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#![forbid(unsafe_code)]
#![warn(missing_docs)]
use futures_core::{future::*, stream::*};
use futures_sink::Sink;
use futures_util::sink::SinkExt;
use futures_util::stream::StreamExt;
use futures_util::try_future::try_join_all;
use std::mem::drop;
use std::sync::{Arc, RwLock};
#[cfg(feature = "default-channels")]
use futures_channel::mpsc::*;
pub struct BroadcastChannel<
T,
#[cfg(feature = "default-channels")] S = UnboundedSender<T>,
#[cfg(feature = "default-channels")] R = UnboundedReceiver<T>,
#[cfg(not(feature = "default-channels"))] S,
#[cfg(not(feature = "default-channels"))] R,
> where
T: Send + Clone + 'static,
S: Send + Sync + Unpin + Clone + Sink<T>,
R: Unpin + Stream<Item = T>,
{
senders: Arc<RwLock<Vec<S>>>,
receiver: R,
ctor: Arc<dyn Fn() -> (S, R)>,
}
#[cfg(feature = "default-channels")]
impl<T: Send + Clone> BroadcastChannel<T> {
pub fn new() -> Self {
let (tx, rx) = unbounded();
Self {
senders: Arc::new(RwLock::new(vec![tx])),
receiver: rx,
ctor: Arc::new(unbounded),
}
}
}
#[cfg(feature = "default-channels")]
impl<T: Send + Clone> BroadcastChannel<T, Sender<T>, Receiver<T>> {
pub fn with_cap(cap: usize) -> Self {
let (tx, rx) = channel(cap);
Self {
senders: Arc::new(RwLock::new(vec![tx])),
receiver: rx,
ctor: Arc::new(move || channel(cap)),
}
}
}
impl<T, S, R> BroadcastChannel<T, S, R>
where
T: Send + Clone + 'static,
S: Send + Sync + Unpin + Clone + Sink<T>,
R: Unpin + Stream<Item = T>,
{
pub fn with_ctor(ctor: Arc<dyn Fn() -> (S, R)>) -> Self {
let (tx, rx) = ctor();
Self {
senders: Arc::new(RwLock::new(vec![tx])),
receiver: rx,
ctor,
}
}
pub async fn send(&self, item: &T) -> Result<(), S::Error> {
let guard = self.senders.read().expect("senders rwlock poisoned");
let mut senders = guard.clone();
drop(guard);
try_join_all(senders.iter_mut().map(|s| s.send(item.clone()))).await?;
Ok(())
}
pub fn recv(&mut self) -> impl Future<Output = Option<T>> + '_ {
self.receiver.next()
}
}
impl<T, S, R> Clone for BroadcastChannel<T, S, R>
where
T: Send + Clone + 'static,
S: Send + Sync + Unpin + Clone + Sink<T>,
R: Unpin + Stream<Item = T>,
{
fn clone(&self) -> Self {
let (tx, rx) = (self.ctor)();
self.senders
.write()
.expect("senders rwlock poisoned")
.push(tx);
Self {
senders: self.senders.clone(),
receiver: rx,
ctor: self.ctor.clone(),
}
}
}
#[cfg(all(feature = "default-channels", test))]
mod test {
use super::BroadcastChannel;
use futures_executor::block_on;
#[test]
fn send_recv() {
let mut chan = BroadcastChannel::new();
block_on(chan.send(&5)).unwrap();
assert_eq!(block_on(chan.recv()), Some(5));
}
#[test]
fn recv_two() {
let mut chan = BroadcastChannel::new();
let mut chan2 = chan.clone();
block_on(chan.send(&5)).unwrap();
assert_eq!(block_on(chan.recv()), Some(5));
assert_eq!(block_on(chan2.recv()), Some(5));
block_on(chan2.send(&6)).unwrap();
assert_eq!(block_on(chan.recv()), Some(6));
assert_eq!(block_on(chan2.recv()), Some(6));
}
}