53 lines
1.5 KiB
C++
53 lines
1.5 KiB
C++
/*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* Copyright 2018 Danny Robson <danny@nerdcruft.net>
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*/
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#ifndef CRUFT_UTIL_THREAD_SPINLOCK_HPP
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#define CRUFT_UTIL_THREAD_SPINLOCK_HPP
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#include <atomic>
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namespace util::thread {
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/// a CPU intensive, but lower latency, lock.
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///
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/// std::atomic_flag seems like it might have been a good option on which
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/// to base our implementation, but it appears potentially expensive to
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/// spin over without a cheap read operation.
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///
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/// satisfies BasicLockable.
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class spinlock {
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public:
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spinlock ();
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spinlock (spinlock &&);
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spinlock& operator= (spinlock &&);
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spinlock (const spinlock&) = delete;
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spinlock& operator= (const spinlock&) = delete;
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void lock ();
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void unlock ();
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private:
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static_assert (
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std::atomic<bool>::is_always_lock_free,
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"we require a lock free primitive or the entire point is moot"
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);
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std::atomic<bool> held;
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};
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};
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#endif
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