Split Base into LeanBase and Base.

Build not tested - intermediate commit.

include/dindexer-machinery/scantask/base.hpp

@@ -18,49 +18,51 @@
 #ifndef idCB253C1A5AFA46A18B8878ED4072CD96
 #define idCB253C1A5AFA46A18B8878ED4072CD96
 
+#include "dindexer-machinery/scantask/leanbase.hpp"
 #include <ciso646>
+#include <cassert>
 
 namespace mchlib {
 	namespace scantask {
 		template <typename T>
-		class Base {
+		class Base : public LeanBase<T> {
 		protected:
 			Base ( void );
 			virtual ~Base ( void ) noexcept = default;
 
 		public:
-			T& get_or_create ( void );
 			void clear_data ( void );
 
 		private:
 			virtual void on_data_destroy ( T& parData ) = 0;
 			virtual void on_data_create ( T& parData ) = 0;
 
+			virtual T& on_data_get ( void ) final;
+			virtual void on_data_fill ( void ) final;
+
+			using LeanBase<T>::unset_data_created;
+
 			T m_data;
-			bool m_data_created;
 		};
 
 		template <typename T>
-		Base<T>::Base() :
-			m_data_created(false)
-		{
+		Base<T>::Base() {
 		}
 
 		template <typename T>
-		T& Base<T>::get_or_create() {
-			if (not m_data_created) {
-				m_data_created = true;
-				this->on_data_create(m_data);
-			}
-			return m_data;
+		void Base<T>::on_data_fill() {
+			this->on_data_create(m_data);
 		}
 
 		template <typename T>
 		void Base<T>::clear_data() {
-			if (m_data_created) {
-				m_data_created = false;
-				this->on_data_destroy(m_data);
-			}
+			this->unset_data_created();
+			this->on_data_destroy(m_data);
+		}
+
+		template <typename T>
+		T& Base<T>::on_data_get() {
+			return m_data;
 		}
 	} //namespace scantask
 } //namespace mchlib

include/dindexer-machinery/scantask/leanbase.hpp

@@ -0,0 +1,67 @@
+/* Copyright 2015, 2016, Michele Santullo
+ * This file is part of "dindexer".
+ *
+ * "dindexer" is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * "dindexer" is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with "dindexer".  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef id982AF1D5C59C415584F56C1E6DDFE55E
+#define id982AF1D5C59C415584F56C1E6DDFE55E
+
+#include <ciso646>
+#include <cassert>
+
+namespace mchlib {
+	namespace scantask {
+		template <typename T>
+		class LeanBase {
+		protected:
+			LeanBase ( void );
+			virtual ~LeanBase ( void ) noexcept = default;
+
+			void unset_data_created ( void );
+
+		public:
+			T& get_or_create ( void );
+
+		private:
+			virtual void on_data_fill ( void ) = 0;
+			virtual T& on_data_get ( void ) = 0;
+
+			bool m_data_created;
+		};
+
+		template <typename T>
+		LeanBase<T>::LeanBase() :
+			m_data_created(false)
+		{
+		}
+
+		template <typename T>
+		T& LeanBase<T>::get_or_create() {
+			if (not m_data_created) {
+				m_data_created = true;
+				this->on_data_fill();
+			}
+			return this->on_data_get();
+		}
+
+		template <typename T>
+		void LeanBase<T>::unset_data_created() {
+			assert(m_data_created);
+			m_data_created = false;
+		}
+	} //namespace scantask
+} //namespace mchlib
+
+#endif