Issue 4878 - Start using ESLint for adblockpluscore

lib/matcher.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 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 Matcher class implementing matching addresses against a list of filters.
+ * @fileOverview Matcher class implementing matching addresses against
+ *               a list of filters.
  */
 
-let {Filter, RegExpFilter, WhitelistFilter} = require("filterClasses");
+const {Filter, RegExpFilter, WhitelistFilter} = require("filterClasses");
 
 /**
  * Blacklist/whitelist filter matching
  * @constructor
  */
 function Matcher()
 {
   this.clear();
 }
 exports.Matcher = Matcher;
 
 Matcher.prototype = {
   /**
    * Lookup table for filters by their associated keyword
-   * @type Object
+   * @type {Object}
    */
   filterByKeyword: null,
 
   /**
    * Lookup table for keywords by the filter text
-   * @type Object
+   * @type {Object}
    */
   keywordByFilter: null,
 
   /**
    * Removes all known filters
    */
-  clear: function()
+  clear()
   {
     this.filterByKeyword = Object.create(null);
     this.keywordByFilter = Object.create(null);
   },
 
   /**
    * Adds a filter to the matcher
    * @param {RegExpFilter} filter
    */
-  add: function(filter)
+  add(filter)
   {
     if (filter.text in this.keywordByFilter)
       return;
 
     // Look for a suitable keyword
     let keyword = this.findKeyword(filter);
     let oldEntry = this.filterByKeyword[keyword];
     if (typeof oldEntry == "undefined")
       this.filterByKeyword[keyword] = filter;
     else if (oldEntry.length == 1)
       this.filterByKeyword[keyword] = [oldEntry, filter];
     else
       oldEntry.push(filter);
     this.keywordByFilter[filter.text] = keyword;
   },
 
   /**
    * Removes a filter from the matcher
    * @param {RegExpFilter} filter
    */
-  remove: function(filter)
+  remove(filter)
   {
     if (!(filter.text in this.keywordByFilter))
       return;
 
     let keyword = this.keywordByFilter[filter.text];
     let list = this.filterByKeyword[keyword];
     if (list.length <= 1)
       delete this.filterByKeyword[keyword];
     else
     {
       let index = list.indexOf(filter);
       if (index >= 0)
       {
         list.splice(index, 1);
         if (list.length == 1)
           this.filterByKeyword[keyword] = list[0];
       }
     }
 
     delete this.keywordByFilter[filter.text];
   },
 
   /**
    * Chooses a keyword to be associated with the filter
-   * @param {String} text text representation of the filter
-   * @return {String} keyword (might be empty string)
+   * @param {Filter} filter
+   * @return {string} keyword
    */
-  findKeyword: function(filter)
+  findKeyword(filter)
   {
     let result = "";
-    let text = filter.text;
+    let {text} = filter;
     if (Filter.regexpRegExp.test(text))
       return result;
 
     // Remove options
     let match = Filter.optionsRegExp.exec(text);
     if (match)
       text = match.input.substr(0, match.index);
 
     // Remove whitelist marker
     if (text.substr(0, 2) == "@@")
       text = text.substr(2);
 
-    let candidates = text.toLowerCase().match(/[^a-z0-9%*][a-z0-9%]{3,}(?=[^a-z0-9%*])/g);
+    let candidates = text.toLowerCase().match(
+      /[^a-z0-9%*][a-z0-9%]{3,}(?=[^a-z0-9%*])/g
+    );
     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);
-      if (count < resultCount || (count == resultCount && candidate.length > resultLength))
+      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: function(/**RegExpFilter*/ filter) /**Boolean*/
+  hasFilter(filter)
   {
     return (filter.text in this.keywordByFilter);
   },
 
   /**
    * Returns the keyword used for a filter, null for unknown filters.
+   * @param {RegExpFilter} filter
+   * @return {string}
    */
-  getKeywordForFilter: function(/**RegExpFilter*/ filter) /**String*/
+  getKeywordForFilter(filter)
   {
     if (filter.text in this.keywordByFilter)
       return this.keywordByFilter[filter.text];
-    else
-      return null;
+    return 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|null}
    */
-  _checkEntryMatch: function(keyword, location, typeMask, docDomain, thirdParty, sitekey, specificOnly)
+  _checkEntryMatch(keyword, location, typeMask, docDomain, thirdParty, sitekey,
+                   specificOnly)
   {
     let list = this.filterByKeyword[keyword];
     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;
     }
     return null;
   },
 
   /**
    * Tests whether the URL matches any of the known filters
-   * @param {String} location URL to be tested
+   * @param {string} location URL to be tested
    * @param {number} typeMask bitmask of content / request types to match
-   * @param {String} docDomain domain name of the document that loads the URL
-   * @param {Boolean} thirdParty should be true if the URL is a third-party request
-   * @param {String} sitekey public key provided by the document
-   * @param {Boolean} specificOnly should be true if generic matches should be ignored
-   * @return {RegExpFilter} matching filter or null
+   * @param {string} docDomain domain name of the document that loads the URL
+   * @param {boolean} thirdParty should be true if the URL is a third-party
+   *                             request
+   * @param {string} sitekey public key provided by the document
+   * @param {boolean} specificOnly should be true if generic matches should be
+   *                               ignored
+   * @return {RegExpFilter|null} matching filter or null
    */
-  matchesAny: function(location, typeMask, docDomain, thirdParty, sitekey, specificOnly)
+  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);
+        let result = this._checkEntryMatch(substr, 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
  */
 function CombinedMatcher()
 {
   this.blacklist = new Matcher();
   this.whitelist = new Matcher();
   this.resultCache = Object.create(null);
 }
 exports.CombinedMatcher = CombinedMatcher;
 
 /**
  * Maximal number of matching cache entries to be kept
- * @type Number
+ * @type {number}
  */
 CombinedMatcher.maxCacheEntries = 1000;
 
 CombinedMatcher.prototype =
 {
   /**
    * Matcher for blocking rules.
-   * @type Matcher
+   * @type {Matcher}
    */
   blacklist: null,
 
   /**
    * Matcher for exception rules.
-   * @type Matcher
+   * @type {Matcher}
    */
   whitelist: null,
 
   /**
    * Lookup table of previous matchesAny results
-   * @type Object
+   * @type {Object}
    */
   resultCache: null,
 
   /**
    * Number of entries in resultCache
-   * @type Number
+   * @type {number}
    */
   cacheEntries: 0,
 
   /**
    * @see Matcher#clear
    */
-  clear: function()
+  clear()
   {
     this.blacklist.clear();
     this.whitelist.clear();
     this.resultCache = Object.create(null);
     this.cacheEntries = 0;
   },
 
   /**
    * @see Matcher#add
+   * @param {Filter} filter
    */
-  add: function(filter)
+  add(filter)
   {
     if (filter instanceof WhitelistFilter)
       this.whitelist.add(filter);
     else
       this.blacklist.add(filter);
 
     if (this.cacheEntries > 0)
     {
       this.resultCache = Object.create(null);
       this.cacheEntries = 0;
     }
   },
 
   /**
    * @see Matcher#remove
+   * @param {Filter} filter
    */
-  remove: function(filter)
+  remove(filter)
   {
     if (filter instanceof WhitelistFilter)
       this.whitelist.remove(filter);
     else
       this.blacklist.remove(filter);
 
     if (this.cacheEntries > 0)
     {
       this.resultCache = Object.create(null);
       this.cacheEntries = 0;
     }
   },
 
   /**
    * @see Matcher#findKeyword
+   * @param {Filter} filter
+   * @return {string} keyword
    */
-  findKeyword: function(filter)
+  findKeyword(filter)
   {
     if (filter instanceof WhitelistFilter)
       return this.whitelist.findKeyword(filter);
-    else
-      return this.blacklist.findKeyword(filter);
+    return this.blacklist.findKeyword(filter);
   },
 
   /**
    * @see Matcher#hasFilter
+   * @param {Filter} filter
+   * @return {boolean}
    */
-  hasFilter: function(filter)
+  hasFilter(filter)
   {
     if (filter instanceof WhitelistFilter)
       return this.whitelist.hasFilter(filter);
-    else
-      return this.blacklist.hasFilter(filter);
+    return this.blacklist.hasFilter(filter);
   },
 
   /**
    * @see Matcher#getKeywordForFilter
+   * @param {Filter} filter
+   * @return {string} keyword
    */
-  getKeywordForFilter: function(filter)
+  getKeywordForFilter(filter)
   {
     if (filter instanceof WhitelistFilter)
       return this.whitelist.getKeywordForFilter(filter);
-    else
-      return this.blacklist.getKeywordForFilter(filter);
+    return this.blacklist.getKeywordForFilter(filter);
   },
 
   /**
    * Checks whether a particular filter is slow
+   * @param {RegExpFilter} filter
+   * @return {boolean}
    */
-  isSlowFilter: function(/**RegExpFilter*/ filter) /**Boolean*/
+  isSlowFilter(filter)
   {
-    let matcher = (filter instanceof WhitelistFilter ? this.whitelist : this.blacklist);
+    let matcher = (
+      filter instanceof WhitelistFilter ? this.whitelist : this.blacklist
+    );
     if (matcher.hasFilter(filter))
       return !matcher.getKeywordForFilter(filter);
-    else
-      return !matcher.findKeyword(filter);
+    return !matcher.findKeyword(filter);
   },
 
   /**
    * Optimized filter matching testing both whitelist and blacklist matchers
    * simultaneously. For parameters see Matcher.matchesAny().
    * @see Matcher#matchesAny
+   * @param {string} location URL to be tested
+   * @param {number} typeMask bitmask of content / request types to match
+   * @param {string} docDomain domain name of the document that loads the URL
+   * @param {boolean} thirdParty should be true if the URL is a third-party
+   *                             request
+   * @param {string} sitekey public key provided by the document
+   * @param {boolean} specificOnly should be true if generic matches should be
+   *                               ignored
+   * @return {RegExpFilter|null} matching filter or null
    */
-  matchesAnyInternal: function(location, typeMask, docDomain, thirdParty, sitekey, specificOnly)
+  matchesAnyInternal(location, typeMask, docDomain, thirdParty, sitekey,
+                     specificOnly)
   {
     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);
+        let result = this.whitelist._checkEntryMatch(
+          substr, location, typeMask, docDomain, thirdParty, sitekey
+        );
         if (result)
           return result;
       }
       if (substr in this.blacklist.filterByKeyword && blacklistHit === null)
-        blacklistHit = this.blacklist._checkEntryMatch(substr, location, typeMask, docDomain, thirdParty, sitekey, specificOnly);
+      {
+        blacklistHit = this.blacklist._checkEntryMatch(
+          substr, location, typeMask, docDomain, thirdParty, sitekey,
+          specificOnly
+        );
+      }
     }
     return blacklistHit;
   },
 
   /**
    * @see Matcher#matchesAny
+   * @param {string} location URL to be tested
+   * @param {number} typeMask bitmask of content / request types to match
+   * @param {string} docDomain domain name of the document that loads the URL
+   * @param {boolean} thirdParty should be true if the URL is a third-party
+   *                             request
+   * @param {string} sitekey public key provided by the document
+   * @param {boolean} specificOnly should be true if generic matches should be
+   *                               ignored
+   * @return {RegExpFilter} matching filter or null
    */
-  matchesAny: function(location, typeMask, docDomain, thirdParty, sitekey, specificOnly)
+  matchesAny(location, typeMask, docDomain, thirdParty, sitekey, specificOnly)
   {
-    let key = location + " " + typeMask + " " + docDomain + " " + thirdParty + " " + sitekey + " " + specificOnly;
+    let key = location + " " + typeMask + " " + docDomain + " " + thirdParty +
+      " " + sitekey + " " + specificOnly;
     if (key in this.resultCache)
       return this.resultCache[key];
 
-    let result = this.matchesAnyInternal(location, typeMask, docDomain, thirdParty, sitekey, specificOnly);
+    let result = this.matchesAnyInternal(location, typeMask, docDomain,
+                                         thirdParty, sitekey, specificOnly);
 
     if (this.cacheEntries >= CombinedMatcher.maxCacheEntries)
     {
       this.resultCache = Object.create(null);
       this.cacheEntries = 0;
     }
 
     this.resultCache[key] = result;
     this.cacheEntries++;
 
     return result;
   }
-}
+};
 
 /**
  * Shared CombinedMatcher instance that should usually be used.
- * @type CombinedMatcher
+ * @type {CombinedMatcher}
  */
 let defaultMatcher = exports.defaultMatcher = new CombinedMatcher();