FakeOwned

Have you ever wanted to store (String, String) as a key-pair in standard Hashmap/Btreemap, but suddenly realised that all lookups will require string allocations because of bad hashmap API?

Or may be you found a great library which solves all your problems but some misguided fool used &String instead of &str in their public API and now you have to allocate strings?

This crate provides A SOLUTION

BEHOLD! [FakeOwned] !

Now you can safely go

&str -> &String

&[T] -> &Vec<T>

(&str, &str) -> &(String, String)

[&str; N] -> &[String; N]

and any other combinations.

Without copies and nasty allocations.

But beware! DON'T USE IT UNLESS YOU ARE DESPERATE ENOUGH

use std::{collections::HashMap, ops::Deref};
use fakeowned::FakeOwned;
let map = HashMap::<(String, String), u32>::from_iter(
       [(("key1".to_string(), "key2".to_string()), 42)]
);
// This doesn't work: expected &(String, String)
// map.get(("key1", "key2"));
// You have to allocate strings. That's sad
let x = map.get(&("key1".to_string(), "key2".to_string()));
assert_eq!(x, Some(&42));
// This works without string allocations
let x = map.get(&("key1", "key2").fake_owned());
assert_eq!(x, Some(&42));

This crate highly relies on the fact that unsafe functions:

• Vec::from_raw_parts
• String::from_raw_parts Don't cause any nonsence, if the returned value immediatelly wrapped into [std::mem::ManuallyDrop]