Struct PackBitmapWriter 

pub struct PackBitmapWriter { /* private fields */ }

Builder that assembles a reachability bitmap (.bitmap) for a pack.

The writer is constructed from the object layout of a pack (one ObjectType per object, in pack order) and the pack’s trailing checksum. Callers then register one selected commit per add_commit call, supplying the set of pack positions reachable from that commit. build/write produce a PackBitmapIndex / serialised .bitmap bytes matching git’s on-disk format (signature BITM, version 1).

Implementations

impl PackBitmapWriter

pub const FLAG_NONE: u8 = 0

OBJ_NONE selection flag: this commit’s bitmap is stored in full (no XOR compression against a previously selected commit). This is the only flag value this writer emits.

pub fn new( format: ObjectFormat, pack_checksum: ObjectId, object_types: &[ObjectType], ) -> Result<Self>

Creates a writer for a pack whose objects (in pack order) have the given ObjectTypes and whose trailing checksum is pack_checksum.

Returns an error if the pack contains more than u32::MAX objects, if pack_checksum’s format does not match format, or if any object type is not one of the four reachable git object kinds.

pub fn with_name_hash_cache(self, cache: Vec<u32>) -> Result<Self>

Attaches a name-hash cache (one u32 per object, in pack order). When set, the written bitmap advertises PackBitmapIndex::OPTION_HASH_CACHE and appends the cache after the bitmap entries, exactly as git does.

Returns an error if the cache length does not equal the object count.

pub fn add_commit( &mut self, commit_position: u32, commit_index_position: u32, reachable: &[u32], ) -> Result<()>

Registers a selected commit and the pack positions reachable from it.

commit_position is the pack-order position of the commit itself (the bit-number space); it must reference a commit object and is implicitly part of the reachable set. commit_index_position is the commit’s position in the oid-sorted pack index — this is what the on-disk entry records (upstream oid_pos); bits and entry positions live in different spaces. reachable lists the pack-order positions of every object reachable from the commit (it may include or omit commit_position; duplicates are fine). All positions must be in range. The commit’s full (non-XORed) bitmap is stored.

pub fn build(&self) -> Result<PackBitmapIndex>

Builds the in-memory PackBitmapIndex without serialising it.

The resulting index always advertises PackBitmapIndex::OPTION_FULL_DAG (the four type bitmaps fully cover the pack) and, when a name-hash cache was attached, PackBitmapIndex::OPTION_HASH_CACHE.

pub fn write(&self) -> Result<Vec<u8>>

Builds and serialises the .bitmap file, returning the on-disk bytes (including the trailing index checksum).

Trait Implementations

impl Clone for PackBitmapWriter

fn clone(&self) -> PackBitmapWriter

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for PackBitmapWriter

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.