Add GetPropertyAttribute method for Object in the API

Patch by Peter Varga.

BUG=none
TEST=cctest/test-api/PropertyAttributes

Review URL: http://codereview.chromium.org/7321006

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8679 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

include/v8.h

@@ -1458,6 +1458,13 @@ class Object : public Value {
 
   V8EXPORT Local<Value> Get(uint32_t index);
 
+  /**
+   * Gets the property attributes of a property which can be None or
+   * any combination of ReadOnly, DontEnum and DontDelete. Returns
+   * None when the property doesn't exist.
+   */
+  V8EXPORT PropertyAttribute GetPropertyAttributes(Handle<Value> key);
+
   // TODO(1245389): Replace the type-specific versions of these
   // functions with generic ones that accept a Handle<Value> key.
   V8EXPORT bool Has(Handle<String> key);

src/api.cc

@@ -2794,6 +2794,26 @@ Local<Value> v8::Object::Get(uint32_t index) {
 }
 
 
+PropertyAttribute v8::Object::GetPropertyAttributes(v8::Handle<Value> key) {
+  i::Isolate* isolate = Utils::OpenHandle(this)->GetIsolate();
+  ON_BAILOUT(isolate, "v8::Object::GetPropertyAttribute()",
+             return static_cast<PropertyAttribute>(NONE));
+  ENTER_V8(isolate);
+  i::HandleScope scope(isolate);
+  i::Handle<i::JSObject> self = Utils::OpenHandle(this);
+  i::Handle<i::Object> key_obj = Utils::OpenHandle(*key);
+  if (!key_obj->IsString()) {
+    EXCEPTION_PREAMBLE(isolate);
+    key_obj = i::Execution::ToString(key_obj, &has_pending_exception);
+    EXCEPTION_BAILOUT_CHECK(isolate, static_cast<PropertyAttribute>(NONE));
+  }
+  i::Handle<i::String> key_string = i::Handle<i::String>::cast(key_obj);
+  PropertyAttributes result = self->GetPropertyAttribute(*key_string);
+  if (result == ABSENT) return static_cast<PropertyAttribute>(NONE);
+  return static_cast<PropertyAttribute>(result);
+}
+
+
 Local<Value> v8::Object::GetPrototype() {
   i::Isolate* isolate = Utils::OpenHandle(this)->GetIsolate();
   ON_BAILOUT(isolate, "v8::Object::GetPrototype()",

test/cctest/test-api.cc

@@ -2132,10 +2132,15 @@ THREADED_TEST(GetSetProperty) {
 THREADED_TEST(PropertyAttributes) {
   v8::HandleScope scope;
   LocalContext context;
+  // none
+  Local<String> prop = v8_str("none");
+  context->Global()->Set(prop, v8_num(7));
+  CHECK_EQ(v8::None, context->Global()->GetPropertyAttributes(prop));
   // read-only
-  Local<String> prop = v8_str("read_only");
+  prop = v8_str("read_only");
   context->Global()->Set(prop, v8_num(7), v8::ReadOnly);
   CHECK_EQ(7, context->Global()->Get(prop)->Int32Value());
+  CHECK_EQ(v8::ReadOnly, context->Global()->GetPropertyAttributes(prop));
   Script::Compile(v8_str("read_only = 9"))->Run();
   CHECK_EQ(7, context->Global()->Get(prop)->Int32Value());
   context->Global()->Set(prop, v8_num(10));
@@ -2146,6 +2151,25 @@ THREADED_TEST(PropertyAttributes) {
   CHECK_EQ(13, context->Global()->Get(prop)->Int32Value());
   Script::Compile(v8_str("delete dont_delete"))->Run();
   CHECK_EQ(13, context->Global()->Get(prop)->Int32Value());
+  CHECK_EQ(v8::DontDelete, context->Global()->GetPropertyAttributes(prop));
+  // dont-enum
+  prop = v8_str("dont_enum");
+  context->Global()->Set(prop, v8_num(28), v8::DontEnum);
+  CHECK_EQ(v8::DontEnum, context->Global()->GetPropertyAttributes(prop));
+  // absent
+  prop = v8_str("absent");
+  CHECK_EQ(v8::None, context->Global()->GetPropertyAttributes(prop));
+  Local<Value> fake_prop = v8_num(1);
+  CHECK_EQ(v8::None, context->Global()->GetPropertyAttributes(fake_prop));
+  // exception
+  TryCatch try_catch;
+  Local<Value> exception =
+      CompileRun("({ toString: function() { throw 'exception';} })");
+  CHECK_EQ(v8::None, context->Global()->GetPropertyAttributes(exception));
+  CHECK(try_catch.HasCaught());
+  String::AsciiValue exception_value(try_catch.Exception());
+  CHECK_EQ("exception", *exception_value);
+  try_catch.Reset();
 }