include/hbase/utils/user-util.h

/*
 * 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.
 *
 */

#pragma once

#include <mutex>
#include <string>

namespace hbase {

/**
 * @brief Class to help with user/group information.
 *
 * This class will get the current user, and information about them. It caches
 * the user information after the first invocation.
 */
class UserUtil {
 public:
  /**
   * Constructor.
   */
  UserUtil();

  /**
   * Get the username of the user owning this process. This is thread safe and
   * lockless for every invocation other than the first one.
   */
  std::string user_name(bool secure = false);

 private:
  /**
   * Compute the username. This will block.
   */
  void compute_user_name(bool secure);
  std::once_flag once_flag_;
  std::string user_name_;
};
}  // namespace hbase