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use std::io::{ErrorKind, Read, Write};
use std::net::{SocketAddr, TcpStream};
use std::time::{Duration, Instant};
use anyhow::Result;
use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
use serde::de::DeserializeOwned;
use serde::Serialize;
pub mod client;
pub mod server;
#[derive(Copy, Clone, Debug, Eq, Ord, PartialOrd, PartialEq)]
pub enum PacketReceiveStatus {
Received,
TimedOut
}
#[derive(Debug)]
pub struct Connection {
pub addr: SocketAddr,
pub stream: TcpStream,
}
pub(crate) fn block_until_receive(stream: &mut TcpStream, timeout: Duration) -> Result<PacketReceiveStatus> {
stream.set_nonblocking(true)?;
let start_time = Instant::now();
let mut buf = [0u8; 5];
loop {
if start_time.elapsed() > timeout {
break;
}
match stream.peek(&mut buf) {
Ok(peeked) => {
if peeked > 4 {
return Ok(PacketReceiveStatus::Received);
} else {
continue;
}
}
Err(err) => {
if err.kind() == ErrorKind::WouldBlock {
continue;
} else {
return Err(anyhow::Error::from(err));
}
}
}
}
Ok(PacketReceiveStatus::TimedOut)
}
pub(crate) fn read_packet<A: Serialize + DeserializeOwned>(stream: &mut TcpStream, blocking: bool) -> Result<Option<A>> {
let mut buf = [0u8; 5];
stream.set_nonblocking(!blocking)?;
let peek_bytes_res = stream.peek(&mut buf);
let peek_bytes = match peek_bytes_res {
Ok(peek_bytes) => peek_bytes,
Err(err) => {
return if err.kind() == ErrorKind::WouldBlock {
Ok(None)
} else {
Result::Err(anyhow::Error::from(err))
}
}
};
let mut result = Ok(None);
if peek_bytes > 4 {
stream.set_nonblocking(false)?;
let bytes = stream.read_u32::<LittleEndian>()? as usize;
let mut packet_bytes = vec![0; bytes];
match stream.read_exact(&mut packet_bytes) {
Ok(_) => {}
Err(err) => {
let kind = err.kind();
return if kind == ErrorKind::WouldBlock {
Ok(None)
} else {
Err(anyhow::Error::from(err))
}
}
}
let packet = bincode::deserialize(&packet_bytes)?;
result = Ok(Some(packet))
}
result
}
pub(crate) fn write_packet<A: Serialize + DeserializeOwned>(stream: &mut TcpStream, packet: &A) -> Result<()> {
let bytes = bincode::serialize(packet)?;
stream.set_nonblocking(false)?;
stream.write_u32::<LittleEndian>(bytes.len() as u32)?;
stream.write_all(&bytes)?;
stream.set_nonblocking(true)?;
Ok(())
}