Re: git over webdav: what can I do for improving http-push ?

From: Martin Langhoff <martin.langhoff@gmail.com>
Date: Jan 3, 2008, 23:54 UTC
Message-ID: <46a038f90801031554j6218f08cl6c9608b24e1675f8@mail.gmail.com>
In-Reply-To: <20080103211521.GA4225@efreet.light.src>

On Jan 4, 2008 10:15 AM, Jan Hudec <bulb@ucw.cz> wrote:

> Now to keep it stateless, I thought that:

...

> This would guarantee, that when you want n revisions, you make at most
> log2(n) requests and get at most 2*n revisions (well, the requests are for

That is still a lot! How about, for each ref

 - Client sends a POST listing the ref and the latest related commit
it has that the server is likely to have (from origin/heads/<ref>).
Optionally, it can provide a blacklist of <treeish> (where every
object refered is known) and blob sha1s.
 - Server sends the new sha1 of the ref, and a thin pack that covers the changes
 - The client can disconnect to stop the transaction. For example --
if it sees the sha1 of a huge object that it already has. It can
re-request, with a blacklist.

A good number of objects will be sent unnecesarily - with no option to the client to say "I have this" - but by using the hint of letting the server know we have origin/heads/<ref> I suspect that it will be minimal.

Also:
 - It will probably be useful to list all the refs the client knows
from that server in the request.
 - If the ref has changed with a non-fast-forward, the server needs to
say so, and provide a listing of the commits. As soon as the client
spots a common commit, it can close the connection -- it now knows
what ref to tell the server about in a subsequent command.

This way, you ideally have 1 request per ref, 2 if it has been rebased/rewound. This can probably get reorganised to do several refs in one request.

cheers,