The Tor Browser / file revision

 /* This Source Code Form is subject to the terms of the Mozilla Public

  * License, v. 2.0. If a copy of the MPL was not distributed with this

  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

 "use strict";

 const { windows, isBrowser, isInteractive, isDocumentLoaded,

         getOuterId } = require("../window/utils");

 const { InputPort } = require("./system");

 const { lift, merges, foldp, keepIf, start, Input } = require("../event/utils");

 const { patch } = require("diffpatcher/index");

 const { Sequence, seq, filter, object, pairs } = require("../util/sequence");

 // Create lazy iterators from the regular arrays, although

 // once https://github.com/mozilla/addon-sdk/pull/1314 lands

 // `windows` will be transforme to lazy iterators.

 // When iterated over belowe sequences items will represent

 // state of windows at the time of iteration.

 const opened = seq(function*() {

   const items = windows("navigator:browser", {includePrivates: true});

   for (let item of items) {

       yield [getOuterId(item), item];

   }

 });

 const interactive = filter(([_, window]) => isInteractive(window), opened);

 const loaded = filter(([_, window]) => isDocumentLoaded(window), opened);

 // Helper function that converts given argument to a delta.

 const Update = window => window && object([getOuterId(window), window]);

 const Delete = window => window && object([getOuterId(window), null]);

 // Signal represents delta for last top level window close.

 const LastClosed = lift(Delete,

                         keepIf(isBrowser, null,

                                new InputPort({topic: "domwindowclosed"})));

 exports.LastClosed = LastClosed;

 const windowFor = document => document && document.defaultView;

 // Signal represent delta for last top level window document becoming interactive.

 const InteractiveDoc = new InputPort({topic: "chrome-document-interactive"});

 const InteractiveWin = lift(windowFor, InteractiveDoc);

 const LastInteractive = lift(Update, keepIf(isBrowser, null, InteractiveWin));

 exports.LastInteractive = LastInteractive;

 // Signal represent delta for last top level window loaded.

 const LoadedDoc = new InputPort({topic: "chrome-document-loaded"});

 const LoadedWin = lift(windowFor, LoadedDoc);

 const LastLoaded = lift(Update, keepIf(isBrowser, null, LoadedWin));

 exports.LastLoaded = LastLoaded;

 const initialize = input => {

   if (!input.initialized) {

     input.value = object(...input.value);

     Input.start(input);

     input.initialized = true;

   }

 };

 // Signal represents set of top level interactive windows, updated any

 // time new window becomes interactive or one get's closed.

 const Interactive = foldp(patch, interactive, merges([LastInteractive,

                                                       LastClosed]));

 Interactive[start] = initialize;

 exports.Interactive = Interactive;

 // Signal represents set of top level loaded window, updated any time

 // new window becomes interactive or one get's closed.

 const Loaded = foldp(patch, loaded, merges([LastLoaded, LastClosed]));

 Loaded[start] = initialize;

 exports.Loaded = Loaded;