Trait ReplicationLog

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pub trait ReplicationLog {
    // Required methods
    fn append(&mut self, record: Vec<u8>) -> SyncResult<usize>;
    fn append_with_sequence(
        &mut self,
        record: Vec<u8>,
        sequence: u64,
    ) -> SyncResult<usize>;
    fn events_since(&self, index: usize) -> SyncResult<Vec<Vec<u8>>>;
    fn last_index(&self) -> SyncResult<usize>;
    fn len(&self) -> SyncResult<usize>;
    fn is_empty(&self) -> SyncResult<bool>;

    // Provided methods
    fn event_at_sequence(&self, _sequence: u64) -> SyncResult<Option<Vec<u8>>> { ... }
    fn events_page(
        &self,
        index: usize,
        max_records: usize,
        max_bytes: usize,
    ) -> SyncResult<Vec<Vec<u8>>> { ... }
    fn create_snapshot(&self) -> SyncResult<ReplicationSnapshot> { ... }
    fn restore_snapshot(
        &mut self,
        _snapshot: &ReplicationSnapshot,
    ) -> SyncResult<()> { ... }
}

Expand description

Replication log contract.

Required Methods§

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fn append(&mut self, record: Vec<u8>) -> SyncResult<usize>

Appends an unsequenced record and returns its one-based log index.

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fn append_with_sequence( &mut self, record: Vec<u8>, sequence: u64, ) -> SyncResult<usize>

Idempotently appends record at a source sequence.

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fn events_since(&self, index: usize) -> SyncResult<Vec<Vec<u8>>>

Returns payloads after the supplied zero-based log offset.

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fn last_index(&self) -> SyncResult<usize>

Returns the one-based final log index, or zero for an empty log.

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fn len(&self) -> SyncResult<usize>

Returns the number of records in the log.

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fn is_empty(&self) -> SyncResult<bool>

Reports whether the log contains no records.

Provided Methods§

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fn event_at_sequence(&self, _sequence: u64) -> SyncResult<Option<Vec<u8>>>

Returns the payload at a source sequence when sequence lookup is supported.

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fn events_page( &self, index: usize, max_records: usize, max_bytes: usize, ) -> SyncResult<Vec<Vec<u8>>>

Returns one payload page with bounded record count and payload bytes.

Compatibility providers may use the default full-read adapter. Durable providers should override this method to enforce both limits before materializing payloads. The default moves selected payloads without another deep copy, but cannot bound the allocation performed by events_since before selection.

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