Issue 6477 - separate done and error callbacks in IFileSystem::Read

lib/prefs.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
@@ skipping 66 matching lines @@
 
         for (let listener of listeners)
           listener(key);
       },
       enumerable: true
     });
 }
 
 function load()
 {
-  _fileSystem.read(prefsFileName, result =>
+  new Promise((resolve, reject) =>
   {
-    // prefs.json is expected to be missing, ignore errors reading file
-    if (!result.error)
+    _fileSystem.read(prefsFileName, resolve, reject);
+  }).then((result) =>
+  {
+    try
     {
-      try
-      {
-        let data = JSON.parse(result.content);
-        for (let key in data)
-          if (key in defaults)
-            values[key] = data[key];
-      }
-      catch (e)
-      {
-        Cu.reportError(e);
-      }
+      let data = JSON.parse(result.content);
+      for (let key in data)
+        if (key in defaults)
+          values[key] = data[key];
     }
-
+    catch (e)
+    {
+      Cu.reportError(e);
+    }
+  }).catch(() =>
+  {
+    // prefs.json is expected to be missing, ignore file reading errors
+  }).then(() =>
+  {
     Prefs.initialized = true;
     if (typeof Prefs._initListener == "function")
       Prefs._initListener();
   });
 }
 
 function save()
 {
   if (isSaving)
   {
@@ skipping 34 matching lines @@
     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();