Issue 6741 - Use ES2015 classes in lib/matcher.js

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
  * 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.
  */
 
 const {Filter, WhitelistFilter} = require("./filterClasses");
 
 /**
  * Blacklist/whitelist filter matching
- * @constructor
  */
-function Matcher()
+class Matcher
 {
-  this.clear();
-}
-exports.Matcher = Matcher;
+  constructor()
+  {
+    /**
+     * Lookup table for filters by their associated keyword
+     * @type {Map.<string,(Filter|Filter[])>}
+     */
+    this.filterByKeyword = new Map();
 
-Matcher.prototype = {
-  /**
-   * Lookup table for filters by their associated keyword
-   * @type {Map.<string,(Filter|Filter[])>}
-   */
-  filterByKeyword: null,
-
-  /**
-   * Lookup table for keywords by the filter
-   * @type {Map.<Filter,string>}
-   */
-  keywordByFilter: null,
+    /**
+     * Lookup table for keywords by the filter
+     * @type {Map.<Filter,string>}
+     */
+    this.keywordByFilter = new Map();
+  }
 
   /**
    * Removes all known filters
    */
   clear()
   {
-    this.filterByKeyword = new Map();
-    this.keywordByFilter = new Map();
-  },
+    this.filterByKeyword.clear();
+    this.keywordByFilter.clear();
+  }
 
   /**
    * Adds a filter to the matcher
    * @param {RegExpFilter} filter
    */
   add(filter)
   {
     if (this.keywordByFilter.has(filter))
       return;
 
     // Look for a suitable keyword
     let keyword = this.findKeyword(filter);
     let oldEntry = this.filterByKeyword.get(keyword);
     if (typeof oldEntry == "undefined")
       this.filterByKeyword.set(keyword, filter);
     else if (oldEntry.length == 1)
       this.filterByKeyword.set(keyword, [oldEntry, filter]);
     else
       oldEntry.push(filter);
     this.keywordByFilter.set(filter, keyword);
-  },
+  }
 
   /**
    * Removes a filter from the matcher
    * @param {RegExpFilter} filter
    */
   remove(filter)
   {
     let keyword = this.keywordByFilter.get(filter);
     if (typeof keyword == "undefined")
       return;
 
     let list = this.filterByKeyword.get(keyword);
     if (list.length <= 1)
       this.filterByKeyword.delete(keyword);
     else
     {
       let index = list.indexOf(filter);
       if (index >= 0)
       {
         list.splice(index, 1);
         if (list.length == 1)
           this.filterByKeyword.set(keyword, list[0]);
       }
     }
 
     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
+   * @returns {string} keyword or an empty string if no keyword could be found
    */
   findKeyword(filter)
   {
     let result = "";
     let {text} = filter;
     if (Filter.regexpRegExp.test(text))
       return result;
 
     // Remove options
     let match = Filter.optionsRegExp.exec(text);
@@ skipping 20 matching lines @@
       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}
+   * @returns {boolean}
    */
   hasFilter(filter)
   {
     return this.keywordByFilter.has(filter);
-  },
+  }
 
   /**
    * Returns the keyword used for a filter, null for unknown filters.

[Manish Jethani, 2018/09/03 18:46:49]

Let's make this `<code>null</code>` as well while we're at it.

[Jon Sonesen, 2018/09/05 14:05:27]

Done.

    * @param {RegExpFilter} filter
-   * @return {?string}
+   * @returns {?string}
    */
   getKeywordForFilter(filter)
   {
     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}
+   * @param {string} [docDomain]
+   * @param {boolean} [thirdParty]
+   * @param {string} [sitekey]
+   * @param {boolean} [specificOnly]
+   * @returns {?Filter}
    */
   _checkEntryMatch(keyword, location, typeMask, docDomain, thirdParty, sitekey,
                    specificOnly)
   {
     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;
     }
     return null;
-  },
+  }
 
   /**
    * Tests whether the URL matches any of the known filters
    * @param {string} location
    *   URL to be tested
    * @param {number} typeMask
    *   bitmask of content / request types to match
-   * @param {string} docDomain
+   * @param {string} [docDomain]
    *   domain name of the document that loads the URL
-   * @param {boolean} thirdParty
+   * @param {boolean} [thirdParty]
    *   should be true if the URL is a third-party request
-   * @param {string} sitekey
+   * @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 {boolean} [specificOnly]
+   *   should be <code>true</code> if generic matches should be ignored
+   * @returns {?RegExpFilter}
+   *   matching filter or <code>null</code>
    */
   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 result = this._checkEntryMatch(candidates[i], location, typeMask,
                                          docDomain, thirdParty, sitekey,
                                          specificOnly);
       if (result)
         return result;
     }
 
     return null;
   }
-};
+}
+
+exports.Matcher = Matcher;
+
 
 /**
  * Combines a matcher for blocking and exception rules, automatically sorts
- * rules into two Matcher instances.
- * @constructor
- * @augments Matcher
+ * rules into two {@link Matcher} instances.
  */
-function CombinedMatcher()
+class CombinedMatcher
 {
-  this.blacklist = new Matcher();
-  this.whitelist = new Matcher();
-  this.resultCache = new Map();
-}
-exports.CombinedMatcher = CombinedMatcher;
+  constructor()
+  {
+    /**
+     * Maximal number of matching cache entries to be kept
+     * @type {number}
+     */
+    this.maxCacheEntries = 1000;
 
-/**
- * Maximal number of matching cache entries to be kept
- * @type {number}
- */
-CombinedMatcher.maxCacheEntries = 1000;
+    /**
+     * Matcher for blocking rules.
+     * @type {Matcher}
+     */
+    this.blacklist = new Matcher();
 
-CombinedMatcher.prototype =
-{
-  /**
-   * Matcher for blocking rules.
-   * @type {Matcher}
-   */
-  blacklist: null,
+    /**
+     * Matcher for exception rules.
+     * @type {Matcher}
+     */
+    this.whitelist = new Matcher();
 
-  /**
-   * Matcher for exception rules.
-   * @type {Matcher}
-   */
-  whitelist: null,
-
-  /**
-   * Lookup table of previous matchesAny results
-   * @type {Map.<string,Filter>}
-   */
-  resultCache: null,
+    /**
+     * Lookup table of previous {@link Matcher#matchesAny} results
+     * @type {Map.<string,Filter>}
+     */
+    this.resultCache = new Map();
+  }
 
   /**
    * @see Matcher#clear
    */
   clear()
   {
     this.blacklist.clear();
     this.whitelist.clear();
     this.resultCache.clear();
-  },
+  }
 
   /**
    * @see Matcher#add
    * @param {Filter} filter

[Manish Jethani, 2018/09/03 18:46:49]

When we use @see, we're not being consistent in adding @param tags. Here we're
adding them, but not for matchesAny for example. Let's just leave the @param
tags out here when using @see.

Also see my comment about using @implements in the long run.

[Jon Sonesen, 2018/09/05 14:05:27]

The reason for this is that matchesAny does not have a filter parameter, so
removing the @param tag causes eslint to complain since the definitions don't
match.

[Manish Jethani, 2018/09/05 19:33:57]

Oh damn. OK, no problem then.

    */
   add(filter)
   {
     if (filter instanceof WhitelistFilter)
       this.whitelist.add(filter);
     else
       this.blacklist.add(filter);
 
     this.resultCache.clear();
-  },
+  }
 
   /**
    * @see Matcher#remove
    * @param {Filter} filter
    */
   remove(filter)
   {
     if (filter instanceof WhitelistFilter)
       this.whitelist.remove(filter);
     else
       this.blacklist.remove(filter);
 
     this.resultCache.clear();
-  },
+  }
 
   /**
    * @see Matcher#findKeyword
    * @param {Filter} filter
-   * @return {string} keyword
+   * @returns {string} keyword
    */
   findKeyword(filter)
   {
     if (filter instanceof WhitelistFilter)
       return this.whitelist.findKeyword(filter);
     return this.blacklist.findKeyword(filter);
-  },
+  }
 
   /**
    * @see Matcher#hasFilter
    * @param {Filter} filter
-   * @return {boolean}
+   * @returns {boolean}
    */
   hasFilter(filter)
   {
     if (filter instanceof WhitelistFilter)
       return this.whitelist.hasFilter(filter);
     return this.blacklist.hasFilter(filter);
-  },
+  }
 
   /**
    * @see Matcher#getKeywordForFilter
    * @param {Filter} filter
-   * @return {string} keyword
+   * @returns {string} keyword
    */
   getKeywordForFilter(filter)
   {
     if (filter instanceof WhitelistFilter)
       return this.whitelist.getKeywordForFilter(filter);
     return this.blacklist.getKeywordForFilter(filter);
-  },
+  }
 
   /**
    * Checks whether a particular filter is slow
    * @param {RegExpFilter} filter
-   * @return {boolean}
+   * @returns {boolean}
    */
   isSlowFilter(filter)
   {
     let matcher = (
       filter instanceof WhitelistFilter ? this.whitelist : this.blacklist
     );
     if (matcher.hasFilter(filter))
       return !matcher.getKeywordForFilter(filter);
     return !matcher.findKeyword(filter);
-  },
+  }
 
   /**
    * Optimized filter matching testing both whitelist and blacklist matchers
    * simultaneously. For parameters see
      {@link Matcher#matchesAny Matcher.matchesAny()}.
    * @see Matcher#matchesAny
    * @inheritdoc

[Manish Jethani, 2018/09/03 18:46:49]

I don't think @inheritdoc makes sense here (also below), because CombinedMatches
does not in fact extend Matcher. It does nothing for the generated
documentation.

In the long run we should probably consider adding a Matcher interface and the
use @implements [1] to automatically inherit the documentation, but this would
be separate thing.

[1]: http://usejsdoc.org/tags-implements.html

[Jon Sonesen, 2018/09/05 14:05:27]

Similarly to above, eslint complains here without @inherit doc

    */
   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];
       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;
-  },
+  }
 
   /**
    * @see Matcher#matchesAny
    * @inheritdoc
    */
   matchesAny(location, typeMask, docDomain, thirdParty, sitekey, specificOnly)
   {
     let key = location + " " + typeMask + " " + docDomain + " " + thirdParty +
       " " + sitekey + " " + specificOnly;
 
     let result = this.resultCache.get(key);
     if (typeof result != "undefined")
       return result;
 
     result = this.matchesAnyInternal(location, typeMask, docDomain,
                                      thirdParty, sitekey, specificOnly);
 
     if (this.resultCache.size >= CombinedMatcher.maxCacheEntries)
       this.resultCache.clear();
 
     this.resultCache.set(key, result);
 
     return result;
   }
-};
+}
+
+exports.CombinedMatcher = CombinedMatcher;
 
 /**
- * Shared CombinedMatcher instance that should usually be used.
+ * Shared {@link CombinedMatcher} instance that should usually be used.
  * @type {CombinedMatcher}
  */
 exports.defaultMatcher = new CombinedMatcher();

[Manish Jethani, 2018/09/03 18:46:49]

I think we should follow the convention of first declaring something and then
exporting it. We're doing this at the end of lib/filterListener.js now.

  let defaultMatcher = new CombinedMatcher();

  exports.defaultMatcher = defaultMatcher;

[Jon Sonesen, 2018/09/05 14:05:27]

Done.