//// Dis VM// File: file_system.cpp// Author: arr// #include <iostream>#include <fstream>#include <mutex>#include <utils.h>#include "sys_utils.h" using namespace disvm::runtime; namespace{    std::mutex _create_file_stream_mutex;} std::unique_ptr<std::fstream> disvm::runtime::sys::create_file_stream(const char *path, std::ios::openmode mode, cfs_flags_t flags){    auto file = std::unique_ptr<std::fstream>{};    if (flags == cfs_flags_t::none)    {        file = std::make_unique<std::fstream>(path, mode);    }    else    {        std::unique_lock<std::mutex> lock{ _create_file_stream_mutex, std::defer_lock };        if (util::has_flag(flags, cfs_flags_t::atomic))            lock.lock();         if (util::has_flag(flags, cfs_flags_t::ensure_create))        {            std::fstream file_exists{ path };            if (file_exists)                return{};        }         file = std::make_unique<std::fstream>(path, mode);    }     // Return null if file stream is not open.    if (!file->is_open())        return{};     return file;}