The Tor Browser / file revision

 /* This Source Code Form is subject to the terms of the Mozilla Public

  * License, v. 2.0. If a copy of the MPL was not distributed with this

  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

 "use strict";

 this.EXPORTED_SYMBOLS = [ "Feeds" ];

 Components.utils.import("resource://gre/modules/XPCOMUtils.jsm");

 XPCOMUtils.defineLazyModuleGetter(this, "BrowserUtils",

                                   "resource://gre/modules/BrowserUtils.jsm");

 const Ci = Components.interfaces;

 this.Feeds = {

   /**

    * isValidFeed: checks whether the given data represents a valid feed.

    *

    * @param  aLink

    *         An object representing a feed with title, href and type.

    * @param  aPrincipal

    *         The principal of the document, used for security check.

    * @param  aIsFeed

    *         Whether this is already a known feed or not, if true only a security

    *         check will be performed.

    */

   isValidFeed: function(aLink, aPrincipal, aIsFeed) {

     if (!aLink || !aPrincipal)

       return false;

     var type = aLink.type.toLowerCase().replace(/^\s+|\s*(?:;.*)?$/g, "");

     if (!aIsFeed) {

       aIsFeed = (type == "application/rss+xml" ||

                  type == "application/atom+xml");

     }

     if (aIsFeed) {

       try {

         BrowserUtils.urlSecurityCheck(aLink.href, aPrincipal,

                                       Ci.nsIScriptSecurityManager.DISALLOW_INHERIT_PRINCIPAL);

         return type || "application/rss+xml";

       }

       catch(ex) {

       }

     }

     return null;

   },

 };