remoting/webapp/base/js/experiments.js

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 /**
   6  * @fileoverview
   7  * Class for enabling experimental features.
   8  */
   9
  10 'use strict';
  11
  12 /** @suppress {duplicate} */
  13 var remoting = remoting || {};
  14
  15 (function() {
  16
  17 var kExperimentsStorageName = 'remoting-experiments';
  18 var ACTIVE_FIELD_TRIALS = {'ChromotingQUIC': 'quic', 'ChromotingVP9': 'vp9'};
  19
  20 /**
  21  * @param {Array.<string>} list
  22  */
  23 function save(list) {
  24   var storageMap = {};
  25   storageMap[kExperimentsStorageName] = list;
  26   chrome.storage.local.set(storageMap);
  27 };
  28
  29 /** @type {Object} */
  30 remoting.experiments = {};
  31
  32 /**
  33  * Enables an experiment.
  34  *
  35  * @param {string} experiment to enable.
  36  */
  37 remoting.experiments.enable = function(experiment) {
  38   remoting.experiments.get().then(function(/** Array.<string> */list) {
  39     if (list.indexOf(experiment) == -1) {
  40       list.push(experiment);
  41       save(list);
  42     }
  43   });
  44 };
  45
  46 /**
  47  * Disables an experiment.
  48  *
  49  * @param {string} experiment to disable.
  50  */
  51 remoting.experiments.disable = function(experiment) {
  52   remoting.experiments.get().then(function(/** Array.<string> */list) {
  53     list = list.filter(function(e) { return e !== experiment; });
  54     save(list);
  55   });
  56 };
  57
  58 /**
  59  * Determines if the field-trial is enabled for this session.
  60  *
  61  * @param {string} trialName The FieldTrial to check for enabling.
  62  * @return {Promise}
  63  */
  64 function getTrialState(trialName) {
  65   var deferred = new base.Deferred();
  66   chrome.metricsPrivate.getFieldTrial(trialName,
  67                                       function(/** string */ group) {
  68                                         if (group == 'Enabled') {
  69                                           deferred.resolve(true);
  70                                         } else {
  71                                           deferred.resolve(false);
  72                                         }
  73                                       });
  74   return deferred.promise();
  75 };
  76
  77 /**
  78  * Returns list of all enabled experiments.
  79  * @return {Promise}
  80  */
  81 remoting.experiments.get = function() {
  82
  83   var localStorageList = new Promise(function(resolve, reject) {
  84     chrome.storage.local.get(kExperimentsStorageName, function(items) {
  85       /** @type {Array<string>} */
  86       var experiments = new Array();
  87       if (items.hasOwnProperty(kExperimentsStorageName)) {
  88         experiments = /** @type {Array<string>} */
  89             (items[kExperimentsStorageName]);
  90       }
  91       resolve(experiments);
  92     });
  93   });
  94
  95   var trialNames = Object.keys(ACTIVE_FIELD_TRIALS);
  96
  97   return Promise.all([localStorageList].concat(
  98                          trialNames.map(function(/** string */ trialName) {
  99                            return getTrialState(trialName);
 100                          })))
 101       .then(function(results) {
 102         /** @type {Array<string>} */
 103         var list = results[0];
 104         for (var i = 0; i < trialNames.length; ++i) {
 105           if (results[i + 1]) {
 106             list.push(ACTIVE_FIELD_TRIALS[trialNames[i]]);
 107           }
 108         }
 109         return list;
 110       });
 111 };
 112
 113 })();