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// //! A threadsafe multi-consumer-stream.
//
// // TODO ensure this implements Send and the other relevant trait
//
// use std::cell::RefCell;
// use std::hash::Hash;
// use std::sync::{Arc, Mutex};
//
// use futures_core::{Poll, Stream};
// use futures_core::task::Context;
//
// use shared::Shared;
//
// /// Wraps a stream and provides a multi-consumer-stream.
// ///
// /// This structs allows to create new `MCSHandle`, which receive all the items/errors for which
// /// the `ItemFn`/`ErrFn` compute a certain key. All items/errors for which no corresponding
// /// `MCSHandle` exist are routed to the primary `MCS`.
// pub struct MCS<S: Stream, Key: Eq + Hash + Copy, ItemFn, ErrFn>(Arc<Mutex<RefCell<Shared<S,
// Key,
// ItemFn,
// ErrFn>>>>);
//
// impl<S, Key, ItemFn, ErrFn> MCS<S, Key, ItemFn, ErrFn>
// where S: Stream,
// Key: Eq + Hash + Copy
// {
// /// Create a new `MCS` with the given functions to compute keys.
// pub fn new(stream: S, item_fn: ItemFn, err_fn: ErrFn) -> MCS<S, Key, ItemFn, ErrFn> {
// MCS(Arc::new(Mutex::new(RefCell::new(Shared::new(stream, item_fn, err_fn)))))
// }
// }
//
// impl<S, Key, ItemFn, ErrFn> MCS<S, Key, ItemFn, ErrFn>
// where S: Stream,
// Key: Eq + Hash + Copy,
// ItemFn: Fn(&S::Item) -> Key,
// ErrFn: Fn(&S::Error) -> Key
// {
// /// Consume the `MCS` and retrieve ownership of the wrapped stream.
// ///
// /// Polling an `MCSHandle` after consuming its `MCS` panics.
// pub fn into_inner(self) -> S {
// self.0.borrow_mut().inner.take().unwrap()
// }
//
// /// Create a `MCSHandle` to the underlying stream. The handle receives all items for which the
// /// `MCS`'s `item_fn` returns `key`, and all errors for which the `MCS`'s `error_fn` returns
// /// `key`.
// ///
// /// Panics if there is already a handle for that key.
// pub fn mcs_handle(&self, key: Key) -> MCSHandle<S, Key, ItemFn, ErrFn> {
// MCSHandle::new(self.0.clone(), key)
// }
//
// /// Create a `MCSHandle` to the underlying stream. The handle receives all items for which the
// /// `MCS`'s `item_fn` returns `key`, and all errors for which the `MCS`'s `error_fn` returns
// /// `key`.
// ///
// /// This returns `None` if there is already a handle for that key.
// pub fn try_mcs_handle(&self, key: Key) -> Option<MCSHandle<S, Key, ItemFn, ErrFn>> {
// MCSHandle::try_new(self.0.clone(), key)
// }
// }
//
// impl<S, Key, ItemFn, ErrFn> Stream for MCS<S, Key, ItemFn, ErrFn>
// where S: Stream,
// Key: Copy + Eq + Hash,
// ItemFn: Fn(&S::Item) -> Key,
// ErrFn: Fn(&S::Error) -> Key
// {
// type Item = S::Item;
// type Error = S::Error;
//
// fn poll_next(&mut self, cx: &mut Context) -> Poll<Option<Self::Item>, Self::Error> {
// self.0.borrow_mut().poll_default(cx)
// }
// }
//
// /// A stream that receives all items/errors for which the corresponding `MCS`'s `item_fn`/`err_fn`
// /// return the key from which the `MCSHandle` was constructed.
// pub struct MCSHandle<S: Stream, Key: Eq + Hash + Copy, ItemFn, ErrFn> {
// shared: Arc<Mutex<RefCell<Shared<S, Key, ItemFn, ErrFn>>>>,
// key: Key,
// }
//
// impl<S, Key, ItemFn, ErrFn> MCSHandle<S, Key, ItemFn, ErrFn>
// where S: Stream,
// Key: Eq + Hash + Copy
// {
// fn new(shared: Arc<Mutex<RefCell<Shared<S, Key, ItemFn, ErrFn>>>>,
// key: Key)
// -> MCSHandle<S, Key, ItemFn, ErrFn> {
// assert!(shared.borrow_mut().register_key(key.clone()),
// "Tried to register duplicate handles");
// MCSHandle { shared, key }
// }
//
// fn try_new(shared: Arc<Mutex<RefCell<Shared<S, Key, ItemFn, ErrFn>>>>,
// key: Key)
// -> Option<MCSHandle<S, Key, ItemFn, ErrFn>> {
// if shared.borrow_mut().register_key(key.clone()) {
// Some(MCSHandle { shared, key })
// } else {
// None
// }
// }
//
// /// Create a `MCSHandle` to the underlying stream. The handle receives all items for which the
// /// corresponding `MCS`'s `item_fn` returns `key`, and all errors for which the `MCS`'s
// /// `error_fn` returns `key`.
// ///
// /// Panics if there is already a handle for that key.
// pub fn mcs_handle(&self, key: Key) -> MCSHandle<S, Key, ItemFn, ErrFn> {
// MCSHandle::new(self.shared.clone(), key)
// }
//
// /// Create a `MCSHandle` to the underlying stream. The handle receives all items for which the
// /// corresponding `MCS`'s `item_fn` returns `key`, and all errors for which the `MCS`'s
// /// `error_fn` returns `key`.
// ///
// /// This returns `None` if there is already a handle for that key.
// pub fn try_mcs_handle(&self, key: Key) -> Option<MCSHandle<S, Key, ItemFn, ErrFn>> {
// MCSHandle::try_new(self.shared.clone(), key)
// }
// }
//
// impl<S, Key, ItemFn, ErrFn> Drop for MCSHandle<S, Key, ItemFn, ErrFn>
// where S: Stream,
// Key: Eq + Hash + Copy
// {
// /// Deregisters the key of this `KeyMCS`.
// fn drop(&mut self) {
// self.shared.borrow_mut().deregister_key(&self.key);
// }
// }
//
// impl<S, Key, ItemFn, ErrFn> Stream for MCSHandle<S, Key, ItemFn, ErrFn>
// where S: Stream,
// Key: Eq + Hash + Copy,
// ItemFn: Fn(&S::Item) -> Key,
// ErrFn: Fn(&S::Error) -> Key
// {
// type Item = S::Item;
// type Error = S::Error;
//
// fn poll_next(&mut self, cx: &mut Context) -> Poll<Option<Self::Item>, Self::Error> {
// self.shared.borrow_mut().poll_handle(self.key, cx)
// }
// }
//
// #[cfg(test)]
// mod tests {
// use super::*;
//
// use atm_async_utils::test_channel::*;
// use futures::{SinkExt, StreamExt, FutureExt, Never};
// use futures::sink::close;
// use futures::stream::iter_ok;
// use futures::executor::block_on;
//
// #[test]
// fn it_works() {
// let (sender, receiver) = test_channel(2);
//
// let default: MCS<TestReceiver<u32, u32>, u8, fn(&u32) -> u8, fn(&u32) -> u8> =
// MCS::new(receiver,
// |x| match x {
// y if y % 3 == 0 => 1,
// y if y % 5 == 0 => 2,
// _ => 0,
// },
// |x| match x {
// y if y % 3 == 0 => 1,
// y if y % 5 == 0 => 2,
// _ => 0,
// });
// let s1 = default.mcs_handle(1);
// let s2 = default.mcs_handle(2);
//
// let sending = sender
// .send_all(iter_ok::<_, Never>(0..40).map(|i| if i % 2 == 0 {
// Ok(i / 2)
// } else {
// Err(i / 2)
// }))
// .and_then(|(sender, _)| close(sender));
//
// let (_, threes, fives, defaults) =
// block_on(sending.join4(s1.then(|result| match result {
// Ok(foo) => Ok(Ok(foo)),
// Err(err) => Ok(Err(err)),
// })
// .collect(),
// s2.then(|result| match result {
// Ok(foo) => Ok(Ok(foo)),
// Err(err) => Ok(Err(err)),
// })
// .collect(),
// default
// .then(|result| match result {
// Ok(foo) => Ok(Ok(foo)),
// Err(err) => Ok(Err(err)),
// })
// .collect()))
// .unwrap();
//
// assert_eq!(threes,
// vec![Ok(0), Err(0), Ok(3), Err(3), Ok(6), Err(6), Ok(9), Err(9), Ok(12),
// Err(12), Ok(15), Err(15), Ok(18), Err(18)]);
// assert_eq!(fives, vec![Ok(5), Err(5), Ok(10), Err(10)]);
// assert_eq!(defaults,
// vec![Ok(1), Err(1), Ok(2), Err(2), Ok(4), Err(4), Ok(7), Err(7), Ok(8),
// Err(8), Ok(11), Err(11), Ok(13), Err(13), Ok(14), Err(14), Ok(16),
// Err(16), Ok(17), Err(17), Ok(19), Err(19)]);
// }
// }