果出错了，那谁来处理异常和错误信息呢？答案就是先定义一些公共的函数。
* 所以这些公共函数就很好地解决了这个问题，这也是为什么Common.php要很早被引入。
*
*/
/**
* Class registry
*
* This function acts as a singleton. If the requested class does not
* exist it is instantiated and set to a static variable. If it has
* previously been instantiated the variable is returned.
*
* @access public
* @param string the class name being requested
* @param string the directory where the class should be found
* @param string the class name prefix
* @return object
*
*/
if ( ! function_exists('load_class'))//CI的类的单例模式的加载
{
//加载类。默认是加载libraries里面的，如果要加载核心组件，$directory就为'core'
function &load_class($class, $directory = 'libraries', $prefix = 'CI_')
{
static $_classes = array();//静态数组 //用一个静态数组，保存已经加载过的类的实例，防止多次实例消耗资源，实现单例化。
// Does the class exist? If so, we're done...
if (isset($_classes[$class]))
{
return $_classes[$class];//如果已经保存在这里，就返回它
}
$name = FALSE;
// Look for the class first in the local application/libraries folder
// then in the native system/libraries folder
//这里，如果应用目录下有和系统目录下相同的类的话，优先引入应用目录，也就是你自己定义的。
foreach (array(APPPATH, BASEPATH) as $path)//Array ( [0] => application/ [1] => F:/products/zh.ci/system/ )
{
//在application 和system下面找要加载的类
if (file_exists($path.$directory.'/'.$class.'.php'))//
{
$name = $prefix.$class;
if (class_exists($name) === FALSE)
{
require($path.$directory.'/'.$class.'.php');
}
break;
}
}
//这里就用到的前缀扩展，如果在应用目录相应的目录下，有自己写的一些对CI库的扩展，那么我们加载的是它，而不是
//原来的。因为我们写的扩展是继承了CI原来的。
//所以可以看出，即使是CI的核心组件（core/下面的）我们都可以为之进行扩展。
// Is the request a class extension? If so we load it too
if (file_exists(APPPATH.$directory.'/'.config_item('subclass_prefix').$class.'.php'))
{
$name = config_item('subclass_prefix').$class;
if (class_exists($name) === FALSE)
{
require(APPPATH.$directory.'/'.config_item('subclass_prefix').$class.'.php');
}
}
// Did we find the class?
if ($name === FALSE) //没有找到对应的类
{
// Note: We use exit() rather then show_error() in order to avoid a
// self-referencing loop with the Excptions class
exit('Unable to locate the specified class: '.$class.'.php');
}
// Keep track of what we just loaded
//这个函数只是用来记录已经被加载过的类的类名而已
is_loaded($class);
$_classes[$class] = new $name();
return $_classes[$class];
}
}
// --------------------------------------------------------------------
/**
* Keeps track of which libraries have been loaded. This function is
* called by the load_class() function above
*
* @access public
* @return array
* //记录有哪些类是已经被加载的。
*/
if ( ! function_exists('is_loaded'))//记录加载过的类
{
function &is_loaded($class = '')
{
static $_is_loaded = array();
if ($class != '')
{
$_is_loaded[strtolower($class)] = $class;
}
return $_is_loaded;
}
}
// ------------------------------------------------------------------------
/**
* Loads the main config.php file
*
* This function lets us grab the config file even if the Config class
* hasn't been instantiated yet
*
* @access private
* @return array
*/
if ( ! function_exists('get_config'))//加载配置文件 同时也可以动态的替换配置文件中的配置
{
//这个$replace参数，是提供一个临时替换配置信息的机会，仅一次，因为执行一次后，配置信息都会保存在静态变量$_config中，不能
//改变
function &get_config($replace = array())
{
static $_config;
if (isset($_config))
{
return $_config[0];
}
// Is the config file in the environment folder?
if ( ! defined('ENVIRONMENT') OR ! file_exists($file_path = APPPATH.'config/'.ENVIRONMENT.'/config.php'))
{
$file_path = APPPATH.'config/config.php';
}
// Fetch the config file
if ( ! file_exists($file_path))
{
exit('The configuration file does not exist.');
}
require($file_path);
// Does the $config array exist in the file?
if ( ! isset($config) OR ! is_array($config))
{
exit('Your config file does not appear to be formatted correctly.');
}
// Are any values being dynamically replaced?
if (count($replace) > 0)//动态的替换配置文件
{
foreach ($replace as $key => $val)
{
if (isset($config[$key]))
{
$config[$key] = $val;
}
}
}
return $_config[0] =& $config;
}
}
// ------------------------------------------------------------------------
/**
* Returns the specified config item
*
* @access public
* //取得配置数组中某个元素。
* @return mixed
*/
if ( ! function_exists('config_item'))
{
function config_item($item)//根据$item返回配置文件中的某一项
{
static $_config_item = array();
if ( ! isset($_config_item[$item]))
{
$config =& get_config();
if ( ! isset($config[$item]))
{
return FALSE;
}
$_config_item[$item] = $config[$item];
}
return $_config_item[$item];
}
}
// ------------------------------------------------------------------------
/**
* Error Handler
*
* This function lets us invoke the exception class and
* display errors using the standard error template located
* in application/errors/errors.php
* This function will send the error page directly to the
* browser and exit.
*
* @access public
* @return void
*/
if ( ! function_exists('show_error'))//调用异常类
{
function show_error($message, $status_code = 500, $heading = 'An Error Was Encountered')
{
$_error =& load_class('Exceptions', 'core');
echo $_error->show_error($heading, $message, 'error_general', $status_code);
exit;
}
}
//show_error("Testing", $status_code = 500, $heading = 'An Error Was Encountered');
// ------------------------------------------------------------------------
/**
* 404 Page Handler
*
* This function is similar to the show_error() function above
* However, instead of the standard error template it displays
* 404 errors.
*
* @access public
* @return void
*/
if ( ! function_exists('show_404'))
{
function show_404($page = '', $log_error = TRUE)
{
$_error =& load_class('Exceptions', 'core');
$_error->show_404($page, $log_error);
exit;
}
}
// ------------------------------------------------------------------------
/**
* Error Logging Interface
*
* We use this as a simple mechanism to access the logging
* class and send messages to be logged.
*
* @access public
* @return void
*/
if ( ! function_exists('log_message'))//日志记录
{
function log_message($level = 'error', $message, $php_error = FALSE)
{
static $_log;
if (config_item('log_threshold') == 0)//是否记录日志
{
return;
}
$_log =& load_class('Log');
$_log->write_log($level, $message, $php_error);
}
}
// ------------------------------------------------------------------------
/**
* Set HTTP Status Header
*
* @access public
* @param int the status code
* @param string
* @return void
*/
//此函数构造一个响应头。$stati为响应码与其响应说明。
if ( ! function_exists('set_status_header'))
{
function set_status_header($code = 200, $text = '')//Http信息状态头
{
$stati = array(
200 => 'OK',
201 => 'Created',
202 => 'Accepted',
203 => 'Non-Authoritative Information',
204 => 'No Content',
205 => 'Reset Content',
206 => 'Partial Content',
300 => 'Multiple Choices',
301 => 'Moved Permanently',
302 => 'Found',
304 => 'Not Modified',
305 => 'Use Proxy',
307 => 'Temporary Redirect',
400 => 'Bad Request',
401 => 'Unauthorized',
403 => 'Forbidden',
404 => 'Not Found',
405 => 'Method Not Allowed',
406 => 'Not Acceptable',
407 => 'Proxy Authentication Required',
408 => 'Request Timeout',
409 => 'Conflict',
410 => 'Gone',
411 => 'Length Required',
412 => 'Precondition Failed',
413 => 'Request Entity Too Large',
414 => 'Request-URI Too Long',
415 => 'Unsupported Media Type',
416 => 'Requested Range Not Satisfiable',
417 => 'Expectation Failed',
500 => 'Internal Server Error',
501 => 'Not Implemented',
502 => 'Bad Gateway',
503 => 'Service Unavailable',
504 => 'Gateway Timeout',
505 => 'HTTP Version Not Supported'
);
if ($code == '' OR ! is_numeric($code))//$code不合法直接500错误
{
show_error('Status codes must be numeric', 500);
}
if (isset($stati[$code]) AND $text == '')
{
$text = $stati[$code];//获取代码对应的异常信息
}
if ($text == '')
{
show_error('No status text available. Please check your status code number or supply your own message text.', 500);
}
$server_protocol = (isset($_SERVER['SERVER_PROTOCOL'])) ? $_SERVER['SERVER_PROTOCOL'] : FALSE;//请求页面时通信协议的名称和版本。例如，“HTTP/1.0”。
if (substr(php_sapi_name(), 0, 3) == 'cgi')
{
header("Status: {$code} {$text}", TRUE);
}
elseif ($server_protocol == 'HTTP/1.1' OR $server_protocol == 'HTTP/1.0')
{
header($server_protocol." {$code} {$text}", TRUE, $code);
}
else
{
header("HTTP/1.1 {$code} {$text}", TRUE, $code);
}
}
}
// --------------------------------------------------------------------
/**
* Exception Handler 异常处理函数
*
* This is the custom exception handler that is declaired at the top
* of Codeigniter.php. The main reason we use this is to permit
* PHP errors to be logged in our own log files since the user may
* not have access to server logs. Since this function
* effectively intercepts PHP errors, however, we also need
* to display errors based on the current error_reporting level.
* We do that with the use of a PHP error template.
*
* @access private
* @return void
*/
if ( ! function_exists('_exception_handler'))
{
function _exception_handler($severity, $message, $filepath, $line)
{
// We don't bother with "strict" notices since they tend to fill up
// the log file with excess information that isn't normally very helpful.
// For example, if you are running PHP 5 and you use version 4 style
// class functions (without prefixes like "public", "private", etc.)
// you'll get notices telling you that these have been deprecated.
if ($severity == E_STRICT)
{
return;
}
$_error =& load_class('Exceptions', 'core');//加载异常类
// Should we display the error? We'll get the current error_reporting
// level and add its bits with the severity bits to find out.
if (($severity & error_reporting()) == $severity)
{
$_error->show_php_error($severity, $message, $filepath, $line);
}
// Should we log the error? No? We're done...
if (config_item('log_threshold') == 0)
{
return;
}
$_error->log_exception($severity, $message, $filepath, $line);
}
}
// --------------------------------------------------------------------
/**
* Remove Invisible Characters
*
* This prevents sandwiching null characters
* between ascii characters, like Java\0script.
*
* @access public
* @param string
* @return string
*/
if ( ! function_exists('remove_invisible_characters'))
{
function remove_invisible_characters($str, $url_encoded = TRUE)
{
$non_displayables = array();
// every control character except newline (dec 10)
// carriage return (dec 13), and horizontal tab (dec 09)
if ($url_encoded)
{
$non_displayables[] = '/%0[0-8bcef]/'; // url encoded 00-08, 11, 12, 14, 15
$non_displayables[] = '/%1[0-9a-f]/'; // url encoded 16-31
}
$non_displayables[] = '/[\x00-\x08\x0B\x0C\x0E-\x1F\x7F]+/S'; // 00-08, 11, 12, 14-31, 127
do
{
$str = preg_replace($non_displayables, '', $str, -1, $count);
}
while ($count);
return $str;
}
}
// ------------------------------------------------------------------------
/**
* Returns HTML escaped variable
*
* @access public
* @param mixed
* @return mixed
*/
if ( ! function_exists('html_escape'))
{
function html_escape($var)
{
if (is_array($var))
{
return array_map('html_escape', $var);//将回调函数作用到给定数组的单元上
}
else
{
return htmlspecialchars($var, ENT_QUOTES, config_item('charset'));
}
}
}
/* End of file Common.php */
/* Location: ./system/core/Common.php */
/**
* CodeIgniter
*
* An open source application development framework for PHP 5.1.6 or newer
*
* @package CodeIgniter
* @author ExpressionEngine Dev Team
* @copyright Copyright (c) 2008 - 2011, EllisLab, Inc.
* @license http://codeigniter.com/user_guide/license.html
* @link http://codeigniter.com
* @since Version 1.0
* @filesource
*/
// ------------------------------------------------------------------------
/**
* Common Functions
*
* Loads the base classes and executes the request.
*
* @package CodeIgniter
* @subpackage codeigniter
* @category Common Functions
* @author ExpressionEngine Dev Team
* @link http://codeigniter.com/user_guide/
*/
// ------------------------------------------------------------------------
/**
* Determines if the current version of PHP is greater then the supplied value
*
* Since there are a few places where we conditionally test for PHP > 5
* we'll set a static variable.
*
* @access public
* @param string
* @return bool TRUE if the current version is $version or higher
*/
if ( ! function_exists('is_php'))//判断当前php版本是否高于支持的版本
{
function is_php($version = '5.0.0')
{
static $_is_php;
$version = (string)$version;
if ( ! isset($_is_php[$version]))
{
// version_compare :Compares two "PHP-standardized" version number strings
$_is_php[$version] = (version_compare(PHP_VERSION, $version) < 0) ? FALSE : TRUE;
}
return $_is_php[$version];
}
}
// ------------------------------------------------------------------------
/**
* Tests for file writability
*
* is_writable() returns TRUE on Windows servers when you really can't write to
* the file, based on the read-only attribute. is_writable() is also unreliable
* on Unix servers if safe_mode is on.
*
* @access private
* @return void
*/
if ( ! function_exists('is_really_writable'))
{
function is_really_writable($file)
{
//DIRECTORY_SEPARATOR是系统的目录分割符。利用它的值可以知道当前是不是linux系统
// If we're on a Unix server with safe_mode off we call is_writable
if (DIRECTORY_SEPARATOR == '/' AND @ini_get("safe_mode") == FALSE)//
{
//如果是linux系统的话，那么可以直接调用此方法来判断文件是否可写
return is_writable($file);
}
// For windows servers and safe_mode "on" installations we'll actually
// write a file then read it. Bah...
//如果是windows系统，则尝试写入一个文件来判断。
if (is_dir($file))
{
//如果是目录，则创建一个随机命名的文件
$file = rtrim($file, '/').'/'.md5(mt_rand(1,100).mt_rand(1,100));
//如果文件不能创建，则返回不可写。
if (($fp = @fopen($file, FOPEN_WRITE_CREATE)) === FALSE)
{
return FALSE;
}
fclose($fp);
@chmod($file, DIR_WRITE_MODE);
@unlink($file);//删除刚才的文件
return TRUE;
}
elseif ( ! is_file($file) OR ($fp = @fopen($file, FOPEN_WRITE_CREATE)) === FALSE)
{
return FALSE;//如果是一个文件，而通过写入方式打不开，则返回不可写
}
fclose($fp);
return TRUE;
}
}
// ------------------------------------------------------------------------
/**
* 为什么还要定义这些全局函数呢？比如说，下面有很多函数，如get_config()、config_item()这两个方法不是应该由
* core/Config.php这个组件去做么？那个load_class()不应该由core/Loader.php去做么？ 把这些函数定义出来貌似
* 感觉架构变得不那么优雅，有点多余。
* 其实是出于这样一种情况：
* 比如说，如果一切和配置有关的动作都由Config组件来完成，一切加载的动作都由Loader来完成，
* 试想一下，如果我要加载Config组件，那么，必须得通过Loader来加载，所以Loader必须比Config要更早实例化，
* 但是如果Loader实例化的时候需要一些和Loader有关的配置信息才能实例化呢？那就必须通过Config来为它取得配置信息。
* 这里就出现了鸡和鸡蛋的问题。。
* 我之前写自己的框架也纠结过这样的问题，后来参考了YII框架，发现它里面其实都有同样的问题，它里面有个Exception的组件，
* 但是在加载这个Exception组件之前，在加载其它组件的时候，如果出错了，那谁来处理异常和错误信息呢？答案就是先定义一些公共的函数。
* 所以这些公共函数就很好地解决了这个问题，这也是为什么Common.php要很早被引入。
*
*/
/**
* Class registry
*
* This function acts as a singleton. If the requested class does not
* exist it is instantiated and set to a static variable. If it has
* previously been instantiated the variable is returned.
*
* @access public
* @param string the class name being requested
* @param string the directory where the class should be found
* @param string the class name prefix
* @return object
*
*/
if ( ! function_exists('load_class'))//CI的类的单例模式的加载
{
//加载类。默认是加载libraries里面的，如果要加载核心组件，$directory就为'core'
function &load_class($class, $directory = 'libraries', $prefix = 'CI_')
{
static $_classes = array();//静态数组 //用一个静态数组，保存已经加载过的类的实例，防止多次实例消耗资源，实现单例化。
// Does the class exist? If so, we're done...
if (isset($_classes[$class]))
{
return $_classes[$class];//如果已经保存在这里，就返回它
}
$name = FALSE;
// Look for the class first in the local application/libraries folder
// then in the native system/libraries folder
//这里，如果应用目录下有和系统目录下相同的类的话，优先引入应用目录，也就是你自己定义的。
foreach (array(APPPATH, BASEPATH) as $path)//Array ( [0] => application/ [1] => F:/products/zh.ci/system/ )
{
//在application 和system下面找要加载的类
if (file_exists($path.$directory.'/'.$class.'.php'))//
{
$name = $prefix.$class;
if (class_exists($name) === FALSE)
{
require($path.$directory.'/'.$class.'.php');
}
break;
}
}
//这里就用到的前缀扩展，如果在应用目录相应的目录下，有自己写的一些对CI库的扩展，那么我们加载的是它，而不是
//原来的。因为我们写的扩展是继承了CI原来的。
//所以可以看出，即使是CI的核心组件（core/下面的）我们都可以为之进行扩展。
// Is the request a class extension? If so we load it too
if (file_exists(APPPATH.$directory.'/'.config_item('subclass_prefix').$class.'.php'))
{
$name = config_item('subclass_prefix').$class;
if (class_exists($name) === FALSE)
{
require(APPPATH.$directory.'/'.config_item('subclass_prefix').$class.'.php');
}
}
// Did we find the class?
if ($name === FALSE) //没有找到对应的类
{
// Note: We use exit() rather then show_error() in order to avoid a
// self-referencing loop with the Excptions class
exit('Unable to locate the specified class: '.$class.'.php');
}
// Keep track of what we just loaded
//这个函数只是用来记录已经被加载过的类的类名而已
is_loaded($class);
$_classes[$class] = new $name();
return $_classes[$class];
}
}
// --------------------------------------------------------------------
/**
* Keeps track of which libraries have been loaded. This function is
* called by the load_class() function above
*
* @access public
* @return array
* //记录有哪些类是已经被加载的。
*/
if ( ! function_exists('is_loaded'))//记录加载过的类
{
function &is_loaded($class = '')
{
static $_is_loaded = array();
if ($class != '')
{
$_is_loaded[strtolower($class)] = $class;
}
return $_is_loaded;
}
}
// ------------------------------------------------------------------------
/**
* Loads the main config.php file
*
* This function lets us grab the config file even if the Config class
* hasn't been instantiated yet
*
* @access private
* @return array
*/
if ( ! function_exists('get_config'))//加载配置文件 同时也可以动态的替换配置文件中的配置
{
//这个$replace参数，是提供一个临时替换配置信息的机会，仅一次，因为执行一次后，配置信息都会保存在静态变量$_config中，不能
//改变
function &get_config($replace = array())
{
static $_config;
if (isset($_config))
{
return $_config[0];
}
// Is the config file in the environment folder?
if ( ! defined('ENVIRONMENT') OR ! file_exists($file_path = APPPATH.'config/'.ENVIRONMENT.'/config.php'))
{
$file_path = APPPATH.'config/config.php';
}
// Fetch the config file
if ( ! file_exists($file_path))
{
exit('The configuration file does not exist.');
}
require($file_path);
// Does the $config array exist in the file?
if ( ! isset($config) OR ! is_array($config))
{
exit('Your config file does not appear to be formatted correctly.');
}
// Are any values being dynamically replaced?
if (count($replace) > 0)//动态的替换配置文件
{
foreach ($replace as $key => $val)
{
if (isset($config[$key]))
{
$config[$key] = $val;
}
}
}
return $_config[0] =& $config;
}
}
// ------------------------------------------------------------------------
/**
* Returns the specified config item
*
* @access public
* //取得配置数组中某个元素。
* @return mixed
*/
if ( ! function_exists('config_item'))
{
function config_item($item)//根据$item返回配置文件中的某一项
{
static $_config_item = array();
if ( ! isset($_config_item[$item]))
{
$config =& get_config();
if ( ! isset($config[$item]))
{
return FALSE;
}
$_config_item[$item] = $config[$item];
}
return $_config_item[$item];
}
}
// ------------------------------------------------------------------------
/**
* Error Handler
*
* This function lets us invoke the exception class and
* display errors using the standard error template located
* in application/errors/errors.php
* This function will send the error page directly to the
* browser and exit.
*
* @access public
* @return void
*/
if ( ! function_exists('show_error'))//调用异常类
{
function show_error($message, $status_code = 500, $heading = 'An Error Was Encountered')
{
$_error =& load_class('Exceptions', 'core');
echo $_error->show_error($heading, $message, 'error_general', $status_code);
exit;
}
}
//show_error("Testing", $status_code = 500, $heading = 'An Error Was Encountered');
// ------------------------------------------------------------------------
/**
* 404 Page Handler
*
* This function is similar to the show_error() function above
* However, instead of the standard error template it displays
* 404 errors.
*
* @access public
* @return void
*/
if ( ! function_exists('show_404'))
{
function show_404($page = '', $log_error = TRUE)
{
$_error =& load_class('Exceptions', 'core');
$_error->show_404($page, $log_error);
exit;
}
}
// ------------------------------------------------------------------------
/**
* Error Logging Interface
*
* We use this as a simple mechanism to access the logging
* class and send messages to be logged.
*
* @access public
* @return void
*/
if ( ! function_exists('log_message'))//日志记录
{
function log_message($level = 'error', $message, $php_error = FALSE)
{
static $_log;
if (config_item('log_threshold') == 0)//是否记录日志
{
return;
}
$_log =& load_class('Log');
$_log->write_log($level, $message, $php_error);
}
}
// ------------------------------------------------------------------------
/**
* Set HTTP Status Header
*
* @access public
* @param int the status code
* @param string
* @return void
*/
//此函数构造一个响应头。$stati为响应码与其响应说明。
if ( ! function_exists('set_status_header'))
{
function set_status_header($code = 200, $text = '')//Http信息状态头
{
$stati = array(
200 => 'OK',
201 => 'Created',
202 => 'Accepted',
203 => 'Non-Authoritative Information',
204 => 'No Content',
205 => 'Reset Content',
206 => 'Partial Content',
300 => 'Multiple Choices',
301 => 'Moved Permanently',
302 => 'Found',
304 => 'Not Modified',
305 => 'Use Proxy',
307 => 'Temporary Redirect',
400 => 'Bad Request',
401 => 'Unauthorized',
403 => 'Forbidden',
404 => 'Not Found',
405 => 'Method Not Allowed',
406 => 'Not Acceptable',
407 => 'Proxy Authentication Required',
408 => 'Request Timeout',
409 => 'Conflict',
410 => 'Gone',
411 => 'Length Required',
412 => 'Precondition Failed',
413 => 'Request Entity Too Large',
414 => 'Request-URI Too Long',
415 => 'Unsupported Media Type',
416 => 'Requested Range Not Satisfiable',
417 => 'Expectation Failed',
500 => 'Internal Server Error',
501 => 'Not Implemented',
502 => 'Bad Gateway',
503 => 'Service Unavailable',
504 => 'Gateway Timeout',
505 => 'HTTP Version Not Supported'
);
if ($code == '' OR ! is_numeric($code))//$code不合法直接500错误
{
show_error('Status codes must be numeric', 500);
}
if (isset($stati[$code]) AND $text == '')
{
$text = $stati[$code];//获取代码对应的异常信息
}
if ($text == '')
{
show_error('No status text available. Please check your status code number or supply your own message text.', 500);
}
$server_protocol = (isset($_SERVER['SERVER_PROTOCOL'])) ? $_SERVER['SERVER_PROTOCOL'] : FALSE;//请求页面时通信协议的名称和版本。例如，“HTTP/1.0”。
if (substr(php_sapi_name(), 0, 3) == 'cgi')
{
header("Status: {$code} {$text}", TRUE);
}
elseif ($server_protocol == 'HTTP/1.1' OR $server_protocol == 'HTTP/1.0')
{
header($server_protocol." {$code} {$text}", TRUE, $code);
}
else
{
header("HTTP/1.1 {$code} {$text}", TRUE, $code);
}
}
}
// --------------------------------------------------------------------
/**
* Exception Handler 异常处理函数
*
* This is the custom exception handler that is declaired at the top
* of Codeigniter.php. The main reason we use this is to permit
* PHP errors to be logged in our own log files since the user may
* not have access to server logs. Since this function
* effectively intercepts PHP errors, however, we also need
* to display errors based on the current error_reporting level.
* We do that with the use of a PHP error template.
*
* @access private
* @return void
*/
if ( ! function_exists('_exception_handler'))
{
function _exception_handler($severity, $message, $filepath, $line)
{
// We don't bother with "strict" notices since they tend to fill up
// the log file with excess information that isn't normally very helpful.
// For example, if you are running PHP 5 and you use version 4 style
// class functions (without prefixes like "public", "private", etc.)
// you'll get notices telling you that these have been deprecated.
if ($severity == E_STRICT)
{
return;
}
$_error =& load_class('Exceptions', 'core');//加载异常类
// Should we display the error? We'll get the current error_reporting
// level and add its bits with the severity bits to find out.
if (($severity & error_reporting()) == $severity)
{
$_error->show_php_error($severity, $message, $filepath, $line);
}
// Should we log the error? No? We're done...
if (config_item('log_threshold') == 0)
{
return;
}
$_error->log_exception($severity, $message, $filepath, $line);
}
}
// --------------------------------------------------------------------
/**
* Remove Invisible Characters
*
* This prevents sandwiching null characters
* between ascii characters, like Java\0script.
*
* @access public
* @param string
* @return string
*/
if ( ! function_exists('remove_invisible_characters'))
{
function remove_invisible_characters($str, $url_encoded = TRUE)
{
$non_displayables = array();
// every control character except newline (dec 10)
// carriage return (dec 13), and horizontal tab (dec 09)
if ($url_encoded)
{
$non_displayables[] = '/%0[0-8bcef]/'; // url encoded 00-08, 11, 12, 14, 15
$non_displayables[] = '/%1[0-9a-f]/'; // url encoded 16-31
}
$non_displayables[] = '/[\x00-\x08\x0B\x0C\x0E-\x1F\x7F]+/S'; // 00-08, 11, 12, 14-31, 127
do
{
$str = preg_replace($non_displayables, '', $str, -1, $count);
}
while ($count);
return $str;
}
}
// ------------------------------------------------------------------------
/**
* Returns HTML escaped variable
*
* @access public
* @param mixed
* @return mixed
*/
if ( ! function_exists('html_escape'))
{
function html_escape($var)
{
if (is_array($var))
{
return array_map('html_escape', $var);//将回调函数作用到给定数组的单元上
}
else
{
return htmlspecialchars($var, ENT_QUOTES, config_item('charset'));
}
}
}
/* End of file Common.php */
/* Location: ./system/core/Common.php */
