Trait LogicalPageDecoder 

pub trait LogicalPageDecoder: Debug + Send {
    // Required methods
    fn wait_for_loaded(&mut self, loaded_need: u64) -> BoxFuture<'_, Result<()>>;
    fn rows_loaded(&self) -> u64;
    fn num_rows(&self) -> u64;
    fn rows_drained(&self) -> u64;
    fn drain(&mut self, num_rows: u64) -> Result<NextDecodeTask>;
    fn data_type(&self) -> &DataType;

    // Provided methods
    fn accept_child(&mut self, _child: DecoderReady) -> Result<()> { ... }
    fn rows_unloaded(&self) -> u64 { ... }
    fn rows_left(&self) -> u64 { ... }
    fn max_rows_to_drain(
        &self,
        num_rows: u64,
        _byte_budget: u64,
    ) -> Result<DrainLimit> { ... }
}

Stateful decoder for one logical page.

Required Methods

fn wait_for_loaded(&mut self, loaded_need: u64) -> BoxFuture<'_, Result<()>>

fn rows_loaded(&self) -> u64

fn num_rows(&self) -> u64

fn rows_drained(&self) -> u64

fn drain(&mut self, num_rows: u64) -> Result<NextDecodeTask>

fn data_type(&self) -> &DataType

Provided Methods

fn accept_child(&mut self, _child: DecoderReady) -> Result<()>

fn rows_unloaded(&self) -> u64

fn rows_left(&self) -> u64

fn max_rows_to_drain( &self, num_rows: u64, _byte_budget: u64, ) -> Result<DrainLimit>

Returns how many of the requested rows can be decoded into one Arrow array while keeping every i32 offset buffer within byte_budget bytes.

Most page decoders can always drain the full request and consume no budget. Decoders that build arrays with i32 offsets (Utf8 / Binary / List) may return fewer rows so that the concatenated array’s offsets stay representable, and report the budget those rows consume so callers can accumulate across pages.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors