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

<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.