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/** @file include/fts0types.h
 Full text search types file

 Created 2007-03-27 Sunny Bains
 *******************************************************/

#ifndef INNOBASE_FTS0TYPES_H
#define INNOBASE_FTS0TYPES_H

#include <cstdint>
#include "fts0fts.h"
#include "fut0fut.h"
#include "pars0pars.h"
#include "que0types.h"
#include "univ.i"
#include "ut0byte.h"
#include "ut0rbt.h"

/** Types used within FTS. */
struct fts_que_t;
struct fts_node_t;

/** Callbacks used within FTS. */
typedef pars_user_func_cb_t fts_sql_callback;
typedef void (*fts_filter)(void *, fts_node_t *, void *, ulint len);

/** Statistics relevant to a particular document, used during retrieval. */
struct fts_doc_stats_t {
  doc_id_t doc_id;  /*!< Document id */
  ulint word_count; /*!< Total words in the document */
};

/** It's main purpose is to store the SQL prepared statements that
are required to retrieve a document from the database. */
struct fts_get_doc_t {
  fts_index_cache_t *index_cache; /*!< The index cache instance */

  /*!< Parsed sql statement */
  que_t *get_document_graph;
  fts_cache_t *cache; /*!< The parent cache */
};

/** Since we can have multiple FTS indexes on a table, we keep a
per index cache of words etc. */
struct fts_index_cache_t {
  dict_index_t *index; /*!< The FTS index instance */

  ib_rbt_t *words; /*!< Nodes; indexed by fts_string_t*,
                   cells are fts_tokenizer_word_t*.*/

  ib_vector_t *doc_stats; /*!< Array of the fts_doc_stats_t
                          contained in the memory buffer.
                          Must be in sorted order (ascending).
                          The  ideal choice is an rb tree but
                          the rb tree imposes a space overhead
                          that we can do without */

  que_t **ins_graph; /*!< Insert query graphs */

  que_t **sel_graph;     /*!< Select query graphs */
  CHARSET_INFO *charset; /*!< charset */
};

/** For supporting the tracking of updates on multiple FTS indexes we need
to track which FTS indexes need to be updated. For INSERT and DELETE we
update all fts indexes. */
struct fts_update_t {
  doc_id_t doc_id; /*!< The doc id affected */

  ib_vector_t *fts_indexes; /*!< The FTS indexes that need to be
                            updated. A NULL value means all
                            indexes need to be updated.  This
                            vector is not allocated on the heap
                            and so must be freed explicitly,
                            when we are done with it */
};

/** Stop word control infotmation. */
struct fts_stopword_t {
  ulint status;              /*!< Status of the stopword tree */
  ib_alloc_t *heap;          /*!< The memory allocator to use */
  ib_rbt_t *cached_stopword; /*!< This stores all active stopwords */
  CHARSET_INFO *charset;     /*!< charset for stopword */
};

/** The SYNC state of the cache. There is one instance of this struct
associated with each ADD thread. */
struct fts_sync_t {
  trx_t *trx;           /*!< The transaction used for SYNCing
                        the cache to disk */
  dict_table_t *table;  /*!< Table with FTS index(es) */
  ulint max_cache_size; /*!< Max size in bytes of the cache */
  bool cache_full;      /*!< flag, when true it indicates that
                         we need to sync the cache to disk */
  ulint lower_index;    /*!< the start index of the doc id
                        vector from where to start adding
                        documents to the FTS cache */
  ulint upper_index;    /*!< max index of the doc id vector to
                        add to the FTS cache */
  bool interrupted;     /*!< true if SYNC was interrupted */
  doc_id_t min_doc_id;  /*!< The smallest doc id added to the
                        cache. It should equal to
                        doc_ids[lower_index] */
  doc_id_t max_doc_id;  /*!< The doc id at which the cache was
                        noted as being full, we use this to
                        set the upper_limit field */
  std::chrono::steady_clock::time_point start_time;
  /*!< SYNC start time */
  bool in_progress;  /*!< flag whether sync is in progress.*/
  bool unlock_cache; /*!< flag whether unlock cache when
                     write fts node */
  os_event_t event;  /*!< sync finish event */
};

/** The cache for the FTS system. It is a memory-based inverted index
that new entries are added to, until it grows over the configured maximum
size, at which time its contents are written to the INDEX table. */
struct fts_cache_t {
#ifndef UNIV_HOTBACKUP
  rw_lock_t lock; /*!< lock protecting all access to the
                  memory buffer. FIXME: this needs to
                  be our new upgrade-capable rw-lock */

  rw_lock_t init_lock; /*!< lock used for the cache
                       initialization, it has different
                       SYNC level as above cache lock */
#endif                 /* !UNIV_HOTBACKUP */

  ib_mutex_t optimize_lock; /*!< Lock for OPTIMIZE */

  ib_mutex_t deleted_lock; /*!< Lock covering deleted_doc_ids */

  ib_mutex_t doc_id_lock; /*!< Lock covering Doc ID */

  ib_vector_t *deleted_doc_ids; /*!< Array of deleted doc ids, each
                                element is of type fts_update_t */

  ib_vector_t *indexes; /*!< We store the stats and inverted
                        index for the individual FTS indexes
                        in this vector. Each element is
                        an instance of fts_index_cache_t */

  ib_vector_t *get_docs; /*!< information required to read
                         the document from the table. Each
                         element is of type fts_doc_t */

  ulint total_size;                /*!< total size consumed by the ilist
                                   field of all nodes. SYNC is run
                                   whenever this gets too big */
  uint64_t total_size_before_sync; /*!< total size of fts cache,
                                   when last SYNC request was sent */
  fts_sync_t *sync;                /*!< sync structure to sync data to
                                   disk */
  ib_alloc_t *sync_heap;           /*!< The heap allocator, for indexes
                                   and deleted_doc_ids, ie. transient
                                   objects, they are recreated after
                                   a SYNC is completed */

  ib_alloc_t *self_heap; /*!< This heap is the heap out of
                         which an instance of the cache itself
                         was created. Objects created using
                         this heap will last for the lifetime
                         of the cache */

  doc_id_t next_doc_id; /*!< Next doc id */

  doc_id_t synced_doc_id; /*!< Doc ID sync-ed to CONFIG table */

  doc_id_t first_doc_id; /*!< first doc id since this table
                         was opened */

  ulint deleted; /*!< Number of doc ids deleted since
                 last optimized. This variable is
                 covered by deleted_lock */

  ulint added; /*!< Number of doc ids added since last
               optimized. This variable is covered by
               the deleted lock */

  fts_stopword_t stopword_info; /*!< Cached stopwords for the FTS */
  mem_heap_t *cache_heap;       /*!< Cache Heap */
};

/** Columns of the FTS auxiliary INDEX table */
struct fts_node_t {
  doc_id_t first_doc_id; /*!< First document id in ilist. */

  doc_id_t last_doc_id; /*!< Last document id in ilist. */

  byte *ilist; /*!< Binary list of documents & word
               positions the token appears in.
               TODO: For now, these are simply
               ut_malloc'd, but if testing shows
               that they waste memory unacceptably, a
               special memory allocator will have
               to be written */

  ulint doc_count; /*!< Number of doc ids in ilist */

  ulint ilist_size; /*!< Used size of ilist in bytes. */

  ulint ilist_size_alloc;
  /*!< Allocated size of ilist in
  bytes */
  bool synced; /*!< flag whether the node is synced */
};

/** A tokenizer word. Contains information about one word. */
struct fts_tokenizer_word_t {
  fts_string_t text; /*!< Token text. */

  ib_vector_t *nodes; /*!< Word node ilists, each element is
                      of type fts_node_t */
};

/** Word text plus it's array of nodes as on disk in FTS index */
struct fts_word_t {
  fts_string_t text;  /*!< Word value in UTF-8 */
  ib_vector_t *nodes; /*!< Nodes read from disk */

  ib_alloc_t *heap_alloc; /*!< For handling all allocations */
};

/** Callback for reading and filtering nodes that are read from FTS index */
struct fts_fetch_t {
  void *read_arg; /*!< Arg for the sql_callback */

  fts_sql_callback read_record; /*!< Callback for reading index
                                record */
  ulint total_memory;           /*!< Total memory used */
};

/** For horizontally splitting an FTS auxiliary index */
struct fts_index_selector_t {
  ulint value; /*!< Character value at which
               to split */

  const char *suffix; /*!< FTS aux index suffix */
};

/** This type represents a single document field.
 When fulltext index spans multiple columns, the
 entire document (all indexed text in a row)
 is comprised of multiple fields, one per indexed
 column. */
struct fts_doc_t {
  fts_string_t text; /*!< document text */

  bool found; /*!< true if the document was found
               successfully in the database */

  ib_rbt_t *tokens; /*!< This is filled when the document
                    is tokenized. Tokens; indexed by
                    fts_string_t*, cells are of type
                    fts_token_t* */

  ib_alloc_t *self_heap; /*!< An instance of this type is
                         allocated from this heap along
                         with any objects that have the
                         same lifespan, most notably
                         the vector of token positions */
  CHARSET_INFO *charset; /*!< Document's charset info */

  st_mysql_ftparser *parser; /*!< fts plugin parser */

  bool is_ngram; /*!< Whether it is a ngram parser */

  ib_rbt_t *stopwords; /*!< Stopwords */
};

/** A token and its positions within a document. */
struct fts_token_t {
  fts_string_t text; /*!< token text */

  ib_vector_t *positions; /*!< an array of the positions the
                          token is found in; each item is
                          actually an ulint. */
};

/** It's defined in fts/fts0fts.c */
extern const fts_index_selector_t fts_index_selector[];

/** It's defined in fts/fts0fts.c */
extern const fts_index_selector_t fts_index_selector_5_7[];

/** Decode and return the integer that was encoded using our VLC scheme.
@param[in,out]  ptr     ptr to decode from, this ptr is incremented
                        by the number of bytes decoded
@return value decoded */
inline uint64_t fts_decode_vlc(byte **ptr);

/** Duplicate a string.
@param[in]      dst     dup to here
@param[in]      src     src string
@param[in]      heap    heap to use
*/
inline void fts_string_dup(fts_string_t *dst, const fts_string_t *src,
                           mem_heap_t *heap);

/** Return length of val if it were encoded using our VLC scheme.
@param[in]     val      value to encode
@return length of value encoded, in bytes */
inline unsigned int fts_get_encoded_len(uint64_t val);

/** Encode an integer using our VLC scheme and return the length in bytes.
@param[in]      val     value to encode
@param[in]      buf     buffer, must have enough space
@return length of value encoded, in bytes */
inline unsigned int fts_encode_int(uint64_t val, byte *buf);

/** Get the selected FTS aux INDEX suffix. */
inline const char *fts_get_suffix(ulint selected); /*!< in: selected index */

/** Return the selected FTS aux index suffix in 5.7 compatible format
@param[in]      selected        selected index
@return the suffix name */
inline const char *fts_get_suffix_5_7(ulint selected);

/** Select the FTS auxiliary table for the given character.
@param[in]      cs      charset
@param[in]      str     string
@param[in]      len     string length in bytes
@retval the auxiliary table number to use for the string, zero-based */
inline ulint fts_select_index(const CHARSET_INFO *cs, const byte *str,
                              ulint len);

#include "fts0types.ic"
#include "fts0vlc.ic"

#endif /* INNOBASE_FTS0TYPES_H */