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use crate::{
buffer::NetworkBuffer,
error::Result,
packet::{deserialize_packet_header, serialize_packet, Packet, PacketBody, PACKET_HEADER_SIZE},
send_bytes,
};
use mio::{net::TcpStream, Events, Interest, Poll, Token};
use std::{collections::VecDeque, io::Read};
const LOCAL_TOKEN: Token = Token(0);
const EVENTS_CAPACITY: usize = 4096;
pub enum ClientEvent {
Disconnected,
ReceivedPacket(usize),
SentPacket(usize),
#[doc(hidden)]
__Nonexhaustive,
}
pub struct Client {
tcp_stream: TcpStream,
events: Events,
poll: Poll,
buffer: NetworkBuffer,
incoming_packets: VecDeque<Packet>,
outgoing_packets: VecDeque<Box<dyn PacketBody>>,
is_disconnected: bool,
}
impl Client {
pub fn connect(ip: &str, port: u16) -> Result<Client> {
let address = format!("{}:{}", ip, port).parse().unwrap();
let mut tcp_stream = TcpStream::connect(address)?;
// Register for reading/writing
let poll = Poll::new().unwrap();
poll.registry().register(
&mut tcp_stream,
LOCAL_TOKEN,
Interest::READABLE | Interest::WRITABLE,
)?;
Ok(Client {
tcp_stream,
events: Events::with_capacity(EVENTS_CAPACITY),
poll,
buffer: NetworkBuffer::new(),
incoming_packets: VecDeque::new(),
outgoing_packets: VecDeque::new(),
is_disconnected: false,
})
}
pub fn is_disconnected(&self) -> bool {
self.is_disconnected
}
pub fn drain_incoming_packets(&mut self) -> Vec<Packet> {
self.incoming_packets.drain(..).collect()
}
pub fn send(&mut self, packet: impl PacketBody) {
let boxed = Box::new(packet);
self.outgoing_packets.push_back(boxed);
}
/// Runs a network tick, which sends/receives packets based on socket readiness
pub fn tick(&mut self) -> Vec<ClientEvent> {
if self.is_disconnected {
return Vec::new();
}
let timeout_dur = std::time::Duration::from_millis(1);
self.poll
.poll(&mut self.events, Some(timeout_dur))
.unwrap_or_else(|e| panic!("Failed to poll for events! {}", e));
let mut net_events: Vec<ClientEvent> = Vec::new();
for event in self.events.iter() {
match event.token() {
// Local socket is ready to read/write
LOCAL_TOKEN => {
// Handle reading
if event.is_readable() {
loop {
// Read until there are no more incoming bytes
match self
.tcp_stream
.read(&mut self.buffer.data[self.buffer.offset..])
{
Ok(0) => {
// "Read" 0 bytes, which means we have been disconnected
net_events.push(ClientEvent::Disconnected);
self.is_disconnected = true;
break;
}
Ok(read_bytes) => {
// Read some bytes
self.buffer.offset += read_bytes;
}
Err(e) => {
// Socket is not ready anymore, stop reading
if e.kind() == std::io::ErrorKind::WouldBlock {
break;
} else {
net_events.push(ClientEvent::Disconnected);
eprintln!("Unexpected error when reading bytes! {}", e);
self.is_disconnected = true;
break;
}
}
}
}
// Process incoming bytes into packets
while let Ok(header) = deserialize_packet_header(&mut self.buffer) {
// Now make sure we have enough bytes for at the rest of this packet
let packet_size = PACKET_HEADER_SIZE + (header.size as usize);
if self.buffer.offset < packet_size {
break;
}
// Drain the packet bytes from the front of the buffer
let bytes: &[u8] = &self.buffer.data[PACKET_HEADER_SIZE..packet_size];
let body = bytes.to_vec();
self.buffer.drain(packet_size);
let packet = Packet { header, body };
self.incoming_packets.push_back(packet);
net_events.push(ClientEvent::ReceivedPacket(packet_size));
}
}
// Handle writing
if event.is_writable() {
while let Some(packet) = self.outgoing_packets.pop_front() {
let data = match serialize_packet(packet) {
Ok(d) => d,
Err(e) => {
eprintln!("Failed to serialize packet! {}", e);
continue;
}
};
match send_bytes(&mut self.tcp_stream, &data) {
Ok(sent_bytes) => {
net_events.push(ClientEvent::SentPacket(sent_bytes));
}
Err(e) => {
net_events.push(ClientEvent::Disconnected);
eprintln!("Unexpected error when sending bytes! {}", e);
self.is_disconnected = true;
break;
}
}
}
}
}
_ => unreachable!(),
}
}
// We're done processing events for this tick.
// Reregister for next tick.
self.poll
.registry()
.reregister(
&mut self.tcp_stream,
LOCAL_TOKEN,
Interest::READABLE | Interest::WRITABLE,
)
.unwrap();
net_events
}
}