|  |  |  | Libbonobo Reference Manual |  | 
|---|---|---|---|---|
| Top | Description | Object Hierarchy | ||||
| BonoboPersistFileBonoboPersistFile — Interface for anything that can save / load itself from a file. | 
                    BonoboPersistFile;
int                 (*BonoboPersistFileIOFn)            (BonoboPersistFile *pf,
                                                         const CORBA_char *uri,
                                                         CORBA_Environment *ev,
                                                         void *closure);
                    BonoboPersistFileClass;
BonoboPersistFile * bonobo_persist_file_new             (BonoboPersistFileIOFn load_fn,
                                                         BonoboPersistFileIOFn save_fn,
                                                         const gchar *iid,
                                                         void *closure);
BonoboPersistFile * bonobo_persist_file_construct       (BonoboPersistFile *pf,
                                                         BonoboPersistFileIOFn load_fn,
                                                         BonoboPersistFileIOFn save_fn,
                                                         const gchar *iid,
                                                         void *closure);
The PersistFile interface is a useful interface for Bonoboizing legacy applications, however, for new / correct applications it is far preferable to implement the BonoboPersistStream interface, since this will not only result in a nice clean to your application architecture, but also allow the transparent use of local, remote, and synthetic streams.
This interface works by connecting callbacks to the methods, in a pretty deprecated fashion, it is probably better nowadays to simply sub-class the BonoboXObject and override the epv methods. Either way, after all the caveats here is an example use:
Example 25. Persist file implementation
static gint
load_from_file (BonoboPersistFile *pf,
                const CORBA_char  *filename,
		CORBA_Environment *ev,
                void              *closure)
{
	EogImageData *image_data = closure;
	g_warning ("Load from '%s'", filename);
	return 0; /* Return 0 on success */
}
static gint
save_to_file (BonoboPersistFile *pf,
              const CORBA_char  *filename,
              CORBA_Environment *ev,
              void              *closure)
{
	EogImageData *image_data = closure;
	g_warning ("Save to '%s'", filename);
	return 0; /* Return 0 on success */
}
    
Having implemented the callbacks we then have to register them
and aggregate the interface to our object:
  
Example 26. Aggregating a new PersistFile
EogImageData *
eog_image_data_construct (EogImageData *image_data)
{
	BonoboObject        *retval;
	BonoboPersistFile   *file;
	file = bonobo_persist_file_new (
		load_from_file, save_to_file, image_data);
	if (file == NULL) {
		bonobo_object_unref (BONOBO_OBJECT (image_data));
		return NULL;
	}
	bonobo_object_add_interface (BONOBO_OBJECT (image_data),
				     BONOBO_OBJECT (file));
	return image_data;
}
    
Note again, that you should be writing a BonoboPersistStream
interface, however if you have already done this you might like
to just have hooks through so that old apps can use the PersistFile
interface:
  
Example 27. Chaining to a PersistStream implementation
static gint
load_from_file (BonoboPersistFile *pf,
                const CORBA_char  *filename,
		CORBA_Environment *ev,
                void              *closure)
{
	Bonobo_PersistStream ps = closure;
	BonoboStream *stream;
	stream = bonobo_stream_open (
		BONOBO_IO_DRIVER_FS,
		filename, Bonobo_STORAGE_READ,
		0);
	if (!stream)
		return 0;
	.. extract content type from file ...
	Bonobo_PersistStream_load (ps, type, ev);
	return 0; /* Return 0 on success */
}
static gint
save_to_file (BonoboPersistFile *pf,
              const CORBA_char  *filename,
              CORBA_Environment *ev,
              void              *closure)
{
	Bonobo_PersistStream ps = closure;
	BonoboStream *stream;
	stream = bonobo_stream_open (
		BONOBO_IO_DRIVER_FS,
		filename, Bonobo_STORAGE_WRITE | Bonobo_STORAGE_CREATE,
		S_IRUSR | S_IWUSR | S_IRGRP);
	if (!stream)
		return 0;
	.. work out content type we want to save ...
	Bonobo_PersistStream_save (ps, type, ev);
	return 0; /* Return 0 on success */
}
     
  The mime type data can be extracted from gnome-vfs or gnome-mime.
typedef struct _BonoboPersistFile BonoboPersistFile;
BonoboPersistFile is deprecated and should not be used in newly-written code.
int (*BonoboPersistFileIOFn) (BonoboPersistFile *pf, const CORBA_char *uri, CORBA_Environment *ev, void *closure);
BonoboPersistFileIOFn is deprecated and should not be used in newly-written code.
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typedef struct {
	BonoboPersistClass parent_class;
	POA_Bonobo_PersistFile__epv epv;
	/* methods */
	int   (*load)             (BonoboPersistFile *ps,
				   const CORBA_char  *uri,
				   CORBA_Environment *ev);
	int   (*save)             (BonoboPersistFile *ps,
				   const CORBA_char  *uri,
				   CORBA_Environment *ev);
	char *(*get_current_file) (BonoboPersistFile *ps,
				   CORBA_Environment *ev);
} BonoboPersistFileClass;
BonoboPersistFileClass is deprecated and should not be used in newly-written code.
BonoboPersistFile * bonobo_persist_file_new (BonoboPersistFileIOFn load_fn, BonoboPersistFileIOFn save_fn, const gchar *iid, void *closure);
bonobo_persist_file_new is deprecated and should not be used in newly-written code.
Creates a BonoboPersistFile object.  The load_fn and save_fn
parameters might be NULL.  If this is the case, the load and save 
operations are performed by the class load and save methods
| 
 | Loading routine | 
| 
 | Saving routine | 
| 
 | OAF IID of the object this interface is aggregated to | 
| 
 | Data passed to IO routines. | 
| Returns : | the BonoboPersistFile. | 
BonoboPersistFile * bonobo_persist_file_construct (BonoboPersistFile *pf, BonoboPersistFileIOFn load_fn, BonoboPersistFileIOFn save_fn, const gchar *iid, void *closure);
bonobo_persist_file_construct is deprecated and should not be used in newly-written code.
Initializes the BonoboPersistFile object.  The load_fn and save_fn
parameters might be NULL.  If this is the case, the load and save 
operations are performed by the class load and save methods
| 
 | A BonoboPersistFile | 
| 
 | Loading routine | 
| 
 | Saving routine | 
| 
 | OAF IID of the object this interface is aggregated to | 
| 
 | Data passed to IO routines. | 
| Returns : | the BonoboPersistFile. |