commit	8753cbdcb9ef4925b10dc14060254076559b2d07	[log] [tgz]
author	James Farrell <jamesfarrell@google.com>	Wed May 22 23:45:12 2024 +0000
committer	Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>	Wed May 22 23:45:12 2024 +0000
tree	859a8f02a99fc312bce0a77351181d48413be715
parent	4ab9e3575f0eeabf632d167e9385852d171dff2a [diff]
parent	a9366dc763025fae57485e38367258711f12258d [diff]

tree: 859a8f02a99fc312bce0a77351181d48413be715

README.md

scopeguard

Rust crate for a convenient RAII scope guard that will run a given closure when it goes out of scope, even if the code between panics (assuming unwinding panic).

The defer! macro and guard are no_std compatible (require only core), but the on unwinding / not on unwinding strategies require linking to std. By default, the use_std crate feature is enabled. Disable the default features for no_std support.

Please read the API documentation here.

Minimum supported Rust version: 1.20

How to use

#[macro_use(defer)]
extern crate scopeguard;

use scopeguard::guard;

fn f() {
    defer! {
        println!("Called at return or panic");
    }
    panic!();
}

use std::fs::File;
use std::io::Write;

fn g() {
    let f = File::create("newfile.txt").unwrap();
    let mut file = guard(f, |f| {
        // write file at return or panic
        let _ = f.sync_all();
    });
    // access the file through the scope guard itself
    file.write_all(b"test me\n").unwrap();
}

Recent Changes

1.2.0
- Use ManuallyDrop instead of mem::forget in into_inner. (by @willtunnels)
- Warn if the guard is not assigned to a variable and is dropped immediately instead of at the scope's end. (by @sergey-v-galtsev)
1.1.0
- Change macros (defer!, defer_on_success! and defer_on_unwind!) to accept statements. (by @konsumlamm)
1.0.0
- Change the closure type from FnMut(&mut T) to FnOnce(T): Passing the inner value by value instead of a mutable reference is a breaking change, but allows the guard closure to consume it. (by @tormol)
- Add defer_on_success!, guard_on_success() and OnSuccess strategy, which triggers when scope is exited without panic. It's the opposite to defer_on_unwind! / guard_on_unwind() / OnUnwind.
- Add ScopeGuard::into_inner(), which “defuses” the guard and returns the guarded value. (by @tormol)
- Implement Sync for guards with non-Sync closures.
- Require Rust 1.20
0.3.3
- Use #[inline] on a few more functions by @stjepang (#14)
- Add examples to crate documentation
0.3.2
- Add crate categories
0.3.1
- Add defer_on_unwind!, Strategy trait
- Rename Guard → ScopeGuard
- Add ScopeGuard::with_strategy.
- ScopeGuard now implements Debug.
- Require Rust 1.11
0.2.0
- Require Rust 1.6
- Use no_std unconditionally
- No other changes
0.1.2
- Add macro defer!