Issue 7094 - Encapsulate management of subscription filters

lib/filterStorage.js

Index: lib/filterStorage.js
===================================================================
--- a/lib/filterStorage.js
+++ b/lib/filterStorage.js
@@ -163,16 +163,18 @@
   {
     if (this.knownSubscriptions.has(subscription.url))
       return;
 
     this.knownSubscriptions.set(subscription.url, subscription);
     connectSubscriptionFilters(subscription);
 
     filterNotifier.emit("subscription.added", subscription);
+
+    subscription.clearCaches();
   }
 
   /**
    * Removes a subscription from the storage.
    * @param {Subscription} subscription The subscription to be removed.
    */
   removeSubscription(subscription)
   {
@@ -192,21 +194,28 @@
 
   /**
    * Replaces the list of filters in a subscription with a new list.
    * @param {Subscription} subscription The subscription to be updated.
    * @param {Array.<Filter>} filters The new list of filters.
    */
   updateSubscriptionFilters(subscription, filters)
   {
-    disconnectSubscriptionFilters(subscription);
-    let oldFilters = subscription.filters;
-    subscription.filters = filters;
-    connectSubscriptionFilters(subscription);
+    let oldFilters = [...subscription.filters()];
+    disconnectSubscriptionFilters(subscription, oldFilters);
+    subscription.clearFilters();
+
+    for (let filter of filters)
+      subscription.addFilter(filter);
+
+    connectSubscriptionFilters(subscription, filters);
+
     filterNotifier.emit("subscription.updated", subscription, oldFilters);
+
+    subscription.clearCaches();

[Manish Jethani, 2018/11/18 02:25:50]

Typically a subscription will be updated with multiple new filters. In this
case, when the "subscription.updated" event is handled by filterListener.js, it
will end up populating the _filterTextLookup property of the Subscription
instance. After the event has been handled, we clear the lookup here.

   }
 
   /**
    * Adds a user-defined filter to the storage.
    * @param {Filter} filter
    * @param {?SpecialSubscription} [subscription] The subscription that the
    *   filter should be added to.
    * @param {number} [position] The position within the subscription at which
@@ -231,20 +240,20 @@
     {
       // No group for this filter exists, create one
       subscription = SpecialSubscription.createForFilter(filter);
       this.addSubscription(subscription);
       return;
     }
 
     if (typeof position == "undefined")
-      position = subscription.filters.length;
+      position = subscription.filterCount;
 
     filter.addSubscription(subscription);
-    subscription.filters.splice(position, 0, filter);
+    subscription.insertFilterAt(filter, position);
     filterNotifier.emit("filter.added", filter, subscription, position);
   }
 
   /**
    * Removes a user-defined filter from the storage.
    * @param {Filter} filter
    * @param {?SpecialSubscription} [subscription] The subscription that the
    *   filter should be removed from. If not specified, the filter will be
@@ -263,31 +272,32 @@
       if (currentSubscription instanceof SpecialSubscription)
       {
         let positions = [];
         if (typeof position == "undefined")
         {
           let index = -1;
           do
           {
-            index = currentSubscription.filters.indexOf(filter, index + 1);
+            index = currentSubscription.searchFilter(filter, index + 1);
             if (index >= 0)
               positions.push(index);
           } while (index >= 0);
         }
         else
           positions.push(position);
 
         for (let j = positions.length - 1; j >= 0; j--)
         {
           let currentPosition = positions[j];
-          if (currentSubscription.filters[currentPosition] == filter)
+          let currentFilter = currentSubscription.filterAt(currentPosition);
+          if (currentFilter && currentFilter.text == filter.text)
           {
-            currentSubscription.filters.splice(currentPosition, 1);
-            if (currentSubscription.filters.indexOf(filter) < 0)
+            currentSubscription.deleteFilterAt(currentPosition);
+            if (currentSubscription.searchFilter(filter) < 0)
               filter.removeSubscription(currentSubscription);
             filterNotifier.emit("filter.removed", filter, currentSubscription,
                                 currentPosition);
           }
         }
       }
     }
   }
@@ -297,29 +307,30 @@
    * @param {Filter} filter
    * @param {SpecialSubscription} subscription The subscription where the
    *   filter is located.
    * @param {number} oldPosition The current position of the filter.
    * @param {number} newPosition The new position of the filter.
    */
   moveFilter(filter, subscription, oldPosition, newPosition)
   {
-    if (!(subscription instanceof SpecialSubscription) ||
-        subscription.filters[oldPosition] != filter)
-    {
+    if (!(subscription instanceof SpecialSubscription))
       return;
-    }
+
+    let currentFilter = subscription.filterAt(oldPosition);
+    if (!currentFilter || currentFilter.text != filter.text)
+      return;
 
     newPosition = Math.min(Math.max(newPosition, 0),
-                           subscription.filters.length - 1);
+                           subscription.filterCount - 1);
     if (oldPosition == newPosition)
       return;
 
-    subscription.filters.splice(oldPosition, 1);
-    subscription.filters.splice(newPosition, 0, filter);
+    subscription.deleteFilterAt(oldPosition);
+    subscription.insertFilterAt(filter, newPosition);
     filterNotifier.emit("filter.moved", filter, subscription, oldPosition,
                         newPosition);
   }
 
   /**
    * Increases the hit count for a filter by one.
    * @param {Filter} filter
    */
@@ -375,17 +386,23 @@
           knownSubscriptions.set(subscription.url, subscription);
 
         this.fileProperties = parser.fileProperties;
         this.knownSubscriptions = knownSubscriptions;
         Filter.knownFilters = parser.knownFilters;
         Subscription.knownSubscriptions = parser.knownSubscriptions;
 
         if (!silent)
+        {
           filterNotifier.emit("load");
+
+          // Clear any in-memory caches that may have been created during
+          // initialization.
+          clearSubscriptionCaches();

[Manish Jethani, 2018/11/18 02:25:50]

This is not necessary right now but better to do it. It will clear the
"ephemeral" Filter instances from memory, when we finally get to it.

+        }
       }
     };
   }
 
   /**
    * Loads all subscriptions from disk.
    * @returns {Promise} A promise resolved or rejected when loading is complete.
    */
@@ -424,16 +441,17 @@
     }).catch(error =>
     {
       Cu.reportError(error);
       return tryBackup(1);
     }).then(() =>
     {
       this.initialized = true;
       filterNotifier.emit("load");
+      clearSubscriptionCaches();
     });
   }
 
   /**
    * Constructs the file name for a <code>patterns.ini</code> backup.
    * @param {number} backupIndex Number of the backup file (1 being the most
    *   recent).
    * @returns {string} Backup file name.
@@ -471,17 +489,17 @@
   *exportData()
   {
     // Do not persist external subscriptions
     let subscriptions = [];
     for (let subscription of this.subscriptions())
     {
       if (!(subscription instanceof ExternalSubscription) &&
           !(subscription instanceof SpecialSubscription &&
-            subscription.filters.length == 0))
+            subscription.filterCount == 0))
       {
         subscriptions.push(subscription);
       }
     }
 
     yield "# Adblock Plus preferences";
     yield "version=" + this.formatVersion;
 
@@ -492,17 +510,17 @@
     {
       yield* subscription.serialize();
       yield* subscription.serializeFilters();
     }
 
     // Save filter data
     for (let subscription of subscriptions)
     {
-      for (let filter of subscription.filters)
+      for (let filter of subscription.filters())
       {
         if (!saved.has(filter.text))
         {
           yield* filter.serialize();
           saved.add(filter.text);
         }
       }
     }
@@ -642,31 +660,46 @@
 let filterStorage = new FilterStorage();
 
 exports.filterStorage = filterStorage;
 
 /**
  * Connects a subscription to its filters without any notifications.
  * @param {Subscription} subscription The subscription that should be
  *   connected to its filters.
+ * @param {?Array.<Filter>} [filters] A list of filters to which the
+ *   subscription should be connected. If this is not given, the subscription
+ *   is connected to its own filters.
  */
-function connectSubscriptionFilters(subscription)
+function connectSubscriptionFilters(subscription, filters)
 {
   if (!filterStorage.knownSubscriptions.has(subscription.url))
     return;
 
-  for (let filter of subscription.filters)
+  for (let filter of filters || subscription.filters())
     filter.addSubscription(subscription);
 }
 
 /**
  * Disconnects a subscription from its filters without any notifications.
  * @param {Subscription} subscription The subscription that should be
  *   disconnected from its filters.
+ * @param {?Array.<Filter>} [filters] A list of filters from which the
+ *   subscription should be disconnected. If this is not given, the
+ *   subscription is disconnected from its own filters.
  */
-function disconnectSubscriptionFilters(subscription)
+function disconnectSubscriptionFilters(subscription, filters)
 {
   if (!filterStorage.knownSubscriptions.has(subscription.url))
     return;
 
-  for (let filter of subscription.filters)
+  for (let filter of filters || subscription.filters())
     filter.removeSubscription(subscription);
 }
+
+/**
+ * Clears any in-memory caches held by subscriptions in the storage.
+ */
+function clearSubscriptionCaches()
+{
+  for (let subscription of filterStorage.subscriptions())
+    subscription.clearCaches();
+}