Issue 6857 - Do not serialize empty special subscriptions

lib/filterStorage.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * 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";
 
 /**
  * @fileOverview FilterStorage class responsible for managing user's
  *               subscriptions and filters.
  */
 
 const {IO} = require("io");
 const {Prefs} = require("prefs");
 const {Filter, ActiveFilter} = require("./filterClasses");
 const {Subscription, SpecialSubscription,
        ExternalSubscription} = require("./subscriptionClasses");
-const {FilterNotifier} = require("./filterNotifier");
+const {filterNotifier} = require("./filterNotifier");
+const {INIParser} = require("./iniParser");
 
 /**
  * Version number of the filter storage file format.
  * @type {number}
  */
 let formatVersion = 5;
 
 /**
  * This class reads user's filters from disk, manages them in memory
  * and writes them back.
@@ skipping 31 matching lines @@
    */
   firstRun: false,
 
   /**
    * Map of properties listed in the filter storage file before the sections
    * start. Right now this should be only the format version.
    */
   fileProperties: Object.create(null),
 
   /**
-   * List of filter subscriptions containing all filters
-   * @type {Subscription[]}
-   */
-  subscriptions: [],
+   * Yields subscriptions containing all filters
+   * @yields {Subscription}
+   */
+  *subscriptions()
+  {
+    yield* this.knownSubscriptions.values();
+  },
+
+  /**
+   * Number of known subscriptions.
+   * @type {number}
+   */
+  get subscriptionCount()
+  {
+    return this.knownSubscriptions.size;
+  },
 
   /**
    * Map of subscriptions already on the list, by their URL/identifier
    * @type {Map.<string,Subscription>}
    */
   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)
   {
     let generalSubscription = null;
-    for (let subscription of FilterStorage.subscriptions)
+    for (let subscription of FilterStorage.knownSubscriptions.values())
     {
       if (subscription instanceof SpecialSubscription && !subscription.disabled)
       {
         // Always prefer specialized subscriptions
         if (subscription.isDefaultFor(filter))
           return subscription;
 
         // If this is a general subscription - store it as fallback
         if (!generalSubscription &&
             (!subscription.defaults || !subscription.defaults.length))
         {
           generalSubscription = subscription;
         }
       }
     }
     return generalSubscription;
   },
 
   /**
    * Adds a filter subscription to the list
    * @param {Subscription} subscription filter subscription to be added
    */
   addSubscription(subscription)
   {
     if (FilterStorage.knownSubscriptions.has(subscription.url))
       return;
 
-    FilterStorage.subscriptions.push(subscription);
     FilterStorage.knownSubscriptions.set(subscription.url, subscription);
     addSubscriptionFilters(subscription);
 
-    FilterNotifier.triggerListeners("subscription.added", subscription);
+    filterNotifier.emit("subscription.added", subscription);
   },
 
   /**
    * Removes a filter subscription from the list
    * @param {Subscription} subscription filter subscription to be removed
    */
   removeSubscription(subscription)
   {
-    for (let i = 0; i < FilterStorage.subscriptions.length; i++)
-    {
-      if (FilterStorage.subscriptions[i].url == subscription.url)
-      {
-        removeSubscriptionFilters(subscription);
-
-        FilterStorage.subscriptions.splice(i--, 1);
-        FilterStorage.knownSubscriptions.delete(subscription.url);
-        FilterNotifier.triggerListeners("subscription.removed", subscription);
-        return;
-      }
-    }
-  },
-
-  /**
-   * Moves a subscription in the list to a new position.
-   * @param {Subscription} subscription filter subscription to be moved
-   * @param {Subscription} [insertBefore] filter subscription to insert before
-   *        (if omitted the subscription will be put at the end of the list)
-   */
-  moveSubscription(subscription, insertBefore)
-  {
-    let currentPos = FilterStorage.subscriptions.indexOf(subscription);
-    if (currentPos < 0)
+    if (!FilterStorage.knownSubscriptions.has(subscription.url))
       return;
 
-    let newPos = -1;
-    if (insertBefore)
-      newPos = FilterStorage.subscriptions.indexOf(insertBefore);
-
-    if (newPos < 0)
-      newPos = FilterStorage.subscriptions.length;
-
-    if (currentPos < newPos)
-      newPos--;
-    if (currentPos == newPos)
-      return;
-
-    FilterStorage.subscriptions.splice(currentPos, 1);
-    FilterStorage.subscriptions.splice(newPos, 0, subscription);
-    FilterNotifier.triggerListeners("subscription.moved", subscription);
+    removeSubscriptionFilters(subscription);
+
+    FilterStorage.knownSubscriptions.delete(subscription.url);
+
+    // This should be the last remaining reference to the Subscription
+    // object.
+    Subscription.knownSubscriptions.delete(subscription.url);
+
+    filterNotifier.emit("subscription.removed", subscription);
   },
 
   /**
    * Replaces the list of filters in a subscription by a new list
    * @param {Subscription} subscription filter subscription to be updated
    * @param {Filter[]} filters new filter list
    */
   updateSubscriptionFilters(subscription, filters)
   {
     removeSubscriptionFilters(subscription);
-    subscription.oldFilters = subscription.filters;
+    let oldFilters = subscription.filters;
     subscription.filters = filters;
     addSubscriptionFilters(subscription);
-    FilterNotifier.triggerListeners("subscription.updated", subscription);
-    delete subscription.oldFilters;
+    filterNotifier.emit("subscription.updated", subscription, oldFilters);
   },
 
   /**
    * Adds a user-defined filter to the list
    * @param {Filter} filter
    * @param {SpecialSubscription} [subscription]
    *   particular group that the filter should be added to
    * @param {number} [position]
    *   position within the subscription at which the filter should be added
    */
   addFilter(filter, subscription, position)
   {
     if (!subscription)
     {
-      if (filter.subscriptions.some(s => s instanceof SpecialSubscription &&
-                                         !s.disabled))
-      {
-        return;   // No need to add
+      for (let currentSubscription of filter.subscriptions())
+      {
+        if (currentSubscription instanceof SpecialSubscription &&
+            !currentSubscription.disabled)
+        {
+          return;   // No need to add
+        }
       }
       subscription = FilterStorage.getGroupForFilter(filter);
     }
     if (!subscription)
     {
       // No group for this filter exists, create one
       subscription = SpecialSubscription.createForFilter(filter);
       this.addSubscription(subscription);
       return;
     }
 
     if (typeof position == "undefined")
       position = subscription.filters.length;
 
-    if (filter.subscriptions.indexOf(subscription) < 0)
-      filter.subscriptions.push(subscription);
+    filter.addSubscription(subscription);
     subscription.filters.splice(position, 0, filter);
-    FilterNotifier.triggerListeners("filter.added", filter, subscription,
-                                    position);
+    filterNotifier.emit("filter.added", filter, subscription, position);
   },
 
   /**
    * Removes a user-defined filter from the list
    * @param {Filter} filter
    * @param {SpecialSubscription} [subscription] a particular filter group that
    *      the filter should be removed from (if ommited will be removed from all
    *      subscriptions)
    * @param {number} [position]  position inside the filter group at which the
    *      filter should be removed (if ommited all instances will be removed)
    */
   removeFilter(filter, subscription, position)
   {
     let subscriptions = (
-      subscription ? [subscription] : filter.subscriptions.slice()
+      subscription ? [subscription] : filter.subscriptions()
     );
-    for (let i = 0; i < subscriptions.length; i++)
-    {
-      let currentSubscription = subscriptions[i];
+    for (let currentSubscription of subscriptions)
+    {
       if (currentSubscription instanceof SpecialSubscription)
       {
         let positions = [];
         if (typeof position == "undefined")
         {
           let index = -1;
           do
           {
             index = currentSubscription.filters.indexOf(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)
           {
             currentSubscription.filters.splice(currentPosition, 1);
             if (currentSubscription.filters.indexOf(filter) < 0)
-            {
-              let index = filter.subscriptions.indexOf(currentSubscription);
-              if (index >= 0)
-                filter.subscriptions.splice(index, 1);
-            }
-            FilterNotifier.triggerListeners(
-              "filter.removed", filter, currentSubscription, currentPosition
-            );
+              filter.removeSubscription(currentSubscription);
+            filterNotifier.emit("filter.removed", filter, currentSubscription,
+                                currentPosition);
           }
         }
       }
     }
   },
 
   /**
    * Moves a user-defined filter to a new position
    * @param {Filter} filter
    * @param {SpecialSubscription} subscription filter group where the filter is
    *                                           located
    * @param {number} oldPosition current position of the filter
    * @param {number} newPosition new position of the filter
    */
   moveFilter(filter, subscription, oldPosition, newPosition)
   {
     if (!(subscription instanceof SpecialSubscription) ||
         subscription.filters[oldPosition] != filter)
     {
       return;
     }
 
     newPosition = Math.min(Math.max(newPosition, 0),
                            subscription.filters.length - 1);
     if (oldPosition == newPosition)
       return;
 
     subscription.filters.splice(oldPosition, 1);
     subscription.filters.splice(newPosition, 0, filter);
-    FilterNotifier.triggerListeners("filter.moved", filter, subscription,
-                                    oldPosition, newPosition);
+    filterNotifier.emit("filter.moved", filter, subscription, oldPosition,
+                        newPosition);
   },
 
   /**
    * Increases the hit count for a filter by one
    * @param {Filter} filter
    */
   increaseHitCount(filter)
   {
     if (!Prefs.savestats || !(filter instanceof ActiveFilter))
       return;
@@ skipping 39 matching lines @@
     return line =>
     {
       parser.process(line);
       if (line === null)
       {
         let knownSubscriptions = new Map();
         for (let subscription of parser.subscriptions)
           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)
-          FilterNotifier.triggerListeners("load");
+          filterNotifier.emit("load");
       }
     };
   },
 
   /**
    * Loads all subscriptions from the disk.
    * @return {Promise} promise resolved or rejected when loading is complete
    */
   loadFromDisk()
   {
     let tryBackup = backupIndex =>
     {
       return this.restoreBackup(backupIndex, true).then(() =>
       {
-        if (this.subscriptions.length == 0)
+        if (this.knownSubscriptions.size == 0)
           return tryBackup(backupIndex + 1);
       }).catch(error =>
       {
         // Give up
       });
     };
 
     return IO.statFile(this.sourceFile).then(statData =>
     {
       if (!statData.exists)
       {
         this.firstRun = true;
         return;
       }
 
       let parser = this.importData(true);
       return IO.readFromFile(this.sourceFile, parser).then(() =>
       {
         parser(null);
-        if (this.subscriptions.length == 0)
+        if (this.knownSubscriptions.size == 0)
         {
           // No filter subscriptions in the file, this isn't right.
           throw new Error("No data in the file");
         }
       });
     }).catch(error =>
     {
       Cu.reportError(error);
       return tryBackup(1);
     }).then(() =>
     {
       this.initialized = true;
-      FilterNotifier.triggerListeners("load");
+      filterNotifier.emit("load");
     });
   },
 
   /**
    * Constructs the file name for a patterns.ini backup.
    * @param {number} backupIndex
    *    number of the backup file (1 being the most recent)
    * @return {string} backup file name
    */
   getBackupName(backupIndex)
@@ skipping 20 matching lines @@
       return this.saveToDisk();
     });
   },
 
   /**
    * Generator serializing filter data and yielding it line by line.
    */
   *exportData()
   {
     // Do not persist external subscriptions
-    let subscriptions = this.subscriptions.filter(
-      s => !(s instanceof ExternalSubscription) &&
-           !(s instanceof SpecialSubscription && s.filters.length == 0)
-    );
+    let subscriptions = [];
+    for (let subscription of this.subscriptions())
+    {
+      if (!(subscription instanceof ExternalSubscription) &&
+          !(subscription instanceof SpecialSubscription &&
+            subscription.filters.length == 0))
+      {
+        subscriptions.push(subscription);
+      }
+    }
 
     yield "# Adblock Plus preferences";
     yield "version=" + formatVersion;
 
     let saved = new Set();
     let buf = [];
 
     // Save subscriptions
     for (let subscription of subscriptions)
     {
@@ skipping 104 matching lines @@
       return renameBackup(Prefs.patternsbackups - 1);
     }).catch(error =>
     {
       // Errors during backup creation shouldn't prevent writing filters.
       Cu.reportError(error);
     }).then(() =>
     {
       return IO.writeToFile(this.sourceFile, this.exportData());
     }).then(() =>
     {
-      FilterNotifier.triggerListeners("save");
+      filterNotifier.emit("save");
     }).catch(error =>
     {
       // If saving failed, report error but continue - we still have to process
       // flags.
       Cu.reportError(error);
     }).then(() =>
     {
       this._saving = false;
       if (this._needsSave)
       {
@@ skipping 46 matching lines @@
  * 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 (!FilterStorage.knownSubscriptions.has(subscription.url))
     return;
 
   for (let filter of subscription.filters)
-    filter.subscriptions.push(subscription);
+    filter.addSubscription(subscription);
 }
 
 /**
  * Removes subscription's filters from the subscription without any
  * notifications.
  * @param {Subscription} subscription filter subscription to be removed
  */
 function removeSubscriptionFilters(subscription)
 {
   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);
-  }
+    filter.removeSubscription(subscription);
 }
-
-/**
- * Listener returned by FilterStorage.importData(), parses filter data.
- * @constructor
- */
-function INIParser()
-{
-  this.fileProperties = this.curObj = {};
-  this.subscriptions = [];
-  this.knownFilters = new Map();
-  this.knownSubscriptions = new Map();
-}
-INIParser.prototype =
-{
-  linesProcessed: 0,
-  subscriptions: null,
-  knownFilters: null,
-  knownSubscriptions: null,
-  wantObj: true,
-  fileProperties: null,
-  curObj: null,
-  curSection: null,
-
-  process(val)
-  {
-    let origKnownFilters = Filter.knownFilters;
-    Filter.knownFilters = this.knownFilters;
-    let origKnownSubscriptions = Subscription.knownSubscriptions;
-    Subscription.knownSubscriptions = this.knownSubscriptions;
-    let match;
-    try
-    {
-      if (this.wantObj === true && (match = /^(\w+)=(.*)$/.exec(val)))
-        this.curObj[match[1]] = match[2];
-      else if (val === null || (match = /^\s*\[(.+)\]\s*$/.exec(val)))
-      {
-        if (this.curObj)
-        {
-          // Process current object before going to next section
-          switch (this.curSection)
-          {
-            case "filter":
-              if ("text" in this.curObj)
-                Filter.fromObject(this.curObj);
-              break;
-            case "subscription": {
-              let subscription = Subscription.fromObject(this.curObj);
-              if (subscription)
-                this.subscriptions.push(subscription);
-              break;
-            }
-            case "subscription filters":
-              if (this.subscriptions.length)
-              {
-                let subscription = this.subscriptions[
-                  this.subscriptions.length - 1
-                ];
-                for (let text of this.curObj)
-                {
-                  let filter = Filter.fromText(text);
-                  subscription.filters.push(filter);
-                  filter.subscriptions.push(subscription);
-                }
-              }
-              break;
-          }
-        }
-
-        if (val === null)
-          return;
-
-        this.curSection = match[1].toLowerCase();
-        switch (this.curSection)
-        {
-          case "filter":
-          case "subscription":
-            this.wantObj = true;
-            this.curObj = {};
-            break;
-          case "subscription filters":
-            this.wantObj = false;
-            this.curObj = [];
-            break;
-          default:
-            this.wantObj = null;
-            this.curObj = null;
-        }
-      }
-      else if (this.wantObj === false && val)
-        this.curObj.push(val.replace(/\\\[/g, "["));
-    }
-    finally
-    {
-      Filter.knownFilters = origKnownFilters;
-      Subscription.knownSubscriptions = origKnownSubscriptions;
-    }
-  }
-};