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

// Copyright 2023 WHERE TRUE Technologies.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use std::sync::Arc;

use arrow::datatypes::{Field, Schema, SchemaRef};
use exon_common::DEFAULT_BATCH_SIZE;
use object_store::ObjectStore;

/// Configuration for a FCS datasource.
pub struct FCSConfig {
    /// The number of records to read at a time.
    pub batch_size: usize,
    /// The object store to use.
    pub object_store: Arc<dyn ObjectStore>,
    /// The file schema to use.
    pub file_schema: Arc<arrow::datatypes::Schema>,
    /// Any projections to apply to the resulting batches.
    pub projection: Option<Vec<usize>>,
}

impl FCSConfig {
    /// Create a new FCS configuration.
    pub fn new(object_store: Arc<dyn ObjectStore>, file_schema: SchemaRef) -> Self {
        Self {
            batch_size: DEFAULT_BATCH_SIZE,
            object_store,
            file_schema,
            projection: None,
        }
    }

    /// Set the batch size.
    pub fn with_batch_size(mut self, batch_size: usize) -> Self {
        self.batch_size = batch_size;
        self
    }

    /// Set the projection.
    pub fn with_projection(mut self, projection: Vec<usize>) -> Self {
        self.projection = Some(projection);
        self
    }
}

#[derive(Debug, Default)]
pub struct FCSSchemaBuilder {
    file_fields: Vec<Field>,
    partition_fields: Vec<Field>,
}

impl FCSSchemaBuilder {
    pub fn new() -> Self {
        Self {
            file_fields: vec![],
            partition_fields: vec![],
        }
    }

    pub fn add_file_fields(&mut self, fields: Vec<Field>) {
        self.file_fields.extend(fields)
    }

    /// Add fields to the schema builder.
    pub fn add_partition_fields(&mut self, fields: Vec<Field>) {
        self.partition_fields.extend(fields)
    }

    /// Add build the schema and projection.
    pub fn build(self) -> (Schema, Vec<usize>) {
        let mut fields = self.file_fields.clone();
        fields.extend(self.partition_fields);

        let schema = Schema::new(fields);

        let projection = (0..self.file_fields.len()).collect();

        (schema, projection)
    }
}