ScopeTryLock.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreTypes.h"
#include "Misc/AssertionMacros.h"
#include "Misc/NotNull.h"
#include "HAL/CriticalSection.h"
 
namespace UE
{
    template <typename MutexType>
    class TScopeTryLock
    {
    public:
        [[nodiscard]] explicit TScopeTryLock(MutexType& InMutex)
        {
            if (InMutex.TryLock())
            {
                HeldMutex = &InMutex;
            }
        }
 
        ~TScopeTryLock()
        {
            if (HeldMutex)
            {
                HeldMutex->Unlock();
            }
        }
 
        UE_FORCEINLINE_HINT bool IsLocked()
        {
            return HeldMutex != nullptr;
        }
 
    private:
        TScopeTryLock(const TScopeTryLock&) = delete;
        TScopeTryLock& operator=(TScopeTryLock&) = delete;
 
        MutexType* HeldMutex = nullptr;
    };
}
 
class FScopeTryLock : private UE::TScopeTryLock<FCriticalSection>
{
public:
    // Constructor that tries to lock the critical section.
    [[nodiscard]] explicit FScopeTryLock(TNotNull<FCriticalSection*> InCriticalSection) : UE::TScopeTryLock<FCriticalSection>(*InCriticalSection)
    {
    }
 
    // You must call IsLocked to test that the lock was acquired.
    using UE::TScopeTryLock<FCriticalSection>::IsLocked;
};