Issue 6559 - Convert subscriptions property of Filter to a set

lib/filterListener.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present 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 124 matching lines @@
  * if necessary.
  * @param {Filter} filter filter that has been added
  */
 function addFilter(filter)
 {
   if (!(filter instanceof ActiveFilter) || filter.disabled)
     return;
 
   let hasEnabled = false;
   let allowSnippets = false;
-  for (let i = 0; i < filter.subscriptions.length; i++)
+  for (let subscription of filter.subscriptions)
   {
-    let subscription = filter.subscriptions[i];
-
     if (!subscription.disabled)
     {
       hasEnabled = true;
 
       // Allow snippets to be executed only by the circumvention lists or the
       // user's own filters.
       if (subscription.type == "circumvention" ||
           subscription instanceof SpecialSubscription)
       {
         allowSnippets = true;
@@ skipping 23 matching lines @@
  * @param {Filter} filter filter that has been removed
  */
 function removeFilter(filter)
 {
   if (!(filter instanceof ActiveFilter))
     return;
 
   if (!filter.disabled)
   {
     let hasEnabled = false;
-    for (let i = 0; i < filter.subscriptions.length; i++)
+    for (let subscription of filter.subscriptions)
     {
-      if (!filter.subscriptions[i].disabled)
+      if (!subscription.disabled)
       {
         hasEnabled = true;
         break;
       }
     }
     if (hasEnabled)
       return;
   }
 
   if (filter instanceof RegExpFilter)
@@ skipping 131 matching lines @@
   {
     if (!subscription.disabled)
       addFilters(subscription.filters);
   }
 }
 
 function onSave()
 {
   isDirty = 0;
 }