src/extensions/renderer/resources/serial_custom_bindings.js

   1 // Copyright 2014 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  * Custom bindings for the Serial API.
   7  *
   8  * The bindings are implemented by asynchronously delegating to the
   9  * serial_service module. The functions that apply to a particular connection
  10  * are delegated to the appropriate method on the Connection object specified by
  11  * the ID parameter.
  12  */
  13
  14 var binding = require('binding').Binding.create('serial');
  15 var context = requireNative('v8_context');
  16 var eventBindings = require('event_bindings');
  17 var utils = require('utils');
  18
  19 var serialServicePromise = function() {
  20   // getBackgroundPage is not available in unit tests so fall back to the
  21   // current page's serial_service module.
  22   if (!chrome.runtime.getBackgroundPage)
  23     return requireAsync('serial_service');
  24
  25   // Load the serial_service module from the background page if one exists. This
  26   // is necessary for serial connections created in one window to be usable
  27   // after that window is closed. This is necessary because the Mojo async
  28   // waiter only functions while the v8 context remains.
  29   return utils.promise(chrome.runtime.getBackgroundPage).then(function(bgPage) {
  30     return context.GetModuleSystem(bgPage).requireAsync('serial_service');
  31   }).catch(function() {
  32     return requireAsync('serial_service');
  33   });
  34 }();
  35
  36 function forwardToConnection(methodName) {
  37   return function(connectionId) {
  38     var args = $Array.slice(arguments, 1);
  39     return serialServicePromise.then(function(serialService) {
  40       return serialService.getConnection(connectionId);
  41     }).then(function(connection) {
  42       return $Function.apply(connection[methodName], connection, args);
  43     });
  44   };
  45 }
  46
  47 binding.registerCustomHook(function(bindingsAPI) {
  48   var apiFunctions = bindingsAPI.apiFunctions;
  49   apiFunctions.setHandleRequestWithPromise('getDevices', function() {
  50     return serialServicePromise.then(function(serialService) {
  51       return serialService.getDevices();
  52     });
  53   });
  54
  55   apiFunctions.setHandleRequestWithPromise('connect', function(path, options) {
  56     return serialServicePromise.then(function(serialService) {
  57       return serialService.createConnection(path, options);
  58     }).then(function(result) {
  59       var id = result.info.connectionId;
  60       result.connection.onData = function(data) {
  61         eventBindings.dispatchEvent(
  62             'serial.onReceive', [{connectionId: id, data: data}]);
  63       };
  64       result.connection.onError = function(error) {
  65         eventBindings.dispatchEvent(
  66             'serial.onReceiveError', [{connectionId: id, error: error}]);
  67       };
  68       return result.info;
  69     }).catch (function(e) {
  70       throw new Error('Failed to connect to the port.');
  71     });
  72   });
  73
  74   apiFunctions.setHandleRequestWithPromise(
  75       'disconnect', forwardToConnection('close'));
  76   apiFunctions.setHandleRequestWithPromise(
  77       'getInfo', forwardToConnection('getInfo'));
  78   apiFunctions.setHandleRequestWithPromise(
  79       'update', forwardToConnection('setOptions'));
  80   apiFunctions.setHandleRequestWithPromise(
  81       'getControlSignals', forwardToConnection('getControlSignals'));
  82   apiFunctions.setHandleRequestWithPromise(
  83       'setControlSignals', forwardToConnection('setControlSignals'));
  84   apiFunctions.setHandleRequestWithPromise(
  85       'flush', forwardToConnection('flush'));
  86   apiFunctions.setHandleRequestWithPromise(
  87       'setPaused', forwardToConnection('setPaused'));
  88   apiFunctions.setHandleRequestWithPromise(
  89       'send', forwardToConnection('send'));
  90
  91   apiFunctions.setHandleRequestWithPromise('getConnections', function() {
  92     return serialServicePromise.then(function(serialService) {
  93       return serialService.getConnections();
  94     }).then(function(connections) {
  95       var promises = [];
  96       for (var connection of connections.values()) {
  97         promises.push(connection.getInfo());
  98       }
  99       return Promise.all(promises);
 100     });
 101   });
 102 });
 103
 104 exports.binding = binding.generate();