1// Copyright (c) 2010 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef BASE_STRINGS_NULLABLE_STRING16_H_
6#define BASE_STRINGS_NULLABLE_STRING16_H_
7
8#include <iosfwd>
9
10#include "base/base_export.h"
11#include "base/strings/string16.h"
12
13namespace base {
14
15// This class is a simple wrapper for string16 which also contains a null
16// state.  This should be used only where the difference between null and
17// empty is meaningful.
18class NullableString16 {
19 public:
20  NullableString16() : is_null_(true) { }
21  NullableString16(const string16& string, bool is_null)
22      : string_(string), is_null_(is_null) {
23  }
24
25  const string16& string() const { return string_; }
26  bool is_null() const { return is_null_; }
27
28 private:
29  string16 string_;
30  bool is_null_;
31};
32
33inline bool operator==(const NullableString16& a, const NullableString16& b) {
34  return a.is_null() == b.is_null() && a.string() == b.string();
35}
36
37inline bool operator!=(const NullableString16& a, const NullableString16& b) {
38  return !(a == b);
39}
40
41BASE_EXPORT std::ostream& operator<<(std::ostream& out,
42                                     const NullableString16& value);
43
44}  // namespace
45
46#endif  // BASE_STRINGS_NULLABLE_STRING16_H_
47