NativeExtension.hpp

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/*
 * Copyright (C) 2025  Tetex7
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
 
//
// Created by tete on 05/05/2025.
//
#pragma once
 
#ifndef L61_NATIVEEXTENSION_HPP
#define L61_NATIVEEXTENSION_HPP
#include <expected>
#include <mutex>
#include <stdexcept>
#include <type_traits>
 
#include "l61/defs.hpp"
#include "l61/RosettaSystem/loadSharedLibraryTypes.h"
#include "l61/BaseObjects/Object.hpp"
#include "l61/ExtensionSystem/ExtensionHeaders.hpp"
 
namespace l61::ExtensionSystem
{
class NativeExtension final : public Object
{
public:
    static constexpr const char* entryPointSymbolName = "__l61_rt_ex_init__";

    static constexpr const char* headerSymbolName = "__lex61_header__";
 
    using ExtensionEntryPoint_t = int(l61_api_extension_ptr);
    using ExtensionEntryPointPtr_t = std::add_pointer_t<ExtensionEntryPoint_t>;
    using ExtensionEntryPointCall_t = std::function<ExtensionEntryPoint_t>;
private:
    std::string extensionPath;

    l61_rosetta_SharedLibrary_handle_t soHandle;
    ExtensionEntryPointCall_t extensionEntryPointCall;

    mutable std::mutex soMutex;

    [[nodiscard]] l61_rosetta_SharedLibrary_symbol_t blindSymbolLookup(const std::string& symStr) const;
 
    void isGoodExtension() const;
public:
    static int safeExtensionLoad(const std::expected<NativeExtension, std::string>& extension, l61_api_extension_ptr api, bool required = true);

    static std::expected<NativeExtension, std::string> extensionLookUp(const std::vector<std::string>& spaths, const std::string& exName);

    [[nodiscard]] bool isValid() const;

    explicit NativeExtension(const std::string& path);

    [[nodiscard]]
    const ExtensionEntryPointCall_t& getExtensionEntryPointCall() const;

    [[nodiscard]]
    const std::string& getExtensionPath() const;

    std::string toString() const override;
 
    void unload();

    template<typename T>
    std::expected<std::add_pointer_t<std::type_identity_t<T>>, std::string> extensionSymbolLookup(const std::string& symStr) const
    {
        try
        {
            //This is very spooky but trust me Bro it's this way, or it does not work
            //And yes this does break my rule of self enforced strict aliasing
            return reinterpret_cast<std::add_pointer_t<T>>(blindSymbolLookup(symStr));
        }
        catch (std::runtime_error& e)
        {
            return std::unexpected(e.what());
        }
    }

    const lex61_header_t* getExtensionHeader() const;
 
    __inline const lex61_header_t& getExtensionHeaderAsRef() const
    {
        return *getExtensionHeader();
    }
 
    ~NativeExtension() override;
    NativeExtension(NativeExtension&) = delete;
    NativeExtension(const NativeExtension&) = delete;
    NativeExtension(NativeExtension&& nativeExtension) noexcept;
};
}
 
#endif //L61_NATIVEEXTENSION_HPP