From de165a2cfdb9967ae99237d8c9519cc2dd232855 Mon Sep 17 00:00:00 2001
From: Yogesh Choudhary Paliyal <yogeshpaliyal.foss@gmail.com>
Date: Fri, 25 Apr 2025 05:23:43 -0700
Subject: [PATCH] refactor: Rewrite JSBundleLoader from Java to Kotlin (#50911)

Summary:
Rewrite of JSBundleLoader from Java to Kotlin in scope of https://github.com/facebook/react-native/issues/50513

## Changelog:
[ANDROID] [CHANGED] - Migrated JSBundleLoader to Kotlin

<!-- Help reviewers and the release process by writing your own changelog entry.

Pick one each for the category and type tags:

[ANDROID|GENERAL|IOS|INTERNAL] [BREAKING|ADDED|CHANGED|DEPRECATED|REMOVED|FIXED|SECURITY] - Message

For more details, see:
https://reactnative.dev/contributing/changelogs-in-pull-requests

Pull Request resolved: https://github.com/facebook/react-native/pull/50911

Test Plan: Tested using RNTester app, on both old and new arch, and tested by navigating to multiple pages

Reviewed By: cortinico

Differential Revision: D73649145

Pulled By: javache

fbshipit-source-id: 7ef1fc1ea1c53a8b914ae1aada1966e64b4c3d80
---
 .../ReactAndroid/api/ReactAndroid.api         | 19 +++-
 .../facebook/react/bridge/JSBundleLoader.java | 99 -------------------
 .../facebook/react/bridge/JSBundleLoader.kt   | 99 +++++++++++++++++++
 3 files changed, 113 insertions(+), 104 deletions(-)
 delete mode 100644 packages/react-native/ReactAndroid/src/main/java/com/facebook/react/bridge/JSBundleLoader.java
 create mode 100644 packages/react-native/ReactAndroid/src/main/java/com/facebook/react/bridge/JSBundleLoader.kt

diff --git a/packages/react-native/ReactAndroid/api/ReactAndroid.api b/packages/react-native/ReactAndroid/api/ReactAndroid.api
index 6fc61e5da88..0476b31828f 100644
--- a/packages/react-native/ReactAndroid/api/ReactAndroid.api
+++ b/packages/react-native/ReactAndroid/api/ReactAndroid.api
@@ -770,15 +770,24 @@ public final class com/facebook/react/bridge/JSApplicationIllegalArgumentExcepti
 }
 
 public abstract class com/facebook/react/bridge/JSBundleLoader {
+	public static final field Companion Lcom/facebook/react/bridge/JSBundleLoader$Companion;
 	public fun <init> ()V
-	public static fun createAssetLoader (Landroid/content/Context;Ljava/lang/String;Z)Lcom/facebook/react/bridge/JSBundleLoader;
-	public static fun createCachedBundleFromNetworkLoader (Ljava/lang/String;Ljava/lang/String;)Lcom/facebook/react/bridge/JSBundleLoader;
-	public static fun createCachedSplitBundleFromNetworkLoader (Ljava/lang/String;Ljava/lang/String;)Lcom/facebook/react/bridge/JSBundleLoader;
-	public static fun createFileLoader (Ljava/lang/String;)Lcom/facebook/react/bridge/JSBundleLoader;
-	public static fun createFileLoader (Ljava/lang/String;Ljava/lang/String;Z)Lcom/facebook/react/bridge/JSBundleLoader;
+	public static final fun createAssetLoader (Landroid/content/Context;Ljava/lang/String;Z)Lcom/facebook/react/bridge/JSBundleLoader;
+	public static final fun createCachedBundleFromNetworkLoader (Ljava/lang/String;Ljava/lang/String;)Lcom/facebook/react/bridge/JSBundleLoader;
+	public static final fun createCachedSplitBundleFromNetworkLoader (Ljava/lang/String;Ljava/lang/String;)Lcom/facebook/react/bridge/JSBundleLoader;
+	public static final fun createFileLoader (Ljava/lang/String;)Lcom/facebook/react/bridge/JSBundleLoader;
+	public static final fun createFileLoader (Ljava/lang/String;Ljava/lang/String;Z)Lcom/facebook/react/bridge/JSBundleLoader;
 	public abstract fun loadScript (Lcom/facebook/react/bridge/JSBundleLoaderDelegate;)Ljava/lang/String;
 }
 
+public final class com/facebook/react/bridge/JSBundleLoader$Companion {
+	public final fun createAssetLoader (Landroid/content/Context;Ljava/lang/String;Z)Lcom/facebook/react/bridge/JSBundleLoader;
+	public final fun createCachedBundleFromNetworkLoader (Ljava/lang/String;Ljava/lang/String;)Lcom/facebook/react/bridge/JSBundleLoader;
+	public final fun createCachedSplitBundleFromNetworkLoader (Ljava/lang/String;Ljava/lang/String;)Lcom/facebook/react/bridge/JSBundleLoader;
+	public final fun createFileLoader (Ljava/lang/String;)Lcom/facebook/react/bridge/JSBundleLoader;
+	public final fun createFileLoader (Ljava/lang/String;Ljava/lang/String;Z)Lcom/facebook/react/bridge/JSBundleLoader;
+}
+
 public abstract interface class com/facebook/react/bridge/JSBundleLoaderDelegate {
 	public abstract fun loadScriptFromAssets (Landroid/content/res/AssetManager;Ljava/lang/String;Z)V
 	public abstract fun loadScriptFromFile (Ljava/lang/String;Ljava/lang/String;Z)V
diff --git a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/bridge/JSBundleLoader.java b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/bridge/JSBundleLoader.java
deleted file mode 100644
index a066069f30d..00000000000
--- a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/bridge/JSBundleLoader.java
+++ /dev/null
@@ -1,99 +0,0 @@
-/*
- * 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.
- */
-
-package com.facebook.react.bridge;
-
-import android.content.Context;
-import com.facebook.infer.annotation.Nullsafe;
-import com.facebook.react.common.DebugServerException;
-import java.util.Objects;
-
-/** A class that stores JS bundle information and allows a {@link JSBundleLoaderDelegate}. */
-@Nullsafe(Nullsafe.Mode.LOCAL)
-public abstract class JSBundleLoader {
-
-  /**
-   * This loader is recommended one for release version of your app. In that case local JS executor
-   * should be used. JS bundle will be read from assets in native code to save on passing large
-   * strings from java to native memory.
-   */
-  public static JSBundleLoader createAssetLoader(
-      final Context context, final String assetUrl, final boolean loadSynchronously) {
-    return new JSBundleLoader() {
-      @Override
-      public String loadScript(JSBundleLoaderDelegate delegate) {
-        delegate.loadScriptFromAssets(context.getAssets(), assetUrl, loadSynchronously);
-        return assetUrl;
-      }
-    };
-  }
-
-  /**
-   * This loader loads bundle from file system. The bundle will be read in native code to save on
-   * passing large strings from java to native memory.
-   */
-  public static JSBundleLoader createFileLoader(final String fileName) {
-    return createFileLoader(fileName, fileName, false);
-  }
-
-  public static JSBundleLoader createFileLoader(
-      final String fileName, final String assetUrl, final boolean loadSynchronously) {
-    return new JSBundleLoader() {
-      @Override
-      public String loadScript(JSBundleLoaderDelegate delegate) {
-        delegate.loadScriptFromFile(fileName, assetUrl, loadSynchronously);
-        return fileName;
-      }
-    };
-  }
-
-  /**
-   * This loader is used when bundle gets reloaded from dev server. In that case loader expect JS
-   * bundle to be prefetched and stored in local file. We do that to avoid passing large strings
-   * between java and native code and avoid allocating memory in java to fit whole JS bundle in it.
-   * Providing correct {@param sourceURL} of downloaded bundle is required for JS stacktraces to
-   * work correctly and allows for source maps to correctly symbolize those.
-   */
-  public static JSBundleLoader createCachedBundleFromNetworkLoader(
-      final String sourceURL, final String cachedFileLocation) {
-    return new JSBundleLoader() {
-      @Override
-      public String loadScript(JSBundleLoaderDelegate delegate) {
-        try {
-          delegate.loadScriptFromFile(cachedFileLocation, sourceURL, false);
-          return sourceURL;
-        } catch (Exception e) {
-          throw DebugServerException.makeGeneric(
-              sourceURL, Objects.toString(e.getMessage(), ""), e);
-        }
-      }
-    };
-  }
-
-  /**
-   * Same as {{@link JSBundleLoader#createCachedBundleFromNetworkLoader(String, String)}}, but for
-   * split bundles in development.
-   */
-  public static JSBundleLoader createCachedSplitBundleFromNetworkLoader(
-      final String sourceURL, final String cachedFileLocation) {
-    return new JSBundleLoader() {
-      @Override
-      public String loadScript(JSBundleLoaderDelegate delegate) {
-        try {
-          delegate.loadSplitBundleFromFile(cachedFileLocation, sourceURL);
-          return sourceURL;
-        } catch (Exception e) {
-          throw DebugServerException.makeGeneric(
-              sourceURL, Objects.toString(e.getMessage(), ""), e);
-        }
-      }
-    };
-  }
-
-  /** Loads the script, returning the URL of the source it loaded. */
-  public abstract String loadScript(JSBundleLoaderDelegate delegate);
-}
diff --git a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/bridge/JSBundleLoader.kt b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/bridge/JSBundleLoader.kt
new file mode 100644
index 00000000000..52c69a3d39a
--- /dev/null
+++ b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/bridge/JSBundleLoader.kt
@@ -0,0 +1,99 @@
+/*
+ * 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.
+ */
+
+package com.facebook.react.bridge
+
+import android.content.Context
+import com.facebook.react.common.DebugServerException
+
+/** A class that stores JS bundle information and allows a [JSBundleLoaderDelegate]. */
+public abstract class JSBundleLoader {
+
+  /** Loads the script, returning the URL of the source it loaded. */
+  public abstract fun loadScript(delegate: JSBundleLoaderDelegate): String
+
+  public companion object {
+    /**
+     * This loader is recommended one for release version of your app. In that case local JS
+     * executor should be used. JS bundle will be read from assets in native code to save on passing
+     * large strings from java to native memory.
+     */
+    @JvmStatic
+    public fun createAssetLoader(
+        context: Context,
+        assetUrl: String,
+        loadSynchronously: Boolean
+    ): JSBundleLoader =
+        object : JSBundleLoader() {
+          override fun loadScript(delegate: JSBundleLoaderDelegate): String {
+            delegate.loadScriptFromAssets(context.assets, assetUrl, loadSynchronously)
+            return assetUrl
+          }
+        }
+
+    /**
+     * This loader loads bundle from file system. The bundle will be read in native code to save on
+     * passing large strings from java to native memory.
+     */
+    @JvmStatic
+    public fun createFileLoader(fileName: String): JSBundleLoader =
+        createFileLoader(fileName, fileName, false)
+
+    @JvmStatic
+    public fun createFileLoader(
+        fileName: String,
+        assetUrl: String,
+        loadSynchronously: Boolean
+    ): JSBundleLoader =
+        object : JSBundleLoader() {
+          override fun loadScript(delegate: JSBundleLoaderDelegate): String {
+            delegate.loadScriptFromFile(fileName, assetUrl, loadSynchronously)
+            return fileName
+          }
+        }
+
+    /**
+     * This loader is used when bundle gets reloaded from dev server. In that case loader expect JS
+     * bundle to be prefetched and stored in local file. We do that to avoid passing large strings
+     * between java and native code and avoid allocating memory in java to fit whole JS bundle in
+     * it. Providing correct [sourceURL] of downloaded bundle is required for JS stacktraces to work
+     * correctly and allows for source maps to correctly symbolize those.
+     */
+    @JvmStatic
+    public fun createCachedBundleFromNetworkLoader(
+        sourceURL: String,
+        cachedFileLocation: String
+    ): JSBundleLoader =
+        object : JSBundleLoader() {
+          override fun loadScript(delegate: JSBundleLoaderDelegate): String {
+            return try {
+              delegate.loadScriptFromFile(cachedFileLocation, sourceURL, false)
+              sourceURL
+            } catch (e: Exception) {
+              throw DebugServerException.makeGeneric(sourceURL, e.message.orEmpty(), e)
+            }
+          }
+        }
+
+    /** Same as [createCachedBundleFromNetworkLoader], but for split bundles in development. */
+    @JvmStatic
+    public fun createCachedSplitBundleFromNetworkLoader(
+        sourceURL: String,
+        cachedFileLocation: String
+    ): JSBundleLoader =
+        object : JSBundleLoader() {
+          override fun loadScript(delegate: JSBundleLoaderDelegate): String {
+            return try {
+              delegate.loadSplitBundleFromFile(cachedFileLocation, sourceURL)
+              sourceURL
+            } catch (e: Exception) {
+              throw DebugServerException.makeGeneric(sourceURL, e.message.orEmpty(), e)
+            }
+          }
+        }
+  }
+}