omango-util 0.1.6

// Copyright (c) 2024 Trung Tran <tqtrungse@gmail.com>
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

pub struct Defer<F: FnOnce()> {
    f: Option<F>,
}

impl<F: FnOnce()> Defer<F> {
    #[inline(always)]
    pub fn new(f: F) -> Defer<F> {
        Defer { f: Some(f) }
    }
}

impl<F: FnOnce()> Drop for Defer<F> {
    #[inline(always)]
    fn drop(&mut self) {
        if let Some(f) = self.f.take() {
            f();
        }
    }
}

#[cfg(test)]
mod test {
    #[test]
    fn test() {
        fn defer() {
            let a = 4u32;
            let _df = crate::defer::Defer::new(|| {
                assert_eq!(1u32, a);
            });
        }

        let result = std::panic::catch_unwind(|| {
            defer();
        });
        
        assert!(result.is_err());
    }
}