Struct FrameReader 

pub struct FrameReader { /* private fields */ }

Reads frames into a buffer it keeps, so a stream of messages costs no allocation per frame once the buffer has grown to the biggest. The end rules are those of super::read_frame_bytes: a clean end only between frames; a stream cut inside a length or a frame is an error.

use substrate_data::io::{FrameReader, write_frame};

let mut pipe = Vec::new();
write_frame(&mut pipe, &7_u32)?;
write_frame(&mut pipe, &8_u32)?;
let (mut r, mut frames) = (pipe.as_slice(), FrameReader::new());
assert_eq!(frames.read::<u32>(&mut r)?, Some(7));
assert_eq!(frames.read::<u32>(&mut r)?, Some(8));
assert_eq!(frames.read::<u32>(&mut r)?, None);

Implementations

impl FrameReader

pub fn new() -> Self

A reader with an empty buffer.

pub fn read_bytes(&mut self, r: &mut impl Read) -> Result<Option<&[u8]>>

The next frame’s bytes, valid until the next read; None where the stream ends between frames. The buffer grows as bytes arrive, never by a length the peer merely claims.

Errors

The reader’s I/O error; io::ErrorKind::UnexpectedEof when the stream ends inside a length or a frame; io::ErrorKind::InvalidData for a length over super::MAX_FRAME.

pub fn read<T: Schema>(&mut self, r: &mut impl Read) -> Result<Option<T>>

The next message; None where the stream ends between frames.

Errors

The reader’s I/O error, or io::ErrorKind::InvalidData for a frame that isn’t a T.

Trait Implementations

impl Debug for FrameReader

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

Formats the value using the given formatter.

impl Default for FrameReader

fn default() -> Self

Returns the “default value” for a type.