Re: metastore

From: David Härdeman <david@hardeman.nu>
Date: Oct 2, 2007, 21:15 UTC
Message-ID: <20071002211518.GA10445@hardeman.nu>
In-Reply-To: <85lkalz3iv.fsf@lola.goethe.zz>

On Tue, Oct 02, 2007 at 10:04:56PM +0200, David Kastrup wrote:

Show 21 quoted lines

>David Härdeman <david@hardeman.nu> writes:
>
>> On Tue, Oct 02, 2007 at 08:53:01PM +0100, martin f krafft wrote:
>>>also sprach David Härdeman <david@hardeman.nu> [2007.09.19.2016 +0100]:
>>>> But I agree, if any changes were made to git, I'd advocate adding
>>>> arbitrary attributes to files (much like xattrs) in name=value
>>>> pairs, then any extended metadata could be stored in those
>>>> attributes and external scripts/tools could use them in some way
>>>> that makes sense...and also make sure to only update them when it
>>>> makes sense.
>>>
>>>So where would those metdata be stored in your opinion?
>>
>> I'm not sufficiently versed in the internals of git to have an
>> informed opinion :)
>
>I think we have something like a length count for file names in index
>and/or tree.  We could just put the (sorted) attributes after a NUL
>byte in the file name and include them in the count.  It would also
>make those artificially longer file names work more or less when
>sorting them for deltification.

Or perhaps the index format could be extended to include a new field for value=name pairs instead of overloading the name field.

But as I said, I have no idea how feasible it would be to change git to support another arbitrary length field in the index/tree file.

>However, this requires implementing _policies_: it must be possible to
>specify per repository exactly what will and what won't get tracked,
>or one will get conflicts that are not necessary or appropriate.

I think the opposite approach would be better. Let git provide set/get/delete attribute operations and leave it at that. Then external programs can do what they want with that data and add/remove/modify tags as necessary (and also include the smarts to not, e.g. remove the permissions on all files if the git repo is checked out to a FAT fs).

-- 
David Härdeman