object new from string() is now a vfunc

and the inverse too ... interpolate and format need fixing still

TODO

@@ -1,7 +1,13 @@
-- where exactly is vips_object_new_from_string() used? check use cases
+- interpolate needs stuff for new new_from_string etc. system
+
+  also VipsFormat ... could this replace vips_image_new_from_string()? or
+  could we call this from vips_image_new_from_string()? 
+
+  vipsobject should have a fall-back implementation that does something, I
+  don't quite know what
+
+
 
-  also revise the inverse operation: vips_object_to_string() ... should be a
-  vfunc as well since it has to match from_string() in behaviour
 
 
 

libvips/deprecated/dispatch_types.c

@@ -886,9 +886,11 @@ im_type_desc im__output_gvalue = {
 static int
 input_interpolate_init( im_object *obj, char *str )
 {
+	VipsObjectClass *interpolate_class;
 	VipsObject *object;
 
-	if( !(object = vips_object_new_from_string( "VipsInterpolate", str )) )
+	interpolate_class = vips_class_find( "VipsInterpolate", "interpolate" );
+	if( !(object = vips_object_new_from_string( interpolate_class, str )) )
 		return( -1 );
 	*obj = object;
 

libvips/include/vips/object.h

@@ -261,22 +261,28 @@ struct _VipsObjectClass {
 	 */
 	void (*postclose)( VipsObject * );
 
-	/* The CLI interface. Implement these three to get CLI input and output
+	/* The CLI interface. Implement these four to get CLI input and output
 	 * for your object.
 	 */
 
 	/* Given a command-line arg (eg. a filename), make an instance of the
-	 * object.
+	 * object. Don't call this directly, see
+	 * vips_object_new_from_string().
 	 */
 	VipsObject *(*new_from_string)( const char *string );
 
+	/* The inverse of ^^. Given an object, output what ->new_from_string()
+	 * would have been given to make that object. 
+	 */
+	void (*to_string)( VipsObject *, VipsBuf * ); 
+
 	/* Does this output arg need an arg from the command line? Image
 	 * output, for example, needs a filename to write to.
 	 */
 	gboolean output_needs_arg;
 
 	/* Write the object to the string. Return 0 for success, or -1 on
-	 * error setting vips_error(). string is NULL if output_needs_arg()
+	 * error, setting vips_error(). string is NULL if output_needs_arg()
 	 * was FALSE.
 	 */
 	int (*output_to_arg)( VipsObject *object, const char *string );
@@ -327,7 +333,8 @@ typedef void *(*VipsObjectSetArguments)( VipsObject *, void *, void * );
 VipsObject *vips_object_new( GType type, 
 	VipsObjectSetArguments set, void *a, void *b );
 
-VipsObject *vips_object_new_from_string( const char *base, const char *str );
+VipsObject *vips_object_new_from_string( VipsObjectClass *object_class, 
+	const char *p );
 void vips_object_to_string( VipsObject *object, VipsBuf *buf );
 
 void *vips_object_map( VipsSListMap2Fn fn, void *a, void *b );

libvips/iofuncs/image.c

@@ -388,14 +388,20 @@ vips_image_dispose( GObject *gobject )
 	G_OBJECT_CLASS( vips_image_parent_class )->dispose( gobject );
 }
 
-
-
 static VipsObject *
 vips_image_new_from_file_object( const char *string )
 {
 	return( VIPS_OBJECT( vips_image_new_from_file( string ) ) );
 }
 
+static void
+vips_image_to_string( VipsObject *object, VipsBuf *buf )
+{
+	VipsImage *image = VIPS_IMAGE( object );
+
+	vips_buf_appends( buf, image->filename );
+}
+
 static int 
 vips_image_write_object( VipsObject *object, const char *string )
 {
@@ -1062,6 +1068,7 @@ vips_image_class_init( VipsImageClass *class )
 	gobject_class->get_property = vips_object_get_property;
 
 	vobject_class->new_from_string = vips_image_new_from_file_object;
+	vobject_class->to_string = vips_image_to_string;;
 	vobject_class->output_needs_arg = TRUE;
 	vobject_class->output_to_arg = vips_image_write_object;
 

libvips/iofuncs/object.c

@@ -1048,11 +1048,10 @@ vips_object_set_argument_from_string( VipsObject *object,
 	g_assert( argument_class->flags & VIPS_ARGUMENT_INPUT );
 
 	if( g_type_is_a( otype, VIPS_TYPE_OBJECT ) &&
-		(oclass = g_type_class_ref( otype )) &&
+		(oclass = g_type_class_ref( otype )) ) { 
-		oclass->new_from_string ) {
 		VipsObject *object;
 
-		if( !(object = oclass->new_from_string( value )) )
+		if( !(object = vips_object_new_from_string( oclass, value )) )
 			return( -1 );
 
 		g_value_init( &gvalue, G_TYPE_OBJECT );
@@ -1232,6 +1231,26 @@ vips_object_set_required( VipsObject *object, const char *value )
 	return( 0 );
 }
 
+VipsObject *
+vips_object_new( GType type, VipsObjectSetArguments set, void *a, void *b )
+{
+	VipsObject *object;
+
+	object = VIPS_OBJECT( g_object_new( type, NULL ) );
+
+	if( set && set( object, a, b ) ) {
+		g_object_unref( object );
+		return( NULL );
+	}
+
+	if( vips_object_build( object ) ) {
+		g_object_unref( object );
+		return( NULL );
+	}
+
+	return( object );
+}
+
 /* Set object args from a string. We've seen the '(', we need to check for the
  * closing ')' and make sure there's no extra stuff.
  */
@@ -1287,16 +1306,31 @@ vips_object_set_args( VipsObject *object, const char *p )
 }
 
 VipsObject *
-vips_object_new( GType type, VipsObjectSetArguments set, void *a, void *b )
+vips_object_new_from_string( VipsObjectClass *object_class, const char *p )
 {
+	char str[PATH_MAX];
 	VipsObject *object;
+	VipsToken token;
 
-	object = VIPS_OBJECT( g_object_new( type, NULL ) );
+	g_assert( object_class->new_from_string );
 
-	if( set && set( object, a, b ) ) {
+	/* The first string in p is the main construct arg, eg. a filename.
+	 */
+	if( !(p = vips__token_need( p, VIPS_TOKEN_STRING, str, PATH_MAX )) ||
+		!(object = object_class->new_from_string( str )) )
+		return( NULL );
+
+	/* More tokens there? Set any other args.
+	 */
+	if( (p = vips__token_get( p, &token, str, PATH_MAX )) ) {
+		if( token == VIPS_TOKEN_LEFT &&
+			vips_object_set_args( object, p ) ) {
+			vips_error( "VipsObject", 
+				"%s", _( "bad object arguments" ) );
 			g_object_unref( object );
 			return( NULL );
 		}
+	}
 
 	if( vips_object_build( object ) ) {
 		g_object_unref( object );
@@ -1306,39 +1340,6 @@ vips_object_new( GType type, VipsObjectSetArguments set, void *a, void *b )
 	return( object ); 
 }
 
-static void *
-vips_object_new_from_string_set( VipsObject *object, void *a, void *b )
-{
-	const char *p = (const char *) a;
-	VipsToken token;
-	char string[PATH_MAX];
-
-	if( (p = vips__token_get( p, &token, string, PATH_MAX )) ) {
-		if( token == VIPS_TOKEN_LEFT &&
-			vips_object_set_args( object, p ) ) {
-			vips_error( "VipsObject", 
-				"%s", _( "bad object arguments" ) );
-			return( object );
-		}
-	}
-
-	return( NULL );
-}
-
-VipsObject *
-vips_object_new_from_string( const char *basename, const char *p )
-{
-	char string[PATH_MAX];
-	GType type;
-
-	if( !(p = vips__token_need( p, VIPS_TOKEN_STRING, string, PATH_MAX )) ||
-		!(type = vips_type_find( basename, string )) )
-		return( NULL );
-
-	return( vips_object_new( type,
-		vips_object_new_from_string_set, (void *) p, NULL ) );
-}
-
 static void *
 vips_object_to_string_required( VipsObject *object,
 	GParamSpec *pspec,
@@ -1398,12 +1399,16 @@ vips_object_to_string_optional( VipsObject *object,
 void
 vips_object_to_string( VipsObject *object, VipsBuf *buf )
 {
+	VipsObjectClass *object_class = VIPS_OBJECT_GET_CLASS( object );
+
 	gboolean first;
 
+	g_assert( object_class->to_string );
+
 	/* Nicknames are not guaranteed to be unique, so use the full type
 	 * name.
 	 */
-	vips_buf_appends( buf, G_OBJECT_TYPE_NAME( object ) );
+	object_class->to_string( object, buf );
 	first = TRUE;
 	(void) vips_argument_map( object,
 		vips_object_to_string_required, buf, &first );