Implement 'print', 'up', 'down', and 'frame' commands in the Observatory debugger.

runtime/vm/service/message.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of vmservice;
 
 class Message {
   final Completer _completer = new Completer.sync();
   bool get completed => _completer.isCompleted;
   /// Future of response.
   Future<String> get response => _completer.future;
 
+  // Client-side identifier for this message.
+  final serial;
+
   // In new messages.
   final String method;
 
   // In old messages.
   final List path = new List();
 
   final Map params = new Map();
 
   void _setPath(List<String> pathSegments) {
     if (pathSegments == null) {
       return;
     }
     pathSegments.forEach((String segment) {
       if (segment == null || segment == '') {
         return;
       }
       path.add(segment);
     });
   }
 
-  Message.fromJsonRpc(this.method, Map rpcParams) {
-    params.addAll(rpcParams);
+  Message.fromJsonRpc(Map map) : serial = map['id'], method = map['method'] {
+    params.addAll(map['params']);
   }
 
   static String _methodNameFromUri(Uri uri) {
     if (uri == null) {
       return '';
     }
     if (uri.pathSegments.length == 0) {
       return '';
     }
     return uri.pathSegments[0];
@@ skipping 24 matching lines @@
       }
       list[i] = list[i].toString();
     }
     return list;
   }
 
   Future<String> send(SendPort sendPort) {
     final receivePort = new RawReceivePort();
     receivePort.handler = (value) {
       receivePort.close();
-      if (value is Exception) {
-        _completer.completeError(value);
-      } else {
-        _completer.complete(value);
-      }
+      assert(value is String);
+      _completer.complete(value);
     };
     var keys = _makeAllString(params.keys.toList(growable:false));
     var values = _makeAllString(params.values.toList(growable:false));
     var request = new List(5)
         ..[0] = 0  // Make room for OOB message type.
         ..[1] = receivePort.sendPort
         ..[2] = method
         ..[3] = keys
         ..[4] = values;
-    sendIsolateServiceMessage(sendPort, request);
+    if (!sendIsolateServiceMessage(sendPort, request)) {
+      _completer.complete(JSON.encode({
+          'type': 'ServiceError',
+          'id': '',
+          'kind': 'InternalError',
+          'message': 'could not send message to isolate',

[Cutch, 2015/03/10 00:00:18]

might want to include the serial here.

+      }));
+    }
     return _completer.future;
   }
 
   Future<String> sendToVM() {
     final receivePort = new RawReceivePort();
     receivePort.handler = (value) {
       receivePort.close();
-      if (value is Exception) {
-        _completer.completeError(value);
-      } else {
-        _completer.complete(value);
-      }
+      assert(value is String);
+      _completer.complete(value);
     };
     var keys = _makeAllString(params.keys.toList(growable:false));
     var values = _makeAllString(params.values.toList(growable:false));
     var request = new List(5)
         ..[0] = 0  // Make room for OOB message type.
         ..[1] = receivePort.sendPort
         ..[2] = method
         ..[3] = keys
         ..[4] = values;
     sendRootServiceMessage(request);
     return _completer.future;
   }
 
   void setResponse(String response) {
     _completer.complete(response);
   }
 
   void setErrorResponse(String error) {
     _completer.complete(JSON.encode({
         'type': 'ServiceError',
         'id': '',
         'kind': 'RequestError',
         'message': error,
         'path': path,
         'params': params
     }));
   }
 }
 
-void sendIsolateServiceMessage(SendPort sp, List m)
+bool sendIsolateServiceMessage(SendPort sp, List m)
     native "VMService_SendIsolateServiceMessage";
 
 void sendRootServiceMessage(List m)
     native "VMService_SendRootServiceMessage";