use crate::{borrowed, SHA1_SIZE};use bstr::ByteSlice;use std::{fmt, io, ops::Deref}; /// An owned SHA1 identifying objects#[derive(PartialEq, Eq, Debug, Hash, Ord, PartialOrd, Clone, Copy)]#[cfg_attr(feature = "serde1", derive(serde::Serialize, serde::Deserialize))]pub struct Id([u8; SHA1_SIZE]); impl Id {    pub fn new_sha1(id: [u8; SHA1_SIZE]) -> Self {        Id(id)    }    pub fn from_20_bytes(b: &[u8]) -> Id {        let mut id = [0; SHA1_SIZE];        id.copy_from_slice(b);        Id(id)    }    pub fn from_borrowed_sha1(b: &[u8; SHA1_SIZE]) -> Id {        let mut id = [0; SHA1_SIZE];        id.copy_from_slice(&b[..]);        Id(id)    }    pub fn null_sha1() -> Id {        Id([0u8; 20])    }     pub fn from_40_bytes_in_hex(buf: &[u8]) -> Result<Id, hex::FromHexError> {        use hex::FromHex;        Ok(Id(<[u8; 20]>::from_hex(buf)?))    }     pub fn to_borrowed(&self) -> borrowed::Id {        borrowed::Id::from(&self.0)    }    pub fn sha1(&self) -> &[u8; SHA1_SIZE] {        &self.0    }    pub fn to_hex(&self) -> [u8; SHA1_SIZE * 2] {        let mut hex_buf = [0u8; 40];        hex::encode_to_slice(self.0, &mut hex_buf).expect("we can count");        hex_buf    }    pub fn as_slice(&self) -> &[u8] {        self.0.as_ref()    }    pub fn write_to(&self, mut out: impl io::Write) -> io::Result<()> {        out.write_all(&self.to_hex())    }} impl Deref for Id {    type Target = [u8; SHA1_SIZE];     fn deref(&self) -> &Self::Target {        &self.0    }} impl fmt::Display for Id {    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {        write!(f, "{}", &self.to_hex().as_bstr())    }}