Issue 4023 - The logic for splitting up storage.local into 1MB chunks does not work

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/>.
  */
 
 "use strict";
 
 const keyPrefix = "file:";
 
 function fileToKey(file, chunk)
 {
   let key = keyPrefix;
 
+  if (typeof file == "string")
+    return file;
+
   if (file instanceof FakeFile)
     key += file.path;
   else
     key += file.spec;
 
-  if (typeof chunk != "undefined")
-    key += ":" + chunk;
-
   return key;
 }
 
 function loadFile(file)
 {
   return new Promise((resolve, reject) =>
   {
     let key = fileToKey(file);
     ext.storage.get([key], items =>
     {
       let entry = items[key];
+      if (entry && entry.isSplit)
+      {
+        // Load both left and right parts and combine them
+        return Promise.all([loadFile(key + "_l"), loadFile(key + "_r")]).
+                           then(values => 
+                           { 
+                             entry.content = values[0].content.concat(values[1].content); 
+                             resolve(entry);
+                           }).catch(() =>
+                           {
+                             reject(new Error("File doesn't exist"));
+                           });           
+      }
       if (entry)
         resolve(entry);
       else
         reject(new Error("File doesn't exist"));
     });
   });
 }
 
 exports.IO =
 {
   resolveFilePath: function(path)
   {
     return new FakeFile(path);
   },
 
   readFromFile: function(file, listener, callback)
   {
     function onLoaded(entry)
     {
       if ("content" in entry)
       {
         for (let line of entry.content)
           listener.process(line);
-
-        listener.process(null);
-        callback(null);
       }
-      else
-      {
-        let keys = [];
-        for (let i = 0; i < entry.chunks; i++)
-          keys.push(fileToKey(file, i));
-
-        ext.storage.get(keys, items =>
-        {
-           for (let key of keys)
-             for (let line of items[key])
-               listener.process(line);
-
-           listener.process(null);
-           callback(null);
-        });
-      }
+      callback(null);
     }
 
     loadFile(file).then(onLoaded, callback);
   },
 
   writeToFile: function(file, data, callback)
   {
-    let items = {};
-    let entry = items[fileToKey(file)] = {lastModified: Date.now()};
-
-    if (typeof browser == "object")
+    let entry = {};
+    var key = fileToKey(file);
+    entry[key] = {lastModified: Date.now(), content: data};
+    try
     {
-      loadFile(file).catch(() => null)
-                    .then(oldEntry =>
-      {
-        let quota = 1024 * 1024 / 2 - 1000;
-        let chunks = [];
-        let chunk = [];
-        let chunkSize = 0;
-
-        for (let line of data)
-        {
-          if (line.length + chunkSize > quota)
-          {
-            chunks.push(chunk);
-            chunk = [];
-            chunkSize = 0;
-          }
-
-          chunk.push(line);
-          chunkSize += line.length;
-        }
-        chunks.push(chunk);
-
-        for (let i = 0; i < chunks.length; i++)
-          items[fileToKey(file, i)] = chunks[i];
-        entry.chunks = chunks.length;
-        ext.storage.set(items, callback);
-
-        if (oldEntry && "chunks" in oldEntry)
-          for (let i = entry.chunks; i < oldEntry.chunks; i++)
-            ext.storage.remove(fileToKey(file, i));
-      });
+      ext.storage.set(entry, callback);
     }
-    else
+    catch(e)
     {
-      entry.content = data;
-      ext.storage.set(items, callback);
+      // Edge throws an exception when trying to write files larger than 1Mb.
+      // Split the file in halfs and write them.
+      var leftPart = data.slice(0, data.length / 2);
+      var rightPart = data.slice(data.length / 2, data.length);
+      exports.IO.writeToFile(key + "_l", leftPart);
+      exports.IO.writeToFile(key + "_r", rightPart);
+      entry[key].content = null;
+      entry[key].isSplit = true;
+      ext.storage.set(entry, callback);
     }
   },
 
   statFile: function(file, callback)
   {
     function onLoaded(entry)
     {
       callback(null, {
         exists: true,
         lastModified: entry.lastModified
       });
     }
 
     loadFile(file).then(onLoaded, callback);
   }
 };