Refactored the abstraction layer to address prerendered pages on Safari caused by leaky abstraction

safari/ext/content.js

 /*
  * This file is part of Adblock Plus <http://adblockplus.org/>,
- * Copyright (C) 2006-2013 Eyeo GmbH
+ * Copyright (C) 2006-2014 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 (function()
 {
+  // the safari object is missing in frames created from javascript: URLs.
+  // So we have to fallback to the safari object from the parent frame.
+  if (!("safari" in window))
+    window.safari = window.parent.safari;
+
+
   /* Intialization */
 
   var beforeLoadEvent = document.createEvent("Event");
   beforeLoadEvent.initEvent("beforeload");
 
   var isTopLevel = window == window.top;
   var isPrerendered = document.visibilityState == "prerender";
 
   var documentInfo = safari.self.tab.canLoad(
     beforeLoadEvent,
@@ skipping 14 matching lines @@
       document.removeEventListener("visibilitychange", onVisibilitychange);
     };
     document.addEventListener("visibilitychange", onVisibilitychange);
   }
 
 
   /* Web requests */
 
   document.addEventListener("beforeload", function(event)
   {
+    // we don't block non-HTTP requests anyway, so we can bail out
+    // without asking the background page. This is even necessary
+    // because passing large data (like a photo encoded as data: URL)
+    // to the background page, freezes Safari.
+    if (!/^https?:/.test(event.url))
+      return;
+
     var type;
     switch(event.target.localName)
     {
       case "frame":
       case "iframe":
         type = "sub_frame";
         break;
       case "img":
         type = "image";
         break;
@@ skipping 19 matching lines @@
         category: "webRequest",
         url: event.url,
         type: type,
         pageId: documentInfo.pageId,
         frameId: documentInfo.frameId
       }
     ))
     {
       event.preventDefault();
 
-      // Safari doesn't dispatch an "error" or "load" event when preventing an
-      // element from loading by cancelling the "beforeload" event. So we have
-      // to dispatch it manually. Otherwise element collapsing wouldn't work.
-      var evt = document.createEvent("Event");
-      evt.initEvent(type == "sub_frame" ? "load" : "error");
-      event.target.dispatchEvent(evt);
+      // Safari doesn't dispatch an "error" event when preventing an element
+      // from loading by cancelling the "beforeload" event. So we have to
+      // dispatch it manually. Otherwise element collapsing wouldn't work.
+      if (type != "sub_frame")
+      {
+        var evt = document.createEvent("Event");
+        evt.initEvent("error");
+        event.target.dispatchEvent(evt);
+      }
     }
   }, true);
 
 
   /* Context menus */
 
   document.addEventListener("contextmenu", function(event)
   {
     var element = event.srcElement;
     safari.self.tab.setContextMenuEventUserInfo(event, {
@@ skipping 271 matching lines @@
             messageProxy.handleResponse(event.message);
             break;
           case "proxyCallback":
             backgroundPageProxy.handleCallback(event.message);
             break;
         }
       }
     }
   });
 })();