Struct LineBuffer 

pub(super) struct LineBuffer {
    pub(super) stdout: BytesMut,
    stderr: BytesMut,
}

Collects the output of both pipes into whole lines for journald, which writes one entry per line.

A read chunk may end anywhere, in the middle of a line, between “\r” and “\n” or inside a multi byte character. Keeping the incomplete tail until the next chunk of the same pipe arrives avoids split lines and garbled characters. A line which grows beyond LineBuffer::MAX_LINE is written as a partial one, cut at a character boundary, and so is a line which waits too long for its ending, see LineBuffer::flush.

Fields

stdout: BytesMut

stderr: BytesMut

Implementations

impl LineBuffer

pub(super) const MAX_LINE: usize

Longer lines get written as partial entries.

fn tail(&mut self, pipe: Pipe) -> &mut BytesMut

pub(super) fn has_pending(&self, pipe: Pipe) -> bool

Whether a line of the pipe waits for its ending.

pub(super) fn push<'a>(&mut self, pipe: Pipe, bytes: &'a [u8]) -> Vec<Line<'a>>

Add a chunk and return the lines it completes. The whole lines of the chunk borrow it, only the end of a line which started in an earlier chunk and the start of one which continues in a later one get copied into the buffer of the pipe.

fn cut_long(tail: &mut BytesMut) -> Option<Line<'static>>

Cut a line which grew too long without its ending, see LineBuffer::cut, and release the buffer once empty.

fn cut(tail: &mut BytesMut) -> Line<'static>

Cut the tail at a point which keeps an unfinished multi byte character and a “\r” waiting for its “\n” in the buffer. Invalid bytes are not held back, they would stay in front forever.

fn complete_len(bytes: &[u8]) -> usize

The length of the bytes without the unfinished multi byte character they end with, if any. Only the last character matters, which starts within the last three bytes if it is unfinished, an invalid byte in front of it does not.

fn shrink(tail: &mut BytesMut)

A line longer than a read chunk leaves a large buffer behind, release it once drained. An idle container keeps at most a chunk of it.

pub(super) fn flush(&mut self, pipe: Pipe) -> Vec<Line<'static>>

Return the line which waits for its ending as a partial one. The output paused, a prompt or progress output without a newline would otherwise stay invisible.

pub(super) fn finish(&mut self, pipe: Pipe) -> Vec<Line<'static>>

The output of the pipe ended, return the line which still waits for its ending as a partial one.

Trait Implementations

impl Debug for LineBuffer

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

Formats the value using the given formatter.

impl Default for LineBuffer

fn default() -> Self

Returns the “default value” for a type.