77 lines
2.1 KiB
C++
77 lines
2.1 KiB
C++
/* vim: set sw=4 sts=4 et foldmethod=syntax : */
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/*
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* Copyright (c) 2008, 2009 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_UTIL_DEFERRED_CONSTRUCTION_PTR_HH
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#define PALUDIS_GUARD_PALUDIS_UTIL_DEFERRED_CONSTRUCTION_PTR_HH 1
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#include <paludis/util/deferred_construction_ptr-fwd.hh>
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#include <functional>
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namespace paludis
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{
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template <typename T_>
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class DeferredConstructionPtr
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{
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private:
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mutable T_ _ptr;
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std::function<T_ ()> _f;
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mutable bool _done;
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public:
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DeferredConstructionPtr(const std::function<T_ ()> & f) :
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_ptr(),
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_f(f),
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_done(false)
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{
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}
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DeferredConstructionPtr(const DeferredConstructionPtr & other) = default;
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DeferredConstructionPtr &
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operator= (const DeferredConstructionPtr & other)
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{
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if (this != &other)
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{
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_ptr = other._ptr;
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_f = other._f;
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_done = other._done;
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}
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return *this;
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}
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T_ operator-> () const
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{
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if (! _done)
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{
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_ptr = _f();
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_done = true;
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}
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return _ptr;
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}
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T_ value() const
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{
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return operator-> ();
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}
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};
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}
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#endif
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