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Monorepo for Tangled
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use knot_types::{ObjectCount, Oid};
use crate::error::GitError;use crate::objects::{Haves, Wants};use crate::repo::Repo;
mod bitset;mod midx;mod reader;mod revindex;mod writer;
use bitset::Bitset;use revindex::{Order, OrderTable};
knot_types::scalar_newtype! { pub(crate) struct BitPosition(u32); pub(crate) struct IndexPosition(u32) => ordered; pub(crate) struct BitmapEntryOffset(u64);}
pub fn write_bitmap(repo: &Repo, pack_idx: &Path) -> Result<bool, GitError> { writer::write(repo, pack_idx)}
pub fn write_midx_bitmap(repo: &Repo) -> Result<bool, GitError> { midx::write(repo)}
pub fn reachable_via_bitmap( repo: &Repo, wants: Wants<'_>, haves: Haves<'_>,) -> Result<Option<Vec<Oid>>, GitError> { if let Some((_, found)) = single_pack(repo, wants, haves)? { return Ok(Some(found)); } midx::reachable(repo, wants, haves)}
fn single_pack( repo: &Repo, wants: Wants<'_>, haves: Haves<'_>,) -> Result<Option<(ObjectCount, Vec<Oid>)>, GitError> { let kind = repo.object_format().kind(); let Some(pack_idx) = bitmapped_pack(&repo.objects_dir()) else { return Ok(None); }; let Ok(bytes) = std::fs::read(pack_idx.with_extension("bitmap")) else { return Ok(None); }; let index = gix_pack::index::File::at(&pack_idx, kind) .map_err(|error| GitError::Backend(format!("open pack index: {error}")))?; let rev = OrderTable::from_index(&index); let count = rev.len(); let maps = reader::parse(&bytes, kind, count)?; Ok(resolve(repo, &rev, &maps, wants, haves)? .map(|reachable| (ObjectCount::new(count), reachable)))}
pub(super) fn resolve( repo: &Repo, rev: &impl Order, maps: &reader::Bitmaps<'_>, wants: Wants<'_>, haves: Haves<'_>,) -> Result<Option<Vec<Oid>>, GitError> { let (Some(want), Some(have)) = ( accumulate(repo, rev, maps, wants.as_slice())?, accumulate(repo, rev, maps, haves.as_slice())?, ) else { return Ok(None); }; let reachable = want .difference_indices(&have) .map(|bit| rev.oid_at_bit(bit)) .collect(); Ok(Some(reachable))}
pub fn verbatim_clone_pack( repo: &Repo, wants: Wants<'_>,) -> Result<Option<std::fs::File>, GitError> { let Some(pack_idx) = bitmapped_pack(&repo.objects_dir()) else { return Ok(None); }; let Some((num_objects, reachable)) = single_pack(repo, wants, Haves::new(&[]))? else { return Ok(None); }; if ObjectCount::new(reachable.len()) != num_objects { return Ok(None); } Ok(std::fs::File::open(pack_idx.with_extension("pack")).ok())}
fn bitmapped_pack(objects_dir: &Path) -> Option<PathBuf> { let pack_dir = objects_dir.join("pack"); let mut idxs: Vec<PathBuf> = std::fs::read_dir(&pack_dir) .ok()? .filter_map(Result::ok) .map(|entry| entry.path()) .filter(|path| path.extension().is_some_and(|ext| ext == "idx")) .collect(); idxs.sort(); idxs.into_iter() .find(|idx| idx.with_extension("bitmap").exists())}
fn accumulate( repo: &Repo, rev: &impl Order, maps: &reader::Bitmaps<'_>, oids: &[Oid],) -> Result<Option<Bitset>, GitError> { oids.iter() .try_fold(Some(Bitset::zeros(rev.len())), |acc, oid| { let Some(mut acc) = acc else { return Ok(None); }; match contribution(repo, rev, maps, *oid)? { Some(part) => { acc.union_with(&part); Ok(Some(acc)) } None => Ok(None), } })}
fn contribution( repo: &Repo, rev: &impl Order, maps: &reader::Bitmaps<'_>, oid: Oid,) -> Result<Option<Bitset>, GitError> { let Some((commit, tags)) = peel_commit_chain(repo, oid) else { return Ok(None); }; let Some(position) = rev.index_of(commit) else { return Ok(None); }; let Some(base) = maps.bitmap(position)? else { return Ok(None); }; let bits = tags.iter().try_fold(base, |mut bits, tag| { let position = rev.index_of(*tag)?; bits.set(rev.bit_at_index(position)); Some(bits) }); Ok(bits)}
fn peel_commit_chain(repo: &Repo, oid: Oid) -> Option<(Oid, Vec<Oid>)> { let object = repo.git().find_object(oid.object_id()).ok()?; match object.kind { gix::object::Kind::Commit => Some((oid, Vec::new())), gix::object::Kind::Tag => { let target = object.try_into_tag().ok()?.target_id().ok()?.detach(); peel_commit_chain(repo, Oid::from(target)).map(|(commit, mut tags)| { tags.push(oid); (commit, tags) }) } _ => None, }}