arrow_message/
helper.rs

1use crate::traits::message::ArrowMessage;
2
3pub fn make_union_fields(
4    name: impl Into<String>,
5    fields: Vec<arrow::datatypes::Field>,
6) -> arrow::datatypes::Field {
7    arrow::datatypes::Field::new(
8        name,
9        arrow::datatypes::DataType::Union(
10            arrow::datatypes::UnionFields::new(0..fields.len() as i8, fields),
11            arrow::datatypes::UnionMode::Dense,
12        ),
13        false,
14    )
15}
16
17pub fn unpack_union(
18    data: arrow::array::ArrayData,
19) -> (
20    std::collections::HashMap<String, usize>,
21    Vec<arrow::array::ArrayRef>,
22) {
23    let (fields, _, _, children) = arrow::array::UnionArray::from(data).into_parts();
24
25    let map = fields
26        .iter()
27        .map(|(id, field)| (field.name().into(), id as usize))
28        .collect::<std::collections::HashMap<String, usize>>();
29
30    (map, children)
31}
32
33pub fn extract_union_data<T: ArrowMessage>(
34    field: &str,
35    map: &std::collections::HashMap<String, usize>,
36    children: &[arrow::array::ArrayRef],
37) -> arrow::error::Result<T> {
38    use arrow::array::Array;
39
40    T::try_from_arrow(
41        children
42            .get(
43                *map.get(field)
44                    .ok_or(arrow::error::ArrowError::InvalidArgumentError(format!(
45                        "Field {} not found",
46                        field
47                    )))?,
48            )
49            .ok_or(arrow::error::ArrowError::InvalidArgumentError(format!(
50                "Field {} not found",
51                field
52            )))?
53            .into_data(),
54    )
55}
56
57pub fn get_union_fields<T: ArrowMessage>() -> arrow::error::Result<arrow::datatypes::UnionFields> {
58    match T::field("").data_type() {
59        arrow::datatypes::DataType::Union(fields, _) => Ok(fields.clone()),
60        _ => Err(arrow::error::ArrowError::InvalidArgumentError(
61            "Expected Union data type".to_string(),
62        )),
63    }
64}
65
66pub fn make_union_array(
67    union_fields: arrow::datatypes::UnionFields,
68    children: Vec<arrow::array::ArrayRef>,
69) -> Result<arrow::array::ArrayRef, arrow::error::ArrowError> {
70    arrow::array::UnionArray::try_new(
71        union_fields,
72        arrow::buffer::ScalarBuffer::from(vec![]),
73        Some(arrow::buffer::ScalarBuffer::from(vec![])),
74        children,
75    )
76    .map(|union| std::sync::Arc::new(union) as arrow::array::ArrayRef)
77}
arrow_message/helper.rs

arrow_message/
helper.rs
