Crate cross_locks

cross‑locks

A single‑source, zero‑dependency¹ implementation of Supabase/GoTrue‑style global exclusive locks that work identically across every runtime.

target / runtime	compile‑time feature	backend used by DefaultLock
Native (Tokio, multi‑thread)	native	fair FIFO queue (Notify)
Browser WASM (2022 + navigator.locks)	browser	Navigator.locks.request
Head‑less WASM (Node / WASI / tests)	wasm	no‑op passthrough

* Safari shipped the LockManager API in 16.4 (2023‑03).

Guarantees

• FIFO fairness for every waiter requesting the same lock name on native.
• Zero‑timeout try‑lock (Duration::ZERO) mirrors the semantics of the JS SDK.
• Task‑local re‑entrancy helper demonstrated in the test‑suite.
• Arc<T> automatically implements GlobalLock, ideal for storing in an Axum State, OnceCell, etc.

---

¹ Outside the optional features listed below (async‑trait, thiserror, Tokio / wasm‑bindgen).

# Cargo.toml – choose exactly ONE backend
[dependencies]
cross-locks = { version = "*", default-features = false, features = ["native"] }
# or  "browser"  |  "wasm"

# run the exhaustive native test‑suite
cargo test --features native

# browser smoke‑test (headless Firefox)
wasm-pack test --firefox --headless --features browser

Macros

async_test

Expands to tokio::test on native targets and to a wasm_bindgen_test module on wasm32 (so the name doesn’t clash with the outer function space).

dual_test

Shorthand when you don’t need a dedicated module on wasm (i.e. the test name is unique anyway). Generates either a tokio::test or a wasm_bindgen_test for the same async function.

Structs

NoopLock

Passthrough implementation – used by the wasm (Node/WASI) feature and in single‑thread CLI tests.

Enums

LockError

Errors returned by GlobalLock::with_lock.

Traits

GlobalLock

Back‑end agnostic trait. On wasm32 the Send bounds are automatically relaxed (?Send).