To read or write a commit graph we require access to the repository that
the graph should be read from or written for as well as the object
directory to derive its location. Instead of passing in these two bits
of information explicitly though, we pass in a `struct odb_source`,
which carries with it both of these pieces of information.
But ultimately, this is somewhat flawed as we now assume that the source
even has an on-disk representation, and furthermore we assume that the
commit graphs would live in ".git/objects/info". This is true for the
"files" backend, but it's not necessarily true for any other backend
that we may eventually want to introduce. So eventually, we'll want to
evolve the commit-graph subsystem to become agnostic of the backend's
layout and let the backend itself decide where to read a commit graph
from or where to write it to.
We're not there yet to do that switch, but the current design is already
causing issues for the intent of this patch series where we want to move
alternates into the "files" backend.
Convert the subsystem to take a repository plus an object directory path
instead. This unblocks moving around alternates, and it's also a step
in the right direction for moving commit graphs into the source in a
later series.
Note that we previously compared the `struct odb_source` pointers of two
commit graphs to figure out whether they were located in the same object
directory, whereas we now have to compare their paths. Callers may pass
in those paths in different forms though, for example relative to the
current working directory or as absolute paths. Convert the object
directory into an absolute path both when loading and when writing
commit graphs so that the comparisons become more robust.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Git - fast, scalable, distributed revision control system
Git is a fast, scalable, distributed revision control system with an
unusually rich command set that provides both high-level operations
and full access to internals.
Git is an Open Source project covered by the GNU General Public
License version 2 (some parts of it are under different licenses,
compatible with the GPLv2). It was originally written by Linus
Torvalds with help of a group of hackers around the net.
Please read the file INSTALL for installation instructions.
Many Git online resources are accessible from https://git-scm.com/
including full documentation and Git related tools.
See Documentation/gittutorial.adoc to get started, then see
Documentation/giteveryday.adoc for a useful minimum set of commands, and
Documentation/git-<commandname>.adoc for documentation of each command.
If git has been correctly installed, then the tutorial can also be
read with man gittutorial or git help tutorial, and the
documentation of each command with man git-<commandname> or git help <commandname>.
Those wishing to help with error message, usage and informational message
string translations (localization l10) should see po/README.md
(a po file is a Portable Object file that holds the translations).
Issues which are security relevant should be disclosed privately to
the Git Security mailing list git-security@googlegroups.com.
The maintainer frequently sends the "What's cooking" reports that
list the current status of various development topics to the mailing
list. The discussion following them give a good reference for
project status, development direction and remaining tasks.
The name "git" was given by Linus Torvalds when he wrote the very
first version. He described the tool as "the stupid content tracker"
and the name as (depending on your mood):
random three-letter combination that is pronounceable, and not
actually used by any common UNIX command. The fact that it is a
mispronunciation of "get" may or may not be relevant.
stupid. contemptible and despicable. simple. Take your pick from the
dictionary of slang.
"global information tracker": you're in a good mood, and it actually
works for you. Angels sing, and a light suddenly fills the room.
"goddamn idiotic truckload of sh*t": when it breaks
