feat: Generate Kotlin/JNI code for this

packages/nitrogen/src/views/kotlin/KotlinHybridViewManager.ts

@@ -4,15 +4,26 @@ import {
   createViewComponentShadowNodeFiles,
   getViewComponentNames,
 } from '../CppHybridViewComponent.js'
-import { createFileMetadataString } from '../../syntax/helpers.js'
+import {
+  createFileMetadataString,
+  escapeCppName,
+} from '../../syntax/helpers.js'
 import { NitroConfig } from '../../config/NitroConfig.js'
+import { getHybridObjectName } from '../../syntax/getHybridObjectName.js'
+import { addJNINativeRegistration } from '../../syntax/kotlin/JNINativeRegistrations.js'
+import { indent } from '../../utils.js'
 
 export function createKotlinHybridViewManager(
   spec: HybridObjectSpec
 ): SourceFile[] {
   const cppFiles = createViewComponentShadowNodeFiles(spec)
-  const javaNamespace = NitroConfig.getAndroidPackage('java/kotlin', 'views')
-  const { manager } = getViewComponentNames(spec)
+  const javaSubNamespace = NitroConfig.getAndroidPackage('java/kotlin', 'views')
+  const javaNamespace = NitroConfig.getAndroidPackage('java/kotlin')
+  const cxxNamespace = NitroConfig.getCxxNamespace('c++', 'views')
+  const { JHybridTSpec } = getHybridObjectName(spec.name)
+  const { manager, stateClassName, component, propsClassName } =
+    getViewComponentNames(spec)
+  const stateUpdaterName = `${stateClassName}Updater`
   const autolinking = NitroConfig.getAutolinkedHybridObjects()
   const viewImplementation = autolinking[spec.name]?.kotlin
   if (viewImplementation == null) {
@@ -21,18 +32,18 @@ export function createKotlinHybridViewManager(
     )
   }
 
-  const mmFile = `
+  const viewManagerCode = `
 ${createFileMetadataString(`${manager}.kt`)}
 
-package ${javaNamespace}
+package ${javaSubNamespace}
 
 import android.view.View
 import com.facebook.react.fabric.StateWrapperImpl
 import com.facebook.react.uimanager.ReactStylesDiffMap
 import com.facebook.react.uimanager.SimpleViewManager
 import com.facebook.react.uimanager.StateWrapper
 import com.facebook.react.uimanager.ThemedReactContext
-import ${NitroConfig.getAndroidPackage('java/kotlin')}.*
+import ${javaNamespace}.*
 
 /**
  * Represents the React Native \`ViewManager\` for the "${spec.name}" Nitro HybridView.
@@ -59,21 +70,159 @@ class ${manager}: SimpleViewManager<View>() {
   override fun updateState(view: View, props: ReactStylesDiffMap, stateWrapper: StateWrapper): Any? {
     val stateWrapperImpl = stateWrapper as? StateWrapperImpl ?: throw Error("StateWrapper uses a different implementation!")
     val hybridView = views[view] ?: throw Error("Couldn't find view $view in local views table!")
-    // TODO: Get props from stateWrapperImpl and update them in HybridView
+
+    ${stateUpdaterName}.updateViewProps(hybridView, stateWrapperImpl)
 
     return super.updateState(view, props, stateWrapper)
   }
 }
-  `
+  `.trim()
+
+  const updaterKotlinCode = `
+${createFileMetadataString(`${stateUpdaterName}.kt`)}
+
+package ${javaSubNamespace}
+
+import com.facebook.react.fabric.StateWrapperImpl
+import ${javaNamespace}.*
+
+class ${stateUpdaterName} {
+  companion object {
+    /**
+     * Updates the props for [view] through C++.
+     * The [state] prop is expected to contain [view]'s props as wrapped Fabric state.
+     */
+    @Suppress("KotlinJniMissingFunction")
+    @JvmStatic
+    external fun updateViewProps(view: ${viewImplementation}, state: StateWrapperImpl)
+  }
+}
+  `.trim()
+
+  const updaterJniDescriptor = NitroConfig.getAndroidPackage(
+    'java/kotlin',
+    'views',
+    stateUpdaterName
+  )
+  const updaterJniHeaderCode = `
+${createFileMetadataString(`J${stateUpdaterName}.hpp`)}
+
+#pragma once
+
+#if REACT_NATIVE_VERSION >= 78
+
+#include <fbjni/fbjni.h>
+#include <react/fabric/StateWrapperImpl.h>
+#include "${JHybridTSpec}.hpp"
+
+namespace ${cxxNamespace} {
+
+using namespace facebook;
+
+class J${stateUpdaterName}: jni::HybridClass<J${stateUpdaterName}> {
+public:
+  static constexpr auto kJavaDescriptor = "L${updaterJniDescriptor};";
+
+public:
+  static void updateViewProps(jni::alias_ref<jni::JClass>,
+                              jni::alias_ref<${JHybridTSpec}::javaobject> view,
+                              jni::alias_ref<react::StateWrapperImpl::javaobject> stateWrapper);
+
+public:
+  static void registerNatives() {
+    registerHybrid({
+      makeNativeMethod("updateViewProps", J${stateUpdaterName}::updateViewProps),
+    });
+  }
+};
+
+} // namespace ${cxxNamespace}
+
+#endif
+  `.trim()
+
+  const propsUpdaterCalls = spec.properties.map((p) => {
+    const name = escapeCppName(p.name)
+    return `
+if (props.${name}.isDirty) {
+  view->${p.cppSetterName}(props.${name}.value);
+}
+    `.trim()
+  })
+  const updaterJniCppCode = `
+${createFileMetadataString(`J${stateUpdaterName}.cpp`)}
+
+#if REACT_NATIVE_VERSION >= 78
+
+#include "J${stateUpdaterName}.hpp"
+#include "views/${component}.hpp"
+
+namespace ${cxxNamespace} {
+
+using namespace facebook;
+using ConcreteStateData = react::ConcreteState<${stateClassName}>;
+
+void J${stateUpdaterName}::updateViewProps(jni::alias_ref<jni::JClass>,
+                                           jni::alias_ref<${JHybridTSpec}::javaobject> javaView,
+                                           jni::alias_ref<react::StateWrapperImpl::javaobject> stateWrapper) {
+  ${JHybridTSpec}* view = javaView->cthis();
+  const react::State& state = stateWrapper->cthis();
+  // TODO: Can this be a static_cast?
+  const auto& concreteState = dynamic_cast<const ConcreteStateData&>(state);
+  const ${stateClassName}& data = concreteState.getData();
+  const std::optional<${propsClassName}>& maybeProps = data.getProps();
+  if (!maybeProps.has_value()) {
+    // Props aren't set yet!
+    throw std::runtime_error("${stateClassName}'s data doesn't contain any props!");
+  }
+  const ${propsClassName}& props = maybeProps.value();
+  ${indent(propsUpdaterCalls.join('\n'), '  ')}
+}
+
+} // namespace ${cxxNamespace}
+
+#endif
+`.trim()
+
+  addJNINativeRegistration({
+    namespace: cxxNamespace,
+    className: `J${stateUpdaterName}`,
+    import: {
+      name: `J${stateUpdaterName}.hpp`,
+      space: 'user',
+      language: 'c++',
+    },
+  })
 
   return [
     ...cppFiles,
     {
-      content: mmFile,
+      content: viewManagerCode,
       language: 'kotlin',
       name: `${manager}.kt`,
       platform: 'android',
-      subdirectory: [...javaNamespace.split('.')],
+      subdirectory: [...javaSubNamespace.split('.')],
+    },
+    {
+      content: updaterKotlinCode,
+      language: 'kotlin',
+      name: `${stateUpdaterName}.kt`,
+      platform: 'android',
+      subdirectory: [...javaSubNamespace.split('.')],
+    },
+    {
+      content: updaterJniHeaderCode,
+      language: 'c++',
+      name: `J${stateUpdaterName}.hpp`,
+      platform: 'android',
+      subdirectory: ['views'],
+    },
+    {
+      content: updaterJniCppCode,
+      language: 'c++',
+      name: `J${stateUpdaterName}.cpp`,
+      platform: 'android',
+      subdirectory: ['views'],
     },
   ]
 }

packages/react-native-nitro-image/nitrogen/generated/android/NitroImage+autolinking.cmake

@@ -42,6 +42,7 @@ target_sources(
   ../nitrogen/generated/android/c++/JHybridBaseSpec.cpp
   ../nitrogen/generated/android/c++/JHybridChildSpec.cpp
   ../nitrogen/generated/android/c++/JHybridTestViewSpec.cpp
+  ../nitrogen/generated/android/c++/views/JHybridTestViewStateUpdater.cpp
 )
 
 # Define a flag to check if we are building properly

packages/react-native-nitro-image/nitrogen/generated/android/NitroImageOnLoad.cpp

@@ -30,6 +30,7 @@
 #include "JHybridBaseSpec.hpp"
 #include "JHybridChildSpec.hpp"
 #include "JHybridTestViewSpec.hpp"
+#include "JHybridTestViewStateUpdater.hpp"
 #include <NitroModules/JNISharedPtr.hpp>
 #include <NitroModules/DefaultConstructableObject.hpp>
 #include "HybridTestObjectCpp.hpp"
@@ -58,6 +59,7 @@ int initialize(JavaVM* vm) {
     margelo::nitro::image::JHybridBaseSpec::registerNatives();
     margelo::nitro::image::JHybridChildSpec::registerNatives();
     margelo::nitro::image::JHybridTestViewSpec::registerNatives();
+    margelo::nitro::image::views::JHybridTestViewStateUpdater::registerNatives();
 
     // Register Nitro Hybrid Objects
     HybridObjectRegistry::registerHybridObjectConstructor(

packages/react-native-nitro-image/nitrogen/generated/android/c++/views/JHybridTestViewStateUpdater.cpp

@@ -0,0 +1,42 @@
+///
+/// JHybridTestViewStateUpdater.cpp
+/// This file was generated by nitrogen. DO NOT MODIFY THIS FILE.
+/// https://github.com/mrousavy/nitro
+/// Copyright © 2025 Marc Rousavy @ Margelo
+///
+
+#if REACT_NATIVE_VERSION >= 78
+
+#include "JHybridTestViewStateUpdater.hpp"
+#include "views/HybridTestViewComponent.hpp"
+
+namespace margelo::nitro::image::views {
+
+using namespace facebook;
+using ConcreteStateData = react::ConcreteState<HybridTestViewState>;
+
+void JHybridTestViewStateUpdater::updateViewProps(jni::alias_ref<jni::JClass>,
+                                           jni::alias_ref<JHybridTestViewSpec::javaobject> javaView,
+                                           jni::alias_ref<react::StateWrapperImpl::javaobject> stateWrapper) {
+  JHybridTestViewSpec* view = javaView->cthis();
+  const react::State& state = stateWrapper->cthis();
+  // TODO: Can this be a static_cast?
+  const auto& concreteState = dynamic_cast<const ConcreteStateData&>(state);
+  const HybridTestViewState& data = concreteState.getData();
+  const std::optional<HybridTestViewProps>& maybeProps = data.getProps();
+  if (!maybeProps.has_value()) {
+    // Props aren't set yet!
+    throw std::runtime_error("HybridTestViewState's data doesn't contain any props!");
+  }
+  const HybridTestViewProps& props = maybeProps.value();
+  if (props.someProp.isDirty) {
+    view->setSomeProp(props.someProp.value);
+  }
+  if (props.someCallback.isDirty) {
+    view->setSomeCallback(props.someCallback.value);
+  }
+}
+
+} // namespace margelo::nitro::image::views
+
+#endif

packages/react-native-nitro-image/nitrogen/generated/android/c++/views/JHybridTestViewStateUpdater.hpp

@@ -0,0 +1,39 @@
+///
+/// JHybridTestViewStateUpdater.hpp
+/// This file was generated by nitrogen. DO NOT MODIFY THIS FILE.
+/// https://github.com/mrousavy/nitro
+/// Copyright © 2025 Marc Rousavy @ Margelo
+///
+
+#pragma once
+
+#if REACT_NATIVE_VERSION >= 78
+
+#include <fbjni/fbjni.h>
+#include <react/fabric/StateWrapperImpl.h>
+#include "JHybridTestViewSpec.hpp"
+
+namespace margelo::nitro::image::views {
+
+using namespace facebook;
+
+class JHybridTestViewStateUpdater: jni::HybridClass<JHybridTestViewStateUpdater> {
+public:
+  static constexpr auto kJavaDescriptor = "Lcom.margelo.nitro.image.views.HybridTestViewStateUpdater;";
+
+public:
+  static void updateViewProps(jni::alias_ref<jni::JClass>,
+                              jni::alias_ref<JHybridTestViewSpec::javaobject> view,
+                              jni::alias_ref<react::StateWrapperImpl::javaobject> stateWrapper);
+
+public:
+  static void registerNatives() {
+    registerHybrid({
+      makeNativeMethod("updateViewProps", JHybridTestViewStateUpdater::updateViewProps),
+    });
+  }
+};
+
+} // namespace margelo::nitro::image::views
+
+#endif

packages/react-native-nitro-image/nitrogen/generated/android/kotlin/com/margelo/nitro/image/views/HybridTestViewManager.kt

@@ -40,7 +40,8 @@ class HybridTestViewManager: SimpleViewManager<View>() {
   override fun updateState(view: View, props: ReactStylesDiffMap, stateWrapper: StateWrapper): Any? {
     val stateWrapperImpl = stateWrapper as? StateWrapperImpl ?: throw Error("StateWrapper uses a different implementation!")
     val hybridView = views[view] ?: throw Error("Couldn't find view $view in local views table!")
-    // TODO: Get props from stateWrapperImpl and update them in HybridView
+
+    HybridTestViewStateUpdater.updateViewProps(hybridView, stateWrapperImpl)
 
     return super.updateState(view, props, stateWrapper)
   }

packages/react-native-nitro-image/nitrogen/generated/android/kotlin/com/margelo/nitro/image/views/HybridTestViewStateUpdater.kt

@@ -0,0 +1,23 @@
+///
+/// HybridTestViewStateUpdater.kt
+/// This file was generated by nitrogen. DO NOT MODIFY THIS FILE.
+/// https://github.com/mrousavy/nitro
+/// Copyright © 2025 Marc Rousavy @ Margelo
+///
+
+package com.margelo.nitro.image.views
+
+import com.facebook.react.fabric.StateWrapperImpl
+import com.margelo.nitro.image.*
+
+class HybridTestViewStateUpdater {
+  companion object {
+    /**
+     * Updates the props for [view] through C++.
+     * The [state] prop is expected to contain [view]'s props as wrapped Fabric state.
+     */
+    @Suppress("KotlinJniMissingFunction")
+    @JvmStatic
+    external fun updateViewProps(view: HybridTestView, state: StateWrapperImpl)
+  }
+}

packages/react-native-nitro-modules/android/CMakeLists.txt

@@ -38,6 +38,7 @@ include_directories(
   ../cpp/threading
   ../cpp/turbomodule
   ../cpp/utils
+  ../cpp/views
   # Android-specific C++ includes
   src/main/cpp/core
   src/main/cpp/registry

packages/react-native-nitro-modules/cpp/views/CachedProp.hpp

@@ -18,7 +18,7 @@ struct CachedProp {
 public:
   T value;
   OwningReference<jsi::Value> jsiValue;
-  bool isDirty;
+  bool isDirty = false;
 
 public:
   bool equals(jsi::Runtime& runtime, const jsi::Value& other) const {