Fixed host list cache and "no hosts" icon flash

remoting/webapp/host_list.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @fileoverview
  * Class representing the host-list portion of the home screen UI.
  */
 
 'use strict';
@@ skipping 98 matching lines @@
   var that = this;
   /** @param {string} token The OAuth2 token. */
   var getHosts = function(token) {
     var headers = { 'Authorization': 'OAuth ' + token };
     remoting.xhr.get(
         'https://www.googleapis.com/chromoting/v1/@me/hosts',
         parseHostListResponse, '', headers);
   };
   /** @param {remoting.Error} error */
   var onError = function(error) {
+    that.hosts_ = [];
     that.lastError_ = error;
     onDone(false);
   };
-  this.hosts_ = [];
-  this.lastError_ = '';

[Wez, 2012/07/11 20:48:10]

Are you relying on the fact that lastError_ will only be checked if
onDone(false) is called, i.e. in the onError() case?

[Jamie, 2012/07/11 20:53:11]

No, I think your next comment is correct, and I should be resetting it when we
get a response.

   remoting.oauth2.callWithToken(getHosts, onError);
 };
 
 /**
  * Handle the results of the host list request.  A success response will
  * include a JSON-encoded list of host descriptions, which we display if we're
  * able to successfully parse it.
  *
  * @param {function(boolean):void} onDone The callback passed to |refresh|.
  * @param {XMLHttpRequest} xhr The XHR object for the host list request.
  * @return {void} Nothing.
  * @private
  */
 remoting.HostList.prototype.parseHostListResponse_ = function(onDone, xhr) {
+  this.hosts_ = [];

[Wez, 2012/07/11 20:48:10]

I think you need to clear lastError_ here to avoid the onDone() call later on
getting confused by seeing lastError_ values from previous failures?

[Jamie, 2012/07/11 20:53:11]

Done.

   try {
     if (xhr.status == 200) {
       var response =
           /** @type {{data: {items: Array}}} */ jsonParseSafe(xhr.responseText);
       if (response && response.data) {
         if (response.data.items) {
           this.hosts_ = response.data.items;
           /**
            * @param {remoting.Host} a
            * @param {remoting.Host} b
            */
           var cmp = function(a, b) {
             if (a.status < b.status) {
               return 1;
             } else if (b.status < a.status) {
               return -1;
             }
             return 0;
           };
           this.hosts_ = /** @type {Array} */ this.hosts_.sort(cmp);
-        } else {
-          this.hosts_ = [];
         }
       } else {
+        this.lastError_ = remoting.Error.UNEXPECTED;
         console.error('Invalid "hosts" response from server.');
       }
     } else {
       // Some other error.
       console.error('Bad status on host list query: ', xhr);
       if (xhr.status == 401) {
         this.lastError_ = remoting.Error.AUTHENTICATION_FAILED;
       } else if (xhr.status == 503) {
         this.lastError_ = remoting.Error.SERVICE_UNAVAILABLE;
       } else {
@@ skipping 155 matching lines @@
   }
 }
 
 /**
  * Key name under which Me2Me hosts are cached.
  */
 remoting.HostList.HOSTS_KEY = 'me2me-cached-hosts';
 
 /** @type {remoting.HostList} */
 remoting.hostList = null;