mojo/public/js/bindings/router.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 define("mojo/public/js/bindings/router", [
   6   "mojo/public/js/bindings/codec",
   7   "mojo/public/js/bindings/connector",
   8 ], function(codec, connector) {
   9
  10   function Router(handle) {
  11     this.connector_ = new connector.Connector(handle);
  12     this.incomingReceiver_ = null;
  13     this.nextRequestID_ = 0;
  14     this.responders_ = {};
  15
  16     this.connector_.setIncomingReceiver({
  17         accept: this.handleIncomingMessage_.bind(this),
  18     });
  19     this.connector_.setErrorHandler({
  20         onError: this.handleConnectionError_.bind(this),
  21     });
  22   }
  23
  24   Router.prototype.close = function() {
  25     this.responders_ = {};  // Drop any responders.
  26     this.connector_.close();
  27   };
  28
  29   Router.prototype.accept = function(message) {
  30     this.connector_.accept(message);
  31   };
  32
  33   Router.prototype.reject = function(message) {
  34     // TODO(mpcomplete): no way to trasmit errors over a Connection.
  35   };
  36
  37   Router.prototype.acceptWithResponder = function(message, responder) {
  38     // Reserve 0 in case we want it to convey special meaning in the future.
  39     var requestID = this.nextRequestID_++;
  40     if (requestID == 0)
  41       requestID = this.nextRequestID_++;
  42
  43     message.setRequestID(requestID);
  44     var result = this.connector_.accept(message);
  45
  46     this.responders_[requestID] = responder;
  47
  48     // TODO(mpcomplete): accept should return a Promise too, maybe?
  49     if (result)
  50       return Promise.resolve();
  51     return Promise.reject(Error("Connection error"));
  52   };
  53
  54   Router.prototype.setIncomingReceiver = function(receiver) {
  55     this.incomingReceiver_ = receiver;
  56   };
  57
  58   Router.prototype.encounteredError = function() {
  59     return this.connector_.encounteredError();
  60   };
  61
  62   Router.prototype.handleIncomingMessage_ = function(message) {
  63     var flags = message.getFlags();
  64     if (flags & codec.kMessageExpectsResponse) {
  65       if (this.incomingReceiver_) {
  66         this.incomingReceiver_.acceptWithResponder(message, this);
  67       } else {
  68         // If we receive a request expecting a response when the client is not
  69         // listening, then we have no choice but to tear down the pipe.
  70         this.close();
  71       }
  72     } else if (flags & codec.kMessageIsResponse) {
  73       var reader = new codec.MessageReader(message);
  74       var requestID = reader.requestID;
  75       var responder = this.responders_[requestID];
  76       delete this.responders_[requestID];
  77       responder.accept(message);
  78     } else {
  79       if (this.incomingReceiver_)
  80         this.incomingReceiver_.accept(message);
  81     }
  82   };
  83
  84   Router.prototype.handleConnectionError_ = function(result) {
  85     for (var each in this.responders_)
  86       this.responders_[each].reject(result);
  87     this.close();
  88   };
  89
  90   var exports = {};
  91   exports.Router = Router;
  92   return exports;
  93 });