<?php
  /**
   * Copyright 2010-2013 Amazon.com, Inc. or its affiliates. All Rights Reserved.
   *
   * Licensed under the Apache License, Version 2.0 (the "License").
   * You may not use this file except in compliance with the License.
   * A copy of the License is located at
   *
   * http://aws.amazon.com/apache2.0
   *
   * or in the "license" file accompanying this file. This file is distributed
   * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
   * express or implied. See the License for the specific language governing
   * permissions and limitations under the License.
   */
  
  namespace Aws\S3;
  
  use Aws\Common\Signature\SignatureInterface;
  use Aws\Common\Credentials\CredentialsInterface;
  use Guzzle\Http\Message\RequestInterface;
  
  /**
   * Amazon S3 signature interface
   * @link http://docs.amazonwebservices.com/AmazonS3/latest/dev/RESTAuthentication.html
   */
  interface S3SignatureInterface extends SignatureInterface
  {
      /**
       * Sign a string for Amazon S3
       *
       * @param string               $string      String to sign
       * @param CredentialsInterface $credentials Credentials used to sign
       *
       * @return string
       */
      public function signString($string, CredentialsInterface $credentials);
  
      /**
       * Create a canonicalized string for a signature.
       *
       * @param RequestInterface $request Base on the request
       * @param string           $expires Pass a UNIX timestamp if creating a query signature
       *
       * @return string Returns a canonicalized string for an Amazon S3 signature.
       */
      public function createCanonicalizedString(RequestInterface $request, $expires = null);
  }