73 lines
1.4 KiB
Rust
73 lines
1.4 KiB
Rust
use err::Error;
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use futures_core::Stream;
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use futures_util::StreamExt;
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use std::pin::Pin;
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use std::task::{Context, Poll};
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pub struct SCC<S>
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where
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S: Stream,
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{
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inp: S,
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errored: bool,
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completed: bool,
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}
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impl<S> SCC<S>
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where
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S: Stream,
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{
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pub fn new(inp: S) -> Self {
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Self {
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inp,
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errored: false,
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completed: false,
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}
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}
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}
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impl<S, I> Stream for SCC<S>
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where
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S: Stream<Item = Result<I, Error>> + Unpin,
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{
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type Item = <S as Stream>::Item;
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fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>> {
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use Poll::*;
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if self.completed {
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panic!("poll_next on completed");
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} else if self.errored {
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self.completed = true;
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Ready(None)
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} else {
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match self.inp.poll_next_unpin(cx) {
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Ready(Some(Ok(k))) => Ready(Some(Ok(k))),
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Ready(Some(Err(e))) => {
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self.errored = true;
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Ready(Some(Err(e)))
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}
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Ready(None) => {
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self.completed = true;
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Ready(None)
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}
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Pending => Pending,
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}
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}
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}
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}
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pub trait IntoSCC<S>
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where
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S: Stream,
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{
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fn into_scc(self) -> SCC<S>;
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}
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impl<S> IntoSCC<S> for S
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where
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S: Stream,
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{
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fn into_scc(self) -> SCC<S> {
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SCC::new(self)
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}
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}
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