45 lines
950 B
C++
45 lines
950 B
C++
//
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// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2020
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#pragma once
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#include "td/utils/port/thread_local.h"
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namespace td {
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template <class Impl>
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class Context {
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public:
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static Impl *get() {
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return context_;
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}
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class Guard {
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public:
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explicit Guard(Impl *new_context) {
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old_context_ = context_;
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context_ = new_context;
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}
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~Guard() {
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context_ = old_context_;
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}
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Guard(const Guard &) = delete;
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Guard &operator=(const Guard &) = delete;
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Guard(Guard &&) = delete;
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Guard &operator=(Guard &&) = delete;
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private:
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Impl *old_context_;
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};
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private:
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static TD_THREAD_LOCAL Impl *context_;
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};
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template <class Impl>
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TD_THREAD_LOCAL Impl *Context<Impl>::context_;
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} // namespace td
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