Trait spacetimedb_commitlog::payload::txdata::Visitor

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pub trait Visitor {
    type Error: From<DecodeError>;
    type Row;

    // Required methods
    fn visit_insert<'a, R: BufReader<'a>>(
        &mut self,
        table_id: TableId,
        reader: &mut R
    ) -> Result<Self::Row, Self::Error>;
    fn visit_delete<'a, R: BufReader<'a>>(
        &mut self,
        table_id: TableId,
        reader: &mut R
    ) -> Result<Self::Row, Self::Error>;

    // Provided methods
    fn visit_truncate(&mut self, _table_id: TableId) -> Result<(), Self::Error> { ... }
    fn visit_tx_start(&mut self, _offset: u64) -> Result<(), Self::Error> { ... }
    fn visit_tx_end(&mut self) -> Result<(), Self::Error> { ... }
    fn visit_inputs(&mut self, _inputs: &Inputs) -> Result<(), Self::Error> { ... }
    fn visit_outputs(&mut self, _outputs: &Outputs) -> Result<(), Self::Error> { ... }
}

Expand description

A visitor useful to implement stateful [Decoder]s of Txdata payloads.

Required Associated Types§

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type Error: From<DecodeError>

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type Row

The type corresponding to one element in Ops::rowdata.

Required Methods§

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fn visit_insert<'a, R: BufReader<'a>>( &mut self, table_id: TableId, reader: &mut R ) -> Result<Self::Row, Self::Error>

Called for each row in each Ops of a Mutations’ inserts.

The implementation is expected to determine the appropriate schema based on the supplied TableId, and to decode the row data from the supplied BufReader.

The reader’s position is assumed to be at the start of the next row after the method returns.

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fn visit_delete<'a, R: BufReader<'a>>( &mut self, table_id: TableId, reader: &mut R ) -> Result<Self::Row, Self::Error>

Called for each row in each Ops of a Mutations’ deletes.

Similar to Self::visit_insert, but allows the visitor to determine the start of the next section in a Mutations payload.