First set of changes towards cleaning up the bytearray access APIs

vm/dart_api_impl.h

 // Copyright (c) 2011, 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_IMPL_H_
 #define VM_DART_API_IMPL_H_
 
 #include "vm/allocation.h"
 #include "vm/object.h"
 
@@ skipping 34 matching lines @@
     Isolate* tmp = (isolate);                                                  \
     CHECK_ISOLATE(tmp);                                                        \
     ApiState* state = tmp->api_state();                                        \
     ASSERT(state);                                                             \
     if (state->top_scope() == NULL) {                                          \
       FATAL1("%s expects to find a current scope. Did you forget to call "     \
            "Dart_EnterScope?", CURRENT_FUNC);                                  \
     }                                                                          \
   } while (0)
 
-#define DARTSCOPE_NOCHECKS(isolate)                                            \
-  Isolate* __temp_isolate__ = (isolate);                                       \
-  ASSERT(__temp_isolate__ != NULL);                                            \
-  HANDLESCOPE(__temp_isolate__);
-
 #define DARTSCOPE(isolate)                                                     \
   Isolate* __temp_isolate__ = (isolate);                                       \
   CHECK_ISOLATE_SCOPE(__temp_isolate__);                                       \
   HANDLESCOPE(__temp_isolate__);
 
 
 const char* CheckIsolateState(Isolate *isolate);
 
 void SetupErrorResult(Dart_Handle* handle);
 
@@ skipping 32 matching lines @@
   static FinalizablePersistentHandle* UnwrapAsPrologueWeakPersistentHandle(
       const ApiState& state,
       Dart_Handle object);
 
   // Casts the internal Isolate* type to the external Dart_Isolate type.
   static Dart_Isolate CastIsolate(Isolate* isolate);
 
   // Gets the handle used to designate successful return.
   static Dart_Handle Success(Isolate* isolate);
 
+  // Sets up the callback error object after initializing an Isolate. This
+  // object is pre-created because we will not be able to allocate this
+  // object when the error actually occurs. When the error occurs there will
+  // be outstanding acquires to internal data pointers making it unsafe to
+  // allocate objects on the dart heap.
+  static void SetupCallbackError(Isolate* isolate);
+
+  // Gets the handle which holds the pre-created callback error object.
+  static Dart_Handle CallbackError(Isolate* isolate);
+
   // Returns true if the handle holds a Smi.
   static bool IsSmi(Dart_Handle handle) {
     // TODO(turnidge): Assumes RawObject* is at offset zero.  Fix.
     RawObject* raw = *(reinterpret_cast<RawObject**>(handle));
     return !raw->IsHeapObject();
   }
 
   // Returns the value of a Smi.
   static intptr_t SmiValue(Dart_Handle handle) {
     // TODO(turnidge): Assumes RawObject* is at offset zero.  Fix.
@@ skipping 46 matching lines @@
   }
   ~IsolateSaver() {
     Isolate::SetCurrent(saved_isolate_);
   }
  private:
   Isolate* saved_isolate_;
 
   DISALLOW_COPY_AND_ASSIGN(IsolateSaver);
 };
 
+// Start a scope in which no Dart API call backs are allowed.
+#define START_NO_CALLBACK_SCOPE(isolate)                                       \
+  isolate->IncrementNoCallbackScopeDepth()
+
+// End a no Dart API call backs Scope.
+#define END_NO_CALLBACK_SCOPE(isolate)                                         \
+  isolate->DecrementNoCallbackScopeDepth()
+
+#define CHECK_CALLBACK_STATE(isolate)                                          \
+  if (isolate->no_callback_scope_depth() != 0) {                               \
+    return reinterpret_cast<Dart_Handle>(Api::CallbackError(isolate));         \
+  }                                                                            \
+
 }  // namespace dart.
 
 #endif  // VM_DART_API_IMPL_H_