On Dec 22, 2006, at 15:42 UTC, Arnaud Nicolet wrote:

> I recently discovered that the "visible" property of a file in a  
> virtual volume cannot be set (I set f.visible=false and, when I check
> again, the property stays on true). Same thing apply to the locked  
> property.

True, the virtual filesystem, doesn't support that metadata.  (Of
course there's nothing that could be done with such metadata either,
except to read it back... so I guess you could make up your own place
to store this info, e.g. in a special file like OS X does for Finder
data.)

> On the other hand, I can change the name of the file and  
> its MacType, that's all I tried. So it appears that some properties  
> are not applicable to files in virtual volumes.

Right, or more generally: different file systems support different
metadata and other behaviors.  Some are case-sensitive, some are not;
some support a full Unix permissions model while others do not; some
have aliases and others don't; some are multi-forked and others are
single-forked; etc.

The virtual file system supports name and type codes, but does not
support creator codes, aliases, locked/visible bits, Unix permissions,
resource forks, etc.  It's also case-insensitive IIRC.  Again IIRC, it
supports creation and modification dates.  It doesn't support any
special file formats though; SaveAsPicture, OpenAsSound, etc., will not
work with it (since those formats are supported by the OS, but there
isn't much of an OS associated with a virtual volume).
 
> Files in a virtual volumes seems a bit paradoxical for me. Some  
> properties must exist (name, or directory, for example), some don't  
> have to (e.g ResourceForkLength) and some are, at the moment,  
> indeterminate (visible, creation date, modification date, locked,  
> etc. ).

I'm not sure what you mean by that.  There's nothing indeterminate
about it; the VFS doesn't support resource forks any more than Windows
does, nor does it support the metadata noted above.

> Since the "alias" property is only applicable on Macs, where  
> the file contains at least an "alis" resource, since no resources are
> allowed in a virtual volume, the "alias" property is certainly not  
> useable.

Right.

> Is there a list available somewhere which shows what properties are  
> supported for files in virtual volumes? Apparently, there is no  
> information in the Language Reference.

Not entirely true; the VirtualVolume entry says:

"Filenames can be up to 223 bytes long. Paths are not supported, but
directories are (e.g., create a virtual directory with the
CreateAsFolder method of the FolderItem class, and navigate to it with
the Child or Item methods of this class). The virtual file system
supports four-byte type codes (accessed via f.MacType), but does not
support creator codes."

However, I agree that this isn't a complete spec.  A feature request to
have this fleshed out a bit seems appropriate to me.

Best,
- Joe

--
Joe Strout -- [EMAIL PROTECTED]
Verified Express, LLC     "Making the Internet a Better Place"
http://www.verex.com/

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