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