## BonoboPersistStream

BonoboPersistStream — Interface for anything that can save / load itself from a Bonobo stream.

## Synopsis

                        BonoboPersistStream;
                        BonoboPersistStreamClass;
    void                (*BonoboPersistStreamIOFn)          (BonoboPersistStream *ps,
                                                             const Bonobo_Stream stream,
                                                             Bonobo_Persist_ContentType type,
                                                             void *closure,
                                                             CORBA_Environment *ev);
    Bonobo_Persist_ContentTypeList * (*BonoboPersistStreamTypesFn)
                                                            (BonoboPersistStream *ps,
                                                             void *closure,
                                                             CORBA_Environment *ev);
    BonoboPersistStream * bonobo_persist_stream_new         (BonoboPersistStreamIOFn load_fn,
                                                             BonoboPersistStreamIOFn save_fn,
                                                             BonoboPersistStreamTypesFn types_fn,
                                                             const gchar *iid,
                                                             void *closure);
    BonoboPersistStream * bonobo_persist_stream_construct   (BonoboPersistStream *ps,
                                                             BonoboPersistStreamIOFn load_fn,
                                                             BonoboPersistStreamIOFn save_fn,
                                                             BonoboPersistStreamTypesFn types_fn,
                                                             const gchar *iid,
                                                             void *closure);

## Object Hierarchy

      GObject
       +----BonoboObject
             +----BonoboPersist
                   +----BonoboPersistStream

## Description

The PersistStream interface is the interface to use for all new components that are able to load and save themselves to a stream. It should be associated with any BonoboEmbeddable for use by the container in creating a compound document.

This interface works by connecting callbacks to the methods, in a somewhat 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 28. Implementing the PersistStream callbacks

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    static void
    load_from_stream (BonoboPersistStream        *ps,
                      const Bonobo_Stream         stream,
                      Bonobo_Persist_ContentType  type,
                      void                       *closure,
                      CORBA_Environment          *ev)
    {
        EogImageData *image_data = closure;
        g_warning ("Load content from stream of type '%s'", type);
    }
    static gint
    save_to_stream (BonoboPersistStream        *ps,
                    const Bonobo_Stream         stream,
                    Bonobo_Persist_ContentType  type,
                    void                       *closure,
                    CORBA_Environment          *ev)
    {
        EogImageData *image_data = closure;
        g_warning ("Save content to stream with type '%s'", type);
    }
    static Bonobo_Persist_ContentTypeList *
    get_supported_types (BonoboPersistStream *ps,
                         void                *closure,
                         CORBA_Environment   *ev)
    {
        return bonobo_persist_generate_content_types (
            2, "text/plain", "text/html");
    }

Having implemented the callbacks we then have to register them and aggregate the interface to our object:

Example 29. Aggregating a new PersistStream

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    EogImageData *
    eog_image_data_construct (EogImageData *image_data)
    {
        BonoboObject        *retval;
        BonoboPersistStream *ps;
        ps = bonobo_persist_stream_new (
            load_from_stream, save_to_stream,
            get_supported_types, NULL,
            image_data);
        if (ps == NULL) {
            bonobo_object_unref (BONOBO_OBJECT (image_data));
            return NULL;
        }
        bonobo_object_add_interface (BONOBO_OBJECT (image_data),
                         BONOBO_OBJECT (ps));
        return image_data;
    }

## Details

### BonoboPersistStream

    typedef struct _BonoboPersistStream BonoboPersistStream;

### Warning

`BonoboPersistStream` is deprecated and should not be used in newly-written code.

### BonoboPersistStreamClass

    typedef struct {
    	BonoboPersistClass parent_class;

    	POA_Bonobo_PersistStream__epv epv;

    	/* methods */
    	void       (*load)         (BonoboPersistStream        *ps,
    				    Bonobo_Stream              stream,
    				    Bonobo_Persist_ContentType type,
    				    CORBA_Environment          *ev);
    	void       (*save)         (BonoboPersistStream        *ps,
    				    Bonobo_Stream              stream,
    				    Bonobo_Persist_ContentType type,
    				    CORBA_Environment          *ev);

    	Bonobo_Persist_ContentTypeList * (*get_content_types) (BonoboPersistStream *ps,
    							       CORBA_Environment   *ev);
    } BonoboPersistStreamClass;

### Warning

`BonoboPersistStreamClass` is deprecated and should not be used in newly-written code.

### BonoboPersistStreamIOFn ()

    void                (*BonoboPersistStreamIOFn)          (BonoboPersistStream *ps,
                                                             const Bonobo_Stream stream,
                                                             Bonobo_Persist_ContentType type,
                                                             void *closure,
                                                             CORBA_Environment *ev);

### Warning

`BonoboPersistStreamIOFn` is deprecated and should not be used in newly-written code.

`ps` : |
`stream` : |
`type` : |
`closure` : |
`ev` : |

### BonoboPersistStreamTypesFn ()

    Bonobo_Persist_ContentTypeList * (*BonoboPersistStreamTypesFn)
                                                            (BonoboPersistStream *ps,
                                                             void *closure,
                                                             CORBA_Environment *ev);

### Warning

`BonoboPersistStreamTypesFn` is deprecated and should not be used in newly-written code.

`ps` : |
`closure` : |
`ev` : |
Returns : |

### bonobo_persist_stream_new ()

    BonoboPersistStream * bonobo_persist_stream_new         (BonoboPersistStreamIOFn load_fn,
                                                             BonoboPersistStreamIOFn save_fn,
                                                             BonoboPersistStreamTypesFn types_fn,
                                                             const gchar *iid,
                                                             void *closure);

### Warning

`bonobo_persist_stream_new` is deprecated and should not be used in newly-written code.

Creates a new BonoboPersistStream object. The various operations for the object are performed by the provided callback functions, which are passed `closure` when they are invoked. If any callback is `NULL`, the corresponding operation is performed by the class load and save routines.

`load_fn` : | Loading routine
`save_fn` : | Saving routine
`types_fn` : | get_content_types routine
`iid` : | OAF IID of the object this interface is aggregated to
`closure` : | Data passed to IO routines.
Returns : | the newly-created BonoboPersistStream object.

### bonobo_persist_stream_construct ()

    BonoboPersistStream * bonobo_persist_stream_construct   (BonoboPersistStream *ps,
                                                             BonoboPersistStreamIOFn load_fn,
                                                             BonoboPersistStreamIOFn save_fn,
                                                             BonoboPersistStreamTypesFn types_fn,
                                                             const gchar *iid,
                                                             void *closure);

### Warning

`bonobo_persist_stream_construct` is deprecated and should not be used in newly-written code.

Initializes the BonoboPersistStream object. The load and save operations for the object are performed by the provided `load_fn` and `save_fn` callback functions, which are passed `closure` when they are invoked. If either `load_fn` or `save_fn` is `NULL`, the corresponding operation is performed by the class load and save routines.

`ps` : | A BonoboPersistStream object
`load_fn` : | Loading routine
`save_fn` : | Saving routine
`types_fn` : | returns the supported types
`iid` : | OAF IID of the object this interface is aggregated to
`closure` : | Data passed to IO routines.
Returns : | The initialized BonoboPersistStream object.