4 files changed, 19 insertions, 2 deletions
diff --git a/ChangeLog b/ChangeLog
index d91b700f79..0c4f978e2b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+Mon Jun  1 04:15:42 2015  Koichi Sasada  <ko1@atdot.net>
+
+	* class.c (rb_class_has_methods): added to reduce depenedency
+	  to internal class data structure.
+
+	* internal.h: ditto.
+
+	* hash.c (has_extra_methods): use added function.
+
 Mon Jun  1 04:11:48 2015  Koichi Sasada  <ko1@atdot.net>
 
 	* gc.c , gc.h (rb_obj_info): export obj_info(VALUE) for debugging.
diff --git a/class.c b/class.c
index 37ad4b542b..2409e0d68b 100644
--- a/class.c
+++ b/class.c
@@ -1985,6 +1985,13 @@ rb_get_kwargs(VALUE keyword_hash, const ID *table, int required, int optional, V
 #undef extract_kwarg
 }
 
+int
+rb_class_has_methods(VALUE c)
+{
+    st_table *mtbl = RCLASS_M_TBL(c);
+    return mtbl && mtbl->num_entries ? TRUE : FALSE;
+}
+
 /*!
  * \}
  */
diff --git a/hash.c b/hash.c
index bd099ce94d..60e980763c 100644
--- a/hash.c
+++ b/hash.c
@@ -37,8 +37,7 @@ has_extra_methods(VALUE klass)
     const VALUE base = rb_cHash;
     VALUE c = klass;
     while (c != base) {
-	st_table *mtbl = RCLASS_M_TBL(c);
-	if (mtbl && mtbl->num_entries) return klass;
+	if (rb_class_has_methods(c)) return klass;
 	c = RCLASS_SUPER(c);
     }
     return 0;
diff --git a/internal.h b/internal.h
index 95ce1f0daa..01485dee6c 100644
--- a/internal.h
+++ b/internal.h
@@ -667,6 +667,8 @@ VALUE rb_singleton_class_clone_and_attach(VALUE obj, VALUE attach);
 VALUE rb_singleton_class_get(VALUE obj);
 void Init_class_hierarchy(void);
 
+int rb_class_has_methods(VALUE c);
+
 /* compar.c */
 VALUE rb_invcmp(VALUE, VALUE);