|  |  |  | Libbonobo Reference Manual |  | 
|---|---|---|---|---|
| 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 1. 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 2. 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 3. 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.
| pf: | |
| uri: | |
| ev: | |
| closure: | |
| Returns : | 
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
| load_fn: | Loading routine | 
| save_fn: | Saving routine | 
| iid: | OAF IID of the object this interface is aggregated to | 
| closure: | 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
| pf: | A BonoboPersistFile | 
| load_fn: | Loading routine | 
| save_fn: | Saving routine | 
| iid: | OAF IID of the object this interface is aggregated to | 
| closure: | Data passed to IO routines. | 
| Returns : | the BonoboPersistFile. |