Implement Object.seal and Object.isSealed function

JerryScript-DCO-1.0-Signed-off-by: Kristof Kosztyo kkosztyo.u-szeged@partner.samsung.com

jerry-core/ecma/builtin-objects/ecma-builtin-object.cpp

@@ -178,10 +178,75 @@ ecma_builtin_object_object_get_own_property_names (ecma_value_t this_arg __attr_
  *         Returned value must be freed with ecma_free_completion_value.
  */
 static ecma_completion_value_t
-ecma_builtin_object_object_seal (ecma_value_t this_arg, /**< 'this' argument */
+ecma_builtin_object_object_seal (ecma_value_t this_arg __attr_unused___, /**< 'this' argument */
                                  ecma_value_t arg) /**< routine's argument */
 {
-  ECMA_BUILTIN_CP_UNIMPLEMENTED (this_arg, arg);
+  ecma_completion_value_t ret_value = ecma_make_empty_completion_value ();
+
+  // 1.
+  if (!ecma_is_value_object (arg))
+  {
+    ret_value = ecma_make_throw_obj_completion_value (ecma_new_standard_error (ECMA_ERROR_TYPE));
+  }
+  else
+  {
+    // 2.
+    ecma_object_t *obj_p = ecma_get_object_from_value (arg);
+
+    ecma_property_t *property_p;
+    for (property_p = ecma_get_property_list (obj_p);
+         property_p != NULL && ecma_is_completion_value_empty (ret_value);
+         property_p = ECMA_GET_POINTER (ecma_property_t, property_p->next_property_p))
+    {
+      ecma_string_t *property_name_p;
+
+      if (property_p->type == ECMA_PROPERTY_NAMEDDATA)
+      {
+        property_name_p = ECMA_GET_NON_NULL_POINTER (ecma_string_t,
+                                                     property_p->u.named_data_property.name_p);
+      }
+      else if (property_p->type == ECMA_PROPERTY_NAMEDACCESSOR)
+      {
+        property_name_p = ECMA_GET_NON_NULL_POINTER (ecma_string_t,
+                                                     property_p->u.named_accessor_property.name_p);
+      }
+      else
+      {
+        continue;
+      }
+
+      // 2.a
+      ecma_property_descriptor_t prop_desc = ecma_get_property_descriptor_from_property (property_p);
+
+      // 2.b
+      if (ecma_is_property_configurable (property_p))
+      {
+        prop_desc.is_configurable = false;
+      }
+
+      // 2.c
+      ECMA_TRY_CATCH (define_own_prop_ret,
+                      ecma_op_object_define_own_property (obj_p,
+                                                          property_name_p,
+                                                          &prop_desc,
+                                                          true),
+                      ret_value);
+      ECMA_FINALIZE (define_own_prop_ret);
+
+      ecma_free_property_descriptor (&prop_desc);
+    }
+
+    if (ecma_is_completion_value_empty (ret_value))
+    {
+      // 3.
+      ecma_set_object_extensible (obj_p, false);
+
+      // 4.
+      ret_value = ecma_make_normal_completion_value (ecma_copy_value (arg, true));
+    }
+  }
+
+  return ret_value;
 } /* ecma_builtin_object_object_seal */
 
 /**
@@ -240,10 +305,59 @@ ecma_builtin_object_object_prevent_extensions (ecma_value_t this_arg __attr_unus
  *         Returned value must be freed with ecma_free_completion_value.
  */
 static ecma_completion_value_t
-ecma_builtin_object_object_is_sealed (ecma_value_t this_arg, /**< 'this' argument */
+ecma_builtin_object_object_is_sealed (ecma_value_t this_arg __attr_unused___, /**< 'this' argument */
                                       ecma_value_t arg) /**< routine's argument */
 {
-  ECMA_BUILTIN_CP_UNIMPLEMENTED (this_arg, arg);
+  ecma_completion_value_t ret_value = ecma_make_empty_completion_value ();
+
+  // 1.
+  if (!ecma_is_value_object (arg))
+  {
+    ret_value = ecma_make_throw_obj_completion_value (ecma_new_standard_error (ECMA_ERROR_TYPE));
+  }
+  else
+  {
+    ecma_object_t *obj_p = ecma_get_object_from_value (arg);
+    ecma_property_t *property_p;
+
+    // This will be the result if the other steps doesn't change it.
+    bool sealed = false;
+
+    // 3.
+    // The pseudo code contains multiple early return but this way we get the same
+    // result.
+    if (!ecma_get_object_extensible (obj_p))
+    {
+      sealed = true;
+    }
+
+    // 2.
+    for (property_p = ecma_get_property_list (obj_p);
+         property_p != NULL && sealed;
+         property_p = ECMA_GET_POINTER (ecma_property_t, property_p->next_property_p))
+    {
+      if (property_p->type == ECMA_PROPERTY_INTERNAL)
+      {
+        continue;
+      }
+
+      JERRY_ASSERT (property_p->type == ECMA_PROPERTY_NAMEDDATA || property_p->type == ECMA_PROPERTY_NAMEDACCESSOR);
+
+      // 2.b
+      if (ecma_is_property_configurable (property_p))
+      {
+        sealed = false;
+        break;
+      }
+    }
+
+    // 4.
+    ret_value = ecma_make_simple_completion_value (sealed
+                                                   ? ECMA_SIMPLE_VALUE_TRUE
+                                                   : ECMA_SIMPLE_VALUE_FALSE);
+  }
+
+  return ret_value;
 } /* ecma_builtin_object_object_is_sealed */
 
 /**

tests/jerry/object-is-extensible.js

@@ -38,11 +38,11 @@ try
     assert (e instanceof TypeError);
 }
 
-// The functions below are unimplemented.
 // Sealed objects are by definition non-extensible.
-// var sealed = Object.seal({});
-// assert(Object.isExtensible(sealed) === false);
+var sealed = Object.seal({});
+assert (Object.isExtensible(sealed) === false);
 
+// The functions below are unimplemented.
 // Frozen objects are also by definition non-extensible.
 // var frozen = Object.freeze({});
 // assert(Object.isExtensible(frozen) === false);

tests/jerry/object_seal.js

@@ -0,0 +1,86 @@
+// Copyright 2015 Samsung Electronics Co., Ltd.
+// Copyright 2015 University of Szeged.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+var obj = {
+  prop: function() {},
+  foo: 'bar'
+};
+// New properties may be added, existing properties may be changed or removed.
+obj.foo = 'baz';
+obj.lumpy = 'woof';
+delete obj.prop;
+
+var o = Object.seal(obj);
+
+assert (o === obj);
+assert (Object.isSealed (obj) === true);
+
+// Changing property values on a sealed object still works.
+obj.foo = 'quux';
+assert (obj.foo === 'quux');
+// But you can't convert data properties to accessors, or vice versa.
+try {
+    Object.defineProperty(obj, 'foo', { get: function() { return 42; } }); // throws a TypeError
+    assert (false);
+} catch (e) {
+    assert (e instanceof TypeError);
+}
+
+// Now any changes, other than to property values, will fail.
+obj.quaxxor = 'the friendly duck'; // silently doesn't add the property
+delete obj.foo; // silently doesn't delete the property
+
+assert (obj.quaxxor === undefined);
+assert (obj.foo === 'quux')
+
+try {
+    // Attempted additions through Object.defineProperty will also throw.
+    Object.defineProperty (obj, 'ohai', { value: 17 }); // throws a TypeError
+    assert (false);
+} catch (e) {
+    assert (e instanceof TypeError);
+}
+
+try {
+    Object.defineProperties (obj, { 'ohai' : { value: 17 } });
+    assert (false);
+} catch (e) {
+    assert (e instanceof TypeError);
+}
+
+Object.defineProperty (obj, 'foo', { value: 'eit' });
+assert (obj.foo === 'eit')
+
+// Objects aren't sealed by default.
+var empty = {};
+assert (Object.isSealed (empty) === false);
+
+// If you make an empty object non-extensible, it is vacuously sealed.
+Object.preventExtensions (empty);
+assert (Object.isSealed (empty) === true);
+
+// The same is not true of a non-empty object, unless its properties are all non-configurable.
+var hasProp = { fee: 'fie foe fum' };
+Object.preventExtensions (hasProp);
+assert (Object.isSealed (hasProp) === false);
+
+// But make them all non-configurable and the object becomes sealed.
+Object.defineProperty (hasProp, 'fee', { configurable: false });
+assert (Object.isSealed (hasProp) === true);
+
+// The easiest way to seal an object, of course, is Object.seal.
+var sealed = {};
+Object.seal (sealed);
+assert (Object.isSealed (sealed) === true);