Function add_offset_to_expr

datafusion/physical-expr/src/physical_expr.rs:37–51

Adds the `offset` value to `Column` indices inside `expr`. This function is generally used during the update of the right table schema in join operations.

(
    expr: Arc<dyn PhysicalExpr>,
    offset: isize,
)

/// Adds the `offset` value to `Column` indices inside `expr`. This function is
/// generally used during the update of the right table schema in join operations.
pub fn add_offset_to_expr(
    expr: Arc<dyn PhysicalExpr>,
    offset: isize,
) -> Result<Arc<dyn PhysicalExpr>> {
    expr.transform_down(|e| match e.downcast_ref::<Column>() {
        Some(col) => {
            let Some(idx) = col.index().checked_add_signed(offset) else {
                return plan_err!("Column index overflow");
            };
            Ok(Transformed::yes(Arc::new(Column::new(col.name(), idx))))
        }
        None => Ok(Transformed::no(e)),
    })
    .data()
}

/// This function is similar to the `contains` method of `Vec`. It finds
/// whether `expr` is among `physical_exprs`.