#![allow(unused)] use std::path::{Path, PathBuf}; use memmap2::Mmap; use crate::{decode, extension, File, State}; mod error {     /// The error returned by [File::at()][super::File::at()].    #[derive(Debug, thiserror::Error)]    #[allow(missing_docs)]    pub enum Error {        #[error("An IO error occurred while opening the index")]        Io(#[from] std::io::Error),        #[error(transparent)]        Decode(#[from] crate::decode::Error),    }} pub use error::Error; /// Initializationimpl File {    /// Open an index file at `path` with `options`.    pub fn at(path: impl Into<PathBuf>, options: decode::Options) -> Result<Self, Error> {        let path = path.into();        let (data, mtime) = {            // SAFETY: we have to take the risk of somebody changing the file underneath. Git never writes into the same file.            let file = std::fs::File::open(&path)?;            #[allow(unsafe_code)]            let data = unsafe { Mmap::map(&file)? };            (data, filetime::FileTime::from_last_modification_time(&file.metadata()?))        };         let (state, checksum) = State::from_bytes(&data, mtime, options)?;        Ok(File { state, path, checksum })    }}