Copy fbjni library from react-native

lib/fb/jni/Hybrid.cpp

@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#include "fb/fbjni.h"
+
+
+namespace facebook {
+namespace jni {
+
+namespace detail {
+
+void HybridData::setNativePointer(std::unique_ptr<BaseHybridClass> new_value) {
+  static auto pointerField = getClass()->getField<jlong>("mNativePointer");
+  auto* old_value = reinterpret_cast<BaseHybridClass*>(getFieldValue(pointerField));
+  if (new_value) {
+    // Modify should only ever be called once with a non-null
+    // new_value.  If this happens again it's a programmer error, so
+    // blow up.
+    FBASSERTMSGF(old_value == 0, "Attempt to set C++ native pointer twice");
+  } else if (old_value == 0) {
+    return;
+  }
+  // delete on a null pointer is defined to be a noop.
+  delete old_value;
+  // This releases ownership from the unique_ptr, and passes the pointer, and
+  // ownership of it, to HybridData which is managed by the java GC.  The
+  // finalizer on hybridData calls resetNative which will delete the object, if
+  // resetNative has not already been called.
+  setFieldValue(pointerField, reinterpret_cast<jlong>(new_value.release()));
+}
+
+BaseHybridClass* HybridData::getNativePointer() {
+  static auto pointerField = getClass()->getField<jlong>("mNativePointer");
+  auto* value = reinterpret_cast<BaseHybridClass*>(getFieldValue(pointerField));
+  if (!value) {
+    throwNewJavaException("java/lang/NullPointerException", "java.lang.NullPointerException");
+  }
+  return value;
+}
+
+local_ref<HybridData> HybridData::create() {
+  return newInstance();
+}
+
+}
+
+namespace {
+void resetNative(alias_ref<detail::HybridData> jthis) {
+  jthis->setNativePointer(nullptr);
+}
+}
+
+void HybridDataOnLoad() {
+  registerNatives("com/facebook/jni/HybridData", {
+      makeNativeMethod("resetNative", resetNative),
+  });
+}
+
+}}