text: /**
   *    Copyright (C) 2014 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/disallow_copying.h"
  #include "mongo/bson/timestamp.h"
  #include "mongo/db/repl/optime.h"
  #include "mongo/util/time_support.h"
  
  namespace mongo {
  
  class BSONObj;
  class OID;
  class OperationContext;
  class Status;
  struct HostAndPort;
  template <typename T>
  class StatusWith;
  
  namespace repl {
  
  class LastVote;
  
  /**
   * This class represents the interface the ReplicationCoordinator uses to interact with the
   * rest of the system.  All functionality of the ReplicationCoordinatorImpl that would introduce
   * dependencies on large sections of the server code and thus break the unit testability of
   * ReplicationCoordinatorImpl should be moved here.
   */
  class ReplicationCoordinatorExternalState {
      MONGO_DISALLOW_COPYING(ReplicationCoordinatorExternalState);
  
  public:
      ReplicationCoordinatorExternalState();
      virtual ~ReplicationCoordinatorExternalState();
  
      /**
       * Starts the background sync, producer, and sync source feedback threads
       *
       * NOTE: Only starts threads if they are not already started,
       */
      virtual void startThreads() = 0;
  
      /**
       * Starts the Master/Slave threads and sets up logOp
       */
      virtual void startMasterSlave(OperationContext* txn) = 0;
  
      /**
       * Performs any necessary external state specific shutdown tasks, such as cleaning up
       * the threads it started.
       */
      virtual void shutdown() = 0;
  
      /**
       * Creates the oplog and writes the first entry.
       */
      virtual void initiateOplog(OperationContext* txn) = 0;
  
      /**
       * Simple wrapper around SyncSourceFeedback::forwardSlaveProgress.  Signals to the
       * SyncSourceFeedback thread that it needs to wake up and send a replSetUpdatePosition
       * command upstream.
       */
      virtual void forwardSlaveProgress() = 0;
  
      /**
       * Queries the singleton document in local.me.  If it exists and our hostname has not
       * changed since we wrote, returns the RID stored in the object.  If the document does not
       * exist or our hostname doesn't match what was recorded in local.me, generates a new OID
       * to use as our RID, stores it in local.me, and returns it.
       */
      virtual OID ensureMe(OperationContext*) = 0;
  
      /**
       * Returns true if "host" is one of the network identities of this node.
       */
      virtual bool isSelf(const HostAndPort& host) = 0;
  
      /**
       * Gets the replica set config document from local storage, or returns an error.
       */
      virtual StatusWith<BSONObj> loadLocalConfigDocument(OperationContext* txn) = 0;
  
      /**
       * Stores the replica set config document in local storage, or returns an error.
       */
      virtual Status storeLocalConfigDocument(OperationContext* txn, const BSONObj& config) = 0;
  
      /**
       * Gets the replica set lastVote document from local storage, or returns an error.
       */
      virtual StatusWith<LastVote> loadLocalLastVoteDocument(OperationContext* txn) = 0;
  
      /**
       * Stores the replica set lastVote document in local storage, or returns an error.
       */
      virtual Status storeLocalLastVoteDocument(OperationContext* txn, const LastVote& lastVote) = 0;
  
      /**
       * Sets the global opTime to be 'newTime'.
       */
      virtual void setGlobalTimestamp(const Timestamp& newTime) = 0;
  
      /**
       * Gets the last optime of an operation performed on this host, from stable
       * storage.
       */
      virtual StatusWith<OpTime> loadLastOpTime(OperationContext* txn) = 0;
  
      /**
       * Returns the HostAndPort of the remote client connected to us that initiated the operation
       * represented by "txn".
       */
      virtual HostAndPort getClientHostAndPort(const OperationContext* txn) = 0;
  
      /**
       * Closes all connections except those marked with the keepOpen property, which should
       * just be connections used for heartbeating.
       * This is used during stepdown, and transition out of primary.
       */
      virtual void closeConnections() = 0;
  
      /**
       * Kills all operations that have a Client that is associated with an incoming user
       * connection.  Used during stepdown.
       */
      virtual void killAllUserOperations(OperationContext* txn) = 0;
  
      /**
       * Clears all cached sharding metadata on this server.  This is called after stepDown to
       * ensure that if the node becomes primary again in the future it will reload an up-to-date
       * version of the sharding data.
       */
      virtual void clearShardingState() = 0;
  
      /**
       * Notifies the bgsync and syncSourceFeedback threads to choose a new sync source.
       */
      virtual void signalApplierToChooseNewSyncSource() = 0;
  
      /**
       * Returns an OperationContext, owned by the caller, that may be used in methods of
       * the same instance that require an OperationContext.
       */
      virtual OperationContext* createOperationContext(const std::string& threadName) = 0;
  
      /**
       * Drops all temporary collections on all databases except "local".
       *
       * The implementation may assume that the caller has acquired the global exclusive lock
       * for "txn".
       */
      virtual void dropAllTempCollections(OperationContext* txn) = 0;
  };
  
  }  // namespace repl
  }  // namespace mongo
  