third_party/blink/renderer/core/typed_arrays/dom_data_view.cc

// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "third_party/blink/renderer/core/typed_arrays/dom_data_view.h"

#include "base/numerics/checked_math.h"
#include "third_party/blink/renderer/bindings/core/v8/v8_array_buffer.h"
#include "third_party/blink/renderer/core/typed_arrays/array_buffer/array_buffer_view.h"
#include "third_party/blink/renderer/platform/bindings/dom_data_store.h"

namespace blink {

namespace {

class DataView final : public ArrayBufferView {
 public:
  static scoped_refptr<DataView> Create(ArrayBuffer* buffer,
                                        size_t byte_offset,
                                        size_t byte_length) {
    base::CheckedNumeric<size_t> checked_max = byte_offset;
    checked_max += byte_length;
    CHECK_LE(checked_max.ValueOrDie(), buffer->ByteLengthAsSizeT());
    return base::AdoptRef(new DataView(buffer, byte_offset, byte_length));
  }

  size_t ByteLengthAsSizeT() const override {
    return !IsDetached() ? raw_byte_length_ : 0;
  }
  ViewType GetType() const override { return kTypeDataView; }
  unsigned TypeSize() const override { return 1; }

 protected:
  void Detach() override {
    ArrayBufferView::Detach();
    raw_byte_length_ = 0;
  }

 private:
  DataView(ArrayBuffer* buffer, size_t byte_offset, size_t byte_length)
      : ArrayBufferView(buffer, byte_offset), raw_byte_length_(byte_length) {}

  // It may be stale after Detach. Use ByteLengthAsSizeT instead.
  size_t raw_byte_length_;
};

}  // anonymous namespace

DOMDataView* DOMDataView::Create(DOMArrayBufferBase* buffer,
                                 size_t byte_offset,
                                 size_t byte_length) {
  scoped_refptr<DataView> data_view =
      DataView::Create(buffer->Buffer(), byte_offset, byte_length);
  return MakeGarbageCollected<DOMDataView>(data_view, buffer);
}

v8::Local<v8::Value> DOMDataView::Wrap(v8::Isolate* isolate,
                                       v8::Local<v8::Object> creation_context) {
  DCHECK(!DOMDataStore::ContainsWrapper(this, isolate));

  const WrapperTypeInfo* wrapper_type_info = this->GetWrapperTypeInfo();
  v8::Local<v8::Value> v8_buffer = ToV8(buffer(), creation_context, isolate);
  if (v8_buffer.IsEmpty())
    return v8::Local<v8::Object>();
  DCHECK(v8_buffer->IsArrayBuffer());

  v8::Local<v8::Object> wrapper =
      v8::DataView::New(v8_buffer.As<v8::ArrayBuffer>(), byteOffsetAsSizeT(),
                        byteLengthAsSizeT());

  return AssociateWithWrapper(isolate, wrapper_type_info, wrapper);
}

}  // namespace blink