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

runtime/vm/dart_api_message.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 VM_DART_API_MESSAGE_H_
+#define VM_DART_API_MESSAGE_H_
+
+#include "vm/dart_api_state.h"
+#include "vm/snapshot.h"
+
+namespace dart {
+
+// Use this C structure for reading internal objects in the serialized
+// data. These are objects that we need to process in order to
+// generate the Dart_CObject graph but that we don't want to expose in
+// that graph.
+// TODO(sjesse): Remove this when message serialization format is
+// updated.
+struct Dart_CObject_Internal : public Dart_CObject {
+  enum Type {
+    kTypeArguments = Dart_CObject::kNumberOfTypes,
+    kDynamicType,
+  };
+};
+
+
+// Reads a message snapshot into a C structure.
+class ApiMessageReader : public BaseReader {
+ public:
+  ApiMessageReader(const uint8_t* buffer, intptr_t length, ReAlloc alloc);
+  ~ApiMessageReader() { }
+
+  Dart_CObject* ReadMessage();
+
+ private:
+  // Allocates a Dart_CObject object.
+  Dart_CObject* AllocateDartCObject();
+  // 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.
+  Dart_CObject* AllocateDartCObjectNull();
+  // 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.
+  Dart_CObject* AllocateDartCObjectInt32(int32_t value);
+  // Allocates a Dart_CObject object for a double.
+  Dart_CObject* AllocateDartCObjectDouble(double value);
+  // Allocates a Dart_CObject object for string data.
+  Dart_CObject* AllocateDartCObjectString(intptr_t length);
+  // 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);
+  Dart_CObject* ReadIndexedObject(intptr_t object_id);
+  Dart_CObject* ReadObject();
+
+  // Add object to backward references.
+  void AddBackwardReference(intptr_t id, Dart_CObject* obj);
+
+  Dart_CObject_Internal* AsInternal(Dart_CObject* object) {
+    ASSERT(object->type >= Dart_CObject::kNumberOfTypes);
+    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.
+  ReAlloc alloc_;
+  ApiGrowableArray<Dart_CObject*> backward_references_;
+
+  Dart_CObject type_arguments_marker;
+  Dart_CObject dynamic_type_marker;
+};
+
+}  // namespace dart
+
+#endif  // VM_DART_API_MESSAGE_H_