ha_mock.h

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/* Copyright (c) 2018, 2025, Oracle and/or its affiliates.
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.
 
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   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
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   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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   You should have received a copy of the GNU General Public License
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   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
 
#ifndef PLUGIN_SECONDARY_ENGINE_MOCK_HA_MOCK_H_
#define PLUGIN_SECONDARY_ENGINE_MOCK_HA_MOCK_H_
 
#include "my_base.h"
#include "sql/handler.h"
#include "thr_lock.h"
 
class THD;
struct TABLE;
struct TABLE_SHARE;
 
namespace dd {
class Table;
}
 
namespace mock {
 
/**
 * The MOCK storage engine is used for testing MySQL server functionality
 * related to secondary storage engines.
 *
 * There are currently no secondary storage engines mature enough to be merged
 * into mysql-trunk. Therefore, this bare-minimum storage engine, with no
 * actual functionality and implementing only the absolutely necessary handler
 * interfaces to allow setting it as a secondary engine of a table, was created
 * to facilitate pushing MySQL server code changes to mysql-trunk with test
 * coverage without depending on ongoing work of other storage engines.
 *
 * @note This mock storage engine does not support being set as a primary
 * storage engine.
 */
class ha_mock : public handler {
 public:
  ha_mock(handlerton *hton, TABLE_SHARE *table_share);
 
 private:
  int create(const char *, TABLE *, HA_CREATE_INFO *, dd::Table *) override {
    return HA_ERR_WRONG_COMMAND;
  }
 
  int open(const char *name, int mode, unsigned int test_if_locked,
           const dd::Table *table_def) override;
 
  int close() override { return 0; }
 
  int rnd_init(bool) override { return 0; }
 
  int rnd_next(unsigned char *) override { return HA_ERR_END_OF_FILE; }
 
  int rnd_pos(unsigned char *, unsigned char *) override {
    return HA_ERR_WRONG_COMMAND;
  }
 
  int info(unsigned int) override;
 
  ha_rows records_in_range(unsigned int index, key_range *min_key,
                           key_range *max_key) override;
 
  void position(const unsigned char *) override {}
 
  unsigned long index_flags(unsigned int, unsigned int, bool) const override;
 
  THR_LOCK_DATA **store_lock(THD *thd, THR_LOCK_DATA **to,
                             thr_lock_type lock_type) override;
 
  Table_flags table_flags() const override;
 
  const char *table_type() const override { return "MOCK"; }
 
  /**
   * Load table into the secondary engine.
   *
   * @param[in] table - table to be loaded
   * @param[out] skip_metadata_update - should the DD metadata be updated for
   * the load of this table
   * @return 0 if success
   */
  int load_table(const TABLE &table, bool *skip_metadata_update) override;
 
  /**
   * Unload the table from secondary engine
   *
   * @param[in] db_name     database name
   * @param[in] table_name  table name
   * @param[in] error_if_not_loaded - whether to report an error if the table is
   * already not present in the secondary engine.
   * @return 0 if success
   */
  int unload_table(const char *db_name, const char *table_name,
                   bool error_if_not_loaded) override;
 
  THR_LOCK_DATA m_lock;
};
 
}  // namespace mock
 
#endif  // PLUGIN_SECONDARY_ENGINE_MOCK_HA_MOCK_H_