Struct StreamWithFinalizationCallbacks

pub struct StreamWithFinalizationCallbacks<S, FComplete, FCancel>
where
    S: Stream,
    FComplete: FnOnce(),
    FCancel: FnOnce(),
{ /* private fields */ }

A Stream wrapper that can call two different closures:

1. complete_cb: fired exactly once when the inner stream returns None.
2. cancel_cb: fired exactly once if the wrapper is dropped before seeing None.

Internally, we keep each closure as an Option<…> so we can take() it and invoke it just one time.

Implementations

impl<S, FComplete, FCancel> StreamWithFinalizationCallbacks<S, FComplete, FCancel>

where S: Stream, FComplete: FnOnce(), FCancel: FnOnce(),

pub fn new(inner: S, complete_cb: FComplete, cancel_cb: FCancel) -> Self

Construct a new wrapper that:

• calls complete_cb once when inner.poll_next() returns Ready(None), and
• calls cancel_cb if the wrapper is dropped before seeing None.

If you don’t care about cancellations, pass in something like || {} for cancel_cb.

Trait Implementations

impl<S, FComplete, FCancel> Drop for StreamWithFinalizationCallbacks<S, FComplete, FCancel>

where S: Stream, FComplete: FnOnce(), FCancel: FnOnce(),

fn drop(&mut self)

Executes the destructor for this type.

impl<S, FComplete, FCancel, T> Stream for StreamWithFinalizationCallbacks<S, FComplete, FCancel>

where S: Stream<Item = T> + Unpin, FComplete: FnOnce(), FCancel: FnOnce(),

type Item = T

Values yielded by the stream.

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.

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the stream.