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';

 module.metadata = {

   'stability': 'experimental'

 };

 let { request: hostReq, response: hostRes } = require('./host');

 let { defer: async } = require('../lang/functional');

 let { defer } = require('../core/promise');

 let { emit: emitSync, on, off } = require('../event/core');

 let { uuid } = require('../util/uuid');

 let emit = async(emitSync);

 // Map of IDs to deferreds

 let requests = new Map();

 // May not be necessary to wrap this in `async`

 // once promises are async via bug 881047

 let receive = async(function ({data, id, error}) {

   let request = requests.get(id);

   if (request) {

     if (error) request.reject(error);

     else request.resolve(clone(data));

     requests.delete(id);

   }

 });

 on(hostRes, 'data', receive);

 /*

  * Send is a helper to be used in client APIs to send

  * a request to host

  */

 function send (eventName, data) {

   let id = uuid();

   let deferred = defer();

   requests.set(id, deferred);

   emit(hostReq, 'data', {

     id: id,

     data: clone(data),

     event: eventName

   });

   return deferred.promise;

 }

 exports.send = send;

 /*

  * Implement internal structured cloning algorithm in the future?

  * http://www.whatwg.org/specs/web-apps/current-work/multipage/common-dom-interfaces.html#internal-structured-cloning-algorithm

  */

 function clone (obj) JSON.parse(JSON.stringify(obj || {}))