use std::path::PathBuf; use crate::{    pack,    store::{compound, loose},}; /// Returned by [`compound::Store::at()`]#[derive(thiserror::Error, Debug)]#[allow(missing_docs)]pub enum Error {    #[error("The objects directory at '{0}' is not an accessible directory")]    Inaccessible(PathBuf),    #[error(transparent)]    Pack(#[from] pack::bundle::init::Error),    #[error(transparent)]    Alternate(#[from] Box<crate::alternate::Error>),} /// Instantiationimpl compound::Store {    /// Returns a compound database as initialized from the given git `objects_directory`, commonly `.git/objects`.    ///    /// Only loose and packed objects will be considered. See the [linked Db][crate::store::linked::Store] for a database with    /// support for _git alternates_, i.e. linking to other repositories.    pub fn at(objects_directory: impl Into<PathBuf>) -> Result<compound::Store, Error> {        let loose_objects = objects_directory.into();        if !loose_objects.is_dir() {            return Err(Error::Inaccessible(loose_objects));        }        let packs = match std::fs::read_dir(loose_objects.join("pack")) {            Ok(entries) => {                let mut packs_and_sizes = entries                    .filter_map(Result::ok)                    .filter_map(|e| e.metadata().map(|md| (e.path(), md)).ok())                    .filter(|(_, md)| md.file_type().is_file())                    .filter(|(p, _)| p.extension().unwrap_or_default() == "idx")                    // TODO: make this configurable, git for instance sorts by modification date                    //       https://github.com/libgit2/libgit2/blob/main/src/odb_pack.c#L41-L158                    .map(|(p, md)| pack::Bundle::at(p).map(|b| (b, md.len())))                    .collect::<Result<Vec<_>, _>>()?;                packs_and_sizes.sort_by_key(|e| e.1);                packs_and_sizes.into_iter().rev().map(|(b, _)| b).collect()            }            Err(_) => Vec::new(),        };         Ok(compound::Store {            loose: loose::Store::at(loose_objects),            bundles: packs,        })    }}