Re: Tracking OpenOffice files/other compressed files with Git

[Johannes Sixt <j.sixt@viscovery.net>]

[please reply to all and keep the Cc list.]

Sergio schrieb:
> Johannes Sixt <j.sixt <at> viscovery.net> writes:
> 
>> Peter Krefting schrieb:
>>> Since OpenOffice doucuments are just zipped xml files, I wondered how
>>> difficult it would be to create some hooks/hack git to track the files
>>> inside the archives instead?
>> You could write a "clean" filter that "recompresses" the archive with
>> level 0 upon git-add.
...
> It could be possible to write a clean filter to uncompress before commit.
> However there is a trick with the complementary smudge filter to be used at
> checkout. If you do not smudge properly, git always shows the file as changed
> wrt the index.  Smudging correctly would mean using the very same compression
> ratio and compress method that OO uses, which can be a little tricky. I have
> tried using the zip binary both in the clean and the smudge phases and it does
> not work nicely. The smudged file is always different from the original one. One
> should probably work at a lower level to have a finer control on what is
> happening (libzip) and prepend to the uncompressed file the compression
> parameters to be restored on smudging.

You don't need to smudge the OOo file on checkout iff OOo can read a file
that is "compressed" at level 0.

A file that you have just 'git add'ed must not show up as dirty even if it
was processed by a "clean" filter. If it does, then this indicates a bug
in git, and not that a corresponding "smudge" filter is missing or
misbehaves. Yes, I have observed this with my own "clean" filter some time
ago, but I have not yet tried hard enough to find a reproducible test case.

> The bigger issue is however that the clean/smudge thing can be really slow when
> dealing with large OO files.

True indeed.

-- Hannes