Handle rewind on primed V8Generator

tests/generators_from_v8_003.phpt

@@ -0,0 +1,41 @@
+--TEST--
+Test V8::executeString() : Generators V8 -> PHP (rewind)
+--SKIPIF--
+<?php require_once(dirname(__FILE__) . '/skipif.inc'); ?>
+--FILE--
+<?php
+
+$js = <<<EOJS
+function* TheGen() {
+  for(var i = 0; i < 4; i ++) {
+    yield i;
+  }
+}
+
+TheGen();
+EOJS;
+
+$v8 = new V8Js();
+$gen = $v8->executeString($js);
+
+foreach($gen as $a) {
+    var_dump($a);
+}
+
+foreach($gen as $a) {
+    var_dump($a);
+}
+
+?>
+===EOF===
+--EXPECTF--
+int(0)
+int(1)
+int(2)
+int(3)
+
+Fatal error: Uncaught V8JsException: V8Generator::rewind not supported by ES6 in %s
+Stack trace:
+#0 %s: V8Generator->rewind()
+#1 {main}
+  thrown in %s on line 20

v8js_v8object_class.cc

@@ -616,6 +616,14 @@ PHP_METHOD(V8Generator, next)
  */
 PHP_METHOD(V8Generator, rewind)
 {
+	v8js_v8generator *g = Z_V8JS_V8GENERATOR_OBJ_P(getThis());
+
+	if(g->primed) {
+		zend_throw_exception(php_ce_v8js_exception,
+			"V8Generator::rewind not supported by ES6", 0 TSRMLS_CC);
+
+	}
+
 	RETURN_FALSE;
 }
 /* }}} */