Crate safina_sync

Structs for sharing or sending data between async tasks.

It is part of safina, a safe async runtime.

Features

• safina_sync::Mutex has an async lock method
• safina_sync::Promise is a one-shot channel which you can await
• forbid(unsafe_code)
• Depends only on std
• 100% test coverage
• Works with safina-executor or any async executor

Limitations

• Allocates
• No const constructor. Uses std::sync::Mutex internally, which does not have a 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.

Documentation

https://docs.rs/safina-sync

Examples

use std::sync::Arc;
use safina_async_test::async_test;
use safina_sync::Mutex;
let shared_counter: Arc<Mutex<u32>> = get_shared_data();
{
    let mut counter_guard = shared_counter.lock().await;
    *counter_guard += 1;
    // some_async_fn().await; // Cannot await while holding a MutexGuard.
}
some_async_fn().await; // Await is ok after releasing MutexGuard.

Alternatives

• async-lock
  • Contains a little unsafe code
• futures-locks
  • Contains a little unsafe code
• futures-util
  • Very popular
  • Full of unsafe
• tokio-sync
  • Very popular
  • Fast
  • Internally incredibly complicated
  • Full of unsafe

Changelog

• v0.1.5 - Update docs
• v0.1.4 - Update docs, make MutexGuard::new non-public
• v0.1.3 - Fix Promise type parameter
• v0.1.2 - Add Promise
• v0.1.1 - Improve Mutex performance when there are many waiters
• v0.1.0 - First published version

TO DO

• DONE - Implement Mutex with tests & docs
• DONE - Publish on crates.io
• DONE - Add Promise
• Add Barrier
• Add RwLock
• Add WaitableBool
• Add Channel (single receiver)
• Add UnboundedChannel
• Add WaitableQueue (multiple receivers)
• Add UnboundedWaitableQueue
• Add Topic (copies message to every receiver)

Release Process

1. Edit Cargo.toml and bump version number.
2. Run ./release.sh

Structs

Mutex	A wrapper around std::sync::Mutex with an async lock method.
MutexGuard	An RAII scoped lock of a Mutex. It automatically unlocks the mutex when dropped (falls out of scope).
Promise	A Future that resolves when you call set on its clone.