Issue 5161 - Use maps and sets where appropriate

lib/popupBlocker.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2017 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/>.
  */
 
 /** @module popupBlocker */
 
 "use strict";
 
 const {defaultMatcher} = require("matcher");
 const {BlockingFilter, RegExpFilter} = require("filterClasses");
 const {stringifyURL, isThirdParty, extractHostFromFrame} = require("url");
 const {checkWhitelisted} = require("whitelisting");
 const {logRequest} = require("devtools");
 
-let loadingPopups = Object.create(null);
-
-function hasLoadingPopups()
-{
-  return Object.keys(loadingPopups).length > 0;
-}
+let loadingPopups = new Map();
 
 function forgetPopup(tabId)
 {
-  delete loadingPopups[tabId];
+  loadingPopups.delete(tabId);
 
-  if (!hasLoadingPopups())
+  if (loadingPopups.size == 0)
   {
     chrome.webRequest.onBeforeRequest.removeListener(onPopupURLChanged);
     chrome.webNavigation.onCommitted.removeListener(onPopupURLChanged);
     chrome.webNavigation.onCompleted.removeListener(onCompleted);
     chrome.tabs.onRemoved.removeListener(forgetPopup);
   }
 }
 
 function checkPotentialPopup(tabId, popup)
 {
@@ skipping 21 matching lines @@
     specificOnly, filter
   );
 }
 
 function onPopupURLChanged(details)
 {
   // Ignore frames inside the popup window.
   if (details.frameId != 0)
     return;
 
-  let popup = loadingPopups[details.tabId];
+  let popup = loadingPopups.get(details.tabId);
   if (popup)
   {
     popup.url = details.url;
     if (popup.sourceFrame)
       checkPotentialPopup(details.tabId, popup);
   }
 }
 
 function onCompleted(details)
 {
   if (details.frameId == 0 && details.url != "about:blank")
     forgetPopup(details.tabId);
 }
 
 chrome.webNavigation.onCreatedNavigationTarget.addListener(details =>
 {
-  if (!hasLoadingPopups())
+  if (loadingPopups.size == 0)
   {
     chrome.webRequest.onBeforeRequest.addListener(
       onPopupURLChanged,
       {
         urls: ["<all_urls>"],
         types: ["main_frame"]
       }
     );
     chrome.webNavigation.onCommitted.addListener(onPopupURLChanged);
     chrome.webNavigation.onCompleted.addListener(onCompleted);
     chrome.tabs.onRemoved.addListener(forgetPopup);
   }
 
   let {tabId} = details;
-  let popup = loadingPopups[tabId] = {
+
+  let popup = {
     url: details.url,
     sourcePage: new ext.Page({id: details.sourceTabId}),
     sourceFrame: null
   };
+
+  loadingPopups.set(tabId, popup);
+
   let frame = ext.getFrame(details.sourceTabId, details.sourceFrameId);
 
   if (checkWhitelisted(popup.sourcePage, frame))
   {
     forgetPopup(tabId);
   }
   else
   {
     popup.sourceFrame = frame;
     checkPotentialPopup(tabId, popup);
   }
 });