Use AssetManagerString on Android (#54384)

Summary:
Pull Request resolved: #54384

Delegate to the existing AssetManager loading logic in RN Android in the platform-specific ResourceLoader bits.

Changelog: [Internal]

Reviewed By: christophpurrer

Differential Revision: D86099684

fbshipit-source-id: 43d33aa9b4f353e817966d76b8272950d954feab

Author: javache

packages/react-native/ReactAndroid/src/main/jni/react/jni/JSLoader.h

@@ -10,11 +10,12 @@
 #include <string>
 
 #include <android/asset_manager.h>
-#include <cxxreact/JSExecutor.h>
 #include <fbjni/fbjni.h>
 
 namespace facebook::react {
 
+class JSBigString;
+
 struct JAssetManager : jni::JavaClass<JAssetManager> {
   static constexpr auto kJavaDescriptor = "Landroid/content/res/AssetManager;";
 };

packages/react-native/ReactCxxPlatform/react/io/ResourceLoader.cpp

@@ -6,9 +6,9 @@
  */
 
 #include "ResourceLoader.h"
+
+#include <cxxreact/JSBigString.h>
 #include <glog/logging.h>
-#include <fstream>
-#include <sstream>
 
 namespace facebook::react {
 /* static */ bool ResourceLoader::isAbsolutePath(const std::string& path) {
@@ -32,19 +32,13 @@ namespace facebook::react {
   return isResourceFile(path);
 }
 
-/* static */ std::string ResourceLoader::getFileContents(
+/* static */ std::unique_ptr<const JSBigString> ResourceLoader::getFileContents(
     const std::string& path) {
-  if (isAbsolutePath(path)) {
-    std::ifstream file(path, std::ios::binary);
-    if (!file.good()) {
-      return getResourceFileContents(path);
-    }
-    std::stringstream buffer;
-    buffer << file.rdbuf();
-    return buffer.str();
+  if (isResourceFile(path)) {
+    return getResourceFileContents(path);
+  } else {
+    return JSBigFileString::fromPath(path);
   }
-
-  return getResourceFileContents(path);
 }
 
 /* static */ std::filesystem::path ResourceLoader::getCacheDirectory(

packages/react-native/ReactCxxPlatform/react/io/ResourceLoader.h

@@ -11,18 +11,21 @@
 #include <string>
 
 namespace facebook::react {
+
+class JSBigString;
+
 class ResourceLoader {
  public:
   static bool isDirectory(const std::string &path);
   static bool isFile(const std::string &path);
   static bool isAbsolutePath(const std::string &path);
-  static std::string getFileContents(const std::string &path);
+  static std::unique_ptr<const JSBigString> getFileContents(const std::string &path);
   static std::filesystem::path getCacheDirectory(const std::string &path = std::string());
 
  protected:
   static bool isResourceDirectory(const std::string &path);
   static bool isResourceFile(const std::string &path);
-  static std::string getResourceFileContents(const std::string &path);
+  static std::unique_ptr<const JSBigString> getResourceFileContents(const std::string &path);
 
  private:
   static constexpr const auto CACHE_DIR = ".react-native-cxx-cache";

packages/react-native/ReactCxxPlatform/react/io/platform/android/ResourceLoader.cpp

@@ -10,12 +10,15 @@
 
 #include <android/asset_manager.h>
 #include <android/asset_manager_jni.h>
+#include <cxxreact/JSBigString.h>
 #include <fbjni/fbjni.h>
+#include <react/jni/JSLoader.h>
 #include <react/jni/JniHelper.h>
 
 namespace facebook::react {
 
 namespace {
+
 AAssetManager* assetManager_ = nullptr;
 
 AAssetManager* getAssetManager() {
@@ -52,17 +55,9 @@ bool ResourceLoader::isResourceFile(const std::string& path) {
   return true;
 }
 
-std::string ResourceLoader::getResourceFileContents(const std::string& path) {
-  auto asset = AAssetManager_open(
-      getAssetManager(), path.c_str(), AASSET_MODE_STREAMING);
-  if (asset == nullptr) {
-    throw std::runtime_error("File not found " + path);
-  }
-
-  std::string result(
-      (const char*)AAsset_getBuffer(asset), (size_t)AAsset_getLength(asset));
-  AAsset_close(asset);
-  return result;
+std::unique_ptr<const JSBigString> ResourceLoader::getResourceFileContents(
+    const std::string& path) {
+  return loadScriptFromAssets(getAssetManager(), path);
 }
 
 std::filesystem::path ResourceLoader::getCacheRootPath() {

packages/react-native/ReactCxxPlatform/react/io/platform/cxx/ResourceLoader.cpp

@@ -5,11 +5,10 @@
  * LICENSE file in the root directory of this source tree.
  */
 
+#include <cxxreact/JSBigString.h>
 #include <react/io/ResourceLoader.h>
 
 #include <cassert>
-#include <fstream>
-#include <sstream>
 
 namespace facebook::react {
 
@@ -21,17 +20,12 @@ bool ResourceLoader::isResourceFile(const std::string& path) {
   return std::filesystem::exists(path) && !std::filesystem::is_directory(path);
 }
 
-std::string ResourceLoader::getResourceFileContents(const std::string& path) {
-  std::ifstream file(path, std::ios::binary);
-  if (!file.good()) {
-    throw std::runtime_error("File not found " + path);
-  }
-  std::stringstream buffer;
-  buffer << file.rdbuf();
-  return buffer.str();
+/* static */ std::unique_ptr<const JSBigString>
+ResourceLoader::getResourceFileContents(const std::string& path) {
+  return JSBigFileString::fromPath(path);
 }
 
-std::filesystem::path ResourceLoader::getCacheRootPath() {
+/* static */ std::filesystem::path ResourceLoader::getCacheRootPath() {
   return std::filesystem::temp_directory_path();
 }
 } // namespace facebook::react

packages/react-native/ReactCxxPlatform/react/jni/JniHelper.cpp

@@ -5,6 +5,8 @@
  * LICENSE file in the root directory of this source tree.
  */
 
+#include "JniHelper.h"
+
 #include <fbjni/Context.h>
 #include <fbjni/fbjni.h>
 

packages/react-native/ReactCxxPlatform/react/runtime/ReactHost.cpp

@@ -484,9 +484,7 @@ bool ReactHost::loadScriptFromDevServer() {
 bool ReactHost::loadScriptFromBundlePath(const std::string& bundlePath) {
   try {
     LOG(INFO) << "Loading JS bundle from bundle path: " << bundlePath;
-    // TODO: use platform-native asset loading strategy
-    auto script = std::make_unique<JSBigStdString>(
-        ResourceLoader::getFileContents(bundlePath));
+    auto script = ResourceLoader::getFileContents(bundlePath);
     reactInstance_->loadScript(std::move(script), bundlePath);
     LOG(INFO) << "Loaded JS bundle from bundle path: " << bundlePath;
     return true;