CI framework source code reading---------hook class hooks.php_PHP tutorial

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/** 

 * 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 

 */  

  

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

  

/**

* CodeIgniter Hooks Class

*

* Provides a mechanism to extend the base system without hacking.

* User manual address: http://codeigniter.org.cn/user_guide/general/hooks.html

* @package CodeIgniter

* @subpackage Libraries

* @category Libraries

* @author ExpressionEngine Dev Team

* @link http://codeigniter.com/user_guide/libraries/encryption.html

*/  

class CI_Hooks {  

  

    /**

* Determines wether hooks are enabled

* Determine whether the hook is enabled

*

* @var bool

*/  

    var $enabled        = FALSE;  

    /** 

     * List of all hooks set in config/hooks.php 

     * 

     * @var array 

     */  

    var $hooks          = array();  

    /** 

     * Determines wether hook is in progress, used to prevent 防止 infinte 无限 loops 

     * 

     * @var bool 

     */  

    var $in_progress    = FALSE;  

  

    /** 

     * Constructor 

     * 

     */  

    function __construct()  

    {  

        $this->_initialize();  

        log_message('debug', "Hooks Class Initialized");  

    }  

  

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

  

    /**

* Initialize the Hooks Preferences parameters, preferences

* Initialization hook

* @access private

* @return void

*/  

    function _initialize()  

    {  

        $CFG =& load_class('Config', 'core');  

  

        // If hooks are not enabled in the config file  

        // there is nothing else to do  

        // 如果配置文件中设置了是不允许hooks，则直接返回退出本函数。  

        if ($CFG->item('enable_hooks') == FALSE)  

        {  

            return;  

        }  

  

        // Grab the "hooks" definition file.  

        // 抓取钩子的定义文件  

        // If there are no hooks, we're done.  

// If hooks.php is not defined and the $hook array is not defined, we will return directly

if (defined('ENVIRONMENT') AND is_file(APPPATH.'config/'.ENVIRONMENT.'/hooks.php'))

{

include(APPPATH.'config/'.ENVIRONMENT.'/hooks.php');

} }

elseif (is_file(APPPATH.'config/hooks.php'))

{

include(APPPATH.'config/hooks.php');

} }

if ( ! isset($hook) OR ! is_array($hook))

{

return;

} }

// Reference the $hook array in hooks.php to $this->hooks

// Enable $this->enabled

$this->hooks =& $hook;

$this->enabled = TRUE;

}

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

/**

* Call Hook

* Externally, the _call_hook function is actually called to call the hook program.

* In this method, _run_hook is called to execute the corresponding hook.

* Calls a particular hook

*

* @access private

* @param string the hook name

* @return mixed

*/

function _call_hook($which = '')

{

// Determine whether $this->enabled is turned on and whether the hook to be called exists in $htis->hooks.

if ( ! $this->enabled OR ! isset($this->hooks[$which]))

{

return FALSE;

} }

// Determine whether the hook to be called is a two-dimensional array, and if so, traverse and execute it.

// If it is not a two-dimensional array, execute it directly

// It is explained here that multiple hooks can be executed at one hook point, which is achieved by defining a two-dimensional array.

if (isset($this->hooks[$which][0]) AND is_array($this->hooks[$which][0]))

{

foreach ($this->hooks[$which] as $val)

                                                                 

$this->_run_hook($val);

      }  

} }

else

{

$this->_run_hook($this->hooks[$which]);

} }

return TRUE;

}

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

/**

* Run Hook

* Run the hook

* Runs a particular hook

*

* @access private

* @param array the hook details

* @return bool

*/

function _run_hook($data)

{

/*

* $data is the hook array we defined in APPPATH/config/hook.php

* $hook['pre_controller'] = array(

                                                                             

                                                                                 

                                                                                                                         

                                                                                                                     

                                                                                                                                         

* * );

* *

* Since each hook must be composed of an array

* So here we judge whether $data is an array and if not, return

* *

*/

if ( ! is_array($data))

{

return FALSE;

} }

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

// Safety - Prevents run-away loops

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

// If the script being called happens to have the same

// hook call within it a loop can happen

// If a hook is called and certain scripts are executed, other hooks may be triggered in these scripts

// If this other hook contains the current

// hook, then it will enter an infinite loop. The existence of in_progress is to prevent this situation.

if ($this->in_progress == TRUE)

{

return;

} }

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

// Take out the data in data and load APPPATH.$data['filepath'].$data['filename'];

// Set file path

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

if ( ! isset($data['filepath']) OR ! isset($data['filename']))

{

return FALSE;

} }

$filepath = APPPATH.$data['filepath'].'/'.$data['filename'];

if ( ! file_exists($filepath))

{

return FALSE;

} }

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

// Set class/function name

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

$class = FALSE;

$function = FALSE;

$params = '';

// Take out the class function params in $hooks

if (isset($data['class']) AND $data['class'] != '')

{

$class = $data['class'];

} }

if (isset($data['function']))

{

$function = $data['function'];

} }

if (isset($data['params']))

{

$params = $data['params'];

} }

if ($class === FALSE AND $function === FALSE)

{

return FALSE;

} }

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

// Set the in_progress flag

// Before starting to execute the corresponding program of the hook, first set the status of the current hook to running.

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

$this->in_progress = TRUE;

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

// Call the requested class and/or function

// Contain hook file and instantiate class, call function

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

if ($class !== FALSE)

{

if ( ! class_exists($class))

                                                                 

require($filepath);

      }  

$HOOK = new $class;

$HOOK->$function($params);

} }

else

{

if ( ! function_exists($function))

                                                                 

require($filepath);

      }  

$function($params);

} } www.2cto.com

// After executing the corresponding program, change the status of the current hook to non-running again

// So that it can be triggered again.

$this->in_progress = FALSE;

return TRUE;

}

}

// END CI_Hooks class

/* End of file Hooks.php */

/* Location: ./system/core/Hooks.php */

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