AuroraRuntime/Include/Aurora/Threading/LockGuardTry.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<typename T>
    class TryLockGuard
    {
    private:
        using Internal_t = std::remove_pointer_t<T>;
        bool bLockSuccessful;
        
    public:

        TryLockGuard(T &lock) 
        {
            if constexpr (std::is_pointer_v<T>)
            {
                annoying_ = lock;
            }
            else
            {
                annoying_ = &lock;
            }

            if constexpr (AuIsBaseOfTemplate<AURORA_RUNTIME_AU_SHARED_PTR, Internal_t>::value || AuIsBaseOfTemplate<AURORA_RUNTIME_AU_UNIQUE_PTR, Internal_t>::value)
            {
                bLockSuccessful = annoying_->get()->TryLock();
            }
            else
            {
                bLockSuccessful = annoying_->TryLock();
            }
        }

        TryLockGuard(T &&lock) 
        {
            if constexpr (std::is_pointer_v<T>)
            {
                annoying_ = lock;
            }
            else
            {
                annoying_ = &lock;
            }

            if constexpr (AuIsBaseOfTemplate<AURORA_RUNTIME_AU_SHARED_PTR, Internal_t>::value || AuIsBaseOfTemplate<AURORA_RUNTIME_AU_UNIQUE_PTR, Internal_t>::value)
            {
                bLockSuccessful = annoying_->get()->TryLock();
            }
            else
            {
                bLockSuccessful = annoying_->TryLock();
            }
        }
        
        ~TryLockGuard()
        {
            if (!bLockSuccessful)
            {
                return;
            }

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

        const bool Locked() const
        {
            return bLockSuccessful;
        }
    private:
        std::conditional_t<std::is_pointer_v<T>, T, T*> annoying_;
    };
    
    #define AU_TRY_LOCK_GUARD(variable) Aurora::Threading::TryLockGuard<decltype(variable)>  AU_CONCAT(__stack_lock, __COUNTER__) (variable);
    #define AU_TRY_LOCK_GUARD_RET_(variable, value, counter) Aurora::Threading::TryLockGuard<decltype(variable)> AU_CONCAT(__stack_lock, counter) (variable); if (!(AU_CONCAT(__stack_lock, counter).Locked())) return value;
    #define AU_TRY_LOCK_GUARD_RET_VAL(variable, value) AU_TRY_LOCK_GUARD_RET_(variable, value, AU_WHAT(__COUNTER__))
    #define AU_TRY_LOCK_GUARD_RET_DEF(variable) AU_TRY_LOCK_GUARD_RET_VAL(variable, {})
    #define AU_TRY_LOCK_GUARD_RET(variable) AU_TRY_LOCK_GUARD_RET_VAL(variable, )
}