cedar_policy_core/parser/
util.rs

1/*
2 * Copyright Cedar Contributors
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      https://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17//! Utility functions used by multiple parts of the parser.
18
19use super::err::ParseErrors;
20
21type Result<T> = std::result::Result<T, ParseErrors>;
22
23/// Combine two `Result`s into a single `Result`
24#[inline]
25pub fn flatten_tuple_2<T1, T2>(res1: Result<T1>, res2: Result<T2>) -> Result<(T1, T2)> {
26    // WARNING: Do not refactor without considering performance. See
27    // https://github.com/cedar-policy/cedar/pull/1649 for more details.
28    match res1 {
29        Ok(v1) => match res2 {
30            Ok(v2) => Ok((v1, v2)),
31            Err(errs2) => Err(errs2),
32        },
33        Err(mut errs1) => match res2 {
34            Ok(_) => Err(errs1),
35            Err(errs2) => {
36                errs1.extend(errs2);
37                Err(errs1)
38            }
39        },
40    }
41}
42
43/// Combine three `Result`s into a single `Result`
44pub fn flatten_tuple_3<T1, T2, T3>(
45    res1: Result<T1>,
46    res2: Result<T2>,
47    res3: Result<T3>,
48) -> Result<(T1, T2, T3)> {
49    let ((v1, v2), v3) = flatten_tuple_2(flatten_tuple_2(res1, res2), res3)?;
50    Ok((v1, v2, v3))
51}
52
53/// Combine four `Result`s into a single `Result`
54pub fn flatten_tuple_4<T1, T2, T3, T4>(
55    res1: Result<T1>,
56    res2: Result<T2>,
57    res3: Result<T3>,
58    res4: Result<T4>,
59) -> Result<(T1, T2, T3, T4)> {
60    let (((v1, v2), v3), v4) =
61        flatten_tuple_2(flatten_tuple_2(flatten_tuple_2(res1, res2), res3), res4)?;
62    Ok((v1, v2, v3, v4))
63}
cedar_policy_core/parser/util.rs

cedar_policy_core/parser/
util.rs
