text: /**
   *    Copyright (C) 2013 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 <deque>
  
  #include "mongo/bson/bsonobj.h"
  #include "mongo/s/client/multi_command_dispatch.h"
  
  namespace mongo {
  
  /**
   * A DBClientMultiCommand uses the client driver (DBClientConnections) to send and recv
   * commands to different hosts in parallel.
   *
   * See MultiCommandDispatch for more details.
   */
  class DBClientMultiCommand : public MultiCommandDispatch {
  public:
      DBClientMultiCommand() : _timeoutMillis(0) {}
  
      ~DBClientMultiCommand();
  
      void addCommand(const ConnectionString& endpoint,
                      StringData dbName,
                      const BSONSerializable& request);
  
      void sendAll();
  
      int numPending() const;
  
      Status recvAny(ConnectionString* endpoint, BSONSerializable* response);
  
      void setTimeoutMillis(int milliSecs);
  
  private:
      // All info associated with an pre- or in-flight command
      struct PendingCommand {
          PendingCommand(const ConnectionString& endpoint, StringData dbName, const BSONObj& cmdObj);
  
          // What to send
          const ConnectionString endpoint;
          const std::string dbName;
          const BSONObj cmdObj;
  
          // Where to send it
          DBClientBase* conn;
  
          // If anything goes wrong
          Status status;
      };
  
      typedef std::deque<PendingCommand*> PendingQueue;
      PendingQueue _pendingCommands;
      int _timeoutMillis;
  };
  }
  