From 43ba9df55f4bfc30e9ba4dda72ff53c05599f0d5 Mon Sep 17 00:00:00 2001
From: Christoph Purrer <chpurrer@meta.com>
Date: Mon, 9 Jun 2025 19:15:47 -0700
Subject: [PATCH] Add jni target to ReactCxxPlatform (#51898)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/51898

changelog: [internal]

Reviewed By: andrewdacenko

Differential Revision: D76240376

fbshipit-source-id: bbae620dde69261e6d26d088471601e7d7e9a074
---
 .../ReactCxxPlatform/react/jni/JniHelper.cpp  | 28 +++++++++++++++++++
 .../ReactCxxPlatform/react/jni/JniHelper.h    | 19 +++++++++++++
 2 files changed, 47 insertions(+)
 create mode 100644 packages/react-native/ReactCxxPlatform/react/jni/JniHelper.cpp
 create mode 100644 packages/react-native/ReactCxxPlatform/react/jni/JniHelper.h

diff --git a/packages/react-native/ReactCxxPlatform/react/jni/JniHelper.cpp b/packages/react-native/ReactCxxPlatform/react/jni/JniHelper.cpp
new file mode 100644
index 00000000000..a3689d5d094
--- /dev/null
+++ b/packages/react-native/ReactCxxPlatform/react/jni/JniHelper.cpp
@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include <fbjni/Context.h>
+#include <fbjni/fbjni.h>
+
+namespace facebook::react {
+
+jobject getApplication(JNIEnv* env) {
+  auto activityThreadClass = env->FindClass("android/app/ActivityThread");
+  auto currentApplicationMethodID = env->GetStaticMethodID(
+      activityThreadClass, "currentApplication", "()Landroid/app/Application;");
+  return env->CallStaticObjectMethod(
+      activityThreadClass, currentApplicationMethodID);
+}
+
+jni::alias_ref<jni::AContext> getContext() {
+  auto env = facebook::jni::Environment::ensureCurrentThreadIsAttached();
+  auto application = getApplication(env);
+  return facebook::jni::wrap_alias(
+      static_cast<facebook::jni::AContext::javaobject>(application));
+}
+
+} // namespace facebook::react
diff --git a/packages/react-native/ReactCxxPlatform/react/jni/JniHelper.h b/packages/react-native/ReactCxxPlatform/react/jni/JniHelper.h
new file mode 100644
index 00000000000..8db809186f3
--- /dev/null
+++ b/packages/react-native/ReactCxxPlatform/react/jni/JniHelper.h
@@ -0,0 +1,19 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#pragma once
+
+#include <fbjni/Context.h>
+#include <fbjni/fbjni.h>
+
+namespace facebook::react {
+
+jobject getApplication(JNIEnv* env);
+
+jni::alias_ref<jni::AContext> getContext();
+
+} // namespace facebook::react