Re: Use case: GIT to manage transactions in a CMS?

From: Junio C Hamano <junkio@cox.net>
Date: Feb 17, 2006, 11:44 UTC
Message-ID: <7v7j7u43c2.fsf@assigned-by-dhcp.cox.net>
In-Reply-To: <43F5AF3C.5050507@itaapy.com>

"J. David Ibáñez" <jdavid@itaapy.com> writes:

> Maybe I could hack something, are there some docs explaining the
> internal format of git objects? or, where to look in the source to
> find this info?

The index file is mostly dealt with by read-cache.c (despite its name, it has both read and write routines). The easiest way to understand the tree object format is by reading write-tree.c.

But the format is the easiest part. You have to realize that this is a nontrivial task.

The merge algorithm assumes that it can detect a presense of directory by finding a blob under that. You need to teach 'read-tree -m' that sometimes there is an empty directory recorded in the index file. This is very important to avoid directory-file conflicts during the merge.

Tree object side is probably easier because we _can_ write an empty tree object, and presumably three tree-walker implementations (one used in read-tree and object layer, one in diff-tree and another in merge-tree) should all handle empty trees gracefully, but still its callers need to be verified.

> Another point, the application is written in Python, right now
> I have to open a shell to run the git commands.

I always have a shell open so it does not sound a big deal to me ;-).

Show 6 quoted lines

> It would be nice if the core functionality was implemented in a C
> library, then with a Python wrapper I could use git without going
> through the shell.
>
> Is this something to be expected? There will be a "libgit" sometime
> in the future?

Yes, read the list archive.

But not yet. The core level has been fluctuating quite a bit. The latest round being the object layer bookkeeping changes.