/Users/andrewlamb/Software/datafusion/datafusion/common/src/alias.rs
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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 | | |
18 | | use std::sync::atomic::{AtomicUsize, Ordering}; |
19 | | |
20 | | /// A utility struct that can be used to generate unique aliases when optimizing queries |
21 | | #[derive(Debug)] |
22 | | pub struct AliasGenerator { |
23 | | next_id: AtomicUsize, |
24 | | } |
25 | | |
26 | | impl Default for AliasGenerator { |
27 | 0 | fn default() -> Self { |
28 | 0 | Self { |
29 | 0 | next_id: AtomicUsize::new(1), |
30 | 0 | } |
31 | 0 | } |
32 | | } |
33 | | |
34 | | impl AliasGenerator { |
35 | | /// Create a new [`AliasGenerator`] |
36 | 0 | pub fn new() -> Self { |
37 | 0 | Self::default() |
38 | 0 | } |
39 | | |
40 | | /// Return a unique alias with the provided prefix |
41 | 0 | pub fn next(&self, prefix: &str) -> String { |
42 | 0 | let id = self.next_id.fetch_add(1, Ordering::Relaxed); |
43 | 0 | format!("{prefix}_{id}") |
44 | 0 | } |
45 | | } |