lifeguard issues owned values wrapped in smartpointers.
rust
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.
rust
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.
rust
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.
rust
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());
Benchmark source can be found here. Tests were run on a VirtualBox VM with 3 CPUs @ 3Ghz and 4GB of RAM.
| Test Description | Allocating Normally | Using Object Pool | Improvement
| ---------------------------------------------------------- |:-----------------------------:|:-----------------:|-----------|
| String Allocation
(String::withcapacity vs Pool::new) | 14379471 ns/iter
(+/- 939144) | 8100463 ns/iter
(+/- 208630) | ~43.67%
| String Duplication
(String::toowned vs Pool::new_from) | 22243887 ns/iter
(+/- 1251080) | 17502346 ns/iter
(+/- 1086291) | ~21.32%
| Creating a <Vec<Vec<String>>> | 1277138 ns/iter
(+/- 114681) | 727415 ns/iter
(+/- 62881) | ~43.04%
Ideas and PRs welcome!
Inspired by frankmcsherry's recycler.