QXmppIqHandling.h

// SPDX-FileCopyrightText: 2022 Linus Jahn <lnj@kaidan.im>
//
// SPDX-License-Identifier: LGPL-2.1-or-later
 
#ifndef QXMPPIQHANDLING_H
#define QXMPPIQHANDLING_H
 
#include "QXmppClient.h"
#include "QXmppE2eeMetadata.h"
#include "QXmppFutureUtils_p.h"
#include "QXmppIq.h"
 
#include <QDomElement>
 
namespace QXmpp {
 
namespace Private {
 
    QXMPP_EXPORT void sendIqReply(QXmppClient *client,
                                  const QString &requestId,
                                  const QString &requestFrom,
                                  const std::optional<QXmppE2eeMetadata> &e2eeMetadata,
                                  QXmppIq &&iq);
 
    QXMPP_EXPORT std::tuple<bool, QString, QString> checkIsIqRequest(const QDomElement &el);
 
    template<typename... VariantTypes>
    void processHandleIqResult(QXmppClient *client,
                               const QString &requestId,
                               const QString &requestFrom,
                               const std::optional<QXmppE2eeMetadata> &e2eeMetadata,
                               std::variant<VariantTypes...> &&result)
    {
        std::visit([&](auto &&value) {
            using T = std::decay_t<decltype(value)>;
 
            static_assert(
                std::is_base_of_v<QXmppIq, T> || std::is_same_v<QXmppStanza::Error, T>,
                "QXmppIq based type or QXmppStanza::Error required");
 
            if constexpr (std::is_base_of_v<QXmppIq, T>) {
                sendIqReply(client, requestId, requestFrom, e2eeMetadata, std::move(value));
            } else if constexpr (std::is_same_v<QXmppStanza::Error, T>) {
                QXmppIq iq;
                iq.setType(QXmppIq::Error);
                iq.setError(value);
                sendIqReply(client, requestId, requestFrom, e2eeMetadata, std::move(iq));
            }
        },
                   std::move(result));
    }
 
    template<typename T>
    void processHandleIqResult(QXmppClient *client,
                               const QString &requestId,
                               const QString &requestFrom,
                               const std::optional<QXmppE2eeMetadata> &e2eeMetadata,
                               QXmppTask<T> future)
    {
        future.then(client, [client, requestId, requestFrom, e2eeMetadata](T result) {
            processHandleIqResult(client, requestId, requestFrom, e2eeMetadata, result);
        });
    }
 
    template<typename T, typename = std::enable_if_t<std::is_base_of_v<QXmppIq, T>, void>>
    void processHandleIqResult(QXmppClient *client,
                               const QString &requestId,
                               const QString &requestFrom,
                               const std::optional<QXmppE2eeMetadata> &e2eeMetadata,
                               T &&result)
    {
        sendIqReply(client, requestId, requestFrom, e2eeMetadata, std::move(result));
    }
 
    template<typename Handler, typename IqType>
    auto invokeIqHandler(Handler handler, IqType &&iq)
    {
        if constexpr (std::is_invocable<Handler, IqType &&>()) {
            return handler(std::move(iq));
        } else {
            return handler->handleIq(std::move(iq));
        }
    }
 
    template<typename IqType, typename Handler>
    bool handleIqType(Handler handler,
                      QXmppClient *client,
                      const QDomElement &element,
                      const std::optional<QXmppE2eeMetadata> &e2eeMetadata,
                      const QString &tagName,
                      const QString &xmlNamespace)
    {
        if (IqType::checkIqType(tagName, xmlNamespace)) {
            IqType iq;
            iq.parse(element);
            iq.setE2eeMetadata(e2eeMetadata);
 
            auto id = iq.id(), from = iq.from();
 
            processHandleIqResult(client, id, from, e2eeMetadata,
                                  invokeIqHandler(std::forward<Handler>(handler), std::move(iq)));
            return true;
        }
        return false;
    }
 
}  // namespace Private
 
template<typename... IqTypes, typename Handler>
bool handleIqRequests(const QDomElement &element,
                      const std::optional<QXmppE2eeMetadata> &e2eeMetadata,
                      QXmppClient *client,
                      Handler handler)
{
    if (auto [isRequest, tagName, xmlns] = Private::checkIsIqRequest(element); isRequest) {
        return (Private::handleIqType<IqTypes>(handler, client, element, e2eeMetadata, tagName, xmlns) || ...);
    }
    return false;
}
 
template<typename... IqTypes, typename Handler>
bool handleIqRequests(const QDomElement &element, QXmppClient *client, Handler handler)
{
    return handleIqRequests<IqTypes...>(element, std::nullopt, client, std::forward<Handler>(handler));
}
 
}  // namespace QXmpp
 
#endif  // QXMPPIQHANDLING_H