server_version_transition.h

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#ifndef DD__BOOTSTRAP__SERVER_VERSION_TRANSITION_INCLUDED
#define DD__BOOTSTRAP__SERVER_VERSION_TRANSITION_INCLUDED
 
#include "my_sys.h"  // My_server_version
 
namespace dd::bootstrap {
 
/**
  Decide whether a stored server version may move to a target server version.
 
  This class is intentionally independent of DD_properties and THD. Tests can
  construct it directly from persisted source-version details and target
  metadata, inspect the pure Result from evaluate(), and leave error-log
  side-effects to check_and_report().
*/
class Server_version_transition {
 public:
  enum class Result {
    ACCEPTED,
    INVALID_SERVER_UPGRADE_NOT_LTS,
    INVALID_SERVER_UPGRADE_SKIPS_LTS_LINEAGE,
    BEYOND_SERVER_UPGRADE_THRESHOLD,
    INVALID_SERVER_DOWNGRADE_NOT_PATCH,
    NO_PATCH_DOWNGRADE_FOR_INNOVATION_RELEASES,
    BEYOND_SERVER_DOWNGRADE_THRESHOLD
  };
 
  Server_version_transition(My_server_version source, My_server_version target);
 
  Result evaluate() const;
 
  /**
    Emit the matching error-log message if evaluate() rejects the transition.
 
    @retval false  Transition accepted.
    @retval true   Transition rejected and error reported.
  */
  bool check_and_report() const;
 
 private:
  My_server_version m_source;
  My_server_version m_target;
};
 
}  // namespace dd::bootstrap
 
#endif  // DD__BOOTSTRAP__SERVER_VERSION_TRANSITION_INCLUDED