shred 0.2.0

Dispatches systems in parallel which need read access to some resources, and write access to others.

shred - Shared resource dispatcher

Build Status MIT/Apache

This library allows to dispatch systems, which can have interdependencies, shared and exclusive resource access, in parallel.


extern crate shred;

use shred::{DispatcherBuilder, Fetch, FetchMut, Resource, Resources, System};

struct ResA;

impl Resource for ResA {}

struct ResB;

impl Resource for ResB {}

struct PrintSystem;

// Systems should be generic over the
// context if possible, so it's easy
// to introduce one.
impl<'a, C> System<'a, C> for PrintSystem {
    type SystemData = (Fetch<'a, ResA>, FetchMut<'a, ResB>);

    fn work(&mut self, data: Self::SystemData, _: C) {
        let (a, mut b) = data;

        println!("{:?}", &*a);
        println!("{:?}", &*b);

        *b = ResB; // We can mutate ResB here
        // because it's `FetchMut`.

fn main() {
    let mut resources = Resources::new();
    let mut dispatcher = DispatcherBuilder::new()
        .add(PrintSystem, "print", &[]) // Adds a system "print" without dependencies
    resources.add(ResA, ());
    resources.add(ResB, ());

    // We can even pass a context,
    // but we don't need one here
    // so we pass `()`.
    dispatcher.dispatch(&mut resources, ());

Please see the benchmark for a bigger (and useful) example.

Required Rust version

1.17 stable


  • lock-free
  • no channels or similar functionality used (-> less overhead)
  • allows lifetimes (opposed to 'static only)


Contribution is highly welcome! If you'd like another feature, just create an issue. You can also help out if you want to; just pick a "help wanted" issue. If you need any help, feel free to ask!

All contributions are assumed to be dual-licensed under MIT/Apache-2.


shred is distributed under the terms of both the MIT license and the Apache License (Version 2.0).