Re: How can i write a new protocol for git

From: Shawn O. Pearce <spearce@spearce.org>
Date: Sep 5, 2008, 14:52 UTC
Message-ID: <20080905145246.GA20537@spearce.org>
In-Reply-To: <20080905094746.GA26820@glandium.org>

Mike Hommey <mh@glandium.org> wrote:

Show 7 quoted lines

> On Fri, Sep 05, 2008 at 05:22:57PM +0800, Sky Patrick wrote:
> > 
> > If i want to write a new protocol for file transfer and would like to
> > to integrate it with git. Is it possible and easy to integrate it ?
> > Currently, i know that jgit may achieve it, but it is a Java
> > implementation and may not work with git command line program that
> > written in C.

Writing a dumb protocol support isn't difficult in JGit due to the
abstractions in place.  Its a little harder in C Git, unless Mike
(or someone else) can abstract out the cURL library usage and make
it more flexible.  Though these days cURL supports just about any
file transfer protocol known.

> First, it would depend if you need this new protocol to be a dumb
> protocol (like rsync and http) or "native" (git or ssh).

Writing a smart protocol is a PITA. Look at the smart HTTP effort I am trying to do. OK, I'm not spending a whole lot of time on it, but its a damn difficult thing to do well, and to keep simple enough that it can be described and reimplemented. Otherwise we have another that-thing-before-Git on our hands.

> I've been meaning to refactor the dumb protocol "stack" for a while, but
> haven't gone much further than ideas in my mind (i.e. no code). I also
> have some start of http code recfactoring, that is waiting for this dumb
> protocol rework to be completed.

Yea. One reason why I'm doing the smart HTTP effort prototype in JGit is because the C code structure makes this harder to implement without first going through a number of refactorings. Though for the smart HTTP stuff I really need to refactor fetch-pack/send-pack and upload-pack/receive-pack, not the dumb walkers.

-- 
Shawn.