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ccc4eb8530
The idea was borrowed from http://wg21.link/p0052 scope_exit class is a helper, its name is hidden from user in the namespace detail. Alternative implementation of scope_exit with std::function looks slower on goldbolt.org as it may require allocation, etc. scope_exit doesn't need to own a callable, so beeing a pointer is enough. And std::decay produces such a pointer from callable.
66 lines
1.6 KiB
C++
66 lines
1.6 KiB
C++
/*
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Copyright (c) 2020, MariaDB
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; version 2 of
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the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA
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*/
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#pragma once
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#include <type_traits>
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#include <utility>
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namespace detail
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{
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template <typename Callable> class scope_exit
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{
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public:
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template <typename F>
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explicit scope_exit(F &&f) : function_(std::forward<F>(f))
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{
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}
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scope_exit(scope_exit &&rhs)
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: function_(std::move(rhs.function_)), engaged_(rhs.engaged_)
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{
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rhs.release();
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}
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scope_exit(const scope_exit &)= delete;
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scope_exit &operator=(scope_exit &&)= delete;
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scope_exit &operator=(const scope_exit &)= delete;
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void release() { engaged_= false; }
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~scope_exit()
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{
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if (engaged_)
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function_();
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}
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private:
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Callable function_;
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bool engaged_= true;
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};
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} // end namespace detail
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template <typename Callable>
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detail::scope_exit<typename std::decay<Callable>::type>
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make_scope_exit(Callable &&f)
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{
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return detail::scope_exit<typename std::decay<Callable>::type>(
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std::forward<Callable>(f));
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}
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