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 function addEventListeners(connection, id) {
  48   connection.onData = function(data) {
  49     eventBindings.dispatchEvent(
  50         'serial.onReceive', [{connectionId: id, data: data}]);
  51   };
  52   connection.onError = function(error) {
  53     eventBindings.dispatchEvent(
  54         'serial.onReceiveError', [{connectionId: id, error: error}]);
  55   };
  56 }
  57
  58 serialServicePromise.then(function(serialService) {
  59   return serialService.getConnections().then(function(connections) {
  60     for (var entry of connections) {
  61       var connection = entry[1];
  62       addEventListeners(connection, entry[0]);
  63       connection.resumeReceives();
  64     };
  65   });
  66 });
  67
  68 binding.registerCustomHook(function(bindingsAPI) {
  69   var apiFunctions = bindingsAPI.apiFunctions;
  70   apiFunctions.setHandleRequestWithPromise('getDevices', function() {
  71     return serialServicePromise.then(function(serialService) {
  72       return serialService.getDevices();
  73     });
  74   });
  75
  76   apiFunctions.setHandleRequestWithPromise('connect', function(path, options) {
  77     return serialServicePromise.then(function(serialService) {
  78       return serialService.createConnection(path, options);
  79     }).then(function(result) {
  80       addEventListeners(result.connection, result.info.connectionId);
  81       return result.info;
  82     }).catch (function(e) {
  83       throw new Error('Failed to connect to the port.');
  84     });
  85   });
  86
  87   apiFunctions.setHandleRequestWithPromise(
  88       'disconnect', forwardToConnection('close'));
  89   apiFunctions.setHandleRequestWithPromise(
  90       'getInfo', forwardToConnection('getInfo'));
  91   apiFunctions.setHandleRequestWithPromise(
  92       'update', forwardToConnection('setOptions'));
  93   apiFunctions.setHandleRequestWithPromise(
  94       'getControlSignals', forwardToConnection('getControlSignals'));
  95   apiFunctions.setHandleRequestWithPromise(
  96       'setControlSignals', forwardToConnection('setControlSignals'));
  97   apiFunctions.setHandleRequestWithPromise(
  98       'flush', forwardToConnection('flush'));
  99   apiFunctions.setHandleRequestWithPromise(
 100       'setPaused', forwardToConnection('setPaused'));
 101   apiFunctions.setHandleRequestWithPromise(
 102       'send', forwardToConnection('send'));
 103
 104   apiFunctions.setHandleRequestWithPromise('getConnections', function() {
 105     return serialServicePromise.then(function(serialService) {
 106       return serialService.getConnections();
 107     }).then(function(connections) {
 108       var promises = [];
 109       for (var connection of connections.values()) {
 110         promises.push(connection.getInfo());
 111       }
 112       return Promise.all(promises);
 113     });
 114   });
 115 });
 116
 117 exports.binding = binding.generate();