Dart: Refactor Stubs

mojo/dart/packages/mojo/lib/src/stub.dart

Index: mojo/dart/packages/mojo/lib/src/stub.dart
diff --git a/mojo/dart/packages/mojo/lib/src/stub.dart b/mojo/dart/packages/mojo/lib/src/stub.dart
index 2b95ea777ee2a5af60721d3833e2a60658e2b77f..a076533667d15204959653b14a2e9a07b44010f3 100644
--- a/mojo/dart/packages/mojo/lib/src/stub.dart
+++ b/mojo/dart/packages/mojo/lib/src/stub.dart
@@ -4,22 +4,61 @@
 
 part of bindings;
 
-abstract class Stub extends core.MojoEventHandler {
+/// Generated StubControl classes implement this interface.
+/// StubControl objects are accessible through the [ctrl] field on Stubs.
+abstract class StubControl<T> implements StubMessageHandler {
+  T impl;
+}
+
+/// Generated Stub classes extend this base class.
+class Stub<T> {
+  // In general it's probalby better to avoid adding fields and methods to this
+  // class. Names added to this class have to be mangled by Mojo bindings
+  // generation to avoid name conflicts.
+
+  /// Proxies control the StubMessageHandler by way of this [StubControl]
+  /// object.
+  final StubControl<T> ctrl;
+
+  Stub(this.ctrl);
+
+  /// This is a convenience method that simply forwards to ctrl.close().
+  /// If a Mojo interface has a method 'close', its name will be mangled to be
+  /// 'close_'.
+  Future close({bool immediate: false}) => ctrl.close(immediate: immediate);
+
+  /// This getter and setter pair is for convenience and simply forwards to
+  /// ctrl.impl. If a Mojo interface has a method 'close', its name will be
+  /// mangled to be 'impl_'.
+  T get impl => ctrl.impl;
+  set impl(T impl) {
+    ctrl.impl = impl;
+  }
+}
+
+abstract class StubMessageHandler extends core.MojoEventHandler {
   int _outstandingResponseFutures = 0;
   bool _isClosing = false;
   Completer _closeCompleter;
 
-  Stub.fromEndpoint(core.MojoMessagePipeEndpoint endpoint,
-                    {bool autoBegin: true})
+  StubMessageHandler.fromEndpoint(core.MojoMessagePipeEndpoint endpoint,
+                                  {bool autoBegin: true})
       : super.fromEndpoint(endpoint, autoBegin: autoBegin);
 
-  Stub.fromHandle(core.MojoHandle handle, {bool autoBegin: true})
+  StubMessageHandler.fromHandle(core.MojoHandle handle, {bool autoBegin: true})
       : super.fromHandle(handle, autoBegin: autoBegin);
 
-  Stub.unbound() : super.unbound();
+  StubMessageHandler.unbound() : super.unbound();
 
+  /// Generated StubControl classes implement this method to route messages to
+  /// the correct implementation method.
   dynamic handleMessage(ServiceMessage message);
 
+  /// Generated StubControl classes implement this getter to return the version
+  /// of the mojom interface for which the bindings are generated.
+  int get version;
+
+  @override
   void handleRead() {
     var result = endpoint.queryAndRead();
     if ((result.data == null) || (result.dataLength == 0)) {
@@ -64,29 +103,7 @@ abstract class Stub extends core.MojoEventHandler {
     }
   }
 
-  void _sendResponse(Message response) {
-    if (isOpen) {
-      endpoint.write(
-          response.buffer, response.buffer.lengthInBytes, response.handles);
-      // FailedPrecondition is only used to indicate that the other end of
-      // the pipe has been closed. We can ignore the close here and wait for
-      // the PeerClosed signal on the event stream.
-      assert((endpoint.status == core.MojoResult.kOk) ||
-          (endpoint.status == core.MojoResult.kFailedPrecondition));
-      if (_isClosing && (_outstandingResponseFutures == 0)) {
-        // This was the final response future for which we needed to send
-        // a response. It is safe to close.
-        super.close().then((_) {
-          if (_isClosing) {
-            _isClosing = false;
-            _closeCompleter.complete(null);
-            _closeCompleter = null;
-          }
-        });
-      }
-    }
-  }
-
+  @override
   void handleWrite() {
     throw 'Unexpected write signal in client.';
   }
@@ -128,15 +145,37 @@ abstract class Stub extends core.MojoEventHandler {
     return response.serializeWithHeader(header);
   }
 
+  @override
   String toString() {
     var superString = super.toString();
-    return "Stub(${superString})";
+    return "StubMessageHandler(${superString})";
   }
 
-  int get version;
-
   /// Returns a service description, which exposes the mojom type information
   /// of the service being stubbed.
   /// Note: The description is null or incomplete if type info is unavailable.
   service_describer.ServiceDescription get description => null;
+
+  void _sendResponse(Message response) {
+    if (isOpen) {
+      endpoint.write(
+          response.buffer, response.buffer.lengthInBytes, response.handles);
+      // FailedPrecondition is only used to indicate that the other end of
+      // the pipe has been closed. We can ignore the close here and wait for
+      // the PeerClosed signal on the event stream.
+      assert((endpoint.status == core.MojoResult.kOk) ||
+          (endpoint.status == core.MojoResult.kFailedPrecondition));
+      if (_isClosing && (_outstandingResponseFutures == 0)) {
+        // This was the final response future for which we needed to send
+        // a response. It is safe to close.
+        super.close().then((_) {
+          if (_isClosing) {
+            _isClosing = false;
+            _closeCompleter.complete(null);
+            _closeCompleter = null;
+          }
+        });
+      }
+    }
+  }
 }