prost-arrow 0.0.3

Derives apache arrow array builders for protobuf messages generated by prost.
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

use std::any::Any;
use std::sync::Arc;

use arrow_array::builder::{ArrayBuilder, BinaryBuilder, StringBuilder};
use arrow_array::ArrayRef;
use arrow_schema::DataType;
use prost::alloc::string::String;

use crate::traits::{ArrowBuilder, ToArrow};

impl ToArrow for String {
    type Item = String;
    type Builder = ArrowStringBuilder;

    fn to_datatype() -> DataType {
        DataType::Utf8
    }
}

impl ToArrow for Vec<u8> {
    type Item = Vec<u8>;
    type Builder = ArrowBinaryBuilder;

    fn to_datatype() -> DataType {
        DataType::Binary
    }
}

pub struct ArrowStringBuilder {
    builder: StringBuilder,
}

impl ArrowBuilder<String> for ArrowStringBuilder {
    fn new_with_capacity(capacity: usize) -> Self {
        Self {
            builder: StringBuilder::with_capacity(capacity, capacity * 1024),
        }
    }

    fn append_value(&mut self, value: String) {
        self.builder.append_value(value)
    }

    fn append_option(&mut self, value: Option<String>) {
        self.builder.append_option(value)
    }
}

impl ArrayBuilder for ArrowStringBuilder {
    fn len(&self) -> usize {
        self.builder.len()
    }

    fn finish(&mut self) -> ArrayRef {
        Arc::new(self.builder.finish())
    }

    fn finish_cloned(&self) -> ArrayRef {
        Arc::new(self.builder.finish_cloned())
    }

    fn as_any(&self) -> &dyn Any {
        self
    }

    fn as_any_mut(&mut self) -> &mut dyn Any {
        self
    }

    fn into_box_any(self: Box<Self>) -> Box<dyn Any> {
        self
    }
}

pub struct ArrowBinaryBuilder {
    builder: BinaryBuilder,
}

impl ArrowBuilder<Vec<u8>> for ArrowBinaryBuilder {
    fn new_with_capacity(capacity: usize) -> Self {
        Self {
            builder: BinaryBuilder::with_capacity(capacity, capacity * 1024),
        }
    }

    fn append_value(&mut self, value: Vec<u8>) {
        self.builder.append_value(value)
    }

    fn append_option(&mut self, value: Option<Vec<u8>>) {
        self.builder.append_option(value)
    }
}

impl ArrayBuilder for ArrowBinaryBuilder {
    fn len(&self) -> usize {
        self.builder.len()
    }

    fn finish(&mut self) -> ArrayRef {
        Arc::new(self.builder.finish())
    }

    fn finish_cloned(&self) -> ArrayRef {
        Arc::new(self.builder.finish_cloned())
    }

    fn as_any(&self) -> &dyn Any {
        self
    }

    fn as_any_mut(&mut self) -> &mut dyn Any {
        self
    }

    fn into_box_any(self: Box<Self>) -> Box<dyn Any> {
        self
    }
}