[mbackup-devel] tar..

[James O'K. <jo...@mi...>]

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.

Does that make sense?

-james