Issue 5137 - [emscripten] Added basic filter storage implementation

lib/filterStorage.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
- * Copyright (C) 2006-2017 eyeo GmbH
+ * 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
  * 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 {FilterStorage} = require("compiled");
-const {ArrayLike} = require("coreUtils");

[Wladimir Palant, 2017/05/01 14:47:25]

This is left-over from a previous iteration, I already removed this locally.

 const {Subscription, SpecialSubscription} = require("subscriptionClasses");
-const {ActiveFilter} = require("filterClasses");
-const {Prefs} = require("prefs");
 
 // Backwards compatibility
 FilterStorage.getGroupForFilter = FilterStorage.getSubscriptionForFilter;
 
 /**
  * This property allows iterating over the list of subscriptions. It will delete
  * references automatically at the end of the current loop iteration. If you
  * need persistent references or element access by position you should use
  * FilterStorage.subscriptionAt() instead.
  * @type {Iterable}
  */
 FilterStorage.subscriptions = {
-  [Symbol.iterator]: function*()
+  *[Symbol.iterator]()
   {
     for (let i = 0, l = FilterStorage.subscriptionCount; i < l; i++)
     {
       let subscription = FilterStorage.subscriptionAt(i);
       try
       {
         yield subscription;
       }
       finally
       {
         subscription.delete();
       }
     }
   }
 };
 
 /**
  * Adds a user-defined filter to the most suitable subscription in the list,
  * creates one if none found.
  * @param {Filter} filter
+ * @returns {boolean}
+ *    false if the filter was already in the list and no adding was performed
  */
 FilterStorage.addFilter = function(filter)
 {
   for (let subscription of this.subscriptions)
     if (!subscription.disabled && subscription.indexOfFilter(filter) >= 0)
-      return;
+      return false;
 
   let subscription = this.getSubscriptionForFilter(filter);
-  if (!subscription)
+  try
   {
-    subscription = Subscription.fromURL(null);
-    subscription.makeDefaultFor(filter);
-    this.addSubscription(subscription);
+    if (!subscription)
+    {
+      subscription = Subscription.fromURL(null);
+      subscription.makeDefaultFor(filter);
+      this.addSubscription(subscription);
+    }
+    subscription.insertFilterAt(filter, subscription.filterCount);
   }
-  subscription.insertFilterAt(filter, subscription.filterCount);
-  subscription.delete();
+  finally
+  {
+    if (subscription)
+      subscription.delete();
+  }
   return true;
 };
 
 /**
  * Removes a user-defined filter from the list
  * @param {Filter} filter
  */
 FilterStorage.removeFilter = function(filter)
 {
   for (let subscription of this.subscriptions)
   {
     if (subscription instanceof SpecialSubscription)
     {
       while (true)
       {
         let index = subscription.indexOfFilter(filter);
         if (index >= 0)
           subscription.removeFilterAt(index);
         else
           break;
       }
     }
   }
 };
 
 exports.FilterStorage = FilterStorage;