69 lines
2.1 KiB
C++
69 lines
2.1 KiB
C++
// Copyright (c) 2015 Amanieu d'Antras
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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#ifndef ASYNCXX_H_
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# error "Do not include this header directly, include <async++.h> instead."
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#endif
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namespace async {
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// Exception thrown by cancel_current_task()
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struct LIBASYNC_EXPORT_EXCEPTION task_canceled {};
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// A flag which can be used to request cancellation
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class cancellation_token {
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std::atomic<bool> state;
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public:
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cancellation_token()
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: state(false) {}
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// Non-copyable and non-movable
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cancellation_token(const cancellation_token&) = delete;
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cancellation_token& operator=(const cancellation_token&) = delete;
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bool is_canceled() const
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{
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bool s = state.load(std::memory_order_relaxed);
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if (s)
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std::atomic_thread_fence(std::memory_order_acquire);
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return s;
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}
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void cancel()
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{
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state.store(true, std::memory_order_release);
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}
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void reset()
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{
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state.store(false, std::memory_order_relaxed);
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}
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};
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// Interruption point, throws task_canceled if the specified token is set.
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inline void interruption_point(const cancellation_token& token)
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{
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if (token.is_canceled())
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LIBASYNC_THROW(task_canceled());
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}
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} // namespace async
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