src/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   "mojo/public/js/bindings/validator",
   9 ], function(codec, connector, validator) {
  10
  11   function Router(handle, connectorFactory) {
  12     if (connectorFactory === undefined)
  13       connectorFactory = connector.Connector;
  14     this.connector_ = new connectorFactory(handle);
  15     this.incomingReceiver_ = null;
  16     this.nextRequestID_ = 0;
  17     this.responders_ = {};
  18     this.payloadValidators_ = [];
  19
  20     this.connector_.setIncomingReceiver({
  21         accept: this.handleIncomingMessage_.bind(this),
  22     });
  23     this.connector_.setErrorHandler({
  24         onError: this.handleConnectionError_.bind(this),
  25     });
  26   }
  27
  28   Router.prototype.close = function() {
  29     this.responders_ = {};  // Drop any responders.
  30     this.connector_.close();
  31   };
  32
  33   Router.prototype.accept = function(message) {
  34     this.connector_.accept(message);
  35   };
  36
  37   Router.prototype.reject = function(message) {
  38     // TODO(mpcomplete): no way to trasmit errors over a Connection.
  39   };
  40
  41   Router.prototype.acceptWithResponder = function(message, responder) {
  42     // Reserve 0 in case we want it to convey special meaning in the future.
  43     var requestID = this.nextRequestID_++;
  44     if (requestID == 0)
  45       requestID = this.nextRequestID_++;
  46
  47     message.setRequestID(requestID);
  48     var result = this.connector_.accept(message);
  49
  50     this.responders_[requestID] = responder;
  51
  52     // TODO(mpcomplete): accept should return a Promise too, maybe?
  53     if (result)
  54       return Promise.resolve();
  55     return Promise.reject(Error("Connection error"));
  56   };
  57
  58   Router.prototype.setIncomingReceiver = function(receiver) {
  59     this.incomingReceiver_ = receiver;
  60   };
  61
  62   Router.prototype.setPayloadValidators = function(payloadValidators) {
  63     this.payloadValidators_ = payloadValidators;
  64   };
  65
  66   Router.prototype.encounteredError = function() {
  67     return this.connector_.encounteredError();
  68   };
  69
  70   Router.prototype.handleIncomingMessage_ = function(message) {
  71     var noError = validator.validationError.NONE;
  72     var messageValidator = new validator.Validator(message);
  73     var err = messageValidator.validateMessageHeader();
  74     for (var i = 0; err === noError && i < this.payloadValidators_.length; ++i)
  75       err = this.payloadValidators_[i](messageValidator);
  76
  77     if (err == noError)
  78       this.handleValidIncomingMessage_(message);
  79     else
  80       this.handleInvalidIncomingMessage_(message, err);
  81   };
  82
  83   Router.prototype.handleValidIncomingMessage_ = function(message) {
  84     if (message.expectsResponse()) {
  85       if (this.incomingReceiver_) {
  86         this.incomingReceiver_.acceptWithResponder(message, this);
  87       } else {
  88         // If we receive a request expecting a response when the client is not
  89         // listening, then we have no choice but to tear down the pipe.
  90         this.close();
  91       }
  92     } else if (message.isResponse()) {
  93       var reader = new codec.MessageReader(message);
  94       var requestID = reader.requestID;
  95       var responder = this.responders_[requestID];
  96       delete this.responders_[requestID];
  97       responder.accept(message);
  98     } else {
  99       if (this.incomingReceiver_)
 100         this.incomingReceiver_.accept(message);
 101     }
 102   }
 103
 104   Router.prototype.handleInvalidIncomingMessage_ = function(message, error) {
 105     this.close();
 106   }
 107
 108   Router.prototype.handleConnectionError_ = function(result) {
 109     for (var each in this.responders_)
 110       this.responders_[each].reject(result);
 111     this.close();
 112   };
 113
 114   // The TestRouter subclass is only intended to be used in unit tests.
 115   // It defeats valid message handling and delgates invalid message handling.
 116
 117   function TestRouter(handle, connectorFactory) {
 118     Router.call(this, handle, connectorFactory);
 119   }
 120
 121   TestRouter.prototype = Object.create(Router.prototype);
 122
 123   TestRouter.prototype.handleValidIncomingMessage_ = function() {
 124   };
 125
 126   TestRouter.prototype.handleInvalidIncomingMessage_ =
 127       function(message, error) {
 128         this.validationErrorHandler(error);
 129       };
 130
 131   var exports = {};
 132   exports.Router = Router;
 133   exports.TestRouter = TestRouter;
 134   return exports;
 135 });