+
+ /// spell checker state versioning support
+ typedef unsigned long int ChangeNumber ;
+ ChangeNumber changeNumber() const { return change_number_; }
+ void changeNumber(ChangeNumber value) { change_number_ = value; }
+ void nextChangeNumber() { ++change_number_; }
+ virtual void advanceChangeNumber() = 0;
+
+private:
+ ChangeNumber change_number_;