// DefaultValue.hh // Copyright (c) 2007 Fluxbox Team (fluxgen at fluxbox dot org) // // Permission is hereby granted, free of charge, to any person obtaining a // copy of this software and associated documentation files (the "Software"), // to deal in the Software without restriction, including without limitation // the rights to use, copy, modify, merge, publish, distribute, sublicense, // and/or sell copies of the Software, and to permit persons to whom the // Software is furnished to do so, subject to the following conditions: // // The above copyright notice and this permission notice shall be included in // all copies or substantial portions of the Software. // // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL // THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER // DEALINGS IN THE SOFTWARE. #ifndef FBTK_DEFAULTVALUE_HH #define FBTK_DEFAULTVALUE_HH #include "Accessor.hh" namespace FbTk { // class for overriding default values and restoring them later // Ret = type of value that gets returned // Def = type of default value -- may be Accessor<Ret> &, for example template <typename Ret, typename Def=Ret &> class DefaultValue: public Accessor<Ret> { public: DefaultValue(const Def def): m_default(def), m_actual(def), m_use_default(true) { } void restoreDefault() { m_use_default = true; } bool isDefault() const { return m_use_default; } DefaultValue<Ret, Def> &operator =(const Ret &val) { m_use_default = false; m_actual = val; return *this; } operator Ret() const { return m_use_default ? m_default : m_actual; } private: const Def m_default; Ret m_actual; bool m_use_default; }; } // end namespace FbTk #endif // FBTK_DEFAULTVALUE_HH