building up to React Core (#50766)

Summary:
- Added multiple targets to Package.swift
- WIP: Builds up untill we need to touch files in React/Base

## Changelog:

[INTERNAL] - WIP: prebuilding using Swift packages

Pull Request resolved: #50766

Test Plan: This will be tested in a diff in the stack.

Reviewed By: cortinico

Differential Revision: D74386522

Pulled By: cipolleschi

fbshipit-source-id: 7bac3c21a362c4ef79d0104727cdd3494419012f

Author: chrfalch

packages/react-native/scripts/ios-prebuild/hermes.js

@@ -0,0 +1,89 @@
+/**
+ * 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.
+ *
+ * @flow
+ * @format
+ * @oncall react_native
+ */
+
+const {execSync} = require('child_process');
+const fs = require('fs');
+const path = require('path');
+
+async function prepareHermesArtifactsAsync(
+  version /*:string*/,
+  buildType /*:string*/,
+) /*: Promise<string> */ {
+  // Check if the Hermes artifacts are already downloaded
+  const artifactsPath /*: string*/ = path.resolve(
+    process.cwd(),
+    '.build',
+    'artifacts',
+    'hermes',
+  );
+  if (fs.existsSync(artifactsPath)) {
+    return artifactsPath;
+  }
+
+  // Download the Hermes artifacts
+  const url = getHermesArtifactsUrl(version, buildType);
+  console.log(`Downloading Hermes artifacts from ${url}...`);
+
+  // download the file pointed to by the URL and store it in the ./.build/artifacts folder on disk
+  await downloadAndExtract(url, artifactsPath);
+  return artifactsPath;
+}
+
+async function downloadAndExtract(url /*:string*/, targetFolder /*:string*/) {
+  const buildDir = path.resolve('.build', 'artifacts');
+  const tarballPath = path.join(buildDir, 'artifact.tar.gz');
+
+  // Ensure build directory exists
+  fs.mkdirSync(targetFolder, {recursive: true});
+
+  console.log(`Downloading file from ${url} to ${tarballPath}...`);
+
+  try {
+    // Download the file using curl via execSync
+    execSync(`curl -L "${url}" -o "${tarballPath}"`, {stdio: 'inherit'});
+
+    console.log('Download complete. Extracting...');
+
+    // Extract the tar.gz using execSync
+    execSync(`tar -xzf "${tarballPath}" -C "${targetFolder}"`, {
+      stdio: 'inherit',
+    });
+
+    // Delete the tarball after extraction
+    fs.unlinkSync(tarballPath);
+
+    console.log('Download and extraction complete.');
+  } catch (error) {
+    if (fs.existsSync(tarballPath)) {
+      fs.unlinkSync(tarballPath);
+    }
+    throw new Error(`Failed to download or extract: ${error.message}`);
+  }
+}
+
+function getHermesArtifactsUrl(
+  version /*:string*/,
+  buildType /*:string*/,
+) /*:string*/ {
+  // Define the URL for the Hermes artifacts
+  // The URL format is:
+  // https://repo1.maven.org/maven2/com/facebook/react/react-native-artifacts/<version>/react-native-artifacts-<version>-hermes-ios-<buildType>.tar.gz
+  // where <version> is the version of React Native and <buildType> is the build type (e.g., "debug" or "release")
+  // The Maven repository URL and namespace
+  // are hardcoded for simplicity, but they could be parameterized if needed
+  const maven_repo_url = 'https://repo1.maven.org/maven2';
+  const namespace = 'com/facebook/react';
+  return `${maven_repo_url}/${namespace}/react-native-artifacts/${version}/react-native-artifacts-${version}-hermes-ios-${buildType}.tar.gz`;
+}
+
+module.exports = {
+  prepareHermesArtifactsAsync,
+};