vortex_scalar/
struct_.rs

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
use std::sync::Arc;

use vortex_dtype::field::Field;
use vortex_dtype::DType;
use vortex_error::{vortex_bail, vortex_err, VortexError, VortexExpect, VortexResult};

use crate::value::ScalarValue;
use crate::Scalar;

pub struct StructScalar<'a> {
    dtype: &'a DType,
    fields: Option<Arc<[ScalarValue]>>,
}

impl<'a> StructScalar<'a> {
    #[inline]
    pub fn dtype(&self) -> &'a DType {
        self.dtype
    }

    pub fn is_null(&self) -> bool {
        self.fields.is_none()
    }

    pub fn field_by_idx(&self, idx: usize) -> Option<Scalar> {
        let DType::Struct(st, _) = self.dtype() else {
            unreachable!()
        };

        self.fields
            .as_ref()
            .and_then(|fields| fields.get(idx))
            .map(|field| Scalar {
                dtype: st.dtypes()[idx].clone(),
                value: field.clone(),
            })
    }

    pub fn field(&self, name: &str) -> Option<Scalar> {
        let DType::Struct(st, _) = self.dtype() else {
            unreachable!()
        };
        st.find_name(name).and_then(|idx| self.field_by_idx(idx))
    }

    pub fn fields(&self) -> Option<&[ScalarValue]> {
        self.fields.as_deref()
    }

    pub fn cast(&self, dtype: &DType) -> VortexResult<Scalar> {
        let DType::Struct(st, _) = dtype else {
            vortex_bail!("Can only cast struct to another struct")
        };
        let DType::Struct(own_st, _) = self.dtype() else {
            unreachable!()
        };

        if st.dtypes().len() != own_st.dtypes().len() {
            vortex_bail!(
                "Cannot cast between structs with different number of fields: {} and {}",
                own_st.dtypes().len(),
                st.dtypes().len()
            );
        }

        if let Some(fs) = self.fields() {
            let fields = fs
                .iter()
                .enumerate()
                .map(|(i, f)| {
                    Scalar {
                        dtype: own_st.dtypes()[i].clone(),
                        value: f.clone(),
                    }
                    .cast(&st.dtypes()[i])
                    .map(|s| s.value)
                })
                .collect::<VortexResult<Vec<_>>>()?;
            Ok(Scalar {
                dtype: dtype.clone(),
                value: ScalarValue::List(fields.into()),
            })
        } else {
            Ok(Scalar::null(dtype.clone()))
        }
    }

    pub fn project(&self, projection: &[Field]) -> VortexResult<Scalar> {
        let struct_dtype = self
            .dtype
            .as_struct()
            .ok_or_else(|| vortex_err!("Not a struct dtype"))?;
        let projected_dtype = struct_dtype.project(projection)?;
        let new_fields = if let Some(fs) = self.fields() {
            ScalarValue::List(
                projection
                    .iter()
                    .map(|p| match p {
                        Field::Name(n) => struct_dtype
                            .find_name(n)
                            .vortex_expect("DType has been successfully projected already"),
                        Field::Index(i) => *i,
                    })
                    .map(|i| fs[i].clone())
                    .collect(),
            )
        } else {
            ScalarValue::Null
        };
        Ok(Scalar::new(
            DType::Struct(projected_dtype, self.dtype().nullability()),
            new_fields,
        ))
    }
}

impl Scalar {
    pub fn r#struct(dtype: DType, children: Vec<ScalarValue>) -> Self {
        Self {
            dtype,
            value: ScalarValue::List(children.into()),
        }
    }
}

impl<'a> TryFrom<&'a Scalar> for StructScalar<'a> {
    type Error = VortexError;

    fn try_from(value: &'a Scalar) -> Result<Self, Self::Error> {
        if !matches!(value.dtype(), DType::Struct(..)) {
            vortex_bail!("Expected struct scalar, found {}", value.dtype())
        }
        Ok(Self {
            dtype: value.dtype(),
            fields: value.value.as_list()?.cloned(),
        })
    }
}