Add Hermes implementation for Object.getPrototypeOf and Object.setPro…

…totypeOf

Summary:
Adds the implementation of the JSI methods `getPrototypeOf` and
`setPrototypeOf` for Hermes runtime.

Grafted from 9ff82875b3f0e1fba452358d52a83936d81404e9 (D66729169)
- Grafted path xplat/static_h to xplat/hermes

Reviewed By: tmikov

Differential Revision: D67412931

fbshipit-source-id: a29d60fe3c7ee12ecf9326f748707d34fc548916

API/hermes/hermes.cpp

@@ -659,6 +659,10 @@ class HermesRuntimeImpl final : public HermesRuntime,
   bool isHostFunction(const jsi::Function &) const override;
   jsi::Array getPropertyNames(const jsi::Object &) override;
 
+  void setPrototypeOf(const jsi::Object &object, const jsi::Value &prototype)
+      override;
+  jsi::Value getPrototypeOf(const jsi::Object &object) override;
+
   jsi::WeakObject createWeakObject(const jsi::Object &) override;
   jsi::Value lockWeakObject(const jsi::WeakObject &) override;
 
@@ -2018,6 +2022,32 @@ void HermesRuntimeImpl::setExternalMemoryPressure(
   ns->setContext(reinterpret_cast<void *>(amt));
 }
 
+void HermesRuntimeImpl::setPrototypeOf(
+    const jsi::Object &object,
+    const jsi::Value &prototype) {
+  if (!prototype.isObject() && !prototype.isNull()) {
+    throw jsi::JSError(
+        *this, "Object prototype argument must be an Object or null");
+  }
+
+  auto cr = vm::JSObject::setParent(
+      vm::vmcast<vm::JSObject>(phv(object)),
+      runtime_,
+      vm::dyn_vmcast<vm::JSObject>(hvFromValue(prototype)),
+      vm::PropOpFlags().plusThrowOnError());
+  checkStatus(cr.getStatus());
+}
+
+jsi::Value HermesRuntimeImpl::getPrototypeOf(const jsi::Object &object) {
+  vm::CallResult<vm::PseudoHandle<vm::JSObject>> cr =
+      vm::JSObject::getPrototypeOf(handle(object), runtime_);
+  checkStatus(cr.getStatus());
+  if (!*cr) {
+    return jsi::Value::null();
+  }
+  return valueFromHermesValue(cr->getHermesValue());
+}
+
 jsi::Value HermesRuntimeImpl::getProperty(
     const jsi::Object &obj,
     const jsi::String &name) {

unittests/API/APITest.cpp

@@ -1274,6 +1274,26 @@ TEST_P(HermesRuntimeTest, GetPropNameIdDataTest) {
   buf.clear();
 }
 
+TEST_P(HermesRuntimeTest, SetPrototypeOf) {
+  Object prototypeObj(*rt);
+  prototypeObj.setProperty(*rt, "someProperty", 123);
+  Value prototype(*rt, prototypeObj);
+
+  Object child(*rt);
+  child.setPrototype(*rt, prototype);
+  EXPECT_EQ(child.getProperty(*rt, "someProperty").getNumber(), 123);
+
+  auto getPrototypeRes = child.getPrototype(*rt).asObject(*rt);
+  EXPECT_EQ(getPrototypeRes.getProperty(*rt, "someProperty").getNumber(), 123);
+
+  // Tests null value as prototype
+  child.setPrototype(*rt, Value::null());
+  EXPECT_TRUE(child.getPrototype(*rt).isNull());
+
+  // Throw when prototype is neither an Object nor null
+  EXPECT_THROW(child.setPrototype(*rt, Value(1)), JSError);
+}
+
 INSTANTIATE_TEST_CASE_P(
     Runtimes,
     HermesRuntimeTest,