add RefString getter

to python now unpacks VipsRefString on get_value()

ChangeLog

@@ -6,6 +6,7 @@
 - vips_copy() can turn 1xN or Nx1 M-band images into MxN one-band images
 - added bandand() bandor() bandeor() convenience funcs to Python
 - oops, base64 encode could pad by up to two zero bytes
+- added VipsRefString as a thing that gi bindings can unpack
 
 7/5/15 started 8.0.3
 - dzsave and tif pyr write could fail for some image dimensions, thanks Jonas

TODO

@@ -1,3 +1,5 @@
+- does ruby need to unpack RefString as well? what about C++?
+
 - how about something like vips_grid() which turns a tall thin one-band 
   image into a much smaller many-band image?
 

libvips/include/vips/type.h

@@ -135,6 +135,12 @@ GType vips_save_string_get_type( void );
  * The #GType for a #VipsRefString.
  */
 #define VIPS_TYPE_REF_STRING (vips_ref_string_get_type())
+
+typedef struct _VipsRefString { 
+	VipsArea area;
+} VipsRefString;
+
+const char *vips_ref_string_get( VipsRefString *refstr, size_t *length );
 GType vips_ref_string_get_type( void );
 
 /**

libvips/iofuncs/type.c

@@ -502,6 +502,28 @@ transform_save_string_ref_string( const GValue *src_value, GValue *dest_value )
 		vips_value_get_save_string( src_value ) );
 }
 
+/**
+ * vips_ref_string_get:
+ * @refstr: the #VipsRefString to fetch from
+ * @length: (allow-none): return length here, optionally
+ *
+ * Get a pointer to the private string inside a refstr. Handy for language
+ * bindings. 
+ *
+ * See also: vips_value_get_ref_string().
+ *
+ * Returns: (transfer none): The C string held by @refstr. 
+ */
+const char *
+vips_ref_string_get( VipsRefString *refstr, size_t *length )
+{
+	VipsArea *area = VIPS_AREA( refstr );
+
+	g_assert( area->type == G_TYPE_DOUBLE ); 
+
+	return( vips_area_get_data( area, length, NULL, NULL, NULL ) ); 
+}
+
 GType
 vips_ref_string_get_type( void )
 {

python/Vips.py

@@ -95,6 +95,7 @@ def imageize(match_image, value):
 # bytes(). 
 
 unpack_types = [[Vips.Blob, lambda x: bytes(x.get())],
+                [Vips.RefString, lambda x: x.get()],
                 [Vips.ArrayDouble, lambda x: x.get()],
                 [Vips.ArrayImage, lambda x: x.get()], 
                 [Vips.ArrayInt, lambda x: x.get()]]