8030048: (fs) Support UserDefinedFileAttributeView/extended attributes on OS X / HFS+

[JaniruTEC]

On 26/11/2020 18:01, Alan Bateman wrote:

> At this time, the attributes views that are supported is configured in 
> BsdFileSystem but it's okay for MacOSXFileSystem to augment this. 
> There isn't any issue using unsafe here but the interface to these 
> APIs involved memory outside of the heap then we'll need to study it 
> closely to make sure that it is robust.
>
> -Alan

My employer wrote a proof of concept that heavily utilizes the existing 
linux code to create a BSD implementation, which can be found here: 
https://github.com/skymatic/jdk/tree/feature/macos-xattr

We have a few questions now:
- Since BSD and Linux share so much code, we believe deduplication could 
be a reasonable matter. Should this be part of this PR or a second one? 
Is deduplication even a matter you wish us to pursue?
- The Linux implementation doesn't utilize newer java features. Which is 
the latest java version the BSD Implementation should utilize features 
of? Should the Linux version be updated as well? How does backporting 
affect this decision?
- At what point in time should the PR be created? Is communication over 
Mail or over the PR preferred?

Thanks for your time!
- Dominik