reverse-engineering-anything/src/domain/nativeConvention.ts

/** Path-segment conventions. These are inferences, not observations of runtime behavior. */

export type NativeRuntimeConvention = "react-native" | "flutter" | "unity";

const foldSegment = (segment: string): string =>
  segment.toLocaleLowerCase("en-US");

const REACT_NATIVE_SEGMENTS = new Set([
  "react.framework",
  "reactnative.framework",
  "libreactnative.so",
  "libreactnativejni.so",
  "libhermes_executor.so",
  "libhermes.so",
  "hermes.framework",
]);
const FLUTTER_SEGMENTS = new Set(["libflutter.so", "flutter.framework"]);
const UNITY_SEGMENTS = new Set(["libunity.so", "unityframework.framework"]);
const DESKTOP_IL2CPP_LIBRARIES = new Set([
  "gameassembly.dll",
  "gameassembly.so",
  "gameassembly.dylib",
  "libil2cpp.so",
]);
/** Unity's predefined script assembly names; asmdef assembly names are project-chosen. */
const UNITY_PREDEFINED_ASSEMBLIES = new Set([
  "assembly-csharp.dll",
  "assembly-csharp-firstpass.dll",
]);

/**
 * A runtime family named by the library filename or a containing framework.
 * A library-named ancestor directory does not establish a convention.
 */
export const nativeRuntimeConvention = (
  path: string,
): NativeRuntimeConvention | null => {
  const segments = path.split("/");
  for (const [index, segment] of segments.entries()) {
    const folded = foldSegment(segment);
    if (index !== segments.length - 1 && !folded.endsWith(".framework"))
      continue;
    if (REACT_NATIVE_SEGMENTS.has(folded)) return "react-native";
    if (FLUTTER_SEGMENTS.has(folded)) return "flutter";
    if (UNITY_SEGMENTS.has(folded)) return "unity";
  }
  return null;
};

/** Swift runtime libraries are `libswift*.dylib` segments, not every dynamic library. */
export const isSwiftRuntimeLibrary = (path: string): boolean =>
  path
    .split("/")
    .some((segment) => /^libswift.+\.dylib$/u.test(foldSegment(segment)));

/** Unity names the pre-IL2CPP managed backup `<Product>_BackUpThisFolder_ButDontShipItWithYourGame`. */
const UNITY_IL2CPP_BACKUP_SUFFIX =
  "_backupthisfolder_butdontshipitwithyourgame";

/**
 * Parse desktop layout conventions once while preserving original path segments.
 * `rootName` is the admitted root directory name; `.` denotes that root in returned directories.
 */
export const desktopPathConventions = (path: string, rootName?: string) => {
  const segments = path.split("/");
  const folded = segments.map(foldSegment);
  let unityManagedDirectory: string | null = null;
  let unityManagedIndex = -1;
  for (let index = 0; index + 2 < folded.length; index++) {
    const segment = folded[index];
    const namedDataDirectory =
      segment !== undefined && segment.length > 5 && segment.endsWith("_data");
    const bundleDataDirectory =
      segment === "data" &&
      folded[index - 1] === "resources" &&
      folded[index - 2] === "contents";
    if (
      (namedDataDirectory || bundleDataDirectory) &&
      folded[index + 1] === "managed"
    ) {
      unityManagedDirectory = segments.slice(0, index + 2).join("/");
      unityManagedIndex = index + 1;
    }
  }
  // The admitted root may itself be the backup folder, so its name precedes the relative segments.
  const rooted =
    rootName === undefined ? folded : [foldSegment(rootName), ...folded];
  const shift = rooted.length - folded.length;
  let unityIl2cppBackupDirectory: string | null = null;
  let unityIl2cppBackupIndex = -1;
  for (let index = 0; index + 1 < rooted.length; index++) {
    const segment = rooted[index] ?? "";
    if (
      segment.length > UNITY_IL2CPP_BACKUP_SUFFIX.length &&
      segment.endsWith(UNITY_IL2CPP_BACKUP_SUFFIX)
    ) {
      unityIl2cppBackupDirectory =
        index < shift ? "." : segments.slice(0, index - shift + 1).join("/");
      unityIl2cppBackupIndex = index - shift;
    }
  }
  const name = folded.at(-1) ?? "";
  return {
    unityIl2cppBackupDirectory,
    unityIl2cppBackupAssembly:
      unityIl2cppBackupIndex === segments.length - 3 &&
      folded[unityIl2cppBackupIndex + 1] === "managed" &&
      UNITY_PREDEFINED_ASSEMBLIES.has(name),
    unityManagedDirectory,
    unityPredefinedAssembly:
      unityManagedIndex === segments.length - 2 &&
      UNITY_PREDEFINED_ASSEMBLIES.has(name),
    il2cppLibrary: DESKTOP_IL2CPP_LIBRARIES.has(name),
    electronArchive:
      folded.at(-2) === "resources" &&
      (name === "app.asar" || name === "default_app.asar"),
    unrealContainer:
      (name.endsWith(".pak") || name.endsWith(".utoc")) &&
      folded.some(
        (segment, index) =>
          segment === "content" &&
          folded[index + 1] === "paks" &&
          index + 2 < folded.length,
      ),
  };
};