CppException.h

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/** @noop License Comment
 *  @file
 *  @copyright
 *  This Source Code is subject to the terms of the Mozilla Public License, v2.0.
 *  If a copy of the MPL was not distributed with this file You can obtain one at
 *  https://mozilla.org/MPL/2.0/
 *  
 *  @author David Mórász
 *  @date 2025
 */
 
#pragma once
 
#include "CoreMinimal.h"
#include "Mcro/Error.h"
 
#include <exception>
 
namespace Mcro::Error
{
    /**
     *  @brief
     *  Unreal itself discourages the usage of C++ exceptions and there are also couple of thoughts above IError why
     *  that's the case. However, there are third-party libraries which may require their users to catch errors, their
     *  functions may, yield via exceptions. For this reason there's an IError wrapper around std::exception base class
     *  which however will not preserve the actual type of the caught exception. For that use TCppException template.
     */
    class MCRO_API FCppException : public IError
    {
    public:
        FCppException(std::exception const& input);
        virtual ~FCppException() = default;
        
        virtual TSharedRef<SErrorDisplay> CreateErrorWidget() override;
 
        /** Storage for the exception but as the base STL type. It's copied to this member */
        std::exception BaseException;
 
    protected:
        virtual FStringView GetExceptionType() const;
        virtual void SerializeMembers(YAML::Emitter& emitter) const override;
    };
 
    /**
     *  @brief  Use this template for catching STL exceptions to preserve the exception type name. 
     *  @tparam Exception  Type of the encapsulated exception
     */
    template <CDerivedFrom<std::exception> Exception>
    class TCppException : public FCppException
    {
    public:
        TCppException(Exception const& input)
            : FCppException(input)
            , TypedException(input)
        {}
        
        /** @brief Storage for the exception but preserving its actual type. It's copied to this member */
        Exception TypedException;
        
    protected:
        virtual FStringView GetExceptionType() const override
        {
            return TTypeName<Exception>;
        }
    };
}