Issue 7178 - Remove filter order randomization

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 199 matching lines @@
       ElemHide.remove(filter);
     else if (filter instanceof ElemHideEmulationFilter)
       ElemHideEmulation.remove(filter);
     else
       ElemHideExceptions.remove(filter);
   }
   else if (filter instanceof SnippetFilter)
     Snippets.remove(filter);
 }
 
-const primes = [101, 109, 131, 149, 163, 179, 193, 211, 229, 241];
-
-function addSubscriptionFilters(subscription)
-{
-  // We add filters using pseudo-random ordering. Reason is that ElemHide will
-  // assign consecutive filter IDs that might be visible to the website. The
-  // randomization makes sure that no conclusion can be made about the actual
-  // filters applying there. We have ten prime numbers to use as iteration step,
-  // any of those can be chosen as long as the array length isn't divisible by
-  // it.
-  let len = subscription.filterCount;
-  if (!len)
-    return;
-
-  let current = (Math.random() * len) | 0;
-  let step;
-  do
-  {
-    step = primes[(Math.random() * primes.length) | 0];
-  } while (len % step == 0);
-
-  for (let i = 0; i < len; i++, current = (current + step) % len)
-    addFilter(subscription.filterAt(current));
-}
-
 function onSubscriptionAdded(subscription)
 {
   FilterListener.setDirty(1);
 
   if (!subscription.disabled)
-    addSubscriptionFilters(subscription);
+  {
+    for (let filter of subscription.filters())
+      addFilter(filter);
+  }
 }
 
 function onSubscriptionRemoved(subscription)
 {
   FilterListener.setDirty(1);
 
   if (!subscription.disabled)
   {
     for (let filter of subscription.filters())
       removeFilter(filter);
   }
 }
 
 function onSubscriptionDisabled(subscription, newValue)
 {
   FilterListener.setDirty(1);
 
   if (filterStorage.knownSubscriptions.has(subscription.url))
   {
     if (newValue == false)
     {
-      addSubscriptionFilters(subscription);
+      for (let filter of subscription.filters())
+        addFilter(filter);
     }
     else
     {
       for (let filter of subscription.filters())
         removeFilter(filter);
     }
   }
 }
 
 function onSubscriptionUpdated(subscription, oldFilters)
 {
   FilterListener.setDirty(1);
 
   if (!subscription.disabled &&
       filterStorage.knownSubscriptions.has(subscription.url))
   {
     for (let filter of oldFilters)
       removeFilter(filter);
 
-    addSubscriptionFilters(subscription);
+    for (let filter of subscription.filters())
+      addFilter(filter);
   }
 }
 
 function onFilterHitCount(filter, newValue)
 {
   if (newValue == 0)
     FilterListener.setDirty(0);
   else
     FilterListener.setDirty(0.002);
 }
@@ skipping 40 matching lines @@
 
   defaultMatcher.clear();
   ElemHide.clear();
   ElemHideEmulation.clear();
   ElemHideExceptions.clear();
   Snippets.clear();
 
   for (let subscription of filterStorage.subscriptions())
   {
     if (!subscription.disabled)
-      addSubscriptionFilters(subscription);
+    {
+      for (let filter of subscription.filters())
+        addFilter(filter);
+    }
   }
 }
 
 function onSave()
 {
   isDirty = 0;
 }