Copy fbjni library from react-native

lib/fb/jni/WeakReference.cpp

@@ -0,0 +1,43 @@
+/*
+ * 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/Environment.h>
+#include <jni/WeakReference.h>
+
+namespace facebook {
+namespace jni {
+
+WeakReference::WeakReference(jobject strongRef) :
+  m_weakReference(Environment::current()->NewWeakGlobalRef(strongRef))
+{
+}
+
+WeakReference::~WeakReference() {
+  auto env = Environment::current();
+  FBASSERTMSGF(env, "Attempt to delete jni::WeakReference from non-JNI thread");
+  env->DeleteWeakGlobalRef(m_weakReference);
+}
+
+ResolvedWeakReference::ResolvedWeakReference(jobject weakRef) :
+  m_strongReference(Environment::current()->NewLocalRef(weakRef))
+{
+}
+
+ResolvedWeakReference::ResolvedWeakReference(const RefPtr<WeakReference>& weakRef) :
+  m_strongReference(Environment::current()->NewLocalRef(weakRef->weakRef()))
+{
+}
+
+ResolvedWeakReference::~ResolvedWeakReference() {
+  if (m_strongReference)
+    Environment::current()->DeleteLocalRef(m_strongReference);
+}
+
+} }
+