File indexing completed on 2024-05-19 04:25:10

 /*
  *  SPDX-FileCopyrightText: 2023 Dmitry Kazakov <dimula73@gmail.com>
  *
  *  SPDX-License-Identifier: GPL-2.0-or-later
  */
 
 #ifndef KISVALUECACHE_H
 #define KISVALUECACHE_H
 
 #include <optional>
 
 /**
  * A simple class for cache-like structures. It should be parametrized
  * with a policy-class that has `value_type initialize()` method, which
  * would be used for initializing the cache.
  */
 template <typename Initializer>
 struct KisValueCache : Initializer
 {
     using value_type = decltype(std::declval<Initializer>().initialize());
 
     template <typename ...Args>
     KisValueCache(Args... args)
         : Initializer(args...)
     {
     }
 
     const value_type& value() {
         if (!m_value) {
             m_value = Initializer::initialize();
         }
 
         return *m_value;
     }
 
     operator const value_type&() const {
         return value();
     }
 
     bool isValid() const {
         return bool(m_value);
     }
 
     void clear() {
         m_value = std::nullopt;
     }
 
 private:
     std::optional<value_type> m_value;
 };
 
 #endif // KISVALUECACHE_H