Issue 4579 - Promisify APIs

polyfill.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";
 
-(function()

[Manish Jethani, 2017/10/17 13:33:24]

This all needs to be wrapped inside an anonymous function here so we don't
pollute the global namespace.

[Manish Jethani, 2017/10/17 17:35:45]

Actually this can just be an anonymous block.

Done.

[kzar, 2017/10/17 18:13:42]

IIRC Firefox got upset when declaring functions inside of a block like that.

[Manish Jethani, 2017/10/17 20:48:45]

You're right, the function declarations would be "hoisted" to the outer scope
here.

Fixed, by using arrow functions.

[Sebastian Noack, 2017/10/17 23:31:03]

Both of you are wrong. In strict mode, as of ES2015, and FF47+, function
declarations are scoped to the surrounding block. Hence declaring named
functions is totally fine, and IMO preferable, here.

However, what Dave is talking about is; before ES2015, function declarations
in nested blocks were non-standard, and the behavior varied across JavaScript
implementations, e.g. Firefox <47 threw an error.

[Manish Jethani, 2017/10/18 00:05:33]

Ah, of course.

Reverted.

 {
   const asyncAPIs = [
     "contextMenus.removeAll",
     "devtools.panels.create",
     "notifications.clear",
     "notifications.create",
     "runtime.openOptionsPage",
     "runtime.sendMessage",
     "runtime.setUninstallURL",
     "storage.local.get",
     "storage.local.remove",
     "storage.local.set",
     "storage.managed.get",
     "tabs.create",
     "tabs.get",
     "tabs.insertCSS",
     "tabs.query",
     "tabs.reload",
     "tabs.sendMessage",
     "tabs.update",
     "webNavigation.getAllFrames",
     "webRequest.handlerBehaviorChanged",
     "windows.create",
     "windows.update"
   ];
 
   function wrapAPI(api)
   {
     let object = browser;

[Manish Jethani, 2017/10/17 13:33:23]

Note: Using browser now instead of chrome

     let path = api.split(".");
     let name = path.pop();
 
     for (let node of path)
     {
       object = object[node];
 
       if (!object)
         return;
     }
@@ skipping 29 matching lines @@
   function shouldWrapAPIs()
   {
     try
     {
       return !(browser.storage.local.get([]) instanceof Promise);
     }
     catch (error)
     {
     }
 
     return true;

[Wladimir Palant, 2017/10/18 08:59:11]

Nit: I would put that return inside the catch block which makes the logic
clearer IMHO.

[Manish Jethani, 2017/10/18 11:00:26]

Acknowledged.

   }
 
   if (shouldWrapAPIs())
   {
     // Unlike Firefox and Microsoft Edge, Chrome doesn't have a "browser" object,

[Manish Jethani, 2017/10/17 13:33:23]

After calling shouldWrapAPIs we can safely overwrite window.browser 

     // but provides the extension API through the "chrome" namespace
     // (non-standard).
     if (typeof browser == "undefined")
       window.browser = chrome;
 
     for (let api of asyncAPIs)
       wrapAPI(api);
   }
 
   // Workaround since HTMLCollection, NodeList, StyleSheetList, and CSSRuleList
   // didn't have iterator support before Chrome 51.
   // https://bugs.chromium.org/p/chromium/issues/detail?id=401699
   for (let object of [HTMLCollection, NodeList, StyleSheetList, CSSRuleList])
   {
     if (!(Symbol.iterator in object.prototype))
       object.prototype[Symbol.iterator] = Array.prototype[Symbol.iterator];
   }
-}());
+}