merges r20607 from trunk into ruby_1_9_1. [ruby-dev:37407]

* enumerator.c (enumerator_rewind): If the enclosed object
  responds to a "rewind" method, call it; cf. [ruby-dev:37268]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_1@20712 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 7 insertions, 0 deletions

diff --git a/enumerator.c b/enumerator.c
index 38b6791503..5dc6eee23a 100644
--- a/enumerator.c
+++ b/enumerator.c
@@ -22,6 +22,7 @@
  */
 VALUE rb_cEnumerator;
 static VALUE sym_each;
+static ID id_rewind;
 
 VALUE rb_eStopIteration;
 
@@ -532,6 +533,8 @@ enumerator_next(VALUE obj)
  *   e.rewind   => e
  *
  * Rewinds the enumeration sequence by the next method.
+ *
+ * If the enclosed object responds to a "rewind" method, it is called.
  */
 
 static VALUE
@@ -539,6 +542,9 @@ enumerator_rewind(VALUE obj)
 {
     struct enumerator *e = enumerator_ptr(obj);
 
+    if (rb_respond_to(e->obj, id_rewind))
+	rb_funcall(e->obj, id_rewind, 0);
+
     e->fib = 0;
     e->dst = Qnil;
     e->no_next = Qfalse;
@@ -798,6 +804,7 @@ Init_Enumerator(void)
     rb_define_method(rb_cYielder, "<<", yielder_yield, -2);
 
     sym_each = ID2SYM(rb_intern("each"));
+    id_rewind = rb_intern("rewind");
 
     rb_provide("enumerator.so");	/* for backward compatibility */
 }