Reduce copying in sending service responses.

runtime/vm/service.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 "vm/service.h"
 
 #include "include/dart_api.h"
 #include "include/dart_native_api.h"
 #include "platform/globals.h"
 
@@ skipping 11 matching lines @@
 #include "vm/native_arguments.h"
 #include "vm/native_symbol.h"
 #include "vm/object.h"
 #include "vm/object_graph.h"
 #include "vm/object_id_ring.h"
 #include "vm/object_store.h"
 #include "vm/parser.h"
 #include "vm/port.h"
 #include "vm/profiler_service.h"
 #include "vm/reusable_handles.h"
+#include "vm/safepoint.h"
 #include "vm/service_event.h"
 #include "vm/service_isolate.h"
 #include "vm/source_report.h"
 #include "vm/stack_frame.h"
 #include "vm/symbols.h"
 #include "vm/timeline.h"
 #include "vm/type_table.h"
 #include "vm/unicode.h"
 #include "vm/version.h"
 
@@ skipping 789 matching lines @@
   js.PostReply();
 }
 
 
 void Service::InvokeMethod(Isolate* I,
                            const Array& msg,
                            bool parameters_are_dart_objects) {
   Thread* T = Thread::Current();
   ASSERT(I == T->isolate());
   ASSERT(I != NULL);
+  ASSERT(T->execution_state() == Thread::kThreadInVM);
   ASSERT(!msg.IsNull());
   ASSERT(msg.Length() == 6);
 
   {
     StackZone zone(T);
     HANDLESCOPE(T);
 
     Instance& reply_port = Instance::Handle(Z);
     Instance& seq = String::Handle(Z);
     String& method_name = String::Handle(Z);
@@ skipping 337 matching lines @@
   EmbedderServiceHandler* next_;
 };
 
 
 void Service::EmbedderHandleMessage(EmbedderServiceHandler* handler,
                                     JSONStream* js) {
   ASSERT(handler != NULL);
   Dart_ServiceRequestCallback callback = handler->callback();
   ASSERT(callback != NULL);
   const char* response = NULL;
-  bool success = callback(js->method(), js->param_keys(), js->param_values(),
-                          js->num_params(), handler->user_data(), &response);
+  bool success;
+  {
+    TransitionVMToNative transition(Thread::Current());
+    success = callback(js->method(), js->param_keys(), js->param_values(),
+                       js->num_params(), handler->user_data(), &response);
+  }
   ASSERT(response != NULL);
   if (!success) {
     js->SetupError();
   }
   js->buffer()->AddString(response);
   js->PostReply();
   free(const_cast<char*>(response));
 }
 
 
@@ skipping 2931 matching lines @@
     if (strcmp(method_name, method.name) == 0) {
       return &method;
     }
   }
   return NULL;
 }
 
 #endif  // !PRODUCT
 
 }  // namespace dart