Extract module registry creation to helper

Reviewed By: mhorowitz

Differential Revision: D4721817

fbshipit-source-id: 2fa17ca5317a57d429aa75d6c1865932af27e02f

React/CxxModule/DispatchMessageQueueThread.h

@@ -0,0 +1,40 @@
+/**
+ * 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 <cxxreact/MessageQueueThread.h>
+
+namespace facebook {
+namespace react {
+
+// RCTNativeModule arranges for native methods to be invoked on a queue which
+// is not the JS thread.  C++ modules don't use RCTNativeModule, so this little
+// adapter does the work.
+
+class DispatchMessageQueueThread : public MessageQueueThread {
+public:
+  DispatchMessageQueueThread(RCTModuleData *moduleData)
+    : moduleData_(moduleData) {}
+
+  void runOnQueue(std::function<void()>&& func) override {
+    dispatch_async(moduleData_.methodQueue, [func=std::move(func)] {
+      func();
+    });
+  }
+  void runOnQueueSync(std::function<void()>&& func) override {
+    LOG(FATAL) << "Unsupported operation";
+  }
+  void quitSynchronous() override {
+    LOG(FATAL) << "Unsupported operation";
+  }
+
+private:
+  RCTModuleData *moduleData_;
+};
+
+} }