Support ModuleHolder-based lazy init of C++ modules with C++ bridge on android

Reviewed By: AaaChiuuu

Differential Revision: D4614479

fbshipit-source-id: 109ac34b8688f0113675e4a4479d1ddcc6169ed4

ReactCommon/cxxreact/CxxNativeModule.cpp

@@ -47,18 +47,19 @@ CxxModule::Callback convertCallback(
 }
 
 CxxNativeModule::CxxNativeModule(std::weak_ptr<Instance> instance,
-                                 std::unique_ptr<CxxModule> module)
+                                 std::string name,
+                                 CxxModule::Provider provider)
   : instance_(instance)
-  , module_(std::move(module))
-  , methods_(module_->getMethods()) {
-    module_->setInstance(instance);
-  }
+  , name_(std::move(name))
+  , provider_(provider) {}
 
 std::string CxxNativeModule::getName() {
-  return module_->getName();
+  return name_;
 }
 
 std::vector<MethodDescriptor> CxxNativeModule::getMethods() {
+  lazyInit();
+
   std::vector<MethodDescriptor> descs;
   for (auto& method : methods_) {
     assert(method.func || method.syncFunc);
@@ -68,6 +69,8 @@ std::vector<MethodDescriptor> CxxNativeModule::getMethods() {
 }
 
 folly::dynamic CxxNativeModule::getConstants() {
+  lazyInit();
+
   folly::dynamic constants = folly::dynamic::object();
   for (auto& pair : module_->getConstants()) {
     constants.insert(std::move(pair.first), std::move(pair.second));
@@ -168,5 +171,15 @@ MethodCallResult CxxNativeModule::callSerializableNativeHook(
   return method.syncFunc(std::move(args));
 }
 
+void CxxNativeModule::lazyInit() {
+  if (module_) {
+    return;
+  }
+
+  module_ = provider_();
+  methods_ = module_->getMethods();
+  module_->setInstance(instance_);
+}
+
 }
 }