Issue 5735 - Use JS Map instead of Object for matcher properties filterByKeyword and keywordByFilter

lib/matcher.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
@@ skipping 19 matching lines @@
  */
 function Matcher()
 {
   this.clear();
 }
 exports.Matcher = Matcher;
 
 Matcher.prototype = {
   /**
    * Lookup table for filters by their associated keyword
-   * @type {Object}
+   * @type {Map.<string,Filter>}
    */
   filterByKeyword: null,
 
   /**
-   * Lookup table for keywords by the filter text
-   * @type {Object}
+   * Lookup table for keywords by the filter
+   * @type {Map.<Filter,string>}
    */
   keywordByFilter: null,
 
   /**
    * Removes all known filters
    */
   clear()
   {
-    this.filterByKeyword = Object.create(null);
-    this.keywordByFilter = Object.create(null);
+    this.filterByKeyword = new Map();
+    this.keywordByFilter = new Map();
   },
 
   /**
    * Adds a filter to the matcher
    * @param {RegExpFilter} filter
    */
   add(filter)
   {
-    if (filter.text in this.keywordByFilter)
+    if (this.keywordByFilter.has(filter))
       return;
 
     // Look for a suitable keyword
     let keyword = this.findKeyword(filter);
-    let oldEntry = this.filterByKeyword[keyword];
+    let oldEntry = this.filterByKeyword.get(keyword);
     if (typeof oldEntry == "undefined")
-      this.filterByKeyword[keyword] = filter;
+      this.filterByKeyword.set(keyword, filter);
     else if (oldEntry.length == 1)
-      this.filterByKeyword[keyword] = [oldEntry, filter];
+      this.filterByKeyword.set(keyword, [oldEntry, filter]);
     else
       oldEntry.push(filter);
-    this.keywordByFilter[filter.text] = keyword;
+    this.keywordByFilter.set(filter, keyword);
   },
 
   /**
    * Removes a filter from the matcher
    * @param {RegExpFilter} filter
    */
   remove(filter)
   {
-    if (!(filter.text in this.keywordByFilter))
+    let keyword = this.keywordByFilter.get(filter);
+    if (typeof keyword == "undefined")
       return;
 
-    let keyword = this.keywordByFilter[filter.text];
-    let list = this.filterByKeyword[keyword];
+    let list = this.filterByKeyword.get(keyword);
     if (list.length <= 1)
-      delete this.filterByKeyword[keyword];
+      this.filterByKeyword.delete(keyword);
     else
     {
       let index = list.indexOf(filter);
       if (index >= 0)
       {
         list.splice(index, 1);
         if (list.length == 1)
-          this.filterByKeyword[keyword] = list[0];
+          this.filterByKeyword.set(keyword, list[0]);
       }
     }
 
-    delete this.keywordByFilter[filter.text];
+    this.keywordByFilter.delete(filter);
   },
 
   /**
    * Chooses a keyword to be associated with the filter
    * @param {Filter} filter
    * @return {string} keyword or an empty string if no keyword could be found
    */
   findKeyword(filter)
   {
     let result = "";
@@ skipping 15 matching lines @@
     );
     if (!candidates)
       return result;
 
     let hash = this.filterByKeyword;
     let resultCount = 0xFFFFFF;
     let resultLength = 0;
     for (let i = 0, l = candidates.length; i < l; i++)
     {
       let candidate = candidates[i].substr(1);
-      let count = (candidate in hash ? hash[candidate].length : 0);
+      let filters = hash.get(candidate);
+      let count = typeof filters != "undefined" ? filters.length : 0;
       if (count < resultCount ||
           (count == resultCount && candidate.length > resultLength))
       {
         result = candidate;
         resultCount = count;
         resultLength = candidate.length;
       }
     }
     return result;
   },
 
   /**
    * Checks whether a particular filter is being matched against.
    * @param {RegExpFilter} filter
    * @return {boolean}
    */
   hasFilter(filter)
   {
-    return (filter.text in this.keywordByFilter);
+    return this.keywordByFilter.has(filter);
   },
 
   /**
    * Returns the keyword used for a filter, null for unknown filters.
    * @param {RegExpFilter} filter
-   * @return {string}
+   * @return {?string}
    */
   getKeywordForFilter(filter)
   {
-    if (filter.text in this.keywordByFilter)
-      return this.keywordByFilter[filter.text];
-    return null;
+    let keyword = this.keywordByFilter.get(filter);
+    return typeof keyword != "undefined" ? keyword : null;
   },
 
   /**
    * Checks whether the entries for a particular keyword match a URL
    * @param {string} keyword
    * @param {string} location
    * @param {number} typeMask
    * @param {string} docDomain
    * @param {boolean} thirdParty
    * @param {string} sitekey
    * @param {boolean} specificOnly
    * @return {?Filter}
    */
   _checkEntryMatch(keyword, location, typeMask, docDomain, thirdParty, sitekey,
                    specificOnly)
   {
-    let list = this.filterByKeyword[keyword];
+    let list = this.filterByKeyword.get(keyword);
+    if (typeof list == "undefined")
+      return null;
     for (let i = 0; i < list.length; i++)
     {
       let filter = list[i];
 
       if (specificOnly && filter.isGeneric() &&
           !(filter instanceof WhitelistFilter))
         continue;
 
       if (filter.matches(location, typeMask, docDomain, thirdParty, sitekey))
         return filter;
@@ skipping 19 matching lines @@
    *   matching filter or null
    */
   matchesAny(location, typeMask, docDomain, thirdParty, sitekey, specificOnly)
   {
     let candidates = location.toLowerCase().match(/[a-z0-9%]{3,}/g);
     if (candidates === null)
       candidates = [];
     candidates.push("");
     for (let i = 0, l = candidates.length; i < l; i++)
     {
-      let substr = candidates[i];
-      if (substr in this.filterByKeyword)
-      {
-        let result = this._checkEntryMatch(substr, location, typeMask,
-                                           docDomain, thirdParty, sitekey,
-                                           specificOnly);
-        if (result)
-          return result;
-      }
+      let result = this._checkEntryMatch(candidates[i], location, typeMask,
+                                         docDomain, thirdParty, sitekey,
+                                         specificOnly);
+      if (result)
+        return result;
     }
 
     return null;
   }
 };
 
 /**
  * Combines a matcher for blocking and exception rules, automatically sorts
  * rules into two Matcher instances.
  * @constructor
@@ skipping 148 matching lines @@
   {
     let candidates = location.toLowerCase().match(/[a-z0-9%]{3,}/g);
     if (candidates === null)
       candidates = [];
     candidates.push("");
 
     let blacklistHit = null;
     for (let i = 0, l = candidates.length; i < l; i++)
     {
       let substr = candidates[i];
-      if (substr in this.whitelist.filterByKeyword)
-      {
-        let result = this.whitelist._checkEntryMatch(
-          substr, location, typeMask, docDomain, thirdParty, sitekey
-        );
-        if (result)
-          return result;
-      }
-      if (substr in this.blacklist.filterByKeyword && blacklistHit === null)
+      let result = this.whitelist._checkEntryMatch(
+        substr, location, typeMask, docDomain, thirdParty, sitekey
+      );
+      if (result)
+        return result;
+      if (blacklistHit === null)
       {
         blacklistHit = this.blacklist._checkEntryMatch(
           substr, location, typeMask, docDomain, thirdParty, sitekey,
           specificOnly
         );
       }
     }
     return blacklistHit;
   },
 
@@ skipping 22 matching lines @@
 
     return result;
   }
 };
 
 /**
  * Shared CombinedMatcher instance that should usually be used.
  * @type {CombinedMatcher}
  */
 exports.defaultMatcher = new CombinedMatcher();