Common.php

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<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 4.3.2 or newer
 *
 * @package             CodeIgniter
 * @author              ExpressionEngine Dev Team
 * @copyright   Copyright (c) 2008, 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/
 */

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

/**
 * 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
 */
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(rand(1,100));

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

                fclose($fp);
                @chmod($file, DIR_WRITE_MODE);
                @unlink($file);
                return TRUE;
        }
        elseif (($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        bool    optional flag that lets classes get loaded but not instantiated
* @return       object
*/
function &load_class($class, $instantiate = TRUE)
{
        static $objects = array();

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

        // If the requested class does not exist in the application/libraries
        // folder we'll load the native class from the system/libraries folder. 
        if (file_exists(APPPATH.'libraries/'.config_item('subclass_prefix').$class.EXT))
        {
                require(BASEPATH.'libraries/'.$class.EXT);
                require(APPPATH.'libraries/'.config_item('subclass_prefix').$class.EXT);
                $is_subclass = TRUE;
        }
        else
        {
                if (file_exists(APPPATH.'libraries/'.$class.EXT))
                {
                        require(APPPATH.'libraries/'.$class.EXT);
                        $is_subclass = FALSE;
                }
                else
                {
                        require(BASEPATH.'libraries/'.$class.EXT);
                        $is_subclass = FALSE;
                }
        }

        if ($instantiate == FALSE)
        {
                $objects[$class] = TRUE;
                return $objects[$class];
        }

        if ($is_subclass == TRUE)
        {
                $name = config_item('subclass_prefix').$class;
                $objects[$class] =& new $name();
                return $objects[$class];
        }

        $name = ($class != 'Controller') ? 'CI_'.$class : $class;
        
        $objects[$class] =& new $name();
        return $objects[$class];
}

/**
* Loads the main config.php file
*
* @access       private
* @return       array
*/
function &get_config()
{
        static $main_conf;

        if ( ! isset($main_conf))
        {
                if ( ! file_exists(APPPATH.'config/config'.EXT))
                {
                        exit('The configuration file config'.EXT.' does not exist.');
                }

                require(APPPATH.'config/config'.EXT);

                if ( ! isset($config) OR ! is_array($config))
                {
                        exit('Your config file does not appear to be formatted correctly.');
                }

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

/**
* Gets a config item
*
* @access       public
* @return       mixed
*/
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
*/
function show_error($message)
{
        $error =& load_class('Exceptions');
        echo $error->show_error('An Error Was Encountered', $message);
        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
*/
function show_404($page = '')
{
        $error =& load_class('Exceptions');
        $error->show_404($page);
        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
*/
function log_message($level = 'error', $message, $php_error = FALSE)
{
        static $LOG;
        
        $config =& get_config();
        if ($config['log_threshold'] == 0)
        {
                return;
        }

        $LOG =& load_class('Log');
        $LOG->write_log($level, $message, $php_error);
}

/**
* Exception Handler
*
* This is the custom exception handler that is declaired at the top
* of Codeigniter.php.  The main reason we use this is permit
* PHP errors to be logged in our own log files since we 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
*/
function _exception_handler($severity, $message, $filepath, $line)
{       
         // We don't bother with "strict" notices since they will fill up
         // the log file with 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');

        // 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...
        $config =& get_config();
        if ($config['log_threshold'] == 0)
        {
                return;
        }

        $error->log_exception($severity, $message, $filepath, $line);
}



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