bluetooth: Add DeviceChanged logging in Device service.

chrome/browser/resources/bluetooth_internals/bluetooth_internals.js

 // Copyright 2016 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.
 
 /**
  * Javascript for bluetooth_internals.html, served from
  *     chrome://bluetooth-internals/.
  */
 
-/**
- * The implementation of AdapterClient in
- *     device/bluetooth/public/interfaces/adapter.mojom.
- */
-var AdapterClient = function() {};
-AdapterClient.prototype = {
-  /**
-   * Prints added device to console.
-   * @param {!bluetoothDevice.DeviceInfo} device
-   */
-  deviceAdded: function(device) { console.log('Device added', device); },
-
-  /**
-   * Prints removed device to console.
-   * @param {!bluetoothDevice.DeviceInfo} device
-   */
-  deviceRemoved: function(device) { console.log('Device removed', device); }
-};
-
 (function() {
   var adapter, adapterClient, bluetoothAdapter, bluetoothDevice, connection;
 
+  // Dictionary for address->Device cache.
+  var devices = new Map();
+
+  // Data model for a cached device.
+  var Device = function(info) { this.info = info; };

[dpapad, 2016/10/20 21:22:01]

@constructor
@param {!bluetoothDevice.DeviceInfo} info

[mbrunson, 2016/10/20 22:00:35]

Done.

+
+  /**
+   * The implementation of AdapterClient in
+   *     device/bluetooth/public/interfaces/adapter.mojom.
+   */
+  var AdapterClient = function() {};

[dpapad, 2016/10/20 21:22:01]

Is there a good reason that the |devices| map is not a member of AdapterClient?

var AdapterClient = function() {
  this.devices = new Map();
};

If you also follow my suggestion at the end of this file, you can make this
field private (by renaming to devices_).

[mbrunson, 2016/10/20 22:00:35]

Originally, I was thinking to just have the UI-related code access the |devices|
map directly.

I can make it a private member of AdapterClient, and I could just make a
function that generates the needed HTML. That sounds more organized to me.
Thanks.

+  AdapterClient.prototype = {
+    /**
+     * Logs added device to console and caches the device info.
+     * @param {!bluetoothDevice.DeviceInfo} device
+     */
+    deviceAdded: function(deviceInfo) {
+      console.log('Device added', deviceInfo);
+      devices.set(deviceInfo.address, new Device(deviceInfo));
+    },
+
+    /**
+     * Logs removed device to console and removes the cached device.
+     * @param {!bluetoothDevice.DeviceInfo} device
+     */
+    deviceRemoved: function(deviceInfo) {
+      console.log('Device removed', deviceInfo);
+      devices.delete(deviceInfo.address);
+    },
+
+    /**
+     * Logs changed device info to console and updates the cached device.
+     * @param {!bluetoothDevice.DeviceInfo} deviceInfo
+     */
+    deviceChanged: function(deviceInfo) {
+      console.log(new Date(), deviceInfo);
+      devices.get(deviceInfo.address).info = deviceInfo;

[dpapad, 2016/10/20 21:22:01]

Should probably assert that the item was found in the map before refering to
.info.

[mbrunson, 2016/10/20 22:00:35]

Done.

+    }
+  };
+
   /**
    * TODO(crbug.com/652361): Move to shared location.
    * Helper to convert callback-based define() API to a promise-based API.
    * @param {!Array<string>} moduleNames
    * @return {!Promise}
    */
   function importModules(moduleNames) {
     return new Promise(function(resolve, reject) {
       define(moduleNames, function(var_args) {
         resolve(Array.prototype.slice.call(arguments, 0));
@@ skipping 36 matching lines @@
       adapter = connection.bindHandleToProxy(response.adapter,
                                              bluetoothAdapter.Adapter);
 
       // Create a message pipe and bind one end to client
       // implementation and the other to the Adapter service.
       adapterClient = new AdapterClient();
       adapter.setClient(connection.bindStubDerivedImpl(adapterClient));
     });
   }
 
-  /**
-   * Prints device info from the device service.
-   * @param {!bluetoothDevice.DeviceInfo} deviceInfo the device for which to
-   *     get the information.
-   * @return {!Promise} resolves if device service is retrieved, rejects
-   *     otherwise.
-   */
-  function logDevice(deviceInfo) {
-    return adapter.getDevice(deviceInfo.address).then(function(response) {
-        var deviceHandle = response.device;
-        if (!deviceHandle) {
-          throw new Error(deviceInfo.name_for_display + ' cannot be found.');
-        }
-
-        var device = connection.bindHandleToProxy(
-              deviceHandle, bluetoothDevice.Device);
-        return device.getInfo();
-      }).then(function(response) {
-        console.log(deviceInfo.name_for_display, response.info);
-      });
-  }
-
   document.addEventListener('DOMContentLoaded', function() {
     initializeProxies()
       .then(function() { return adapter.getInfo(); })
       .then(function(response) { console.log('adapter', response.info); })
       .then(function() { return adapter.getDevices(); })
       .then(function(response) {
-        var devices = response.devices;
-        console.log('devices', devices.length);
+        console.log('devices', response.devices.length);
 
-        return Promise.all(devices.map(logDevice));
+        response.devices.forEach(function(deviceInfo) {
+          devices.set(deviceInfo.address, new Device(deviceInfo));

[dpapad, 2016/10/20 21:22:01]

Is this necessary to initialize local state? If so, can we simply call
adapter.deviceAdded(deviceInfo) here.

[mbrunson, 2016/10/20 22:00:35]

Done.

+          console.log(deviceInfo.name_for_display, deviceInfo);
+        });
       })
       .catch(function(error) { console.error(error); });
   });
 })();