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

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

    File: AuMutex.Win32.cpp
    Date: 2021-6-12
    Author: Reece
***/
#include <Source/RuntimeInternal.hpp>
#include "AuMutex.Generic.hpp"

#if !defined(_AURUNTIME_GENERICMUTEX)
#include "AuMutex.NT.hpp"

namespace Aurora::Threading::Primitives
{
    Mutex::Mutex()
    {
        InitializeSRWLock(&atomicHolder_);
        InitializeConditionVariable(&wakeup_);
        state_ = 0;
    }

    Mutex::~Mutex()
    {

    }

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

    bool Mutex::TryLock()
    {
        return _interlockedbittestandset(&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 timeout)
    {
        bool returnValue = false;

        AcquireSRWLockShared(&atomicHolder_);

        AuInt64 startTime = Time::CurrentClockMS();
        AuInt64 endTime   = startTime + timeout;

        BOOL status = false;
        while (!TryLock())
        {
            AuUInt32 timeoutMs = INFINITE;

            if (timeout != 0)
            {
                startTime = Time::CurrentClockMS();
                if (startTime >= endTime)
                {
                    goto exitWin32;
                }

                timeoutMs = endTime - startTime;
            }

            status = SleepConditionVariableSRW(&wakeup_, &atomicHolder_, timeoutMs, CONDITION_VARIABLE_LOCKMODE_SHARED);
            if (!status)
            {
                SysAssertExp(GetLastError() == ERROR_TIMEOUT);
                goto exitWin32;
            }
        }

        returnValue = true;

    exitWin32:
        ReleaseSRWLockShared(&atomicHolder_);
        return returnValue;
    }

    void Mutex::Unlock()
    {
        AcquireSRWLockExclusive(&atomicHolder_);
        state_ = 0;
        ReleaseSRWLockExclusive(&atomicHolder_);
        WakeAllConditionVariable(&wakeup_);
    }
    
    AUKN_SYM IWaitable *MutexNew()
    {
        return _new Mutex();
    }

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

#endif