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use aleph_bft_types::{Network as NetworkT, NodeCount, NodeIndex, Recipient};
use async_trait::async_trait;
use futures::{
channel::mpsc::{unbounded, UnboundedReceiver, UnboundedSender},
Future, StreamExt,
};
use log::debug;
use std::{
cell::RefCell,
collections::HashMap,
pin::Pin,
task::{Context, Poll},
};
pub type NetworkReceiver<D> = UnboundedReceiver<(D, NodeIndex)>;
pub type NetworkSender<D> = UnboundedSender<(D, NodeIndex)>;
pub struct Network<D> {
rx: NetworkReceiver<D>,
tx: NetworkSender<D>,
peers: Vec<NodeIndex>,
index: NodeIndex,
}
impl<D> Network<D> {
pub fn new(
rx: NetworkReceiver<D>,
tx: NetworkSender<D>,
peers: Vec<NodeIndex>,
index: NodeIndex,
) -> Self {
Network {
rx,
tx,
peers,
index,
}
}
pub fn index(&self) -> NodeIndex {
self.index
}
}
#[async_trait::async_trait]
impl<D: Clone + Send> NetworkT<D> for Network<D> {
fn send(&self, data: D, recipient: Recipient) {
use Recipient::*;
match recipient {
Node(node) => self
.tx
.unbounded_send((data, node))
.expect("send on channel should work"),
Everyone => {
for peer in self.peers.iter() {
if *peer != self.index {
self.send(data.clone(), Node(*peer));
}
}
}
}
}
async fn next_event(&mut self) -> Option<D> {
Some(self.rx.next().await?.0)
}
}
pub struct Peer<D> {
tx: NetworkSender<D>,
rx: NetworkReceiver<D>,
}
#[async_trait]
pub trait NetworkHook<D>: Send {
async fn update_state(&mut self, data: &mut D, sender: NodeIndex, recipient: NodeIndex);
}
pub struct Router<D> {
peers: RefCell<HashMap<NodeIndex, Peer<D>>>,
peer_list: Vec<NodeIndex>,
hook_list: RefCell<Vec<Box<dyn NetworkHook<D>>>>,
reliability: f64,
}
impl<D> Router<D> {
pub fn new(n_members: NodeCount, reliability: f64) -> (Router<D>, Vec<Network<D>>) {
let peer_list = n_members.into_iterator().collect();
let mut router = Router {
peers: RefCell::new(HashMap::new()),
peer_list,
hook_list: RefCell::new(Vec::new()),
reliability,
};
let mut networks = Vec::new();
for ix in n_members.into_iterator() {
let network = router.connect_peer(ix);
networks.push(network);
}
(router, networks)
}
pub fn add_hook<HK: NetworkHook<D> + 'static>(&mut self, hook: HK) {
self.hook_list.borrow_mut().push(Box::new(hook));
}
pub fn connect_peer(&mut self, peer: NodeIndex) -> Network<D> {
assert!(
self.peer_list.iter().any(|p| *p == peer),
"Must connect a peer in the list."
);
assert!(
!self.peers.borrow().contains_key(&peer),
"Cannot connect a peer twice."
);
let (tx_in_hub, rx_in_hub) = unbounded();
let (tx_out_hub, rx_out_hub) = unbounded();
let peer_entry = Peer {
tx: tx_out_hub,
rx: rx_in_hub,
};
self.peers.borrow_mut().insert(peer, peer_entry);
Network::new(rx_out_hub, tx_in_hub, self.peer_list.clone(), peer)
}
}
impl<D> Future for Router<D> {
type Output = ();
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
let this = &mut self;
let mut disconnected_peers: Vec<NodeIndex> = Vec::new();
let mut buffer = Vec::new();
for (peer_id, peer) in this.peers.borrow_mut().iter_mut() {
loop {
match peer.rx.poll_next_unpin(cx) {
Poll::Ready(Some(msg)) => {
buffer.push((*peer_id, msg));
}
Poll::Ready(None) => {
disconnected_peers.push(*peer_id);
break;
}
Poll::Pending => {
break;
}
}
}
}
for peer_id in disconnected_peers {
this.peers.borrow_mut().remove(&peer_id);
}
for (sender, (mut data, recipient)) in buffer {
let rand_sample = rand::random::<f64>();
if rand_sample > this.reliability {
debug!("Simulated network fail.");
continue;
}
if let Some(peer) = this.peers.borrow().get(&recipient) {
for hook in this.hook_list.borrow_mut().iter_mut() {
match hook
.update_state(&mut data, sender, recipient)
.as_mut()
.poll(cx)
{
Poll::Ready(()) => (),
Poll::Pending => panic!(),
}
}
peer.tx
.unbounded_send((data, sender))
.expect("channel should be open");
}
}
if this.peers.borrow().is_empty() {
Poll::Ready(())
} else {
Poll::Pending
}
}
}
