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use std::collections::HashMap;
use std::convert::TryInto;
use std::fmt;
use std::str;
use futures_channel::oneshot::{channel, Sender};
use crate::service::Service;
use crate::stream::RecvWriteStream;
use crate::task::spawn_local;
use crate::threadunsafe::ThreadUnsafeRefCell;
lazy_static! {
static ref SERVICE: Service = Service::register("peer");
static ref GROUPS: ThreadUnsafeRefCell<HashMap<Vec<u8>, Box<dyn Fn(&str, &str)>>> =
Default::default();
static ref CONNS: ThreadUnsafeRefCell<HashMap<(Vec<u8>, Vec<u8>), Sender<(RecvWriteStream, String)>>> =
Default::default();
}
pub async fn register_group(group_name: &str, listener: Box<dyn Fn(&str, &str)>) {
let mut groups = GROUPS.borrow_mut();
let init = groups.is_empty();
if let Some(_) = groups.insert(group_name.into(), listener) {
panic!("peer group {} already registered", group_name);
}
if init {
spawn_local(handle_info_packets());
SERVICE.send_info(&[]).await;
}
}
fn parse_name<'a>(b: &'a [u8]) -> (&'a [u8], &'a [u8]) {
let size = b[0] as usize;
let b = &b[1..];
let name = &b[..size];
let b = &b[size..];
(name, b)
}
async fn handle_info_packets() {
SERVICE
.recv_info(|b: &[u8]| {
let id = i32::from_le_bytes(b[..4].try_into().unwrap());
let b = &b[8..];
let (group_name, b) = parse_name(b);
let (peer_name, b) = parse_name(b);
let (type_name, _) = parse_name(b);
if id < 0 {
let groups = GROUPS.borrow();
groups[group_name](
str::from_utf8(peer_name).unwrap(),
str::from_utf8(type_name).unwrap(),
);
} else {
let stream = SERVICE.stream(id);
let mut conns = CONNS.borrow_mut();
let _ = conns
.remove(&(group_name.into(), peer_name.into()))
.unwrap()
.send((stream, String::from_utf8(type_name.into()).unwrap()));
}
})
.await;
}
pub async fn connect(
group_name: &str,
peer_name: &str,
type_name: &str,
) -> Result<(RecvWriteStream, String), ConnectError> {
let group_name = group_name.as_bytes();
if group_name.len() > 255 {
panic!("group name is too long");
}
let peer_name = peer_name.as_bytes();
if peer_name.len() > 255 {
panic!("peer name is too long");
}
let type_name = type_name.as_bytes();
if type_name.len() > 255 {
panic!("type name is too long");
}
let (sender, receiver) = channel();
{
let mut conns = CONNS.borrow_mut();
let key = (group_name.into(), peer_name.into());
if conns.get(&key).is_some() {
return Err(ConnectError::already_connecting());
}
conns.insert(key, sender);
}
let mut buf =
Vec::with_capacity(8 + 1 + group_name.len() + 1 + peer_name.len() + 1 + type_name.len());
buf.resize(8, 0);
buf.push(group_name.len() as u8);
buf.extend_from_slice(group_name);
buf.push(peer_name.len() as u8);
buf.extend_from_slice(peer_name);
buf.push(type_name.len() as u8);
buf.extend_from_slice(type_name);
SERVICE
.call(buf.as_slice(), |buf: &[u8]| -> Result<(), ConnectError> {
if buf.len() < 2 {
return Err(ConnectError::new(0));
}
let error = i16::from_le_bytes(buf[..2].try_into().unwrap());
match error {
0 => Ok(()),
1 => panic!("ABI violation"),
_ => Err(ConnectError::new(error)),
}
})
.await?;
Ok(receiver.await.unwrap())
}
#[derive(Debug, Eq, PartialEq)]
pub enum ConnectErrorKind {
Other,
GroupNotFound,
PeerNotFound,
Singularity,
AlreadyConnecting,
AlreadyConnected,
}
#[derive(Debug)]
pub struct ConnectError {
code: i16,
}
impl ConnectError {
fn new(code: i16) -> Self {
Self { code }
}
fn already_connecting() -> Self {
Self::new(5)
}
pub fn kind(&self) -> ConnectErrorKind {
match self.code {
2 => ConnectErrorKind::GroupNotFound,
3 => ConnectErrorKind::PeerNotFound,
4 => ConnectErrorKind::Singularity,
5 => ConnectErrorKind::AlreadyConnecting,
6 => ConnectErrorKind::AlreadyConnected,
_ => ConnectErrorKind::Other,
}
}
pub fn as_i16(&self) -> i16 {
self.code
}
}
impl fmt::Display for ConnectError {
fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
match self.kind() {
ConnectErrorKind::GroupNotFound => f.write_str("group not found"),
ConnectErrorKind::PeerNotFound => f.write_str("peer not found"),
ConnectErrorKind::Singularity => f.write_str("singularity"),
ConnectErrorKind::AlreadyConnecting => f.write_str("already connecting"),
ConnectErrorKind::AlreadyConnected => f.write_str("already connected"),
_ => self.code.fmt(f),
}
}
}