Issue 6665 - Abstract element hiding container logic into its own module

lib/elemHideEmulation.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 Element hiding emulation implementation.
  */
 
+const {ElemHideTemplate} = require("./elemHide");
 const {ElemHideExceptions} = require("./elemHideExceptions");
-const {Filter} = require("./filterClasses");
-
-let filters = new Set();
 
 /**
  * Container for element hiding emulation filters
  * @class
  */
-let ElemHideEmulation = {
-  /**
-   * Removes all known filters
-   */
-  clear()
-  {
-    filters.clear();
-  },
-
-  /**
-   * Add a new element hiding emulation filter
-   * @param {ElemHideEmulationFilter} filter
-   */
-  add(filter)
-  {
-    filters.add(filter.text);
-  },
-
-  /**
-   * Removes an element hiding emulation filter
-   * @param {ElemHideEmulationFilter} filter
-   */
-  remove(filter)
-  {
-    filters.delete(filter.text);
-  },
-
+exports.ElemHideEmulation = Object.assign(new ElemHideTemplate(), {

[Manish Jethani, 2018/05/17 05:51:54]

ElemHideEmulation is now just like ElemHide, but with its own copy of the data
structures containing its own filters. Exceptions are still shared via the new
ElemHideExceptions module.

   /**
    * Returns a list of all rules active on a particular domain
    * @param {string} domain
    * @return {ElemHideEmulationFilter[]}
    */
   getRulesForDomain(domain)
   {
     let result = [];
-    for (let text of filters.values())
+    for (let filter of this._knownFilters)

[Manish Jethani, 2018/05/17 05:51:54]

Note: I am not yet taking advantage of the optimizations in ElemHide for filter
matching. That will require some more refactoring in ElemHideTemplate, it will
be a follow-up patch.

     {
-      let filter = Filter.fromText(text);
       if (filter.isActiveOnDomain(domain) &&
           !ElemHideExceptions.getException(filter, domain))
       {
         result.push(filter);
       }
     }
     return result;
   }
-};
-exports.ElemHideEmulation = ElemHideEmulation;
+});