ArchiveReader.decode constructor

ArchiveReader.decode(Uint8List bytes, ArchiveFormat format)

Decodes bytes as format into an indexed reader. Throws StateError when the archive exceeds maxArchiveBytes or fails to decode.

Implementation

factory ArchiveReader.decode(Uint8List bytes, ArchiveFormat format) {
  if (bytes.length > maxArchiveBytes) {
    throw StateError(
      'Archive is too large to read in memory '
      '(${bytes.length} bytes > $maxArchiveBytes byte limit)',
    );
  }
  // ZipDecoder is lenient with garbage input (it yields an empty archive);
  // every real ZIP — even an empty one — starts with a PK record
  // signature, so reject non-ZIP bytes up front (omp's framing rejects a
  // missing end-of-central-directory record the same way).
  if (format == ArchiveFormat.zip &&
      (bytes.length < 2 || bytes[0] != 0x50 || bytes[1] != 0x4B)) {
    throw StateError('Cannot read archive: not a ZIP file');
  }
  final Archive decoded;
  try {
    decoded = switch (format) {
      ArchiveFormat.zip => ZipDecoder().decodeBytes(bytes),
      ArchiveFormat.tar => TarDecoder().decodeBytes(bytes),
      ArchiveFormat.tarGz => TarDecoder().decodeBytes(
        GZipDecoder().decodeBytes(bytes),
      ),
    };
  } on Object catch (error) {
    throw StateError('Cannot read archive: $error');
  }

  final entries = <_IndexEntry>[];
  for (final file in decoded.files) {
    final normalizedPath = _normalizeArchiveEntryPath(file.name);
    if (normalizedPath == null) continue;
    final isDirectory =
        !file.isFile || file.name.endsWith('/') || file.name.endsWith('\\');
    entries.add(
      _IndexEntry(
        path: normalizedPath,
        isDirectory: isDirectory,
        size: isDirectory ? 0 : file.size,
        file: isDirectory ? null : file,
      ),
    );
  }
  return ArchiveReader._(format, entries);
}