mojo/public/js/connection.js

// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

define("mojo/public/js/connection", [
  "mojo/public/js/connector",
  "mojo/public/js/core",
  "mojo/public/js/router",
], function(connector, core, router) {

  var Router = router.Router;
  var TestConnector = connector.TestConnector;
  var TestRouter = router.TestRouter;

  // TODO(hansmuller): the proxy receiver_ property should be receiver$

  function BaseConnection(localStub, remoteProxy, router) {
    this.router_ = router;
    this.local = localStub;
    this.remote = remoteProxy;

    this.router_.setIncomingReceiver(localStub);
    if (this.remote)
      this.remote.receiver_ = router;

    // Validate incoming messages: remote responses and local requests.
    var validateRequest = localStub && localStub.validator;
    var validateResponse = remoteProxy && remoteProxy.validator;
    var payloadValidators = [];
    if (validateRequest)
      payloadValidators.push(validateRequest);
    if (validateResponse)
      payloadValidators.push(validateResponse);
    this.router_.setPayloadValidators(payloadValidators);
  }

  BaseConnection.prototype.close = function() {
    this.router_.close();
    this.router_ = null;
    this.local = null;
    this.remote = null;
  };

  BaseConnection.prototype.encounteredError = function() {
    return this.router_.encounteredError();
  };

  function Connection(
      handle, localFactory, remoteFactory, routerFactory, connectorFactory) {
    var routerClass = routerFactory || Router;
    var router = new routerClass(handle, connectorFactory);
    var remoteProxy = remoteFactory && new remoteFactory(router);
    var localStub = localFactory && new localFactory(remoteProxy);
    BaseConnection.call(this, localStub, remoteProxy, router);
  }

  Connection.prototype = Object.create(BaseConnection.prototype);

  // The TestConnection subclass is only intended to be used in unit tests.
  function TestConnection(handle, localFactory, remoteFactory) {
    Connection.call(this,
                    handle,
                    localFactory,
                    remoteFactory,
                    TestRouter,
                    TestConnector);
  }

  TestConnection.prototype = Object.create(Connection.prototype);

  // Called by the generated interface Proxy constructor classes.
  function initProxyInstance(proxy, proxyInterface, receiver) {
    Object.defineProperty(proxy, 'local$', {
      get: function() {
        return proxy.connection$ &&
          proxy.connection$.local && proxy.connection$.local.delegate$
      },
      set: function(value) {
        // TODO: what if the connection hasn't been created yet?
        if (proxy.connection$ && proxy.connection$.local) {
          proxy.connection$.local.delegate$ = value;
          value.remote$ = proxy;
        }
      }
    });
    // TODO(hansmuller): Temporary, for Chrome backwards compatibility.
    if (receiver instanceof Router)
      proxy.receiver_ = receiver;
  }

  function createEmptyProxy() {
    var proxy = {};
    initProxyInstance(proxy);
    return proxy;
  }

  function createOpenConnection(
      messagePipeHandle, clientImpl, localInterface, remoteInterface) {
    var stubClass = localInterface && localInterface.stubClass
    var proxyClass = remoteInterface && remoteInterface.proxyClass;
    var stub = stubClass &&
        (clientImpl ? new stubClass(clientImpl) : new stubClass);
    var proxy = proxyClass ? new proxyClass : createEmptyProxy();
    var router = new Router(messagePipeHandle);
    var connection = new BaseConnection(stub, proxy, router);
    proxy.connection$ = connection;
    if (clientImpl) {
      clientImpl.connection$ = connection;
      clientImpl.remote$ = proxy;
    }
    return connection;
  }

  // Return a message pipe handle.
  function bindProxyClient(clientImpl, localInterface, remoteInterface) {
    var messagePipe = core.createMessagePipe();
    if (messagePipe.result != core.RESULT_OK)
      throw new Error("createMessagePipe failed " + messagePipe.result);

    createOpenConnection(
      messagePipe.handle0, clientImpl, localInterface, remoteInterface);
    return messagePipe.handle1;
  }

  // Return a proxy.
  function bindProxyHandle(proxyHandle, localInterface, remoteInterface) {
    if (!core.isHandle(proxyHandle))
      throw new Error("Not a handle " + proxyHandle);

    var connection = createOpenConnection(
        proxyHandle, undefined, localInterface, remoteInterface);
    return connection.remote;
  }

  var exports = {};
  exports.Connection = Connection;
  exports.TestConnection = TestConnection;
  exports.bindProxyHandle = bindProxyHandle;
  exports.bindProxyClient = bindProxyClient;
  exports.initProxyInstance = initProxyInstance;
  return exports;
});