169 lines
3.4 KiB
C++
169 lines
3.4 KiB
C++
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/***
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Copyright (C) 2023 J Reece Wilson (a/k/a "Reece"). All rights reserved.
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File: LSLocalMutex.cpp
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Date: 2023-10-21
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Author: Reece
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***/
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#include <RuntimeInternal.hpp>
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#include "LSLocalMutex.hpp"
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#include <Source/Threading/Primitives/SMTYield.hpp>
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namespace Aurora::IO::Loop
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{
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static auto const kFutexBitWake = 256u;
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LSLocalMutex::LSLocalMutex()
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{
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}
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LSLocalMutex::~LSLocalMutex()
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{
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}
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bool LSLocalMutex::TryInit()
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{
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if (!LSSemaphore::TryInit(1))
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{
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return false;
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}
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return true;
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}
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bool LSLocalMutex::OnTrigger(AuUInt handle)
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{
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if (AuAtomicLoad(&this->uAtomicWord) & kFutexBitWake)
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{
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AuAtomicSub(&this->uAtomicWord, kFutexBitWake);
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}
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return this->TryTakeNoSpin();
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}
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bool LSLocalMutex::Unlock()
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{
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if (!(AuAtomicLoad(&this->uAtomicWord) & 1))
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{
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return false;
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}
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AuAtomicClearU8Lock(&this->uAtomicWord);
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while (true)
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{
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auto uState = AuAtomicLoad(&this->uAtomicWord);
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if (uState & 1)
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{
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return true;
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}
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if (uState & kFutexBitWake)
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{
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if (AuAtomicCompareExchange(&this->uAtomicWord, uState, uState) == uState)
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{
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return true;
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}
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else
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{
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continue;
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}
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}
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if (AuAtomicCompareExchange(&this->uAtomicWord, uState + kFutexBitWake, uState) == uState)
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{
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LSSemaphore::AddOne();
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return true;
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}
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}
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}
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bool LSLocalMutex::IsSignaled()
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{
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return this->TryTake();
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}
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bool LSLocalMutex::WaitOn(AuUInt32 timeout)
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{
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return this->TryTakeWaitMS(timeout);
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}
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ELoopSource LSLocalMutex::GetType()
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{
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return ELoopSource::eSourceMutex;
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}
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bool LSLocalMutex::TryTakeNoSpin()
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{
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return AuAtomicTestAndSet(&this->uAtomicWord, 0) == 0;
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}
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bool LSLocalMutex::TryTakeSpin()
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{
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return Threading::Primitives::DoTryIf([&]
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{
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return this->TryTakeNoSpin();
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});
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}
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bool LSLocalMutex::TryTake()
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{
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return TryTakeNoSpin();
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}
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bool LSLocalMutex::TryTakeWaitMS(AuUInt32 timeout)
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{
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auto uEndTime = AuTime::SteadyClockMS() + timeout;
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if (this->TryTakeSpin())
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{
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return true;
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}
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while (!this->TryTakeNoSpin())
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{
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if (!timeout)
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{
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if (LSSemaphore::WaitOn(0))
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{
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return true;
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}
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}
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else
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{
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auto uStartTime = Time::SteadyClockNS();
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if (uStartTime >= uEndTime)
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{
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return false;
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}
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if (LSSemaphore::WaitOn(AuNSToMS<AuInt64>(uEndTime - uStartTime)))
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{
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return true;
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}
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}
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}
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return true;
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}
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AUKN_SYM AuSPtr<ILSMutex> NewLSMutex()
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{
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auto pMutex = AuMakeShared<LSLocalMutex>();
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if (!pMutex)
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{
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SysPushErrorGeneric();
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return {};
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}
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if (!pMutex->TryInit())
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{
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SysPushErrorNested();
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return {};
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}
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return pMutex;
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}
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}
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