Re: [mbackup-devel] tar..

[Known H. N. R. <ni...@in...>]

>I'm looking at the source to gnu tar to see if there is a libtar. It seems
>there is one, but it's not well documented on how to use it. I also looked
>at the perl module and it seems that they do everything within perl. This
>would suggest that it's common for people to just reimpliment tar by
>following the file format (found in tar.h).
>The way I envision the module working is this.
>
>When it gets the first file to filter, it creates an archive and adds that
>file to it, and passes the work so far to the next module.
>When it gets the next file it acts as if it's appending it to the previous
>file and passes that along to the next filter.
>At some point it needs to end an archive and start a new one. The best
>time would be at the 2gig limit which is usually the filesize limit, but
>this should be configurable.
>
>We'll need to modify file_tar to keep track of when a file is inside some
>encoding. The current filtered_name won't due for very long. As a
>reminder, the way that the bzip filter works is it bzips the file and and
>changes filtered_named name to be foo.bz2. That works fine if everything
>is kept as small file size chunks. If we start globbing files into bigger
>units, we need a new way to encode this so that the indexing module can
>label the data.

Makes sense.

My thought was to use Gnutar or whatever directly as a pipe from
a file backend since it knows how to do tar in all its complexities
and thus relives us from having to reinvent the wheel.

as always,
nick

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