//! Linux `statx`.

use crate::fd::{AsFd, BorrowedFd};

use crate::ffi::CStr;

use crate::fs::AtFlags;

use crate::{backend, io, path};

use core::sync::atomic::{AtomicU8, Ordering};

pub use backend::fs::types::{Statx, StatxFlags, StatxTimestamp};

/// `statx(dirfd, path, flags, mask, statxbuf)`

///

/// This function returns [`io::Errno::NOSYS`] if `statx` is not available on

/// the platform, such as Linux before 4.11. This also includes older Docker

/// versions where the actual syscall fails with different error codes; Rustix

/// handles this and translates them into `NOSYS`.

///

/// # References

///  - [Linux]

///

/// [Linux]: https://man7.org/linux/man-pages/man2/statx.2.html

#[inline]

pub fn statx<P: path::Arg, Fd: AsFd>(

    dirfd: Fd,

    path: P,

    flags: AtFlags,

    mask: StatxFlags,

) -> io::Result<Statx> {

    path.into_with_c_str(|path| _statx(dirfd.as_fd(), path, flags, mask))

}

// Linux kernel prior to 4.11 old versions of Docker don't support `statx`. We

// store the availability in a global to avoid unnecessary syscalls.

//

// 0: Unknown

// 1: Not available

// 2: Available

static STATX_STATE: AtomicU8 = AtomicU8::new(0);

#[inline]

fn _statx(

    dirfd: BorrowedFd<'_>,

    path: &CStr,

    flags: AtFlags,

    mask: StatxFlags,

) -> io::Result<Statx> {

    match STATX_STATE.load(Ordering::Relaxed) {

        0 => statx_init(dirfd, path, flags, mask),

        1 => Err(io::Errno::NOSYS),

        _ => backend::fs::syscalls::statx(dirfd, path, flags, mask),

    }

}

/// The first `statx` call. We don't know if `statx` is available yet.

        }

    }

/// The first `statx` call failed with `NOSYS` (or something we're treating

/// like `NOSYS`).

#[cold]

/// The first `statx` call failed with `PERM`.

#[cold]

    } else {

    }