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https://github.com/libretro/beetle-psx-libretro.git
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101 lines
2.3 KiB
C++
101 lines
2.3 KiB
C++
/* Copyright (c) 2017-2018 Hans-Kristian Arntzen
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in 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,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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#pragma once
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#include <condition_variable>
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#include <mutex>
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#include <utility>
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#include "read_write_lock.hpp"
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namespace Util
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{
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template <typename T>
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class AsyncObjectSink
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{
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public:
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AsyncObjectSink()
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{
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has_object.store(false);
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}
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auto get_nowait()
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{
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spin.lock_read();
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auto ret = object.get();
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spin.unlock_read();
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return ret;
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}
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auto get()
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{
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if (has_object.load(std::memory_order_acquire))
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{
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return get_nowait();
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}
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else
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{
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{
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std::unique_lock<std::mutex> holder{lock};
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cond.wait(holder, [&]()
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{
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return async_object_exists;
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});
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}
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return get_nowait();
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}
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}
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T write_object(T new_object)
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{
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spin.lock_write();
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std::swap(object, new_object);
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if (!has_object.exchange(true))
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{
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std::lock_guard<std::mutex> holder{lock};
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async_object_exists = true;
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cond.notify_all();
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}
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spin.unlock_write();
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return new_object;
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}
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void reset()
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{
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spin.lock_write();
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std::lock_guard<std::mutex> holder{lock};
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async_object_exists = false;
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has_object.store(false);
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object = {};
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spin.unlock_write();
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}
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private:
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T object;
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std::condition_variable cond;
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std::mutex lock;
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Util::RWSpinLock spin;
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std::atomic_bool has_object;
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bool async_object_exists = false;
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};
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}
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