/* Copyright (c) 2004, 2010, 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 as published by the Free Software Foundation; version 2 of the License. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */ /** @file ha_example.h @brief The ha_example engine is a stubbed storage engine for example purposes only; it does nothing at this point. Its purpose is to provide a source code illustration of how to begin writing new storage engines; see also /storage/example/ha_example.cc. @note Please read ha_example.cc before reading this file. Reminder: The example storage engine implements all methods that are *required* to be implemented. For a full list of all methods that you can implement, see handler.h. @see /sql/handler.h and /storage/example/ha_example.cc */ #ifdef USE_PRAGMA_INTERFACE #pragma interface /* gcc class implementation */ #endif #include "my_global.h" /* ulonglong */ #include "thr_lock.h" /* THR_LOCK, THR_LOCK_DATA */ #include "handler.h" /* handler */ #include "my_base.h" /* ha_rows */ /** @brief Example_share is a class that will be shared among all open handlers. This example implements the minimum of what you will probably need. */ class Example_share : public Handler_share { public: mysql_mutex_t mutex; THR_LOCK lock; Example_share(); ~Example_share() { thr_lock_delete(&lock); mysql_mutex_destroy(&mutex); } }; /** @brief Class definition for the storage engine */ class ha_example: public handler { THR_LOCK_DATA lock; ///< MySQL lock Example_share *share; ///< Shared lock info Example_share *get_share(); ///< Get the share public: ha_example(handlerton *hton, TABLE_SHARE *table_arg); ~ha_example() { } /** @brief The name of the index type that will be used for display. Don't implement this method unless you really have indexes. */ const char *index_type(uint inx) { return "HASH"; } /** @brief This is a list of flags that indicate what functionality the storage engine implements. The current table flags are documented in handler.h */ ulonglong table_flags() const { /* We are saying that this engine is just statement capable to have an engine that can only handle statement-based logging. This is used in testing. */ return HA_BINLOG_STMT_CAPABLE; } /** @brief This is a bitmap of flags that indicates how the storage engine implements indexes. The current index flags are documented in handler.h. If you do not implement indexes, just return zero here. @details part is the key part to check. First key part is 0. If all_parts is set, MySQL wants to know the flags for the combined index, up to and including 'part'. */ ulong index_flags(uint inx, uint part, bool all_parts) const { return 0; } /** @brief unireg.cc will call max_supported_record_length(), max_supported_keys(), max_supported_key_parts(), uint max_supported_key_length() to make sure that the storage engine can handle the data it is about to send. Return *real* limits of your storage engine here; MySQL will do min(your_limits, MySQL_limits) automatically. */ uint max_supported_record_length() const { return HA_MAX_REC_LENGTH; } /** @brief unireg.cc will call this to make sure that the storage engine can handle the data it is about to send. Return *real* limits of your storage engine here; MySQL will do min(your_limits, MySQL_limits) automatically. @details There is no need to implement ..._key_... methods if your engine doesn't support indexes. */ uint max_supported_keys() const { return 0; } /** @brief unireg.cc will call this to make sure that the storage engine can handle the data it is about to send. Return *real* limits of your storage engine here; MySQL will do min(your_limits, MySQL_limits) automatically. @details There is no need to implement ..._key_... methods if your engine doesn't support indexes. */ uint max_supported_key_parts() const { return 0; } /** @brief unireg.cc will call this to make sure that the storage engine can handle the data it is about to send. Return *real* limits of your storage engine here; MySQL will do min(your_limits, MySQL_limits) automatically. @details There is no need to implement ..._key_... methods if your engine doesn't support indexes. */ uint max_supported_key_length() const { return 0; } /** @brief Called in test_quick_select to determine if indexes should be used. */ virtual double scan_time() { return (double) (stats.records+stats.deleted) / 20.0+10; } /** @brief This method will never be called if you do not implement indexes. */ virtual double read_time(uint, uint, ha_rows rows) { return (double) rows / 20.0+1; } /* Everything below are methods that we implement in ha_example.cc. Most of these methods are not obligatory, skip them and MySQL will treat them as not implemented */ /** @brief We implement this in ha_example.cc; it's a required method. */ int open(const char *name, int mode, uint test_if_locked); // required /** @brief We implement this in ha_example.cc; it's a required method. */ int close(void); // required /** @brief We implement this in ha_example.cc. It's not an obligatory method; skip it and and MySQL will treat it as not implemented. */ int write_row(const uchar *buf); /** @brief We implement this in ha_example.cc. It's not an obligatory method; skip it and and MySQL will treat it as not implemented. */ int update_row(const uchar *old_data, const uchar *new_data); /** @brief We implement this in ha_example.cc. It's not an obligatory method; skip it and and MySQL will treat it as not implemented. */ int delete_row(const uchar *buf); /** @brief We implement this in ha_example.cc. It's not an obligatory method; skip it and and MySQL will treat it as not implemented. */ int index_read_map(uchar *buf, const uchar *key, key_part_map keypart_map, enum ha_rkey_function find_flag); /** @brief We implement this in ha_example.cc. It's not an obligatory method; skip it and and MySQL will treat it as not implemented. */ int index_next(uchar *buf); /** @brief We implement this in ha_example.cc. It's not an obligatory method; skip it and and MySQL will treat it as not implemented. */ int index_prev(uchar *buf); /** @brief We implement this in ha_example.cc. It's not an obligatory method; skip it and and MySQL will treat it as not implemented. */ int index_first(uchar *buf); /** @brief We implement this in ha_example.cc. It's not an obligatory method; skip it and and MySQL will treat it as not implemented. */ int index_last(uchar *buf); /** @brief Unlike index_init(), rnd_init() can be called two consecutive times without rnd_end() in between (it only makes sense if scan=1). In this case, the second call should prepare for the new table scan (e.g if rnd_init() allocates the cursor, the second call should position the cursor to the start of the table; no need to deallocate and allocate it again. This is a required method. */ int rnd_init(bool scan); //required int rnd_end(); int rnd_next(uchar *buf); ///< required int rnd_pos(uchar *buf, uchar *pos); ///< required void position(const uchar *record); ///< required int info(uint); ///< required int extra(enum ha_extra_function operation); int external_lock(THD *thd, int lock_type); ///< required int delete_all_rows(void); ha_rows records_in_range(uint inx, const key_range *min_key, const key_range *max_key, page_range *pages); int delete_table(const char *from); int create(const char *name, TABLE *form, HA_CREATE_INFO *create_info); ///< required enum_alter_inplace_result check_if_supported_inplace_alter(TABLE* altered_table, Alter_inplace_info* ha_alter_info); THR_LOCK_DATA **store_lock(THD *thd, THR_LOCK_DATA **to, enum thr_lock_type lock_type); ///< required };