nullable_string16.h

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// Copyright (c) 2010 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 BASE_STRINGS_NULLABLE_STRING16_H_

#define BASE_STRINGS_NULLABLE_STRING16_H_

#include <iosfwd>

#include "base/base_export.h"

#include "base/optional.h"

#include "base/strings/string16.h"

#include "base/strings/string_util.h"

namespace base {

// This class is a simple wrapper for string16 which also contains a null

// state.  This should be used only where the difference between null and

// empty is meaningful.

class BASE_EXPORT NullableString16 {

 public:

  NullableString16();

  NullableString16(const NullableString16& other);

  NullableString16(NullableString16&& other);

  NullableString16(const string16& string, bool is_null);

  explicit NullableString16(Optional<string16> optional_string16);

  ~NullableString16();

  NullableString16& operator=(const NullableString16& other);

  NullableString16& operator=(NullableString16&& other);

  const string16& string() const {

    return string_ ? *string_ : EmptyString16();

  bool is_null() const { return !string_; }

  const Optional<string16>& as_optional_string16() const { return string_; }

 private:

  Optional<string16> string_;

};

inline bool operator==(const NullableString16& a, const NullableString16& b) {

  return a.as_optional_string16() == b.as_optional_string16();

inline bool operator!=(const NullableString16& a, const NullableString16& b) {

  return !(a == b);

BASE_EXPORT std::ostream& operator<<(std::ostream& out,

                                     const NullableString16& value);

}  // namespace base

#endif  // BASE_STRINGS_NULLABLE_STRING16_H_