AuroraRuntime/Include/Aurora/Threading/LockGuard.hpp

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

    File: LockGuard.hpp
    Date: 2021-6-10
    Author: Reece
***/
#pragma once

namespace Aurora::Threading
{

    template <class T>
    struct AuOperatorArrow
    {
        template <class C> static constexpr AuTrueType  Test(decltype(&C::operator->));
        template <class C> static constexpr AuFalseType Test(...);
        using type = decltype(Test<const T>(0));
    };

    template<typename T>
    class LockGuard
    {
        using Constless_t = T;
        using ConstlessPtr_t = AuConditional_t<AuIsPointer_v<Constless_t>, Constless_t, Constless_t *>;
        using Internal_t = AuRemovePointer_t<Constless_t>;

        static const bool kBoolArrowOp = AuOperatorArrow<AuRemovePointer_t<T>>::type::value;

    public:
        
        LockGuard(const T &lock)
        {
            ConstlessPtr_t pInterface {};
            if constexpr (AuIsPointer_v<T>)
            {
                pInterface = (ConstlessPtr_t)lock;
            }
            else
            {
                pInterface = (ConstlessPtr_t)&lock;
            }

            if constexpr (AuIsBaseOfTemplate<AURORA_RUNTIME_AU_SHARED_PTR, Internal_t>::value || AuIsBaseOfTemplate<AURORA_RUNTIME_AU_UNIQUE_PTR, Internal_t>::value)
            {
                pInterface->get()->Lock();
            }
            else if constexpr (kBoolArrowOp)
            {
                (*pInterface)->Lock();
            }
            else
            {
                pInterface->Lock();
            }

            this->pAnnoying_ = pInterface;
        }

        ~LockGuard()
        {
            if (!this->pAnnoying_)
            {
                return;
            }

            if constexpr (AuIsBaseOfTemplate<AURORA_RUNTIME_AU_SHARED_PTR, Internal_t>::value || AuIsBaseOfTemplate<AURORA_RUNTIME_AU_UNIQUE_PTR, Internal_t>::value)
            {
                this->pAnnoying_->get()->Unlock();
            }
            else if constexpr (kBoolArrowOp)
            {
                (*this->pAnnoying_)->Unlock();
            }
            else
            {
                this->pAnnoying_->Unlock();
            }
        }

    private:
        ConstlessPtr_t pAnnoying_ {};
    };
    
    #define AU_LOCK_GUARD(variable) Aurora::Threading::LockGuard<decltype(variable)>  AU_CONCAT(__stack_lock, __COUNTER__) (variable);
}