Encapsulate RCLASS_ATTACHED_OBJECT

Right now the attached object is stored as an instance variable
and all the call sites that either get or set it have to know how it's
stored.

It's preferable to hide this implementation detail behind accessors
so that it is easier to change how it's stored.

1 files changed, 13 insertions, 0 deletions

diff --git a/internal/class.h b/internal/class.h
index 02a2e38ffe..b777548174 100644
--- a/internal/class.h
+++ b/internal/class.h
@@ -8,9 +8,11 @@
  *             file COPYING are met.  Consult the file for details.
  * @brief      Internal header for Class.
  */
+#include "id.h"
 #include "id_table.h"           /* for struct rb_id_table */
 #include "internal/serial.h"    /* for rb_serial_t */
 #include "internal/static_assert.h"
+#include "internal/variable.h"  /* for rb_class_ivar_set */
 #include "ruby/internal/stdbool.h"     /* for bool */
 #include "ruby/intern.h"        /* for rb_alloc_func_t */
 #include "ruby/ruby.h"          /* for struct RBasic */
@@ -99,6 +101,7 @@ STATIC_ASSERT(sizeof_rb_classext_t, sizeof(struct RClass) + sizeof(rb_classext_t
 #define RCLASS_SUBCLASSES(c) (RCLASS_EXT(c)->subclasses)
 #define RCLASS_SUPERCLASS_DEPTH(c) (RCLASS_EXT(c)->superclass_depth)
 #define RCLASS_SUPERCLASSES(c) (RCLASS_EXT(c)->superclasses)
+#define RCLASS_ATTACHED_OBJECT(c) (rb_attr_get(c, id__attached__))
 
 #define RICLASS_IS_ORIGIN FL_USER0
 #define RCLASS_CLONED     FL_USER1
@@ -197,4 +200,14 @@ RCLASS_SET_CLASSPATH(VALUE klass, VALUE classpath, bool permanent)
     RCLASS_EXT(klass)->permanent_classpath = permanent;
 }
 
+static inline VALUE
+RCLASS_SET_ATTACHED_OBJECT(VALUE klass, VALUE attached_object)
+{
+    assert(BUILTIN_TYPE(klass) == T_CLASS);
+    assert(FL_TEST(klass, FL_SINGLETON));
+
+    rb_class_ivar_set(klass, id__attached__, attached_object);
+    return attached_object;
+}
+
 #endif /* INTERNAL_CLASS_H */