AuroraRuntime/Source/Threading/AuWakeOnAddress.hpp

/***
    Copyright (C) 2023 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: AuWakeOnAddress.hpp
    Date: 2023-3-10
    Author: Reece
***/
#pragma once

#include "Primitives/AuConditionMutex.Generic.hpp"
#include "Primitives/AuConditionVariable.Generic.hpp"

namespace Aurora::Threading /*::Primitives for this file only!*/
{
    static const auto kDefaultWaitPerProcess = 32;

    struct WaitState;

    struct WaitBuffer
    {
        char buffer[8];
        AuUInt8 uSize;

        static WaitBuffer From(const void *pBuf, AuUInt8 uSize);
        bool Compare(const void *pBuf);
        bool Compare(WaitState &state);
    };

    struct WaitState
    {
        WaitBuffer compare;
        AuOptionalEx<AuUInt64> qwNanoseconds;
        AuOptionalEx<AuUInt32> uDownsizeMask;
    };

    struct WaitEntry
    {
        WaitEntry();
        ~WaitEntry();

        // synch
        AuUInt32 uAtomic {}; // fastpath
        Primitives::ConditionMutexImpl mutex; // mutex ctor must come before var
        Primitives::ConditionVariableImpl variable; // ...and something all 2007+ micro and monolithic kernels should have to yield for an event

        // state
        const void *pAddress {};
        AuUInt8 uSize {};

        // bookkeeping (parent container)
        bool bOverflow {};

        bool TryAcquire(const void *pAddress, AuUInt8 uSize);
        void Release();

        bool SleepOn(WaitState &state);
        bool TryWake(const void *pAddress);
        bool TryWakeNoLock(const void *pAddress);
        bool TryWakeNoLockNoReallyNoLock(const void *pAddress);
    };

    struct ProcessWaitContainer
    {
        AuUInt32 uAtomic {};
        WaitEntry entries[kDefaultWaitPerProcess];
        AuList<AuSPtr<WaitEntry>> overflow;

        AuSPtr<WaitEntry> WaitBufferFrom(void *pAddress, AuUInt8 uSize);

        template <typename T>
        bool IterateAll(T callback);

        template <typename T>
        bool IterateForceNoCreateDuringOp(T callback);

        void Lock();

        void Unlock();

        void Remove(WaitEntry *pParent);
    };
}