pub struct StreamNotifyClose<S> { /* private fields */ }
Expand description

A Stream that wraps the values in an Option.

Whenever the wrapped stream yields an item, this stream yields that item wrapped in Some. When the inner stream ends, then this stream first yields a None item, and then this stream will also end.

Example

Using StreamNotifyClose to handle closed streams with StreamMap.

use tokio_stream::{StreamExt, StreamMap, StreamNotifyClose};

#[tokio::main]
async fn main() {
    let mut map = StreamMap::new();
    let stream = StreamNotifyClose::new(tokio_stream::iter(vec![0, 1]));
    let stream2 = StreamNotifyClose::new(tokio_stream::iter(vec![0, 1]));
    map.insert(0, stream);
    map.insert(1, stream2);
    while let Some((key, val)) = map.next().await {
        match val {
            Some(val) => println!("got {val:?} from stream {key:?}"),
            None => println!("stream {key:?} closed"),
        }
    }
}

Implementations§

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impl<S> StreamNotifyClose<S>

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pub fn new(stream: S) -> Self

Create a new StreamNotifyClose.

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pub fn into_inner(self) -> Option<S>

Get back the inner Stream.

Returns None if the stream has reached its end.

Trait Implementations§

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impl<S> Stream for StreamNotifyClose<S>where S: Stream,

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type Item = Option<<S as Stream>::Item>

Values yielded by the stream.
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fn poll_next( self: Pin<&mut Self>, cx: &mut Context<'_> ) -> Poll<Option<Self::Item>>

Attempt to pull out the next value of this stream, registering the current task for wakeup if the value is not yet available, and returning None if the stream is exhausted. Read more
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fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the stream. Read more
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impl<'__pin, S> Unpin for StreamNotifyClose<S>where __Origin<'__pin, S>: Unpin,

Auto Trait Implementations§

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impl<S> RefUnwindSafe for StreamNotifyClose<S>where S: RefUnwindSafe,

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impl<S> Send for StreamNotifyClose<S>where S: Send,

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impl<S> Sync for StreamNotifyClose<S>where S: Sync,

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impl<S> UnwindSafe for StreamNotifyClose<S>where S: UnwindSafe,

Blanket Implementations§

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impl<T> Any for Twhere T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for Twhere T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for Twhere T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for Twhere U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<St> StreamExt for Stwhere St: Stream + ?Sized,

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fn next(&mut self) -> Next<'_, Self>where Self: Unpin,

Consumes and returns the next value in the stream or None if the stream is finished. Read more
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fn try_next<T, E>(&mut self) -> TryNext<'_, Self>where Self: Stream<Item = Result<T, E>> + Unpin,

Consumes and returns the next item in the stream. If an error is encountered before the next item, the error is returned instead. Read more
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fn map<T, F>(self, f: F) -> Map<Self, F>where F: FnMut(Self::Item) -> T, Self: Sized,

Maps this stream’s items to a different type, returning a new stream of the resulting type. Read more
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fn map_while<T, F>(self, f: F) -> MapWhile<Self, F>where F: FnMut(Self::Item) -> Option<T>, Self: Sized,

Map this stream’s items to a different type for as long as determined by the provided closure. A stream of the target type will be returned, which will yield elements until the closure returns None. Read more
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fn then<F, Fut>(self, f: F) -> Then<Self, Fut, F>where F: FnMut(Self::Item) -> Fut, Fut: Future, Self: Sized,

Maps this stream’s items asynchronously to a different type, returning a new stream of the resulting type. Read more
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fn merge<U>(self, other: U) -> Merge<Self, U>where U: Stream<Item = Self::Item>, Self: Sized,

Combine two streams into one by interleaving the output of both as it is produced. Read more
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fn filter<F>(self, f: F) -> Filter<Self, F>where F: FnMut(&Self::Item) -> bool, Self: Sized,

Filters the values produced by this stream according to the provided predicate. Read more
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fn filter_map<T, F>(self, f: F) -> FilterMap<Self, F>where F: FnMut(Self::Item) -> Option<T>, Self: Sized,

Filters the values produced by this stream while simultaneously mapping them to a different type according to the provided closure. Read more
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fn fuse(self) -> Fuse<Self>where Self: Sized,

Creates a stream which ends after the first None. Read more
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fn take(self, n: usize) -> Take<Self>where Self: Sized,

Creates a new stream of at most n items of the underlying stream. Read more
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fn take_while<F>(self, f: F) -> TakeWhile<Self, F>where F: FnMut(&Self::Item) -> bool, Self: Sized,

Take elements from this stream while the provided predicate resolves to true. Read more
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fn skip(self, n: usize) -> Skip<Self>where Self: Sized,

Creates a new stream that will skip the n first items of the underlying stream. Read more
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fn skip_while<F>(self, f: F) -> SkipWhile<Self, F>where F: FnMut(&Self::Item) -> bool, Self: Sized,

Skip elements from the underlying stream while the provided predicate resolves to true. Read more
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fn all<F>(&mut self, f: F) -> AllFuture<'_, Self, F>where Self: Unpin, F: FnMut(Self::Item) -> bool,

Tests if every element of the stream matches a predicate. Read more
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fn any<F>(&mut self, f: F) -> AnyFuture<'_, Self, F>where Self: Unpin, F: FnMut(Self::Item) -> bool,

Tests if any element of the stream matches a predicate. Read more
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fn chain<U>(self, other: U) -> Chain<Self, U>where U: Stream<Item = Self::Item>, Self: Sized,

Combine two streams into one by first returning all values from the first stream then all values from the second stream. Read more
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fn fold<B, F>(self, init: B, f: F) -> FoldFuture<Self, B, F>where Self: Sized, F: FnMut(B, Self::Item) -> B,

A combinator that applies a function to every element in a stream producing a single, final value. Read more
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fn collect<T>(self) -> Collect<Self, T>where T: FromStream<Self::Item>, Self: Sized,

Drain stream pushing all emitted values into a collection. Read more
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impl<T, U> TryFrom<U> for Twhere U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.