AuroraRuntime/Source/IO/Loop/Loop.cpp

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

    File: Loop.cpp
    Date: 2021-9-21
    Author: Reece
***/
#include <Source/RuntimeInternal.hpp>
#include "Loop.hpp"
#include "ILoopSourceEx.hpp"
#include "LSIOHandle.hpp"
#include "LSTimerNoKernelScheduler.hpp"
#include <Source/Threading/Primitives/SMTYield.hpp>

namespace Aurora::IO::Loop
{
    // Write guards the transition period just after ::select-like and during { {onTriggered(...); } { reset spurious } }
    // By read-locking, depending on the platform, you provide some insurance that WaitMultipleLoopSources didn't
    // temporarily lock the resource. Under POSIX, this RWLock is fully respected. Under the platform agnostic path,
    // it is only partially respected. Under Win32, it's not really respected, but these issues can be worked around,
    // by using the interop-ready loop sources; under win32s fast path, interop-ready loop sources can be atomically 
    // AND locked via the native nt mechanism. 
    AuRWRenterableLock gWaitForMultipleALLLock;

    bool WaitMultipleAndOldImpl(const AuList<AuSPtr<Loop::ILoopSource>> &lsList,
                                AuList<AuSPtr<Loop::ILoopSource>> &signaled,
                                AuUInt64 uFlags,
                                AuOptional<AuUInt32> optTimeoutMS,
                                bool bSpin,
                                bool bHasTimeOut,
                                bool bSleepForever,
                                bool bZeroTick,
                                AuUInt64 uTimeoutEnd,
                                bool bAvoidKrn,
                                AuUInt32 uBaseFlags);

    bool WaitMultipleAndNewImpl(const AuList<AuSPtr<Loop::ILoopSource>> &lsList,
                                AuList<AuSPtr<Loop::ILoopSource>> &signaled,
                                AuUInt64 uFlags,
                                AuOptional<AuUInt32> optTimeoutMS,
                                bool bSpin,
                                bool bHasTimeOut,
                                bool bSleepForever,
                                bool bZeroTick,
                                AuUInt64 uTimeoutEnd,
                                bool bAlert,
                                bool bBreakAPCs);

#if !defined(AURORA_IS_MODERNNT_DERIVED)
    AUKN_SYM AuSPtr<ILoopSource>    NewLSWin32Source(bool)
    {
        return {};
    }
#endif

#if !defined(AURORA_IS_XNU_DERIVED)
    AUKN_SYM AuSPtr<ILoopSource>    NewLSAppleSource()
    {
        return {};
    }
#endif

    AUKN_SYM AuSPtr<ILoopSource>    NewLSFile(const AuSPtr<AuIO::IAsyncTransaction> &pFileTransaction)
    {
        if (!pFileTransaction)
        {
            SysPushErrorArg();
            return {};
        }

        return pFileTransaction->NewLoopSource();
    }

    AUKN_SYM AuSPtr<ILoopSource>    NewStdIn()
    {
        return AuConsole::StdInBufferLoopSource();
    }

    AUKN_SYM AuSPtr<ILoopSource>    NewLSAsync(AuAsync::WorkerPId_t workerPid)
    {
        if (!workerPid)
        {
            return AuAsync::GetAsyncApp()->WorkerToLoopSource(workerPid);
        }

        return workerPid.GetPool()->WorkerToLoopSource(workerPid);
    }

#if defined(AURORA_IS_MODERNNT_DERIVED) || defined(AURORA_IS_POSIX_DERIVED)
    AuList<AuSPtr<ILoopSource>> WaitMultipleOrObjects(const AuList<AuSPtr<ILoopSource>> &objects, bool bAlert, bool bBreakAPCs, bool bZeroTick, AuUInt32 timeout, bool bAllowOthers, bool &bTooMany);
    bool WaitMultipleAndObjects(const AuList<AuSPtr<ILoopSource>> &objects, bool bAlert, bool bBreakAPCs, bool bZeroTick, AuUInt64 qwTimeoutAbs, bool &bTooMany, bool &bTimeout);
#endif
    AuList<AuSPtr<ILoopSource>> WaitMultipleOrObjectsFallback(const AuList<AuSPtr<ILoopSource>> &objects, AuUInt32 timeout, bool bAlert, bool bBreak, bool bZeroTick, bool bAllowOthers, bool &bTimeout);

    void ResetLoopSourceFalseAlarm(const AuSPtr<Loop::ILoopSource> &pLoopSource)
    {
        if (!pLoopSource)
        {
            return;
        }

        if (pLoopSource->GetType() == ELoopSource::eSourceWin32)
        {
            return;
        }

        if (auto pSemaphore = AuDynamicCast<Loop::LSTimerIP>(pLoopSource))
        {
            // TOOD:Hack:
            AU_LOCK_GUARD(pSemaphore->cs);
            if (pSemaphore->maxIterationsOrZero_)
            {
                AuAtomicSub(&pSemaphore->count_, 1u);
            }

            pSemaphore->UpdateTimeSteadyNs(pSemaphore->targetTime_ - pSemaphore->reschedStepNsOrZero_);
            pSemaphore->Set();
            return;
        }

        if (auto pMutex = AuDynamicCast<Loop::ILSMutex>(pLoopSource))
        {
            pMutex->Unlock();
            return;
        }

        if (auto pEvent = AuDynamicCast<Loop::ILSEvent>(pLoopSource))
        {
            pEvent->Set();
            return;
        }

        if (auto pSemaphore = AuDynamicCast<Loop::ILSSemaphore>(pLoopSource))
        {
            pSemaphore->AddOne();
            return;
        }
    }

    AUKN_SYM bool WaitMultipleLoopSources(const AuList<AuSPtr<Loop::ILoopSource>> &lsList,
                                          AuList<AuSPtr<Loop::ILoopSource>> &signaled,
                                          bool bAny,
                                          AuOptionalEx<AuUInt32> optTimeoutMS)
    {
        return WaitMultipleLoopSourcesEx(lsList, signaled, bAny ? kWaitMultipleFlagAny : 0, optTimeoutMS);
    }

    AUKN_SYM bool WaitMultipleLoopSourcesEx(const AuList<AuSPtr<Loop::ILoopSource>> &lsList,
                                            AuList<AuSPtr<Loop::ILoopSource>> &signaled,
                                            AuUInt64 uFlags,
                                            AuOptional<AuUInt32> optTimeoutMS)
    {
        signaled.clear();
        
        bool bAny          { bool(uFlags & kWaitMultipleFlagAny) };
        bool bSpin         { !(uFlags & kWaitMultipleFlagNoSpin) };
        bool bAvoidKrn     { bool(uFlags & kWaitMultipleFlagAvoidKern) };
        bool bZeroTick     { optTimeoutMS && optTimeoutMS.Value() == 0 };
        bool bHasTimeOut   { optTimeoutMS && optTimeoutMS.Value() };
        bool bBreakAPCs    { bool(uFlags & kWaitMultipleFlagBreakAfterAPC) };
        bool bNoAlert      { bool(uFlags & kWaitMultipleFlagNoIOCallbacks) };
        bool bAlert        { !bNoAlert };
        bool bSleepForever { !optTimeoutMS };
        AuUInt32 uBaseFlags {};

        if (lsList.empty())
        {
            if (bNoAlert)
            {
                return true;
            }
            else
            {
                if (bZeroTick)
                {
                    return IOYield();
                }
                else if (bHasTimeOut)
                {
                    return IOYieldFor(optTimeoutMS.Value());
                }
                else
                {
                    return IOYieldFor(0);
                }
            }
        }

        if (bNoAlert)
        {
            uBaseFlags |= kFlagLSTryNoIOAlerts;
        }

        if (lsList.size() == 1)
        {
            AuUInt8 uFlags {};
            auto pSource = lsList[0];
            if (!pSource)
            {
                signaled.push_back({});
                return true;
            }

            if (!bSpin)
            {
                uFlags = kFlagLSTryNoSpin;
            }

            uFlags |= uBaseFlags;

            bool bStatus {};
            if (bSleepForever)
            {
                bStatus = pSource->WaitOnExt(uFlags, 0);
            }
            else if (bHasTimeOut)
            {
                bStatus = pSource->WaitOnExt(uFlags, optTimeoutMS.value());
            }
            else
            {
                bStatus = pSource->IsSignaledExt(uFlags);
            }

            if (bStatus)
            {
                signaled.push_back(pSource);
            }

            return bStatus;
        }

        AuUInt64 uTimeoutEnd = bHasTimeOut ?
            AuTime::SteadyClockNS() + AuMSToNS<AuUInt64>(optTimeoutMS.value()) :
            0;

        AU_DEBUG_MEMCRUNCH;

        signaled.reserve(lsList.size());

        if (!bAny)
        {
            // try to sleep somewhat atomically.
            // under windows, this isn't quite possible with in process primitives. we just have to hope for interop-ready + kernel fast path.
            // under linux, it's fine, because we can select or poll, and then { lock { ... } }
            if (gRuntimeConfig.ioConfig.bUseSelectWaitAllStrat)
            {
                bool bTooMany {};
                bool bTimeout {};
                bool bRet = 
                    WaitMultipleAndObjects(lsList, bAlert, bBreakAPCs, false, uTimeoutEnd, bTooMany, bTimeout);

                if (!bTooMany)
                {
                    if (bRet)
                    {
                        // explicit everyone became alert via select-like and said OK to our vtable query
                        signaled = lsList;
                        return true;
                    }
                    else if (bTimeout)
                    {
                        // explicit timeout timestamp exceeded
                        return false;
                    }
                    else
                    {
                        // Win32 message loop needs tending to or APC dispatch
                        return true;
                    }
                }
            }

            // try to sleep on one item in the list, and then atomically acquire the rest if that one succeeded.
            // it can be observed that a single item in this lsList dips to non-signaled momentarily.
            // the same may also happen with local (not native) win32 loop sources under WaitMultipleAndObjects.
            // (interop ready/win32/win32-fast path is safe)
            // (local or interop/linux/posix-fast path is safe)
            // (local/win32 technically breaks WaitForMultipleObject docs)
            // (any/win32/>64 handles generic path technically breaks WaitForMultipleObject docs)
            // (any/*/generic path technically breaks WaitForMultipleObject docs)
            // our implementation is good enough to work on real world code, but it technically can break some multi-mutex wait and multi-consumer event-happened queries code.
            if (gRuntimeConfig.ioConfig.bUseOldIOWaitAllAlg)
            {
                return WaitMultipleAndOldImpl(lsList, signaled, uFlags, optTimeoutMS, bSpin, bHasTimeOut, bSleepForever, bZeroTick, uTimeoutEnd, bAvoidKrn, uBaseFlags);
            }
            else
            {
                return WaitMultipleAndNewImpl(lsList, signaled, uFlags, optTimeoutMS, bSpin, bHasTimeOut, bSleepForever, bZeroTick, uTimeoutEnd, bAlert, bBreakAPCs);
            }        
        }
        else
        {
            bool bTimedout {};
            AuList<AuSPtr<Loop::ILoopSource>> signalTemp;

            auto lsList2 = lsList;
            bool bAnyFound {};

            auto DoTheThing = [&](bool bLastTick)
            {
                for (auto itr = lsList2.begin();
                     itr != lsList2.end();
                     )
                {
                    if (signalTemp.size() &&
                        uFlags & kWaitMultipleFlagBreakAfterOne)
                    {
                        break;
                    }

                    auto pSource = *itr;
                    if (!pSource)
                    {
                        signalTemp.push_back({});
                        itr = lsList2.erase(itr);
                        continue;
                    }

                    auto eType = pSource->GetType();

                    if (eType == ELoopSource::eSourceFastMutex ||
                        eType == ELoopSource::eSourceFastSemaphore ||
                        eType == ELoopSource::eSourceFastEvent)
                    {
                        bAnyFound = true;

                        if (pSource->IsSignaledExt(uBaseFlags | kFlagLSTryNoSpin))
                        {
                            signalTemp.push_back(pSource);
                            itr = lsList2.erase(itr);
                        }
                        else
                        {
                            if (bLastTick && bZeroTick)
                            {
                                itr = lsList2.erase(itr);
                            }
                            else
                            {
                                itr++;
                            }
                        }
                    }
                    else
                    {
                        itr++;
                    }
                }
            };

            if (bSpin &&
                gRuntimeConfig.threadingConfig.bPlatformIsSMPProcessorOptimized &&
                !bZeroTick)
            {
                AuThreadPrimitives::DoTryIf([&]()
                {
                    DoTheThing(false);

                    if (!bAnyFound)
                    {
                        return true;
                    }

                    return bool(signalTemp.size());
                });

                if (bAnyFound)
                {
                    DoTheThing(true);
                }
            }
            else
            {
                DoTheThing(true);
            }

            bool bAllowOthers = !(uFlags & kWaitMultipleFlagBreakAfterOne);

            if (lsList2.size() &&
                (bAllowOthers || signalTemp.empty()))
            {
                bZeroTick |= bool(signalTemp.size());
                AuUInt32 uTimeoutMS {};
                bool bTooMany {};

                do
                {
                    if (uTimeoutEnd)
                    {
                        auto uStartTime = Time::SteadyClockNS();
                        if (uStartTime >= uTimeoutEnd)
                        {
                            bZeroTick = true;
                        }

                        uTimeoutMS = AuNSToMS<AuInt64>(uTimeoutEnd - uStartTime);
                        if (!uTimeoutMS)
                        {
                            bZeroTick = true;
                        }
                    }

                #if defined(AURORA_IS_MODERNNT_DERIVED)
                    if (AuBuild::kCurrentVendor == AuBuild::EVendor::eGenericMicrosoft &&
                        lsList2.size() < MAXIMUM_WAIT_OBJECTS)
                    {
                        signaled = WaitMultipleOrObjects(lsList2, bAlert, bBreakAPCs, bZeroTick, uTimeoutMS, bAllowOthers, bTooMany);
                        bTimedout = uTimeoutEnd && uTimeoutMS && !bZeroTick ?
                            Time::SteadyClockNS() >= uTimeoutEnd :
                            false;
                    }
                    else
                #elif defined(AURORA_IS_POSIX_DERIVED)
                    if (true)
                    {
                        signaled = WaitMultipleOrObjects(lsList2, bAlert, bBreakAPCs,bZeroTick, uTimeoutMS, bAllowOthers, bTooMany);
                        bTimedout = uTimeoutEnd && uTimeoutMS && !bZeroTick ?
                            Time::SteadyClockNS() >= uTimeoutEnd :
                            false;
                    }
                    else
                #endif
                    {
                        bTooMany = true;
                    }
                }
                while (!bTimedout && !bTooMany && !bZeroTick && signaled.empty() && (!bBreakAPCs || bNoAlert));

                if (bTooMany)
                {
                    signaled = WaitMultipleOrObjectsFallback(lsList2, uTimeoutMS, bAlert, bBreakAPCs, bZeroTick, bAllowOthers, bTimedout);
                    bTimedout &= !bZeroTick;
                }
            }

            signaled.insert(signaled.end(), signalTemp.begin(), signalTemp.end());

            if (bTimedout)
            {
                return false;
            }
            else if (bBreakAPCs && bAlert)
            {
                return true;
            }
            else
            {
                return signaled.size();
            }
        }

        return false;
    }

    bool WaitMultipleAndNewImpl(const AuList<AuSPtr<Loop::ILoopSource>> &lsList,
                                AuList<AuSPtr<Loop::ILoopSource>> &signaled,
                                AuUInt64 uBaseFlags,
                                AuOptional<AuUInt32> optTimeoutMS,
                                bool bSpin,
                                bool bHasTimeOut,
                                bool bSleepForever,
                                bool bZeroTick,
                                AuUInt64 uTimeoutEnd,
                                bool bAlert,
                                bool bBreakAPCs)
    {
        AuUInt32 uTick {};

        while (true)
        {
            AuUInt32 uChecked {};
            bool bStatus {};

            // Sleep on one (warn: this one primitive will appear to be non-signaled until we can write-acquire gWaitForMultipleALLLock)
            //              (... : select, poll, etc based paths do not have this issue!)
            {
                bool bIsMutex {};
                ELoopSource eType;
                AuUInt8 uFlags {};

                if (!bSpin)
                {
                    uFlags |= kFlagLSTryNoSpin;
                }

                if (!bAlert)
                {
                    uFlags |= kFlagLSTryNoIOAlerts;
                }

                auto a = (uTick / lsList.size()) % 2;
                uChecked = uTick++ % lsList.size();
                auto pCurrent = lsList[uChecked];
                AuUInt32 uLocalCounter {};
                while (!pCurrent)
                {
                    uChecked = uTick++ % lsList.size();
                    pCurrent = lsList[pCurrent];
                    if ((uLocalCounter ++) > lsList.size())
                    {
                        return false;
                    }
                }

                eType = pCurrent->GetType();

                bIsMutex = eType == ELoopSource::eSourceMutex ||
                    eType == ELoopSource::eSourceFastMutex;

                if (bIsMutex ^ bool(a))
                {
                    continue;
                }

                if (bHasTimeOut || bSleepForever)
                {
                    bStatus = pCurrent->WaitOnAbsExt(uFlags, uTimeoutEnd);

                    if (!bStatus)
                    {
                        if (uTimeoutEnd && AuNSToMS<AuUInt64>(uTimeoutEnd) <= AuTime::SteadyClockMS())
                        {
                            return false;
                        }
                        else if (bAlert && bBreakAPCs)
                        {
                            return true;
                        }
                    }
                }
                else
                {
                    bStatus = pCurrent->IsSignaledExt(uFlags | kFlagLSTryNoIOAlerts);
                    if (!bStatus && bAlert)
                    {
                        if (IOYield())
                        {
                            return true;
                        }
                    }
                }

                if (bIsMutex)
                {
                    //uTick = 0;
                }
            }

            if (bStatus)
            {
                // Warning: this does not protect the first acquisition !
                AU_LOCK_GLOBAL_GUARD(gWaitForMultipleALLLock->AsWritable());
                AuUInt32 uBreakA {};
                AuUInt32 uBreakIndex {};

                {
                    for (AU_ITERATE_N(a, 2))
                    {
                        bool dBreak {};

                        for (AU_ITERATE_N(i, lsList.size()))
                        {
                            bool bIsMutex {};
                            ELoopSource eType;

                            if (i == uChecked)
                            {
                                continue;
                            }

                            auto &pCurrent = lsList[i];

                            if (!pCurrent)
                            {
                                continue;
                            }

                            eType = pCurrent->GetType();
                            bIsMutex = eType == ELoopSource::eSourceMutex ||
                                eType == ELoopSource::eSourceFastMutex;

                            if (bIsMutex ^ bool(a))
                            {
                                continue;
                            }
                            
                            if (!pCurrent->IsSignaledExt(kFlagLSTryNoSpin | kFlagLSTryNoIOAlerts))
                            {
                                dBreak = true;
                                uBreakIndex = i;
                                break;
                            }
                        }

                        if (dBreak)
                        {
                            uBreakA = a + 1;
                            bStatus = false;
                            break;
                        }
                    }
                }

                if (!bStatus)
                {
                    for (AU_ITERATE_N(a, uBreakA))
                    {
                        for (AU_ITERATE_N(i, uBreakIndex))
                        {
                            auto &pCurrent = lsList[i];
                            bool bIsMutex {};
                            ELoopSource eType;

                            if (!pCurrent)
                            {
                                continue;
                            }

                            if (i == uChecked)
                            {
                                continue;
                            }

                            eType = pCurrent->GetType();
                            bIsMutex = eType == ELoopSource::eSourceMutex ||
                                eType == ELoopSource::eSourceFastMutex;

                            if (bIsMutex ^ bool(a))
                            {
                                continue;
                            }

                            ResetLoopSourceFalseAlarm(pCurrent);
                        }
                    }

                    if (auto pSource = lsList[uChecked])
                    {
                        ResetLoopSourceFalseAlarm(pSource);
                    }

                    if (uTimeoutEnd && uTimeoutEnd <= AuTime::SteadyClockNS())
                    {
                        return false;
                    }
                }
                else
                {
                    signaled = lsList;
                    return true;
                }
            }
        }
    }

    bool WaitMultipleAndOldImpl(const AuList<AuSPtr<Loop::ILoopSource>> &lsList,
                                AuList<AuSPtr<Loop::ILoopSource>> &signaled,
                                AuUInt64 uFlags,
                                AuOptional<AuUInt32> optTimeoutMS,
                                bool bSpin,
                                bool bHasTimeOut,
                                bool bSleepForever,
                                bool bZeroTick,
                                AuUInt64 uTimeoutEnd,
                                bool bAvoidKrn,
                                AuUInt32 uBaseFlags)
    {
        AuList<AuUInt32> reverseList;

        {
            AuUInt32 uStartingOffset { 1 };

            auto &entryZero = lsList[0];

            if (!entryZero)
            {
                signaled.push_back({});
            }

            if (entryZero)
            {
                bool bStatus {};
                auto eType = entryZero->GetType();
                AuUInt8 uFlags {};

                if (!bSpin)
                {
                    uFlags = kFlagLSTryNoSpin;
                }

                uFlags |= uBaseFlags;

                if (eType == ELoopSource::eSourceMutex ||
                    eType == ELoopSource::eSourceFastMutex)
                {
                    bStatus = false;
                    uStartingOffset = 0;
                    goto mainAllSleep;
                }
                else if (bSleepForever)
                {
                    bStatus = entryZero->WaitOnExt(uFlags, 0);
                }
                else if (bHasTimeOut)
                {
                    bStatus = entryZero->WaitOnExt(uFlags, optTimeoutMS.value());
                }
                else
                {
                    bStatus = entryZero->IsSignaledExt(uFlags);
                }
         
                if (!bStatus)
                {
                    goto next;
                }
                else
                {
                    reverseList.push_back(0);
                    signaled.push_back(entryZero);
                    bZeroTick = true;
                }
            }

        mainAllSleep:

            if (lsList.size() > uStartingOffset &&
                (!bAvoidKrn || signaled.empty()))
            {
                for (AU_ITERATE_N(a, 2))
                {
                    bool dBreak {};

                    for (AU_ITERATE_N_TO_X(i, uStartingOffset, lsList.size()))
                    {
                        AuUInt32 uTimeoutMS {};
                        bool bIsMutex {};
                        ELoopSource eType;

                        auto &pCurrent = lsList[i];

                        eType = pCurrent->GetType();
                        bIsMutex = eType == ELoopSource::eSourceMutex ||
                            eType == ELoopSource::eSourceFastMutex;

                        if (bIsMutex ^ bool(a))
                        {
                            continue;
                        }
                        
                        if (uTimeoutEnd && !bZeroTick)
                        {
                            auto uStartTime = Time::SteadyClockNS();
                            if (uStartTime >= uTimeoutEnd)
                            {
                                bZeroTick = true;
                            }

                            uTimeoutMS = AuNSToMS<AuInt64>(uTimeoutEnd - uStartTime);
                            if (!uTimeoutMS)
                            {
                                bZeroTick = true;
                            }
                        }

                        if (bZeroTick)
                        {
                            if (bSpin)
                            {
                                if (!pCurrent->IsSignaledExt(uBaseFlags))
                                {
                                    dBreak = true;
                                    break;
                                }

                                bSpin = false;
                            }
                            else
                            {
                                if (!pCurrent->IsSignaledExt(uBaseFlags | kFlagLSTryNoSpin))
                                {
                                    dBreak = true;
                                    break;
                                }
                            }
                        }
                        else
                        {
                            if (bSpin)
                            {
                                if (!pCurrent->WaitOnAbsExt(uBaseFlags, uTimeoutEnd))
                                {
                                    dBreak = true;
                                    break;
                                }

                                // TBD
                                bSpin = false;
                            }
                            else
                            {
                                if (!pCurrent->WaitOnAbsExt(kFlagLSTryNoSpin | uBaseFlags, uTimeoutEnd))
                                {
                                    dBreak = true;
                                    break;
                                }
                            }
                        }

                        reverseList.push_back(i);
                        signaled.push_back(pCurrent);
                    }

                    if (dBreak || signaled.size() != lsList.size())
                    {
                        break;
                    }
                }
            }

        next:
            bool bReturnStatus { true };

            if (signaled.size() != lsList.size())
            {
                bReturnStatus = false;
                signaled.clear();

                for (const auto &uIndex : reverseList)
                {
                    ResetLoopSourceFalseAlarm(lsList[uIndex]);
                }
            }

            return bReturnStatus;
        }
    }

    AuList<AuSPtr<ILoopSource>> WaitMultipleOrObjectsFallback(const AuList<AuSPtr<ILoopSource>> &objects, AuUInt32 timeout, bool bAlert, bool bBreak, bool bZeroTick, bool bAllowOthers, bool &bTimeout)
    {
        AuList<AuSPtr<ILoopSourceEx>> loopSourceExs;
        AuList<AuSPtr<ILoopSource>> triggered;

        if (objects.empty())
        {
            return {};
        }

        bTimeout  = false;

    #if defined(AURORA_IS_MODERNNT_DERIVED)
        // Optimization / can be ignored / based impl details of NTs LoopQueue
        {
            AuUInt32 uBaseFlags { 0 };

            if (!bAlert)
            {
                uBaseFlags |= kFlagLSTryNoIOAlerts;
            }

            // Check past the first loopqueues chug batch
            for (AU_ITERATE_N_TO_X(i, MAXIMUM_WAIT_OBJECTS - 1, objects.size()))
            {
                if (objects[i]->IsSignaledExt(uBaseFlags))
                {
                    triggered.push_back(objects[i]);
                }
            }

            // If we got something
            if (triggered.size())
            {
                // Check everyone
                for (AU_ITERATE_N_TO_X(i, 0, MAXIMUM_WAIT_OBJECTS - 1))
                {
                    if (objects[i]->IsSignaledExt(uBaseFlags))
                    {
                        triggered.push_back(objects[i]);
                    }
                }

                // and then return
                return triggered;
            }

        // otherwise, we just need to gross chug poll.
        }
    #endif

        auto pQueue = AuLoop::NewLoopQueue();
        if (!pQueue)
        {
            return {};
        }

        pQueue->ConfigureDoIOApcCallbacks(bAlert);
        pQueue->ConfigureBreakAnyAfterAPC(bBreak);

        try
        {
            loopSourceExs.reserve(objects.size());
            triggered.reserve(triggered.size());

            for (const auto &source : objects)
            {
                if (!source)
                {
                    continue;
                }

                if (!pQueue->SourceAdd(source))
                {
                    return {};
                }

                if (source->GetType() == ELoopSource::eSourceWin32)
                {
                    continue;
                }

                if (auto pLoopSourceEx = AuDynamicCast<ILoopSourceEx>(source))
                {
                    if (!AuTryInsert(loopSourceExs, pLoopSourceEx))
                    {
                        return {};
                    }
                }
            }
        }
        catch (...)
        {
            return {};
        }

        auto pListener = AuMakeSharedThrow<AuLoop::ILoopSourceSubscriberFunctional>([&](const AuSPtr<ILoopSource> &source)
        {
            triggered.push_back(source);
            return false;
        });

        if (!pQueue->AddCallback(pListener))
        {
            return {};
        }

        for (const auto &source : loopSourceExs)
        {
            source->OnPresleep();
        }
       
        if (bZeroTick)
        {
            (void)pQueue->PumpNonblocking();
        }
        else
        {
            bTimeout = !pQueue->WaitAny(timeout);
        }

        for (AU_ITERATE_N(i, loopSourceExs.size()))
        {
            auto pLoopSource = loopSourceExs[i];

            if (bAllowOthers || triggered.empty())
            {
                if (std::find(triggered.begin(), triggered.end(), pLoopSource) == triggered.end())
                {
                    auto eType = pLoopSource->GetType();

                    if (eType == ELoopSource::eSourceFastMutex ||
                        eType == ELoopSource::eSourceFastSemaphore ||
                        eType == ELoopSource::eSourceFastEvent)
                    {
                        if (pLoopSource->IsSignaledNoSpinIfUserland())
                        {
                            triggered.push_back(pLoopSource);
                        }
                    }
                }
            }

            pLoopSource->OnFinishSleep();
        }

        if (!bAllowOthers && triggered.size() > 1)
        {
            for (AU_ITERATE_N_TO_X(i, 1, triggered.size()))
            {
                ResetLoopSourceFalseAlarm(triggered[i]);
            }

            return { triggered[0] };
        }
        else
        {
            return triggered;
        }
    }

    AUKN_SYM AuInt64                DbgLoopSourceToReadFd(AuSPtr<ILoopSource> pLoopSource)
    {
        if (!pLoopSource)
        {
            return -1;
        }

        auto pSourceEx = AuDynamicCast<Loop::ILoopSourceEx>(pLoopSource);
        if (!pSourceEx)
        {
            return -1;
        }

        if (!pSourceEx->Singular())
        {
            return -1;
        }

        return pSourceEx->GetHandle();
    }

    AUKN_SYM AuInt64                DbgLoopSourceToWriteFd(AuSPtr<ILoopSource> pLoopSource)
    {
        if (!pLoopSource)
        {
            return -1;
        }

        if (auto pIOHandle = AuDynamicCast<Loop::LSIOHandle>(pLoopSource))
        {
            return pIOHandle->pHandle->GetOSWriteHandleSafe().OrElse([&]()
            {
                return pIOHandle->pHandle->GetOSReadHandleSafe();
            }).ValueOr(AuUInt(-1));
        }

        auto pSourceEx = AuDynamicCast<Loop::ILoopSourceEx>(pLoopSource);
        if (!pSourceEx)
        {
            return -1;
        }

        if (!pSourceEx->Singular())
        {
            return -1;
        }

    #if defined(AURORA_IS_POSIX_DERIVED)
        return pSourceEx->GetWriteHandle();
    #else
        return pSourceEx->GetHandle();
    #endif
    }
}