Issue 1273 - Worked around WebKit getter misoptimization on Safari 8

lib/filterClasses.js

 /*
  * This file is part of Adblock Plus <http://adblockplus.org/>,
  * Copyright (C) 2006-2014 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 306 matching lines @@
    * @type Boolean
    */
   domainSourceIsUpperCase: false,
 
   /**
    * Map containing domains that this filter should match on/not match on or null if the filter should match on all domains
    * @type Object
    */
   get domains()
   {
+    // Despite this property being cached, the getter is called
+    // several times on Safari, due to WebKit bug 132872
+    let prop = Object.getOwnPropertyDescriptor(this, "domains");
+    if (prop)
+      return prop.value;
+
     let domains = null;
 
     if (this.domainSource)
     {
       let source = this.domainSource;
       if (!this.domainSourceIsUpperCase) {
         // RegExpFilter already have uppercase domains
         source = source.toUpperCase();
       }
       let list = source.split(this.domainSeparator);
@@ skipping 170 matching lines @@
    * Expression from which a regular expression should be generated - for delayed creation of the regexp property
    * @type String
    */
   regexpSource: null,
   /**
    * Regular expression to be used when testing against this filter
    * @type RegExp
    */
   get regexp()
   {
+    // Despite this property being cached, the getter is called
+    // several times on Safari, due to WebKit bug 132872
+    let prop = Object.getOwnPropertyDescriptor(this, "regexp");
+    if (prop)
+      return prop.value;
+
     // Remove multiple wildcards
     let source = this.regexpSource
       .replace(/\*+/g, "*")        // remove multiple wildcards
       .replace(/\^\|$/, "^")       // remove anchors following separator placeholder
       .replace(/\W/g, "\\$&")      // escape special symbols
       .replace(/\\\*/g, ".*")      // replace wildcards by .*
       // process separator placeholders (all ANSI characters but alphanumeric characters and _%.-)
       .replace(/\\\^/g, "(?:[\\x00-\\x24\\x26-\\x2C\\x2F\\x3A-\\x40\\x5B-\\x5E\\x60\\x7B-\\x7F]|$)")
       .replace(/^\\\|\\\|/, "^[\\w\\-]+:\\/+(?!\\/)(?:[^\\/]+\\.)?") // process extended anchor at expression start
       .replace(/^\\\|/, "^")       // process anchor at expression start
@@ skipping 363 matching lines @@
 function ElemHideException(text, domains, selector)
 {
   ElemHideBase.call(this, text, domains, selector);
 }
 exports.ElemHideException = ElemHideException;
 
 ElemHideException.prototype =
 {
   __proto__: ElemHideBase.prototype
 };