72 lines
1.8 KiB
C++
72 lines
1.8 KiB
C++
//
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// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2023
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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 <atomic>
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#include <memory>
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namespace td {
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namespace detail {
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struct RawCancellationToken {
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std::atomic<bool> is_canceled_{false};
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};
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} // namespace detail
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class CancellationToken {
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public:
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explicit operator bool() const noexcept {
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// empty CancellationToken is never canceled
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if (!token_) {
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return false;
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}
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return token_->is_canceled_.load(std::memory_order_acquire);
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}
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CancellationToken() = default;
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explicit CancellationToken(std::shared_ptr<detail::RawCancellationToken> token) : token_(std::move(token)) {
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}
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private:
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std::shared_ptr<detail::RawCancellationToken> token_;
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};
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class CancellationTokenSource {
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public:
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CancellationTokenSource() = default;
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CancellationTokenSource(CancellationTokenSource &&other) noexcept : token_(std::move(other.token_)) {
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}
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CancellationTokenSource &operator=(CancellationTokenSource &&other) noexcept {
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cancel();
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token_ = std::move(other.token_);
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return *this;
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}
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CancellationTokenSource(const CancellationTokenSource &) = delete;
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CancellationTokenSource &operator=(const CancellationTokenSource &) = delete;
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~CancellationTokenSource() {
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cancel();
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}
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CancellationToken get_cancellation_token() {
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if (!token_) {
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token_ = std::make_shared<detail::RawCancellationToken>();
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}
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return CancellationToken(token_);
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}
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void cancel() {
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if (!token_) {
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return;
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}
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token_->is_canceled_.store(true, std::memory_order_release);
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token_.reset();
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}
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private:
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std::shared_ptr<detail::RawCancellationToken> token_;
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};
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} // namespace td
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