Module pack 

Pack file format — many objects in one file, with a hash→offset index.

A pack is written by lit gc and read back through ObjectStore, which consults packs whenever a hash has no loose object on disk. Both sides live here so the format is defined in one place: a reader and a writer that drift apart is how packed objects become unreadable.

Layout, all integers big-endian:

pack:  "LITP" version:u32 count:u32
       then per object: type:u8 uncompressed_len:u64 compressed_len:u64 zlib-data
index: "LITI" version:u32 count:u32
       then per object, sorted by hash: hash_len:u32 hash offset:u64 crc32:u32

Structs

PackIndexEntry

Pack index entry - maps hash to offset in pack

Constants

INDEX_MAGIC

Index magic header

INDEX_VERSION

Index version

PACK_MAGIC

Magic header for Lit pack files

PACK_VERSION

Pack version

Functions

load_all

Merge every pack index in packs_dir into one hash→(pack, offset) map.

load_pack_index

Load a pack index and build a hash→(pack_path, offset) map

packs_dir

The directory holding a repository’s packs.

read_pack_object

Read a single object from a pack file by offset

write_pack

Write a pack file from a set of objects.

write_pack_index

Write a pack index file