third_party/mojo_services/src/public/js/service_exchange.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/services/public/js/service_exchange", [
   6   "mojo/public/js/bindings",
   7   "mojo/public/interfaces/application/service_provider.mojom",
   8   "mojo/public/js/connection",
   9 ], function(bindings, spMojom, connection) {
  10
  11   const ProxyBindings = bindings.ProxyBindings;
  12   const StubBindings = bindings.StubBindings;
  13   const ServiceProviderInterface = spMojom.ServiceProvider;
  14
  15   function checkServiceExchange(exch) {
  16     if (!exch.providers_)
  17       throw new Error("Service was closed");
  18   }
  19
  20   class ServiceExchange {
  21     constructor(servicesRequest, exposedServicesProxy) {
  22       this.proxy = exposedServicesProxy;
  23       this.providers_ = new Map(); // serviceName => see provideService() below
  24       this.pendingRequests_ = new Map(); // serviceName => serviceHandle
  25       if (servicesRequest)
  26         StubBindings(servicesRequest).delegate = this;
  27     }
  28
  29     // Incoming requests
  30     connectToService(serviceName, serviceHandle) {
  31       if (!this.providers_) // We're closed.
  32         return;
  33
  34       var provider = this.providers_.get(serviceName);
  35       if (!provider) {
  36         this.pendingRequests_.set(serviceName, serviceHandle);
  37         return;
  38       }
  39
  40       var stub = connection.bindHandleToStub(serviceHandle, provider.service);
  41       StubBindings(stub).delegate = new provider.factory();
  42       provider.connections.push(StubBindings(stub).connection);
  43     }
  44
  45     provideService(service, factory) {
  46       checkServiceExchange(this);
  47
  48       var provider = {
  49         service: service, // A JS bindings interface object.
  50         factory: factory, // factory() => interface implemntation
  51         connections: [],
  52       };
  53       this.providers_.set(service.name, provider);
  54
  55       if (this.pendingRequests_.has(service.name)) {
  56         this.connectToService(service.name, pendingRequests_.get(service.name));
  57         pendingRequests_.delete(service.name);
  58       }
  59       return this;
  60     }
  61
  62     // Outgoing requests
  63     requestService(interfaceObject) {
  64       checkServiceExchange(this);
  65       if (!interfaceObject.name)
  66         throw new Error("Invalid service parameter");
  67
  68       var serviceProxy;
  69       var serviceHandle = connection.bindProxy(
  70           function(sp) {serviceProxy = sp;}, interfaceObject);
  71       this.proxy.connectToService(interfaceObject.name, serviceHandle);
  72       return serviceProxy;
  73     };
  74
  75     close() {
  76       this.providers_ = null;
  77       this.pendingRequests_ = null;
  78     }
  79   }
  80
  81   var exports = {};
  82   exports.ServiceExchange = ServiceExchange;
  83   return exports;
  84 });