1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145

// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// 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
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

//! IS NOT NULL expression

use std::hash::{Hash, Hasher};
use std::{any::Any, sync::Arc};

use crate::physical_expr::down_cast_any_ref;
use crate::PhysicalExpr;
use arrow::compute;
use arrow::{
    datatypes::{DataType, Schema},
    record_batch::RecordBatch,
};
use datafusion_common::Result;
use datafusion_common::ScalarValue;
use datafusion_expr::ColumnarValue;

/// IS NOT NULL expression
#[derive(Debug, Hash)]
pub struct IsNotNullExpr {
    /// The input expression
    arg: Arc<dyn PhysicalExpr>,
}

impl IsNotNullExpr {
    /// Create new not expression
    pub fn new(arg: Arc<dyn PhysicalExpr>) -> Self {
        Self { arg }
    }

    /// Get the input expression
    pub fn arg(&self) -> &Arc<dyn PhysicalExpr> {
        &self.arg
    }
}

impl std::fmt::Display for IsNotNullExpr {
    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
        write!(f, "{} IS NOT NULL", self.arg)
    }
}

impl PhysicalExpr for IsNotNullExpr {
    /// Return a reference to Any that can be used for downcasting
    fn as_any(&self) -> &dyn Any {
        self
    }

    fn data_type(&self, _input_schema: &Schema) -> Result<DataType> {
        Ok(DataType::Boolean)
    }

    fn nullable(&self, _input_schema: &Schema) -> Result<bool> {
        Ok(false)
    }

    fn evaluate(&self, batch: &RecordBatch) -> Result<ColumnarValue> {
        let arg = self.arg.evaluate(batch)?;
        match arg {
            ColumnarValue::Array(array) => Ok(ColumnarValue::Array(Arc::new(
                compute::is_not_null(array.as_ref())?,
            ))),
            ColumnarValue::Scalar(scalar) => Ok(ColumnarValue::Scalar(
                ScalarValue::Boolean(Some(!scalar.is_null())),
            )),
        }
    }

    fn children(&self) -> Vec<Arc<dyn PhysicalExpr>> {
        vec![self.arg.clone()]
    }

    fn with_new_children(
        self: Arc<Self>,
        children: Vec<Arc<dyn PhysicalExpr>>,
    ) -> Result<Arc<dyn PhysicalExpr>> {
        Ok(Arc::new(IsNotNullExpr::new(children[0].clone())))
    }

    fn dyn_hash(&self, state: &mut dyn Hasher) {
        let mut s = state;
        self.hash(&mut s);
    }
}

impl PartialEq<dyn Any> for IsNotNullExpr {
    fn eq(&self, other: &dyn Any) -> bool {
        down_cast_any_ref(other)
            .downcast_ref::<Self>()
            .map(|x| self.arg.eq(&x.arg))
            .unwrap_or(false)
    }
}
/// Create an IS NOT NULL expression
pub fn is_not_null(arg: Arc<dyn PhysicalExpr>) -> Result<Arc<dyn PhysicalExpr>> {
    Ok(Arc::new(IsNotNullExpr::new(arg)))
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::expressions::col;
    use arrow::{
        array::{BooleanArray, StringArray},
        datatypes::*,
        record_batch::RecordBatch,
    };
    use datafusion_common::cast::as_boolean_array;
    use std::sync::Arc;

    #[test]
    fn is_not_null_op() -> Result<()> {
        let schema = Schema::new(vec![Field::new("a", DataType::Utf8, true)]);
        let a = StringArray::from(vec![Some("foo"), None]);
        let expr = is_not_null(col("a", &schema)?).unwrap();
        let batch = RecordBatch::try_new(Arc::new(schema), vec![Arc::new(a)])?;

        // expression: "a is not null"
        let result = expr.evaluate(&batch)?.into_array(batch.num_rows());
        let result =
            as_boolean_array(&result).expect("failed to downcast to BooleanArray");

        let expected = &BooleanArray::from(vec![true, false]);

        assert_eq!(expected, result);

        Ok(())
    }
}