gcs_view.h

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/* Copyright (c) 2014, 2025, Oracle and/or its affiliates.
 
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   it under the terms of the GNU General Public License, version 2.0,
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   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
 
#ifndef GCS_VIEW_INCLUDED
#define GCS_VIEW_INCLUDED
 
#include <string>
#include <vector>
 
#include "plugin/group_replication/libmysqlgcs/include/mysql/gcs/gcs_group_identifier.h"
#include "plugin/group_replication/libmysqlgcs/include/mysql/gcs/gcs_member_identifier.h"
#include "plugin/group_replication/libmysqlgcs/include/mysql/gcs/gcs_view_identifier.h"
 
/**
  @class Gcs_view
 
  This represents the membership view that a member has from a group.
 
  This objects contains:
  - A list of members that belong to this view.
  - A Gcs_view_identifier identifier object, that uniquely identifies
    this view in time.
  - The members that were in the last view and that left. This shall
    include the local member when it leaves the group.
  - The members that joined, meaning that they were not present in the
    previous view. This includes the local member when it joins a group,
    meaning that a member can be in the list of members and joined.
  - A Gcs_group_identifier to which this view pertains.
 
  There are two ways to obtain this:
  - In the Gcs_control_interface, one should call, at any moment, the
    method Gcs_control_interface::get_current_view.
  - Cache the value received via Gcs_control_event_listener::on_view_changed.
*/
class Gcs_view {
 public:
  /**
    Define error codes associated to the view.
  */
  enum Gcs_view_error_code { OK = 1, MEMBER_EXPELLED };
 
  /**
    Gcs_view constructor.
 
    @param[in] members group members
    @param[in] view_id the view identifier
    @param[in] leaving the members that left from the previous view
    @param[in] joined the new members
    @param[in] group_id the group identifier
  */
 
  explicit Gcs_view(const std::vector<Gcs_member_identifier> &members,
                    const Gcs_view_identifier &view_id,
                    const std::vector<Gcs_member_identifier> &leaving,
                    const std::vector<Gcs_member_identifier> &joined,
                    const Gcs_group_identifier &group_id);
 
  /**
    @param[in] members group members
    @param[in] view_id the view identifier
    @param[in] leaving the members that left from the previous view
    @param[in] joined the new members
    @param[in] group_id the group identifier
    @param[in] error_code error code associated to the view.
  */
 
  explicit Gcs_view(const std::vector<Gcs_member_identifier> &members,
                    const Gcs_view_identifier &view_id,
                    const std::vector<Gcs_member_identifier> &leaving,
                    const std::vector<Gcs_member_identifier> &joined,
                    const Gcs_group_identifier &group_id,
                    Gcs_view::Gcs_view_error_code error_code);
 
  /**
    Gcs_view constructor which does a deep copy of the object passed
    as parameter.
 
    @param[in] view reference to a Gcs_view object
  */
 
  explicit Gcs_view(Gcs_view const &view);
 
  virtual ~Gcs_view();
 
  /**
    @return the current view identifier. This identifier marks a snapshot in
            time and should increase monotonically
  */
 
  const Gcs_view_identifier &get_view_id() const;
 
  /**
    @return the group where this view pertains
  */
 
  const Gcs_group_identifier &get_group_id() const;
 
  /**
    @return the totality of members that currently belong to this group in a
            certain moment in time, denoted by view_id
  */
 
  const std::vector<Gcs_member_identifier> &get_members() const;
 
  /**
    @return the members that left from the view n-1 to the current view n
  */
 
  const std::vector<Gcs_member_identifier> &get_leaving_members() const;
 
  /**
    @return the new members in view from view n-1 to the current view n
  */
 
  const std::vector<Gcs_member_identifier> &get_joined_members() const;
 
  /**
    @return error code associated to the current view.
  */
 
  Gcs_view::Gcs_view_error_code get_error_code() const;
 
  /*
    @param[in] address Member's identifier which is usually its address
    @return the member whose identifier matches the one provided as
            parameter
  */
 
  const Gcs_member_identifier *get_member(const std::string &member_id) const;
 
  /*
    @param[in] member_id Member's identifier which is usually its address
    @return whether there is a member whose identifier matches the one
            provided as parameter
  */
 
  bool has_member(const std::string &member_id) const;
 
 private:
  std::vector<Gcs_member_identifier> *m_members;
  Gcs_view_identifier *m_view_id;
  std::vector<Gcs_member_identifier> *m_leaving;
  std::vector<Gcs_member_identifier> *m_joined;
  Gcs_group_identifier *m_group_id;
  Gcs_view::Gcs_view_error_code m_error_code;
 
  /*
    Auxiliary function used by constructors.
  */
  void clone(const std::vector<Gcs_member_identifier> &members,
             const Gcs_view_identifier &view_id,
             const std::vector<Gcs_member_identifier> &leaving,
             const std::vector<Gcs_member_identifier> &joined,
             const Gcs_group_identifier &group_id,
             Gcs_view::Gcs_view_error_code error_code);
 
  /*
    Disabling the assignment operator.
  */
  Gcs_view &operator=(Gcs_view const &);
};
 
#endif  // GCS_VIEW_INCLUDED