Issue 7094 - Encapsulate management of subscription filters

lib/filterStorage.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 179 matching lines @@
     filterNotifier.emit("subscription.removed", subscription);
   }
 
   /**
    * Replaces the list of filters in a subscription with a new list.
    * @param {Subscription} subscription The subscription to be updated.
    * @param {Array.<Filter>} filters The new list of filters.
    */
   updateSubscriptionFilters(subscription, filters)
   {
-    disconnectSubscriptionFilters(subscription);
-
     let oldFilters = [...subscription.filters()];
+    disconnectSubscriptionFilters(subscription, oldFilters);
     subscription.clearFilters();
+
     for (let filter of filters)
       subscription.addFilter(filter);
 
     connectSubscriptionFilters(subscription, filters);
+
     filterNotifier.emit("subscription.updated", subscription, oldFilters);
   }
 
   /**
    * Adds a user-defined filter to the storage.
    * @param {Filter} filter
    * @param {?SpecialSubscription} [subscription] The subscription that the
    *   filter should be added to.
    * @param {number} [position] The position within the subscription at which
    *   the filter should be added. If not specified, the filter is added at the
@@ skipping 457 matching lines @@
  *   subscription is disconnected from its own filters.
  */
 function disconnectSubscriptionFilters(subscription, filters)
 {
   if (!filterStorage.knownSubscriptions.has(subscription.url))
     return;
 
   for (let filter of filters || subscription.filters())
     filter.removeSubscription(subscription);
 }