use std::{    fmt::{Debug, Formatter},    path::Path,}; use crate::{    file::{self, commit::Commit, COMMIT_DATA_ENTRY_SIZE_SANS_HASH},    File,}; /// Accessimpl File {    /// The number of base graphs that this file depends on.    pub fn base_graph_count(&self) -> u8 {        self.base_graph_count    }     /// Returns the commit data for the commit located at the given lexicographical position.    ///    /// `pos` must range from 0 to `self.num_commits()`.    ///    /// # Panics    ///    /// Panics if `pos` is out of bounds.    pub fn commit_at(&self, pos: file::Position) -> Commit<'_> {        Commit::new(self, pos)    }     /// The kind of hash used in this File.    ///    /// Note that it is always conforming to the hash used in the owning repository.    pub fn object_hash(&self) -> gix_hash::Kind {        self.object_hash    }     /// Returns an object id at the given index in our list of (sorted) hashes.    /// The position ranges from 0 to `self.num_commits()`    // copied from gix-odb/src/pack/index/ext    pub fn id_at(&self, pos: file::Position) -> &gix_hash::oid {        assert!(            pos.0 < self.num_commits(),            "expected lexicographical position less than {}, got {}",            self.num_commits(),            pos.0        );        let pos: usize = pos            .0            .try_into()            .expect("an architecture able to hold 32 bits of integer");        let start = self.oid_lookup_offset + (pos * self.hash_len);        gix_hash::oid::from_bytes_unchecked(&self.data[start..][..self.hash_len])    }     /// Return an iterator over all object hashes stored in the base graph.    pub fn iter_base_graph_ids(&self) -> impl Iterator<Item = &gix_hash::oid> {        let start = self.base_graphs_list_offset.unwrap_or(0);        let base_graphs_list = &self.data[start..][..self.hash_len * usize::from(self.base_graph_count)];        base_graphs_list            .chunks_exact(self.hash_len)            .map(gix_hash::oid::from_bytes_unchecked)    }     /// return an iterator over all commits in this file.    pub fn iter_commits(&self) -> impl Iterator<Item = Commit<'_>> {        (0..self.num_commits()).map(move |i| self.commit_at(file::Position(i)))    }     /// Return an iterator over all object hashes stored in this file.    pub fn iter_ids(&self) -> impl Iterator<Item = &gix_hash::oid> {        (0..self.num_commits()).map(move |i| self.id_at(file::Position(i)))    }     /// Translate the given object hash to its position within this file, if present.    // copied from gix-odb/src/pack/index/ext    pub fn lookup(&self, id: impl AsRef<gix_hash::oid>) -> Option<file::Position> {        self.lookup_inner(id.as_ref())    }     fn lookup_inner(&self, id: &gix_hash::oid) -> Option<file::Position> {        let first_byte = usize::from(id.first_byte());        let mut upper_bound = self.fan[first_byte];        let mut lower_bound = if first_byte != 0 { self.fan[first_byte - 1] } else { 0 };         while lower_bound < upper_bound {            let mid = (lower_bound + upper_bound) / 2;            let mid_sha = self.id_at(file::Position(mid));             use std::cmp::Ordering::*;            match id.cmp(mid_sha) {                Less => upper_bound = mid,                Equal => return Some(file::Position(mid)),                Greater => lower_bound = mid + 1,            }        }        None    }     /// Returns the number of commits in this graph file.    ///    /// The maximum valid `file::Position` that can be used with this file is one less than    /// `num_commits()`.    pub fn num_commits(&self) -> u32 {        self.fan[255]    }     /// Returns the path to this file.    pub fn path(&self) -> &Path {        &self.path    }} impl File {    /// Returns the byte slice for the given commit in this file's Commit Data (CDAT) chunk.    pub(crate) fn commit_data_bytes(&self, pos: file::Position) -> &[u8] {        assert!(            pos.0 < self.num_commits(),            "expected lexicographical position less than {}, got {}",            self.num_commits(),            pos.0        );        let pos: usize = pos            .0            .try_into()            .expect("an architecture able to hold 32 bits of integer");        let entry_size = self.hash_len + COMMIT_DATA_ENTRY_SIZE_SANS_HASH;        let start = self.commit_data_offset + (pos * entry_size);        &self.data[start..][..entry_size]    }     /// Returns the byte slice for this file's entire Extra Edge List (EDGE) chunk.    pub(crate) fn extra_edges_data(&self) -> Option<&[u8]> {        Some(&self.data[self.extra_edges_list_range.clone()?])    }} impl Debug for File {    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {        write!(f, r#"File("{:?}")"#, self.path.display())    }}