Issue 7094 - Encapsulate management of subscription filters

lib/filterListener.js

Index: lib/filterListener.js
===================================================================
--- a/lib/filterListener.js
+++ b/lib/filterListener.js
@@ -214,77 +214,87 @@
       ElemHideExceptions.remove(filter);
   }
   else if (filter instanceof SnippetFilter)
     Snippets.remove(filter);
 }
 
 const primes = [101, 109, 131, 149, 163, 179, 193, 211, 229, 241];
 
-function addFilters(filters)
+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 = filters.length;
+  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(filters[current]);
+    addFilter(subscription.filterAt(current));
 }
 
 function onSubscriptionAdded(subscription)
 {
   FilterListener.setDirty(1);
 
   if (!subscription.disabled)
-    addFilters(subscription.filters);
+    addSubscriptionFilters(subscription);
 }
 
 function onSubscriptionRemoved(subscription)
 {
   FilterListener.setDirty(1);
 
   if (!subscription.disabled)
-    subscription.filters.forEach(removeFilter);
+  {
+    for (let filter of subscription.filters())
+      removeFilter(filter);
+  }
 }
 
 function onSubscriptionDisabled(subscription, newValue)
 {
   FilterListener.setDirty(1);
 
   if (filterStorage.knownSubscriptions.has(subscription.url))
   {
     if (newValue == false)
-      addFilters(subscription.filters);
+    {
+      addSubscriptionFilters(subscription);
+    }
     else
-      subscription.filters.forEach(removeFilter);
+    {
+      for (let filter of subscription.filters())
+        removeFilter(filter);
+    }
   }
 }
 
 function onSubscriptionUpdated(subscription, oldFilters)
 {
   FilterListener.setDirty(1);
 
   if (!subscription.disabled &&
       filterStorage.knownSubscriptions.has(subscription.url))
   {
-    oldFilters.forEach(removeFilter);
-    addFilters(subscription.filters);
+    for (let filter of oldFilters)
+      removeFilter(filter);
+
+    addSubscriptionFilters(subscription);
   }
 }
 
 function onFilterHitCount(filter, newValue)
 {
   if (newValue == 0)
     FilterListener.setDirty(0);
   else
@@ -334,16 +344,18 @@
   defaultMatcher.clear();
   ElemHide.clear();
   ElemHideEmulation.clear();
   ElemHideExceptions.clear();
   Snippets.clear();
   for (let subscription of filterStorage.subscriptions())
   {
     if (!subscription.disabled)
-      addFilters(subscription.filters);
+      addSubscriptionFilters(subscription);
+
+    subscription.freeFilters();
   }
 }
 
 function onSave()
 {
   isDirty = 0;
 }