Trait Repo 

pub trait Repo: Clone {
    type SegmentWriter: SegmentWriter + 'static;
    type SegmentReader: SegmentReader + 'static;

    // Required methods
    fn create_segment(&self, offset: u64) -> Result<Self::SegmentWriter>;
    fn open_segment_reader(&self, offset: u64) -> Result<Self::SegmentReader>;
    fn open_segment_writer(&self, offset: u64) -> Result<Self::SegmentWriter>;
    fn remove_segment(&self, offset: u64) -> Result<()>;
    fn compress_segment(&self, offset: u64) -> Result<()>;
    fn existing_offsets(&self) -> Result<Vec<u64>>;

    // Provided methods
    fn create_offset_index(
        &self,
        _offset: TxOffset,
        _cap: u64,
    ) -> Result<TxOffsetIndexMut> { ... }
    fn remove_offset_index(&self, _offset: TxOffset) -> Result<()> { ... }
    fn get_offset_index(&self, _offset: TxOffset) -> Result<TxOffsetIndex> { ... }
}

A repository of log segments.

This is mainly an internal trait to allow testing against an in-memory representation.

Required Associated Types

type SegmentWriter: SegmentWriter + 'static

The type of log segments managed by this repo, which must behave like a file.

type SegmentReader: SegmentReader + 'static

Required Methods

fn create_segment(&self, offset: u64) -> Result<Self::SegmentWriter>

Create a new segment with the minimum transaction offset offset.

This must create the segment atomically, and return io::ErrorKind::AlreadyExists if the segment already exists.

It is permissible, however, to successfully return the new segment if it is completely empty (i.e. create_segment_writer did not previously succeed in writing the segment header).

fn open_segment_reader(&self, offset: u64) -> Result<Self::SegmentReader>

Open an existing segment at the minimum transaction offset offset.

Must return io::ErrorKind::NotFound if a segment with the given offset does not exist.

The method does not guarantee that the segment is non-empty – this case will be caught by open_segment_reader.

fn open_segment_writer(&self, offset: u64) -> Result<Self::SegmentWriter>

Open an existing segment at the minimum transaction offset offset.

Must return io::ErrorKind::NotFound if a segment with the given offset does not exist.

The method does not guarantee that the segment is non-empty – this case will be caught by resume_segment_writer.

fn remove_segment(&self, offset: u64) -> Result<()>

Remove the segment at the minimum transaction offset offset.

Return io::ErrorKind::NotFound if no such segment exists.

fn compress_segment(&self, offset: u64) -> Result<()>

Compress a segment in storage, marking it as immutable.

fn existing_offsets(&self) -> Result<Vec<u64>>

Traverse all segments in this repository and return list of their offsets, sorted in ascending order.

Provided Methods

fn create_offset_index( &self, _offset: TxOffset, _cap: u64, ) -> Result<TxOffsetIndexMut>

Create TxOffsetIndexMut for the given offset or open it if already exist. The cap parameter is the maximum number of entries in the index.

fn remove_offset_index(&self, _offset: TxOffset) -> Result<()>

Remove TxOffsetIndexMut named with offset.

fn get_offset_index(&self, _offset: TxOffset) -> Result<TxOffsetIndex>

Get TxOffsetIndex for the given offset.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl<T: Repo> Repo for &T

fn remove_offset_index(&self, offset: TxOffset) -> Result<()>

Remove TxOffsetIndexMut named with offset.

fn get_offset_index(&self, offset: TxOffset) -> Result<TxOffsetIndex>

Get TxOffsetIndex for the given offset.

type SegmentWriter = <T as Repo>::SegmentWriter

type SegmentReader = <T as Repo>::SegmentReader

fn create_segment(&self, offset: u64) -> Result<Self::SegmentWriter>

fn open_segment_reader(&self, offset: u64) -> Result<Self::SegmentReader>

fn open_segment_writer(&self, offset: u64) -> Result<Self::SegmentWriter>

fn remove_segment(&self, offset: u64) -> Result<()>

fn compress_segment(&self, offset: u64) -> Result<()>

fn existing_offsets(&self) -> Result<Vec<u64>>

fn create_offset_index( &self, offset: TxOffset, cap: u64, ) -> Result<TxOffsetIndexMut>

Implementors

impl Repo for Fs

type SegmentWriter = File

type SegmentReader = CompressReader