Issue 4721 - Use IndexedDB for storage in Edge

lib/io.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
  * 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/>.
  */
 
-var keyPrefix = "file:";
+const keyPrefix = "file:";
 
 function fileToKey(file)
 {
   return keyPrefix + (file instanceof FakeFile ? file.path : file.spec);
 }
 
 function loadFile(file, successCallback, errorCallback)
 {
-  var key = fileToKey(file);

[kzar, 2016/12/16 13:22:25]

Any reason you've changed `let` and `const` to `var` in the file?

[Oleksandr, 2016/12/19 11:03:14]

Done.

-  // Make sure we do not have subscriptions in localStorage from older versions first

[kzar, 2016/12/16 13:22:25]

Nit: This comment is too long, mind wrapping the line?

[Oleksandr, 2016/12/19 11:03:14]

Done.

-  var entry = localStorage.getItem(key);
+  let key = fileToKey(file);
+
+  // Make sure we do not have subscriptions in localStorage from older
+  // versions first
+  let entry = localStorage.getItem(key);
   if (typeof entry == "string")
   {
     try
     {
       entry = JSON.parse(entry);
     }
     catch(err) 
     {
       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"));                
+      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: Array.from(data)

[Oleksandr, 2016/12/14 01:55:55]

Note: While the rest of this code is exactly the same as in
https://hg.adblockplus.org/adblockplusedgems/rev/5a8b109447d3, this line was
adapted to a recent change in adblockpluschrome.

+    content: Array.from(data),
+    lastModified: Date.now()
   };
 
   localStorage.removeItem(key);
   localforage.setItem(key, entry, callback);
 }
-exports.IO = {
+
+exports.IO =
+{
   resolveFilePath: function(path)
   {
     return new FakeFile(path);
   },
+
   readFromFile: function(file, listener, callback)
   {
     function onLoaded(entry)
     {
       if ("content" in entry)
       {
-        for (var _loopIndex15 = 0; _loopIndex15 < entry.content.length; ++_loopIndex15)

[kzar, 2016/12/16 13:22:25]

What's the point of this change to the loop? Seems like the old code would do
the same thing if you just added the `if ("content" in entry)` check.

[Oleksandr, 2016/12/19 11:03:14]

Done.

-        {
-          var line = entry.content[_loopIndex15];
+        for (let line of entry.content)
           listener.process(line);
-        }
       }
       listener.process(null);
       callback(null);
     }
+
     loadFile(file, onLoaded, callback);
   },
+
   writeToFile: function(file, data, callback)
   {
     saveFile(file, data, callback);
   },
+
   copyFile: function(fromFile, toFile, callback)
   {
     function onLoaded(entry)
     {
       saveFile(toFile, entry.content, callback);
     }
-    loadFile(file, onLoaded, callback);
+
+    loadFile(fromFile, onLoaded, callback);
   },
+
   renameFile: function(fromFile, newName, callback)
   {
     function onLoaded()
     {
       ext.storage.remove(fileToKey(fromFile), function()
       {
         ext.storage.set(keyPrefix + newName, entry, callback);
       });
     }
-    loadFile(file, onLoaded, callback);
+
+    loadFile(fromFile, onLoaded, callback);
   },
+
   removeFile: function(file, callback)
   {
     ext.storage.remove(fileToKey(file), callback);
   },
+
   statFile: function(file, callback)
   {
     function onLoaded(entry)
     {
-      callback(null,
-      {
+      callback(null, {
         exists: true,
         lastModified: entry.lastModified
       });
     }
+
     loadFile(file, onLoaded, callback);
   }
 };