third_party/WebKit/Source/core/typed_arrays/DOMArrayPiece.h

// 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.

#ifndef DOMArrayPiece_h
#define DOMArrayPiece_h

#include "core/typed_arrays/DOMArrayBuffer.h"
#include "core/typed_arrays/DOMArrayBufferView.h"
#include "platform/wtf/typed_arrays/ArrayPiece.h"

namespace blink {

class ArrayBufferOrArrayBufferView;

// This class is for passing around un-owned bytes as a pointer + length.
// It supports implicit conversion from several other data types.
//
// ArrayPiece has the concept of being "null". This is different from an empty
// byte range. It is invalid to call methods other than isNull() on such
// instances.
//
// IMPORTANT: The data contained by ArrayPiece is NOT OWNED, so caution must be
//            taken to ensure it is kept alive.
class CORE_EXPORT DOMArrayPiece : public WTF::ArrayPiece {
  DISALLOW_NEW();

 public:
  enum InitWithUnionOption {
    // Initialize this object as "null" when initialized with an union which
    // holds null.
    kTreatNullAsNull,
    // Initialize this object so this points to null pointer with zero size
    // when initialized with an union which holds null.
    kAllowNullPointToNullWithZeroSize,
  };

  DOMArrayPiece() = default;
  DOMArrayPiece(DOMArrayBuffer* buffer) : ArrayPiece(buffer->Buffer()) {}
  DOMArrayPiece(DOMArrayBufferView* view) : ArrayPiece(view->View()) {}
  DOMArrayPiece(const ArrayBufferOrArrayBufferView&,
                InitWithUnionOption = kTreatNullAsNull);

  bool operator==(const DOMArrayBuffer& other) const {
    return ByteLength() == other.ByteLength() &&
           memcmp(Data(), other.Data(), ByteLength()) == 0;
  }

  bool operator==(const DOMArrayBufferView& other) const {
    return ByteLength() == other.byteLength() &&
           memcmp(Data(), other.BaseAddress(), ByteLength()) == 0;
  }
};

}  // namespace blink

#endif  // DOMArrayPiece_h