Crate safe_lock

ARCHIVED ARCHIVED ARCHIVED

This crate is archived and will not be updated.

std::sync::Mutex got a const constructor, making this crate unnecessary. See rustlang/rust#66806. Don’t use this crate. Just use std::sync::Mutex.

For folks who continue using this crate, SafeLock is now a simple wrapper around std::sync::Mutex, so their tests will run a bit faster.

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safe-lock

A simple SafeLock struct.

Use Cases

• Run tests sequentially
• Prevent concurrent operations on atomic values
• Prevent concurrent operations on data and systems outside the Rust runtime

Features

• Const constructor
• Depends only on std
• forbid(unsafe_code)
• 100% test coverage

Limitations

• Not a Mutex<T>. Does not contain a value.
• Unoptimized. Uses AtomicBool in a spinlock, not fast OS locks.
• Not a fair lock. If multiple threads acquire the lock in loops, some may never acquire it.

Alternatives

• rusty-fork
  • Run tests in separate processes
• std::sync::Mutex
  • Part of the Rust standard library: well reviewed, well tested, and well maintained.
  • Uses fast OS locks
  • Has no const constructor. See rust#66806 and const-eval#3. You can work around this with unstable core::lazy::OnceCell or various unsafe crates: lazy_static, once_cell, lazycell, and conquer-once.
• parking_lot
  • Well written code. Many hope that it will end up in the Rust standard library someday.
  • Contains plenty of unsafe
• try-lock
  • Popular
  • No dependencies, no_std
  • Uses unsafe
• ruspiro-lock
  • Sync and async locks
  • No dependencies, no_std
  • Uses unsafe
• flexible-locks
  • Lots of unsafe
  • Uses fast OS locks
  • Unmaintained

Related Crates

• safina-sync provides a safe async Mutex

Example

Make some tests run sequentially so they don’t interfere with each other:

use safe_lock::SafeLock;
static LOCK: SafeLock = SafeLock::new();

[#test]
fn test1() {
    let _guard = LOCK.lock();
    // ...
}

[#test]
fn test2() {
    let _guard = LOCK.lock();
    // ...
}

Cargo Geiger Safety Report

Changelog

• v0.1.4
  • Make SafeLock a wrapper around std::sync::Mutex since it got a const constructor.
  • Add archival notice.
• v0.1.3 - Increase test coverage
• v0.1.2 - Use Acquire and Release ordering
• v0.1.1 - Update docs
• v0.1.0 - Initial version

Structs

• SafeLock
  A lock.
• SafeLockGuard
  A handle to the acquired lock. Drop this to release the lock.