RusPiRo Singleton crate

This crate provides an easy to use singleton pattern that is safe to be used across cores.

Usage

To use this crate simply add the dependency to your Cargo.toml file:

[dependencies]
ruspiro-singleton = "0.3"

Once done on any rust file you can define a static variable as singleton of any type for safe cross core access like so:

// define the static variable
static DEMO:Singleton<Demo> = Singleton::new(Demo::new());

// define the type to be accessible as singleton
struct Demo {
    pub count: u32,
}

// implement the type that should provided as singlton
impl Demo {
    pub const fn new() -> Self {
        Demo {
            count: 0,
        }
    };
}

fn main() {
    // safely use the singleton inside the closure passed to [take_for].
    DEMO.take_for(|d| {
        d.count += 10;
    });

    // you may also return a value from the singleton to work with it after the safe singleton access
    let _current = DEMO.take_for(|d| {
        d.count
    });
}

If the singleton does only require read only access a non-blocking function could be used:

fn main() {
    DEMO.use_for(|d| {
        // d is available with immutable access only in this scenario
        println!("current count: {}", d.count);
    });
}

Limitation

The current version of the implementation does not allow lazy initialization. Only const fn functions can be used to initialize the structure instance that should be wrapped by the Singleton.

License

Licensed under Apache License, Version 2.0, (LICENSE or http://www.apache.org/licenses/LICENSE-2.0)