Define JSI bridging function for ShadowNode::Shared (#51675)

Summary:
Pull Request resolved: #51675

Changelog: [internal]

This defines a new bridging method to convert ShadowNode::Shared from and to JS. This has some benefits over the existing `shadowNodeFromValue` and `valueFromShadowNode` functions:
1. It's more convenient, as we can just use `ShadowNode::Shared` in classes implementing the codegen, and the runtime will do the conversion automatically.
2. It's safer, as it checks for nullability and throws JS exceptions except of having segmentation faults down the line.

Reviewed By: javache

Differential Revision: D75597542

fbshipit-source-id: 37c0c43cbde0f4de9a740d9da910f215ae50efbd

Author: rubennorte

packages/react-native/ReactAndroid/src/main/jni/CMakeLists.txt

@@ -93,6 +93,7 @@ add_react_common_subdir(react/renderer/mounting)
 add_react_common_subdir(react/renderer/scheduler)
 add_react_common_subdir(react/renderer/telemetry)
 add_react_common_subdir(react/renderer/uimanager)
+add_react_common_subdir(react/renderer/bridging)
 add_react_common_subdir(react/renderer/core)
 add_react_common_subdir(react/renderer/consistency)
 add_react_common_subdir(react/renderer/css)

packages/react-native/ReactCommon/React-Fabric.podspec

@@ -69,6 +69,12 @@ Pod::Spec.new do |s|
     ss.header_dir           = "react/renderer/attributedstring"
   end
 
+  s.subspec "bridging" do |ss|
+    ss.source_files         = "react/renderer/bridging/**/*.{m,mm,cpp,h}"
+    ss.exclude_files        = "react/renderer/bridging/tests"
+    ss.header_dir           = "react/renderer/bridging"
+  end
+
   s.subspec "core" do |ss|
     header_search_path = [
       "\"$(PODS_TARGET_SRCROOT)/ReactCommon\"",

packages/react-native/ReactCommon/react/renderer/bridging/CMakeLists.txt

@@ -0,0 +1,15 @@
+# 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.
+
+cmake_minimum_required(VERSION 3.13)
+set(CMAKE_VERBOSE_MAKEFILE on)
+
+include(${REACT_COMMON_DIR}/cmake-utils/react-native-flags.cmake)
+
+add_library(react_renderer_bridging INTERFACE)
+
+target_include_directories(react_renderer_bridging INTERFACE ${REACT_COMMON_DIR})
+target_compile_reactnative_options(react_renderer_bridging INTERFACE)
+target_compile_options(react_renderer_bridging INTERFACE -Wpedantic)

packages/react-native/ReactCommon/react/renderer/bridging/bridging.h

@@ -0,0 +1,50 @@
+/*
+ * 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 <jsi/jsi.h>
+#include <react/bridging/Base.h>
+#include <react/renderer/core/ShadowNode.h>
+
+namespace facebook::react {
+
+template <>
+struct Bridging<ShadowNode::Shared> {
+  static ShadowNode::Shared fromJs(
+      jsi::Runtime& rt,
+      const jsi::Value& jsiValue) {
+    auto object = jsiValue.asObject(rt);
+
+    // Using `jsi::NativeState` instead of `ShadowNodeWrapper` to avoid  doing a
+    // dynamic pointer cast twice (as we're calling `hasNativeState` and then
+    // `getNativeState`). When we use `NativeState`, JSI doesn't need to do any
+    // dynamic casts and we can do a single one on our own after the checks.
+    if (!object.hasNativeState<jsi::NativeState>(rt)) {
+      throw jsi::JSINativeException("Value is not a ShadowNode reference");
+    }
+
+    auto nativeState = object.getNativeState<jsi::NativeState>(rt);
+    auto shadowNodeWrapper =
+        std::dynamic_pointer_cast<ShadowNodeWrapper>(nativeState);
+    if (shadowNodeWrapper == nullptr ||
+        shadowNodeWrapper->shadowNode == nullptr) {
+      throw jsi::JSINativeException(
+          "Value state is nullptr, expected a ShadowNode reference");
+    }
+
+    return shadowNodeWrapper->shadowNode;
+  }
+
+  static jsi::Value toJs(jsi::Runtime& rt, const ShadowNode::Shared& value) {
+    jsi::Object obj(rt);
+    obj.setNativeState(rt, std::make_shared<ShadowNodeWrapper>(value));
+    return obj;
+  }
+};
+
+} // namespace facebook::react