103 lines
2.6 KiB
C++
103 lines
2.6 KiB
C++
/***
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Copyright (C) 2021 J Reece Wilson (a/k/a "Reece"). All rights reserved.
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File: AuConditionEx.cpp
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Date: 2021-6-12
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Author: Reece
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***/
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#include <Source/RuntimeInternal.hpp>
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#include "AuConditionEx.hpp"
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#include "AuMutex.Generic.hpp"
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#include "AuSemaphore.Generic.hpp"
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namespace Aurora::Threading::Primitives
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{
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// Implementing Condition Variables with Semaphores, Andrew Birrell, MSFT
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// Subsitute semaphore count = 1 with a spinlock and...
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struct SemaphoreConditionVariableImpl : ConditionEx
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{
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SemaphoreConditionVariableImpl();
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void WaitForSignal(Aurora::Threading::IWaitable *pWaitable) override;
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void WaitForSignal(const AuSPtr<Threading::IWaitable> &pWaitable) override;
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void WaitForSignal() override;
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void Signal() override;
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void Broadcast() override;
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private:
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AuUInt32 waiters_;
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SemaphoreImpl s_, h_;
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MutexImpl x_;
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};
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SemaphoreConditionVariableImpl::SemaphoreConditionVariableImpl() :
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s_(0),
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h_(0)
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{
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}
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void SemaphoreConditionVariableImpl::WaitForSignal(Aurora::Threading::IWaitable *pWaitable)
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{
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return WaitForSignal(AuUnsafeRaiiToShared(pWaitable));
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}
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void SemaphoreConditionVariableImpl::WaitForSignal(const AuSPtr<Threading::IWaitable> &pWaitable)
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{
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this->x_.Lock();
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this->waiters_++;
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this->x_.Unlock();
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if (pWaitable)
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{
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pWaitable->Unlock();
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}
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this->s_.Lock();
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this->h_.Unlock();
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if (pWaitable)
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{
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pWaitable->Lock();
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}
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}
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void SemaphoreConditionVariableImpl::WaitForSignal()
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{
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WaitForSignal(nullptr);
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}
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void SemaphoreConditionVariableImpl::Signal()
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{
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this->x_.Lock();
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if (this->waiters_ > 0)
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{
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this->waiters_--;
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this->s_.Unlock(); // 1 may pass
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this->h_.Lock(); // finish operation - wait for the alive signal back
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}
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this->x_.Unlock();
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}
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void SemaphoreConditionVariableImpl::Broadcast()
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{
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this->x_.Lock();
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this->s_.Unlock(this->waiters_); // all may pass at once
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for (auto i = 0; i < this->waiters_; i++)
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{
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this->h_.Lock(); // finish operation - wait for the alive signal back
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}
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this->waiters_ = 0;
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this->x_.Unlock();
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}
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AUKN_SYM ConditionEx *FeaturefulConditionNew()
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{
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return _new SemaphoreConditionVariableImpl();
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}
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AUKN_SYM void FeaturefulConditionRelease(ConditionEx *pCVEx)
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{
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AuSafeDelete<SemaphoreConditionVariableImpl *>(pCVEx);
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}
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} |