dependency_adapter.h

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//
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#ifndef MYSQL_CSA_DEPENDENCY_ADAPTER_H
#define MYSQL_CSA_DEPENDENCY_ADAPTER_H
 
#include <cstdint>
#include <memory>
#include <optional>
#include "mysql/scheduler/task_id.h"
 
namespace mysql::csa {
 
class Dependency_adapter;
/// @brief Unique pointer type for Dependency_adapter
using Dependency_adapter_ptr = std::unique_ptr<Dependency_adapter>;
 
/// @brief Class that resolves dependencies based on transaction sequence
/// number and last committed. It returns id of dependent task for a
/// dependency tracker in the scheduler
class Dependency_adapter {
 public:
  /// @brief Alias for task identifier from scheduler
  using Task_id = mysql::scheduler::Task_id;
  /// @brief Optional resolved task identifier
  using Task_id_resolved = std::optional<Task_id>;
  /// @brief Optional clock delay value
  using Clock_delay = std::optional<uint64_t>;
 
  /// @brief Virtual destructor
  virtual ~Dependency_adapter() = default;
 
  /// @brief Remember the worker pool size if needed. Default - unused
  virtual void set_worker_num(uint32_t) {}
 
  /// @brief Solves dependencies - figures out after which task a task with
  /// the given id should run
  /// @param id Task id
  /// @param seq_num Transaction sequence number
  /// @param commit_parent Transaction commit parent (LC)
  /// @return A pair containing an optional clock delay and an optional resolved
  /// task ID
  virtual std::pair<Clock_delay, Task_id_resolved> solve(
      Task_id id, int64_t seq_num, int64_t commit_parent) = 0;
};
 
}  // namespace mysql::csa
 
#endif  // MYSQL_CSA_DEPENDENCY_ADAPTER_H