Issue 4023 - Use localforage (IndexedDB) instead of localStorage

lib/adblockplus.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 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 342 matching lines @@
   var keyPrefix = "file:";
 
   function fileToKey(file)
   {
     return keyPrefix + (file instanceof FakeFile ? file.path : file.spec);
   }
 
   function loadFile(file, successCallback, errorCallback)
   {
     var key = fileToKey(file);
+    // Make sure we do not have subscriptions in localStorage from older versions first
     var entry = localStorage.getItem(key);
-    if (entry)
+    if (typeof entry == "string")
     {
       try
       {
-        setTimeout(successCallback(JSON.parse(entry)), 0);

[Sebastian Noack, 2016/10/06 23:38:35]

Not too important but you can call setTimout() without secomd parameter. That is
equivalent to passing 0. Not sure if it is worth catching that theoretical error
in the first place.

[Oleksandr, 2016/10/07 16:29:17]

Done. But I think it wouldn't hurt catching an error here. I stumbled across
this when I tried my synthetic test of upgrade. Who knows what can be found in
localStorage, really... Users can edit it manually too, in theory.

[kzar, 2016/10/07 17:00:00]

Wouldn't this also catch an exception thrown by the successCallback function,
resulting in both successCallback and errorCallback to be called?

[Oleksandr, 2016/10/07 17:21:06]

Yes, but I think that's expected, no?

+        entry = JSON.parse(entry);
       }
       catch(err) 
       {
-        setTimeout(errorCallback(new Error("File is corrupted")), 0);
-      }
-    }
-    else
-    {
-      localforage.getItem(key, function(err, value) 
-      {
-        if (err || !value)
-          errorCallback(new Error("File doesn't exist"));                
-        else
-          successCallback(value);
-      });
-    }
+        setTimeout(errorCallback(new Error("File is corrupted")));
+        return;
+      }
+      setTimeout(successCallback(entry));
+      return;
+    }
+    // Now try to read from IndexedDB
+    localforage.getItem(key, function(err, value) 
+    {
+      if (err || !value)
+        errorCallback(new Error("File doesn't exist"));                
+      else
+        successCallback(value);
+    });
   }
 
   function saveFile(file, data, callback)
   {
     var key = fileToKey(file);
     var entry = {
       lastModified: Date.now(),
       content: data
     };
 
@@ skipping 6160 matching lines @@
     search.push("notificationDownloadCount=" + encodeURIComponent(downlCount));
     chrome.runtime.setUninstallURL(Utils.getDocLink("uninstalled") + "&" + search.join("&"));
   }
   if ("setUninstallURL" in chrome.runtime)
   {
     Prefs.untilLoaded.then(setUninstallURL);
     Prefs.on("notificationdata", setUninstallURL);
   }
   return exports;
 })();