Struct MessageReader 

struct MessageReader<R> {
    reader: R,
    buf: Vec<u8>,
}

A low-level construct that reads Message::Messages from a reader while re-using a buffer for metadata. This is composed into StreamReader.

Fields

reader: R

buf: Vec<u8>

Implementations

impl<R: Read> MessageReader<R>

fn new(reader: R) -> Self

fn maybe_next( &mut self, ) -> Result<Option<(Message<'_>, MutableBuffer)>, ArrowError>

Reads the entire next message from the underlying reader which includes the metadata length, the metadata, and the body.

Returns

• Ok(None) if the the reader signals the end of stream with EOF on the first read
• Err(_) if the reader returns an error other than on the first read, or if the metadata length is invalid
• Ok(Some(_)) with the Message and buffer containiner the body bytes otherwise.

fn inner_mut(&mut self) -> &mut R

Get a mutable reference to the underlying reader.

fn inner(&self) -> &R

Get an immutable reference to the underlying reader.

pub fn read_meta_len(&mut self) -> Result<Option<usize>, ArrowError>

Read the metadata length for the next message from the underlying stream.

Returns

• Ok(None) if the the reader signals the end of stream with EOF on the first read
• Err(_) if the reader returns an error other than on the first read, or if the metadata length is less than 0.
• Ok(Some(_)) with the length otherwise.