content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements. See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License. You may obtain a copy of the License at
   *
   *    http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.kafka.common.config.internals;
  
  import org.apache.kafka.common.config.ConfigException;
  
  import java.nio.file.Files;
  import java.nio.file.Path;
  import java.nio.file.Paths;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.List;
  
  public class AllowedPaths {
      private final List<Path> allowedPaths;
  
      /**
       * Constructs AllowedPaths with a list of Paths retrieved from {@code configValue}.
       * @param configValue {@code allowed.paths} config value which is a string containing comma separated list of paths
       * @throws ConfigException if any of the given paths is not absolute or does not exist.
       */
      public AllowedPaths(String configValue) {
          this.allowedPaths = getAllowedPaths(configValue);
      }
  
      private List<Path> getAllowedPaths(String configValue) {
          if (configValue != null && !configValue.isEmpty()) {
              List<Path> allowedPaths = new ArrayList<>();
  
              Arrays.stream(configValue.split(",")).forEach(b -> {
                  Path normalisedPath = Paths.get(b).normalize();
  
                  if (!normalisedPath.isAbsolute()) {
                      throw new ConfigException("Path " + normalisedPath + " is not absolute");
                  } else if (!Files.exists(normalisedPath)) {
                      throw new ConfigException("Path " + normalisedPath + " does not exist");
                  } else {
                      allowedPaths.add(normalisedPath);
                  }
              });
  
              return allowedPaths;
          }
  
          return null;
      }
  
      /**
       * Checks if the given {@code path} resides in the configured {@code allowed.paths}.
       * If {@code allowed.paths} is not configured, the given Path is returned as allowed.
       * @param path the Path to check if allowed
       * @return Path that can be accessed or null if the given Path does not reside in the configured {@code allowed.paths}.
       */
      public Path parseUntrustedPath(String path) {
          Path parsedPath = Paths.get(path);
  
          if (allowedPaths != null) {
              Path normalisedPath = parsedPath.normalize();
              long allowed = allowedPaths.stream().filter(normalisedPath::startsWith).count();
              if (allowed == 0) {
                  return null;
              }
              return normalisedPath;
          }
  
          return parsedPath;
      }
  }
  