recovery_metadata_observer.h

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/* Copyright (c) 2023, 2025, Oracle and/or its affiliates.
 
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   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.
 
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#ifndef RECOVERY_METADATA_OBSERVER_H
#define RECOVERY_METADATA_OBSERVER_H
 
#include "plugin/group_replication/include/plugin_observers/group_event_observer.h"
#include "plugin/group_replication/libmysqlgcs/include/mysql/gcs/gcs_member_identifier.h"
 
/**
  @class Recovery_metadata_observer
  This class is used by:
  1. joiner: to keep track of all leaving recovery metadata donors,
             so that joiner can error out if no donor is available.
  2. recovery metadata donors:
        to keep track of all leaving recovery metadata donors,
        so that other donor can send metadata if any exisiting
        donor has left before successfully sending data.
*/
class Recovery_metadata_observer : public Group_event_observer {
 public:
  /**
    Constructor
    Register observer to get notification on view change.
  */
  Recovery_metadata_observer();
 
  /**
    Destructor.
    Unregister observers
  */
  virtual ~Recovery_metadata_observer() override;
 
 private:
  /**
    Executed after view install and before primary election
 
    @param joining            members joining the group
    @param leaving            members leaving the group
    @param group              members in the group
    @param is_leaving         is the member leaving
    @param[out] skip_election skip primary election on view
    @param[out] election_mode election mode
    @param[out] suggested_primary what should be the next primary to elect
  */
  int after_view_change(const std::vector<Gcs_member_identifier> &joining,
                        const std::vector<Gcs_member_identifier> &leaving,
                        const std::vector<Gcs_member_identifier> &group,
                        bool is_leaving, bool *skip_election,
                        enum_primary_election_mode *election_mode,
                        std::string &suggested_primary) override;
 
  /**
    Executed after primary election
 
    @param primary_uuid    the elected primary
    @param primary_change_status if the primary changed after the election
    @param election_mode   what was the election mode
    @param error           if there was and error on the process
  */
  int after_primary_election(
      std::string primary_uuid,
      enum_primary_election_primary_change_status primary_change_status,
      enum_primary_election_mode election_mode, int error) override;
 
  /**
    Executed before the message is processed
 
    @param message             The GCS message
    @param message_origin      The member that sent this message (address)
    @param[out] skip_message   skip message handling if true
  */
  int before_message_handling(const Plugin_gcs_message &message,
                              const std::string &message_origin,
                              bool *skip_message) override;
};
 
#endif /* RECOVERY_METADATA_OBSERVER_H */