polars-mem-engine 0.54.4

In memory engine of the Polars project.
Documentation 
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use super::*;

pub struct ProjectionSimple {
    pub(crate) input: Box<dyn Executor>,
    pub(crate) columns: SchemaRef,
}

impl ProjectionSimple {
    fn execute_impl(&mut self, df: DataFrame, columns: &[PlSmallStr]) -> PolarsResult<DataFrame> {
        // No duplicate check as that an invariant of this node.
        unsafe { df.select_unchecked(columns) }
    }
}

impl Executor for ProjectionSimple {
    fn execute(&mut self, state: &mut ExecutionState) -> PolarsResult<DataFrame> {
        state.should_stop()?;
        let columns = self.columns.iter_names_cloned().collect::<Vec<_>>();

        let profile_name = if state.has_node_timer() {
            let name = comma_delimited("simple-projection".to_string(), columns.as_slice());
            Cow::Owned(name)
        } else {
            Cow::Borrowed("")
        };
        let df = self.input.execute(state)?;

        if state.has_node_timer() {
            state.record(|| self.execute_impl(df, columns.as_slice()), profile_name)
        } else {
            self.execute_impl(df, columns.as_slice())
        }
    }
}