serde-cow

See the documentation on docs.rs or build locally with cargo doc --no-deps --open.

lib.rs:

A small library with a [Cow] wrappers that implements serde::Deserialize in the ways that should be expected.

By default, [Cow] is always deserialized to the Cow::Owned variant due to a lack of specialisation, but this library provides CowStr and CowBytes which deserialize to Cow::Borrowed if possible, borrowing from the original data.

Example

use std::borrow::Cow;

use serde_cow::CowStr;

let source = r#""Hello World""#;

let normal: Cow<str> = serde_json::from_str(source).unwrap();
assert!(matches!(normal, Cow::Owned(_))); // Wasteful!

let efficent: CowStr = serde_json::from_str(source).unwrap();
assert!(matches!(efficent.0, Cow::Borrowed(_))); // Zero copy!