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 13 namespace 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. 18 class NullableString16 { 19 public: NullableString16()20 NullableString16() : is_null_(true) { } NullableString16(const string16 & string,bool is_null)21 NullableString16(const string16& string, bool is_null) 22 : string_(string), is_null_(is_null) { 23 } 24 string()25 const string16& string() const { return string_; } is_null()26 bool is_null() const { return is_null_; } 27 28 private: 29 string16 string_; 30 bool is_null_; 31 }; 32 33 inline bool operator==(const NullableString16& a, const NullableString16& b) { 34 return a.is_null() == b.is_null() && a.string() == b.string(); 35 } 36 37 inline bool operator!=(const NullableString16& a, const NullableString16& b) { 38 return !(a == b); 39 } 40 41 BASE_EXPORT std::ostream& operator<<(std::ostream& out, 42 const NullableString16& value); 43 44 } // namespace base 45 46 #endif // BASE_STRINGS_NULLABLE_STRING16_H_ 47