openvehicle-api/global/exec_dir_helper.h

/********************************************************************************
 * Copyright (c) 2025-2026 ZF Friedrichshafen AG
 *
 * This program and the accompanying materials are made available under the 
 * terms of the Apache License Version 2.0 which is available at
 * https://www.apache.org/licenses/LICENSE-2.0
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Contributors:
 *   Erik Verhoeven - initial API and implementation
 ********************************************************************************/


#ifndef EXEC_DIR_HELPER_H
#define EXEC_DIR_HELPER_H

#include <filesystem>
#include <string>

#ifdef _WIN32
#pragma push_macro("interface")
#undef interface
#pragma push_macro("GetObject")
#undef GetObject

#ifndef NOMINMAX
#define NOMINMAX
#endif

#include <WinSock2.h>
#include <Windows.h>
#include <array>

// Resolve conflict
#pragma pop_macro("GetObject")
#pragma pop_macro("interface")
#ifdef GetClassInfo
#undef GetClassInfo
#endif
#elif defined __linux__
#include <linux/limits.h>
#include <unistd.h>
#else
#error OS is not supported
#endif

/**
 * @brief Get the absolute path to the currently run executable
 * @return Absolute std::filesystem::path to the currently run executable
 */
inline std::filesystem::path GetExecDirectory()
{
    static std::filesystem::path pathExeDir;
    if (!pathExeDir.empty()) return pathExeDir;
#ifdef _WIN32
    // Windows specific
    std::wstring ssPath(32768, '\0');
    GetModuleFileNameW(NULL, ssPath.data(), static_cast<DWORD>(ssPath.size() - 1));
#elif defined __linux__
    // Linux specific
    std::string ssPath(PATH_MAX + 1, '\0');
    const ssize_t nCount = readlink("/proc/self/exe", ssPath.data(), PATH_MAX);
    if (nCount < 0 || nCount >= PATH_MAX)
        return pathExeDir; // some error
    ssPath.at(nCount) = '\0';
#else
#error OS is not supported!
#endif
    pathExeDir = std::filesystem::path{ssPath.c_str()}.parent_path() / ""; // To finish the folder path with (back)slash
    return pathExeDir;
}

/**
 * @brief Get the filename of the currently run executable
 * @return The filename to the currently run executable
 */
inline std::filesystem::path GetExecFilename()
{
    static std::filesystem::path pathExeFilename;
    if (!pathExeFilename.empty()) return pathExeFilename;
#ifdef _WIN32
    // Windows specific
    std::wstring ssPath(32768, '\0');
    GetModuleFileNameW(NULL, ssPath.data(), static_cast<DWORD>(ssPath.size() - 1));
#elif defined __linux__
    // Linux specific
    std::string ssPath(PATH_MAX + 1, '\0');
    const ssize_t nCount = readlink("/proc/self/exe", ssPath.data(), PATH_MAX);
    if (nCount < 0 || nCount >= PATH_MAX)
        return pathExeFilename; // some error
    ssPath.at(nCount) = '\0';
#else
#error OS is not supported!
#endif
    pathExeFilename = std::filesystem::path{ssPath.c_str()}.filename();
    return pathExeFilename;
}

#endif // !defined EXEC_DIR_HELPER_H