50 lines
1.7 KiB
Rust
50 lines
1.7 KiB
Rust
// Copyright (C) 2025 The Kashin Vladislav (Rust adaptation author)
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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use std::borrow::Cow;
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/// Strips prefix of given string Cow. Returns option with `Some` if
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/// prefix found and stripped.
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///
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/// Calls `drain` if string is owned and returns slice if string is borrowed
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pub fn strip_cow_prefix<'a>(cow: Cow<'a, str>, prefix: &str) -> Option<Cow<'a, str>> {
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match cow {
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Cow::Borrowed(s) => s.strip_prefix(prefix).map(| s | Cow::Borrowed(s)),
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Cow::Owned(mut s) => {
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if s.starts_with(prefix) {
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s.drain(0..prefix.len());
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return Some(Cow::Owned(s));
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}
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None
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}
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}
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}
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#[cfg(test)]
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mod tests {
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use std::borrow::Cow;
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use crate::string_util::strip_cow_prefix;
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#[test]
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fn test_usage() {
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let str_to_strip = Cow::Owned("test0:test".to_owned());
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let stripped = strip_cow_prefix(str_to_strip, "test0");
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assert_eq!(stripped, Some(Cow::Owned(":test".to_owned())));
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let str_to_strip = Cow::Owned("test:test0".to_owned());
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let stripped = strip_cow_prefix(str_to_strip, "test0");
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assert_eq!(stripped, None)
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}
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} |