39 lines
875 B
C++
39 lines
875 B
C++
#ifndef __HL_SINGLETONE_H
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#define __HL_SINGLETONE_H
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#include <atomic>
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#include <mutex>
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template <class T>
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class SafeSingleton
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{
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protected:
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static std::atomic<T*> SharedInstance;
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static std::mutex mMutex;
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public:
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static T& instance()
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{
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T* tmp = SharedInstance.load(std::memory_order_relaxed);
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std::atomic_thread_fence(std::memory_order_acquire);
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if (tmp == nullptr)
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{
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std::lock_guard<std::mutex> lock(mMutex);
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tmp = SharedInstance.load(std::memory_order_relaxed);
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if (tmp == nullptr)
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{
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tmp = new T();
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std::atomic_thread_fence(std::memory_order_release);
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SharedInstance.store(tmp, std::memory_order_relaxed);
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}
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}
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return *tmp;
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}
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};
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template <class T>
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std::atomic<T*> SafeSingleton<T>::SharedInstance;
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template <class T>
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std::mutex SafeSingleton<T>::mMutex;
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#endif
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