Module.h

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#pragma once
 
#include "REL/Version.h"
 
#include "REX/W32/KERNEL32.h"
 
namespace REL
{
    class Segment
    {
    public:
        enum Name : std::size_t
        {
            textx,
            idata,
            rdata,
            data,
            pdata,
            tls,
            textw,
            gfids,
            total
        };
 
        Segment() noexcept = default;
 
        Segment(std::uintptr_t a_proxyBase, std::uintptr_t a_address, std::uintptr_t a_size) noexcept :
            _proxyBase(a_proxyBase),
            _address(a_address),
            _size(a_size)
        {}
 
        [[nodiscard]] std::uintptr_t address() const noexcept { return _address; }
        [[nodiscard]] std::size_t    offset() const noexcept { return address() - _proxyBase; }
        [[nodiscard]] std::size_t    size() const noexcept { return _size; }
 
        [[nodiscard]] void* pointer() const noexcept { return reinterpret_cast<void*>(address()); }
 
        template <class T>
        [[nodiscard]] T* pointer() const noexcept
        {
            return static_cast<T*>(pointer());
        }
 
    private:
        std::uintptr_t _proxyBase{ 0 };
        std::uintptr_t _address{ 0 };
        std::size_t    _size{ 0 };
    };
 
    class Module
    {
    public:
        [[nodiscard]] static Module& get()
        {
            static Module singleton;
            return singleton;
        }
 
        [[nodiscard]] std::uintptr_t base() const noexcept { return _base; }
        [[nodiscard]] stl::zwstring  filename() const noexcept { return _filename; }
        [[nodiscard]] Version        version() const noexcept { return _version; }
 
        [[nodiscard]] Segment segment(Segment::Name a_segment) const noexcept { return _segments[a_segment]; }
 
        [[nodiscard]] REX::W32::HMODULE pointer() const noexcept { return reinterpret_cast<REX::W32::HMODULE>(base()); }
 
        template <class T>
        [[nodiscard]] T* pointer() const noexcept
        {
            return static_cast<T*>(pointer());
        }
 
    private:
        Module()
        {
            const auto getFilename = [&]() {
                return REX::W32::GetEnvironmentVariableW(
                    ENVIRONMENT.data(),
                    _filename.data(),
                    static_cast<std::uint32_t>(_filename.size()));
            };
 
            _filename.resize(getFilename());
            if (const auto result = getFilename();
                result != _filename.size() - 1 ||
                result == 0) {
#ifndef SKYRIMVR
                _filename = L"SkyrimSE.exe"sv;
#else
                _filename = L"SkyrimVR.exe"sv;
#endif
            }
 
            load();
        }
 
        Module(const Module&) = delete;
        Module(Module&&) = delete;
 
        ~Module() noexcept = default;
 
        Module& operator=(const Module&) = delete;
        Module& operator=(Module&&) = delete;
 
        void load()
        {
            auto handle = REX::W32::GetModuleHandleW(_filename.c_str());
            if (handle == nullptr) {
                stl::report_and_fail(
                    std::format(
                        "Failed to obtain module handle for: \"{0}\".\n"
                        "You have likely renamed the executable to something unexpected. "
                        "Renaming the executable back to \"{0}\" may resolve the issue."sv,
                        stl::utf16_to_utf8(_filename).value_or("<unicode conversion error>"s)));
            }
            _base = reinterpret_cast<std::uintptr_t>(handle);
 
            load_version();
            load_segments();
        }
 
        void load_segments();
 
        void load_version()
        {
            const auto version = GetFileVersion(_filename);
            if (version) {
                _version = *version;
            } else {
                stl::report_and_fail(
                    std::format(
                        "Failed to obtain file version info for: {}\n"
                        "Please contact the author of this script extender plugin for further assistance."sv,
                        stl::utf16_to_utf8(_filename).value_or("<unicode conversion error>"s)));
            }
        }
 
        static constexpr std::array SEGMENTS{
            std::make_pair(".text"sv, REX::W32::IMAGE_SCN_MEM_EXECUTE),
            std::make_pair(".idata"sv, 0u),
            std::make_pair(".rdata"sv, 0u),
            std::make_pair(".data"sv, 0u),
            std::make_pair(".pdata"sv, 0u),
            std::make_pair(".tls"sv, 0u),
            std::make_pair(".text"sv, REX::W32::IMAGE_SCN_MEM_WRITE),
            std::make_pair(".gfids"sv, 0u)
        };
 
        static constexpr auto ENVIRONMENT = L"SKSE_RUNTIME"sv;
 
        std::wstring                        _filename;
        std::array<Segment, Segment::total> _segments;
        Version                             _version;
        std::uintptr_t                      _base{ 0 };
    };
}