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 utils = require('utils');
  17
  18 var serialServicePromise = function() {
  19   // getBackgroundPage is not available in unit tests so fall back to the
  20   // current page's serial_service module.
  21   if (!chrome.runtime.getBackgroundPage)
  22     return requireAsync('serial_service');
  23
  24   // Load the serial_service module from the background page if one exists. This
  25   // is necessary for serial connections created in one window to be usable
  26   // after that window is closed. This is necessary because the Mojo async
  27   // waiter only functions while the v8 context remains.
  28   return utils.promise(chrome.runtime.getBackgroundPage).then(function(bgPage) {
  29     return context.GetModuleSystem(bgPage).requireAsync('serial_service');
  30   }).catch(function() {
  31     return requireAsync('serial_service');
  32   });
  33 }();
  34
  35 function forwardToConnection(methodName) {
  36   return function(connectionId) {
  37     var args = $Array.slice(arguments, 1);
  38     return serialServicePromise.then(function(serialService) {
  39       return serialService.getConnection(connectionId);
  40     }).then(function(connection) {
  41       return $Function.apply(connection[methodName], connection, args);
  42     });
  43   };
  44 }
  45
  46 binding.registerCustomHook(function(bindingsAPI) {
  47   var apiFunctions = bindingsAPI.apiFunctions;
  48   apiFunctions.setHandleRequestWithPromise('getDevices', function() {
  49     return serialServicePromise.then(function(serialService) {
  50       return serialService.getDevices();
  51     })
  52   });
  53
  54   apiFunctions.setHandleRequestWithPromise('connect', function(path, options) {
  55     return serialServicePromise.then(function(serialService) {
  56       return serialService.createConnection(path, options);
  57     }).then(function(result) {
  58       return result.info;
  59     }).catch (function(e) {
  60       throw new Error('Failed to connect to the port.');
  61     });
  62   });
  63
  64   apiFunctions.setHandleRequestWithPromise(
  65       'disconnect', forwardToConnection('close'));
  66   apiFunctions.setHandleRequestWithPromise(
  67       'getInfo', forwardToConnection('getInfo'));
  68   apiFunctions.setHandleRequestWithPromise(
  69       'update', forwardToConnection('setOptions'));
  70   apiFunctions.setHandleRequestWithPromise(
  71       'getControlSignals', forwardToConnection('getControlSignals'));
  72   apiFunctions.setHandleRequestWithPromise(
  73       'setControlSignals', forwardToConnection('setControlSignals'));
  74   apiFunctions.setHandleRequestWithPromise(
  75       'flush', forwardToConnection('flush'));
  76   apiFunctions.setHandleRequestWithPromise(
  77       'setPaused', forwardToConnection('setPaused'));
  78
  79   apiFunctions.setHandleRequestWithPromise('getConnections', function() {
  80     return serialServicePromise.then(function(serialService) {
  81       return serialService.getConnections();
  82     }).then(function(connections) {
  83       var promises = [];
  84       for (var id in connections) {
  85         promises.push(connections[id].getInfo());
  86       }
  87       return Promise.all(promises);
  88     });
  89   });
  90 });
  91
  92 exports.binding = binding.generate();