Avoid trusting the length encoded in the Snapshot if there is an

runtime/lib/isolate.cc

 // Copyright (c) 2012, 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/bootstrap_natives.h"
 #include "vm/class_finalizer.h"
 #include "vm/dart.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_entry.h"
@@ skipping 24 matching lines @@
   intptr_t port_id_;
 };
 
 
 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);
 }
 
 
-static uint8_t* SerializeObject(const Instance& obj) {
-  uint8_t* result = NULL;
-  SnapshotWriter writer(Snapshot::kMessage, &result, &allocator);
-  writer.WriteObject(obj.raw());
-  writer.FinalizeBuffer();
-  return result;
-}
-
-
 static void StoreError(Isolate* isolate, const Object& obj) {
   ASSERT(obj.IsError());
   Error& error = Error::Handle();
   error ^= obj.raw();
   isolate->object_store()->set_sticky_error(error);
 }
 
 
 // TODO(turnidge): Move to DartLibraryCalls.
 RawObject* ReceivePortCreate(intptr_t port_id) {
@@ skipping 73 matching lines @@
   GET_NATIVE_ARGUMENT(Smi, id, arguments->At(0));
   PortMap::ClosePort(id.Value());
 }
 
 
 DEFINE_NATIVE_ENTRY(SendPortImpl_sendInternal_, 3) {
   GET_NATIVE_ARGUMENT(Smi, send_id, arguments->At(0));
   GET_NATIVE_ARGUMENT(Smi, reply_id, arguments->At(1));
   // TODO(iposva): Allow for arbitrary messages to be sent.
   GET_NATIVE_ARGUMENT(Instance, obj, arguments->At(2));
-  uint8_t* data = SerializeObject(obj);
+
+  uint8_t* data = NULL;
+  SnapshotWriter writer(Snapshot::kMessage, &data, &allocator);
+  writer.WriteObject(obj.raw());
+  intptr_t data_len = writer.FinalizeBuffer();

[siva, 2012/08/22 23:30:39]

As discussed offline we could probably get rid of the call to FinalizeBuffer
here and instead set data_len to writer.bytes_written().

[turnidge, 2012/08/23 18:37:57]

Done.

 
   // TODO(turnidge): Throw an exception when the return value is false?
   PortMap::PostMessage(new Message(
-      send_id.Value(), reply_id.Value(), data, Message::kNormalPriority));
+      send_id.Value(), reply_id.Value(), data, data_len,
+      Message::kNormalPriority));
 }
 
 
 static void ThrowIllegalArgException(const String& message) {
   GrowableArray<const Object*> args(1);
   args.Add(&message);
   Exceptions::ThrowByType(Exceptions::kIllegalArgument, args);
 }
 
 
@@ skipping 279 matching lines @@
 
 DEFINE_NATIVE_ENTRY(isolate_getPortInternal, 0) {
   const Object& port = Object::Handle(ReceivePortCreate(isolate->main_port()));
   if (port.IsError()) {
     Exceptions::PropagateError(Error::Cast(port));
   }
   arguments->SetReturn(port);
 }
 
 }  // namespace dart