An easy way to figure out whether I have access to a resource would be nice

[hakanai]

I am looking for a way to do something like isWritable() for a DavResource. I know there is partial support for ACLs, but the logic to determine whether an ACL matches my own principals is non-trivial and I'm not even certain how I'm supposed to fetch my own principals.

The best lead that I have on implementing this myself is to fetch the "D:current-user-privilege-set" property like so:

private static final QName CURRENT_USER_PRIVILEGE_SET = new QName("DAV:", "current-user-privilege-set", "DAV");

// ...

        DavResource resource  = sardine.list(uri.toString(), 0, ImmutableSet.of(CURRENT_USER_PRIVILEGE_SET)).get(0);
        String result = resource.getCustomPropsNS().get(CURRENT_USER_PRIVILEGE_SET);

But result always comes out as whitespace. I think that this is because the "D:current-user-privilege-set" property's value is an element, not text content.

Example from the RFC shows what it looks like:

<?xml version="1.0" encoding="utf-8" ?> 
<D:multistatus xmlns:D="DAV:">  
  <D:response>  
  <D:href>http://www.example.com/papers/</D:href> 
  <D:propstat> 
    <D:prop> 
      <D:current-user-privilege-set> 
        <D:privilege><D:read/></D:privilege> 
      </D:current-user-privilege-set> 
    </D:prop> 
    <D:status>HTTP/1.1 200 OK</D:status> 
  </D:propstat> 
  </D:response> 
</D:multistatus> 

So I guess this property is of type Privilege, which Sardine already has a model for, but isn't entirely obvious how I can get Sardine to parse the XML to give me an instance of Privilege instead of String, for a custom property value.