Issue 6665 - Optimize element hiding emulation filter lookups

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 {ElemHide} = require("./elemHide");
-const {filterIt, mapIt, flattenIt, regExpIt} = require("./coreUtils");
+const {subdomains} = require("./common");
 
 /**
  * Map of element hiding emulation filters by domain
- * @type {Map.<string,Set.<ElemHideEmulationFilter>>}
+ * @type {Map.<string,Map.<ElemHideEmulationFilter,boolean>>}
  */
 let filtersByDomain = new Map();
 
 /**
  * Set containing known element hiding emulation filters
  * @type {Set.<ElemHideEmulation>}
  */
 let knownFilters = new Set();
 
+/**
+ * Yields the domains associated with a filter, along with whether the filter
+ * should be included on the domain and the set of filters associated with the
+ * domain
+ * @param {ElemHideEmulationFilter} filter
+ * @yields {Array.<string,boolean,?Set.<ElemHideEmulationFilter>>}
+ */
 function* filterDomains(filter)
 {
-  yield* mapIt(filterIt(filter.domains || [], ([domain]) => domain != ""),
-               ([domain, include]) => [domain, include,
-                                       filtersByDomain.get(domain)]);
+  for (let [domain, include] of filter.domains || [])
+  {
+    if (domain != "")
+      yield [domain, include, filtersByDomain.get(domain)];
+  }
 }
 
+/**
+ * Yields the filters for a domain and its subdomains, along with whether the
+ * filter should be included on its corresponding domain
+ * @param {string} domain
+ * @yields {Array.<ElemHideEmulationFilter,boolean>}
+ */
 function* filtersForDomain(domain)
 {
   yield* filtersByDomain.get(domain) || [];
 
-  let subdomainIt =
-    mapIt(regExpIt(/([^|]*)\|/g, domain.replace(/([^.]+\.)/g, "$'|")),
-          ([, subdomain]) => filtersByDomain.get(subdomain) || []);
-  yield* flattenIt(subdomainIt);
+  for (let subdomain of subdomains(domain))
+    yield* filtersByDomain.get(subdomain) || [];
 }
 
 /**
  * Container for element hiding emulation filters
  * @class
  */
 let ElemHideEmulation = {
   /**
    * Removes all known filters
    */
@@ skipping 65 matching lines @@
                !ElemHide.getException(filter, domain))
       {
         result.push(filter);
       }
     }
 
     return result;
   }
 };
 exports.ElemHideEmulation = ElemHideEmulation;