memgraph/include/utils/sys.hpp

#pragma once

#include <cassert>
#include <errno.h>
#include <fstream>
#include <linux/futex.h>
#include <stdio.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>

namespace sys
{
// Code from stackoverflow:
// http://stackoverflow.com/questions/676787/how-to-do-fsync-on-an-ofstream
// Extracts FILE* from streams in std.
inline int GetFileDescriptor(std::filebuf &filebuf)
{
    class my_filebuf : public std::filebuf
    {
    public:
        int handle() { return _M_file.fd(); }
    };

    return static_cast<my_filebuf &>(filebuf).handle();
}

inline int futex(void *addr1, int op, int val1, const struct timespec *timeout,
                 void *addr2, int val3)
{
    return syscall(SYS_futex, addr1, op, val1, timeout, addr2, val3);
};

// Ensures that everything written to file will be writen on disk when the
// function call returns. !=0 if error occured
template <class STREAM>
inline size_t flush_file_to_disk(STREAM &file)
{
    file.flush();
    if (fsync(GetFileDescriptor(*file.rdbuf())) == 0) {
        return 0;
    }

    return errno;
};

// True if succesffull
inline bool ensure_directory_exists(std::string const &path)
{
    struct stat st = {0};

    if (stat(path.c_str(), &st) == -1) {
        return mkdir(path.c_str(), S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH) == 0;
    }
    return true;
}
};