Issue 7232 - Move third-party request check into adblockpluscore

lib/domain.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";
 
 const publicSuffixes = require("../data/publicSuffixList.json");
 
 /**
+ * Checks whether the given hostname is a domain.
+ *
+ * @param {string} hostname
+ * @returns {boolean}
+ */
+function isDomain(hostname)
+{
+  // 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;
+}
+
+/**
  * Gets the base domain for the given hostname.
  *
  * @param {string} hostname
  * @returns {string}
  */
-exports.getDomain = hostname =>
+function getDomain(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 a request's origin is different from its document's origin.
+ *
+ * @param {URL} url The request URL.
+ * @param {string} documentHostname The IDNA-encoded hostname of the document.
+ *
+ * @returns {boolean}
+ */
+function isThirdParty(url, documentHostname)
+{
+  let requestHostname = url.hostname.replace(/\.+$/, "");
+  documentHostname = documentHostname.replace(/\.+$/, "");
+
+  if (requestHostname == documentHostname)
+    return false;
+
+  if (!isDomain(requestHostname) || !isDomain(documentHostname))
+    return true;
+
+  return getDomain(requestHostname) != getDomain(documentHostname);
+}
+
+exports.isThirdParty = isThirdParty;