IPAddressAsyncResolve.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "Async/AsyncWork.h"
#include "IPAddress.h"
#include "Stats/Stats.h"
 
class FResolveInfo
{
protected:
    FResolveInfo()
    {
    }
 
public:
    virtual ~FResolveInfo()
    {
    }
 
    virtual bool IsComplete() const = 0;
 
    virtual int32 GetErrorCode() const = 0;
 
    virtual const FInternetAddr& GetResolvedAddress() const = 0;
};
 
class FResolveInfoCached : public FResolveInfo
{
protected:
    TSharedPtr<FInternetAddr> Addr;
 
    FResolveInfoCached() {}
 
public:
    FResolveInfoCached(const FInternetAddr& InAddr);
 
    // FResolveInfo interface
 
    virtual bool IsComplete() const
    {
        return true;
    }
 
    virtual int32 GetErrorCode() const
    {
        return 0;
    }
 
    virtual const FInternetAddr& GetResolvedAddress() const
    {
        return *Addr;
    }
};
 
//
// Class for creating a background thread to resolve a host.
//
class FResolveInfoAsync :
    public FResolveInfo
{
    //
    // A simple wrapper task that calls back to FResolveInfoAsync to do the actual work
    //
    class FResolveInfoAsyncWorker
    {
    public:
        FResolveInfoAsync* Parent;
 
        FResolveInfoAsyncWorker(FResolveInfoAsync* InParent)
            : Parent(InParent)
        {
        }
 
        void DoWork()
        {
            Parent->DoWork();
        }
 
        inline TStatId GetStatId() const
        {
            RETURN_QUICK_DECLARE_CYCLE_STAT(FResolveInfoAsyncWorker, STATGROUP_ThreadPoolAsyncTasks);
        }
 
        bool CanAbandon()
        {
            return true;
        }
 
        void Abandon()
        {
            FPlatformAtomics::InterlockedExchange(&Parent->bShouldAbandon, true);
        }
    };
    // Variables.
    TSharedPtr<FInternetAddr>   Addr;
    ANSICHAR    HostName[256];
    int32           ErrorCode;
    volatile int32 bShouldAbandon;
    FAsyncTask<FResolveInfoAsyncWorker> AsyncTask;
 
public:
    FResolveInfoAsync(const ANSICHAR* InHostName);
 
    void StartAsyncTask()
    {
        check(AsyncTask.GetTask().Parent == this); // need to make sure these aren't memcpy'd around after construction
        AsyncTask.StartBackgroundTask();
    }
 
    void DoWork();
 
    // FResolveInfo interface
 
    virtual bool IsComplete() const
    {
        // this semantically const, but IsDone syncs the async task, and that causes writes
        return const_cast<FAsyncTask<FResolveInfoAsyncWorker> &>(AsyncTask).IsDone();
    }
 
    virtual int32 GetErrorCode() const
    {
        return ErrorCode;
    }
 
    virtual const FInternetAddr& GetResolvedAddress() const
    {
        return *Addr;
    }
};