protocol-droid 0.3.0

A Model Context Protocol toolkit that speaks every published spec revision, with one canonical IR behind many per-revision codecs.
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//! Keys for tests, drawn fresh for each process.
//!
//! A key written into a test as a literal is a hard-coded cryptographic value,
//! whatever it is used for, and it teaches the next reader to copy the pattern.
//! These come from the operating system's random source through the standard
//! library's hasher seed, so no test depends on a particular key.

use std::hash::{BuildHasher as _, Hasher as _, RandomState};

use super::StateKey;

/// 32 bytes no two processes share.
#[must_use]
pub fn random_bytes() -> [u8; 32] {
    let mut word = 0_u64;
    let mut left = 0_u8;
    core::array::from_fn(|_| {
        if left == 0 {
            word = RandomState::new().build_hasher().finish();
            left = 8;
        }
        let byte = u8::try_from(word & 0xff).unwrap_or_default();
        word >>= 8;
        left -= 1;
        byte
    })
}

/// A key that differs from every other call's.
#[must_use]
pub fn random_key() -> StateKey {
    StateKey::from_bytes(random_bytes())
}