.\"
.\" Copyright (c) 2018 Stefan Sperling <stsp@openbsd.org>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd $Mdocdate$
.Dt GOT-REPOSITORY 5
.Os
.Sh NAME
.Nm got-repository
.Nd format of
.Xr got 1
repositories
.Sh DESCRIPTION
.Xr got 1
stores the history of tracked files in a repository which uses
the same on-disk format as
.Dq bare
repositories used by the Git version control system.
.Pp
The repository's core data model is a directed acyclic graph which
contains three types of objects as nodes.
Each object is identified by the SHA-1 hash calculated over the object's
header plus the content stored in the object.
The object header names the type of object in an ASCII string, which is
followed by a space, followed by the size of data in the object encoded
as an ASCII number string.
This header is terminated by a
.Sy NUL
character.
.Pp
The content of files tracked under version control is stored in objects
of type
.Em blob .
.Pp
A
.Em tree
object points to any number of such blobs, and also to other trees
in order to form a hierarchy of files and directories.
.Pp
A
.Em commit
object points to the root element of one tree, and thus records the
state of this entire tree as a snapshot.
Commit objects are chained together and thus form a line of history
of snapshots.
A given commit can be suceeded by an arbitrary number of subsequent
commits, such that diverging lines of version control history, known as
.Em branches ,
can be represented.
A commit which preceeds another commit is referred to as that other commit's
.Em parent commit .
A commit with multiple parents reunites diverged lines of history and is
known as a
.Em merge commit .
While the data model allows for commits with an arbitrary number of
parent commits,
.Xr got 1
restricts all commits to at most 2 parents in order to discourage chaotic
branching and merging practices.
.Pp
When stored on disk, all objects are compressed with
.Xr deflate 3 .
Mulitple objects may be stored together in a
.Em pack file
which provides for deltification of object content.
.Sh FILES
.Bl -tag -width /etc/rpc -compact
.It Pa HEAD
.It Pa ORIG_HEAD
.It Pa FETCH_HEAD
.It Pa branches/
.It Pa config
.It Pa description
.It Pa hooks/
.It Pa index
.It Pa info
.It Pa logs/
.It Pa objects/
.It Pa packed-refs
.It Pa refs/
.El
.Sh SEE ALSO
.Xr git 1 ,
.Xr got 1 ,
.Xr deflate 3 ,
.Xr got-worktree 5
.Sh HISTORY
The Git repository format was conceived by Linus Torvalds in 2005.