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

mojo/dart/packages/mojo_services/lib/activity/activity.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 activity_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;
 
@@ skipping 1826 matching lines @@
     impl.requireVersion(requiredVersion);
   }
 
   String toString() {
     return "ActivityProxy($impl)";
   }
 }
 
 
 class ActivityStub extends bindings.Stub {
-  Activity _impl = null;
+  Activity _impl;
 
   ActivityStub.fromEndpoint(
-      core.MojoMessagePipeEndpoint endpoint, [this._impl])
-      : super.fromEndpoint(endpoint);
+      core.MojoMessagePipeEndpoint endpoint, [Activity impl])
+      : super.fromEndpoint(endpoint, autoBegin: impl != null) {
+    _impl = impl;
+  }
 
-  ActivityStub.fromHandle(core.MojoHandle handle, [this._impl])
-      : super.fromHandle(handle);
+  ActivityStub.fromHandle(
+      core.MojoHandle handle, [Activity impl])
+      : super.fromHandle(handle, autoBegin: impl != null) {
+    _impl = impl;
+  }
 
   ActivityStub.unbound() : super.unbound();
 
   static ActivityStub newFromEndpoint(
       core.MojoMessagePipeEndpoint endpoint) {
     assert(endpoint.setDescription("For ActivityStub"));
     return new ActivityStub.fromEndpoint(endpoint);
   }
 
 
 
   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 _activityMethodGetUserFeedbackName:
         var params = _ActivityGetUserFeedbackParams.deserialize(
             message.payload);
         _impl.getUserFeedback(params.userFeedback);
         break;
       case _activityMethodStartActivityName:
         var params = _ActivityStartActivityParams.deserialize(
             message.payload);
         _impl.startActivity(params.intent);
@@ skipping 18 matching lines @@
         break;
       default:
         throw new bindings.MojoCodecError("Unexpected message name");
         break;
     }
     return null;
   }
 
   Activity get impl => _impl;
   set impl(Activity 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 "ActivityStub($superString)";
   }
 
   int get version => 0;
 
   static service_describer.ServiceDescription _cachedServiceDescription;
   static service_describer.ServiceDescription get serviceDescription {
     if (_cachedServiceDescription == null) {
@@ skipping 204 matching lines @@
     impl.requireVersion(requiredVersion);
   }
 
   String toString() {
     return "PathServiceProxy($impl)";
   }
 }
 
 
 class PathServiceStub extends bindings.Stub {
-  PathService _impl = null;
+  PathService _impl;
 
   PathServiceStub.fromEndpoint(
-      core.MojoMessagePipeEndpoint endpoint, [this._impl])
-      : super.fromEndpoint(endpoint);
+      core.MojoMessagePipeEndpoint endpoint, [PathService impl])
+      : super.fromEndpoint(endpoint, autoBegin: impl != null) {
+    _impl = impl;
+  }
 
-  PathServiceStub.fromHandle(core.MojoHandle handle, [this._impl])
-      : super.fromHandle(handle);
+  PathServiceStub.fromHandle(
+      core.MojoHandle handle, [PathService impl])
+      : super.fromHandle(handle, autoBegin: impl != null) {
+    _impl = impl;
+  }
 
   PathServiceStub.unbound() : super.unbound();
 
   static PathServiceStub newFromEndpoint(
       core.MojoMessagePipeEndpoint endpoint) {
     assert(endpoint.setDescription("For PathServiceStub"));
     return new PathServiceStub.fromEndpoint(endpoint);
   }
 
 
@@ skipping 12 matching lines @@
     result.path = path;
     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 _pathServiceMethodGetAppDataDirName:
         var response = _impl.getAppDataDir(_pathServiceGetAppDataDirResponseParamsFactory);
         if (response is Future) {
           return response.then((response) {
             if (response != null) {
               return buildResponseWithId(
                   response,
                   _pathServiceMethodGetAppDataDirName,
                   message.header.requestId,
@@ skipping 50 matching lines @@
         break;
       default:
         throw new bindings.MojoCodecError("Unexpected message name");
         break;
     }
     return null;
   }
 
   PathService get impl => _impl;
   set impl(PathService 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 "PathServiceStub($superString)";
   }
 
   int get version => 0;
 
   static service_describer.ServiceDescription _cachedServiceDescription;
   static service_describer.ServiceDescription get serviceDescription {
     if (_cachedServiceDescription == null) {
@@ skipping 136 matching lines @@
     impl.requireVersion(requiredVersion);
   }
 
   String toString() {
     return "UserFeedbackProxy($impl)";
   }
 }
 
 
 class UserFeedbackStub extends bindings.Stub {
-  UserFeedback _impl = null;
+  UserFeedback _impl;
 
   UserFeedbackStub.fromEndpoint(
-      core.MojoMessagePipeEndpoint endpoint, [this._impl])
-      : super.fromEndpoint(endpoint);
+      core.MojoMessagePipeEndpoint endpoint, [UserFeedback impl])
+      : super.fromEndpoint(endpoint, autoBegin: impl != null) {
+    _impl = impl;
+  }
 
-  UserFeedbackStub.fromHandle(core.MojoHandle handle, [this._impl])
-      : super.fromHandle(handle);
+  UserFeedbackStub.fromHandle(
+      core.MojoHandle handle, [UserFeedback impl])
+      : super.fromHandle(handle, autoBegin: impl != null) {
+    _impl = impl;
+  }
 
   UserFeedbackStub.unbound() : super.unbound();
 
   static UserFeedbackStub newFromEndpoint(
       core.MojoMessagePipeEndpoint endpoint) {
     assert(endpoint.setDescription("For UserFeedbackStub"));
     return new UserFeedbackStub.fromEndpoint(endpoint);
   }
 
 
 
   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 _userFeedbackMethodPerformHapticFeedbackName:
         var params = _UserFeedbackPerformHapticFeedbackParams.deserialize(
             message.payload);
         _impl.performHapticFeedback(params.type);
         break;
       case _userFeedbackMethodPerformAuralFeedbackName:
         var params = _UserFeedbackPerformAuralFeedbackParams.deserialize(
             message.payload);
         _impl.performAuralFeedback(params.type);
         break;
       default:
         throw new bindings.MojoCodecError("Unexpected message name");
         break;
     }
     return null;
   }
 
   UserFeedback get impl => _impl;
   set impl(UserFeedback 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 "UserFeedbackStub($superString)";
   }
 
   int get version => 0;
 
   static service_describer.ServiceDescription _cachedServiceDescription;
   static service_describer.ServiceDescription get serviceDescription {
     if (_cachedServiceDescription == null) {
       _cachedServiceDescription = new _UserFeedbackServiceDescription();
     }
     return _cachedServiceDescription;
   }
 }