[saga-rg] open_flag and open_dir_flags

[Andre Merzky]

Quoting [Graeme Pound] (Mar 07 2006):
> 
> Andre,
> 
> Your change to the enumerations resolves the problem with respect to the 
>  Java bindings (using typesafe enumerations in Java 1.4.2). However you 
> may wish to do a sanity check that it is is possible/necessary to 
> inherit enumerations in other strongly typed languages (C++, C#).

For perl its a no-brainer.  For C++ we think its
unneccessary to inherit/extend flags, it seems simplier to
just redefine them.  In C they are global flags anyway I
guess.  For other languages I don't know.

Cheers, Andre.



> Graeme
> 
> 
> 
> 
> Andre Merzky wrote:
> >Hi Graeme, 
> >
> >Quoting [Graeme Pound] (Mar 01 2006):
> >>Hi,
> >>
> >>The relationship between the enumerations open_flag and open_dir_flags 
> >>in the various packages of the API is a little problematic.
> >>
> >>Graeme
> >>
> >>
> >> -3.35 How should interfaces inheriting from ns_directory and ns_entry 
> >>inherit/override the enumerations open_flag and open_dir_flags? The 
> >>methods of ns_directory open_dir() and open() will require the 
> >>enumerations defined in the name_space package (or sub-classes of these 
> >>enumerations).
> >
> >The reason for the various incarnations of open_flags are
> >that these have different meanings for the various classes.
> >We wanted to keep the ability to introdice a flag for
> >opening logical files (e.g. UseVersioning) which might not
> >needed or might have no meaning in namespace or for physical
> >files.  
> >
> >If that at the end should be too troublesome, a global
> >open_flag enum in name_space would probably do the trick -
> >we would need to verbosely specify what flags are to be
> >ignored in logical files or physical files though.
> >
> >However...
> >
> >
> >>With Java enumerations it would be possible to extend the original 
> >>enumerations by sub-classing, but it is not possible to not remove 
> >>fields. Unfortunately saga.logical_file.open_flags removes fields from 
> >>saga.name_space.open_flags.
> >
> >... that should have been cleaned.  I had a pending commit,
> >is in CVS now, which fixes that.  The flags are now:
> >
> >
> > +-------------------+-------------------+--------------------+
> > | name_space        | physical_file     |  logical_file      |
> > +-------------------+-------------------+--------------------+
> > | Unknown    =  -1, | Unknown    =  -1, |  Unknown    =  -1, |
> > | Create     =   1, | Create     =   1, |  Create     =   1, |
> > | Excl       =   2, | Excl       =   2, |  Excl       =   2, |
> > | Lock       =   4  | Lock       =   4, |  Lock       =   4, |
> > |                   | Truncate   =   8, |  Truncate   =   8, |
> > |                   | Append     =  16, |  Append     =  16, |
> > |                   | Read       =  32, |  Read       =  32, |
> > |                   | Write      =  64, |  Write      =  64, |
> > |                   | ReadWrite  = 128  |  ReadWrite  = 128  |
> > +-------------------+-------------------+--------------------+
> >
> >Note that Truncate, Append, Read, Write and ReadWrite have
> >different semantics for the latter two.
> >
> >Does that make sense to you?
> >
> >Cheers, Andre.
> >
> >



-- 
"So much time, so little to do..."  -- Garfield