Issue 7285 - Abstract caching logic

lib/matcher.js

Index: lib/matcher.js
===================================================================
--- a/lib/matcher.js
+++ b/lib/matcher.js
@@ -19,16 +19,17 @@
 
 /**
  * @fileOverview Matcher class implementing matching addresses against
  *               a list of filters.
  */
 
 const {RegExpFilter, WhitelistFilter} = require("./filterClasses");
 const {normalizeHostname, suffixes} = require("./domain");
+const {Cache} = require("./caching");
 
 /**
  * Regular expression for matching a keyword in a filter.
  * @type {RegExp}
  */
 const keywordRegExp = /[^a-z0-9%*][a-z0-9%]{3,}(?=[^a-z0-9%*])/;
 
 /**
@@ -619,41 +620,35 @@
  * Combines a matcher for blocking and exception rules, automatically sorts
  * rules into two {@link Matcher} instances.
  */
 class CombinedMatcher
 {
   constructor()
   {
     /**
-     * Maximal number of matching cache entries to be kept
-     * @type {number}
-     */
-    this.maxCacheEntries = 10000;
-
-    /**
      * Matcher for blocking rules.
      * @type {Matcher}
      * @private
      */
     this._blacklist = new Matcher();
 
     /**
      * Matcher for exception rules.
      * @type {Matcher}
      * @private
      */
     this._whitelist = new Matcher();
 
     /**
      * Lookup table of previous {@link Matcher#matchesAny} results
-     * @type {Map.<string,Filter>}
+     * @type {Cache.<string, ?Filter>}
      * @private
      */
-    this._resultCache = new Map();
+    this._resultCache = new Cache(10000);
   }
 
   /**
    * @see Matcher#clear
    */
   clear()
   {
     this._blacklist.clear();
@@ -803,28 +798,25 @@
 
   /**
    * @see Matcher#matchesAny
    * @inheritdoc
    */
   matchesAny(location, typeMask, docDomain, thirdParty, sitekey, specificOnly)
   {
     let key = location + " " + typeMask + " " + docDomain + " " + thirdParty +
-      " " + sitekey + " " + specificOnly;
+              " " + 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 >= this.maxCacheEntries)
-      this._resultCache.clear();
-
     this._resultCache.set(key, result);
 
     return result;
   }
 
   /**
    * @typedef {object} MatcherSearchResults
    * @property {Array.<BlockingFilter>} [blocking] List of blocking filters
@@ -858,19 +850,16 @@
 
     let result = this._resultCache.get(key);
     if (typeof result != "undefined")
       return result;
 
     result = this._searchInternal(location, typeMask, docDomain, thirdParty,
                                   sitekey, specificOnly, filterType);
 
-    if (this._resultCache.size >= this.maxCacheEntries)
-      this._resultCache.clear();
-
     this._resultCache.set(key, result);
 
     return result;
   }
 
   /**
    * Tests whether the URL is whitelisted
    * @see Matcher#matchesAny