Decode the Dart message into a Dart_CMessage structure before calling the native port callback

runtime/include/dart_api.h

 // 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.
 
 #ifndef INCLUDE_DART_API_H_
 #define INCLUDE_DART_API_H_
 
 /** \mainpage Dart Embedding API Reference
  *
  * Dart is a class-based programming language for creating structured
@@ skipping 538 matching lines @@
  *
  * \return True if the message was posted.
  */
 DART_EXPORT bool Dart_Post(Dart_Port port_id, Dart_Handle object);
 
 /**
  * A native message handler.
  *
  * This handler is associated with a native port by calling
  * Dart_NewNativePort.
+ *
+ * The message received is decoded into the message structure. The
+ * lifetime of the message data is controlled by the caller. All the
+ * data references from the message are allocated by the caller and
+ * will be reclaimed when returning to it.
  */
+struct Dart_CMessage;

[siva, 2012/02/04 01:55:43]

Why not move the section
/** Message sending/receiving from native code */
over here that way you don't have to forward declare struct Dart_CMessage.

Also the native handlers etc. are related to sending/receiving messages from a
native thread.

[Søren Gjesse, 2012/02/06 16:25:52]

Done.

 typedef void (*Dart_NativeMessageHandler)(Dart_Port dest_port_id,
                                           Dart_Port reply_port_id,
-                                          uint8_t* data);
-// TODO(turnidge): Make this function take more appropriate arguments.
+                                          Dart_CMessage* message);
 
 /**
  * Creates a new native port.  When messages are received on this
  * native port, then they will be dispatched to the provided native
  * message handler.
  *
  * \param name The name of this port in debugging messages.
  * \param handler The C handler to run when messages arrive on the port.
  * \param handle_concurrently Is it okay to process requests on this
  *                            native port concurrently?
@@ skipping 890 matching lines @@
 /**
  * A Dart_CMessage is used for receiving and sending messages from
  * native code not running in an isolate. A message contains an object
  * graph represented as Dart_CObject structures rooted as the provided
  * root.
  *
  * For information on the lifetime of this data, when provided in
  * callbacks, see the documentation for the individual callbacks.
  */
 struct Dart_CMessage {
   Dart_CObject* root;

[siva, 2012/02/04 01:55:43]

I am beginning to wonder if we need "struct Dart_CMessage" and
instead use Dart_CObject* directly as a param to NativeMessageHandler.

[Søren Gjesse, 2012/02/06 16:25:52]

Mads and I also discussed this Friday. And as it does not add any value - except
for an additional indirection, so I have removed it and uses Dart_CObject
directly.

 };
 
 
 #endif  // INCLUDE_DART_API_H_