├── .gitignore ├── Cargo.toml ├── LICENSE-APACHE.txt ├── LICENSE-MIT.txt ├── README.md └── src └── lib.rs /.gitignore: -------------------------------------------------------------------------------- 1 | 2 | /target 3 | **/*.rs.bk 4 | Cargo.lock 5 | -------------------------------------------------------------------------------- /Cargo.toml: -------------------------------------------------------------------------------- 1 | [package] 2 | name = "defer" 3 | description = "Utility to defer excecution of code, inspired by go's defer statement." 4 | version = "0.2.1" 5 | documentation = "https://docs.rs/defer/" 6 | repository = "https://github.com/andrewhickman/defer/" 7 | license = "MIT/Apache-2.0" 8 | authors = ["Andrew Hickman ", "Zakarum "] 9 | edition = "2021" 10 | categories = ["memory-management", "no-std", "no-std::no-alloc", "rust-patterns"] 11 | keywords = ["defer"] 12 | 13 | [dependencies] 14 | -------------------------------------------------------------------------------- /LICENSE-APACHE.txt: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. 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IN NO EVENT SHALL THE 18 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 20 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 21 | SOFTWARE. 22 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | [![crates.io](https://img.shields.io/crates/v/defer.svg)](https://crates.io/crates/defer/) 2 | [![docs.rs](https://docs.rs/defer/badge.svg)](https://docs.rs/defer/) 3 | 4 | # defer 5 | 6 | A small crate which provides the `defer!` macro, to delay execution of an expression until the end of the scope. 7 | 8 | Consider using the [`scopeguard`](https://docs.rs/scopeguard/latest/scopeguard/) crate instead, which has many more features. 9 | 10 | ## License 11 | 12 | Licensed under either of 13 | 14 | * Apache License, Version 2.0 15 | ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0) 16 | * MIT license 17 | ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT) 18 | 19 | at your option. 20 | 21 | ## Contribution 22 | 23 | Unless you explicitly state otherwise, any contribution intentionally submitted 24 | for inclusion in the work by you, as defined in the Apache-2.0 license, shall be 25 | dual licensed as above, without any additional terms or conditions. 26 | -------------------------------------------------------------------------------- /src/lib.rs: -------------------------------------------------------------------------------- 1 | #![no_std] 2 | 3 | use core::mem::ManuallyDrop; 4 | 5 | /// Defer execution of a closure until the return value is dropped. 6 | pub fn defer(f: F) -> impl Drop 7 | where 8 | F: FnOnce(), 9 | { 10 | struct Defer(ManuallyDrop); 11 | 12 | impl Drop for Defer { 13 | fn drop(&mut self) { 14 | let f: F = unsafe { ManuallyDrop::take(&mut self.0) }; 15 | f(); 16 | } 17 | } 18 | 19 | Defer(ManuallyDrop::new(f)) 20 | } 21 | 22 | /// Defer execution of a closure until the current scope end. 23 | #[macro_export] 24 | macro_rules! defer { 25 | ($e:expr) => { 26 | let _defer = $crate::defer(|| $e); 27 | }; 28 | } 29 | 30 | #[test] 31 | fn test() { 32 | use core::cell::RefCell; 33 | 34 | let i = RefCell::new(0); 35 | 36 | { 37 | let _d = defer(|| *i.borrow_mut() += 1); 38 | assert_eq!(*i.borrow(), 0); 39 | } 40 | 41 | assert_eq!(*i.borrow(), 1); 42 | } 43 | 44 | #[test] 45 | fn test_macro() { 46 | use core::cell::RefCell; 47 | 48 | let i = RefCell::new(0); 49 | let k = RefCell::new(0); 50 | 51 | { 52 | defer!(*i.borrow_mut() += 1); 53 | defer!(*k.borrow_mut() += 1); 54 | assert_eq!(*i.borrow(), 0); 55 | assert_eq!(*k.borrow(), 0); 56 | } 57 | 58 | assert_eq!(*i.borrow(), 1); 59 | assert_eq!(*k.borrow(), 1); 60 | } 61 | --------------------------------------------------------------------------------