Function create_segment_writer

crates/commitlog/src/repo/mod.rs:231–261

Create a new segment [`Writer`] with `offset`. Immediately attempts to write the segment header with the supplied `log_format_version`. If the segment already exists, [`io::ErrorKind::AlreadyExists`] is returned.

(
    repo: &R,
    opts: Options,
    epoch: u64,
    offset: u64,
)

///
/// If the segment already exists, [`io::ErrorKind::AlreadyExists`] is returned.
pub fn create_segment_writer<R: Repo>(
    repo: &R,
    opts: Options,
    epoch: u64,
    offset: u64,
) -> io::Result<Writer<R::SegmentWriter>> {
    let mut storage = repo.create_segment(
        offset,
        Header {
            log_format_version: opts.log_format_version,
            checksum_algorithm: Commit::CHECKSUM_ALGORITHM,
        },
    )?;
    // Ensure we have enough space for this segment.
    fallocate(&mut storage, &opts)?;

    Ok(Writer {
        commit: Commit {
            min_tx_offset: offset,
            n: 0,
            records: Vec::new(),
            epoch,
        },
        inner: io::BufWriter::with_capacity(opts.write_buffer_size, storage),

        min_tx_offset: offset,
        bytes_written: Header::LEN as u64,

        offset_index_head: create_offset_index_writer(repo, offset, opts),
    })
}

/// Outcome of [resume_segment_writer].
pub enum ResumedSegment<W: io::Write> {