serde_arrow 0.14.0

Convert sequences of Rust objects to Arrow arrays and back again
Documentation 
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
146

use std::collections::{BTreeMap, HashMap};

use marrow::{
    array::{Array, MapArray},
    datatypes::{FieldMeta, MapMeta},
};
use serde::{Serialize, Serializer};

use crate::internal::{
    error::{prepend, set_default, Context, ContextSupport, Error, Result},
    serialization::utils::impl_serializer,
    utils::array_ext::{ArrayExt, OffsetsArray, SeqArrayExt},
};

use super::array_builder::ArrayBuilder;

#[derive(Debug, Clone)]
pub struct MapBuilder {
    pub name: String,
    entries_name: String,
    sorted: bool,
    pub keys: Box<ArrayBuilder>,
    pub values: Box<ArrayBuilder>,
    pub offsets: OffsetsArray<i32>,
    pub metadata: HashMap<String, String>,
}

impl MapBuilder {
    pub fn new(
        name: String,
        entries_name: String,
        sorted: bool,
        keys: ArrayBuilder,
        values: ArrayBuilder,
        is_nullable: bool,
        metadata: HashMap<String, String>,
    ) -> Result<Self> {
        Ok(Self {
            name,
            entries_name,
            sorted,
            offsets: OffsetsArray::new(is_nullable),
            keys: Box::new(keys),
            values: Box::new(values),
            metadata,
        })
    }

    pub fn take(&mut self) -> ArrayBuilder {
        ArrayBuilder::Map(Self {
            name: self.name.clone(),
            entries_name: self.entries_name.clone(),
            sorted: self.sorted,
            metadata: self.metadata.clone(),
            offsets: self.offsets.take(),
            keys: Box::new(self.keys.take()),
            values: Box::new(self.values.take()),
        })
    }

    pub fn is_nullable(&self) -> bool {
        self.offsets.validity.is_some()
    }

    pub fn into_array_and_field_meta(self) -> Result<(Array, FieldMeta)> {
        let meta = FieldMeta {
            name: self.name,
            nullable: self.offsets.is_nullable(),
            metadata: self.metadata,
        };
        let (keys, keys_meta) = (*self.keys).into_array_and_field_meta()?;
        let (values, values_meta) = (*self.values).into_array_and_field_meta()?;

        let array = Array::Map(MapArray {
            meta: MapMeta {
                entries_name: self.entries_name,
                sorted: self.sorted,
                keys: keys_meta,
                values: values_meta,
            },
            keys: Box::new(keys),
            values: Box::new(values),
            validity: self.offsets.validity,
            offsets: self.offsets.offsets,
        });
        Ok((array, meta))
    }

    pub fn reserve(&mut self, additional: usize) {
        self.offsets.reserve(additional);
    }

    pub fn serialize_default_value(&mut self) -> Result<()> {
        self.offsets.push_seq_default().ctx(self)
    }

    pub fn serialize_value<V: Serialize>(&mut self, value: V) -> Result<()> {
        value.serialize(&mut *self).ctx(self)
    }
}

impl Context for MapBuilder {
    fn annotate(&self, annotations: &mut BTreeMap<String, String>) {
        prepend(annotations, "field", &self.name);
        set_default(annotations, "data_type", "Map");
    }
}

impl<'a> Serializer for &'a mut MapBuilder {
    impl_serializer!(
        'a, MapBuilder;
        override serialize_none,
        override serialize_map,
    );

    fn serialize_none(self) -> Result<()> {
        self.offsets.push_seq_none()
    }

    fn serialize_map(self, len: Option<usize>) -> Result<Self::SerializeMap> {
        if let Some(len) = len {
            self.keys.reserve(len);
            self.values.reserve(len);
        }
        self.offsets.start_seq().ctx(self)?;
        Ok(Self::SerializeMap::Map(self))
    }
}

impl serde::ser::SerializeMap for &mut MapBuilder {
    type Ok = ();
    type Error = Error;

    fn serialize_key<T: ?Sized + Serialize>(&mut self, key: &T) -> Result<()> {
        self.offsets.push_seq_elements(1)?;
        self.keys.serialize_value(key)
    }

    fn serialize_value<T: ?Sized + Serialize>(&mut self, value: &T) -> Result<()> {
        self.values.serialize_value(value)
    }

    fn end(self) -> Result<()> {
        self.offsets.end_seq()
    }
}