text: /**
   *    Copyright (C) 2017 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 <boost/optional.hpp>
  #include <vector>
  
  #include "mongo/base/disallow_copying.h"
  #include "mongo/base/status_with.h"
  #include "mongo/bson/bsonobj.h"
  #include "mongo/db/cursor_id.h"
  #include "mongo/executor/task_executor.h"
  #include "mongo/s/query/cluster_client_cursor_params.h"
  #include "mongo/stdx/mutex.h"
  #include "mongo/util/net/hostandport.h"
  #include "mongo/util/time_support.h"
  
  namespace mongo {
  
  class CursorResponse;
  
  /**
   * Establishes cursors on the remote shards by issuing requests in parallel, using the readPref to
   * select a host within each shard.
   *
   * If any of the cursors fail to be established, this function performs cleanup by sending
   * killCursors to any cursors that were established, then throws the error. If the namespace
   * represents a view, an exception containing a ResolvedView is thrown. Calling code can then
   * attempt to establish cursors against the base collection using this view.
   *
   * On success, the ownership of the cursors is transferred to the caller. This means the caller is
   * now responsible for either exhausting the cursors or sending killCursors to them.
   *
   * @param allowPartialResults: If true, unreachable hosts are ignored, and only cursors established
   *                             on reachable hosts are returned.
   *
   */
  std::vector<ClusterClientCursorParams::RemoteCursor> establishCursors(
      OperationContext* opCtx,
      executor::TaskExecutor* executor,
      const NamespaceString& nss,
      const ReadPreferenceSetting readPref,
      const std::vector<std::pair<ShardId, BSONObj>>& remotes,
      bool allowPartialResults);
  
  }  // namespace mongo
  