RFR 8213031: (zipfs) Add support for POSIX file permissions

[Langer, Christoph]

Hi Alan,

thanks for taking a first look into this new edition.

> I think the javadoc changes will need a few iterations but we can get to
> that once some of the finer details are sorted out. For example, "Posix
> Support" isn't quite right as this is about optional support for the
> POSIX view of file attributes rather than complete support for POSIX.

Ok.

> Also the "Zip" view of file attributes will need to be fleshed out more
> (the view name for example).

I don't know if that's really necessary as the "Zip" view currently is internal to jdk.zips and I don't propose to export it.

> I'm not sure about using ${user.name} and "<zipfs_default>" as default.
> Have you looked at using the zip file owner/group (or owner/owner on
> Windows) as the default? 

Hm, I guess for Unix that'd be ok. But how would I get to the owner of a file in Window's default file system?

> Also just wondering if 777 might be more
> appropriate (maybe you have a reason for choosing 660?). It might be
> useful to see what Linux, macOS and other operating systems do when
> mounting a FAT file system.

I implemented 640, but it was just chosen without much thinking. I can agree to 777.

> Did you consider using the string representation of the user, group and
> permissions in the configuration properties? The zip file system
> provider could support both of course. String might make it a bit easier
> to create the map of configuration properties when creating the file
> system e.g
> Map.of("enablePosixPermissions", "true", "defaultOwner", "joe",
> "defaultPermissions", "rw-rw---");

Sounds like a good and feasible idea.

I'll try to address these points in a next iteration.

Best regards
Christoph