//! On Linux we try to use the more accurate `utimensat` syscall but this isn't

//! always available so we also fall back to `utimes` if we couldn't find

//! `utimensat` at runtime.

use crate::FileTime;

use std::ffi::CString;

use std::io;

use std::os::unix::prelude::*;

use std::path::Path;

use std::sync::atomic::AtomicBool;

use std::sync::atomic::Ordering::SeqCst;

pub fn set_symlink_file_times(p: &Path, atime: FileTime, mtime: FileTime) -> io::Result<()> {

    set_times(p, Some(atime), Some(mtime), true)

}

fn set_times(

    p: &Path,

    atime: Option<FileTime>,

    mtime: Option<FileTime>,

    symlink: bool,

) -> io::Result<()> {

    let flags = if symlink {

        libc::AT_SYMLINK_NOFOLLOW

    } else {

        0

    };

    // Same as the `if` statement above.

    static INVALID: AtomicBool = AtomicBool::new(false);

    if !INVALID.load(SeqCst) {

        let p = CString::new(p.as_os_str().as_bytes())?;

        let times = [super::to_timespec(&atime), super::to_timespec(&mtime)];

        let rc = unsafe { libc::utimensat(libc::AT_FDCWD, p.as_ptr(), times.as_ptr(), flags) };

        if rc == 0 {

            return Ok(());

        }

        let err = io::Error::last_os_error();

        if err.raw_os_error() == Some(libc::ENOSYS) {

            INVALID.store(true, SeqCst);

        } else {

            return Err(err);

        }

    }

    super::utimes::set_times(p, atime, mtime, symlink)

}