BonoboMonikerExtender

BonoboMonikerExtender — A way to extend arbitary monikers

Synopsis

                    BonoboMonikerExtender;
                    BonoboMonikerExtenderClass;
Bonobo_Unknown      (*BonoboMonikerExtenderFn)          (BonoboMonikerExtender *extender,
                                                         const Bonobo_Moniker parent,
                                                         const Bonobo_ResolveOptions *options,
                                                         const CORBA_char *display_name,
                                                         const CORBA_char *requested_interface,
                                                         CORBA_Environment *ev);
BonoboMonikerExtender * bonobo_moniker_extender_new     (BonoboMonikerExtenderFn resolve,
                                                         gpointer data);
Bonobo_MonikerExtender  bonobo_moniker_find_extender    (const gchar *name,
                                                         const gchar *interface,
                                                         CORBA_Environment *opt_ev);
Bonobo_Unknown      bonobo_moniker_use_extender         (const gchar *extender_oafiid,
                                                         BonoboMoniker *moniker,
                                                         const Bonobo_ResolveOptions *options,
                                                         const CORBA_char *requested_interface,
                                                         CORBA_Environment *opt_ev);

Object Hierarchy

  GObject
   +----BonoboObject
         +----BonoboMonikerExtender

Description

A moniker extender is used to extend the functionality of a moniker. There are two standard moniker extenders that cannot be system wide, since they use the oaf database to expand the scope of a moniker to arbitrarily many interfaces. These are invoked explicitely by monikers implementing the stream interface in the following way:

Example 18. Explicit Stream extender usage example

Bonobo_Unknown
example_moniker_resolve (BonoboMoniker               *moniker,
             const Bonobo_ResolveOptions *options,
             const CORBA_char            *requested_interface,
             CORBA_Environment           *ev)
{
    if (!strcmp (requested_interface, "IDL:Bonobo/Stream:1.0"))
        return handle_stream (moniker, options, ev);
    else
        return bonobo_moniker_use_extender (
            "OAFIID:Bonobo_MonikerExtender_stream",
            moniker, options, requested_interface, ev);
}

The moniker extender essentialy resolves 'moniker' against stream and by some means ( not known when the moniker was written ) converts this to a new exotic interface - via. the PersistStream interface.

All standard moniker extenders are registered by adding a fragment like this:

Example 19. Oaf information for an extender

1
2
3

<oaf_attribute name="bonobo:moniker_extender" type="stringv">
    <item value="file:"/>
</oaf_attribute>

to the .oaf file. This registers the extender with the system, such that when a moniker resolve fails an extender can be found for any of the monikers with prefix specified in the "bonobo:moniker_extender" stringv.

Implementing your own extender is extremely simple, much like BonoboMonikerSimple.

Example 20. Oaf information for an extender

Bonobo_Unknown
example_extender_resolve (BonoboMonikerExtender *extender,
              const Bonobo_Moniker   m,
              const Bonobo_ResolveOptions *options,
              const CORBA_char      *display_name,
              const CORBA_char      *requested_interface,
              CORBA_Environment     *ev)
{
    ... resolve 'm' against an interface we know it supports ...
    ... then use that interface to provide requested_interface ...
}

It is registered again in much the same way in your factory:

Example 21. Creating a new simple moniker

static BonoboObject *
bonobo_std_moniker_factory (BonoboGenericFactory *this,
                const char           *object_id,
                void                 *data)
{
    g_return_val_if_fail (object_id != NULL, NULL);
    if (!strcmp (object_id, "OAFIID:Bonobo_MonikerExtender_file"))
        return BONOBO_OBJECT (bonobo_moniker_extender_new (
            example_extender_resolve, NULL));
    else
        return NULL;
}

Details

BonoboMonikerExtender

typedef struct _BonoboMonikerExtender BonoboMonikerExtender;

Implements a moniker extender: Bonobo::MonikerExtender.

BonoboMonikerExtenderClass

typedef struct {
	BonoboObjectClass      parent_class;

	POA_Bonobo_MonikerExtender__epv epv;
	
	BonoboMonikerExtenderFn resolve;
} BonoboMonikerExtenderClass;

BonoboMonikerExtender's class.

BonoboMonikerExtenderFn ()

Bonobo_Unknown      (*BonoboMonikerExtenderFn)          (BonoboMonikerExtender *extender,
                                                         const Bonobo_Moniker parent,
                                                         const Bonobo_ResolveOptions *options,
                                                         const CORBA_char *display_name,
                                                         const CORBA_char *requested_interface,
                                                         CORBA_Environment *ev);

Moniker resolution callback function.

`extender` :	extender (self)
`parent` :	parent moniker
`options` :	resolve options
`display_name` :	? FIXME
`requested_interface` :	? FIXME
`ev` :
Returns :	the resolution resulting object

bonobo_moniker_extender_new ()

BonoboMonikerExtender * bonobo_moniker_extender_new     (BonoboMonikerExtenderFn resolve,
                                                         gpointer data);

This creates a new moniker extender.

`resolve` :	the resolve function that will be used to do the extension
`data` :	user data to be passed back to the resolve function.
Returns :	the extender object

bonobo_moniker_find_extender ()

Bonobo_MonikerExtender  bonobo_moniker_find_extender    (const gchar *name,
                                                         const gchar *interface,
                                                         CORBA_Environment *opt_ev);

This routine tries to locate an extender for our moniker by examining a registry of extenders that map new interfaces to certain moniker names.

`name` :	the name of the moniker we want to extend eg. 'file:'
`interface` :	the interface we want to resolve to
`opt_ev` :	an optional corba exception environment.
Returns :	an appropriate extender or CORBA_OBJECT_NIL.

bonobo_moniker_use_extender ()

Bonobo_Unknown      bonobo_moniker_use_extender         (const gchar *extender_oafiid,
                                                         BonoboMoniker *moniker,
                                                         const Bonobo_ResolveOptions *options,
                                                         const CORBA_char *requested_interface,
                                                         CORBA_Environment *opt_ev);

Locates a known extender via. OAFIID; eg. OAFIID:Bonobo_Moniker_Extender_file

`extender_oafiid` :	The IID of the extender to use
`moniker` :	the moniker to extend
`options` :	resolve options
`requested_interface` :	the requested interface
`opt_ev` :	optional corba environment
Returns :	the resolved result or CORBA_OBJECT_NIL.

			Libbonobo Reference Manual
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