AsyncResult.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreTypes.h"
#include "Async/Future.h"
 
class IAsyncProgress;
class IAsyncTask;
 
template<typename ResultType>
class TAsyncResult
{
public:
 
    TAsyncResult() { }
 
    template <typename ArgType,
              typename = std::enable_if_t<std::is_same_v<ArgType, ResultType> && std::is_reference_v<const ArgType&>>>
    TAsyncResult(const ArgType& Result)
    {
        TPromise<ResultType> Promise;
        Promise.SetValue(Result);
        Future = Promise.GetFuture();
    }
 
    TAsyncResult(TFuture<ResultType>&& InFuture, const TSharedPtr<IAsyncProgress>& InProgress, const TSharedPtr<IAsyncTask>& InTask)
        : Future(MoveTemp(InFuture))
        , Progress(InProgress)
        , Task(InTask)
    { }
 
    TAsyncResult(TAsyncResult&& Other)
        : Future(MoveTemp(Other.Future))
        , Progress(Other.Progress)
        , Task(Other.Task)
    {
        Other.Progress.Reset();
        Other.Task.Reset();
    }
 
public:
 
    TAsyncResult& operator=(TAsyncResult&& Other)
    {
        Future = MoveTemp(Other.Future);
        Progress = Other.Progress;
        Task = Other.Task;
 
        Other.Progress.Reset();
        Other.Task.Reset();
 
        return *this;
    }
 
public:
 
    const TFuture<ResultType>& GetFuture() const
    {
        return Future;
    }
 
    TSharedPtr<IAsyncProgress> GetProgess() const
    {
        return Progress;
    }
 
    TSharedPtr<IAsyncTask> GetTask() const
    {
        return Task;
    }
 
private:
 
    TAsyncResult(const TAsyncResult&);
 
    TAsyncResult& operator=(const TAsyncResult&);
 
private:
 
    TFuture<ResultType> Future;
 
    TSharedPtr<IAsyncProgress> Progress;
 
    TSharedPtr<IAsyncTask> Task;
};