Bug 413915 - isValidFeed modifies its first paramter, r=sayrer

browser/base/content/browser.js

@@ -2825,9 +2825,8 @@ const DOMLinkHandler = {
             if (!rels.feed && rels.alternate && rels.stylesheet)
               break;
 
-            var feed = { title: link.title, href: link.href, type: link.type };
-            if (isValidFeed(feed, link.ownerDocument.nodePrincipal, rels.feed)) {
-              FeedHandler.addFeed(feed, link.ownerDocument);
+            if (isValidFeed(link, link.ownerDocument.nodePrincipal, rels.feed)) {
+              FeedHandler.addFeed(link, link.ownerDocument);
               feedAdded = true;
             }
           }

browser/base/content/pageinfo/feeds.js

@@ -62,9 +62,9 @@ function initFeedTab()
     }
 
     if (rels.feed || (link.type && rels.alternate && !rels.stylesheet)) {
-      var feed = { title: link.title, href: link.href, type: link.type || "" };
-      if (isValidFeed(feed, gDocument.nodePrincipal, rels.feed)) {
-        var type = feedTypes[feed.type] || feedTypes["application/rss+xml"];
+      var type = isValidFeed(link, gDocument.nodePrincipal, rels.feed);
+      if (type) {
+        type = feedTypes[type] || feedTypes["application/rss+xml"];
         addRow(feed.title, type, feed.href);
       }
     }

browser/base/content/utilityOverlay.js

@@ -631,7 +631,7 @@ function openNewWindowWith(aURL, aDocument, aPostData, aAllowThirdPartyFixup,
 /**
  * isValidFeed: checks whether the given data represents a valid feed.
  *
- * @param  aData
+ * @param  aLink
  *         An object representing a feed with title, href and type.
  * @param  aPrincipal
  *         The principal of the document, used for security check.
@@ -639,33 +639,28 @@ function openNewWindowWith(aURL, aDocument, aPostData, aAllowThirdPartyFixup,
  *         Whether this is already a known feed or not, if true only a security
  *         check will be performed.
  */ 
-function isValidFeed(aData, aPrincipal, aIsFeed)
+function isValidFeed(aLink, aPrincipal, aIsFeed)
 {
-  if (!aData || !aPrincipal)
+  if (!aLink || !aPrincipal)
     return false;
 
+  var type = aLink.type.toLowerCase().replace(/^\s+|\s*(?:;.*)?$/g, "");
   if (!aIsFeed) {
-    var type = aData.type && aData.type.toLowerCase();
-    type = type.replace(/^\s+|\s*(?:;.*)?$/g, "");
-
     aIsFeed = (type == "application/rss+xml" ||
                type == "application/atom+xml");
   }
 
   if (aIsFeed) {
     try {
-      urlSecurityCheck(aData.href, aPrincipal,
+      urlSecurityCheck(aLink.href, aPrincipal,
                        Components.interfaces.nsIScriptSecurityManager.DISALLOW_INHERIT_PRINCIPAL);
+      return type || "application/rss+xml";
     }
     catch(ex) {
-      aIsFeed = false;
     }
   }
 
-  if (type)
-    aData.type = type;
-
-  return aIsFeed;
+  return null;
 }
 
 // aCalledFromModal is optional