Issue 5183 - Provide async interface for FileSystem

lib/prefs.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
@@ skipping 83 matching lines @@
         for (let key in data)
           if (key in defaults)
             values[key] = data[key];
       }
       catch (e)
       {
         Cu.reportError(e);
       }
     }
 
+    Prefs.initialized = true;
     if (typeof Prefs._initListener == "function")
       Prefs._initListener();
   });
 }
 
 function save()
 {
   if (isSaving)
   {
     isDirty = true;
     return;
   }
 
   isDirty = false;
   isSaving = true;
   _fileSystem.write(path, JSON.stringify(values), function()
   {
     isSaving = false;
     if (isDirty)
       save();
   });
 }
 
 let Prefs = exports.Prefs = {
+  initialized: false,
+
   addListener: function(listener)
   {
     if (listeners.indexOf(listener) < 0)
       listeners.push(listener);
   },
 
   removeListener: function(listener)
   {
     let index = listeners.indexOf(listener);
     if (index >= 0)
       listeners.splice(index, 1);
   },
 };
 
 // Update the default prefs with what was preconfigured
 for (let key in _preconfiguredPrefs)
   if (preconfigurable.indexOf(key) != -1)
     defaults[key] = _preconfiguredPrefs[key];
 
 // Define defaults
 for (let key in defaults)
   defineProperty(key);
 
 // Set values of prefs based on defaults
 values = Object.create(defaults);
 
 load();