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+/* vim: set sw=4 sts=4 et foldmethod=syntax : */
+
+/*
+ * Copyright (c) 2005, 2006 Ciaran McCreesh <ciaran.mccreesh@blueyonder.co.uk>
+ *
+ * This file is part of the Paludis package manager. Paludis is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU General
+ * Public License version 2, as published by the Free Software Foundation.
+ *
+ * Paludis 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
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#ifndef PALUDIS_GUARD_PALUDIS_SAVE_HH
+#define PALUDIS_GUARD_PALUDIS_SAVE_HH 1
+
+#include <paludis/util/instantiation_policy.hh>
+
+/** \file
+ * Declarations for the Save class.
+ *
+ * \ingroup grpsave
+ */
+
+namespace paludis
+{
+ /**
+ * Save the value of a particular variable and assign it a new value for the
+ * duration of the Save instance's lifetime (RAII, see \ref EffCpp item 13 or
+ * \ref TCppPL section 14.4).
+ *
+ * \ingroup grpsave
+ */
+ template <typename T_>
+ class Save :
+ private InstantiationPolicy<Save<T_>, instantiation_method::NonCopyableTag>
+ {
+ private:
+ T_ * const _ptr;
+ const T_ _value;
+
+ public:
+ /**
+ * Constructor.
+ */
+ Save(T_ * const p) :
+ _ptr(p),
+ _value(*p)
+ {
+ }
+
+ /**
+ * Constructor, with convenience assignment to new_value.
+ */
+ Save(T_ * const p, const T_ & new_value) :
+ _ptr(p),
+ _value(*p)
+ {
+ *p = new_value;
+ }
+
+ /**
+ * Destructor.
+ */
+ ~Save()
+ {
+ *_ptr = _value;
+ }
+ };
+}
+
+#endif