Dart: Wait to handle events on a Stub until it makes sense to do it.

mojo/dart/packages/mojo_services/lib/http_server/http_server.mojom.dart

 // 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.
 
 library http_server_mojom;
 import 'dart:async';
 import 'package:mojo/bindings.dart' as bindings;
 import 'package:mojo/core.dart' as core;
 import 'package:mojo/mojo/bindings/types/service_describer.mojom.dart' as service_describer;
 import 'package:mojo_services/http_server/http_request.mojom.dart' as http_request_mojom;
@@ skipping 603 matching lines @@
     impl.requireVersion(requiredVersion);
   }
 
   String toString() {
     return "HttpServerProxy($impl)";
   }
 }
 
 
 class HttpServerStub extends bindings.Stub {
-  HttpServer _impl = null;
+  HttpServer _impl;
 
   HttpServerStub.fromEndpoint(
-      core.MojoMessagePipeEndpoint endpoint, [this._impl])
-      : super.fromEndpoint(endpoint);
+      core.MojoMessagePipeEndpoint endpoint, [HttpServer impl])
+      : super.fromEndpoint(endpoint, autoBegin: impl != null) {
+    _impl = impl;
+  }
 
-  HttpServerStub.fromHandle(core.MojoHandle handle, [this._impl])
-      : super.fromHandle(handle);
+  HttpServerStub.fromHandle(
+      core.MojoHandle handle, [HttpServer impl])
+      : super.fromHandle(handle, autoBegin: impl != null) {
+    _impl = impl;
+  }
 
   HttpServerStub.unbound() : super.unbound();
 
   static HttpServerStub newFromEndpoint(
       core.MojoMessagePipeEndpoint endpoint) {
     assert(endpoint.setDescription("For HttpServerStub"));
     return new HttpServerStub.fromEndpoint(endpoint);
   }
 
 
   HttpServerSetHandlerResponseParams _httpServerSetHandlerResponseParamsFactory(bool success) {
     var result = new HttpServerSetHandlerResponseParams();
     result.success = success;
     return result;
   }
   HttpServerGetPortResponseParams _httpServerGetPortResponseParamsFactory(int port) {
     var result = new HttpServerGetPortResponseParams();
     result.port = port;
     return result;
   }
 
   dynamic handleMessage(bindings.ServiceMessage message) {
     if (bindings.ControlMessageHandler.isControlMessage(message)) {
       return bindings.ControlMessageHandler.handleMessage(this,
                                                           0,
                                                           message);
     }
-    assert(_impl != null);
+    if (_impl == null) {
+      throw new core.MojoApiError("$this has no implementation set");
+    }
     switch (message.header.type) {
       case _httpServerMethodSetHandlerName:
         var params = _HttpServerSetHandlerParams.deserialize(
             message.payload);
         var response = _impl.setHandler(params.pattern,params.handler,_httpServerSetHandlerResponseParamsFactory);
         if (response is Future) {
           return response.then((response) {
             if (response != null) {
               return buildResponseWithId(
                   response,
@@ skipping 32 matching lines @@
         break;
       default:
         throw new bindings.MojoCodecError("Unexpected message name");
         break;
     }
     return null;
   }
 
   HttpServer get impl => _impl;
   set impl(HttpServer d) {
-    assert(_impl == null);
+    if (d == null) {
+      throw new core.MojoApiError("$this: Cannot set a null implementation");
+    }
+    if (isBound && (_impl == null)) {
+      beginHandlingEvents();
+    }
     _impl = d;
   }
 
+  @override
+  void bind(core.MojoMessagePipeEndpoint endpoint) {
+    super.bind(endpoint);
+    if (!isOpen && (_impl != null)) {
+      beginHandlingEvents();
+    }
+  }
+
   String toString() {
     var superString = super.toString();
     return "HttpServerStub($superString)";
   }
 
   int get version => 0;
 
   static service_describer.ServiceDescription _cachedServiceDescription;
   static service_describer.ServiceDescription get serviceDescription {
     if (_cachedServiceDescription == null) {
@@ skipping 145 matching lines @@
     impl.requireVersion(requiredVersion);
   }
 
   String toString() {
     return "HttpHandlerProxy($impl)";
   }
 }
 
 
 class HttpHandlerStub extends bindings.Stub {
-  HttpHandler _impl = null;
+  HttpHandler _impl;
 
   HttpHandlerStub.fromEndpoint(
-      core.MojoMessagePipeEndpoint endpoint, [this._impl])
-      : super.fromEndpoint(endpoint);
+      core.MojoMessagePipeEndpoint endpoint, [HttpHandler impl])
+      : super.fromEndpoint(endpoint, autoBegin: impl != null) {
+    _impl = impl;
+  }
 
-  HttpHandlerStub.fromHandle(core.MojoHandle handle, [this._impl])
-      : super.fromHandle(handle);
+  HttpHandlerStub.fromHandle(
+      core.MojoHandle handle, [HttpHandler impl])
+      : super.fromHandle(handle, autoBegin: impl != null) {
+    _impl = impl;
+  }
 
   HttpHandlerStub.unbound() : super.unbound();
 
   static HttpHandlerStub newFromEndpoint(
       core.MojoMessagePipeEndpoint endpoint) {
     assert(endpoint.setDescription("For HttpHandlerStub"));
     return new HttpHandlerStub.fromEndpoint(endpoint);
   }
 
 
   HttpHandlerHandleRequestResponseParams _httpHandlerHandleRequestResponseParamsFactory(http_response_mojom.HttpResponse response) {
     var result = new HttpHandlerHandleRequestResponseParams();
     result.response = response;
     return result;
   }
 
   dynamic handleMessage(bindings.ServiceMessage message) {
     if (bindings.ControlMessageHandler.isControlMessage(message)) {
       return bindings.ControlMessageHandler.handleMessage(this,
                                                           0,
                                                           message);
     }
-    assert(_impl != null);
+    if (_impl == null) {
+      throw new core.MojoApiError("$this has no implementation set");
+    }
     switch (message.header.type) {
       case _httpHandlerMethodHandleRequestName:
         var params = _HttpHandlerHandleRequestParams.deserialize(
             message.payload);
         var response = _impl.handleRequest(params.request,_httpHandlerHandleRequestResponseParamsFactory);
         if (response is Future) {
           return response.then((response) {
             if (response != null) {
               return buildResponseWithId(
                   response,
@@ skipping 12 matching lines @@
         break;
       default:
         throw new bindings.MojoCodecError("Unexpected message name");
         break;
     }
     return null;
   }
 
   HttpHandler get impl => _impl;
   set impl(HttpHandler d) {
-    assert(_impl == null);
+    if (d == null) {
+      throw new core.MojoApiError("$this: Cannot set a null implementation");
+    }
+    if (isBound && (_impl == null)) {
+      beginHandlingEvents();
+    }
     _impl = d;
   }
 
+  @override
+  void bind(core.MojoMessagePipeEndpoint endpoint) {
+    super.bind(endpoint);
+    if (!isOpen && (_impl != null)) {
+      beginHandlingEvents();
+    }
+  }
+
   String toString() {
     var superString = super.toString();
     return "HttpHandlerStub($superString)";
   }
 
   int get version => 0;
 
   static service_describer.ServiceDescription _cachedServiceDescription;
   static service_describer.ServiceDescription get serviceDescription {
     if (_cachedServiceDescription == null) {
       _cachedServiceDescription = new _HttpHandlerServiceDescription();
     }
     return _cachedServiceDescription;
   }
 }