gtidset.h

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#ifndef MYSQL_GTID_GTIDSET_H
#define MYSQL_GTID_GTIDSET_H
 
#include <cstddef>
#include <map>
#include <set>
#include <sstream>
 
#include "mysql/gtid/global.h"
#include "mysql/gtid/gtid.h"
#include "mysql/gtid/tag.h"
#include "mysql/gtid/tsid.h"
#include "mysql/utils/nodiscard.h"
 
/// @addtogroup GroupLibsMysqlGtid
/// @{
 
namespace mysql::gtid {
 
/**
 * @brief This class represents a range of transaction identifiers.
 *
 * A transaction identifier is composed of two parts, the UUID and the sequence
 * number.
 *
 * There can be multiple transaction identifiers for a given UUID. When their
 * sequence number are contiguous they can be represented as an interval. This
 * is the class that represents on of those intervals.
 *
 */
class Gno_interval {
 public:
  /// In 'UUID:GNO-GNO', this is the '-'
  static const inline std::string SEPARATOR_GNO_START_END{"-"};
 
 private:
  gno_t m_start{0};
  gno_t m_next_gno_after_end{0};
 
 public:
  virtual ~Gno_interval() = default;
 
  /**
   * @brief Copy assignment.
   *
   * @note This operator does not perform any check about the other interval
   * being valid or not. It is up to the caller to verify that if needed.
   *
   * @param other The other interval to copy.
   * @return Gno_interval& a reference to the copied interval.
   */
  Gno_interval &operator=(const Gno_interval &other);
 
  /**
   * @brief Construct a new Gno_interval object from the other one provided.
   *
   * @note This operator does not perform any check about the other interval
   * being valid or not. It is up to the caller to verify that if needed.
   *
   * @param other The object to copy.
   */
  Gno_interval(const Gno_interval &other);
 
  /**
   * @brief Compares this interval with another one. Returns true if there is a
   * match.
   *
   * @note This operator does not perform any check about the other interval
   * being valid or not. It is up to the caller to verify that if needed, before
   * calling this member function.
   *
   * @param other The other interval to compare this one with.
   * @return true If both intervals match.
   * @return false If intervals do not match.
   */
  virtual bool operator==(const Gno_interval &other) const;
 
  /**
   * @brief Construct a new Gno_interval object.
   *
   * @param start The start of the interval (inclusive).
   * @param end The end of the interval (inclusive).
   */
  Gno_interval(gno_t start, gno_t end);
 
  /**
   * @brief Establishes a total order between two intervals.
   *
   * Total order is determined using the start and end values of
   * the interval.
   *
   * An interval A comes before interval B if its start value is smaller
   * than the start value of B.
   *
   * If B's start value is smaller than A's start value then B comes
   * before A.
   *
   * If A and B have the same start value, the the end of the intervals
   * are checked and if A has a lower interval end than B, then A is
   * considered to come before B in that case.
   *
   * @note This operator does not perform any check about the other interval
   * being valid or not. It is up to the caller to verify that if needed, before
   * calling this member function.
   *
   * @param other the other interval.
   * @return true if this is smaller than the other
   * @return false if this is equal or greater than the other.
   */
  virtual bool operator<(const Gno_interval &other) const;
 
  /**
   * @brief This checks whether this interval intersects with the other.
   *
   * @note This operator does not perform any check about the other interval
   * being valid or not. It is up to the caller to verify that if needed, before
   * calling this member function.
   *
   * @param other The other interval to check against this one.
   * @return true if the intervals intersect.
   * @return false if it does not intersect.
   */
  virtual bool intersects(const Gno_interval &other) const;
 
  /**
   * @brief Checks if this interval is contiguous with the other one.
   *
   * Two intervals are contiguous if they do not intersect but there
   * are no gaps between them. No gaps means that the upper limit of
   * interval A is the value immediately preceding the lower limit
   * of interval B, under numeric natural ordering.
   *
   * @note This operator does not perform any check about the other interval
   * being valid or not. It is up to the caller to verify that if needed, before
   * calling this member function.
   *
   * @param other the interval to check against.
   * @return true if the intervals are contiguous.
   * @return false otherwise.
   */
  virtual bool contiguous(const Gno_interval &other) const;
 
  /**
   * @brief Checks if the other interval intersects or is contiguous with this
   * one.
   *
   * @param other The interval to check against this one.
   * @return true if the other interval intersects or is contiguous with this
   * one.
   * @return false otherwise.
   */
  virtual bool intersects_or_contiguous(const Gno_interval &other) const;
 
  /**
   * @brief Adds the other interval to this one.
   *
   * For this operation to complete successfully, the intervals must
   * intersect or be contiguous. Otherwise, the operation will fail.
   *
   * @note This operator does not perform any check about the other interval
   * being valid or not. It is up to the caller to verify that if needed, before
   * calling this member function.
   *
   * @param other The interval to add to this one.
   * @return true if the adding was not successful.
   * @return false if the adding was successful.
   */
  virtual bool add(const Gno_interval &other);
 
  /**
   * @brief Gets the first sequence number in the interval.
   *
   * @return the first sequence number of the interval.
   */
  virtual gno_t get_start() const;
 
  /**
   * @brief Gets the last sequence number in the interval.
   *
   * @return the last sequence number in the interval.
   */
  virtual gno_t get_end() const;
 
  /**
   * @brief Number of entries in this interval.
   *
   * @return the size of the interval.
   */
  virtual std::size_t count() const;
 
  /**
   * @brief Gets a human readable representation of this identifier.
   *
   * @return A human readable representation of this identifier.
   */
  virtual std::string to_string() const;
 
  /**
   * @brief Checks whether this interval is valid or not.
   *
   * An interval is invalid if the start value is smaller than 0 or
   * if the start is larger than the end of the interval.
   *
   * @return true if the interval is valid, false otherwise.
   */
  virtual bool is_valid() const;
};
 
/**
 * @brief This class represents a set of transaction identifiers.
 *
 * A set of transaction identifiers contains zero or more entries. When there
 * are multiple entries, there can multiple intervals as well. Different
 * intervals may share the same UUID part or not. This class abstracts that
 * in-memory representation.
 *
 */
class Gtid_set {
 public:
  static const inline std::string empty_gtid_set_str{""};
  /// In 'UUID:INTERVAL:INTERVAL', this is the second ':'
  static const inline std::string separator_interval{":"};
  /// In 'SID:GNO,SID:GNO', this is the ','
  static const inline std::string separator_uuid_set{","};
  using Tag = mysql::gtid::Tag;
  using Tsid = mysql::gtid::Tsid;
 
 protected:
  [[NODISCARD]] virtual bool do_add(const Tsid &tsid,
                                    const Gno_interval &interval);
  [[NODISCARD]] virtual bool do_add(const Uuid &uuid, const Tag &tag,
                                    const Gno_interval &interval);
 
 public:
  /**
   * @brief Tsid_interval_map is a 2-level map between tsids and an ordered
   * set of Gno_intervals.
   * Uuid is mapped into GTID tags, each pair of Uuid and Tag (TSID) is mapped
   * into ordered set of gno intervals
   */
  using Interval_set = std::set<Gno_interval>;
  using Tag_interval_map = std::map<Tag, Interval_set>;
  using Tsid_interval_map = std::map<Uuid, Tag_interval_map>;
 
  Gtid_set() = default;
  virtual ~Gtid_set();
 
  Gtid_set(const Gtid_set &other) = delete;
 
  /**
   * @brief Copy assignment.
   *
   * @note This operator does not check whether the parameters are valid
   * or not. The caller should perform such check before calling this member
   * function.
   *
   * @param other the Gtid_set to be copied over to this one.
   * @return Gtid_set& a reference to the copied Gtid_set.
   */
  Gtid_set &operator=(const Gtid_set &other);
 
  /**
   * @brief Compares this set with another one.
   *
   * @param other The other set to compare this one with.
   * @return true If both sets match.
   * @return false If sets do not match.
   */
  virtual bool operator==(const Gtid_set &other) const;
 
  /**
   * @brief Iterates through recorded TSIDs and returns
   * format of the Gtid_set
   *
   * @return Format of this GTID set
   * @see Gtid_format
   */
  virtual Gtid_format get_gtid_set_format() const;
 
  /**
   * @brief Adds a new interval indexed by the given uuid.
   *
   * @note This member function does not check whether the parameters are valid
   * or not. The caller should perform such check before calling this member
   * function.
   *
   * @return true if the there was an error adding the interval, false
   * otherwise.
   */
  [[NODISCARD]] virtual bool add(const Tsid &tsid,
                                 const Gno_interval &interval);
 
  /**
   * @brief Gets a copy of the internal set.
   *
   * @return an internal copy of the given set.
   */
  virtual const Tsid_interval_map &get_gtid_set() const;
 
  /**
   * @brief Add a set of identifiers to this one.
   *
   * @note This member function does not check whether the parameters are valid
   * or not. The caller should perform such check before calling this member
   * function.
   *
   * @param other the set to add to this one.
   * @return true if there was a failure adding the gtids.
   * @return false otherwise.
   */
  virtual bool add(const Gtid_set &other);
 
  /**
   * @brief Get the num TSIDs held in the GTID set
   *
   * @return std::size_t Number of TSIDs
   */
  virtual std::size_t get_num_tsids() const;
 
  /**
   * @brief Adds the given identifier to this set.
   *
   * @note This member function does not check whether the parameters are valid
   * or not. The caller should perform such check before calling this member
   * function.
   *
   * @param gtid the identifier to add.
   * @return true if it failed while adding the identifier.
   * @return false otherwise.
   */
  virtual bool add(const Gtid &gtid);
 
  /**
   * @brief Checks whether this set contains the given identifier.
   *
   * @note This member function does not check whether the parameters are valid
   * or not. The caller should perform such check before calling this member
   * function.
   *
   * @param gtid the gtid to check whehther it exists in this set or not.
   * @return true if the identifier exists in this set.
   * @return false if the identifier does not exist in this set.
   */
  virtual bool contains(const Gtid &gtid) const;
 
  /**
   * @brief A human readable representation of this set.
   *
   * @return a human readable representation of this set.
   */
  virtual std::string to_string() const;
 
  /**
   * @brief Resets this set, making it empty.
   *
   */
  virtual void reset();
 
  /**
   * @brief Returns true if this is an empty set.
   *
   * @return true
   * @return false
   */
  virtual bool is_empty() const;
 
  /**
   * @brief Gets the number of entries in this set.
   *
   * @return the cardinality of this set.
   */
  virtual std::size_t count() const;
 
 protected:
  /**
   * @brief An ordered map of entries mapping Uuid to a list of intervals.
   */
  Tsid_interval_map m_gtid_set{};
};
 
}  // namespace mysql::gtid
 
/// @}
 
#endif  // MYSQL_GTID_GTIDSET_H