gotatun 0.5.0

// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at https://mozilla.org/MPL/2.0/.
//
// This file incorporates work covered by the following copyright and
// permission notice:
//
//   Copyright (c) Mullvad VPN AB. All rights reserved.
//   Copyright (c) 2019 Cloudflare, Inc. All rights reserved.
//
// SPDX-License-Identifier: MPL-2.0

use base64::{Engine as _, prelude::BASE64_STANDARD};

pub struct KeyBytes(pub [u8; 32]);

impl std::str::FromStr for KeyBytes {
    type Err = &'static str;

    /// Can parse a secret key from a hex or base64 encoded string.
    fn from_str(s: &str) -> Result<Self, Self::Err> {
        let mut internal = [0u8; 32];

        match s.len() {
            64 => {
                // Try to parse as hex
                for i in 0..32 {
                    internal[i] = u8::from_str_radix(&s[i * 2..=i * 2 + 1], 16)
                        .map_err(|_| "Illegal character in key")?;
                }
            }
            43 | 44 => {
                // Try to parse as base64
                if let Ok(decoded_key) = BASE64_STANDARD.decode(s) {
                    if decoded_key.len() == internal.len() {
                        internal[..].copy_from_slice(&decoded_key);
                    } else {
                        return Err("Illegal character in key");
                    }
                }
            }
            _ => return Err("Illegal key size"),
        }

        Ok(KeyBytes(internal))
    }
}

impl std::fmt::Debug for KeyBytes {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.debug_tuple("KeyBytes").field(&..).finish()
    }
}

impl From<[u8; 32]> for KeyBytes {
    fn from(bytes: [u8; 32]) -> Self {
        KeyBytes(bytes)
    }
}