arrow_select/coalesce/
generic.rs

1// Licensed to the Apache Software Foundation (ASF) under one
2// or more contributor license agreements.  See the NOTICE file
3// distributed with this work for additional information
4// regarding copyright ownership.  The ASF licenses this file
5// to you under the Apache License, Version 2.0 (the
6// "License"); you may not use this file except in compliance
7// with the License.  You may obtain a copy of the License at
8//
9//   http://www.apache.org/licenses/LICENSE-2.0
10//
11// Unless required by applicable law or agreed to in writing,
12// software distributed under the License is distributed on an
13// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
14// KIND, either express or implied.  See the License for the
15// specific language governing permissions and limitations
16// under the License.
17
18use super::InProgressArray;
19use crate::concat::concat;
20use arrow_array::ArrayRef;
21use arrow_schema::ArrowError;
22
23/// Generic implementation for [`InProgressArray`] that works with any type of
24/// array.
25///
26/// Internally, this buffers arrays and then calls other kernels such as
27/// [`concat`] to produce the final array.
28///
29/// [`concat`]: crate::concat::concat
30#[derive(Debug)]
31pub(crate) struct GenericInProgressArray {
32    /// The current source
33    source: Option<ArrayRef>,
34    /// The buffered array slices
35    buffered_arrays: Vec<ArrayRef>,
36}
37
38impl GenericInProgressArray {
39    /// Create a new `GenericInProgressArray`
40    pub(crate) fn new() -> Self {
41        Self {
42            source: None,
43            buffered_arrays: vec![],
44        }
45    }
46}
47impl InProgressArray for GenericInProgressArray {
48    fn set_source(&mut self, source: Option<ArrayRef>) {
49        self.source = source
50    }
51
52    fn copy_rows(&mut self, offset: usize, len: usize) -> Result<(), ArrowError> {
53        let source = self.source.as_ref().ok_or_else(|| {
54            ArrowError::InvalidArgumentError(
55                "Internal Error: GenericInProgressArray: source not set".to_string(),
56            )
57        })?;
58        let array = source.slice(offset, len);
59        self.buffered_arrays.push(array);
60        Ok(())
61    }
62
63    fn finish(&mut self) -> Result<ArrayRef, ArrowError> {
64        // Concatenate all buffered arrays into a single array, which uses 2x
65        // peak memory
66        let array = concat(
67            &self
68                .buffered_arrays
69                .iter()
70                .map(|array| array.as_ref())
71                .collect::<Vec<_>>(),
72        )?;
73        self.buffered_arrays.clear();
74        Ok(array)
75    }
76}
arrow_select/coalesce/generic.rs

arrow_select/coalesce/
generic.rs
