Issue 3870 - Rewrite legacy options page to use async messages

options.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 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
@@ skipping 65 matching lines @@
                                "text", "removeExisting");
 var addFilter = wrapper({type: "filters.add"}, "text");
 var getFilters = wrapper({type: "filters.get"}, "subscriptionUrl");
 var removeFilter = wrapper({type: "filters.remove"}, "text");
 
 var i18n = ext.i18n;
 var whitelistedDomainRegexp = /^@@\|\|([^\/:]+)\^\$document$/;
 var delayedSubscriptionSelection = null;
 
 var acceptableAdsUrl;
-getPref("subscriptions_exceptionsurl", function(url)
-{
-  acceptableAdsUrl = url;
-});
 
 // Loads options and sets UI elements accordingly
 function loadOptions()
 {
   // Set page title to i18n version of "Adblock Plus Options"
   document.title = i18n.getMessage("options");
 
   // Set links
-  $("#acceptableAdsLink").attr("href", acceptableAdsUrl);

[Sebastian Noack, 2016/04/07 13:15:51]

We have a race here. Dependent on whether we first get a response with the
Acceptable Ads URL, or whether the DOM is completed first the URL might be set
correctly or not.

If you simply move getPref("subscriptions_exceptionsurl", ..) here, and this
line into it's callback, you would eliminate that race condition.

[kzar, 2016/04/07 13:28:15]

Done.

+  getPref("subscriptions_exceptionsurl", function(url)
+  {
+    acceptableAdsUrl = url;
+    $("#acceptableAdsLink").attr("href", acceptableAdsUrl);
+  });
   getDocLink("acceptable_ads", function(url)
   {
     $("#acceptableAdsDocs").attr("href", url);
   });
   getDocLink("filterdoc", function(url)
   {
     setLinks("filter-must-follow-syntax", url);
   });
   getInfo("application", function(application)
   {
@@ skipping 632 matching lines @@
       onFilterMessage(message.action, message.args[0]);
       break;
     case "prefs.respond":
       onPrefMessage(message.action, message.args[0]);
       break;
     case "subscriptions.respond":
       onSubscriptionMessage(message.action, message.args[0]);
       break;
   }
 });