Issue 6559 - Use Map object for known subscriptions

lib/filterStorage.js

Index: lib/filterStorage.js
===================================================================
--- a/lib/filterStorage.js
+++ b/lib/filterStorage.js
@@ -81,19 +81,19 @@
   /**
    * List of filter subscriptions containing all filters
    * @type {Subscription[]}
    */
   subscriptions: [],
 
   /**
    * Map of subscriptions already on the list, by their URL/identifier
-   * @type {Object}
+   * @type {Map.<string,Subscription>}
    */
-  knownSubscriptions: Object.create(null),
+  knownSubscriptions: new Map(),
 
   /**
    * Finds the filter group that a filter should be added to by default. Will
    * return null if this group doesn't exist yet.
    * @param {Filter} filter
    * @return {?SpecialSubscription}
    */
   getGroupForFilter(filter)
@@ -119,21 +119,21 @@
   },
 
   /**
    * Adds a filter subscription to the list
    * @param {Subscription} subscription filter subscription to be added
    */
   addSubscription(subscription)
   {
-    if (subscription.url in FilterStorage.knownSubscriptions)
+    if (FilterStorage.knownSubscriptions.has(subscription.url))
       return;
 
     FilterStorage.subscriptions.push(subscription);
-    FilterStorage.knownSubscriptions[subscription.url] = subscription;
+    FilterStorage.knownSubscriptions.set(subscription.url, subscription);
     addSubscriptionFilters(subscription);
 
     FilterNotifier.triggerListeners("subscription.added", subscription);
   },
 
   /**
    * Removes a filter subscription from the list
    * @param {Subscription} subscription filter subscription to be removed
@@ -142,17 +142,17 @@
   {
     for (let i = 0; i < FilterStorage.subscriptions.length; i++)
     {
       if (FilterStorage.subscriptions[i].url == subscription.url)
       {
         removeSubscriptionFilters(subscription);
 
         FilterStorage.subscriptions.splice(i--, 1);
-        delete FilterStorage.knownSubscriptions[subscription.url];
+        FilterStorage.knownSubscriptions.delete(subscription.url);
         FilterNotifier.triggerListeners("subscription.removed", subscription);
         return;
       }
     }
   },
 
   /**
    * Moves a subscription in the list to a new position.
@@ -363,19 +363,19 @@
   importData(silent)
   {
     let parser = new INIParser();
     return line =>
     {
       parser.process(line);
       if (line === null)
       {
-        let knownSubscriptions = Object.create(null);
+        let knownSubscriptions = new Map();
         for (let subscription of parser.subscriptions)
-          knownSubscriptions[subscription.url] = subscription;
+          knownSubscriptions.set(subscription.url, subscription);
 
         this.fileProperties = parser.fileProperties;
         this.subscriptions = parser.subscriptions;
         this.knownSubscriptions = knownSubscriptions;
         Filter.knownFilters = parser.knownFilters;
         Subscription.knownSubscriptions = parser.knownSubscriptions;
 
         if (!silent)
@@ -653,31 +653,31 @@
 
 /**
  * Joins subscription's filters to the subscription without any notifications.
  * @param {Subscription} subscription
  *   filter subscription that should be connected to its filters
  */
 function addSubscriptionFilters(subscription)
 {
-  if (!(subscription.url in FilterStorage.knownSubscriptions))
+  if (!FilterStorage.knownSubscriptions.has(subscription.url))
     return;
 
   for (let filter of subscription.filters)
     filter.subscriptions.push(subscription);
 }
 
 /**
  * Removes subscription's filters from the subscription without any
  * notifications.
  * @param {Subscription} subscription filter subscription to be removed
  */
 function removeSubscriptionFilters(subscription)
 {
-  if (!(subscription.url in FilterStorage.knownSubscriptions))
+  if (!FilterStorage.knownSubscriptions.has(subscription.url))
     return;
 
   for (let filter of subscription.filters)
   {
     let i = filter.subscriptions.indexOf(subscription);
     if (i >= 0)
       filter.subscriptions.splice(i, 1);
   }
@@ -687,17 +687,17 @@
  * Listener returned by FilterStorage.importData(), parses filter data.
  * @constructor
  */
 function INIParser()
 {
   this.fileProperties = this.curObj = {};
   this.subscriptions = [];
   this.knownFilters = new Map();
-  this.knownSubscriptions = Object.create(null);
+  this.knownSubscriptions = new Map();
 }
 INIParser.prototype =
 {
   linesProcessed: 0,
   subscriptions: null,
   knownFilters: null,
   knownSubscriptions: null,
   wantObj: true,