Issue 4023 - Use localforage (IndexedDB) instead of localStorage

lib/adblockplus.js

Index: lib/adblockplus.js
===================================================================
--- a/lib/adblockplus.js
+++ b/lib/adblockplus.js
@@ -357,60 +357,36 @@
     return keyPrefix + (file instanceof FakeFile ? file.path : file.spec);
   }
 
-  function loadFile(file)
-  {
-    return new Promise(function(resolve, reject)
-    {
-      var key = fileToKey(file);
-      ext.storage.get([key], function(items)
-      {
-        var entry = items[key];
-        if (!entry)
-        {
-          try
-          {
-            entry = JSON.parse(window.localStorage.getItem(key));
-          }
-          catch (err)
-          {}
-        }
-        if (entry)
-        {
-          resolve(entry);
-        }
+  function loadFile(file, successCallback, errorCallback)
+  {
+    var key = fileToKey(file);
+    var entry = localStorage.getItem(key);
+    if (entry)
+    {
+      successCallback(JSON.parse(entry));

[Sebastian Noack, 2016/10/06 12:07:36]

Don't we have to respond asynchronously here (i.e. wrap it by setTimeout)?

[Oleksandr, 2016/10/06 23:28:13]

Indeed, we should. Great catch! For reference, this is discussed here:
https://codereview.adblockplus.org/29348698/diff/29348738/lib/adblockplus.js#....
I wasn't able to test the full upgrade, but a synthetic test did show that this
has to return asynchronously.

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

Yes, that is what I remember, and why I brought it up here.

+    }
+    else
+    {
+      entry = localforage.getItem(key, function(err, value) 

[Sebastian Noack, 2016/10/06 12:07:36]

It seems unnecessary to assign to "entry" here. It seems unused.

[Oleksandr, 2016/10/06 23:28:13]

Done.

+      {
+        if (err || !value)
+          errorCallback(new Error("File doesn't exist"));                
         else
-        {
-          reject(new Error("File doesn't exist"));
-        }
+          successCallback(value);
       });
-    }.bind(this));
+    }
   }
+
   function saveFile(file, data, callback)
   {
-    var entry = {};
     var key = fileToKey(file);
+    var entry = {
+      lastModified: Date.now(),
+      content: data
+    };
 
-    if (typeof browser == "undefined")
-    {
-      entry[key] = {
-        lastModified: Date.now(),
-        content: data
-      };
-      ext.storage.set(entry, callback);
-    }
-    else
-    {
-      var processedData = LZString.compressToUTF16(JSON.stringify(data));
-      ext.storage.remove(key);
-      entry[key] = {
-        lastModified: Date.now(),
-        content: processedData,
-        compressed: true
-      };
-      window.localStorage.setItem(key, JSON.stringify(entry[key]));
-      setTimeout(callback, 0);
-    }
-    callback();
+    localStorage.removeItem(key);
+    localforage.setItem(key, entry, callback);
   }
   exports.IO = {
     resolveFilePath: function(path)
@@ -423,10 +399,6 @@
       {
         if ("content" in entry)
         {
-          if (entry["compressed"])
-          {
-            entry.content = JSON.parse(LZString.decompressFromUTF16(entry.content));
-          }
           for (var _loopIndex15 = 0; _loopIndex15 < entry.content.length; ++_loopIndex15)
           {
             var line = entry.content[_loopIndex15];
@@ -435,7 +407,7 @@
         }
         callback(null);
       }
-      loadFile(file).then(onLoaded, callback);
+      loadFile(file, onLoaded, callback);
     },
     writeToFile: function(file, data, callback)
     {
@@ -447,7 +419,7 @@
       {
         saveFile(toFile, entry.content, callback);
       }
-      loadFile(file).then(onLoaded, callback);
+      loadFile(file, onLoaded, callback);
     },
     renameFile: function(fromFile, newName, callback)
     {
@@ -458,7 +430,7 @@
           ext.storage.set(keyPrefix + newName, entry, callback);
         });
       }
-      loadFile(file).then(onLoaded, callback);
+      loadFile(file, onLoaded, callback);
     },
     removeFile: function(file, callback)
     {
@@ -474,7 +446,7 @@
           lastModified: entry.lastModified
         });
       }
-      loadFile(file).then(onLoaded, callback);
+      loadFile(file, onLoaded, callback);
     }
   };
   return exports;