Handle TypedDataView objects in Dart_TypedDataAcquireData and

runtime/vm/dart_api_impl.cc

Index: runtime/vm/dart_api_impl.cc
===================================================================
--- runtime/vm/dart_api_impl.cc	(revision 20344)
+++ runtime/vm/dart_api_impl.cc	(working copy)
@@ -2333,46 +2333,57 @@
       type = kByteData;
       break;
     case kTypedDataInt8ArrayCid :
+    case kTypedDataInt8ArrayViewCid :
     case kExternalTypedDataInt8ArrayCid :
       type = kInt8;
       break;
     case kTypedDataUint8ArrayCid :
+    case kTypedDataUint8ArrayViewCid :
     case kExternalTypedDataUint8ArrayCid :
       type = kUint8;
       break;
     case kTypedDataUint8ClampedArrayCid :
+    case kTypedDataUint8ClampedArrayViewCid :
     case kExternalTypedDataUint8ClampedArrayCid :
       type = kUint8Clamped;
       break;
     case kTypedDataInt16ArrayCid :
+    case kTypedDataInt16ArrayViewCid :
     case kExternalTypedDataInt16ArrayCid :
       type = kInt16;
       break;
     case kTypedDataUint16ArrayCid :
+    case kTypedDataUint16ArrayViewCid :
     case kExternalTypedDataUint16ArrayCid :
       type = kUint16;
       break;
     case kTypedDataInt32ArrayCid :
+    case kTypedDataInt32ArrayViewCid :
     case kExternalTypedDataInt32ArrayCid :
       type = kInt32;
       break;
     case kTypedDataUint32ArrayCid :
+    case kTypedDataUint32ArrayViewCid :
     case kExternalTypedDataUint32ArrayCid :
       type = kUint32;
       break;
     case kTypedDataInt64ArrayCid :
+    case kTypedDataInt64ArrayViewCid :
     case kExternalTypedDataInt64ArrayCid :
       type = kInt64;
       break;
     case kTypedDataUint64ArrayCid :
+    case kTypedDataUint64ArrayViewCid :
     case kExternalTypedDataUint64ArrayCid :
       type = kUint64;
       break;
     case kTypedDataFloat32ArrayCid :
+    case kTypedDataFloat32ArrayViewCid :
     case kExternalTypedDataFloat32ArrayCid :
       type = kFloat32;
       break;
     case kTypedDataFloat64ArrayCid :
+    case kTypedDataFloat64ArrayViewCid :
     case kExternalTypedDataFloat64ArrayCid :
       type = kFloat64;
       break;
@@ -2386,7 +2397,8 @@
 
 DART_EXPORT Dart_TypedData_Type Dart_GetTypeOfTypedData(Dart_Handle object) {
   intptr_t class_id = Api::ClassId(object);
-  if (!RawObject::IsTypedDataClassId(class_id)) {
+  if (!RawObject::IsTypedDataClassId(class_id) &&
+      !RawObject::IsTypedDataViewClassId(class_id)) {
     return kInvalid;
   }
   return GetType(class_id);
@@ -2582,6 +2594,7 @@
   DARTSCOPE(isolate);
   intptr_t class_id = Api::ClassId(object);
   if (!RawObject::IsExternalTypedDataClassId(class_id) &&
+      !RawObject::IsTypedDataViewClassId(class_id) &&
       !RawObject::IsTypedDataClassId(class_id)) {
     RETURN_TYPE_ERROR(isolate, object, 'TypedData');
   }
@@ -2602,15 +2615,33 @@
         Api::UnwrapExternalTypedDataHandle(isolate, object);
     ASSERT(!obj.IsNull());
     *len = obj.Length();
-    *data = reinterpret_cast<void*>(obj.DataAddr(0));
-  } else {
+    *data = obj.DataAddr(0);
+  } else if (RawObject::IsTypedDataClassId(class_id)) {
     // Regular typed data object, set up some GC and API callback guards.
     const TypedData& obj = Api::UnwrapTypedDataHandle(isolate, object);
     ASSERT(!obj.IsNull());
     *len = obj.Length();
     isolate->IncrementNoGCScopeDepth();
     START_NO_CALLBACK_SCOPE(isolate);
-    *data = reinterpret_cast<void*>(obj.DataAddr(0));
+    *data = obj.DataAddr(0);
+  } else {
+    // typed data view object, set up some GC and API callback guards.
+    // TODO(asiva): Have to come up with a scheme to directly access
+    // the fields using offsets for a more efficient implementation.

[Ivan Posva, 2013/03/22 04:50:01]

How about making class _TypedListView known to the VM in a similar manner to the
way class _TypedList is partially implemented in the VM.

[siva, 2013/03/25 17:20:35]

I thought about this but for now choose against adding two more classes in the
VM (in this case we would need to setup the offsets in the VM code and have some
verification to ensure that the Dart fields and the VM assumptions match).

Maybe if this turns out to be super hot entrypoint we could consider that.

On 2013/03/22 04:50:01, Ivan Posva wrote:

+    Dart_Handle field_name = Dart_NewStringFromCString("length");
+    Dart_Handle field_value = Dart_GetField(object, field_name);
+    ASSERT(Api::IsSmi(field_value));
+    *len = Api::SmiValue(field_value);
+    field_name = Dart_NewStringFromCString("offsetInBytes");
+    field_value = Dart_GetField(object, field_name);
+    ASSERT(Api::IsSmi(field_value));
+    intptr_t offset_in_bytes = Api::SmiValue(field_value);
+    field_name = Dart_NewStringFromCString("_typeddata");
+    field_value = Dart_GetField(object, field_name);
+    const TypedData& obj = Api::UnwrapTypedDataHandle(isolate, field_value);
+    isolate->IncrementNoGCScopeDepth();
+    START_NO_CALLBACK_SCOPE(isolate);
+    *data = obj.DataAddr(offset_in_bytes);
   }
   return Api::Success(isolate);
 }
@@ -2621,6 +2652,7 @@
   DARTSCOPE(isolate);
   intptr_t class_id = Api::ClassId(object);
   if (!RawObject::IsExternalTypedDataClassId(class_id) &&
+      !RawObject::IsTypedDataViewClassId(class_id) &&
       !RawObject::IsTypedDataClassId(class_id)) {
     RETURN_TYPE_ERROR(isolate, object, 'TypedData');
   }