text: // Copyright (c) 2017-2019 The Crown Core developers
  // Distributed under the MIT software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #include <wallet/walletutil.h>
  
  #include <logging.h>
  #include <util/system.h>
  
  bool ExistsBerkeleyDatabase(const fs::path& path);
  #ifdef USE_SQLITE
  bool ExistsSQLiteDatabase(const fs::path& path);
  #else
  #   define ExistsSQLiteDatabase(path)  (false)
  #endif
  
  fs::path GetWalletDir()
  {
      fs::path path;
  
      if (gArgs.IsArgSet("-walletdir")) {
          path = gArgs.GetArg("-walletdir", "");
          if (!fs::is_directory(path)) {
              // If the path specified doesn't exist, we return the deliberately
              // invalid empty string.
              path = "";
          }
      } else {
          path = GetDataDir();
          // If a wallets directory exists, use that, otherwise default to GetDataDir
          if (fs::is_directory(path / "wallets")) {
              path /= "wallets";
          }
      }
  
      return path;
  }
  
  std::vector<fs::path> ListWalletDir()
  {
      const fs::path wallet_dir = GetWalletDir();
      const size_t offset = wallet_dir.string().size() + 1;
      std::vector<fs::path> paths;
      boost::system::error_code ec;
  
      for (auto it = fs::recursive_directory_iterator(wallet_dir, ec); it != fs::recursive_directory_iterator(); it.increment(ec)) {
          if (ec) {
              if (fs::is_directory(*it)) {
                  it.no_push();
                  LogPrintf("%s: %s %s -- skipping.\n", __func__, ec.message(), it->path().string());
              } else {
                  LogPrintf("%s: %s %s\n", __func__, ec.message(), it->path().string());
              }
              continue;
          }
  
          try {
              // Get wallet path relative to walletdir by removing walletdir from the wallet path.
              // This can be replaced by boost::filesystem::lexically_relative once boost is bumped to 1.60.
              const fs::path path = it->path().string().substr(offset);
  
              if (it->status().type() == fs::directory_file &&
                  (ExistsBerkeleyDatabase(it->path()) || ExistsSQLiteDatabase(it->path()))) {
                  // Found a directory which contains wallet.dat btree file, add it as a wallet.
                  paths.emplace_back(path);
              } else if (it.level() == 0 && it->symlink_status().type() == fs::regular_file && ExistsBerkeleyDatabase(it->path())) {
                  if (it->path().filename() == "wallet.dat") {
                      // Found top-level wallet.dat btree file, add top level directory ""
                      // as a wallet.
                      paths.emplace_back();
                  } else {
                      // Found top-level btree file not called wallet.dat. Current crown
                      // software will never create these files but will allow them to be
                      // opened in a shared database environment for backwards compatibility.
                      // Add it to the list of available wallets.
                      paths.emplace_back(path);
                  }
              }
          } catch (const std::exception& e) {
              LogPrintf("%s: Error scanning %s: %s\n", __func__, it->path().string(), e.what());
              it.no_push();
          }
      }
  
      return paths;
  }
  
  bool IsFeatureSupported(int wallet_version, int feature_version)
  {
      return wallet_version >= feature_version;
  }
  
  WalletFeature GetClosestWalletFeature(int version)
  {
      const std::array<WalletFeature, 8> wallet_features{{FEATURE_LATEST, FEATURE_PRE_SPLIT_KEYPOOL, FEATURE_NO_DEFAULT_KEY, FEATURE_HD_SPLIT, FEATURE_HD, FEATURE_COMPRPUBKEY, FEATURE_WALLETCRYPT, FEATURE_BASE}};
      for (const WalletFeature& wf : wallet_features) {
          if (version >= wf) return wf;
      }
      return static_cast<WalletFeature>(0);
  }
  