AsyncFileHandleNull.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "Async/AsyncFileHandle.h"
 
 
class FAsyncReadRequestNull : public IAsyncReadRequest
{
public:
    FAsyncReadRequestNull(FAsyncFileCallBack* InCallback, bool bInSizeRequest)
        : IAsyncReadRequest(InCallback, bInSizeRequest, nullptr /* UserSuppliedMemory */)
    {
        bCanceled = true;
        SetComplete();
    }
 
protected:
    virtual void WaitCompletionImpl(float TimeLimitSeconds) override
    {
    }
 
    virtual void CancelImpl() override
    {
    }
 
    virtual void ReleaseMemoryOwnershipImpl() override
    {
    }
};
 
class FAsyncReadFileHandleNull : public IAsyncReadFileHandle
{
public:
    using IAsyncReadFileHandle::IAsyncReadFileHandle;
 
    virtual IAsyncReadRequest* SizeRequest(FAsyncFileCallBack* CompleteCallback = nullptr) override
    {
        return new FAsyncReadRequestNull(CompleteCallback, true /* bInSizeRequest */);
    }
 
    virtual IAsyncReadRequest* ReadRequest(int64 Offset, int64 BytesToRead,
        EAsyncIOPriorityAndFlags PriorityAndFlags = AIOP_Normal, FAsyncFileCallBack* CompleteCallback = nullptr,
        uint8* UserSuppliedMemory = nullptr) override
    {
        return new FAsyncReadRequestNull(CompleteCallback, false /* bInSizeRequest */);
    }
 
    virtual bool UsesCache()
    {
        return false;
    }
};