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use crate::*;
pub struct Selector<'a, T: 'a> {
selections: Vec<(
Box<dyn FnMut() -> Option<T> + 'a>,
Box<dyn FnMut() + 'a>,
)>,
signal: Arc<SelectorSignal>,
}
impl<'a, T: 'a> Selector<'a, T> {
pub fn new() -> Self {
Self {
selections: Vec::new(),
signal: Arc::new(SelectorSignal {
wait_lock: Mutex::new(None),
trigger: Condvar::new(),
}),
}
}
pub fn send<U>(mut self, sender: &'a Sender<U>, msg: U, mut f: impl FnMut(Result<(), SendError<U>>) -> T + 'a) -> Self {
let token = self.selections.len();
let selector_id = sender.shared.connect_send_selector(self.signal.clone(), token);
let mut msg = Some(msg);
self.selections.push((
Box::new(move || {
if let Some(m) = msg.take() {
match sender.try_send(m) {
Ok(()) => {
msg = None;
Some((&mut f)(Ok(())))
},
Err(TrySendError::Disconnected(m)) => {
msg = None;
Some((&mut f)(Err(SendError(m))))
},
Err(TrySendError::Full(m)) => {
msg = Some(m);
None
},
}
} else {
None
}
}),
Box::new(move || sender.shared.disconnect_send_selector(selector_id)),
));
self
}
pub fn recv<U>(mut self, receiver: &'a Receiver<U>, mut f: impl FnMut(Result<U, RecvError>) -> T + 'a) -> Self {
let token = self.selections.len();
receiver.shared.connect_recv_selector(self.signal.clone(), token);
self.selections.push((
Box::new(move || match receiver.try_recv() {
Ok(msg) => Some((&mut f)(Ok(msg))),
Err(TryRecvError::Empty) => None,
Err(TryRecvError::Disconnected) => Some((&mut f)(Err(RecvError::Disconnected))),
}),
Box::new(move || receiver.shared.disconnect_recv_selector()),
));
self
}
fn wait_inner(&mut self) -> T {
if let Some(msg) = self.poll() {
return msg;
}
loop {
let mut guard = self.signal.wait_lock.lock().unwrap();
*guard = None;
let token = *self.signal.trigger.wait(guard).unwrap();
if let Some(msg) = match token {
None => self.poll(),
Some(token) => (&mut self.selections[token].0)()
} {
break msg;
}
}
}
pub fn poll(&mut self) -> Option<T> {
self
.selections
.iter_mut()
.find_map(|(poll, _)| poll())
}
pub fn wait(&mut self) -> T {
self.wait_inner()
}
pub fn iter<'b: 'a>(&'b mut self) -> SelectorIter<'b, T> {
SelectorIter { selector: self }
}
pub fn try_iter<'b: 'a>(&'b mut self) -> SelectorTryIter<'b, T> {
SelectorTryIter { selector: self }
}
}
pub struct SelectorIter<'a, T: 'a> {
selector: &'a mut Selector<'a, T>,
}
impl<'a, T> Iterator for SelectorIter<'a, T> {
type Item = T;
fn next(&mut self) -> Option<Self::Item> {
Some(self.selector.wait_inner())
}
}
pub struct SelectorTryIter<'a, T: 'a> {
selector: &'a mut Selector<'a, T>,
}
impl<'a, T> Iterator for SelectorTryIter<'a, T> {
type Item = T;
fn next(&mut self) -> Option<Self::Item> {
self.selector.poll()
}
}
impl<'a, T> Drop for Selector<'a, T> {
fn drop(&mut self) {
for (_, drop) in self.selections.iter_mut() {
drop();
}
}
}