//! Unix socket options that behave the same on Linux and macOS.

use std::io;
use std::os::unix::net::UnixStream;
use std::time::Duration;

/// `EINVAL` on Darwin (`sys/errno.h`); std does not name it and a crate for one number is too much.
#[cfg(target_vendor = "apple")]
const EINVAL: i32 = 22;

/// Set the read timeout for the next read. macOS refuses every socket option with `EINVAL` once
/// the peer has closed (XNU `sosetoptlock`: both `SS_CANTRCVMORE` and `SS_CANTSENDMORE` set), even
/// with unread data still buffered. A read on such a socket returns that data or the end at once
/// and cannot block, so there is no timeout left to set and the refusal is not an error.
pub fn set_read_timeout(stream: &UnixStream, timeout: Duration) -> io::Result<()> {
    match stream.set_read_timeout(Some(timeout)) {
        #[cfg(target_vendor = "apple")]
        Err(e) if e.raw_os_error() == Some(EINVAL) => Ok(()),
        other => other,
    }
}