Issue 6564 - Replace desc and extend with __proto__

lib/subscriptionClasses.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
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 "use strict";
 
 /**
  * @fileOverview Definition of Subscription class and its subclasses.
  */
 
 const {ActiveFilter, BlockingFilter,
        WhitelistFilter, ElemHideBase} = require("./filterClasses");
 const {FilterNotifier} = require("./filterNotifier");
-const {desc, extend} = require("./coreUtils");
 
 /**
  * Abstract base class for filter subscriptions
  *
  * @param {string} url    download location of the subscription
  * @param {string} [title]  title of the filter subscription
  * @constructor
  */
 function Subscription(url, title)
 {
@@ skipping 195 matching lines @@
  * @param {string} [title]  see Subscription()
  * @constructor
  * @augments Subscription
  */
 function SpecialSubscription(url, title)
 {
   Subscription.call(this, url, title);
 }
 exports.SpecialSubscription = SpecialSubscription;
 
-SpecialSubscription.prototype = extend(Subscription, {
+SpecialSubscription.prototype = {
+  __proto__: Subscription.prototype,
+
   /**
    * Filter types that should be added to this subscription by default
    * (entries should correspond to keys in SpecialSubscription.defaultsMap).
    * @type {string[]}
    */
   defaults: null,
 
   /**
    * Tests whether a filter should be added to this group by default
    * @param {Filter} filter filter to be tested
@@ skipping 26 matching lines @@
     {
       buffer.push("defaults=" +
         this.defaults.filter(
           type => type in SpecialSubscription.defaultsMap
         ).join(" ")
       );
     }
     if (this._lastDownload)
       buffer.push("lastDownload=" + this._lastDownload);
   }
-});
+};
 
-SpecialSubscription.defaultsMap = Object.create(null, desc({
+SpecialSubscription.defaultsMap = {
+  __proto__: null,
   whitelist: WhitelistFilter,
   blocking: BlockingFilter,
   elemhide: ElemHideBase
-}));
+};
 
 /**
  * Creates a new user-defined filter group.
  * @param {string} [title]  title of the new filter group
  * @return {SpecialSubscription}
  */
 SpecialSubscription.create = function(title)
 {
   let url;
   do
@@ skipping 30 matching lines @@
  * @param {string} [title]  see Subscription()
  * @constructor
  * @augments Subscription
  */
 function RegularSubscription(url, title)
 {
   Subscription.call(this, url, title || url);
 }
 exports.RegularSubscription = RegularSubscription;
 
-RegularSubscription.prototype = extend(Subscription, {
+RegularSubscription.prototype = {
+  __proto__: Subscription.prototype,
+
   _homepage: null,
   _lastDownload: 0,
 
   /**
    * Filter subscription homepage if known
    * @type {string}
    */
   get homepage()
   {
     return this._homepage;
@@ skipping 36 matching lines @@
    * @inheritdoc
    */
   serialize(buffer)
   {
     Subscription.prototype.serialize.call(this, buffer);
     if (this._homepage)
       buffer.push("homepage=" + this._homepage);
     if (this._lastDownload)
       buffer.push("lastDownload=" + this._lastDownload);
   }
-});
+};
 
 /**
  * Class for filter subscriptions updated externally (by other extension)
  * @param {string} url    see Subscription()
  * @param {string} [title]  see Subscription()
  * @constructor
  * @augments RegularSubscription
  */
 function ExternalSubscription(url, title)
 {
   RegularSubscription.call(this, url, title);
 }
 exports.ExternalSubscription = ExternalSubscription;
 
-ExternalSubscription.prototype = extend(RegularSubscription, {
+ExternalSubscription.prototype = {
+  __proto__: RegularSubscription.prototype,
+
   /**
    * See Subscription.serialize()
    * @inheritdoc
    */
   serialize(buffer)
   {
     throw new Error(
       "Unexpected call, external subscriptions should not be serialized"
     );
   }
-});
+};
 
 /**
  * Class for filter subscriptions updated externally (by other extension)
  * @param {string} url  see Subscription()
  * @param {string} [title]  see Subscription()
  * @constructor
  * @augments RegularSubscription
  */
 function DownloadableSubscription(url, title)
 {
   RegularSubscription.call(this, url, title);
 }
 exports.DownloadableSubscription = DownloadableSubscription;
 
-DownloadableSubscription.prototype = extend(RegularSubscription, {
+DownloadableSubscription.prototype = {
+  __proto__: RegularSubscription.prototype,
+
   _downloadStatus: null,
   _lastCheck: 0,
   _errors: 0,
 
   /**
    * Status of the last download (ID of a string)
    * @type {string}
    */
   get downloadStatus()
   {
@@ skipping 108 matching lines @@
       buffer.push("softExpiration=" + this.softExpiration);
     if (this.errors)
       buffer.push("errors=" + this.errors);
     if (this.version)
       buffer.push("version=" + this.version);
     if (this.requiredVersion)
       buffer.push("requiredVersion=" + this.requiredVersion);
     if (this.downloadCount)
       buffer.push("downloadCount=" + this.downloadCount);
   }
-});
+};