package git-unix
Install
Dune Dependency
Authors
Maintainers
Sources
sha256=5d614ae0404a2438c5cee98bf4aa64cee9980e2a382a437acd6ee65dcca6f4de
sha512=9a863552ad7fddfa37d92738dd1c793e888a3c544f97a7634aa9ed5cef1ca22db4e6bfa1908c58986af0bf1dcd665ba63308c1656e68397b7a87f1a09e94fe97
README.md.html
ocaml-git -- Git format and protocol in pure OCaml
Support for on-disk and in-memory Git stores. Can read and write all the Git objects: the usual blobs, trees, commits and tags but also the pack files, pack indexes and the index file (where the staging area lives - only for git-unix
package).
All the objects share a consistent API, and convenience functions are provided to manipulate the different objects. For instance, it is possible to make a pack file position independent (as the Zlib compression might change the relative offsets between the packed objects), to generate pack indexes from pack files, or to expand the filesystem of a given commit.
The library comes with some command-line tools called ogit-*
as a Proof-of-concept of the core library which shares a similar interface with git
, but where all operations are mapped to the API exposed by ocaml-git
(and hence using only OCaml code). However, these tools are not meant to be used. They are just examples of how to use ocaml-git
.
ocaml-git
wants to be a low-level library for irmin. By this fact, high-level processes such as a (patience) diff, git status
, etc. are not implemented.
As a MirageOS project, ocaml-git
is system agnostic. However, it provides a git-unix
package which uses UNIX syscall and it able to introspect a Git repository as you usually know. However, ocaml-git
handles only Git objects and it does not populate your filesystem as git
does.
For example, Git_unix.Sync.clone
does not give you files of your repository but synchronize your .git
with your repository.
The API documentation is available online.
Build, Install Instructions and Packages
To build and install the project, simply run:
$ opam install git
$ opam install git-unix
$ opam install git-mirage
Linking-trick
ocaml-git
uses 2 libraries with the linking-trick:
These libraries provide a C implementation and an OCaml implementation (mostly to be compatible with js_of_ocaml
). However, utop
or any a build-system such as ocamlbuild
are not able to choose between these implementations. So, you must explicitely choose one.
These libraries use virtual-library available with dune
. If your build-system is dune
, you should not have any problem about that where dune
is able to take the default implementation of these libraries.
What is supported
The loose object files can be read and written;
blobs (files)
trees (directories)
commits (revision history)
tags (annotated tags)
references (branch names)
The PACK files (collections of compressed loose objects using a binary-diff representation) and PACK indexes (indexes of pack files) can be read and written). The binary diff hunks are exposed using a high-level position-independent representation so that they can be manipulated more easily. Pack file can be created and is compressed.
The INDEX file (used as for managing the staging area) are fully supported. Which means that
git diff
andgit status
will work as expected on a repository created by the library. This feature is only available forgit-unix
when it needs to introspect a file-system.Cloning and fetching (using various options) are fully supported for the Git protocol, the smart-HTTP protocol and
git+ssh
. A subset of the protocol capabilities are implemented (mainlythin-pack
,ofs-delta
,side-band-64k
andallow-reachable-sha1-in-want
).Pushing is still experimental and needs more testing.
An abstraction for Git Store Is available. Various store implementations are available:
An in-memory implementation;
A unix filesystem implementation;
What is not supported
No server-side operations are currently supported.
No GC.
Updates, merge and rebase are not supported. Use irmin instead.
Performance
Performance is comparable to the Git tool.
Example
This utop
example must run into the ocaml-git
repository when the given path is .
.
# #require "checkseum.c" ;;
# #require "digestif.c" ;;
# #require "git-unix" ;;
# open Git_unix ;;
# module Search = Git.Search.Make(Store) ;;
# let read filename =
let open Lwt_result.Infix in
Store.v (Fpath.v ".") >>= fun t ->
Store.Ref.resolve t Store.Reference.master >>= fun head ->
let open Lwt.Infix in
Search.find t head (`Commit (`Path filename)) >>= function
| None -> Lwt.return (Error `Not_found)
| Some hash -> Store.read t hash
;;
val read : string list -> (Store.Value.t, Store.error) Lwt_result.t
# let pp =
let ok ppf = function
| Store.Value.Blob blob ->
Fmt.string ppf (Store.Value.Blob.to_string blob)
| _ -> Fmt.string ppf "#git-object" in
Fmt.result ~ok ~error:Store.pp_error
;;
val pp : (Store.Value.t, Store.error) Fmt.t
# Lwt_main.run Lwt.Infix.(read [ "README.md" ] >|= pp Fmt.stdout) ;;
ocaml-git -- Git format and protocol in pure OCaml
Support for on-disk and in-memory Git stores. Can read and write all
the Git objects: the usual blobs, trees, commits and tags but also
the pack files, pack indexes and the index file (where the staging area
lives).
[...]
License
MIT, see LICENSE.md file for its text.