gazagnaire.org
Git object storage and pack files for Eio
1(* Copyright (c) 2013-2017 Thomas Gazagnaire <thomas@gazagnaire.org>
2 Copyright (c) 2017-2024 Romain Calascibetta <romain.calascibetta@gmail.com>
3 Copyright (c) 2024-2026 Thomas Gazagnaire <thomas@gazagnaire.org>
4
5 Permission to use, copy, modify, and distribute this software for any
6 purpose with or without fee is hereby granted, provided that the above
7 copyright notice and this permission notice appear in all copies.
8
9 THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. *)
16
17(** Git object hashes (SHA-1 or SHA-256). *)
18
19type t = Digestif.SHA1.t
20
21let digest_size = Digestif.SHA1.digest_size
22let pp = Digestif.SHA1.pp
23let equal = Digestif.SHA1.equal
24let compare = Digestif.SHA1.unsafe_compare
25
26let of_raw_string s =
27 if String.length s <> digest_size then
28 invalid_arg "Hash.of_raw_string: invalid length";
29 Digestif.SHA1.of_raw_string s
30
31let to_raw_string = Digestif.SHA1.to_raw_string
32let of_hex s = Digestif.SHA1.of_hex s
33let to_hex t = Digestif.SHA1.to_hex t
34
35let null =
36 let s = String.make digest_size '\x00' in
37 of_raw_string s
38
39let v t = Hashtbl.hash (to_raw_string t)
40
41module Set = Set.Make (struct
42 type nonrec t = t
43
44 let compare = compare
45end)
46
47module Map = Map.Make (struct
48 type nonrec t = t
49
50 let compare = compare
51end)
52
53(** Compute the hash of a git object. *)
54let digest ~kind ~length contents =
55 let kind_str =
56 match kind with
57 | `Blob -> "blob"
58 | `Tree -> "tree"
59 | `Commit -> "commit"
60 | `Tag -> "tag"
61 in
62 let header = Fmt.str "%s %d\x00" kind_str length in
63 let ctx = Digestif.SHA1.empty in
64 let ctx = Digestif.SHA1.feed_string ctx header in
65 let ctx = Digestif.SHA1.feed_string ctx contents in
66 Digestif.SHA1.get ctx
67
68let digest_string ~kind s = digest ~kind ~length:(String.length s) s