Struct sea_streamer_file::MessageSource

pub struct MessageSource { /* private fields */ }

A high level file reader that demux messages and beacon

Implementations

impl MessageSource

pub async fn new(file_id: FileId, mode: StreamMode) -> Result<Self, FileErr>

Creates a new message source. First, the stream Header is read from the file’s beginning.

If StreamMode is Live, it will fast forward to the file’s end.

pub fn file_header(&self) -> &Header

pub async fn rewind(&mut self, target: SeqPos) -> Result<u32, FileErr>

Rewind the message stream to a coarse position. SeqNo is regarded as the N-th beacon. Returns the current location in terms of N-th beacon.

Warning: This future must not be canceled.

pub async fn seek( &mut self, stream_key: &StreamKey, shard_id: &ShardId, to: SeekTarget ) -> Result<(), FileErr>

Warning: This future must not be canceled.

pub async fn switch_to(&mut self, stype: FileSourceType) -> Result<(), FileErr>

Switch the file source type.

Warning: This future must not be canceled.

pub async fn next(&mut self) -> Result<Message, FileErr>

Read the next message.

pub fn beacon(&self) -> (u32, &[Marker])

Get the most recent Beacon and it’s index. Note that it is cleared (rather than carry-over) on each Beacon point.

Beacon index starts from 1 (don’t wary, because 0 is the header), and we have the following equation:

file offset = beacon index * beacon interval

pub fn offset(&self) -> u64

Trait Implementations

impl BeaconReader for MessageSource

type Future<'a> = Pin<Box<dyn Future<Output = Result<Beacon, FileErr>> + Send + 'a>>

fn survey(&mut self, at: NonZeroU32) -> Self::Future<'_>

fn max_beacons(&self) -> u32

Returns the max N-th Beacon

impl ByteSource for MessageSource

type Future<'a> = Pin<Box<dyn Future<Output = Result<Bytes, FileErr>> + Send + 'a>>

Too complex to unroll by hand. Let’s just box it.

fn request_bytes(&mut self, size: usize) -> Self::Future<'_>

Although this is exposed as public. Do not call this directly, this will interfere the Message Stream.