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

runtime/vm/snapshot.h

Index: runtime/vm/snapshot.h
diff --git a/runtime/vm/snapshot.h b/runtime/vm/snapshot.h
index 166ea06ee89e899b0714b4203faf0dee7705f29d..cc793504a3339cf4792d51baa743aa858cccb892 100644
--- a/runtime/vm/snapshot.h
+++ b/runtime/vm/snapshot.h
@@ -421,29 +421,41 @@ struct Dart_CObject_Internal : public Dart_CObject {
 // Reads a message snapshot into C structure.
 class CMessageReader : public BaseReader {
  public:
+  // Creates a message reader where the allocated Dart_CMessage
+  // structure and all the allocated Dart_CObject structures are
+  // allocated using the supplied allocation function.
   CMessageReader(const uint8_t* buffer, intptr_t length, ReAlloc alloc);
+  // Creates a message reader where the allocated Dart_CMessage
+  // structure and all the allocated Dart_CObject structures are
+  // allocated in the supplied zone. The supplied zone will also be
+  // used for temporary allocations for message decoding.
+  CMessageReader(const uint8_t* buffer, intptr_t length, Zone* zone);

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

Ditto comment regarding this version of the constructor, do you really want
this,  can't we have an allocator that will do the same.

[Søren Gjesse, 2012/02/06 16:25:52]

See comment in native_message_handler.cc

   ~CMessageReader() { }
 
   Dart_CMessage* ReadMessage();
 
  private:
-  // Allocates a Dart_CObject object on the C heap.
+  // Allocate a piece of memory for the decoded message data.
+  uint8_t* Allocate(uint8_t* ptr, intptr_t old_size, intptr_t new_size);
+  // Allocates a Dart_CObject object.
   Dart_CObject* AllocateDartCObject();
-  // Allocates a Dart_CObject object with the specified type on the C heap.
+  // Allocates a Dart_CObject object with the specified type.
   Dart_CObject* AllocateDartCObject(Dart_CObject::Type type);
-  // Allocates a Dart_CObject object for the null object on the C heap.
+  // Allocates a Dart_CObject object for the null object.
   Dart_CObject* AllocateDartCObjectNull();
-  // Allocates a Dart_CObject object for a boolean object on the C heap.
+  // Allocates a Dart_CObject object for a boolean object.
   Dart_CObject* AllocateDartCObjectBool(bool value);
-  // Allocates a Dart_CObject object for for a 32-bit integer on the C heap.
+  // Allocates a Dart_CObject object for for a 32-bit integer.
   Dart_CObject* AllocateDartCObjectInt32(int32_t value);
-  // Allocates a Dart_CObject object for a double on the C heap.
+  // Allocates a Dart_CObject object for a double.
   Dart_CObject* AllocateDartCObjectDouble(double value);
-  // Allocates a Dart_CObject object for string data on the C heap.
+  // Allocates a Dart_CObject object for string data.
   Dart_CObject* AllocateDartCObjectString(intptr_t length);
-  // Allocates a C array of Dart_CObject objects on the C heap.
+  // Allocates a C array of Dart_CObject objects.
   Dart_CObject* AllocateDartCObjectArray(intptr_t length);
 
+  void Init();
+
   intptr_t LookupInternalClass(intptr_t class_header);
   Dart_CObject* ReadInlinedObject(intptr_t object_id);
   Dart_CObject* ReadObjectImpl(intptr_t header);
@@ -458,6 +470,10 @@ class CMessageReader : public BaseReader {
     return reinterpret_cast<Dart_CObject_Internal*>(object);
   }
 
+  // Allocation of the structures for the decoded message happens
+  // either in the supplied zone or using the supplied allocation
+  // function.
+  Zone* zone_;

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

Ditto comment.

   ReAlloc alloc_;
   GrowableArray<Dart_CObject*> backward_references_;