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

lib/elemHide.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 implementation.
  */
 
+const {ContentFilterModule} = require("./contentFilterModule");
 const {ElemHideExceptions} = require("./elemHideExceptions");
 const {FilterNotifier} = require("./filterNotifier");
-
-/**
- * Map to be used instead when a filter has a blank domains property.
- * @type {Map.<string,boolean>}
- * @const
- */
-let defaultDomains = new Map([["", true]]);
-
-/**
- * Template for element hiding and element hiding emulation filter containers
- * @class
- */
-function ElemHideTemplate()
-{
-  this._filtersByDomain = new Map();
-  this._filterBySelector = new Map();
-  this._unconditionalSelectors = null;
-  this._knownFilters = new Set();
-
-  ElemHideExceptions.on("added", this._onExceptionAdded.bind(this));
-}
-
-ElemHideTemplate.prototype = {
-  /**
-   * Lookup table, active flag, by filter by domain.
-   * (Only contains filters that aren't unconditionally matched for all
-   * domains.)
-   * @type {Map.<string,Map.<Filter,boolean>>}
-   */
-  _filtersByDomain: null,
-
-  /**
-   * Lookup table, filter by selector. (Only used for selectors that are
-   * unconditionally matched for all domains.)
-   * @type {Map.<string,Filter>}
-   */
-  _filterBySelector: null,
-
-  /**
-   * This array caches the keys of _filterBySelector table (selectors
-   * which unconditionally apply on all domains). It will be null if the
-   * cache needs to be rebuilt.
-   * @type {?string[]}
-   */
-  _unconditionalSelectors: null,
-
-  /**
-   * Set containing known element hiding filters
-   * @type {Set.<ElemHideFilter>}
-   */
-  _knownFilters: null,
-
-  /**
-   * Adds a filter to the lookup table of filters by domain.
-   * @param {Filter} filter
-   */
-  _addToFiltersByDomain(filter)
-  {
-    let domains = filter.domains || defaultDomains;
-    for (let [domain, isIncluded] of domains)
-    {
-      // There's no need to note that a filter is generically disabled.
-      if (!isIncluded && domain == "")
-        continue;
-
-      let filters = this._filtersByDomain.get(domain);
-      if (!filters)
-        this._filtersByDomain.set(domain, filters = new Map());
-      filters.set(filter, isIncluded);
-    }
-  },
-
-  /**
-   * Returns a list of selectors that apply on each website unconditionally.
-   * @returns {string[]}
-   */
-  _getUnconditionalSelectors()
-  {
-    if (!this._unconditionalSelectors)
-      this._unconditionalSelectors = [...this._filterBySelector.keys()];
-
-    return this._unconditionalSelectors;
-  },
-
-  /**
-   * Handles the event when a new element hiding exception has been added
-   * @param {ElemHideException} exception
-   */
-  _onExceptionAdded(exception)
-  {
-    let {selector} = exception;
-
-    // If this is the first exception for a previously unconditionally applied
-    // element hiding selector we need to take care to update the lookups.
-    let unconditionalFilterForSelector = this._filterBySelector.get(selector);
-    if (unconditionalFilterForSelector)
-    {
-      this._addToFiltersByDomain(unconditionalFilterForSelector);
-      this._filterBySelector.delete(selector);
-      this._unconditionalSelectors = null;
-    }
-  },
-
-  /**
-   * Removes all known filters
-   */
-  clear()
-  {
-    for (let collection of [this._filtersByDomain, this._filterBySelector,
-                            this._knownFilters])
-    {
-      collection.clear();
-    }
-    this._unconditionalSelectors = null;
-    FilterNotifier.emit("elemhideupdate");
-  },
-
-  /**
-   * Add a new element hiding filter
-   * @param {ElemHideFilter} filter
-   */
-  add(filter)
-  {
-    if (this._knownFilters.has(filter))
-      return;
-
-    if (!(filter.domains || ElemHideExceptions.hasExceptions(filter.selector)))
-    {
-      // The new filter's selector is unconditionally applied to all domains
-      this._filterBySelector.set(filter.selector, filter);
-      this._unconditionalSelectors = null;
-    }
-    else
-    {
-      // The new filter's selector only applies to some domains
-      this._addToFiltersByDomain(filter);
-    }
-
-    this._knownFilters.add(filter);
-    FilterNotifier.emit("elemhideupdate");
-  },
-
-  /**
-   * Removes an element hiding filter
-   * @param {ElemHideFilter} filter
-   */
-  remove(filter)
-  {
-    if (!this._knownFilters.has(filter))
-      return;
-
-    // Unconditially applied element hiding filters
-    if (this._filterBySelector.get(filter.selector) == filter)
-    {
-      this._filterBySelector.delete(filter.selector);
-      this._unconditionalSelectors = null;
-    }
-    // Conditionally applied element hiding filters
-    else
-    {
-      let domains = filter.domains || defaultDomains;
-      for (let domain of domains.keys())
-      {
-        let filters = this._filtersByDomain.get(domain);
-        if (filters)
-          filters.delete(filter);
-      }
-    }
-
-    this._knownFilters.delete(filter);
-    FilterNotifier.emit("elemhideupdate");
-  }
-};
-
-exports.ElemHideTemplate = ElemHideTemplate;
 
 /**
  * Container for element hiding filters
  * @class
  */
-exports.ElemHide = Object.assign(new ElemHideTemplate(), {
+exports.ElemHide = Object.assign(new ContentFilterModule(), {
+  clear()
+  {
+    ContentFilterModule.prototype.clear.call(this);
+
+    FilterNotifier.emit("elemhideupdate");
+  },
+
+  add(filter)
+  {
+    let {size} = this._knownFilters;
+
+    ContentFilterModule.prototype.add.call(this, filter);
+
+    if (size != this._knownFilters.size)
+      FilterNotifier.emit("elemhideupdate");
+  },
+
+  remove(filter)
+  {
+    let {size} = this._knownFilters;
+
+    ContentFilterModule.prototype.remove.call(this, filter);
+
+    if (size != this._knownFilters.size)
+      FilterNotifier.emit("elemhideupdate");
+  },
+
   /**
    * Determines from the current filter list which selectors should be applied
    * on a particular host name.
    * @param {string} domain
    * @param {boolean} [specificOnly] true if generic filters should not apply.
    * @returns {string[]} List of selectors.
    */
   getSelectorsForDomain(domain, specificOnly = false)

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

Code that is specific to ElemHide is still in the ElemHide object only.

   {
     let selectors = [];
 
     let excluded = new Set();
-    let currentDomain = domain ? domain.toUpperCase() : "";
+    let currentDomain = domain ? domain.replace(/\.+$/, "").toLowerCase() : "";
 
     // This code is a performance hot-spot, which is why we've made certain
     // micro-optimisations. Please be careful before making changes.
     while (true)
     {
       if (specificOnly && currentDomain == "")
         break;
 
       let filters = this._filtersByDomain.get(currentDomain);
       if (filters)
       {
         for (let [filter, isIncluded] of filters)
         {
           if (!isIncluded)
           {
             excluded.add(filter);
           }
-          else if ((excluded.size == 0 || !excluded.has(filter)) &&
-                   !ElemHideExceptions.getException(filter, domain))
+          else
           {
-            selectors.push(filter.selector);
+            let {selector} = filter;
+            if ((excluded.size == 0 || !excluded.has(filter)) &&
+                !ElemHideExceptions.getException(selector, domain))
+            {
+              selectors.push(selector);
+            }
           }
         }
       }
 
       if (currentDomain == "")
         break;
 
       let nextDot = currentDomain.indexOf(".");
       currentDomain = nextDot == -1 ? "" : currentDomain.substr(nextDot + 1);
     }
 
     if (!specificOnly)
       selectors = this._getUnconditionalSelectors().concat(selectors);
 
     return selectors;
   }
 });