Method add_partial_result

datafusion/physical-expr/src/expressions/case.rs:553–602

Adds a partial result array. This method adds the given array data as a partial result and updates the index mapping to indicate that the specified rows should take their values from this array. The partial results will be merged into a single array when finish() is called.

(
        &mut self,
        row_indices: &ArrayRef,
        row_values: ArrayRef,
    )

    /// to indicate that the specified rows should take their values from this array.
    /// The partial results will be merged into a single array when finish() is called.
    fn add_partial_result(
        &mut self,
        row_indices: &ArrayRef,
        row_values: ArrayRef,
    ) -> Result<()> {
        assert_or_internal_err!(
            row_indices.null_count() == 0,
            "Row indices must not contain nulls"
        );

        match &mut self.state {
            ResultState::Empty => {
                let array_index = PartialResultIndex::zero();
                let mut indices = vec![PartialResultIndex::none(); self.row_count];
                for row_ix in row_indices.as_primitive::<UInt32Type>().values().iter() {
                    indices[*row_ix as usize] = array_index;
                }

                self.state = ResultState::Partial {
                    arrays: vec![row_values],
                    indices,
                };

                Ok(())
            }
            ResultState::Partial { arrays, indices } => {
                let array_index = PartialResultIndex::try_new(arrays.len())?;

                arrays.push(row_values);

                for row_ix in row_indices.as_primitive::<UInt32Type>().values().iter() {
                    // This is check is only active for debug config because the callers of this method,
                    // `case_when_with_expr` and `case_when_no_expr`, already ensure that
                    // they only calculate a value for each row at most once.
                    #[cfg(debug_assertions)]
                    assert_or_internal_err!(
                        indices[*row_ix as usize].is_none(),
                        "Duplicate value for row {}",
                        *row_ix
                    );

                    indices[*row_ix as usize] = array_index;
                }
                Ok(())
            }
            ResultState::Complete(_) => internal_err!(
                "Cannot add a partial result when complete result is already set"
            ),
        }
    }

    /// Sets a result that applies to all rows.
    ///