repository: Add new public gi_type_info_extract_ffi_return_value() API

Dealing with FFI and return values is very tricky; this API allows
sharing the bits to do it between gobject-introspection and gjs (and
potentially other FFI binding consumers).

**NOTE** I swapped the order of the arguments, under the premise that
out arguments should generally be last.

https://bugzilla.gnome.org/show_bug.cgi?id=668902

1 files changed, 6 insertions, 0 deletions

diff --git a/girepository/girffi.h b/girepository/girffi.h
index e976f924..56caff73 100644
--- a/girepository/girffi.h
+++ b/girepository/girffi.h
@@ -46,10 +46,16 @@ struct _GIFunctionInvoker {
   gpointer padding[3];
 };
 
+typedef GIArgument GIFFIReturnValue;
+
 ffi_type *    gi_type_tag_get_ffi_type            (GITypeTag type_tag, gboolean is_pointer);
 
 ffi_type *    g_type_info_get_ffi_type            (GITypeInfo           *info);
 
+void          gi_type_info_extract_ffi_return_value (GITypeInfo                  *return_info,
+                                                     GIFFIReturnValue            *ffi_value,
+                                                     GIArgument                  *arg);
+
 gboolean      g_function_info_prep_invoker        (GIFunctionInfo       *info,
                                                    GIFunctionInvoker    *invoker,
                                                    GError              **error);