Issue 7097 - Make element hiding filter objects ephemeral

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,
+const {Filter, ActiveFilter, BlockingFilter,
        WhitelistFilter, ElemHideBase} = require("./filterClasses");
 const {filterNotifier} = require("./filterNotifier");
 const {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
@@ skipping 126 matching lines @@
   {
     yield* this._filterText;
   },
 
   /**
    * Yields the {@link Filter} object for each filter in the subscription.
    * @yields {Filter}
    */
   *filters()
   {
-    yield* this._filters;
+    for (let i = 0; i < this._filters.length; i++)
+      yield this._filters[i] || Filter.fromText(this._filterText[i]);
   },
 
   /**
    * Returns the {@link Filter} object at the given 0-based index.
    * @param {number} index
    * @returns {?Filter}
    */
   filterAt(index)
   {
-    return this._filters[index] || null;
+    return this._filters[index] ||
+           (index >= 0 && index < this._filters.length ?
+              Filter.fromText(this._filterText[index]) : null);
   },
 
   /**
    * Returns the 0-based index of the given filter.
    * @param {Filter} filter
    * @param {number} [fromIndex] The index from which to start the search.
    * @return {number}
    */
   searchFilter(filter, fromIndex = 0)
   {
@@ skipping 65 matching lines @@
 
     this._filterTextLookup = null;
   },
 
   /**
    * Clears any in-memory caches held by the object.
    * @package
    */
   clearCaches()
   {
+    for (let i = 0; i < this._filters.length; i++)
+    {
+      if (this._filters[i] && this._filters[i].ephemeral)

[Manish Jethani, 2018/11/18 03:29:12]

filterClasses.js doesn't keep any references to ephemeral filter objects now.
Here we lose the only remaining references (after applying all the pathces).
This method is called by filterStorage.js after it dispatches the "load" event
and all the listeners have finished their business.

+        this._filters[i] = null;
+    }
+
     this._filterTextLookup = null;
   },
 
   /**
    * Serializes the subscription for writing out on disk.
    * @yields {string}
    */
   *serialize()
   {
     let {url, type, _title, _fixedTitle, _disabled} = this;
@@ skipping 448 matching lines @@
     if (errors)
       yield "errors=" + errors;
     if (version)
       yield "version=" + version;
     if (requiredVersion)
       yield "requiredVersion=" + requiredVersion;
     if (downloadCount)
       yield "downloadCount=" + downloadCount;
   }
 });