text: /**
   *    Copyright 2015 MongoDB Inc.
   *
   *    This program is free software: you can redistribute it and/or  modify
   *    it under the terms of the GNU Affero General Public License, version 3,
   *    as published by the Free Software Foundation.
   *
   *    This program is distributed in the hope that it will be useful,
   *    but WITHOUT ANY WARRANTY; without even the implied warranty of
   *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *    GNU Affero General Public License for more details.
   *
   *    You should have received a copy of the GNU Affero General Public License
   *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
   *
   *    As a special exception, the copyright holders give permission to link the
   *    code of portions of this program with the OpenSSL library under certain
   *    conditions as described in each individual source file and distribute
   *    linked combinations including the program with the OpenSSL library. You
   *    must comply with the GNU Affero General Public License in all respects for
   *    all of the code used other than as permitted herein. If you modify file(s)
   *    with this exception, you may extend this exception to your version of the
   *    file(s), but you are not obligated to do so. If you do not wish to do so,
   *    delete this exception statement from your version. If you delete this
   *    exception statement from all source files in the program, then also delete
   *    it in the license file.
   */
  
  #pragma once
  
  #include "mongo/base/status.h"
  #include "mongo/stdx/functional.h"
  
  namespace mongo {
  namespace repl {
  
  /**
   * Used by cloner test fixture to centralize life cycle testing.
   *
   * Life cycle interface for collection and database cloners.
   */
  class BaseCloner {
  public:
      /**
       * Callback function to report final status of cloning.
       */
      using CallbackFn = stdx::function<void(const Status&)>;
  
      virtual ~BaseCloner() {}
  
      /**
       * Returns diagnostic information.
       */
      virtual std::string getDiagnosticString() const = 0;
  
      /**
       * Returns true if the cloner has been started (but has not completed).
       */
      virtual bool isActive() const = 0;
  
      /**
       * Starts cloning by scheduling initial command to be run by the executor.
       */
      virtual Status startup() noexcept = 0;
  
      /**
       * Cancels current remote command request.
       * Returns immediately if cloner is not active.
       *
       * Callback function may be invoked with an ErrorCodes::CallbackCanceled status.
       */
      virtual void shutdown() = 0;
  
      /**
       * Waits for active remote commands and database worker to complete.
       * Returns immediately if cloner is not active.
       */
      virtual void join() = 0;
  };
  
  }  // namespace repl
  }  // namespace mongo
  