120 lines
2.8 KiB
C++
120 lines
2.8 KiB
C++
/* vim: set sw=4 sts=4 et foldmethod=syntax : */
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/*
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* Copyright (c) 2005, 2006, 2007, 2008 Ciaran McCreesh
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*
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* This file is part of the Paludis package manager. Paludis is free software;
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* you can redistribute it and/or modify it under the terms of the GNU General
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* Public License version 2, as published by the Free Software Foundation.
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*
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* Paludis is distributed in the hope that it will be useful, but WITHOUT ANY
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* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
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* Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef PALUDIS_GUARD_PALUDIS_SAVE_HH
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#define PALUDIS_GUARD_PALUDIS_SAVE_HH 1
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#include <paludis/util/attributes.hh>
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#include <functional>
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/** \file
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* Declarations for the Save and RunOnDestruction classes.
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*
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* \ingroup g_utils
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*
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* \section Examples
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*
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* - None at this time.
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*/
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namespace paludis
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{
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/**
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* Save the value of a particular variable and assign it a new value for the
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* duration of the Save instance's lifetime (RAII, see \ref EffCpp item 13 or
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* \ref TCppPL section 14.4).
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*
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* \ingroup g_utils
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* \nosubgrouping
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*/
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template <typename T_>
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class Save
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{
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private:
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T_ * const _ptr;
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const T_ _value;
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Save(const Save &);
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void operator= (const Save &);
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public:
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///\name Basic operations
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///\{
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/**
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* Constructor.
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*/
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Save(T_ * const p) :
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_ptr(p),
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_value(*p)
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{
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}
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/**
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* Constructor, with convenience assignment to new_value.
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*/
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Save(T_ * const p, const T_ & new_value) :
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_ptr(p),
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_value(*p)
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{
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*p = new_value;
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}
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/**
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* Destructor.
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*/
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~Save()
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{
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*_ptr = _value;
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}
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///\}
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};
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/**
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* Run the supplied function when the class is destructed.
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*
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* \ingroup g_utils
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* \since 0.26
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*/
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class PALUDIS_VISIBLE RunOnDestruction
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{
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private:
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RunOnDestruction(const RunOnDestruction &);
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void operator= (const RunOnDestruction &);
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const std::function<void ()> _f;
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public:
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RunOnDestruction(const std::function<void ()> & f) :
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_f(f)
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{
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}
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~RunOnDestruction()
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{
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_f();
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}
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};
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}
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#endif
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