Snapshot Lock | snaplock

crates.io

MVCC without transactions or something

[!WARNING] This library is not production ready

ReadWrite lock for Rust leveraging data versioning.

Features:

• async : Adds new_async constructor. .write() method becomes async

Example:

use snaplock::SnapshotLock;

fn main() {
    let lock = SnapshotLock::new(String::from("Hello"));
    
    // Multiple readers can access the data concurrently
    let reader1 = lock.read();
    let reader2 = lock.read();
    assert_eq!(*reader1, "Hello");
    assert_eq!(*reader2, "Hello");
    
    // Writers have exclusive access
    {
        let mut writer = lock.write();
        writer.push_str(", World!");
        
        // During write readers see old values
        let reader = lock.read();
        assert_eq!(*reader, "Hello");
    }
    
    // When write is finished, new readers see the updated value
    let reader3 = lock.read();
    assert_eq!(*reader3, "Hello, World!");
    
    // Old readers still see their old value
    assert_eq!(*reader1, "Hello");
    assert_eq!(*reader2, "Hello");
}

MSRV Policy:

There is none. Current Minimum Supported Rust Version is 1.85.0

Alternatives:

• crossbeam::sync::SharedLock - A sharded reader-writer lock.
• vlock - A fast and scalable multi-version shared state lock with wait-free read access.
• parking_lot - More compact and efficient implementations of the standard synchronization primitives.