Struct FrameWriter 

pub struct FrameWriter { /* private fields */ }

Sends messages as frames without allocating per message: it keeps the buffers a message is written into, so once they have grown to the biggest message, a send only writes. Each frame (its length, then its body) goes out in one write_all, then the writer is flushed.

• FrameWriter::send_packed sends the packed frame layout (crate::frame): allocation-free once warm for messages whose fields are plain values, strings, lists and records.
• FrameWriter::send sends the named binary form (SDAT): also allocation-free once warm, except where a field writes through a crate::Stream, which builds its body apart.

use substrate_data::io::{FrameWriter, read_frame};

let mut sender = FrameWriter::new();
let mut pipe = Vec::new();
sender.send(&mut pipe, &"hello".to_string())?;
sender.send(&mut pipe, &"again".to_string())?;
assert_eq!(read_frame::<String>(&mut pipe.as_slice())?.as_deref(), Some("hello"));

Implementations

impl FrameWriter

pub fn new() -> FrameWriter

A writer with nothing grown yet: the first sends allocate.

pub fn send<T>(&mut self, w: &mut impl Write, message: &T) -> Result<(), Error>

where T: Schema,

Sends message in the named binary form, and flushes.

Errors

The writer’s I/O error; io::ErrorKind::InvalidInput for a frame over super::MAX_FRAME (nothing is written).

pub fn send_packed<T>( &mut self, w: &mut impl Write, message: &T, ) -> Result<(), Error>

where T: Schema,

Sends message in the packed frame layout, and flushes.

Errors

The writer’s I/O error; io::ErrorKind::InvalidInput for a frame over super::MAX_FRAME (nothing is written).

Trait Implementations

impl Debug for FrameWriter

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

Formats the value using the given formatter.

impl Default for FrameWriter

fn default() -> FrameWriter

Returns the “default value” for a type.