//! Networking primitives for TCP/UDP communication.
//!
//! This module provides networking functionality for the Transmission Control and User
//! Datagram Protocols, as well as types for IP and socket addresses.
//!
//! # Organization
//!
//! * [`TcpListener`] and [`TcpStream`] provide functionality for communication over TCP
//! * [`UdpSocket`] provides functionality for communication over UDP
//! * [`IpAddr`] represents IP addresses of either IPv4 or IPv6; [`Ipv4Addr`] and
//!   [`Ipv6Addr`] are respectively IPv4 and IPv6 addresses
//! * [`SocketAddr`] represents socket addresses of either IPv4 or IPv6; [`SocketAddrV4`]
//!   and [`SocketAddrV6`] are respectively IPv4 and IPv6 socket addresses
//! * [`ToSocketAddrs`] is a trait that is used for generic address resolution when interacting
//!   with networking objects like [`TcpListener`], [`TcpStream`] or [`UdpSocket`]

mod socket_addr;
mod tcp;
mod udp;

pub use self::{
    socket_addr::{
        IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr, SocketAddrV4, SocketAddrV6, ToSocketAddrs,
    },
    tcp::{TcpListener, TcpStream},
    udp::UdpSocket,
};
use crate::io;

fn each_addr<A: ToSocketAddrs, F, T>(addr: A, mut f: F) -> io::Result<T>
where
    F: FnMut(io::Result<&SocketAddr>) -> io::Result<T>,
{
    let addrs = match addr.to_socket_addrs() {
        Ok(addrs) => addrs,
        Err(e) => return f(Err(e)),
    };
    let mut last_err = None;
    for addr in addrs {
        match f(Ok(&addr)) {
            Ok(l) => return Ok(l),
            Err(e) => last_err = Some(e),
        }
    }
    Err(last_err.unwrap_or_else(|| {
        ax_errno::ax_err_type!(InvalidInput, "could not resolve to any addresses")
    }))
}
