Re: [Dar-support] Request: Dar to preserve CreateTime on OS X

[John B T. <jb...@gm...>]

ok, I understand it will take a while.  In your bug-tracker, I would
rate the severity high, as this is a gating factor for me (and
probably many others) to use Dar on OS X.  For thousands of files
going back 20+ years, I simply cannot rely on a catalog that will lose
their history.

I figured the Mac extensions to get/setattrlist are not fully portable
 (at least it's easier than hooking dar into the OS X Cocoa/Carbon
APIs !)   CreateTime is actually also present on several other
OS/Filesytems: e.g. BtrFS, ZFS, ext4, NTFS, UDF, ISO9660, even some
versions of FAT apparently...
(see http://en.wikipedia.org/wiki/Comparison_of_file_systems)
I think it's reasonable for Dar to have platform-specific code as
necessary, rather than be limited to the least common denominator.

I thought the harder issue might be how to store the CreateTime in
Dar, which will require a catalog change?  Or maybe Dar already has
some catalog extension mechanism built-in?  If not, I was thinking
it's ok to store CreateTime as a special-named/handled EA -- although
(very slightly) risky, due to the potential for name collision if
there already was an EA with whatever name DAR uses internally.  I
judge that risk acceptable if it means getting CreateTime support
sooner, and maintaining compatibility with historic dar catalogs.

In the medium- to long-term, it would be good to see the Dar catalog
extendable to handle new types of metadata in existing and future
filesystems.  Possibly the existing EA mechanism, with a dedicated
dar.xxx.yyy  EA tree would suffice for this, as mentioned above.  Then
the darEAs would get specially handled and not appear/count as actual
EAs.

-- jbthiel