arrow_schema/extension/canonical/
bool8.rs

1// Licensed to the Apache Software Foundation (ASF) under one
2// or more contributor license agreements.  See the NOTICE file
3// distributed with this work for additional information
4// regarding copyright ownership.  The ASF licenses this file
5// to you under the Apache License, Version 2.0 (the
6// "License"); you may not use this file except in compliance
7// with the License.  You may obtain a copy of the License at
8//
9//   http://www.apache.org/licenses/LICENSE-2.0
10//
11// Unless required by applicable law or agreed to in writing,
12// software distributed under the License is distributed on an
13// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
14// KIND, either express or implied.  See the License for the
15// specific language governing permissions and limitations
16// under the License.
17
18//! 8-bit Boolean
19//!
20//! <https://arrow.apache.org/docs/format/CanonicalExtensions.html#bit-boolean>
21
22use crate::{extension::ExtensionType, ArrowError, DataType};
23
24/// The extension type for `8-bit Boolean`.
25///
26/// Extension name: `arrow.bool8`.
27///
28/// The storage type of the extension is `Int8` where:
29/// - false is denoted by the value 0.
30/// - true can be specified using any non-zero value. Preferably 1.
31///
32/// <https://arrow.apache.org/docs/format/CanonicalExtensions.html#bit-boolean>
33#[derive(Debug, Default, Clone, Copy, PartialEq)]
34pub struct Bool8;
35
36impl ExtensionType for Bool8 {
37    const NAME: &'static str = "arrow.bool8";
38
39    type Metadata = &'static str;
40
41    fn metadata(&self) -> &Self::Metadata {
42        &""
43    }
44
45    fn serialize_metadata(&self) -> Option<String> {
46        Some(String::default())
47    }
48
49    fn deserialize_metadata(metadata: Option<&str>) -> Result<Self::Metadata, ArrowError> {
50        if metadata.is_some_and(str::is_empty) {
51            Ok("")
52        } else {
53            Err(ArrowError::InvalidArgumentError(
54                "Bool8 extension type expects an empty string as metadata".to_owned(),
55            ))
56        }
57    }
58
59    fn supports_data_type(&self, data_type: &DataType) -> Result<(), ArrowError> {
60        match data_type {
61            DataType::Int8 => Ok(()),
62            data_type => Err(ArrowError::InvalidArgumentError(format!(
63                "Bool8 data type mismatch, expected Int8, found {data_type}"
64            ))),
65        }
66    }
67
68    fn try_new(data_type: &DataType, _metadata: Self::Metadata) -> Result<Self, ArrowError> {
69        Self.supports_data_type(data_type).map(|_| Self)
70    }
71}
72
73#[cfg(test)]
74mod tests {
75    #[cfg(feature = "canonical_extension_types")]
76    use crate::extension::CanonicalExtensionType;
77    use crate::{
78        extension::{EXTENSION_TYPE_METADATA_KEY, EXTENSION_TYPE_NAME_KEY},
79        Field,
80    };
81
82    use super::*;
83
84    #[test]
85    fn valid() -> Result<(), ArrowError> {
86        let mut field = Field::new("", DataType::Int8, false);
87        field.try_with_extension_type(Bool8)?;
88        field.try_extension_type::<Bool8>()?;
89        #[cfg(feature = "canonical_extension_types")]
90        assert_eq!(
91            field.try_canonical_extension_type()?,
92            CanonicalExtensionType::Bool8(Bool8)
93        );
94
95        Ok(())
96    }
97
98    #[test]
99    #[should_panic(expected = "Field extension type name missing")]
100    fn missing_name() {
101        let field = Field::new("", DataType::Int8, false).with_metadata(
102            [(EXTENSION_TYPE_METADATA_KEY.to_owned(), "".to_owned())]
103                .into_iter()
104                .collect(),
105        );
106        field.extension_type::<Bool8>();
107    }
108
109    #[test]
110    #[should_panic(expected = "expected Int8, found Boolean")]
111    fn invalid_type() {
112        Field::new("", DataType::Boolean, false).with_extension_type(Bool8);
113    }
114
115    #[test]
116    #[should_panic(expected = "Bool8 extension type expects an empty string as metadata")]
117    fn missing_metadata() {
118        let field = Field::new("", DataType::Int8, false).with_metadata(
119            [(EXTENSION_TYPE_NAME_KEY.to_owned(), Bool8::NAME.to_owned())]
120                .into_iter()
121                .collect(),
122        );
123        field.extension_type::<Bool8>();
124    }
125
126    #[test]
127    #[should_panic(expected = "Bool8 extension type expects an empty string as metadata")]
128    fn invalid_metadata() {
129        let field = Field::new("", DataType::Int8, false).with_metadata(
130            [
131                (EXTENSION_TYPE_NAME_KEY.to_owned(), Bool8::NAME.to_owned()),
132                (
133                    EXTENSION_TYPE_METADATA_KEY.to_owned(),
134                    "non-empty".to_owned(),
135                ),
136            ]
137            .into_iter()
138            .collect(),
139        );
140        field.extension_type::<Bool8>();
141    }
142}
arrow_schema/extension/canonical/bool8.rs

arrow_schema/extension/canonical/
bool8.rs
