datatypes/types/
list_type.rs

1// Copyright 2023 Greptime Team
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15use std::sync::Arc;
16
17use arrow::datatypes::{DataType as ArrowDataType, Field};
18use serde::{Deserialize, Serialize};
19
20use crate::data_type::{ConcreteDataType, DataType};
21use crate::type_id::LogicalTypeId;
22use crate::value::{ListValue, Value};
23use crate::vectors::{ListVectorBuilder, MutableVector};
24
25/// Used to represent the List datatype.
26#[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, Serialize, Deserialize)]
27pub struct ListType {
28    /// The type of List's item.
29    item_type: Arc<ConcreteDataType>,
30}
31
32impl Default for ListType {
33    fn default() -> Self {
34        ListType::new(Arc::new(ConcreteDataType::null_datatype()))
35    }
36}
37
38impl ListType {
39    /// Create a new `ListType` whose item's data type is `item_type`.
40    pub fn new(item_type: Arc<ConcreteDataType>) -> Self {
41        ListType { item_type }
42    }
43
44    /// Returns the item data type.
45    #[inline]
46    pub fn item_type(&self) -> &ConcreteDataType {
47        &self.item_type
48    }
49}
50
51impl DataType for ListType {
52    fn name(&self) -> String {
53        format!("List<{}>", self.item_type.name())
54    }
55
56    fn logical_type_id(&self) -> LogicalTypeId {
57        LogicalTypeId::List
58    }
59
60    fn default_value(&self) -> Value {
61        Value::List(ListValue::new(vec![], self.item_type.clone()))
62    }
63
64    fn as_arrow_type(&self) -> ArrowDataType {
65        let field = Arc::new(Field::new(
66            Field::LIST_FIELD_DEFAULT_NAME,
67            self.item_type.as_arrow_type(),
68            true,
69        ));
70        ArrowDataType::List(field)
71    }
72
73    fn create_mutable_vector(&self, capacity: usize) -> Box<dyn MutableVector> {
74        Box::new(ListVectorBuilder::with_type_capacity(
75            self.item_type.clone(),
76            capacity,
77        ))
78    }
79
80    fn try_cast(&self, from: Value) -> Option<Value> {
81        match from {
82            Value::List(v) => Some(Value::List(v)),
83            _ => None,
84        }
85    }
86}
87
88#[cfg(test)]
89mod tests {
90    use super::*;
91    use crate::value::ListValue;
92
93    #[test]
94    fn test_list_type() {
95        let t = ListType::new(Arc::new(ConcreteDataType::boolean_datatype()));
96        assert_eq!("List<Boolean>", t.name());
97        assert_eq!(LogicalTypeId::List, t.logical_type_id());
98        assert_eq!(
99            Value::List(ListValue::new(
100                vec![],
101                Arc::new(ConcreteDataType::boolean_datatype())
102            )),
103            t.default_value()
104        );
105        assert_eq!(
106            ArrowDataType::List(Arc::new(Field::new("item", ArrowDataType::Boolean, true))),
107            t.as_arrow_type()
108        );
109        assert_eq!(ConcreteDataType::boolean_datatype(), *t.item_type());
110    }
111}
datatypes/types/list_type.rs

datatypes/types/
list_type.rs
