use bstr::BString;use smallvec::SmallVec; /// The size of the smallest possible extension, which is no more than a signature and a 0 indicating its size.pub const MIN_SIZE: usize = 4 /* signature */ + 4 /* size */; /// The kind of index extension.pub type Signature = [u8; 4]; /// An iterator over the data of index extensions.pub struct Iter<'a> {    data: &'a [u8],    /// The amount of consumed bytes as seen from our internal data pointer. Useful to continue where the iterator left off.    pub consumed: usize,} /// A structure to associate object ids of a tree with sections in the index entries list.////// It allows to more quickly build trees by avoiding as it can quickly re-use portions of the index and its associated tree ids/// if there was no change to them. Portions of this tree are invalidated as the index is changed.#[derive(PartialEq, Eq, Clone, Debug)]pub struct Tree {    /// The name of the tree/directory, or empty if it's the root tree.    pub name: SmallVec<[u8; 23]>,    /// The id of the directory tree of the associated tree object.    pub id: git_hash::ObjectId,    /// The amount of non-tree items in this directory tree, including sub-trees, recursively.    /// The value of the top-level tree is thus equal to the value of the total amount of entries.    /// If `None`, the tree is considered invalid and needs to be refreshed    pub num_entries: Option<u32>,    /// The child-trees below the current tree.    pub children: Vec<Tree>,} /// The link extension to track a shared index.#[derive(Clone)]pub struct Link {    /// The checksum of the shared index as last seen.    pub shared_index_checksum: git_hash::ObjectId,    /// Bitmaps to tell us which entries to delete or replace.    pub bitmaps: Option<link::Bitmaps>,} /// The extension for untracked files.#[allow(dead_code)]#[derive(Clone)]pub struct UntrackedCache {    /// Something identifying the location and machine that this cache is for.    /// Should the repository be copied to a different machine, the entire cache can immediately be invalidated.    identifier: BString,    /// Stat for the .git/info/exclude file    info_exclude: Option<untracked_cache::OidStat>,    /// Stat for the `core.excludesfile`    excludes_file: Option<untracked_cache::OidStat>,    /// Usually `.gitignore`    exclude_filename_per_dir: BString,    dir_flags: u32,     /// A list of directories and sub-directories, with `directories[0]` being the root.    directories: Vec<untracked_cache::Directory>,} /// The extension for keeping state on recent information provided by the filesystem monitor.#[allow(dead_code)]#[derive(Clone)]pub struct FsMonitor {    token: fs_monitor::Token,    /// if a bit is true, the respective entry is NOT valid as per the fs monitor.    entry_dirty: git_bitmap::ewah::Vec,} mod iter; pub(crate) mod fs_monitor; ///pub mod decode; ///pub mod tree; ///pub mod end_of_index_entry; pub(crate) mod index_entry_offset_table; ///pub mod link; pub(crate) mod resolve_undo; ///pub mod untracked_cache; ///pub mod sparse;