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".

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