cleanExpired method

Implementation

Future<void> cleanExpired() async {
  if (!hasExpiration) return;

  for (final key in _keysIndex.toList()) {
    final json = CacheServiceCore.getMap(_itemKey(key));
    if (json != null) {
      final entry = _parseFromDisk(json);
      if (entry == null || entry.isExpired) {
        await _removeFromDisk(key);
      }
    } else {
      // 数据不存在，清理索引
      _keysIndex.remove(key);
    }
  }
  await _saveIndex();
}