Issue 6815 - Avoid multiple copies of domain maps

lib/filterClasses.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 386 matching lines @@
    */
   domainSourceIsLowerCase: false,
 
   /**
    * Map containing domains that this filter should match on/not match
    * on or null if the filter should match on all domains
    * @type {?Map.<string,boolean>}
    */
   get domains()
   {
-    let prop = Object.getOwnPropertyDescriptor(this, "_domains");
-    if (prop)
-    {
-      let {value} = prop;
-      return typeof value == "string" ?
-               new Map([[value, true], ["", false]]) : value;
-    }
-
     let domains = null;
 
     if (this.domainSource)
     {
       let source = this.domainSource;
       if (!this.domainSourceIsLowerCase)
       {
         // RegExpFilter already have lowercase domains
         source = source.toLowerCase();
       }
 
       let knownMap = knownDomainMaps.get(source);
       if (knownMap)
       {
         domains = knownMap;
       }
       else
       {
         let list = source.split(this.domainSeparator);
         if (list.length == 1 && list[0][0] != "~")
         {
           // Fast track for the common one-domain scenario
-          domains = list[0];
+          domains = new Map([[list[0], true], ["", false]]);
         }
         else
         {
           let hasIncludes = false;
           for (let i = 0; i < list.length; i++)
           {
             let domain = list[i];
             if (domain == "")
               continue;
 
             let include;
             if (domain[0] == "~")
             {
               include = false;
               domain = domain.substr(1);
             }
             else
             {
               include = true;
               hasIncludes = true;
             }
 
             if (!domains)
               domains = new Map();
 
             domains.set(domain, include);
           }
 
           if (domains)
-          {
             domains.set("", !hasIncludes);
-            knownDomainMaps.set(source, domains);
-          }
         }
+
+        if (domains)
+          knownDomainMaps.set(source, domains);
       }
 
       this.domainSource = null;
     }
 
-    Object.defineProperty(this, "_domains", {value: domains});
+    Object.defineProperty(this, "domains", {value: domains});
     return this.domains;
   },
 
   /**
    * Array containing public keys of websites that this filter should apply to
    * @type {?string[]}
    */
   sitekeys: null,
 
   /**
@@ skipping 703 matching lines @@
 
   /**
    * Script that should be executed
    * @type {string}
    */
   get script()
   {
     return this.body;
   }
 });