lifeguard

Object Pool Manager

lifeguard issues owned values wrapped in smartpointers.

extern crate lifeguard;
use lifeguard::Pool;
//...
let pool : Pool<String> = Pool::with_size(10);
{
   let string : Recycled<String> = Pool::new_from("Hello, World!"); // Pool size is now 9
} // Values that have gone out of scope are automatically moved back into the pool.
// Pool size is 10 again

Values taken from the pool can be dereferenced to access/mutate their contents.

extern crate lifeguard;
use lifeguard::Pool;
//...
let mut pool : Pool<String> = Pool::with_size(10);
let mut string = pool.new_from("cat");
(*string).push_str("s love eating mice");
assert_eq!("cats love eating mice", *string);

Values can be unwrapped, detaching them from the pool.

let mut pool : Pool<String> = Pool::with_size(10);
{
  let string : String = pool.new().detach();
} // The String goes out of scope and is dropped; it is not returned to the pool
assert_eq!(9, pool.size());

Values can be manually entered into / returned to the pool.

let mut pool : Pool<String> = Pool::with_size(10);
{
  let string : String = pool.detached(); // An unwrapped String, detached from the Pool
  assert_eq!(9, pool.size());
  let rstring : Recycled<String> = pool.attach(string); // The String is attached to the pool again
  assert_eq!(9, pool.size());
} // rstring goes out of scope and is added back to the pool
assert_eq!(10, pool.size());

Highly Unscientific Benchmarks

Benchmark source can be found here. Tests were run on a VirtualBox VM with 3 CPUs @ 3Ghz and 4GB of RAM.

Ideas and PRs welcome!

Inspired by frankmcsherry's recycler.