Issue 6599 - Detect data corruption of storage.local

lib/subscriptionInit.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
@@ skipping 13 matching lines @@
        SpecialSubscription} =
   require("../adblockpluscore/lib/subscriptionClasses");
 const {FilterStorage} = require("../adblockpluscore/lib/filterStorage");
 const {FilterNotifier} = require("../adblockpluscore/lib/filterNotifier");
 const info = require("../buildtools/info");
 const {Prefs} = require("./prefs");
 const {Synchronizer} = require("../adblockpluscore/lib/synchronizer");
 const {Utils} = require("./utils");
 const {initNotifications} = require("./notificationHelper");
 const {updatesVersion} = require("../adblockplusui/lib/prefs");
-const {setUninstallURL} = require("./uninstall");
 
 let firstRun;
 let subscriptionsCallback = null;
+let reinitialized = false;
+let dataCorrupted = false;
 
 /**
  * If there aren't any filters, the default subscriptions are added.
  * However, if patterns.ini already did exist and/or any preference
  * is set to a non-default value, this indicates that this isn't the
  * first run, but something went wrong.
  *
  * This function detects the first run, and makes sure that the user
  * gets notified (on the first run page) if the data appears incomplete
  * and therefore will be reinitialized.
  */
 function detectFirstRun()
 {
   firstRun = FilterStorage.subscriptions.length == 0;
 
   if (firstRun && (!FilterStorage.firstRun || Prefs.currentVersion))
-    exports.reinitialized = true;
+    reinitialized = true;
 
   Prefs.currentVersion = info.addonVersion;
 }
 
 /**
  * Determines whether to add the default ad blocking subscription.
  * Returns true, if there are no filter subscriptions besides those
  * other subscriptions added automatically, and no custom filters.
  *
  * On first run, this logic should always result in true since there
@@ skipping 74 matching lines @@
 function supportsNotificationsWithButtons()
 {
   // Microsoft Edge (as of EdgeHTML 16) doesn't have the notifications API.
   // Opera gives an asynchronous error when buttons are provided (we cannot
   // detect that behavior without attempting to show a notification).
   if (!("notifications" in browser) || info.application == "opera")
     return false;
 
   // Firefox throws synchronously if the "buttons" option is provided.
   // If buttons are supported (i.e. on Chrome), this fails with
-  // a different error message due to missing required options.
+  // an asynchronous error due to missing required options.
   // https://bugzilla.mozilla.org/show_bug.cgi?id=1190681
   try
   {
-    browser.notifications.create({buttons: []});
+    browser.notifications.create({buttons: []}).catch(() => {});
   }
   catch (e)
   {
     if (e.toString().includes('"buttons" is unsupported'))
       return false;
   }
 
   return true;
 }
 
@@ skipping 77 matching lines @@
 
   // Show first run page or the updates page. The latter is only shown
   // on Chromium (since the current updates page announces features that
   // aren't new to Firefox users), and only if this version of the
   // updates page hasn't been shown yet.
   if (firstRun || info.platform == "chromium" &&
                   updatesVersion > Prefs.last_updates_page_displayed)
   {
     return Prefs.set("last_updates_page_displayed", updatesVersion).catch(() =>
     {
-      exports.dataCorrupted = true;
+      dataCorrupted = true;
     }).then(() =>
     {
       if (!Prefs.suppress_first_run_page)
       {
         // Always show the first run page if a data corruption was detected
-        // (either though failure of reading from or writing to storage.local).
+        // (either through failure of reading from or writing to storage.local).
         // The first run page notifies the user about the data corruption.
         let url;
-        if (firstRun || exports.dataCorrupted)
+        if (firstRun || dataCorrupted)
           url = "firstRun.html";
         else
           url = "updates.html";
         browser.tabs.create({url});
       }
     });
   }
 }
 
 Promise.all([
   FilterNotifier.once("load"),
-  Prefs.untilLoaded.catch(() => { exports.dataCorrupted = true; })
+  Prefs.untilLoaded.catch(() => { dataCorrupted = true; })
 ]).then(detectFirstRun)
   .then(getSubscriptions)
   .then(addSubscriptionsAndNotifyUser)
-  .then(setUninstallURL)
+  // We have to require the "uninstall" module on demand,
+  // as the "uninstall" module in turn requires this module.
+  .then(() => { require("./uninstall").setUninstallURL(); })
   .then(initNotifications);
 
 /**
- * Indicates whether the default filter subscriptions have been added
- * again because there weren't any subscriptions even though this wasn't
+ * Gets a value indicating whether the default filter subscriptions have been
+ * added again because there weren't any subscriptions even though this wasn't
  * the first run.
  *
- * @type {boolean}
- */
-exports.reinitialized = false;
-
-/**
- * Indicates whether a data corruption was detected.
- *
- * @type {boolean}
- */
-exports.dataCorrupted = false;

[kzar, 2018/04/25 14:38:12]

I just realised that this should probably be a getter instead. Otherwise if it's
required directly the value won't update and that might not be obvious.

[Sebastian Noack, 2018/04/25 14:46:23]

Doesn't strike me as a huge issue. But more importantly it is consistent with
"reinitialized", and I'd rather not make this a getter without making
"reinitialized" a getter as well, but then we are going down a rabbit hole of
unrelated changes (also considering adblockplusui that relies on those).

[kzar, 2018/04/25 14:57:04]

Well I agree about not randomly changing "reinitialized" here, but not about not
making "dataCorrupted" a getter. To my mind "dataCorrupted" could change when we
detect that the data has been corrupted, even if we don't have such a check
implemented yet. Your example of not wanting to change code already used
elsewhere to / from a getter is a good example why we should make this a getter
now.

[Sebastian Noack, 2018/04/25 17:08:56]

I disagree about only changing either of them. So I turned both now into a
getter. I added Thomas CC, so that he knows that he has to account for those
changes in adblockplusui. FWIW, I couldn't test the latest patch set yet, will
do once there is a version of adblockplusui, I can test it with.

+ * @return {boolean}
+ */
+exports.isReinitialized = () => reinitialized;
+
+/**
+ * Gets a value indicating whether a data corruption was detected.
+ *
+ * @return {boolean}
+ */
+exports.isDataCorrupted = () => dataCorrupted;
 
 /**
  * Sets a callback that is called with an array of subscriptions to be added
  * during initialization. The callback must return an array of subscriptions
  * that will effectively be added.
  *
  * @param {function} callback
  */
 exports.setSubscriptionsCallback = callback =>
 {
   subscriptionsCallback = callback;
 };