safina-sync 0.2.3

Safe structs for sharing or sending data between async tasks
Documentation 
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# safina-sync

[![crates.io version](https://img.shields.io/crates/v/safina-sync.svg)](https://crates.io/crates/safina-sync)
[![license: Apache 2.0](https://gitlab.com/leonhard-llc/safina-rs/-/raw/main/license-apache-2.0.svg)](http://www.apache.org/licenses/LICENSE-2.0)
[![unsafe forbidden](https://gitlab.com/leonhard-llc/safina-rs/-/raw/main/unsafe-forbidden-success.svg)](https://github.com/rust-secure-code/safety-dance/)
[![pipeline status](https://gitlab.com/leonhard-llc/safina-rs/badges/main/pipeline.svg)](https://gitlab.com/leonhard-llc/safina-rs/-/pipelines)

Structs for sharing or sending data between async tasks.

It is part of [`safina`](https://crates.io/crates/safina), a safe async runtime.

## Features
- `Mutex` with an async lock method
- `oneshot` and `sync_channel` with async and blocking methods
- `forbid(unsafe_code)`
- Depends only on `std`
- 100% test coverage
- Works with [`safina-executor`](https://crates.io/crates/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](https://github.com/rust-lang/rust/issues/66806)
  and [const-eval#3](https://github.com/rust-lang/const-eval/issues/3).
  You can work around this with unstable
  [`core::lazy::OnceCell`](https://doc.rust-lang.org/core/lazy/struct.OnceCell.html)
  or various `unsafe` crates:
  [`lazy_static`](https://crates.io/crates/lazy_static),
  [`once_cell`](https://crates.io/crates/once_cell),
  [`lazycell`](https://crates.io/crates/lazycell), and
  [`conquer-once`](https://crates.io/crates/conquer-once).

## Documentation
<https://docs.rs/safina-sync>

## Examples
```rust
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](https://crates.io/crates/async-lock)
  - Contains a little `unsafe` code
- [futures-locks](https://crates.io/crates/futures-locks)
  - Contains a little `unsafe` code
- [futures-util](https://crates.io/crates/futures-util)
  - Very popular
  - Full of `unsafe`
- [tokio-sync](https://crates.io/crates/tokio-sync)
  - Very popular
  - Fast
  - Internally incredibly complicated
  - Full of `unsafe`

## Changelog
- v0.2.3 Fix race condition.
- v0.2.2 Fix deadlock on Linux.
- v0.2.1
  - Add `sync_channel` and `SyncSender`.
  - Add `Receiver::async_recv` to let users await without writing ugly `(&mut receiver).await`.
  - Remove `Receiver::blocking` and add `try_recv`, `recv`, etc.
- v0.2.0 - Replace `Promise` with `oneshot`, `OneSender`, and `Receiver` that supports async and blocking reads.
- v0.1.6 - Update docs.
- 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
- Add `Barrier`
- Add `RwLock`
- Add `WaitableBool`
- 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.
1. Run `./release.sh`

License: Apache-2.0