Borrowed Strings: API Designs That Cut 94% of Allocations

The provided Rust code demonstrates several techniques for optimizing string handling in a high-performance application. Here's a breakdown of each pattern and its real-world implications:

Pattern 1: String Interning for Repeated Values

Code Example:

rust
 
1use std::collections::HashSet;
2use once_cell::sync::Lazy;
3use std::sync::Mutex;
4
5static STRING_POOL: Lazy<Mutex<HashSet<&'static str>>> = Lazy::new(|| Mutex::new(HashSet::new()));
6
7/// Interns a string, returning the same `&'static str` if it has been seen before.
8pub fn intern(s: &str) -> &'static str {
9    let mut pool = STRING_POOL.lock().unwrap();
10    if let Some(&interned) = pool.get(s) {
11        return interned;
12    }
13    let leaked: &'static str = Box::leak(s.to_string().into_boxed_str());
14    pool.insert(leaked);
15    leaked
16}

Real-World Application: In a system where certain strings are repeatedly used, such as user statuses or common HTTP methods and status codes, interned strings can significantly reduce memory usage. For example:

• User Statuses: Instead of storing

Read the full article at DEV Community

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