handlenetworkreply.h

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/**********************************************************************
 * LeechCraft - modular cross-platform feature rich internet client.
 * Copyright (C) 2006-2014  Georg Rudoy
 *
 * Boost Software License - Version 1.0 - August 17th, 2003
 *
 * Permission is hereby granted, free of charge, to any person or organization
 * obtaining a copy of the software and accompanying documentation covered by
 * this license (the "Software") to use, reproduce, display, distribute,
 * execute, and transmit the Software, and to prepare derivative works of the
 * Software, and to permit third-parties to whom the Software is furnished to
 * do so, all subject to the following:
 *
 * The copyright notices in the Software and this entire statement, including
 * the above license grant, this restriction and the following disclaimer,
 * must be included in all copies of the Software, in whole or in part, and
 * all derivative works of the Software, unless such copies or derivative
 * works are solely in the form of machine-executable object code generated by
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 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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#pragma once
 
#include <QNetworkReply>
#include <util/sll/slotclosure.h>
#include <util/sll/either.h>
#include <util/sll/overload.h>
#include <util/sll/void.h>
#include <util/sll/typelist.h>
#include <util/threads/futures.h>
#include "networkconfig.h"
 
namespace LC
{
namespace Util
{
    template<typename F>
    void HandleNetworkReply (QObject *context, QNetworkReply *reply, F f)
    {
        new Util::SlotClosure<Util::DeleteLaterPolicy>
        {
            [reply, f]
            {
                reply->deleteLater ();
                f (reply->readAll ());
            },
            reply,
            SIGNAL (finished ()),
            context
        };
    }
 
    template<typename>
    struct ErrorInfo;
 
    template<typename>
    struct ResultInfo;
 
    struct UTIL_NETWORK_API ReplyWithHeaders
    {
        QByteArray Data_;
        QHash<QByteArray, QList<QByteArray>> Headers_;
 
        explicit ReplyWithHeaders (QNetworkReply*);
    };
 
    struct UTIL_NETWORK_API ReplyError
    {
        QNetworkReply::NetworkError Error_;
        QString ErrorString_;
 
        QVariant HttpStatusCode_;
 
        explicit ReplyError (QNetworkReply*);
    };
 
    template<typename... Args>
    auto HandleReply (QNetworkReply *reply, QObject *context)
    {
        using Err = Find<ErrorInfo, Util::Void, Args...>;
        using Res = Find<ResultInfo, QByteArray, Args...>;
 
        using Result_t = Util::Either<Err, Res>;
        QFutureInterface<Result_t> promise;
        promise.reportStarted ();
 
        QObject::connect (reply,
                &QNetworkReply::finished,
                context,
                [promise, reply] () mutable
                {
                    reply->deleteLater ();
 
                    if constexpr (std::is_same_v<Res, QByteArray>)
                        Util::ReportFutureResult (promise, Result_t::Right (reply->readAll ()));
                    else if constexpr (std::is_same_v<Res, ReplyWithHeaders>)
                        Util::ReportFutureResult (promise, Result_t::Right (Res { reply }));
                    else
                        static_assert (std::is_same_v<Res, struct Dummy>, "Unsupported reply type");
                });
        QObject::connect (reply,
                Util::Overload<QNetworkReply::NetworkError> (&QNetworkReply::error),
                context,
                [promise, reply] () mutable
                {
                    reply->deleteLater ();
 
                    auto report = [&] (const Err& val) { Util::ReportFutureResult (promise, Result_t::Left (val)); };
 
                    if constexpr (std::is_same_v<Err, QString>)
                        report (reply->errorString ());
                    else if constexpr (std::is_same_v<Err, Util::Void>)
                        report ({});
                    else if constexpr (std::is_same_v<Err, ReplyError>)
                        report (Err { reply });
                    else
                        static_assert (std::is_same_v<Err, struct Dummy>, "Unsupported error type");
                });
 
        return promise.future ();
    }
 
    template<typename... Args>
    auto HandleReplySeq (QNetworkReply *reply, QObject *context)
    {
        return Sequence (context, HandleReply<Args...> (reply, context));
    }
}
}