mirror of https://github.com/Icinga/icinga2.git
120 lines
1.9 KiB
C++
120 lines
1.9 KiB
C++
/* Icinga 2 | (c) 2019 Icinga GmbH | GPLv2+ */
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#ifndef ATOMIC_H
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#define ATOMIC_H
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#include <atomic>
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#include <type_traits>
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#include <utility>
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namespace icinga
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{
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/**
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* Extends std::atomic with an atomic constructor.
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*
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* @ingroup base
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*/
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template<class T>
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class Atomic : public std::atomic<T> {
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public:
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/**
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* Like std::atomic#atomic, but operates atomically
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*
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* @param desired Initial value
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*/
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inline Atomic(T desired)
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{
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this->store(desired);
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}
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/**
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* Like std::atomic#atomic, but operates atomically
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*
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* @param desired Initial value
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* @param order Initial store operation's memory order
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*/
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inline Atomic(T desired, std::memory_order order)
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{
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this->store(desired, order);
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}
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};
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/**
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* Wraps T into a std::atomic<T>-like interface.
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*
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* @ingroup base
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*/
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template<class T>
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class NotAtomic
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{
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public:
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inline T load() const
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{
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return m_Value;
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}
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inline void store(T desired)
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{
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m_Value = std::move(desired);
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}
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T m_Value;
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};
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/**
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* Tells whether to use std::atomic<T> or NotAtomic<T>.
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*
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* @ingroup base
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*/
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template<class T>
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struct Atomicable
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{
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// Doesn't work with too old compilers.
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//static constexpr bool value = std::is_trivially_copyable<T>::value && sizeof(T) <= sizeof(void*);
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static constexpr bool value = (std::is_fundamental<T>::value || std::is_pointer<T>::value) && sizeof(T) <= sizeof(void*);
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};
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/**
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* Uses either std::atomic<T> or NotAtomic<T> depending on atomicable.
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*
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* @ingroup base
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*/
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template<bool atomicable>
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struct AtomicTemplate;
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template<>
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struct AtomicTemplate<false>
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{
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template<class T>
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struct tmplt
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{
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typedef NotAtomic<T> type;
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};
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};
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template<>
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struct AtomicTemplate<true>
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{
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template<class T>
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struct tmplt
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{
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typedef std::atomic<T> type;
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};
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};
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/**
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* Uses either std::atomic<T> or NotAtomic<T> depending on T.
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*
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* @ingroup base
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*/
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template<class T>
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struct EventuallyAtomic
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{
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typedef typename AtomicTemplate<Atomicable<T>::value>::template tmplt<T>::type type;
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};
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}
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#endif /* ATOMIC_H */
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