Struct tokio_util::codec::Framed

pub struct Framed<T, U> { /* private fields */ }

Available on crate feature codec only.

A unified Stream and Sink interface to an underlying I/O object, using the Encoder and Decoder traits to encode and decode frames.

You can create a Framed instance by using the Decoder::framed adapter, or by using the new function seen below.

Cancellation safety

• futures_util::sink::SinkExt::send: if send is used as the event in a tokio::select! statement and some other branch completes first, then it is guaranteed that the message was not sent, but the message itself is lost.
• tokio_stream::StreamExt::next: This method is cancel safe. The returned future only holds onto a reference to the underlying stream, so dropping it will never lose a value.

Implementations

impl<T, U> Framed<T, U>

where T: AsyncRead + AsyncWrite,

pub fn new(inner: T, codec: U) -> Framed<T, U>

Provides a Stream and Sink interface for reading and writing to this I/O object, using Decoder and Encoder to read and write the raw data.

Raw I/O objects work with byte sequences, but higher-level code usually wants to batch these into meaningful chunks, called “frames”. This method layers framing on top of an I/O object, by using the codec traits to handle encoding and decoding of messages frames. Note that the incoming and outgoing frame types may be distinct.

This function returns a single object that is both Stream and Sink; grouping this into a single object is often useful for layering things like gzip or TLS, which require both read and write access to the underlying object.

If you want to work more directly with the streams and sink, consider calling split on the Framed returned by this method, which will break them into separate objects, allowing them to interact more easily.

Note that, for some byte sources, the stream can be resumed after an EOF by reading from it, even after it has returned None. Repeated attempts to do so, without new data available, continue to return None without creating more (closing) frames.

pub fn with_capacity(inner: T, codec: U, capacity: usize) -> Framed<T, U>

Provides a Stream and Sink interface for reading and writing to this I/O object, using Decoder and Encoder to read and write the raw data, with a specific read buffer initial capacity.

Raw I/O objects work with byte sequences, but higher-level code usually wants to batch these into meaningful chunks, called “frames”. This method layers framing on top of an I/O object, by using the codec traits to handle encoding and decoding of messages frames. Note that the incoming and outgoing frame types may be distinct.

This function returns a single object that is both Stream and Sink; grouping this into a single object is often useful for layering things like gzip or TLS, which require both read and write access to the underlying object.

If you want to work more directly with the streams and sink, consider calling split on the Framed returned by this method, which will break them into separate objects, allowing them to interact more easily.

impl<T, U> Framed<T, U>

pub fn from_parts(parts: FramedParts<T, U>) -> Framed<T, U>

Provides a Stream and Sink interface for reading and writing to this I/O object, using Decoder and Encoder to read and write the raw data.

Raw I/O objects work with byte sequences, but higher-level code usually wants to batch these into meaningful chunks, called “frames”. This method layers framing on top of an I/O object, by using the Codec traits to handle encoding and decoding of messages frames. Note that the incoming and outgoing frame types may be distinct.

This function returns a single object that is both Stream and Sink; grouping this into a single object is often useful for layering things like gzip or TLS, which require both read and write access to the underlying object.

This objects takes a stream and a readbuffer and a writebuffer. These field can be obtained from an existing Framed with the into_parts method.

If you want to work more directly with the streams and sink, consider calling split on the Framed returned by this method, which will break them into separate objects, allowing them to interact more easily.

pub fn get_ref(&self) -> &T

Returns a reference to the underlying I/O stream wrapped by Framed.

Note that care should be taken to not tamper with the underlying stream of data coming in as it may corrupt the stream of frames otherwise being worked with.

pub fn get_mut(&mut self) -> &mut T

Returns a mutable reference to the underlying I/O stream wrapped by Framed.

Note that care should be taken to not tamper with the underlying stream of data coming in as it may corrupt the stream of frames otherwise being worked with.

pub fn get_pin_mut(self: Pin<&mut Self>) -> Pin<&mut T>

Returns a pinned mutable reference to the underlying I/O stream wrapped by Framed.

Note that care should be taken to not tamper with the underlying stream of data coming in as it may corrupt the stream of frames otherwise being worked with.

pub fn codec(&self) -> &U

Returns a reference to the underlying codec wrapped by Framed.

Note that care should be taken to not tamper with the underlying codec as it may corrupt the stream of frames otherwise being worked with.

pub fn codec_mut(&mut self) -> &mut U

Returns a mutable reference to the underlying codec wrapped by Framed.

Note that care should be taken to not tamper with the underlying codec as it may corrupt the stream of frames otherwise being worked with.

pub fn map_codec<C, F>(self, map: F) -> Framed<T, C>

where F: FnOnce(U) -> C,

Maps the codec U to C, preserving the read and write buffers wrapped by Framed.

Note that care should be taken to not tamper with the underlying codec as it may corrupt the stream of frames otherwise being worked with.

pub fn codec_pin_mut(self: Pin<&mut Self>) -> &mut U

Returns a mutable reference to the underlying codec wrapped by Framed.

Note that care should be taken to not tamper with the underlying codec as it may corrupt the stream of frames otherwise being worked with.

pub fn read_buffer(&self) -> &BytesMut

Returns a reference to the read buffer.

pub fn read_buffer_mut(&mut self) -> &mut BytesMut

Returns a mutable reference to the read buffer.

pub fn write_buffer(&self) -> &BytesMut

Returns a reference to the write buffer.

pub fn write_buffer_mut(&mut self) -> &mut BytesMut

Returns a mutable reference to the write buffer.

pub fn backpressure_boundary(&self) -> usize

Returns backpressure boundary

pub fn set_backpressure_boundary(&mut self, boundary: usize)

Updates backpressure boundary

pub fn into_inner(self) -> T

Consumes the Framed, returning its underlying I/O stream.

Note that care should be taken to not tamper with the underlying stream of data coming in as it may corrupt the stream of frames otherwise being worked with.

pub fn into_parts(self) -> FramedParts<T, U>

Consumes the Framed, returning its underlying I/O stream, the buffer with unprocessed data, and the codec.

Note that care should be taken to not tamper with the underlying stream of data coming in as it may corrupt the stream of frames otherwise being worked with.

Trait Implementations

impl<T, U> Debug for Framed<T, U>

where T: Debug, U: Debug,

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T, I, U> Sink<I> for Framed<T, U>

where T: AsyncWrite, U: Encoder<I>, U::Error: From<Error>,

type Error = <U as Encoder<I>>::Error

The type of value produced by the sink when an error occurs.

fn poll_ready( self: Pin<&mut Self>, cx: &mut Context<'_>, ) -> Poll<Result<(), Self::Error>>

Attempts to prepare the Sink to receive a value.

fn start_send(self: Pin<&mut Self>, item: I) -> Result<(), Self::Error>

Begin the process of sending a value to the sink. Each call to this function must be preceded by a successful call to poll_ready which returned Poll::Ready(Ok(())).

fn poll_flush( self: Pin<&mut Self>, cx: &mut Context<'_>, ) -> Poll<Result<(), Self::Error>>

Flush any remaining output from this sink.

fn poll_close( self: Pin<&mut Self>, cx: &mut Context<'_>, ) -> Poll<Result<(), Self::Error>>

Flush any remaining output and close this sink, if necessary.

impl<T, U> Stream for Framed<T, U>

where T: AsyncRead, U: Decoder,

type Item = Result<<U as Decoder>::Item, <U as Decoder>::Error>

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.

impl<'__pin, T, U> Unpin for Framed<T, U>

where __Origin<'__pin, T, U>: Unpin,