Issue 4878 - Start using ESLint for adblockpluscore

lib/synchronizer.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";
+
 /**
  * @fileOverview Manages synchronization of filter subscriptions.
  */
 
-Cu.import("resource://gre/modules/XPCOMUtils.jsm");
-Cu.import("resource://gre/modules/Services.jsm");
+const {XPCOMUtils} = Cu.import("resource://gre/modules/XPCOMUtils.jsm", {});

[kzar, 2017/03/14 10:56:37]

I just noticed no-unused-vars errors for these. Why are these imports here if
we're not using them?

[Wladimir Palant, 2017/03/14 11:08:13]

I guess that they were used before Downloader was split out as a separate class
- and there was no linter to remind us that these imports need to be removed as
well. Feel free to do that now.

[kzar, 2017/03/15 03:13:09]

Done.

+const {Services} = Cu.import("resource://gre/modules/Services.jsm", {});
 
-var {Downloader, Downloadable,
-    MILLIS_IN_SECOND, MILLIS_IN_MINUTE, MILLIS_IN_HOUR, MILLIS_IN_DAY} = require("downloader");
-var {Filter, CommentFilter} = require("filterClasses");
-var {FilterStorage} = require("filterStorage");
-var {FilterNotifier} = require("filterNotifier");
-var {Prefs} = require("prefs");
-var {Subscription, DownloadableSubscription} = require("subscriptionClasses");
-var {Utils} = require("utils");
+const {Downloader, Downloadable,
+       MILLIS_IN_SECOND, MILLIS_IN_MINUTE,
+       MILLIS_IN_HOUR, MILLIS_IN_DAY} = require("downloader");
+const {Filter} = require("filterClasses");
+const {FilterStorage} = require("filterStorage");
+const {FilterNotifier} = require("filterNotifier");
+const {Prefs} = require("prefs");
+const {Subscription, DownloadableSubscription} = require("subscriptionClasses");
+const {Utils} = require("utils");
 
-var INITIAL_DELAY = 1 * MILLIS_IN_MINUTE;
-var CHECK_INTERVAL = 1 * MILLIS_IN_HOUR;
-var DEFAULT_EXPIRATION_INTERVAL = 5 * MILLIS_IN_DAY;
+const INITIAL_DELAY = 1 * MILLIS_IN_MINUTE;
+const CHECK_INTERVAL = 1 * MILLIS_IN_HOUR;
+const DEFAULT_EXPIRATION_INTERVAL = 5 * MILLIS_IN_DAY;
 
 /**
  * The object providing actual downloading functionality.
- * @type Downloader
+ * @type {Downloader}
  */
-var downloader = null;
+let downloader = null;
 
 /**
  * This object is responsible for downloading filter subscriptions whenever
  * necessary.
  * @class
  */
-var Synchronizer = exports.Synchronizer =
+let Synchronizer = exports.Synchronizer =
 {
   /**
    * Called on module startup.
    */
-  init: function()
+  init()
   {
-    downloader = new Downloader(this._getDownloadables.bind(this), INITIAL_DELAY, CHECK_INTERVAL);
-    onShutdown.add(function()
+    downloader = new Downloader(this._getDownloadables.bind(this),
+                                INITIAL_DELAY, CHECK_INTERVAL);
+    onShutdown.add(() =>
     {
       downloader.cancel();
     });
 
     downloader.onExpirationChange = this._onExpirationChange.bind(this);
     downloader.onDownloadStarted = this._onDownloadStarted.bind(this);
     downloader.onDownloadSuccess = this._onDownloadSuccess.bind(this);
     downloader.onDownloadError = this._onDownloadError.bind(this);
   },
 
   /**
    * Checks whether a subscription is currently being downloaded.
-   * @param {String} url  URL of the subscription
-   * @return {Boolean}
+   * @param {string} url  URL of the subscription
+   * @return {boolean}
    */
-  isExecuting: function(url)
+  isExecuting(url)
   {
     return downloader.isDownloading(url);
   },
 
   /**
    * Starts the download of a subscription.
-   * @param {DownloadableSubscription} subscription  Subscription to be downloaded
-   * @param {Boolean} manual  true for a manually started download (should not trigger fallback requests)
+   * @param {DownloadableSubscription} subscription
+   *   Subscription to be downloaded
+   * @param {boolean} manual
+   *   true for a manually started download (should not trigger fallback
+   *   requests)
    */
-  execute: function(subscription, manual)
+  execute(subscription, manual)
   {
     downloader.download(this._getDownloadable(subscription, manual));
   },
 
   /**
    * Yields Downloadable instances for all subscriptions that can be downloaded.
    */
-  _getDownloadables: function*()
+  *_getDownloadables()
   {
     if (!Prefs.subscriptions_autoupdate)
       return;
 
     for (let subscription of FilterStorage.subscriptions)
     {
       if (subscription instanceof DownloadableSubscription)
         yield this._getDownloadable(subscription, false);
     }
   },
 
   /**
    * Creates a Downloadable instance for a subscription.
+   * @param {Subscription} subscription
+   * @param {boolean} manual
+   * @return {Downloadable}
    */
-  _getDownloadable: function(/**Subscription*/ subscription, /**Boolean*/ manual) /**Downloadable*/
+  _getDownloadable(subscription, manual)
   {
     let result = new Downloadable(subscription.url);
     if (subscription.lastDownload != subscription.lastSuccess)
       result.lastError = subscription.lastDownload * MILLIS_IN_SECOND;
     result.lastCheck = subscription.lastCheck * MILLIS_IN_SECOND;
     result.lastVersion = subscription.version;
     result.softExpiration = subscription.softExpiration * MILLIS_IN_SECOND;
     result.hardExpiration = subscription.expires * MILLIS_IN_SECOND;
     result.manual = manual;
     result.downloadCount = subscription.downloadCount;
     return result;
   },
 
-  _onExpirationChange: function(downloadable)
+  _onExpirationChange(downloadable)
   {
     let subscription = Subscription.fromURL(downloadable.url);
-    subscription.lastCheck = Math.round(downloadable.lastCheck / MILLIS_IN_SECOND);
-    subscription.softExpiration = Math.round(downloadable.softExpiration / MILLIS_IN_SECOND);
-    subscription.expires = Math.round(downloadable.hardExpiration / MILLIS_IN_SECOND);
+    subscription.lastCheck = Math.round(
+      downloadable.lastCheck / MILLIS_IN_SECOND
+    );
+    subscription.softExpiration = Math.round(
+      downloadable.softExpiration / MILLIS_IN_SECOND
+    );
+    subscription.expires = Math.round(
+      downloadable.hardExpiration / MILLIS_IN_SECOND
+    );
   },
 
-  _onDownloadStarted: function(downloadable)
+  _onDownloadStarted(downloadable)
   {
     let subscription = Subscription.fromURL(downloadable.url);
     FilterNotifier.triggerListeners("subscription.downloading", subscription);
   },
 
-  _onDownloadSuccess: function(downloadable, responseText, errorCallback, redirectCallback)
+  _onDownloadSuccess(downloadable, responseText, errorCallback,
+                     redirectCallback)
   {
     let lines = responseText.split(/[\r\n]+/);
-    let match = /\[Adblock(?:\s*Plus\s*([\d\.]+)?)?\]/i.exec(lines[0]);
-    if (!match)
+    let headerMatch = /\[Adblock(?:\s*Plus\s*([\d.]+)?)?\]/i.exec(lines[0]);
+    if (!headerMatch)
       return errorCallback("synchronize_invalid_data");
-    let minVersion = match[1];
+    let minVersion = headerMatch[1];
 
     // Don't remove parameter comments immediately but add them to a list first,
     // they need to be considered in the checksum calculation.
     let remove = [];
     let params = {
       redirect: null,
       homepage: null,
       title: null,
       version: null,
       expires: null
@@ skipping 17 matching lines @@
           if (checksum && checksum != value.replace(/=+$/, ""))
             return errorCallback("synchronize_checksum_mismatch");
         }
       }
     }
 
     if (params.redirect)
       return redirectCallback(params.redirect);
 
     // Handle redirects
-    let subscription = Subscription.fromURL(downloadable.redirectURL || downloadable.url);
-    if (downloadable.redirectURL && downloadable.redirectURL != downloadable.url)
+    let subscription = Subscription.fromURL(downloadable.redirectURL ||
+                                            downloadable.url);
+    if (downloadable.redirectURL &&
+        downloadable.redirectURL != downloadable.url)
     {
       let oldSubscription = Subscription.fromURL(downloadable.url);
       subscription.title = oldSubscription.title;
       subscription.disabled = oldSubscription.disabled;
       subscription.lastCheck = oldSubscription.lastCheck;
 
       let listed = (oldSubscription.url in FilterStorage.knownSubscriptions);
       if (listed)
         FilterStorage.removeSubscription(oldSubscription);
 
       delete Subscription.knownSubscriptions[oldSubscription.url];
 
       if (listed)
         FilterStorage.addSubscription(subscription);
     }
 
     // The download actually succeeded
-    subscription.lastSuccess = subscription.lastDownload = Math.round(Date.now() / MILLIS_IN_SECOND);
+    subscription.lastSuccess = subscription.lastDownload = Math.round(
+      Date.now() / MILLIS_IN_SECOND
+    );
     subscription.downloadStatus = "synchronize_ok";
     subscription.downloadCount = downloadable.downloadCount;
     subscription.errors = 0;
 
     // Remove lines containing parameters
     for (let i = remove.length - 1; i >= 0; i--)
       lines.splice(remove[i], 1);
 
     // Process parameters
     if (params.homepage)
@@ skipping 29 matching lines @@
       if (match)
       {
         let interval = parseInt(match[1], 10);
         if (match[2])
           expirationInterval = interval * MILLIS_IN_HOUR;
         else
           expirationInterval = interval * MILLIS_IN_DAY;
       }
     }
 
-    let [softExpiration, hardExpiration] = downloader.processExpirationInterval(expirationInterval);
+    let [
+      softExpiration,
+      hardExpiration
+    ] = downloader.processExpirationInterval(expirationInterval);
     subscription.softExpiration = Math.round(softExpiration / MILLIS_IN_SECOND);
     subscription.expires = Math.round(hardExpiration / MILLIS_IN_SECOND);
 
     if (minVersion)
       subscription.requiredVersion = minVersion;
     else
       delete subscription.requiredVersion;
 
     // Process filters
     lines.shift();
     let filters = [];
     for (let line of lines)
     {
       line = Filter.normalize(line);
       if (line)
         filters.push(Filter.fromText(line));
     }
 
     FilterStorage.updateSubscriptionFilters(subscription, filters);
 
     return undefined;
   },
 
-  _onDownloadError: function(downloadable, downloadURL, error, channelStatus, responseStatus, redirectCallback)
+  _onDownloadError(downloadable, downloadURL, error, channelStatus,
+                   responseStatus, redirectCallback)
   {
     let subscription = Subscription.fromURL(downloadable.url);
     subscription.lastDownload = Math.round(Date.now() / MILLIS_IN_SECOND);
     subscription.downloadStatus = error;
 
     // Request fallback URL if necessary - for automatic updates only
     if (!downloadable.manual)
     {
       subscription.errors++;
 
-      if (redirectCallback && subscription.errors >= Prefs.subscriptions_fallbackerrors && /^https?:\/\//i.test(subscription.url))
+      if (redirectCallback &&
+          subscription.errors >= Prefs.subscriptions_fallbackerrors &&
+          /^https?:\/\//i.test(subscription.url))
       {
         subscription.errors = 0;
 
         let fallbackURL = Prefs.subscriptions_fallbackurl;
-        let {addonVersion} = require("info");
-        fallbackURL = fallbackURL.replace(/%VERSION%/g, encodeURIComponent(addonVersion));
-        fallbackURL = fallbackURL.replace(/%SUBSCRIPTION%/g, encodeURIComponent(subscription.url));
-        fallbackURL = fallbackURL.replace(/%URL%/g, encodeURIComponent(downloadURL));
-        fallbackURL = fallbackURL.replace(/%ERROR%/g, encodeURIComponent(error));
-        fallbackURL = fallbackURL.replace(/%CHANNELSTATUS%/g, encodeURIComponent(channelStatus));
-        fallbackURL = fallbackURL.replace(/%RESPONSESTATUS%/g, encodeURIComponent(responseStatus));
+        const {addonVersion} = require("info");
+        fallbackURL = fallbackURL.replace(/%VERSION%/g,
+                                          encodeURIComponent(addonVersion));
+        fallbackURL = fallbackURL.replace(/%SUBSCRIPTION%/g,
+                                          encodeURIComponent(subscription.url));
+        fallbackURL = fallbackURL.replace(/%URL%/g,
+                                          encodeURIComponent(downloadURL));
+        fallbackURL = fallbackURL.replace(/%ERROR%/g,
+                                          encodeURIComponent(error));
+        fallbackURL = fallbackURL.replace(/%CHANNELSTATUS%/g,
+                                          encodeURIComponent(channelStatus));
+        fallbackURL = fallbackURL.replace(/%RESPONSESTATUS%/g,
+                                          encodeURIComponent(responseStatus));
 
         let request = new XMLHttpRequest();
         request.mozBackgroundRequest = true;
         request.open("GET", fallbackURL);
         request.overrideMimeType("text/plain");
         request.channel.loadFlags = request.channel.loadFlags |
                                     request.channel.INHIBIT_CACHING |
                                     request.channel.VALIDATE_ALWAYS;
-        request.addEventListener("load", function(ev)
+        request.addEventListener("load", ev =>
         {
           if (onShutdown.done)
             return;
 
           if (!(subscription.url in FilterStorage.knownSubscriptions))
             return;
 
           let match = /^(\d+)(?:\s+(\S+))?$/.exec(request.responseText);
-          if (match && match[1] == "301" && match[2] && /^https?:\/\//i.test(match[2])) // Moved permanently
+          if (match && match[1] == "301" &&    // Moved permanently
+              match[2] && /^https?:\/\//i.test(match[2]))
+          {
             redirectCallback(match[2]);
-          else if (match && match[1] == "410")        // Gone
+          }
+          else if (match && match[1] == "410") // Gone
           {
-            let data = "[Adblock]\n" + subscription.filters.map((f) => f.text).join("\n");
+            let data = "[Adblock]\n" +
+              subscription.filters.map(f => f.text).join("\n");
             redirectCallback("data:text/plain," + encodeURIComponent(data));
           }
         }, false);
         request.send(null);
       }
     }
-  },
+  }
 };
 Synchronizer.init();