generational-indextree

Arena based tree structure with support for removing nodes

This arena tree structure is using just a single GenerationalArena and indices instead of reference counted pointers. This means there is no RefCell and mutability is handled in a way much more idiomatic to Rust through unique (&mut) access to the arena. The tree can be sent or shared across threads like a Vec. This enables general multiprocessing support like parallel tree traversals.

Credits

This crate is a fork of the indextree crate, but with a generational arena to store the nodes instead of a Vec. This enables us to remove nodes and use the vacant spots to insert new nodes, without suffering from the ABA problem, as explained in the generational-arena crate.

We do sacrifice the rayon support in indextree in favor of the improved remove node api.

This package was forked from the excelent https://github.com/saschagrunert/indextree crate. The backing store was replaced by https://github.com/fitzgen/generational-arena, to improve support for removing nodes and reusing the space.

Example usage

use generational_indextree::Arena;

// Create a new arena
let arena = &mut Arena::new();

// Add some new nodes to the arena
let a = arena.new_node(1);
let b = arena.new_node(2);

// Append a to b
assert!(a.append(b, arena).is_ok());
assert_eq!(b.ancestors(arena).into_iter().count(), 2);