Change getDevices to use a DeviceCallback.

chrome/renderer/resources/extensions/experimental.bluetooth_custom_bindings.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.
 
 // Custom bindings for the Bluetooth API.
 
 var chromeHidden = requireNative('chrome_hidden').GetChromeHidden();
 var sendRequest = require('sendRequest').sendRequest;
 var lastError = require('last_error');
 
 // Use custom bindings to create an undocumented event listener that will
 // receive events about device discovery and call the event listener that was
 // provided with the request to begin discovery.
 chromeHidden.registerCustomHook('experimental.bluetooth', function(api) {
   var apiFunctions = api.apiFunctions;
 
   chromeHidden.bluetooth = {};
+
   chromeHidden.bluetooth.deviceDiscoveredHandler = null;
   chromeHidden.bluetooth.onDeviceDiscovered =
       new chrome.Event("experimental.bluetooth.onDeviceDiscovered");
-
   function clearDeviceDiscoveredHandler() {
     chromeHidden.bluetooth.onDeviceDiscovered.removeListener(
         chromeHidden.bluetooth.deviceDiscoveredHandler);
     chromeHidden.bluetooth.deviceDiscoveredHandler = null;
   }
-
   apiFunctions.setHandleRequest('startDiscovery',
       function() {
         var args = arguments;
         if (args.length > 0 && args[0] && args[0].deviceCallback) {
           chromeHidden.bluetooth.deviceDiscoveredHandler =
               args[0].deviceCallback;
           chromeHidden.bluetooth.onDeviceDiscovered.addListener(
               chromeHidden.bluetooth.deviceDiscoveredHandler);
           sendRequest(this.name,
                       args,
@@ skipping 13 matching lines @@
         if (chrome.runtime.lastError) {
           clearDeviceDiscoveredHandler();
           return;
         }
       });
   apiFunctions.setHandleRequest('stopDiscovery',
       function() {
         clearDeviceDiscoveredHandler();
         sendRequest(this.name, arguments, this.definition.parameters);
       });
+
+  chromeHidden.bluetooth.deviceSearchResultHandler = null;
+  chromeHidden.bluetooth.onDeviceSearchResult =
+      new chrome.Event("experimental.bluetooth.onDeviceSearchResult");
+  apiFunctions.setHandleRequest('getDevices',
+      function() {
+        var args = arguments;
+        if (args.length > 0 && args[0] && args[0].deviceCallback) {
+          chromeHidden.bluetooth.deviceSearchResultHandler =
+              args[0].deviceCallback;
+          chromeHidden.bluetooth.onDeviceSearchResult.addListener(
+              chromeHidden.bluetooth.deviceSearchResultHandler);

[asargent_no_longer_on_chrome, 2012/09/11 17:42:56]

It looks like your intention is to only handle a single outstanding request to
getDevices at a time from a given script context, but you don't seem to enforce
that here, so you can clobber the reference to the outstanding call's listener,
and then in setCustomCallback you'll remove the wrong one. 

I think you want to check if deviceSearchResultHandler is null and return an
error if it isn't. 

Alternatively, if you wanted to allow multiple outstanding calls to getDevices
(does the C++ code support that?) you could keep a map of references to
listeners keyed by request id. I believe the request id is hung off the request
object that your setHandleRequest and setCustomCallback gets called with. 

[bryeung, 2012/09/11 18:37:30]

Great catch.

I'm fine with disallowing concurrent calls to these methods.  I've updated the
code and added a test for the getDevices case.

+          sendRequest(this.name,
+                      args,
+                      this.definition.parameters,
+                      {customCallback:this.customCallback});
+        } else {
+          if (typeof(args[args.length-1]) == "function") {
+            var callback = args[args.length-1];
+            lastError.set("deviceCallback is required in the options object");
+            callback();
+            return;
+          }
+        }
+      });
+  apiFunctions.setCustomCallback('getDevices',
+      function(name, request, response) {
+        chromeHidden.bluetooth.onDeviceSearchResult.removeListener(
+            chromeHidden.bluetooth.deviceSearchResultHandler);
+        chromeHidden.bluetooth.deviceSearchResultHandler = null;
+      });
 });