101 lines
1.9 KiB
C++
101 lines
1.9 KiB
C++
/*
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This file is part of Telegram Desktop,
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the official desktop application for the Telegram messaging service.
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For license and copyright information please follow this link:
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https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
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*/
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#pragma once
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#include "base/algorithm.h"
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#include <atomic>
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namespace base {
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class binary_guard {
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public:
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binary_guard() = default;
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binary_guard(binary_guard &&other);
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binary_guard &operator=(binary_guard &&other);
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~binary_guard();
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binary_guard &operator=(std::nullptr_t);
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bool alive() const;
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binary_guard make_guard();
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explicit operator bool() const;
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private:
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void destroy();
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std::atomic<bool> *_bothAlive = nullptr;
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};
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inline binary_guard::binary_guard(binary_guard &&other)
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: _bothAlive(base::take(other._bothAlive)) {
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}
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inline binary_guard &binary_guard::operator=(binary_guard &&other) {
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if (this != &other) {
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destroy();
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_bothAlive = base::take(other._bothAlive);
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}
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return *this;
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}
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inline binary_guard::~binary_guard() {
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destroy();
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}
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inline binary_guard &binary_guard::operator=(std::nullptr_t) {
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destroy();
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return *this;
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}
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inline binary_guard::operator bool() const {
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return alive();
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}
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inline bool binary_guard::alive() const {
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return _bothAlive && _bothAlive->load();
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}
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inline void binary_guard::destroy() {
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if (const auto both = base::take(_bothAlive)) {
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auto old = true;
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if (!both->compare_exchange_strong(old, false)) {
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delete both;
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}
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}
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}
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inline binary_guard binary_guard::make_guard() {
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destroy();
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auto result = binary_guard();
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_bothAlive = result._bothAlive = new std::atomic<bool>(true);
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return result;
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}
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} // namespace base
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namespace crl {
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template <typename T, typename Enable>
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struct guard_traits;
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template <>
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struct guard_traits<base::binary_guard, void> {
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static base::binary_guard create(base::binary_guard value) {
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return value;
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}
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static bool check(const base::binary_guard &guard) {
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return guard.alive();
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}
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};
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} // namespace crl
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