strawboat 0.2.6

// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you 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::fs::File;

use arrow::array::{ListArray, MapArray, StructArray, Utf8Array};
use arrow::datatypes::DataType;
use arrow::offset::OffsetsBuffer;
use arrow::{
    array::{Array, BooleanArray, Int32Array},
    chunk::Chunk,
    datatypes::{Field, Schema},
    error::Result,
    io::parquet::write::{
        transverse, CompressionOptions, Encoding, FileWriter, RowGroupIterator, Version,
        WriteOptions,
    },
};

fn write_chunk(path: &str, schema: Schema, chunk: Chunk<Box<dyn Array>>) -> Result<()> {
    let options = WriteOptions {
        write_statistics: true,
        compression: CompressionOptions::Uncompressed,
        version: Version::V2,
        data_pagesize_limit: None,
    };

    let iter = vec![Ok(chunk)];

    let encodings = schema
        .fields
        .iter()
        .map(|f| transverse(&f.data_type, |_| Encoding::Plain))
        .collect();

    let row_groups = RowGroupIterator::try_new(iter.into_iter(), &schema, options, encodings)?;

    // Create a new empty file
    let file = File::create(path)?;

    let mut writer = FileWriter::try_new(file, schema, options)?;

    for group in row_groups {
        writer.write(group?)?;
    }
    let _size = writer.end(None)?;
    Ok(())
}

fn main() -> Result<()> {
    // mock boolean array
    let bool_array = BooleanArray::from(&[Some(true), Some(false), None]);
    let bool_field = Field::new("c0", bool_array.data_type().clone(), true);
    // mock int32 array
    let int32_array = Int32Array::from(&[Some(0), Some(1), None]);
    let int32_field = Field::new("c1", int32_array.data_type().clone(), true);

    // mock struct array
    let s1 = [Some("a"), Some("bc"), None];
    let s2 = [Some(1), Some(2), None];
    let dt = DataType::Struct(vec![
        Field::new("name", DataType::Utf8, false),
        Field::new("age", DataType::Int32, true),
    ]);
    let struct_array = StructArray::try_new(
        dt,
        vec![
            Utf8Array::<i32>::from(s1).boxed(),
            Int32Array::from(s2).boxed(),
        ],
        None,
    )?;
    let struct_field = Field::new("c2", struct_array.data_type().clone(), true);

    // mock list array
    let l1 = Int32Array::from(&[
        Some(0),
        Some(1),
        None,
        Some(2),
        Some(3),
        None,
        Some(4),
        Some(5),
        None,
    ]);
    let list_array = ListArray::try_new(
        DataType::List(Box::new(Field::new("item", l1.data_type().clone(), false))),
        OffsetsBuffer::try_from(vec![0, 3, 5, 9]).unwrap(),
        l1.boxed(),
        None,
    )?;
    let list_field = Field::new("c3", list_array.data_type().clone(), true);

    let k1 = [Some("a"), Some("b"), Some("c"), Some("d"), Some("e")];
    let v1 = [Some(1), Some(2), None, Some(3), Some(4)];
    let dt = DataType::Struct(vec![
        Field::new("key", DataType::Utf8, false),
        Field::new("value", DataType::Int32, true),
    ]);
    let inner_array = StructArray::try_new(
        dt,
        vec![
            Utf8Array::<i32>::from(k1).boxed(),
            Int32Array::from(v1).boxed(),
        ],
        None,
    )?;
    let offsets = vec![0, 1, 3, 5];
    let map_array = MapArray::new(
        DataType::Map(
            Box::new(Field::new(
                "entries",
                inner_array.data_type().clone(),
                false,
            )),
            false,
        ),
        OffsetsBuffer::try_from(offsets).unwrap(),
        inner_array.boxed(),
        None,
    );
    let map_field = Field::new("c4", map_array.data_type().clone(), true);

    let schema = Schema::from(vec![
        bool_field,
        int32_field,
        struct_field,
        list_field,
        map_field,
    ]);
    let chunk = Chunk::new(vec![
        bool_array.boxed(),
        int32_array.boxed(),
        struct_array.boxed(),
        list_array.boxed(),
        map_array.boxed(),
    ]);

    write_chunk("/tmp/input.parquet", schema, chunk)
}