Issue 3671 - Expose getBaseDomain for abp2blocklist

lib/url.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
@@ skipping 74 matching lines @@
 {
   // No hostname or IPv4 address, also considering hexadecimal octets.
   if (/^((0x[\da-f]+|\d+)(\.|$))*$/i.test(hostname))
     return false;
 
   // IPv6 address. Since there can't be colons in domains, we can
   // just check whether there are any colons to exclude IPv6 addresses.
   return hostname.indexOf(":") == -1;
 }
 
-function getBaseDomain(hostname)
+let getBaseDomain =
+/**
+ * Returns the base domain for the given hostname.
+ *
+ * @param {string}   hostname
+ * @return {string}  base domain
+ */
+exports.getBaseDomain = function(hostname)
 {
   let bits = hostname.split(".");
   let cutoff = bits.length - 2;
 
   for (let i = 0; i < bits.length; i++)
   {
     let offset = publicSuffixes[bits.slice(i).join(".")];
 
     if (typeof offset != "undefined")
     {
       cutoff = i - offset;
       break;
     }
   }
 
   if (cutoff <= 0)
     return hostname;
 
   return bits.slice(cutoff).join(".");
-}
+};
 
 /**
  * Checks whether the request's origin is different from the document's origin.
  *
  * @param {URL}    url           The request URL
  * @param {string} documentHost  The IDN-decoded hostname of the document
  * @return {Boolean}
  */
 exports.isThirdParty = function(url, documentHost)
 {
   let requestHost = getDecodedHostname(url).replace(/\.+$/, "");
   documentHost = documentHost.replace(/\.+$/, "");
 
   if (requestHost == documentHost)
     return false;
 
   if (!isDomain(requestHost) || !isDomain(documentHost))
     return true;
 
   return getBaseDomain(requestHost) != getBaseDomain(documentHost);
 };