Name
BonoboPersistFile -- Interface for anything that can save / load itself from a file.
Synopsis
#define BONOBO_PERSIST_FILE_TYPE
struct BonoboPersistFilePrivate;
struct BonoboPersistFile;
int (*BonoboPersistFileIOFn) (BonoboPersistFile *pf,
const CORBA_char *uri,
CORBA_Environment *ev,
void *closure);
typedef BonoboPersistFileClass;
BonoboPersistFile* bonobo_persist_file_new (BonoboPersistFileIOFn load_fn,
BonoboPersistFileIOFn save_fn,
const gchar *iid,
void *closure);
BonoboPersistFile* bonobo_persist_file_construct
(BonoboPersistFile *ps,
BonoboPersistFileIOFn load_fn,
BonoboPersistFileIOFn save_fn,
const gchar *iid,
void *closure);
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Description
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 */
}
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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;
}
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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 */
}
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The mime type data can be extracted from gnome-vfs or gnome-mime.
Details
BONOBO_PERSIST_FILE_TYPE
#define BONOBO_PERSIST_FILE_TYPE BONOBO_TYPE_PERSIST_FILE /* deprecated, you should use BONOBO_TYPE_PERSIST_FILE */ |
struct BonoboPersistFilePrivate
struct BonoboPersistFilePrivate; |
struct BonoboPersistFile
struct BonoboPersistFile {
BonoboPersist persist;
char *uri;
/*
* For the sample routines, NULL if we use the ::save and ::load
* methods from the class
*/
BonoboPersistFileIOFn save_fn;
BonoboPersistFileIOFn load_fn;
void *closure;
BonoboPersistFilePrivate *priv;
}; |
BonoboPersistFileIOFn ()
int (*BonoboPersistFileIOFn) (BonoboPersistFile *pf,
const CORBA_char *uri,
CORBA_Environment *ev,
void *closure); |
BonoboPersistFileClass
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; |
bonobo_persist_file_new ()
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
bonobo_persist_file_construct ()
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