use crate::{    extension::{Link, Signature},    util::split_at_pos,}; pub const SIGNATURE: Signature = *b"link"; pub struct Bitmaps {    pub delete: git_bitmap::ewah::Vec,    pub replace: git_bitmap::ewah::Vec,} pub mod decode {    use quick_error::quick_error;     quick_error! {        #[derive(Debug)]        pub enum Error {            Corrupt(message: &'static str) {                display("{}", message)            }            BitmapDecode{err: git_bitmap::ewah::decode::Error, kind: &'static str} {                display("{} bitmap corrupt", kind)                source(err)            }        }    }} pub(crate) fn decode(data: &[u8], object_hash: git_hash::Kind) -> Result<Link, decode::Error> {    let (id, data) = split_at_pos(data, object_hash.len_in_bytes())        .ok_or(decode::Error::Corrupt(            "link extension too short to read share index checksum",        ))        .map(|(id, d)| (git_hash::ObjectId::from(id), d))?;     if data.is_empty() {        return Ok(Link {            shared_index_checksum: id,            bitmaps: None,        });    }     let (delete, data) =        git_bitmap::ewah::decode(data).map_err(|err| decode::Error::BitmapDecode { kind: "delete", err })?;    let (replace, data) =        git_bitmap::ewah::decode(data).map_err(|err| decode::Error::BitmapDecode { kind: "replace", err })?;     if !data.is_empty() {        return Err(decode::Error::Corrupt("garbage trailing link extension"));    }     Ok(Link {        shared_index_checksum: id,        bitmaps: Some(Bitmaps { delete, replace }),    })}