Update info module and make updater use the new downloader module

lib/updater.js

 /*
  * This file is part of Adblock Plus <http://adblockplus.org/>,
  * Copyright (C) 2006-2013 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/>.
  */
 
 let {Prefs} = require("prefs");
+let {Downloader, Downloadable, MILLIS_IN_HOUR} = require("downloader");
+
 let updateUrl = (_appInfo.developmentBuild ? Prefs.update_url_devbuild : Prefs.update_url_release);
-updateUrl = updateUrl.replace(/%NAME%/g, encodeURIComponent(_appInfo.name))
-                     .replace(/%ID%/g, encodeURIComponent(_appInfo.id))
-                     .replace(/%VERSION%/g, encodeURIComponent(_appInfo.version))
-                     .replace(/%APP%/g, encodeURIComponent(_appInfo.platform));
+updateUrl = updateUrl.replace(/%NAME%/g, encodeURIComponent(_appInfo.name));
 
-const HOURS_TO_MILLIS = 60 * 60 * 1000;
-const MIN_CHECK_INTERVAL = 18 * HOURS_TO_MILLIS;
-const MAX_CHECK_INTERVAL = 30 * HOURS_TO_MILLIS;
+let callback = null;
 
+const INITIAL_DELAY = 0.1 * MILLIS_IN_HOUR;
+const CHECK_INTERVAL = 1 * MILLIS_IN_HOUR;
+const EXPIRATION_INTERVAL = 24 * MILLIS_IN_HOUR;
 const TYPE_AUTOMATIC = 0;
 const TYPE_MANUAL = 1;
 
-let checkForUpdates = exports.checkForUpdates = function checkForUpdates(forceCheck, callback)
+let downloader = new Downloader(getDownloadables, INITIAL_DELAY, CHECK_INTERVAL);
+downloader.onExpirationChange = onExpirationChange;
+downloader.onDownloadSuccess = onDownloadSuccess;
+downloader.onDownloadError = onDownloadError;
+
+function getDownloadable(forceCheck)
 {
-  let now = Date.now();
-  if (!forceCheck && now < Prefs.next_update_check)
+  let url = updateUrl.replace(/%TYPE%/g, forceCheck ? TYPE_MANUAL : TYPE_AUTOMATIC);
+  let downloadable = new Downloadable(url);
+  downloadable.lastError = Prefs.update_last_error;
+  downloadable.lastCheck = Prefs.update_last_check;
+  downloadable.softExpiration = Prefs.update_soft_expiration;
+  downloadable.hardExpiration = Prefs.update_hard_expiration;
+  return downloadable;
+}
+
+function getDownloadables()
+{
+  yield getDownloadable(false);
+}
+
+function onExpirationChange(downloadable)
+{
+  Prefs.update_last_check = downloadable.lastCheck;
+  Prefs.update_soft_expiration = downloadable.softExpiration;
+  Prefs.update_hard_expiration = downloadable.hardExpiration;
+}
+
+function onDownloadSuccess(downloadable, responseText, errorCallback, redirectCallback)
+{
+  Prefs.update_last_error = 0;
+  [Prefs.update_soft_expiration, Prefs.update_hard_expiration] = downloader.processExpirationInterval(EXPIRATION_INTERVAL);
+
+  try
   {
-    if (Prefs.next_update_check - now > MAX_CHECK_INTERVAL)
-      Prefs.next_update_check = now + MAX_CHECK_INTERVAL;
+    let data = JSON.parse(responseText);
+    let updateInfo = null;
+    if (_appInfo.name in data)
+      updateInfo = data[_appInfo.name];
+    else if (_appInfo.name + "/" + _appInfo.application in data)
+      updateInfo = data[_appInfo.name + "/" + _appInfo.application];
 
-    window.setTimeout(checkForUpdates, Prefs.next_update_check - now);
-    return;
+    if (updateInfo && "version" in updateInfo && "url" in updateInfo &&
+        Services.vc.compare(updateInfo.version, _appInfo.version) > 0)
+    {
+      if (updateInfo.url.indexOf("https://") != 0)
+        throw new Error("Invalid update URL, HTTPS is mandatory for updates");
+      _triggerEvent("updateAvailable", updateInfo.url);
+    }
+    if (callback)
+      callback(null);
+  }
+  catch (e)
+  {
+    Cu.reportError(e);
+    errorCallback(e);
   }
 
-  Prefs.next_update_check = now + MIN_CHECK_INTERVAL +
-      Math.random() * (MAX_CHECK_INTERVAL - MIN_CHECK_INTERVAL);
-  if (!forceCheck)
-    window.setTimeout(checkForUpdates, Prefs.next_update_check - now);
-
-  let url = updateUrl.replace(/%TYPE%/g, forceCheck ? TYPE_MANUAL : TYPE_AUTOMATIC);
-  let request = new XMLHttpRequest();
-  request.open("GET", url);
-  request.addEventListener("load", function()
-  {
-    try
-    {
-      let data = JSON.parse(request.responseText);
-      let updateInfo = null;
-      if (_appInfo.name in data)
-        updateInfo = data[_appInfo.name];
-      else if (_appInfo.name + "/" + _appInfo.platform in data)
-        updateInfo = data[_appInfo.name + "/" + _appInfo.platform];
-
-      if (updateInfo && "version" in updateInfo && "url" in updateInfo &&
-          Services.vc.compare(updateInfo.version, _appInfo.version) > 0)
-      {
-        if (updateInfo.url.indexOf("https://") != 0)
-          throw new Error("Invalid update URL, HTTPS is mandatory for updates");
-        _triggerEvent("updateAvailable", updateInfo.url);
-      }
-      if (callback)
-        callback(null);
-    }
-    catch (e)
-    {
-      Cu.reportError(e);
-      if (callback)
-        callback(e);
-    }
-  }, false);
-
-  request.addEventListener("error", function()
-  {
-    let e = new Error("Update check failed (channel status " + request.channel.status + ")");
-    Cu.reportError(e);
-    if (callback)
-      callback(e);
-  }, false);
-
-  request.send(null);
+  callback = null;
 }
 
-window.setTimeout(checkForUpdates, 0.1 * HOURS_TO_MILLIS);
+function onDownloadError(downloadable, downloadURL, error, channelStatus, responseStatus, redirectCallback)
+{
+  Prefs.update_last_error = Date.now();
+  if (callback)
+    callback(error);
+  callback = null;
+}
+
+let checkForUpdates = exports.checkForUpdates = function checkForUpdates(_callback)
+{
+  callback = _callback;
+  downloader.download(getDownloadable(true));
+}