From 5127ac5c2a95f2505b5688fa7c2f810db725ca0f Mon Sep 17 00:00:00 2001
From: Ramanpreet Nara <ramanpreet@fb.com>
Date: Wed, 22 May 2019 13:11:53 -0700
Subject: [PATCH] Implement support for legacy CxxModules

Summary:
## Background
Legacy Cxx NativeModules are implemented as Hybrid classes. Essentially, when a Cxx NativeModule is requested, you instantiate its hybrid class, which then creates a C++ counterpart. Then, the bridge uses the C++ counterpart's `getModule()` method to obtain ownership of the Cxx NativeModule.

## Summary
This diff implements backwards-compability for Cxx NativeModules.

If a Cxx NativeModule implements the `TurboModule` interface, then when the module is requested by name, we:
1. Instantiate its Java hybrid class, createing a C++ counterpart.
3. Obtain the CxxModule from the C++ counterpart using `getModule()` and use it to create a `TurboCxxModule` instance (this forwards all JavaScript method calls to the CxxModule) inside `TurboModuleManager`.
5. Return this `TurboCxxModule` to JS.

Reviewed By: mdvacca

Differential Revision: D15252041

fbshipit-source-id: cdbb62632d7a8735f7687daf62de63df9e3ad2c5
---
 .../core/jni/jsireact/TurboModuleManager.cpp    | 17 ++++++++++++++---
 .../core/jni/jsireact/TurboModuleManager.h      |  2 ++
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/ReactAndroid/src/main/java/com/facebook/react/turbomodule/core/jni/jsireact/TurboModuleManager.cpp b/ReactAndroid/src/main/java/com/facebook/react/turbomodule/core/jni/jsireact/TurboModuleManager.cpp
index 995d274dda0..0a7854f93ab 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/turbomodule/core/jni/jsireact/TurboModuleManager.cpp
+++ b/ReactAndroid/src/main/java/com/facebook/react/turbomodule/core/jni/jsireact/TurboModuleManager.cpp
@@ -12,7 +12,7 @@
 #include <jsi/jsi.h>
 
 #include <jsireact/TurboModuleBinding.h>
-
+#include <jsireact/TurboCxxModule.h>
 #include <react/jni/JMessageQueueThread.h>
 
 #include "TurboModuleManager.h"
@@ -55,13 +55,18 @@ void TurboModuleManager::installJSIBindings() {
     return; // Runtime doesn't exist when attached to Chrome debugger.
   }
   TurboModuleBinding::install(*runtime_, std::make_shared<TurboModuleBinding>(
-      [this](const std::string &name) {
+      [this](const std::string &name) -> std::shared_ptr<TurboModule> {
         auto cxxModule = turboModuleManagerDelegate_->cthis()->getTurboModule(name, jsCallInvoker_);
         if (cxxModule) {
           return cxxModule;
         }
 
-        const auto moduleInstance = getJavaModule(name);
+        auto legacyCxxModule = getLegacyCxxJavaModule(name);
+        if (legacyCxxModule) {
+          return std::make_shared<react::TurboCxxModule>(legacyCxxModule->cthis()->getModule(), jsCallInvoker_);
+        }
+
+        auto moduleInstance = getJavaModule(name);
 
         if (moduleInstance) {
           return turboModuleManagerDelegate_->cthis()->getTurboModule(name, moduleInstance, jsCallInvoker_);
@@ -80,5 +85,11 @@ jni::global_ref<JTurboModule> TurboModuleManager::getJavaModule(std::string name
   return module;
 }
 
+jni::global_ref<CxxModuleWrapper::javaobject> TurboModuleManager::getLegacyCxxJavaModule(std::string name) {
+  static auto method = turboModuleManagerDelegate_->getClass()->getMethod<jni::alias_ref<CxxModuleWrapper::javaobject>(const std::string&)>("getLegacyCxxModule");
+  auto module = jni::make_global(method(turboModuleManagerDelegate_.get(), name));
+  return module;
+}
+
 } // namespace react
 } // namespace facebook
diff --git a/ReactAndroid/src/main/java/com/facebook/react/turbomodule/core/jni/jsireact/TurboModuleManager.h b/ReactAndroid/src/main/java/com/facebook/react/turbomodule/core/jni/jsireact/TurboModuleManager.h
index 305b3b18594..fbb29834e0c 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/turbomodule/core/jni/jsireact/TurboModuleManager.h
+++ b/ReactAndroid/src/main/java/com/facebook/react/turbomodule/core/jni/jsireact/TurboModuleManager.h
@@ -12,6 +12,7 @@
 #include <jsi/jsi.h>
 #include <jsireact/TurboModule.h>
 #include <jsireact/JavaTurboModule.h>
+#include <react/jni/CxxModuleWrapper.h>
 #include <react/jni/JMessageQueueThread.h>
 #include <jsireact/JSCallInvokerHolder.h>
 #include <jsireact/TurboModuleManagerDelegate.h>
@@ -37,6 +38,7 @@ private:
   jni::global_ref<TurboModuleManagerDelegate::javaobject> turboModuleManagerDelegate_;
 
   jni::global_ref<JTurboModule> getJavaModule(std::string name);
+  jni::global_ref<CxxModuleWrapper::javaobject> getLegacyCxxJavaModule(std::string name);
   void installJSIBindings();
   explicit TurboModuleManager(
     jni::alias_ref<TurboModuleManager::jhybridobject> jThis,