[gstreamer-bugs] [Bug 339279] Subclassing from interfaces isn't always possible

[GStreamer (bugzilla.gnome.org)]

Do not reply to this via email (we are currently unable to handle email
responses and they get discarded).  You can add comments to this bug at
http://bugzilla.gnome.org/show_bug.cgi?id=339279
 GStreamer | gst-python | Ver: HEAD CVS





------- Comment #8 from Jason Toffaletti  2006-04-27 09:58 UTC -------
I've done some thinking and the only solution I can come up with that doesn't
involve changing GstURIHandlerInterface is pretty ugly. Basically all python
URIHandlers are fake and never registered with gstreamer in the traditional
sense. Instead a global python GstURIHandler is registered only once for each
uri type (GST_URI_SINK, GST_URI_SRC) and gst-python keeps its own registery of
python URIHandlers. When Gstreamer calls get_protocols for the global
GstURIHandlerInterface, it returns a list of all protocols handled by every
python URIHandler. When set_uri is called, it associates that instance of
GstURIHandler with the real python GstElement which handles the protocol so it
is able to proxy the function calls.

# gst code
class URIHandler(object):

    type = gst.URI_UNKNOWN
    protocols = []

    def get_uri(self):
        raise UnimplementedError

    def set_uri(self, uri):
        raise UnimplementedError

def register_uri_handler(klass):
    assert issubclass(klass, URIHandler):
    _register_uri_handler(klass, klass.type)

# _register_uri_handler is the C function which maintains the global
# list of src and sink uri handlers and takes care of registering
# the two real GstURIHandler proxies with gstreamer.

# application code
class DaapSrc(gst.Element, gst.URIHandler):

    type = gst.URI_SRC
    protocols = ['daap']

    def get_uri(self):
        return 'daap'

    def set_uri(self, uri):
        pass

gst.register_uri_handler(DaapSrc)


-- 
Configure bugmail: http://bugzilla.gnome.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the assignee for the bug.