Implement Proxy object [[Get]] internal method (#3604)

The algorithm is based on ECMA-262 v6, 9.5.8

JerryScript-DCO-1.0-Signed-off-by: Adam Szilagyi aszilagy@inf.u-szeged.hu

jerry-core/ecma/operations/ecma-proxy-object.c

@@ -414,8 +414,101 @@ ecma_proxy_object_get (ecma_object_t *obj_p, /**< proxy object */
                        ecma_value_t receiver) /**< receiver to invoke getter function */
 {
   JERRY_ASSERT (ECMA_OBJECT_IS_PROXY (obj_p));
-  JERRY_UNUSED_3 (obj_p, prop_name_p, receiver);
-  return ecma_raise_type_error (ECMA_ERR_MSG ("UNIMPLEMENTED: Proxy.[[Get]]"));
+
+  ecma_proxy_object_t *proxy_obj_p = (ecma_proxy_object_t *) obj_p;
+
+  /* 2. */
+  ecma_value_t handler = proxy_obj_p->handler;
+
+  /* 3. */
+  if (ecma_is_value_null (handler))
+  {
+    return ecma_raise_type_error (ECMA_ERR_MSG ("Handler can not be null."));
+  }
+
+  /* 4. */
+  JERRY_ASSERT (ecma_is_value_object (handler));
+
+  /* 5. */
+  ecma_value_t target = proxy_obj_p->target;
+
+  /* 6. */
+  ecma_value_t trap = ecma_op_get_method_by_magic_id (handler, LIT_MAGIC_STRING_GET);
+
+  /* 7. */
+  if (ECMA_IS_VALUE_ERROR (trap))
+  {
+    return trap;
+  }
+
+  ecma_object_t *target_obj_p = ecma_get_object_from_value (target);
+
+  /* 8. */
+  if (ecma_is_value_undefined (trap))
+  {
+    return ecma_op_object_get_with_receiver (target_obj_p, prop_name_p, receiver);
+  }
+
+  ecma_object_t *func_obj_p = ecma_get_object_from_value (trap);
+  ecma_value_t prop_value = ecma_make_prop_name_value (prop_name_p);
+  ecma_value_t args[] = { target, prop_value, receiver };
+
+  /* 9. */
+  ecma_value_t trap_result = ecma_op_function_call (func_obj_p, handler, args, 3);
+
+  ecma_deref_object (func_obj_p);
+
+  /* 10. */
+  if (ECMA_IS_VALUE_ERROR (trap_result))
+  {
+    return trap_result;
+  }
+
+  /* 11. */
+  ecma_property_descriptor_t target_desc;
+
+  ecma_value_t status = ecma_op_object_get_own_property_descriptor (target_obj_p, prop_name_p, &target_desc);
+
+  /* 12. */
+  if (ECMA_IS_VALUE_ERROR (status))
+  {
+    return status;
+  }
+
+  /* 13. */
+  if (ecma_is_value_true (status))
+  {
+    ecma_value_t ret_value = ECMA_VALUE_EMPTY;
+
+    if ((target_desc.flags & ECMA_PROP_IS_VALUE_DEFINED)
+        && !(target_desc.flags & ECMA_PROP_IS_CONFIGURABLE)
+        && !(target_desc.flags & ECMA_PROP_IS_WRITABLE)
+        && !ecma_op_same_value (trap_result, target_desc.value))
+    {
+      ret_value = ecma_raise_type_error (ECMA_ERR_MSG ("given property is a read-only and non-configurable"
+                                                       " data property on the proxy target"));
+    }
+    else if (!(target_desc.flags & ECMA_PROP_IS_CONFIGURABLE)
+            && (target_desc.flags & (ECMA_PROP_IS_GET_DEFINED | ECMA_PROP_IS_SET_DEFINED))
+            && target_desc.get_p == NULL
+            && !ecma_is_value_undefined (trap_result))
+    {
+      ret_value = ecma_raise_type_error (ECMA_ERR_MSG ("given property is a non-configurable property and"
+                                                       " does not have a getter function"));
+    }
+
+    ecma_free_property_descriptor (&target_desc);
+
+    if (ECMA_IS_VALUE_ERROR (ret_value))
+    {
+      ecma_free_value (trap_result);
+
+      return ret_value;
+    }
+  }
+
+  /* 14. */
+  return trap_result;
 } /* ecma_proxy_object_get */
 
 /**

tests/jerry/es2015/proxy_create.js

@@ -29,13 +29,6 @@ try {
   assert(e instanceof TypeError);
 }
 
-try {
-  proxy.a;
-  assert(false);
-} catch (e) {
-  assert(e instanceof TypeError);
-}
-
 try {
   new Proxy(undefined, undefined);
   assert(false);

tests/jerry/es2015/proxy_get.js

@@ -12,7 +12,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// TODO: Update these tests when the internal routine has been implemented
+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
 
 var target = {};
 var handler = { get (target) {
@@ -26,7 +28,7 @@ try {
   proxy.a
   assert(false);
 } catch (e) {
-  assert(e instanceof TypeError);
+  assert(e === 42);
 }
 
 try {
@@ -34,7 +36,7 @@ try {
   proxy[2];
   assert(false);
 } catch (e) {
-  assert(e instanceof TypeError);
+  assert(e === 42);
 }
 
 try {
@@ -42,5 +44,91 @@ try {
   proxy + "foo";
   assert(false);
 } catch (e) {
-  assert(e instanceof TypeError);
+  assert(e === 42);
+}
+
+// test basic funcionality
+var target = {
+  target_one: 1,
+  prop: "value"
+};
+
+var handler = {handler: 1};
+var proxy = new Proxy(target, handler);
+
+assert(proxy.prop === "value");
+assert(proxy.nothing === undefined);
+assert(proxy.handler === undefined);
+
+handler.get = function () {return "value 2"};
+
+assert(proxy.prop === "value 2");
+assert(proxy.nothing === "value 2");
+assert(proxy.handler === "value 2");
+
+var handler2 = new Proxy({get: function() {return "value 3"}}, {});
+var proxy2 = new Proxy(target, handler2);
+
+assert(proxy2.prop === "value 3");
+assert(proxy2.nothing === "value 3");
+assert(proxy2.handler === "value 3");
+
+// test when get throws an error
+var handler = new Proxy({}, {get: function() {throw 42;}});
+var proxy = new Proxy ({}, handler);
+
+try {
+  proxy.prop;
+  assert(false);
+} catch (e) {
+  assert(e === 42);
+}
+
+// test when trap is undefined
+var handler = new Proxy({}, {get: function() {return undefined}});
+var target = {prop: "value"};
+var proxy = new Proxy(target, handler);
+assert(proxy.prop === "value");
+assert(proxy.prop2 === undefined);
+
+// test when invariants gets violated
+var target = {};
+var handler = {get: function(r, p){if (p != "key4") return "value"}}
+var proxy = new Proxy(target, handler);
+
+assert(proxy.key === "value");
+assert(proxy.key2 === "value");
+assert(proxy.key3 === "value");
+assert(proxy.key4 === undefined);
+
+Object.defineProperty(target, "key", {
+  configurable: false,
+  writable: false,
+  value: "different value"
+});
+
+try {
+  proxy.key;
+  assert(false);
+} catch (e) {
+  assert(e instanceof TypeError)
+}
+
+Object.defineProperty(target, "key2", {
+  configurable: false,
+  get: function() {return "different value"}
+});
+
+assert(proxy.key2 === "value");
+
+Object.defineProperty(target, "key3", {
+  configurable: false,
+  set: function() {}
+});
+
+try {
+  proxy.key3;
+  assert(false);
+} catch (e) {
+  assert(e instanceof TypeError)
 }

tests/jerry/es2015/proxy_revocable.js

@@ -23,12 +23,7 @@ var revocable = Proxy.revocable(target, handler);
 
 var proxy = revocable.proxy;
 
-try {
-  proxy.a; // FIXME: this should return 5 when proxy.[[Get]] has been implemted
-  assert(false);
-} catch (e) {
-  assert(e instanceof TypeError);
-}
+assert(proxy.a === 5);
 
 revocable.revoke();
 

tests/jerry/es2015/proxy_set.js

@@ -29,10 +29,3 @@ try {
   assert(e instanceof TypeError);
 }
 
-try {
-  // 22.1.3.6.11.b
-  Array.prototype.fill.call(proxy, 'foo', 0, 5);
-  assert(false);
-} catch (e) {
-  assert(e instanceof TypeError);
-}