Struct futures::stream::Peekable
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[src]
#[must_use = "streams do nothing unless polled"]pub struct Peekable<S> where
S: Stream, { /* fields omitted */ }
A Stream that implements a peek method.
The peek method can be used to retrieve a reference
to the next Stream::Item if available. A subsequent
call to poll will return the owned item.
Methods
impl<S> Peekable<S> where
S: Stream, [src]
S: Stream,
pub fn peek(
&mut self,
cx: &mut Context
) -> Result<Async<Option<&<S as Stream>::Item>>, <S as Stream>::Error>[src]
&mut self,
cx: &mut Context
) -> Result<Async<Option<&<S as Stream>::Item>>, <S as Stream>::Error>
Peek retrieves a reference to the next item in the stream.
This method polls the underlying stream and return either a reference to the next item if the stream is ready or passes through any errors.
Trait Implementations
impl<S> Debug for Peekable<S> where
S: Debug + Stream,
<S as Stream>::Item: Debug, [src]
S: Debug + Stream,
<S as Stream>::Item: Debug,
fn fmt(&self, __arg_0: &mut Formatter) -> Result<(), Error>[src]
Formats the value using the given formatter. Read more
impl<S> Sink for Peekable<S> where
S: Sink + Stream, [src]
S: Sink + Stream,
type SinkItem = <S as Sink>::SinkItem
The type of value that the sink accepts.
type SinkError = <S as Sink>::SinkError
The type of value produced by the sink when an error occurs.
fn poll_ready(
&mut self,
cx: &mut Context
) -> Result<Async<()>, <Peekable<S> as Sink>::SinkError>[src]
&mut self,
cx: &mut Context
) -> Result<Async<()>, <Peekable<S> as Sink>::SinkError>
Attempts to prepare the Sink to receive a value. Read more
fn start_send(
&mut self,
item: <Peekable<S> as Sink>::SinkItem
) -> Result<(), <Peekable<S> as Sink>::SinkError>[src]
&mut self,
item: <Peekable<S> as Sink>::SinkItem
) -> Result<(), <Peekable<S> as Sink>::SinkError>
Begin the process of sending a value to the sink. Each call to this function must be proceeded by a successful call to poll_ready which returned Ok(Async::Ready(())). Read more
fn poll_flush(
&mut self,
cx: &mut Context
) -> Result<Async<()>, <Peekable<S> as Sink>::SinkError>[src]
&mut self,
cx: &mut Context
) -> Result<Async<()>, <Peekable<S> as Sink>::SinkError>
Flush any remaining output from this sink. Read more
fn poll_close(
&mut self,
cx: &mut Context
) -> Result<Async<()>, <Peekable<S> as Sink>::SinkError>[src]
&mut self,
cx: &mut Context
) -> Result<Async<()>, <Peekable<S> as Sink>::SinkError>
Flush any remaining output and close this sink, if necessary. Read more
impl<S> Stream for Peekable<S> where
S: Stream, [src]
S: Stream,
type Item = <S as Stream>::Item
Values yielded by the stream.
type Error = <S as Stream>::Error
Errors yielded by the stream.
fn poll_next(
&mut self,
cx: &mut Context
) -> Result<Async<Option<<Peekable<S> as Stream>::Item>>, <Peekable<S> as Stream>::Error>[src]
&mut self,
cx: &mut Context
) -> Result<Async<Option<<Peekable<S> as Stream>::Item>>, <Peekable<S> as Stream>::Error>
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