Re: [PATCH 0/6] Introduce commit notes

[Johannes Schindelin <Johannes.Schindelin@gmx.de>]

Hi,

On Mon, 16 Jul 2007, Junio C Hamano wrote:

> Andy Parkins <andyparkins@gmail.com> writes:
> 
> > On Monday 2007 July 16, Johannes Schindelin wrote:
> >
> >> The biggest obstacle was a thinko about the scalability.  Tree 
> >> objects take free form name entries, and therefore a binary search by 
> >> name is not possible.
> >
> > I might be misunderstanding, but in the case of the notes tree objects 
> > isn't it true that the name entries aren't free form, but are 
> > guaranteed to be of a fixed length form:
> >
> >   XX/XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
> >
> > In which case you can binary search?
> 
> Hmph, you are right.  In this sequence:
> 
> 	hex = sha1_to_hex(commit->object.sha1);
> 	snprintf(name, sizeof(name), "%s:%.*s/%.*s",
> 			notes_ref_name, 2, hex, 38, hex + 2);
> 	if (get_sha1(name, sha1))
> 		return;
> 
> Instead, we could read the tree object by hand in the commit that is 
> referenced by notes_ref_name, which has uniform two letter names for 
> subtrees which can be binary searched, open the tree for that entry, 
> again by hand, and do another binary search because that tree has 
> uniform 38-letter names.  That certainly could be done.
> 
> Sounds like a "fun" project for some definition of the word.

I disagree.  One disadvantage to using tree objects is that it is much 
easier to have pilot errors.  You could even make a new working tree 
checking out refs/notes/commits and change/add/remove files.

Ciao,
Dscho