2a04dd5cc1
* Fix race condition in wait_for between calling atomic load
and condition_variable::wait_for, by protecting atomic store
with same mutex as AtomicCondition::wait_for.
* Subsequently, simplify the interface by removing notify_{one,all}.
condition_varaiable::notify_all is now automatically called in
`AtomicCondition::set(val)`.
76 lines
1.5 KiB
C++
76 lines
1.5 KiB
C++
// Author: Thomas Trapp - https://thomastrapp.com/
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// License: MIT
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#pragma once
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#include <atomic>
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#include <chrono>
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#include <condition_variable>
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#include <mutex>
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namespace sgnl {
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template<typename ValueType>
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class AtomicCondition
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{
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public:
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explicit AtomicCondition(ValueType val)
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: value_(val)
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, mutex_()
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, condvar_()
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{
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}
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ValueType get() const noexcept
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{
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return this->value_.load();
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}
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void set(ValueType val) noexcept
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{
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{
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// This ensures that wait_for is either
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// 1. not running, or
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// 2. in a waiting state
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// to avoid a data race between value_.load and cond_var.wait_for.
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std::unique_lock<std::mutex> lock(this->mutex_);
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this->value_.store(val);
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}
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this->condvar_.notify_all();
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}
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template<class Rep, class Period>
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void wait_for(const std::chrono::duration<Rep, Period>& time,
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ValueType val) const
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{
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std::unique_lock<std::mutex> lock(this->mutex_);
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while( this->value_.load() != val )
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if( this->condvar_.wait_for(lock, time) == std::cv_status::timeout )
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return;
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}
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template<class Rep, class Period, class Predicate>
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void wait_for(const std::chrono::duration<Rep, Period>& time,
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Predicate pred) const
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{
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std::unique_lock<std::mutex> lock(this->mutex_);
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while( !pred() )
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if( this->condvar_.wait_for(lock, time) == std::cv_status::timeout )
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return;
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}
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private:
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std::atomic<ValueType> value_;
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mutable std::mutex mutex_;
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mutable std::condition_variable condvar_;
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};
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} // namespace sgnl
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