6728842: File.setReadOnly does not make a directory read-only (win)

[Alan Bateman]

I need a reviewer for a change to java.io.File's setReadOnly and 
setWritable methods so that they don't change the DOS readonly attribute 
on directories (or folders as Windows calls them). These methods have 
never worked correctly for directories on Windows because the semantics 
of this attribute is different for directories (it determines if the 
directory can be deleted, not whether is is writable, and is used by 
Windows Explorer to determine if the directory is special, sending it 
off looking for a hidden Desktop.ini file). Early on in jdk7, the 
canWrite method was changed to ignore the readonly attribute on 
directories so changing the set* methods to ignore the attribute  
restores the status quo. I should say that changing the implementation 
has some risk. If it does cause problems they we may need to include a 
compatibility switch. The alternative to ignoring the readonly attribute 
is to insert a deny rule into the directory's DACL (when on NTFS) but 
that has a lot of potential to cause problems for end-users. As part of 
the change proposed here, the SetAccess test has been changed so that it 
no longer execs "ls -l" and this fixes another bug (6464744) where the 
test fails if the sticky bit is set. The webrev with the changes is here:
  http://cr.openjdk.java.net/~alanb/6728842/webrev/

Thanks,
Alan.