[builtins] Migrate the DataView constructor to C++.

src/builtins.cc

Index: src/builtins.cc
diff --git a/src/builtins.cc b/src/builtins.cc
index 474b76fc15567de1f04c4dfe65a5aa8edcb4143f..5436569027fb5aba1b52b9e73659ad0393a7c48a 100644
--- a/src/builtins.cc
+++ b/src/builtins.cc
@@ -2388,6 +2388,118 @@ BUILTIN(BooleanPrototypeValueOf) {
 
 
 // -----------------------------------------------------------------------------
+// ES6 section 24.2 DataView Objects
+
+
+// ES6 section 24.2.2 The DataView Constructor for the [[Call]] case.
+BUILTIN(DataViewConstructor) {
+  HandleScope scope(isolate);
+  THROW_NEW_ERROR_RETURN_FAILURE(
+      isolate,
+      NewTypeError(MessageTemplate::kConstructorNotFunction,
+                   isolate->factory()->NewStringFromAsciiChecked("DataView")));
+}
+
+
+// ES6 section 24.2.2 The DataView Constructor for the [[Construct]] case.
+BUILTIN(DataViewConstructor_ConstructStub) {
+  HandleScope scope(isolate);
+  Handle<JSFunction> target = args.target<JSFunction>();
+  Handle<JSReceiver> new_target = Handle<JSReceiver>::cast(args.new_target());
+  Handle<Object> buffer = args.atOrUndefined(isolate, 1);
+  Handle<Object> byte_offset = args.atOrUndefined(isolate, 2);
+  Handle<Object> byte_length = args.atOrUndefined(isolate, 3);
+
+  // 2. If Type(buffer) is not Object, throw a TypeError exception.
+  // 3. If buffer does not have an [[ArrayBufferData]] internal slot, throw a
+  //    TypeError exception.
+  if (!buffer->IsJSArrayBuffer()) {
+    THROW_NEW_ERROR_RETURN_FAILURE(
+        isolate, NewTypeError(MessageTemplate::kDataViewNotArrayBuffer));
+  }
+  Handle<JSArrayBuffer> array_buffer = Handle<JSArrayBuffer>::cast(buffer);
+
+  // 4. Let numberOffset be ? ToNumber(byteOffset).
+  Handle<Object> number_offset;
+  if (byte_offset->IsUndefined()) {
+    // We intentionally violate the specification at this point to allow
+    // for new DataView(buffer) invocations to be equivalent to the full
+    // new DataView(buffer, 0) invocation.
+    number_offset = handle(Smi::FromInt(0), isolate);
+  } else {
+    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, number_offset,
+                                       Object::ToNumber(byte_offset));
+  }
+
+  // 5. Let offset be ToInteger(numberOffset).
+  Handle<Object> offset;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, offset,
+                                     Object::ToInteger(isolate, number_offset));
+
+  // 6. If numberOffset ≠ offset or offset < 0, throw a RangeError exception.
+  if (number_offset->Number() != offset->Number() || offset->Number() < 0.0) {
+    THROW_NEW_ERROR_RETURN_FAILURE(
+        isolate, NewRangeError(MessageTemplate::kInvalidDataViewOffset));
+  }
+
+  // 7. If IsDetachedBuffer(buffer) is true, throw a TypeError exception.
+  // We currently violate the specification at this point.
+
+  // 8. Let bufferByteLength be the value of buffer's [[ArrayBufferByteLength]]
+  // internal slot.
+  double const buffer_byte_length = array_buffer->byte_length()->Number();
+
+  // 9. If offset > bufferByteLength, throw a RangeError exception
+  if (offset->Number() > buffer_byte_length) {
+    THROW_NEW_ERROR_RETURN_FAILURE(
+        isolate, NewRangeError(MessageTemplate::kInvalidDataViewOffset));
+  }
+
+  Handle<Object> view_byte_length;
+  if (byte_length->IsUndefined()) {
+    // 10. If byteLength is undefined, then
+    //       a. Let viewByteLength be bufferByteLength - offset.
+    view_byte_length =
+        isolate->factory()->NewNumber(buffer_byte_length - offset->Number());
+  } else {
+    // 11. Else,
+    //       a. Let viewByteLength be ? ToLength(byteLength).
+    //       b. If offset+viewByteLength > bufferByteLength, throw a RangeError
+    //          exception
+    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+        isolate, view_byte_length, Object::ToLength(isolate, byte_length));
+    if (offset->Number() + view_byte_length->Number() > buffer_byte_length) {
+      THROW_NEW_ERROR_RETURN_FAILURE(
+          isolate, NewRangeError(MessageTemplate::kInvalidDataViewLength));
+    }
+  }
+
+  // 12. Let O be ? OrdinaryCreateFromConstructor(NewTarget,
+  //     "%DataViewPrototype%", «[[DataView]], [[ViewedArrayBuffer]],
+  //     [[ByteLength]], [[ByteOffset]]»).
+  // 13. Set O's [[DataView]] internal slot to true.
+  Handle<JSObject> result;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result,
+                                     JSObject::New(target, new_target));
+  for (int i = 0; i < ArrayBufferView::kInternalFieldCount; ++i) {
+    Handle<JSDataView>::cast(result)->SetInternalField(i, Smi::FromInt(0));
+  }
+
+  // 14. Set O's [[ViewedArrayBuffer]] internal slot to buffer.
+  Handle<JSDataView>::cast(result)->set_buffer(*array_buffer);
+
+  // 15. Set O's [[ByteLength]] internal slot to viewByteLength.
+  Handle<JSDataView>::cast(result)->set_byte_length(*view_byte_length);
+
+  // 16. Set O's [[ByteOffset]] internal slot to offset.
+  Handle<JSDataView>::cast(result)->set_byte_offset(*offset);
+
+  // 17. Return O.
+  return *result;
+}
+
+
+// -----------------------------------------------------------------------------
 // ES6 section 20.3 Date Objects