Issue 2325 - Add a way to set settings in libadblockplus for FRP and automatic updates

lib/prefs.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2015 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 23 matching lines @@
   subscriptions_exceptionsurl: "https://easylist-downloads.adblockplus.org/exceptionrules.txt",
   documentation_link: "https://adblockplus.org/redirect?link=%LINK%&lang=%LANG%",
   update_url_release: "https://update.adblockplus.org/%NAME%/update.json?type=%TYPE%",
   update_url_devbuild: "https://adblockplus.org/devbuilds/%NAME%/update.json?type=%TYPE%",
   update_last_check: 0,
   update_last_error: 0,
   update_soft_expiration: 0,
   update_hard_expiration: 0,
   currentVersion: "0.0",
   notificationdata: {},
-  notificationurl: "https://notification.adblockplus.org/notification.json"
+  notificationurl: "https://notification.adblockplus.org/notification.json",
+  suppress_first_run_page: false,
+  disable_auto_updates: false
 };
 
+let preconfigurable = ["suppress_first_run_page", "disable_auto_updates"];
+
 let values = Object.create(defaults);
 let path = _fileSystem.resolve("prefs.json");
 let listeners = [];
 let isDirty = false;
 let isSaving = false;
 
 function defineProperty(key)
 {
   Object.defineProperty(Prefs, key,
   {
@@ skipping 11 matching lines @@
 
       for (let listener of listeners)
         listener(key);
     },
     enumerable: true
   });
 }
 
 function load()
 {
+  // Set default prefs based on _preconfiguredPrefs
+  for (let key in _preconfiguredPrefs)
+  {
+    if (preconfigurable.indexOf(key) != -1)
+    {
+      if (typeof _preconfiguredPrefs[key] != typeof defaults[key])

[Felix Dahlke, 2015/06/12 11:55:35]

Don't think we need to check for this - we don't do it on other platforms
either.

[Oleksandr, 2015/06/12 12:29:59]

Done.

+        throw new Error("Attempt to change preference type through preconfiguration");
+      defaults[key] = _preconfiguredPrefs[key];

[Felix Dahlke, 2015/06/12 11:55:35]

Was about to complain that this isn't necessary, but it actually could be. If we
don't this, we'd be introducing a footgun:

defaults = {x: 1}
preconfiguredPrefs = {x: 2}
Prefs.x = 1;
restoreDefault("x");
Prefs.x == 2; // Nope, it's 1

Now, restoreDefault() doesn't actually exist IIRC, but in Firefox we have it,
and if we add it in libdablockplus as well, our feet are in danger.

But I think we can solve this by simply modifying defaults once, rather than
messing with both defaults and values. In particular:

1. We move this out of load(), where it probably doesn't really belong, and put
it right before the `for (let key in defaults)` loop below. And then we just do
this:

for (let key in _preconfiguredPrefs)
  if (preconfigurable.indexOf(key) != -1)
    defaults[key] = _preconfiguredPrefs[key];

2. We will have to move the initialisation of "values" down there, before the
load() call.

IMHO it's simpler that way. We just modify defaults to begin with, the rest of
the code works the same as before.

[Oleksandr, 2015/06/12 12:29:59]

Done.

+      values[key] = _preconfiguredPrefs[key];
+    }
+  }
+
   _fileSystem.read(path, function(result)
   {
     // prefs.json is expected to be missing, ignore errors reading file
     if (!result.error)
     {
       try
       {
         let data = JSON.parse(result.content);
         for (let key in data)
           if (key in defaults)
@@ skipping 40 matching lines @@
     let index = listeners.indexOf(listener);
     if (index >= 0)
       listeners.splice(index, 1);
   },
 };
 
 for (let key in defaults)
   defineProperty(key);
 
 load();