Issue 4878 - Start using ESLint for adblockpluscore

lib/downloader.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";
 
-/* globals XMLHttpRequest */
-
 /**
  * @fileOverview Downloads a set of URLs in regular time intervals.
  */
 
-let {Utils} = require("utils");
-
-let MILLIS_IN_SECOND = exports.MILLIS_IN_SECOND = 1000;
-let MILLIS_IN_MINUTE = exports.MILLIS_IN_MINUTE = 60 * MILLIS_IN_SECOND;
-let MILLIS_IN_HOUR = exports.MILLIS_IN_HOUR = 60 * MILLIS_IN_MINUTE;
-let MILLIS_IN_DAY = exports.MILLIS_IN_DAY = 24 * MILLIS_IN_HOUR;
+const {Utils} = require("utils");
+
+const MILLIS_IN_SECOND = exports.MILLIS_IN_SECOND = 1000;
+const MILLIS_IN_MINUTE = exports.MILLIS_IN_MINUTE = 60 * MILLIS_IN_SECOND;
+const MILLIS_IN_HOUR = exports.MILLIS_IN_HOUR = 60 * MILLIS_IN_MINUTE;
+const MILLIS_IN_DAY = exports.MILLIS_IN_DAY = 24 * MILLIS_IN_HOUR;
 
 let Downloader =
 /**
  * Creates a new downloader instance.
- * @param {Function} dataSource  Function that will yield downloadable objects
- *                               on each check
- * @param {Integer} initialDelay  Number of milliseconds to wait before the
- *                                 first check
- * @param {Integer} checkInterval  Interval between the checks
+ * @param {Function} dataSource
+ *   Function that will yield downloadable objects on each check
+ * @param {number} initialDelay
+ *   Number of milliseconds to wait before the first check
+ * @param {number} checkInterval
+ *   Interval between the checks
  * @constructor
  */
 exports.Downloader = function(dataSource, initialDelay, checkInterval)
 {
   this.dataSource = dataSource;
   this._timer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
   this._timer.initWithCallback(() =>
   {
     this._timer.delay = checkInterval;
     this._doCheck();
@@ skipping 15 matching lines @@
 
   /**
    * Function that will yield downloadable objects on each check.
    * @type {Function}
    */
   dataSource: null,
 
   /**
    * Maximal time interval that the checks can be left out until the soft
    * expiration interval increases.
-   * @type {Integer}
+   * @type {number}
    */
   maxAbsenceInterval: 1 * MILLIS_IN_DAY,
 
   /**
    * Minimal time interval before retrying a download after an error.
-   * @type {Integer}
+   * @type {number}
    */
   minRetryInterval: 1 * MILLIS_IN_DAY,
 
   /**
    * Maximal allowed expiration interval, larger expiration intervals will be
    * corrected.
-   * @type {Integer}
+   * @type {number}
    */
   maxExpirationInterval: 14 * MILLIS_IN_DAY,
 
   /**
    * Maximal number of redirects before the download is considered as failed.
-   * @type {Integer}
+   * @type {number}
    */
   maxRedirects: 5,
 
   /**
    * Called whenever expiration intervals for an object need to be adapted.
    * @type {Function}
    */
   onExpirationChange: null,
 
   /**
@@ skipping 19 matching lines @@
    * Checks whether anything needs downloading.
    */
   _doCheck()
   {
     let now = Date.now();
     for (let downloadable of this.dataSource())
     {
       if (downloadable.lastCheck &&
           now - downloadable.lastCheck > this.maxAbsenceInterval)
       {
-        // No checks for a long time interval - user must have been
-        // offline, e.g.  during a weekend. Increase soft expiration
-        // to prevent load peaks on the server.
+        // No checks for a long time interval - user must have been offline,
+        // e.g.  during a weekend. Increase soft expiration to prevent load
+        // peaks on the server.
         downloadable.softExpiration += now - downloadable.lastCheck;
       }
       downloadable.lastCheck = now;
 
       // Sanity check: do expiration times make sense? Make sure people changing
       // system clock don't get stuck with outdated subscriptions.
       if (downloadable.hardExpiration - now > this.maxExpirationInterval)
         downloadable.hardExpiration = now + this.maxExpirationInterval;
       if (downloadable.softExpiration - now > this.maxExpirationInterval)
         downloadable.softExpiration = now + this.maxExpirationInterval;
 
       // Notify the caller about changes to expiration parameters
       if (this.onExpirationChange)
         this.onExpirationChange(downloadable);
 
       // Does that object need downloading?
       if (downloadable.softExpiration > now &&
           downloadable.hardExpiration > now)
+      {
         continue;
+      }
 
       // Do not retry downloads too often
       if (downloadable.lastError &&
           now - downloadable.lastError < this.minRetryInterval)
+      {
         continue;
+      }
 
       this._download(downloadable, 0);
     }
   },
 
   /**
    * Stops the periodic checks.
    */
   cancel()
   {
     this._timer.cancel();
   },
 
   /**
    * Checks whether an address is currently being downloaded.
-   * @param {String} url
-   * @return {Boolean}
+   * @param {string} url
+   * @return {boolean}
    */
   isDownloading(url)
   {
     return url in this._downloading;
   },
 
   /**
    * Starts downloading for an object.
    * @param {Downloadable} downloadable
    */
   download(downloadable)
   {
     // Make sure to detach download from the current execution context
     Utils.runAsync(this._download.bind(this, downloadable, 0));
   },
 
   /**
    * Generates the real download URL for an object by appending various
    * parameters.
    * @param {Downloadable} downloadable
-   * @return {String}
+   * @return {string}
    */
   getDownloadUrl(downloadable)
   {
-    let {addonName, addonVersion, application, applicationVersion,
-         platform, platformVersion} = require("info");
+    const {addonName, addonVersion, application, applicationVersion,
+           platform, platformVersion} = require("info");
     let url = downloadable.redirectURL || downloadable.url;
     if (url.indexOf("?") >= 0)
       url += "&";
     else
       url += "?";
     // We limit the download count to 4+ to keep the request anonymized
     let {downloadCount} = downloadable;
     if (downloadCount > 4)
       downloadCount = "4+";
     url += "addonName=" + encodeURIComponent(addonName) +
@@ skipping 31 matching lines @@
                      "Download address: " + downloadUrl + "\n" +
                      "Channel status: " + channelStatus + "\n" +
                      "Server response: " + responseStatus);
 
       if (this.onDownloadError)
       {
         // Allow one extra redirect if the error handler gives us a redirect URL
         let redirectCallback = null;
         if (redirects <= this.maxRedirects)
         {
-          redirectCallback = (url) =>
+          redirectCallback = url =>
           {
             downloadable.redirectURL = url;
             this._download(downloadable, redirects + 1);
           };
         }
 
         this.onDownloadError(downloadable, downloadUrl, error, channelStatus,
                              responseStatus, redirectCallback);
       }
     }.bind(this);
@@ skipping 69 matching lines @@
     request.send(null);
 
     this._downloading[downloadable.url] = true;
     if (this.onDownloadStarted)
       this.onDownloadStarted(downloadable);
   },
 
   /**
    * Produces a soft and a hard expiration interval for a given supplied
    * expiration interval.
-   * @param {Integer} interval
+   * @param {number} interval
    * @return {Array} soft and hard expiration interval
    */
   processExpirationInterval(interval)
   {
     interval = Math.min(Math.max(interval, 0), this.maxExpirationInterval);
     let soft = Math.round(interval * (Math.random() * 0.4 + 0.8));
     let hard = interval * 2;
     let now = Date.now();
     return [now + soft, now + hard];
   }
 };
 
 /**
  * An object that can be downloaded by the downloadable
- * @param {String} url  URL that has to be requested for the object
+ * @param {string} url  URL that has to be requested for the object
  * @constructor
  */
 let Downloadable = exports.Downloadable = function Downloadable(url)
 {
   this.url = url;
 };
 Downloadable.prototype =
 {
   /**
    * URL that has to be requested for the object.
-   * @type {String}
+   * @type {string}
    */
   url: null,
 
   /**
    * URL that the download was redirected to if any.
-   * @type {String}
+   * @type {string}
    */
   redirectURL: null,
 
   /**
    * Time of last download error or 0 if the last download was successful.
-   * @type {Integer}
+   * @type {number}
    */
   lastError: 0,
 
   /**
    * Time of last check whether the object needs downloading.
-   * @type {Integer}
+   * @type {number}
    */
   lastCheck: 0,
 
   /**
    * Object version corresponding to the last successful download.
-   * @type {Integer}
+   * @type {number}
    */
   lastVersion: 0,
 
   /**
    * Soft expiration interval, will increase if no checks are performed for a
    * while.
-   * @type {Integer}
+   * @type {number}
    */
   softExpiration: 0,
 
   /**
    * Hard expiration interval, this is fixed.
-   * @type {Integer}
+   * @type {number}
    */
   hardExpiration: 0,
 
   /**
    * Number indicating how often the object was downloaded.
-   * @type {Integer}
+   * @type {number}
    */
   downloadCount: 0
 };