danceinterpreter-rs 0.6.1

Danceinterpreter in Rust
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use iced::advanced::graphics::futures::{boxed_stream, BoxStream, MaybeSend};
use iced::advanced::subscription::{from_recipe, EventStream, Hasher, Recipe};
use iced::futures::stream::FusedStream;
use iced::futures::{ready, Stream};
use iced::Subscription;
use pin_project_lite::pin_project;
use std::future::Future;
use std::hash::Hash;
use std::pin::Pin;
use std::task::{Context, Poll};

pin_project! {
    pub struct DroppingOnce<Fut, DropFn>
    where
        Fut: Future,
        DropFn: FnOnce() -> (),
    {
        #[pin]
        future: Option<Fut>,
        drop_fn: Option<DropFn>,
    }

    impl<Fut: Future, DropFn: FnOnce() -> ()> PinnedDrop for DroppingOnce<Fut, DropFn> {
        fn drop(this: Pin<&mut Self>) {
            let this = this.project();
            if let Some(drop_fn) = this.drop_fn.take() {
                drop_fn();
            }
        }
    }
}

impl<Fut: Future, DropFn: FnOnce() -> ()> DroppingOnce<Fut, DropFn> {
    pub fn new(future: Fut, drop_fn: DropFn) -> Self {
        Self {
            future: Some(future),
            drop_fn: Some(drop_fn),
        }
    }
}

impl<Fut: Future, DropFn: FnOnce() -> ()> Stream for DroppingOnce<Fut, DropFn> {
    type Item = Fut::Output;

    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
        let mut this = self.project();
        let v = match this.future.as_mut().as_pin_mut() {
            Some(fut) => ready!(fut.poll(cx)),
            None => return Poll::Ready(None),
        };

        this.future.set(None);
        Poll::Ready(Some(v))
    }

    fn size_hint(&self) -> (usize, Option<usize>) {
        if self.future.is_some() {
            (1, Some(1))
        } else {
            (0, Some(0))
        }
    }
}

impl<Fut: Future, DropFn: FnOnce() -> ()> FusedStream for DroppingOnce<Fut, DropFn> {
    fn is_terminated(&self) -> bool {
        self.future.is_none()
    }
}

// TODO: replace with Subscription::run_with once the update comes out
pub fn run_subscription_with<T, D, S>(data: D, builder: fn(&D) -> S) -> Subscription<T>
where
    D: Hash + 'static,
    S: Stream<Item = T> + MaybeSend + 'static,
    T: 'static,
{
    struct Runner<I, F, S, T>
    where
        F: FnOnce(&I, EventStream) -> S,
        S: Stream<Item = T>,
    {
        data: I,
        spawn: F,
    }

    impl<I, F, S, T> Recipe for Runner<I, F, S, T>
    where
        I: Hash + 'static,
        F: FnOnce(&I, EventStream) -> S,
        S: Stream<Item = T> + MaybeSend + 'static,
    {
        type Output = T;

        fn hash(&self, state: &mut Hasher) {
            std::any::TypeId::of::<I>().hash(state);
            self.data.hash(state);
        }

        fn stream(self: Box<Self>, input: EventStream) -> BoxStream<Self::Output> {
            boxed_stream((self.spawn)(&self.data, input))
        }
    }

    from_recipe(Runner {
        data: (data, builder),
        spawn: |(data, builder), _| builder(data),
    })
}