<?php

/**

 * Zend Framework

 *

 * LICENSE

 *

 * This source file is subject to the new BSD license that is bundled

 * with this package in the file LICENSE.txt.

 * It is also available through the world-wide-web at this URL:

 * http://framework.zend.com/license/new-bsd

 * If you did not receive a copy of the license and are unable to

 * obtain it through the world-wide-web, please send an email

 * to license@zend.com so we can send you a copy immediately.

 *

 * @category   Zend

 * @package    Zend_Auth

 * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)

 * @license    http://framework.zend.com/license/new-bsd     New BSD License

 * @version    $Id: Auth.php 20096 2010-01-06 02:05:09Z bkarwin $

 */

/**

 * @category   Zend

 * @package    Zend_Auth

 * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)

 * @license    http://framework.zend.com/license/new-bsd     New BSD License

 */

class Zend_Auth

{

    /**

     * Singleton instance

     *

     * @var Zend_Auth

     */

    protected static $_instance = null;

    /**

     * Persistent storage handler

     *

     * @var Zend_Auth_Storage_Interface

     */

    protected $_storage = null;

    /**

     * Singleton pattern implementation makes "new" unavailable

     *

     * @return void

     */

    protected function __construct()

    {}

    /**

     * Singleton pattern implementation makes "clone" unavailable

     *

     * @return void

     */

    protected function __clone()

    {}

    /**

     * Returns an instance of Zend_Auth

     *

     * Singleton pattern implementation

     *

     * @return Zend_Auth Provides a fluent interface

     */

    public static function getInstance()

    {

        if (null === self::$_instance) {

            self::$_instance = new self();

        }

        return self::$_instance;

    }

    /**

     * Returns the persistent storage handler

     *

     * Session storage is used by default unless a different storage adapter has been set.

     *

     * @return Zend_Auth_Storage_Interface

     */

    public function getStorage()

    {

        if (null === $this->_storage) {

            /**

             * @see Zend_Auth_Storage_Session

             */

            require_once 'Zend/Auth/Storage/Session.php';

            $this->setStorage(new Zend_Auth_Storage_Session());

        }

        return $this->_storage;

    }

    /**

     * Sets the persistent storage handler

     *

     * @param  Zend_Auth_Storage_Interface $storage

     * @return Zend_Auth Provides a fluent interface

     */

    public function setStorage(Zend_Auth_Storage_Interface $storage)

    {

        $this->_storage = $storage;

        return $this;

    }

    /**

     * Authenticates against the supplied adapter

     *

     * @param  Zend_Auth_Adapter_Interface $adapter

     * @return Zend_Auth_Result

     */

    public function authenticate(Zend_Auth_Adapter_Interface $adapter)

    {

        $result = $adapter->authenticate();

        /**

         * ZF-7546 - prevent multiple succesive calls from storing inconsistent results

         * Ensure storage has clean state

         */

        if ($this->hasIdentity()) {

            $this->clearIdentity();

        }

        if ($result->isValid()) {

            $this->getStorage()->write($result->getIdentity());

        }

        return $result;

    }

    /**

     * Returns true if and only if an identity is available from storage

     *

     * @return boolean

     */

    public function hasIdentity()

    {

        return !$this->getStorage()->isEmpty();

    }

    /**

     * Returns the identity from storage or null if no identity is available

     *

     * @return mixed|null

     */

    public function getIdentity()

    {

        $storage = $this->getStorage();

        if ($storage->isEmpty()) {

            return null;

        }

        return $storage->read();

    }

    /**

     * Clears the identity from persistent storage

     *

     * @return void

     */

    public function clearIdentity()

    {

        $this->getStorage()->clear();

    }

}