datafusion 4.0.0

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// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
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// software distributed under the License is distributed on an
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// specific language governing permissions and limitations
// under the License.

//! Defines physical expressions that can evaluated at runtime during query execution

use std::sync::Arc;

use super::ColumnarValue;
use crate::error::{DataFusionError, Result};
use crate::physical_plan::PhysicalExpr;
use arrow::compute::kernels::sort::{SortColumn, SortOptions};
use arrow::record_batch::RecordBatch;

mod average;
#[macro_use]
mod binary;
mod case;
mod cast;
mod coercion;
mod column;
mod count;
mod in_list;
mod is_not_null;
mod is_null;
mod literal;
mod min_max;
mod negative;
mod not;
mod nullif;
mod sum;
mod try_cast;

pub use average::{avg_return_type, Avg, AvgAccumulator};
pub use binary::{binary, binary_operator_data_type, BinaryExpr};
pub use case::{case, CaseExpr};
pub use cast::{cast, cast_with_options, CastExpr};
pub use column::{col, Column};
pub use count::Count;
pub use in_list::{in_list, InListExpr};
pub use is_not_null::{is_not_null, IsNotNullExpr};
pub use is_null::{is_null, IsNullExpr};
pub use literal::{lit, Literal};
pub use min_max::{Max, Min};
pub use negative::{negative, NegativeExpr};
pub use not::{not, NotExpr};
pub use nullif::{nullif_func, SUPPORTED_NULLIF_TYPES};
pub use sum::{sum_return_type, Sum};
pub use try_cast::{try_cast, TryCastExpr};
/// returns the name of the state
pub fn format_state_name(name: &str, state_name: &str) -> String {
    format!("{}[{}]", name, state_name)
}

/// Represents Sort operation for a column in a RecordBatch
#[derive(Clone, Debug)]
pub struct PhysicalSortExpr {
    /// Physical expression representing the column to sort
    pub expr: Arc<dyn PhysicalExpr>,
    /// Option to specify how the given column should be sorted
    pub options: SortOptions,
}

impl PhysicalSortExpr {
    /// evaluate the sort expression into SortColumn that can be passed into arrow sort kernel
    pub fn evaluate_to_sort_column(&self, batch: &RecordBatch) -> Result<SortColumn> {
        let value_to_sort = self.expr.evaluate(batch)?;
        let array_to_sort = match value_to_sort {
            ColumnarValue::Array(array) => array,
            ColumnarValue::Scalar(scalar) => {
                return Err(DataFusionError::Internal(format!(
                    "Sort operation is not applicable to scalar value {}",
                    scalar
                )));
            }
        };
        Ok(SortColumn {
            values: array_to_sort,
            options: Some(self.options),
        })
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::{error::Result, physical_plan::AggregateExpr, scalar::ScalarValue};

    /// macro to perform an aggregation and verify the result.
    #[macro_export]
    macro_rules! generic_test_op {
        ($ARRAY:expr, $DATATYPE:expr, $OP:ident, $EXPECTED:expr, $EXPECTED_DATATYPE:expr) => {{
            let schema = Schema::new(vec![Field::new("a", $DATATYPE, false)]);

            let batch = RecordBatch::try_new(Arc::new(schema.clone()), vec![$ARRAY])?;

            let agg =
                Arc::new(<$OP>::new(col("a"), "bla".to_string(), $EXPECTED_DATATYPE));
            let actual = aggregate(&batch, agg)?;
            let expected = ScalarValue::from($EXPECTED);

            assert_eq!(expected, actual);

            Ok(())
        }};
    }

    pub fn aggregate(
        batch: &RecordBatch,
        agg: Arc<dyn AggregateExpr>,
    ) -> Result<ScalarValue> {
        let mut accum = agg.create_accumulator()?;
        let expr = agg.expressions();
        let values = expr
            .iter()
            .map(|e| e.evaluate(batch))
            .map(|r| r.map(|v| v.into_array(batch.num_rows())))
            .collect::<Result<Vec<_>>>()?;
        accum.update_batch(&values)?;
        accum.evaluate()
    }
}