SubProtocolFactorySelector.hpp

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/*
 * SNode.C - A Slim Toolkit for Network Communication
 * Copyright (C) Volker Christian <me@vchrist.at>
 *               2020, 2021, 2022, 2023, 2024, 2025, 2026
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published
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 * You should have received a copy of the GNU Lesser General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
 
/*
 * MIT License
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#include "web/websocket/SubProtocolFactorySelector.h"
 
#ifndef DOXYGEN_SHOULD_SKIP_THIS
 
#include "log/Logger.h"
 
#include <filesystem>
#include <list>
 
#endif /* DOXYGEN_SHOULD_SKIP_THIS */
 
namespace web::websocket {
 
    template <typename SubProtocolFactory>
    SubProtocolFactory* SubProtocolFactorySelector<SubProtocolFactory>::load(const std::string& subProtocolName,
                                                                             const std::string& subProtocolLibraryFile,
                                                                             const std::string& subProtocolFactoryFunctionName) {
        SubProtocolFactory* subProtocolFactory = nullptr;
 
        void* handle = core::DynamicLoader::dlOpen(subProtocolLibraryFile);
 
        if (handle != nullptr) {
            SubProtocolFactory* (*getSubProtocolFactory)() =
                reinterpret_cast<SubProtocolFactory* (*) ()>(core::DynamicLoader::dlSym(handle, subProtocolFactoryFunctionName));
            if (getSubProtocolFactory != nullptr) {
                subProtocolFactory = getSubProtocolFactory();
                if (subProtocolFactory != nullptr) {
                    subProtocolFactory->setHandle(handle);
                    LOG(DEBUG) << "WebSocket: SubProtocolFactory create success: " << subProtocolName;
                } else {
                    LOG(DEBUG) << "WebSocket: SubProtocolFactory create failed: " << subProtocolName;
                    core::DynamicLoader::dlClose(handle);
                }
            } else {
                LOG(DEBUG) << "WebSocket: Optaining function \"" << subProtocolFactoryFunctionName
                           << "\" in plugin failed: " << core::DynamicLoader::dlError();
                core::DynamicLoader::dlClose(handle);
            }
        }
 
        return subProtocolFactory;
    }
 
    template <typename SubProtocolFactory>
    SubProtocolFactory* SubProtocolFactorySelector<SubProtocolFactory>::select(const std::string& subProtocolName,
                                                                               [[maybe_unused]] Role role) {
        SubProtocolFactory* subProtocolFactory = nullptr;
 
        if (subProtocolFactories.contains(subProtocolName)) {
            subProtocolFactory = subProtocolFactories[subProtocolName];
 
            LOG(DEBUG) << "WebSocket subprotocol: plugin '" << subProtocolName << "' selected from dynamic cache";
        } else if (linkedSubProtocolFactories.contains(subProtocolName)) {
            SubProtocolFactory* (*plugin)() = linkedSubProtocolFactories[subProtocolName];
            subProtocolFactory = plugin();
 
            LOG(DEBUG) << "WebSocket subprotocol: plugin '" << subProtocolName << "' selected from static cache";
        } else if (!onlyLinked) {
            subProtocolFactory = load(subProtocolName);
            subProtocolFactories.insert({subProtocolName, subProtocolFactory});
 
            LOG(DEBUG) << "WebSocket subprotocol: plugin '" << subProtocolName << "' loaded and added to dynamic cache";
        } else {
            LOG(WARNING) << "WebSocket subprotocol: plugin '" << subProtocolName << "' not found";
        }
 
        return subProtocolFactory;
    }
 
    template <typename SubProtocolFactory>
    void SubProtocolFactorySelector<SubProtocolFactory>::allowDlOpen() {
        onlyLinked = false;
    }
 
} // namespace web::websocket