Re: Questions about tailoring libdmapsharing API to benefit GObject introspection

[Philip Withnall <philip tecnocode co uk>]

On Sun, 2017-11-12 at 18:06 -0500, W. Michael Petullo wrote:
> > > I am the maintainer of libdmapsharing, a GObject-based library. I
> > > am
> > > just now getting around to adjusting the library's API to better
> > > suit
> > > GObject introspection. I am not sure how to process on two things
> > > having
> > > to do with object properties.
> > >
> > > One of my interfaces, the DAAPRecord, has among its properties
> > > two
> > > items: hash, a GLib2 ByteArray/g_param_spec_pointer and
> > > mediakind, a
> > > g_param_spec_enum. I am trying to implement an object of this
> > > interface in
> > > Python, but I am not sure how to proceed with either of these
> > > properties.
> > > (As I mentioned, I am willing to modify the libdmapsharing
> > > interface
> > > to
> > > facilitate this if necessary.)
> > >
> > > I am not sure how to best handle hash. Should I create a box
> > > type? It
> > > seems like the should be a straightforward approach to handle a
> > > ByteArray.
>
>  
> > Can you provide a link to the code in question, and a copy of the
> > relevant bit of the generated GIR file?
> >
> > My first guess would be that you are right, and it should be a
> > boxed
> > type. See the GTlsCertificate:certificate property for an example.
> >
> > https://git.gnome.org/browse/glib/tree/gio/gtlscertificate.c#n106
>
>  
> > > For mediakind, I get a warning if I try this:
> > >
> > >   class PyDAAPRecord((GObject.GObject, DAAP.Record, DMAP.Record):
> > >             # ...
> > >       mediakind = GObject.property(type=GObject.TYPE_INT,
> > > default=0)
> > That looks like more of a Python thing, which I can’t help with,
> > sorry.
>
> The code is available with:
>
>       git clone git://git.gnome.org/libdmapsharing
>
> Here are the relavent parts of DMAP-3.2.git/DAAP-3.2.gir:
>
>       <enumeration name="MediaKind"
>                    glib:type-name="DMAPMediaKind"
>                    glib:get-type="dmap_media_kind_get_type"
>                    c:type="DMAPMediaKind">
>               <member name="music"
>                       value="1"
>                       c:identifier="DMAP_MEDIA_KIND_MUSIC"
>                       glib:nick="music">
>               </member>
>               <member name="movie"
>                       value="2"
>                       c:identifier="DMAP_MEDIA_KIND_MOVIE"
>                       glib:nick="movie">
>               </member>
>               <member name="podcast"
>                       value="32"
>                       c:identifier="DMAP_MEDIA_KIND_PODCAST"
>                       glib:nick="podcast">
>               </member>
>               <member name="tv_show"
>                       value="64"
>                       c:identifier="DMAP_MEDIA_KIND_TV_SHOW"
>                       glib:nick="tv-show">
>               </member>
>       </enumeration>
>
>       <property name="hash" writable="1" transfer-ownership="none">
>               <type name="gpointer" c:type="gpointer"/>
>       </property>

Yeah, the reference to a gpointer in the GIR snippet for `hash` is
going to cause problems for bindings, as they have no idea how to deal
with a raw pointer.

Have you tried making it a boxed type, like in the GTlsCertificate
example I linked before?

Philip

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