Trait ProjectionStreamHandler 

pub trait ProjectionStreamHandler {
    // Required methods
    fn project_stream(
        &mut self,
        stream: SchemaValueStream,
        item_plan: Option<ProjectionPlan>,
    ) -> Result<SchemaValueStream, String>;
    fn discard_stream(&mut self, stream: SchemaValueStream);
}

Runtime-independent hooks needed while applying a projection. Streams are affine, so the evaluator transfers each retained stream to project_stream and every stream below a discarded value to discard_stream. On error, project_stream must dispose the stream it consumed.

Required Methods

fn project_stream( &mut self, stream: SchemaValueStream, item_plan: Option<ProjectionPlan>, ) -> Result<SchemaValueStream, String>

fn discard_stream(&mut self, stream: SchemaValueStream)

Dyn Compatibility

This trait is dyn compatible.

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

Implementors