michael@0: // Copyright (c) 2010 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: 
michael@0: #ifndef BASE_STRINGS_NULLABLE_STRING16_H_
michael@0: #define BASE_STRINGS_NULLABLE_STRING16_H_
michael@0: 
michael@0: #include <iosfwd>
michael@0: 
michael@0: #include "base/base_export.h"
michael@0: #include "base/strings/string16.h"
michael@0: 
michael@0: namespace base {
michael@0: 
michael@0: // This class is a simple wrapper for string16 which also contains a null
michael@0: // state.  This should be used only where the difference between null and
michael@0: // empty is meaningful.
michael@0: class NullableString16 {
michael@0:  public:
michael@0:   NullableString16() : is_null_(true) { }
michael@0:   NullableString16(const string16& string, bool is_null)
michael@0:       : string_(string), is_null_(is_null) {
michael@0:   }
michael@0: 
michael@0:   const string16& string() const { return string_; }
michael@0:   bool is_null() const { return is_null_; }
michael@0: 
michael@0:  private:
michael@0:   string16 string_;
michael@0:   bool is_null_;
michael@0: };
michael@0: 
michael@0: inline bool operator==(const NullableString16& a, const NullableString16& b) {
michael@0:   return a.is_null() == b.is_null() && a.string() == b.string();
michael@0: }
michael@0: 
michael@0: inline bool operator!=(const NullableString16& a, const NullableString16& b) {
michael@0:   return !(a == b);
michael@0: }
michael@0: 
michael@0: BASE_EXPORT std::ostream& operator<<(std::ostream& out,
michael@0:                                      const NullableString16& value);
michael@0: 
michael@0: }  // namespace
michael@0: 
michael@0: #endif  // BASE_STRINGS_NULLABLE_STRING16_H_