use crate::pack::data;use filebuffer::FileBuffer;use git_object::SHA1_SIZE;use std::{convert::TryFrom, convert::TryInto, path::Path}; /// Instantiationimpl data::File {    /// Try opening a data file at the given `path`.    pub fn at(path: impl AsRef<Path>) -> Result<data::File, data::parse::Error> {        data::File::try_from(path.as_ref())    }} impl TryFrom<&Path> for data::File {    type Error = data::parse::Error;     /// Try opening a data file at the given `path`.    fn try_from(path: &Path) -> Result<Self, Self::Error> {        use data::parse::N32_SIZE;         let data = FileBuffer::open(path).map_err(|e| data::parse::Error::Io {            source: e,            path: path.to_owned(),        })?;        let pack_len = data.len();        if pack_len < N32_SIZE * 3 + SHA1_SIZE {            return Err(data::parse::Error::Corrupt(format!(                "Pack data of size {} is too small for even an empty pack",                pack_len            )));        }        let (kind, num_objects) =            data::parse::header(&data[..12].try_into().expect("enough data after previous check"))?;        Ok(data::File {            data,            path: path.to_owned(),            version: kind,            num_objects,        })    }}