src/tools/broadcast_future.rs: cleanup, decompose into two classes

In order to make it more usable.
This commit is contained in:
Dietmar Maurer 2019-04-30 08:40:13 +02:00
parent d82ed9b0f5
commit 824b5ee4ee

View File

@ -4,15 +4,57 @@ use std::sync::{Mutex, Arc};
use futures::*;
use tokio::sync::oneshot;
struct BroadcastData<T> {
/// Broadcast results to registered listeners using asnyc oneshot channels
pub struct BroadcastData<T> {
result: Option<Result<T, String>>,
listeners: Vec<oneshot::Sender<Result<T, Error>>>,
source: Option<Box<Future<Item=T, Error=Error> + Send >>,
}
impl <T: Clone> BroadcastData<T> {
pub fn new() -> Self {
Self {
result: None,
listeners: vec![],
}
}
pub fn notify_listeners(&mut self, result: Result<T, String>) {
self.result = Some(result.clone());
loop {
match self.listeners.pop() {
None => { break; },
Some(ch) => {
match &result {
Ok(result) => { let _ = ch.send(Ok(result.clone())); },
Err(err) => { let _ = ch.send(Err(format_err!("{}", err))); },
}
},
}
}
}
pub fn listen(&mut self) -> impl Future<Item=T, Error=Error> {
match &self.result {
None => {},
Some(Ok(result)) => return futures::future::Either::A(futures::future::ok(result.clone())),
Some(Err(err)) => return futures::future::Either::A(futures::future::err(format_err!("{}", err))),
}
let (tx, rx) = oneshot::channel::<Result<T, Error>>();
self.listeners.push(tx);
futures::future::Either::B(rx.flatten())
}
}
/// Broadcast future results to registered listeners
pub struct BroadcastFuture<T> {
inner: Arc<Mutex<BroadcastData<T>>>,
inner: Arc<Mutex<(BroadcastData<T>, Option<Box<Future<Item=T, Error=Error> + Send>>)>>,
}
impl <T: Clone + Send + 'static> BroadcastFuture<T> {
@ -21,12 +63,7 @@ impl <T: Clone + Send + 'static> BroadcastFuture<T> {
///
/// The result of the future is sent to all registered listeners.
pub fn new(source: Box<Future<Item=T, Error=Error> + Send>) -> Self {
let data = BroadcastData {
result: None,
listeners: vec![],
source: Some(source),
};
Self { inner: Arc::new(Mutex::new(data)) }
Self { inner: Arc::new(Mutex::new((BroadcastData::new(), Some(source)))) }
}
/// Creates a new instance with a oneshot channel as trigger
@ -39,53 +76,30 @@ impl <T: Clone + Send + 'static> BroadcastFuture<T> {
(Self::new(test), tx)
}
fn update(inner: Arc<Mutex<BroadcastData<T>>>, result: Result<T, String>) {
fn notify_listeners(inner: Arc<Mutex<(BroadcastData<T>, Option<Box<Future<Item=T, Error=Error> + Send>>)>>, result: Result<T, String>) {
let mut data = inner.lock().unwrap();
data.result = Some(result.clone());
loop {
match data.listeners.pop() {
None => { break; },
Some(ch) => {
match &result {
Ok(result) => { let _ = ch.send(Ok(result.clone())); },
Err(err) => { let _ = ch.send(Err(format_err!("{}", err))); },
}
},
}
}
data.0.notify_listeners(result);
}
fn spawn(inner: Arc<Mutex<BroadcastData<T>>>) -> impl Future<Item=T, Error=Error> {
fn spawn(inner: Arc<Mutex<(BroadcastData<T>, Option<Box<Future<Item=T, Error=Error> + Send>>)>>) -> impl Future<Item=T, Error=Error> {
let mut data = inner.lock().unwrap();
match &data.result {
None => {},
Some(Ok(result)) => return futures::future::Either::A(futures::future::ok(result.clone())),
Some(Err(err)) => return futures::future::Either::A(futures::future::err(format_err!("{}", err))),
}
let (tx, rx) = oneshot::channel::<Result<T, Error>>();
data.listeners.push(tx);
if let Some(source) = data.source.take() {
if let Some(source) = data.1.take() {
let inner1 = inner.clone();
let task = source.then(move |value| {
match value {
Ok(value) => Self::update(inner1, Ok(value.clone())),
Err(err) => Self::update(inner1, Err(err.to_string())),
Ok(value) => Self::notify_listeners(inner1, Ok(value.clone())),
Err(err) => Self::notify_listeners(inner1, Err(err.to_string())),
}
Ok(())
});
tokio::spawn(task);
}
futures::future::Either::B(rx.map_err(Error::from).and_then(|result| { result }))
data.0.listen()
}
/// Register a listener