AuroraRuntime/Source/Threading/Primitives/AuMutex.NT.cpp

/***
    Copyright (C) 2021 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: AuMutex.NT.cpp
    Date: 2021-6-12
    Author: Reece
***/
#include <Source/RuntimeInternal.hpp>
#include "AuMutex.Generic.hpp"
#include "SMPYield.hpp"

#if !defined(_AURUNTIME_GENERICMUTEX)
#include "AuMutex.NT.hpp"
#include "AuConditionMutex.NT.hpp"
#include <Time/Time.hpp>

#if !defined(NTSTATUS_TIMEOUT)
    #define NTSTATUS_TIMEOUT 0x102
#endif

namespace Aurora::Threading::Primitives
{
    Mutex::Mutex()
    {
        if (!pWaitOnAddress)
        {
        #if 0
            ::InitializeSRWLock(&this->atomicHolder_);
            ::InitializeConditionVariable(&this->wakeup_);
        #endif
        }
        this->state_ = 0;
    }

    Mutex::~Mutex()
    {

    }

    bool Mutex::HasOSHandle(AuMach &mach)
    {
        return false;
    }

    bool Mutex::TryLock()
    {
        return DoTryIf([=]()
        {
            return ::_interlockedbittestandset((volatile LONG *)&this->state_, 0) == 0;
        });
    }

    bool Mutex::HasLockImplementation()
    {
        return true;
    }

    void Mutex::Lock()
    {
        auto status = Lock(0);
        SysAssert(status, "Couldn't lock Mutex object");
    }

    bool Mutex::Lock(AuUInt64 uTimeout)
    {
        return LockNS(AuMSToNS<AuUInt64>(uTimeout));
    }

    bool Mutex::LockNS(AuUInt64 uTimeout)
    {
        bool returnValue = false;

        if (TryLock())
        {
            return true;
        }

        AuUInt64 uStartTime = Time::SteadyClockNS();
        AuUInt64 uEndTime   = uStartTime + uTimeout;

        if (pWaitOnAddress)
        {
            auto state = this->state_;
            while (::_interlockedbittestandset((volatile LONG *)&this->state_, 0) != 0)
            {
                AuUInt32 uTimeoutMS = INFINITE;

                if (uTimeout != 0)
                {
                    uStartTime = Time::SteadyClockNS();
                    if (uStartTime >= uEndTime)
                    {
                        return false;
                    }

                    uTimeoutMS = AuNSToMS<AuInt64>(uEndTime - uStartTime);
                }

                if (!uTimeoutMS)
                {
                    SMPPause();
                    AuThreading::ContextYield();
                }
                else
                {
                    (void)pWaitOnAddress(&this->state_, &state, sizeof(this->state_), uTimeoutMS);
                }

                state = this->state_;
            }

            return true;
        }
        else
        {
        #if 0
            ::AcquireSRWLockShared(&this->atomicHolder_);

            BOOL status = false;
            while (!this->TryLock())
            {
                AuUInt32 uTimeoutMS = INFINITE;

                if (uTimeout != 0)
                {
                    uStartTime = Time::SteadyClockNS();
                    if (uStartTime >= uEndTime)
                    {
                        goto exitWin32;
                    }

                    uTimeoutMS = AuNSToMS<AuInt64>(uEndTime - uStartTime);
                }

                if (!uTimeoutMS)
                {
                    ::ReleaseSRWLockShared(&this->atomicHolder_);
                    SMPPause();
                    AuThreading::ContextYield();
                    ::AcquireSRWLockShared(&this->atomicHolder_);
                }
                else
                {
                    (void)SleepConditionVariableSRW(&this->wakeup_, &this->atomicHolder_, uTimeoutMS, CONDITION_VARIABLE_LOCKMODE_SHARED);
                }
            }

            returnValue = true;

        exitWin32:
            ::ReleaseSRWLockShared(&this->atomicHolder_);
        #else

            if (!uTimeout)
            {
                while (!TryLock())
                {
                    auto &uValueRef = this->state_;
                    auto uValue = uValueRef | 1;

                    if (AuAtomicCompareExchange(&uValueRef, uValue + FAST_M_WAIT, uValue) == uValue)
                    {
                        pNtWaitForKeyedEvent(gKeyedEventHandle, (void *)&uValueRef, 0, NULL);

                        AuAtomicSub(&uValueRef, FAST_M_WAIT);
                    }
                }

                return true;
            }
            else
            {
                auto &uValueRef = this->state_;
                returnValue = true;

                auto uEndTimeSteady = AuTime::SteadyClockNS()  + uTimeout;
                auto uEndTimeWall   = AuTime::CurrentClockNS() + uTimeout;

                while (!TryLock())
                {
                    auto uValue = uValueRef | 1;

                    if (AuTime::SteadyClockNS() >= uEndTimeSteady)
                    {
                        returnValue = TryLock();
                        break;
                    }

                    if (AuAtomicCompareExchange(&uValueRef, uValue + FAST_M_WAIT, uValue) == uValue)
                    {
                        auto uTargetTimeNt  = AuTime::ConvertTimestampNs(uEndTimeWall);

                        LARGE_INTEGER word;
                        word.QuadPart = uTargetTimeNt;

                        auto uStatus = pNtWaitForKeyedEvent(gKeyedEventHandle, (void *)&this->state_, 0, &word);
                        AuAtomicSub(&uValueRef, FAST_M_WAIT);

                        if (uStatus == NTSTATUS_TIMEOUT)
                        {
                            // i suspect we're bailing out too fast
                            //returnValue = false;
                        }
                        else
                        {
                            SysAssertDbg(uStatus == 0);
                        }
                    }
                }
            }

        #endif
            return returnValue;
        }
    }

    void Mutex::Unlock()
    {
        if (!pWaitOnAddress)
        {
        #if 0
            ::AcquireSRWLockExclusive(&this->atomicHolder_);
            this->state_ = 0;
            ::ReleaseSRWLockExclusive(&this->atomicHolder_);
            ::WakeAllConditionVariable(&this->wakeup_);
        #else

            auto &uValueRef = this->state_;
            auto uValue = uValueRef;

            if (uValue == 1)
            {
                if (AuAtomicCompareExchange(&uValueRef, 0u, 1u) == 1u)
                {
                    return;
                }
            }

            while (true)
            {
                if (uValue < FAST_M_WAIT)
                {
                    return;
                }

                if (uValue & 1)
                {
                    return;
                }

                if (uValue & FAST_M_WAKE)
                {
                    return;
                }

                if (AuAtomicCompareExchange(&uValueRef, uValue - FAST_M_WAIT + FAST_M_WAKE, uValue) == uValue)
                {
                    pNtReleaseKeyedEvent(gKeyedEventHandle, (void *)&uValueRef, 0, NULL);
                    return;
                }

                SMPPause();
            }

        #endif
        }
        else
        {
            this->state_ = 0;
            pWakeByAddressSingle((void *)&this->state_);
        }
    }
    
    AUKN_SYM IWaitable *MutexNew()
    {
        return _new Mutex();
    }

    AUKN_SYM void MutexRelease(IWaitable *pMutex)
    {
        AuSafeDelete<Mutex *>(pMutex);
    }
}

#endif