CodeIgniter框架钩子机制实现方法【hooks类】

<"Hooks Class Initialized");
  }

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

  /**
   * Initialize the Hooks Preferences
   *
   * @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

    if ($CFG->item('enable_hooks') == FALSE)
    {
      return;
    }

    // Grab the "hooks" definition file.
    // If there are no hooks, we're done.

    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;
    }

    $this->hooks =& $hook;
    $this->enabled = TRUE;
  }

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

  /**
   * Call Hook
   *
   * Calls a particular hook
   *
   * @access private
   * @param  string the hook name
   * @return mixed
   */
  function _call_hook($which = '')
  {
    if ( ! $this->enabled OR ! isset($this->hooks[$which]))
    {
      return FALSE;
    }

    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
   *
   * Runs a particular hook
   *
   * @access private
   * @param  array  the hook details
   * @return bool
   */
  function _run_hook($data)
  {
    if ( ! is_array($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 ($this->in_progress == TRUE)
    {
      return;
    }

    // -----------------------------------
    // 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    = '';

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

    $this->in_progress = TRUE;

    // -----------------------------------
    // Call the requested class and/or 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);
    }

    $this->in_progress = FALSE;
    return TRUE;
  }

}

// END CI_Hooks class

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