tendermint 0.6.0

Tendermint is a high-performance blockchain consensus engine that powers Byzantine fault tolerant applications written in any programming language. This crate provides types for representing information about Tendermint blockchain networks, including chain IDs, block IDs, and block heights.
Documentation 
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//! Nodes in Tendermint blockchain networks

use crate::error::Error;
#[cfg(feature = "serde")]
use serde::{de, Deserialize, Deserializer, Serialize, Serializer};
use sha2::{Digest, Sha256};
use signatory::ed25519;
use std::{
    fmt::{self, Display},
    str::FromStr,
};
use subtle::{self, ConstantTimeEq};
use subtle_encoding::hex;

/// Size of a Node ID in bytes
pub const ID_LENGTH: usize = 20;

/// Node IDs
#[derive(Copy, Clone, Debug, Hash)]
pub struct Id([u8; ID_LENGTH]);

impl Id {
    /// Create a new Node ID from raw bytes
    pub fn new(bytes: [u8; ID_LENGTH]) -> Id {
        Id(bytes)
    }

    /// Borrow the node ID as a byte slice
    pub fn as_bytes(&self) -> &[u8] {
        &self.0[..]
    }
}

impl AsRef<[u8]> for Id {
    fn as_ref(&self) -> &[u8] {
        self.as_bytes()
    }
}

impl ConstantTimeEq for Id {
    #[inline]
    fn ct_eq(&self, other: &Id) -> subtle::Choice {
        self.as_bytes().ct_eq(other.as_bytes())
    }
}

impl Display for Id {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        for byte in &self.0 {
            write!(f, "{:02X}", byte)?;
        }
        Ok(())
    }
}

impl From<ed25519::PublicKey> for Id {
    fn from(pk: ed25519::PublicKey) -> Id {
        let digest = Sha256::digest(pk.as_bytes());
        let mut bytes = [0u8; ID_LENGTH];
        bytes.copy_from_slice(&digest[..ID_LENGTH]);
        Id(bytes)
    }
}

/// Decode Node ID from hex
impl FromStr for Id {
    type Err = Error;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        // Accept either upper or lower case hex
        let bytes = hex::decode_upper(s)
            .or_else(|_| hex::decode(s))
            .map_err(|_| Error::Parse)?;

        if bytes.len() != ID_LENGTH {
            return Err(Error::Parse);
        }

        let mut result_bytes = [0u8; ID_LENGTH];
        result_bytes.copy_from_slice(&bytes);
        Ok(Id(result_bytes))
    }
}

#[cfg(feature = "serde")]
impl<'de> Deserialize<'de> for Id {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        let s = String::deserialize(deserializer)?;
        Self::from_str(&s).map_err(|_| {
            de::Error::custom(format!(
                "expected {}-character hex string, got {:?}",
                ID_LENGTH * 2,
                s
            ))
        })
    }
}

#[cfg(feature = "serde")]
impl Serialize for Id {
    fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
        self.to_string().serialize(serializer)
    }
}