source: sourcecode/system/core/Common.php @ 1

<?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 $version or higher
*/
if ( ! function_exists('is_php'))
{
        function is_php($version = '5.0.0')
        {
                static $_is_php;
                $version = (string)$version;

                if ( ! isset($_is_php[$version]))
                {
                        $_is_php[$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($file)
        {
                // If we're on a Unix server with safe_mode off we call is_writable
                if (DIRECTORY_SEPARATOR == '/' AND @ini_get("safe_mode") == FALSE)
                {
                        return is_writable($file);
                }

                // For windows servers and safe_mode "on" installations we'll actually
                // write a file then read it.  Bah...
                if (is_dir($file))
                {
                        $file = rtrim($file, '/').'/'.md5(mt_rand(1,100).mt_rand(1,100));

                        if (($fp = @fopen($file, FOPEN_WRITE_CREATE)) === FALSE)
                        {
                                return FALSE;
                        }

                        fclose($fp);
                        @chmod($file, DIR_WRITE_MODE);
                        @unlink($file);
                        return TRUE;
                }
                elseif ( ! is_file($file) OR ($fp = @fopen($file, FOPEN_WRITE_CREATE)) === FALSE)
                {
                        return FALSE;
                }

                fclose($fp);
                return TRUE;
        }
}

// ------------------------------------------------------------------------

/**
* 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'))
{
        function &load_class($class, $directory = 'libraries', $prefix = 'CI_')
        {
                static $_classes = array();

                // Does the class exist?  If so, we're done...
                if (isset($_classes[$class]))
                {
                        return $_classes[$class];
                }

                $name = FALSE;

                // Look for the class first in the local application/libraries folder
                // then in the native system/libraries folder
                foreach (array(APPPATH, BASEPATH) as $path)
                {
                        if (file_exists($path.$directory.'/'.$class.'.php'))
                        {
                                $name = $prefix.$class;

                                if (class_exists($name) === FALSE)
                                {
                                        require($path.$directory.'/'.$class.'.php');
                                }

                                break;
                        }
                }

                // 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 ($name === FALSE)
                {
                        // Note: We use exit() rather then show_error() in order to avoid a
                        // self-referencing loop with the Excptions class
                        exit('Unable to locate the specified class: '.$class.'.php');
                }

                // Keep track of what we just loaded
                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
*/
if ( ! function_exists('is_loaded'))
{
        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'))
{
        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($replace) > 0)
                {
                        foreach ($replace as $key => $val)
                        {
                                if (isset($config[$key]))
                                {
                                        $config[$key] = $val;
                                }
                        }
                }

                return $_config[0] =& $config;
        }
}

// ------------------------------------------------------------------------

/**
* Returns the specified config item
*
* @access       public
* @return       mixed
*/
if ( ! function_exists('config_item'))
{
        function config_item($item)
        {
                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'))
{
        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;
        }
}

// ------------------------------------------------------------------------

/**
* 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'))
{
        function log_message($level = 'error', $message, $php_error = FALSE)
        {
                static $_log;

                if (config_item('log_threshold') == 0)
                {
                        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
 */
if ( ! function_exists('set_status_header'))
{
        function set_status_header($code = 200, $text = '')
        {
                $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))
                {
                        show_error('Status codes must be numeric', 500);
                }

                if (isset($stati[$code]) AND $text == '')
                {
                        $text = $stati[$code];
                }

                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;

                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
*
* 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');

                // 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', $var);
                }
                else
                {
                        return htmlspecialchars($var, ENT_QUOTES, config_item('charset'));
                }
        }
}

/* End of file Common.php */
/* Location: ./system/core/Common.php */