When no service response is requested, send null back to the service isolate so it can cleanup

runtime/vm/json_stream.cc

 // 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.
 
 #include "platform/assert.h"
 
 #include "vm/dart_entry.h"
 #include "vm/debugger.h"
 #include "vm/json_stream.h"
 #include "vm/message.h"
@@ skipping 135 matching lines @@
   }
 }
 
 
 static uint8_t* allocator(uint8_t* ptr, intptr_t old_size, intptr_t new_size) {
   void* new_ptr = realloc(reinterpret_cast<void*>(ptr), new_size);
   return reinterpret_cast<uint8_t*>(new_ptr);
 }
 
 
+void JSONStream::PostNullReply(Dart_Port port) {
+  const Object& reply = Object::Handle(Object::null());
+  ASSERT(reply.IsNull());
+
+  uint8_t* data = NULL;
+  MessageWriter writer(&data, &allocator, false);
+  writer.WriteMessage(reply);
+  PortMap::PostMessage(new Message(port,
+                                   data,
+                                   writer.BytesWritten(),
+                                   Message::kNormalPriority));
+}
+
+
 void JSONStream::PostReply() {
   Dart_Port port = reply_port();
   ASSERT(port != ILLEGAL_PORT);
   set_reply_port(ILLEGAL_PORT);  // Prevent double replies.
   int64_t process_delta_micros = 0;
   if (FLAG_trace_service) {
     process_delta_micros = OS::GetCurrentTimeMicros() - setup_time_micros_;
   }
 
   if (seq_.IsString()) {
     const String& str = String::Cast(seq_);
     PrintProperty("id", str.ToCString());
   } else if (seq_.IsInteger()) {
     const Integer& integer = Integer::Cast(seq_);
     PrintProperty64("id", integer.AsInt64Value());
   } else if (seq_.IsDouble()) {
     const Double& dbl = Double::Cast(seq_);
     PrintProperty("id", dbl.value());
   } else if (seq_.IsNull()) {
     // JSON-RPC 2.0 says that a request with a null ID shouldn't get a reply.
+    PostNullReply(port);
     return;
   }
   buffer_.AddChar('}');
 
   const String& reply = String::Handle(String::New(ToCString()));
   ASSERT(!reply.IsNull());
 
   uint8_t* data = NULL;
   MessageWriter writer(&data, &allocator, false);
   writer.WriteMessage(reply);
@@ skipping 522 matching lines @@
   intptr_t len2 = OS::VSNPrint(p, len+1, format, args);
   va_end(args);
   ASSERT(len == len2);
   stream_->buffer_.AddChar('"');
   stream_->AddEscapedUTF8String(p);
   stream_->buffer_.AddChar('"');
   free(p);
 }
 
 }  // namespace dart