1<?php
  2/**
  3 * WordPress database access abstraction class.
  4 *
  5 * Original code from {@link http://php.justinvincent.com Justin Vincent (justin@visunet.ie)}
  6 *
  7 * @package WordPress
  8 * @subpackage Database
  9 * @since 0.71
 10 */
 11
 12/**
 13 * @since 0.71
 14 */
 15define( 'EZSQL_VERSION', 'WP1.25' );
 16
 17/**
 18 * @since 0.71
 19 */
 20define( 'OBJECT', 'OBJECT' );
 21// phpcs:ignore Generic.NamingConventions.UpperCaseConstantName.ConstantNotUpperCase
 22define( 'object', 'OBJECT' ); // Back compat.
 23
 24/**
 25 * @since 2.5.0
 26 */
 27define( 'OBJECT_K', 'OBJECT_K' );
 28
 29/**
 30 * @since 0.71
 31 */
 32define( 'ARRAY_A', 'ARRAY_A' );
 33
 34/**
 35 * @since 0.71
 36 */
 37define( 'ARRAY_N', 'ARRAY_N' );
 38
 39/**
 40 * WordPress database access abstraction class.
 41 *
 42 * This class is used to interact with a database without needing to use raw SQL statements.
 43 * By default, WordPress uses this class to instantiate the global $wpdb object, providing
 44 * access to the WordPress database.
 45 *
 46 * It is possible to replace the global instance with your own by setting the $wpdb global variable
 47 * in wp-content/db.php file to your class. The wpdb class will still be included, so you can
 48 * extend it or simply use your own.
 49 *
 50 * @link https://developer.wordpress.org/reference/classes/wpdb/
 51 *
 52 * @since 0.71
 53 */
 54#[AllowDynamicProperties]
 55class wpdb {
 56
 57	/**
 58	 * Whether to show SQL/DB errors.
 59	 *
 60	 * Default is to show errors if both WP_DEBUG and WP_DEBUG_DISPLAY evaluate to true.
 61	 *
 62	 * @since 0.71
 63	 *
 64	 * @var bool
 65	 */
 66	public $show_errors = false;
 67
 68	/**
 69	 * Whether to suppress errors during the DB bootstrapping. Default false.
 70	 *
 71	 * @since 2.5.0
 72	 *
 73	 * @var bool
 74	 */
 75	public $suppress_errors = false;
 76
 77	/**
 78	 * The error encountered during the last query.
 79	 *
 80	 * @since 2.5.0
 81	 *
 82	 * @var string
 83	 */
 84	public $last_error = '';
 85
 86	/**
 87	 * The number of queries made.
 88	 *
 89	 * @since 1.2.0
 90	 *
 91	 * @var int
 92	 */
 93	public $num_queries = 0;
 94
 95	/**
 96	 * Count of rows returned by the last query.
 97	 *
 98	 * @since 0.71
 99	 *
100	 * @var int
101	 */
102	public $num_rows = 0;
103
104	/**
105	 * Count of rows affected by the last query.
106	 *
107	 * @since 0.71
108	 *
109	 * @var int
110	 */
111	public $rows_affected = 0;
112
113	/**
114	 * The ID generated for an AUTO_INCREMENT column by the last query (usually INSERT).
115	 *
116	 * @since 0.71
117	 *
118	 * @var int
119	 */
120	public $insert_id = 0;
121
122	/**
123	 * The last query made.
124	 *
125	 * @since 0.71
126	 *
127	 * @var string
128	 */
129	public $last_query;
130
131	/**
132	 * Results of the last query.
133	 *
134	 * @since 0.71
135	 *
136	 * @var stdClass[]|null
137	 */
138	public $last_result;
139
140	/**
141	 * Database query result.
142	 *
143	 * Possible values:
144	 *
145	 * - `mysqli_result` instance for successful SELECT, SHOW, DESCRIBE, or EXPLAIN queries
146	 * - `true` for other query types that were successful
147	 * - `null` if a query is yet to be made or if the result has since been flushed
148	 * - `false` if the query returned an error
149	 *
150	 * @since 0.71
151	 *
152	 * @var mysqli_result|bool|null
153	 */
154	protected $result;
155
156	/**
157	 * Cached column info, for confidence checking data before inserting.
158	 *
159	 * @since 4.2.0
160	 *
161	 * @var array
162	 */
163	protected $col_meta = array();
164
165	/**
166	 * Calculated character sets keyed by table name.
167	 *
168	 * @since 4.2.0
169	 *
170	 * @var string[]
171	 */
172	protected $table_charset = array();
173
174	/**
175	 * Whether text fields in the current query need to be confidence checked.
176	 *
177	 * @since 4.2.0
178	 *
179	 * @var bool
180	 */
181	protected $check_current_query = true;
182
183	/**
184	 * Flag to ensure we don't run into recursion problems when checking the collation.
185	 *
186	 * @since 4.2.0
187	 *
188	 * @see wpdb::check_safe_collation()
189	 * @var bool
190	 */
191	private $checking_collation = false;
192
193	/**
194	 * Saved info on the table column.
195	 *
196	 * @since 0.71
197	 *
198	 * @var array
199	 */
200	protected $col_info;
201
202	/**
203	 * Log of queries that were executed, for debugging purposes.
204	 *
205	 * @since 1.5.0
206	 * @since 2.5.0 The third element in each query log was added to record the calling functions.
207	 * @since 5.1.0 The fourth element in each query log was added to record the start time.
208	 * @since 5.3.0 The fifth element in each query log was added to record custom data.
209	 *
210	 * @var array[] {
211	 *     Array of arrays containing information about queries that were executed.
212	 *
213	 *     @type array ...$0 {
214	 *         Data for each query.
215	 *
216	 *         @type string $0 The query's SQL.
217	 *         @type float  $1 Total time spent on the query, in seconds.
218	 *         @type string $2 Comma-separated list of the calling functions.
219	 *         @type float  $3 Unix timestamp of the time at the start of the query.
220	 *         @type array  $4 Custom query data.
221	 *     }
222	 * }
223	 */
224	public $queries;
225
226	/**
227	 * The number of times to retry reconnecting before dying. Default 5.
228	 *
229	 * @since 3.9.0
230	 *
231	 * @see wpdb::check_connection()
232	 * @var int
233	 */
234	protected $reconnect_retries = 5;
235
236	/**
237	 * WordPress table prefix.
238	 *
239	 * You can set this to have multiple WordPress installations in a single database.
240	 *
241	 * @since 2.5.0
242	 *
243	 * @var string
244	 */
245	public $prefix = '';
246
247	/**
248	 * WordPress base table prefix.
249	 *
250	 * @since 3.0.0
251	 *
252	 * @var string
253	 */
254	public $base_prefix;
255
256	/**
257	 * Whether the database queries are ready to start executing.
258	 *
259	 * @since 2.3.2
260	 *
261	 * @var bool
262	 */
263	public $ready = false;
264
265	/**
266	 * Blog ID.
267	 *
268	 * @since 3.0.0
269	 *
270	 * @var int
271	 */
272	public $blogid = 0;
273
274	/**
275	 * Site ID.
276	 *
277	 * @since 3.0.0
278	 *
279	 * @var int
280	 */
281	public $siteid = 0;
282
283	/**
284	 * List of WordPress per-site tables.
285	 *
286	 * @since 2.5.0
287	 *
288	 * @see wpdb::tables()
289	 * @var string[]
290	 */
291	public $tables = array(
292		'posts',
293		'comments',
294		'links',
295		'options',
296		'postmeta',
297		'terms',
298		'term_taxonomy',
299		'term_relationships',
300		'termmeta',
301		'commentmeta',
302	);
303
304	/**
305	 * List of deprecated WordPress tables.
306	 *
307	 * 'categories', 'post2cat', and 'link2cat' were deprecated in 2.3.0, db version 5539.
308	 *
309	 * @since 2.9.0
310	 *
311	 * @see wpdb::tables()
312	 * @var string[]
313	 */
314	public $old_tables = array( 'categories', 'post2cat', 'link2cat' );
315
316	/**
317	 * List of WordPress global tables.
318	 *
319	 * @since 3.0.0
320	 *
321	 * @see wpdb::tables()
322	 * @var string[]
323	 */
324	public $global_tables = array( 'users', 'usermeta' );
325
326	/**
327	 * List of Multisite global tables.
328	 *
329	 * @since 3.0.0
330	 *
331	 * @see wpdb::tables()
332	 * @var string[]
333	 */
334	public $ms_global_tables = array(
335		'blogs',
336		'blogmeta',
337		'signups',
338		'site',
339		'sitemeta',
340		'registration_log',
341	);
342
343	/**
344	 * List of deprecated WordPress Multisite global tables.
345	 *
346	 * @since 6.1.0
347	 *
348	 * @see wpdb::tables()
349	 * @var string[]
350	 */
351	public $old_ms_global_tables = array( 'sitecategories' );
352
353	/**
354	 * WordPress Comments table.
355	 *
356	 * @since 1.5.0
357	 *
358	 * @var string
359	 */
360	public $comments;
361
362	/**
363	 * WordPress Comment Metadata table.
364	 *
365	 * @since 2.9.0
366	 *
367	 * @var string
368	 */
369	public $commentmeta;
370
371	/**
372	 * WordPress Links table.
373	 *
374	 * @since 1.5.0
375	 *
376	 * @var string
377	 */
378	public $links;
379
380	/**
381	 * WordPress Options table.
382	 *
383	 * @since 1.5.0
384	 *
385	 * @var string
386	 */
387	public $options;
388
389	/**
390	 * WordPress Post Metadata table.
391	 *
392	 * @since 1.5.0
393	 *
394	 * @var string
395	 */
396	public $postmeta;
397
398	/**
399	 * WordPress Posts table.
400	 *
401	 * @since 1.5.0
402	 *
403	 * @var string
404	 */
405	public $posts;
406
407	/**
408	 * WordPress Terms table.
409	 *
410	 * @since 2.3.0
411	 *
412	 * @var string
413	 */
414	public $terms;
415
416	/**
417	 * WordPress Term Relationships table.
418	 *
419	 * @since 2.3.0
420	 *
421	 * @var string
422	 */
423	public $term_relationships;
424
425	/**
426	 * WordPress Term Taxonomy table.
427	 *
428	 * @since 2.3.0
429	 *
430	 * @var string
431	 */
432	public $term_taxonomy;
433
434	/**
435	 * WordPress Term Meta table.
436	 *
437	 * @since 4.4.0
438	 *
439	 * @var string
440	 */
441	public $termmeta;
442
443	//
444	// Global and Multisite tables
445	//
446
447	/**
448	 * WordPress User Metadata table.
449	 *
450	 * @since 2.3.0
451	 *
452	 * @var string
453	 */
454	public $usermeta;
455
456	/**
457	 * WordPress Users table.
458	 *
459	 * @since 1.5.0
460	 *
461	 * @var string
462	 */
463	public $users;
464
465	/**
466	 * Multisite Blogs table.
467	 *
468	 * @since 3.0.0
469	 *
470	 * @var string|null
471	 */
472	public $blogs;
473
474	/**
475	 * Multisite Blog Metadata table.
476	 *
477	 * @since 5.1.0
478	 *
479	 * @var string|null
480	 */
481	public $blogmeta;
482
483	/**
484	 * Multisite Registration Log table.
485	 *
486	 * @since 3.0.0
487	 *
488	 * @var string|null
489	 */
490	public $registration_log;
491
492	/**
493	 * Multisite Signups table.
494	 *
495	 * @since 3.0.0
496	 *
497	 * @var string|null
498	 */
499	public $signups;
500
501	/**
502	 * Multisite Sites table.
503	 *
504	 * @since 3.0.0
505	 *
506	 * @var string|null
507	 */
508	public $site;
509
510	/**
511	 * Multisite Sitewide Terms table.
512	 *
513	 * @since 3.0.0
514	 *
515	 * @var string|null
516	 */
517	public $sitecategories;
518
519	/**
520	 * Multisite Site Metadata table.
521	 *
522	 * @since 3.0.0
523	 *
524	 * @var string|null
525	 */
526	public $sitemeta;
527
528	/**
529	 * Format specifiers for DB columns.
530	 *
531	 * Columns not listed here default to %s. Initialized during WP load.
532	 * Keys are column names, values are format types: 'ID' => '%d'.
533	 *
534	 * @since 2.8.0
535	 *
536	 * @see wpdb::prepare()
537	 * @see wpdb::insert()
538	 * @see wpdb::update()
539	 * @see wpdb::delete()
540	 * @see wp_set_wpdb_vars()
541	 * @var array
542	 */
543	public $field_types = array();
544
545	/**
546	 * Database table columns charset.
547	 *
548	 * @since 2.2.0
549	 *
550	 * @var string
551	 */
552	public $charset;
553
554	/**
555	 * Database table columns collate.
556	 *
557	 * @since 2.2.0
558	 *
559	 * @var string
560	 */
561	public $collate;
562
563	/**
564	 * Database Username.
565	 *
566	 * @since 2.9.0
567	 *
568	 * @var string
569	 */
570	protected $dbuser;
571
572	/**
573	 * Database Password.
574	 *
575	 * @since 3.1.0
576	 *
577	 * @var string
578	 */
579	protected $dbpassword;
580
581	/**
582	 * Database Name.
583	 *
584	 * @since 3.1.0
585	 *
586	 * @var string
587	 */
588	protected $dbname;
589
590	/**
591	 * Database Host.
592	 *
593	 * @since 3.1.0
594	 *
595	 * @var string
596	 */
597	protected $dbhost;
598
599	/**
600	 * Database handle.
601	 *
602	 * Possible values:
603	 *
604	 * - `mysqli` instance during normal operation
605	 * - `null` if the connection is yet to be made or has been closed
606	 * - `false` if the connection has failed
607	 *
608	 * @since 0.71
609	 *
610	 * @var mysqli|false|null
611	 */
612	protected $dbh;
613
614	/**
615	 * A textual description of the last query/get_row/get_var call.
616	 *
617	 * @since 3.0.0
618	 *
619	 * @var string
620	 */
621	public $func_call;
622
623	/**
624	 * Whether MySQL is used as the database engine.
625	 *
626	 * Set in wpdb::db_connect() to true, by default. This is used when checking
627	 * against the required MySQL version for WordPress. Normally, a replacement
628	 * database drop-in (db.php) will skip these checks, but setting this to true
629	 * will force the checks to occur.
630	 *
631	 * @since 3.3.0
632	 *
633	 * @var bool
634	 */
635	public $is_mysql = null;
636
637	/**
638	 * A list of incompatible SQL modes.
639	 *
640	 * @since 3.9.0
641	 *
642	 * @var string[]
643	 */
644	protected $incompatible_modes = array(
645		'NO_ZERO_DATE',
646		'ONLY_FULL_GROUP_BY',
647		'STRICT_TRANS_TABLES',
648		'STRICT_ALL_TABLES',
649		'TRADITIONAL',
650		'ANSI',
651	);
652
653	/**
654	 * Backward compatibility, where wpdb::prepare() has not quoted formatted/argnum placeholders.
655	 *
656	 * This is often used for table/field names (before %i was supported), and sometimes string formatting, e.g.
657	 *
658	 *     $wpdb->prepare( 'WHERE `%1$s` = "%2$s something %3$s" OR %1$s = "%4$-10s"', 'field_1', 'a', 'b', 'c' );
659	 *
660	 * But it's risky, e.g. forgetting to add quotes, resulting in SQL Injection vulnerabilities:
661	 *
662	 *     $wpdb->prepare( 'WHERE (id = %1s) OR (id = %2$s)', $_GET['id'], $_GET['id'] ); // ?id=id
663	 *
664	 * This feature is preserved while plugin authors update their code to use safer approaches:
665	 *
666	 *     $_GET['key'] = 'a`b';
667	 *
668	 *     $wpdb->prepare( 'WHERE %1s = %s',        $_GET['key'], $_GET['value'] ); // WHERE a`b = 'value'
669	 *     $wpdb->prepare( 'WHERE `%1$s` = "%2$s"', $_GET['key'], $_GET['value'] ); // WHERE `a`b` = "value"
670	 *
671	 *     $wpdb->prepare( 'WHERE %i = %s',         $_GET['key'], $_GET['value'] ); // WHERE `a``b` = 'value'
672	 *
673	 * While changing to false will be fine for queries not using formatted/argnum placeholders,
674	 * any remaining cases are most likely going to result in SQL errors (good, in a way):
675	 *
676	 *     $wpdb->prepare( 'WHERE %1$s = "%2$-10s"', 'my_field', 'my_value' );
677	 *     true  = WHERE my_field = "my_value  "
678	 *     false = WHERE 'my_field' = "'my_value  '"
679	 *
680	 * But there may be some queries that result in an SQL Injection vulnerability:
681	 *
682	 *     $wpdb->prepare( 'WHERE id = %1$s', $_GET['id'] ); // ?id=id
683	 *
684	 * So there may need to be a `_doing_it_wrong()` phase, after we know everyone can use
685	 * identifier placeholders (%i), but before this feature is disabled or removed.
686	 *
687	 * @since 6.2.0
688	 * @var bool
689	 */
690	private $allow_unsafe_unquoted_parameters = true;
691
692	/**
693	 * Whether to use the mysqli extension over mysql. This is no longer used as the mysql
694	 * extension is no longer supported.
695	 *
696	 * Default true.
697	 *
698	 * @since 3.9.0
699	 * @since 6.4.0 This property was removed.
700	 * @since 6.4.1 This property was reinstated and its default value was changed to true.
701	 *              The property is no longer used in core but may be accessed externally.
702	 *
703	 * @var bool
704	 */
705	private $use_mysqli = true;
706
707	/**
708	 * Whether we've managed to successfully connect at some point.
709	 *
710	 * @since 3.9.0
711	 *
712	 * @var bool
713	 */
714	private $has_connected = false;
715
716	/**
717	 * Time when the last query was performed.
718	 *
719	 * Only set when `SAVEQUERIES` is defined and truthy.
720	 *
721	 * @since 1.5.0
722	 *
723	 * @var float
724	 */
725	public $time_start = null;
726
727	/**
728	 * The last SQL error that was encountered.
729	 *
730	 * @since 2.5.0
731	 *
732	 * @var WP_Error|string
733	 */
734	public $error = null;
735
736	/**
737	 * Connects to the database server and selects a database.
738	 *
739	 * Does the actual setting up
740	 * of the class properties and connection to the database.
741	 *
742	 * @since 2.0.8
743	 *
744	 * @link https://core.trac.wordpress.org/ticket/3354
745	 *
746	 * @param string $dbuser     Database user.
747	 * @param string $dbpassword Database password.
748	 * @param string $dbname     Database name.
749	 * @param string $dbhost     Database host.
750	 */
751	public function __construct(
752		$dbuser,
753		#[\SensitiveParameter]
754		$dbpassword,
755		$dbname,
756		$dbhost
757	) {
758		if ( WP_DEBUG && WP_DEBUG_DISPLAY ) {
759			$this->show_errors();
760		}
761
762		$this->dbuser     = $dbuser;
763		$this->dbpassword = $dbpassword;
764		$this->dbname     = $dbname;
765		$this->dbhost     = $dbhost;
766
767		// wp-config.php creation will manually connect when ready.
768		if ( defined( 'WP_SETUP_CONFIG' ) ) {
769			return;
770		}
771
772		$this->db_connect();
773	}
774
775	/**
776	 * Makes private properties readable for backward compatibility.
777	 *
778	 * @since 3.5.0
779	 *
780	 * @param string $name The private member to get, and optionally process.
781	 * @return mixed The private member.
782	 */
783	public function __get( $name ) {
784		if ( 'col_info' === $name ) {
785			$this->load_col_info();
786		}
787
788		return $this->$name;
789	}
790
791	/**
792	 * Makes private properties settable for backward compatibility.
793	 *
794	 * @since 3.5.0
795	 *
796	 * @param string $name  The private member to set.
797	 * @param mixed  $value The value to set.
798	 */
799	public function __set( $name, $value ) {
800		$protected_members = array(
801			'col_meta',
802			'table_charset',
803			'check_current_query',
804			'allow_unsafe_unquoted_parameters',
805		);
806		if ( in_array( $name, $protected_members, true ) ) {
807			return;
808		}
809		$this->$name = $value;
810	}
811
812	/**
813	 * Makes private properties check-able for backward compatibility.
814	 *
815	 * @since 3.5.0
816	 *
817	 * @param string $name The private member to check.
818	 * @return bool If the member is set or not.
819	 */
820	public function __isset( $name ) {
821		return isset( $this->$name );
822	}
823
824	/**
825	 * Makes private properties un-settable for backward compatibility.
826	 *
827	 * @since 3.5.0
828	 *
829	 * @param string $name The private member to unset.
830	 */
831	public function __unset( $name ) {
832		unset( $this->$name );
833	}
834
835	/**
836	 * Sets $this->charset and $this->collate.
837	 *
838	 * @since 3.1.0
839	 */
840	public function init_charset() {
841		$charset = '';
842		$collate = '';
843
844		if ( function_exists( 'is_multisite' ) && is_multisite() ) {
845			$charset = 'utf8';
846			if ( defined( 'DB_COLLATE' ) && DB_COLLATE ) {
847				$collate = DB_COLLATE;
848			} else {
849				$collate = 'utf8_general_ci';
850			}
851		} elseif ( defined( 'DB_COLLATE' ) ) {
852			$collate = DB_COLLATE;
853		}
854
855		if ( defined( 'DB_CHARSET' ) ) {
856			$charset = DB_CHARSET;
857		}
858
859		$charset_collate = $this->determine_charset( $charset, $collate );
860
861		$this->charset = $charset_collate['charset'];
862		$this->collate = $charset_collate['collate'];
863	}
864
865	/**
866	 * Determines the best charset and collation to use given a charset and collation.
867	 *
868	 * For example, when able, utf8mb4 should be used instead of utf8.
869	 *
870	 * @since 4.6.0
871	 *
872	 * @param string $charset The character set to check.
873	 * @param string $collate The collation to check.
874	 * @return array {
875	 *     The most appropriate character set and collation to use.
876	 *
877	 *     @type string $charset Character set.
878	 *     @type string $collate Collation.
879	 * }
880	 */
881	public function determine_charset( $charset, $collate ) {
882		if ( ( ! ( $this->dbh instanceof mysqli ) ) || empty( $this->dbh ) ) {
883			return compact( 'charset', 'collate' );
884		}
885
886		if ( 'utf8' === $charset ) {
887			$charset = 'utf8mb4';
888		}
889
890		if ( 'utf8mb4' === $charset ) {
891			// _general_ is outdated, so we can upgrade it to _unicode_, instead.
892			if ( ! $collate || 'utf8_general_ci' === $collate ) {
893				$collate = 'utf8mb4_unicode_ci';
894			} else {
895				$collate = str_replace( 'utf8_', 'utf8mb4_', $collate );
896			}
897		}
898
899		// _unicode_520_ is a better collation, we should use that when it's available.
900		if ( $this->has_cap( 'utf8mb4_520' ) && 'utf8mb4_unicode_ci' === $collate ) {
901			$collate = 'utf8mb4_unicode_520_ci';
902		}
903
904		return compact( 'charset', 'collate' );
905	}
906
907	/**
908	 * Sets the connection's character set.
909	 *
910	 * @since 3.1.0
911	 *
912	 * @param mysqli $dbh     The connection returned by `mysqli_connect()`.
913	 * @param string $charset Optional. The character set. Default null.
914	 * @param string $collate Optional. The collation. Default null.
915	 */
916	public function set_charset( $dbh, $charset = null, $collate = null ) {
917		if ( ! isset( $charset ) ) {
918			$charset = $this->charset;
919		}
920		if ( ! isset( $collate ) ) {
921			$collate = $this->collate;
922		}
923		if ( $this->has_cap( 'collation' ) && ! empty( $charset ) ) {
924			$set_charset_succeeded = true;
925
926			if ( function_exists( 'mysqli_set_charset' ) && $this->has_cap( 'set_charset' ) ) {
927				$set_charset_succeeded = mysqli_set_charset( $dbh, $charset );
928			}
929
930			if ( $set_charset_succeeded ) {
931				$query = $this->prepare( 'SET NAMES %s', $charset );
932				if ( ! empty( $collate ) ) {
933					$query .= $this->prepare( ' COLLATE %s', $collate );
934				}
935				mysqli_query( $dbh, $query );
936			}
937		}
938	}
939
940	/**
941	 * Changes the current SQL mode, and ensures its WordPress compatibility.
942	 *
943	 * If no modes are passed, it will ensure the current SQL server modes are compatible.
944	 *
945	 * @since 3.9.0
946	 *
947	 * @param array $modes Optional. A list of SQL modes to set. Default empty array.
948	 */
949	public function set_sql_mode( $modes = array() ) {
950		if ( empty( $modes ) ) {
951			$res = mysqli_query( $this->dbh, 'SELECT @@SESSION.sql_mode' );
952
953			if ( empty( $res ) ) {
954				return;
955			}
956
957			$modes_array = mysqli_fetch_array( $res );
958
959			if ( empty( $modes_array[0] ) ) {
960				return;
961			}
962
963			$modes_str = $modes_array[0];
964
965			if ( empty( $modes_str ) ) {
966				return;
967			}
968
969			$modes = explode( ',', $modes_str );
970		}
971
972		$modes = array_change_key_case( $modes, CASE_UPPER );
973
974		/**
975		 * Filters the list of incompatible SQL modes to exclude.
976		 *
977		 * @since 3.9.0
978		 *
979		 * @param array $incompatible_modes An array of incompatible modes.
980		 */
981		$incompatible_modes = (array) apply_filters( 'incompatible_sql_modes', $this->incompatible_modes );
982
983		foreach ( $modes as $i => $mode ) {
984			if ( in_array( $mode, $incompatible_modes, true ) ) {
985				unset( $modes[ $i ] );
986			}
987		}
988
989		$modes_str = implode( ',', $modes );
990
991		mysqli_query( $this->dbh, "SET SESSION sql_mode='$modes_str'" );
992	}
993
994	/**
995	 * Sets the table prefix for the WordPress tables.
996	 *
997	 * @since 2.5.0
998	 *
999	 * @param string $prefix          Alphanumeric name for the new prefix.
1000	 * @param bool   $set_table_names Optional. Whether the table names, e.g. wpdb::$posts,
1001	 *                                should be updated or not. Default true.
1002	 * @return string|WP_Error Old prefix or WP_Error on error.
1003	 */
1004	public function set_prefix( $prefix, $set_table_names = true ) {
1005
1006		if ( preg_match( '|[^a-z0-9_]|i', $prefix ) ) {
1007			return new WP_Error( 'invalid_db_prefix', 'Invalid database prefix' );
1008		}
1009
1010		$old_prefix = is_multisite() ? '' : $prefix;
1011
1012		if ( isset( $this->base_prefix ) ) {
1013			$old_prefix = $this->base_prefix;
1014		}
1015
1016		$this->base_prefix = $prefix;
1017
1018		if ( $set_table_names ) {
1019			foreach ( $this->tables( 'global' ) as $table => $prefixed_table ) {
1020				$this->$table = $prefixed_table;
1021			}
1022
1023			if ( is_multisite() && empty( $this->blogid ) ) {
1024				return $old_prefix;
1025			}
1026
1027			$this->prefix = $this->get_blog_prefix();
1028
1029			foreach ( $this->tables( 'blog' ) as $table => $prefixed_table ) {
1030				$this->$table = $prefixed_table;
1031			}
1032
1033			foreach ( $this->tables( 'old' ) as $table => $prefixed_table ) {
1034				$this->$table = $prefixed_table;
1035			}
1036		}
1037		return $old_prefix;
1038	}
1039
1040	/**
1041	 * Sets blog ID.
1042	 *
1043	 * @since 3.0.0
1044	 *
1045	 * @param int $blog_id
1046	 * @param int $network_id Optional. Network ID. Default 0.
1047	 * @return int Previous blog ID.
1048	 */
1049	public function set_blog_id( $blog_id, $network_id = 0 ) {
1050		if ( ! empty( $network_id ) ) {
1051			$this->siteid = $network_id;
1052		}
1053
1054		$old_blog_id  = $this->blogid;
1055		$this->blogid = $blog_id;
1056
1057		$this->prefix = $this->get_blog_prefix();
1058
1059		foreach ( $this->tables( 'blog' ) as $table => $prefixed_table ) {
1060			$this->$table = $prefixed_table;
1061		}
1062
1063		foreach ( $this->tables( 'old' ) as $table => $prefixed_table ) {
1064			$this->$table = $prefixed_table;
1065		}
1066
1067		return $old_blog_id;
1068	}
1069
1070	/**
1071	 * Gets blog prefix.
1072	 *
1073	 * @since 3.0.0
1074	 *
1075	 * @param int $blog_id Optional. Blog ID to retrieve the table prefix for.
1076	 *                     Defaults to the current blog ID.
1077	 * @return string Blog prefix.
1078	 */
1079	public function get_blog_prefix( $blog_id = null ) {
1080		if ( is_multisite() ) {
1081			if ( null === $blog_id ) {
1082				$blog_id = $this->blogid;
1083			}
1084
1085			$blog_id = (int) $blog_id;
1086
1087			if ( defined( 'MULTISITE' ) && ( 0 === $blog_id || 1 === $blog_id ) ) {
1088				return $this->base_prefix;
1089			} else {
1090				return $this->base_prefix . $blog_id . '_';
1091			}
1092		} else {
1093			return $this->base_prefix;
1094		}
1095	}
1096
1097	/**
1098	 * Returns an array of WordPress tables.
1099	 *
1100	 * Also allows for the `CUSTOM_USER_TABLE` and `CUSTOM_USER_META_TABLE` to override the WordPress users
1101	 * and usermeta tables that would otherwise be determined by the prefix.
1102	 *
1103	 * The `$scope` argument can take one of the following:
1104	 *
1105	 * - 'all' - returns 'all' and 'global' tables. No old tables are returned.
1106	 * - 'blog' - returns the blog-level tables for the queried blog.
1107	 * - 'global' - returns the global tables for the installation, returning multisite tables only on multisite.
1108	 * - 'ms_global' - returns the multisite global tables, regardless if current installation is multisite.
1109	 * - 'old' - returns tables which are deprecated.
1110	 *
1111	 * @since 3.0.0
1112	 * @since 6.1.0 `old` now includes deprecated multisite global tables only on multisite.
1113	 *
1114	 * @uses wpdb::$tables
1115	 * @uses wpdb::$old_tables
1116	 * @uses wpdb::$global_tables
1117	 * @uses wpdb::$ms_global_tables
1118	 * @uses wpdb::$old_ms_global_tables
1119	 *
1120	 * @param string $scope   Optional. Possible values include 'all', 'global', 'ms_global', 'blog',
1121	 *                        or 'old' tables. Default 'all'.
1122	 * @param bool   $prefix  Optional. Whether to include table prefixes. If blog prefix is requested,
1123	 *                        then the custom users and usermeta tables will be mapped. Default true.
1124	 * @param int    $blog_id Optional. The blog_id to prefix. Used only when prefix is requested.
1125	 *                        Defaults to `wpdb::$blogid`.
1126	 * @return string[] Table names. When a prefix is requested, the key is the unprefixed table name.
1127	 */
1128	public function tables( $scope = 'all', $prefix = true, $blog_id = 0 ) {
1129		switch ( $scope ) {
1130			case 'all':
1131				$tables = array_merge( $this->global_tables, $this->tables );
1132				if ( is_multisite() ) {
1133					$tables = array_merge( $tables, $this->ms_global_tables );
1134				}
1135				break;
1136			case 'blog':
1137				$tables = $this->tables;
1138				break;
1139			case 'global':
1140				$tables = $this->global_tables;
1141				if ( is_multisite() ) {
1142					$tables = array_merge( $tables, $this->ms_global_tables );
1143				}
1144				break;
1145			case 'ms_global':
1146				$tables = $this->ms_global_tables;
1147				break;
1148			case 'old':
1149				$tables = $this->old_tables;
1150				if ( is_multisite() ) {
1151					$tables = array_merge( $tables, $this->old_ms_global_tables );
1152				}
1153				break;
1154			default:
1155				return array();
1156		}
1157
1158		if ( $prefix ) {
1159			if ( ! $blog_id ) {
1160				$blog_id = $this->blogid;
1161			}
1162			$blog_prefix   = $this->get_blog_prefix( $blog_id );
1163			$base_prefix   = $this->base_prefix;
1164			$global_tables = array_merge( $this->global_tables, $this->ms_global_tables );
1165			foreach ( $tables as $k => $table ) {
1166				if ( in_array( $table, $global_tables, true ) ) {
1167					$tables[ $table ] = $base_prefix . $table;
1168				} else {
1169					$tables[ $table ] = $blog_prefix . $table;
1170				}
1171				unset( $tables[ $k ] );
1172			}
1173
1174			if ( isset( $tables['users'] ) && defined( 'CUSTOM_USER_TABLE' ) ) {
1175				$tables['users'] = CUSTOM_USER_TABLE;
1176			}
1177
1178			if ( isset( $tables['usermeta'] ) && defined( 'CUSTOM_USER_META_TABLE' ) ) {
1179				$tables['usermeta'] = CUSTOM_USER_META_TABLE;
1180			}
1181		}
1182
1183		return $tables;
1184	}
1185
1186	/**
1187	 * Selects a database using the current or provided database connection.
1188	 *
1189	 * The database name will be changed based on the current database connection.
1190	 * On failure, the execution will bail and display a DB error.
1191	 *
1192	 * @since 0.71
1193	 *
1194	 * @param string $db  Database name.
1195	 * @param mysqli $dbh Optional. Database connection.
1196	 *                    Defaults to the current database handle.
1197	 */
1198	public function select( $db, $dbh = null ) {
1199		if ( is_null( $dbh ) ) {
1200			$dbh = $this->dbh;
1201		}
1202
1203		$success = mysqli_select_db( $dbh, $db );
1204
1205		if ( ! $success ) {
1206			$this->ready = false;
1207			if ( ! did_action( 'template_redirect' ) ) {
1208				wp_load_translations_early();
1209
1210				$message = '<h1>' . __( 'Cannot select database' ) . "</h1>\n";
1211
1212				$message .= '<p>' . sprintf(
1213					/* translators: %s: Database name. */
1214					__( 'The database server could be connected to (which means your username and password is okay) but the %s database could not be selected.' ),
1215					'<code>' . htmlspecialchars( $db, ENT_QUOTES ) . '</code>'
1216				) . "</p>\n";
1217
1218				$message .= "<ul>\n";
1219				$message .= '<li>' . __( 'Are you sure it exists?' ) . "</li>\n";
1220
1221				$message .= '<li>' . sprintf(
1222					/* translators: 1: Database user, 2: Database name. */
1223					__( 'Does the user %1$s have permission to use the %2$s database?' ),
1224					'<code>' . htmlspecialchars( $this->dbuser, ENT_QUOTES ) . '</code>',
1225					'<code>' . htmlspecialchars( $db, ENT_QUOTES ) . '</code>'
1226				) . "</li>\n";
1227
1228				$message .= '<li>' . sprintf(
1229					/* translators: %s: Database name. */
1230					__( 'On some systems the name of your database is prefixed with your username, so it would be like <code>username_%1$s</code>. Could that be the problem?' ),
1231					htmlspecialchars( $db, ENT_QUOTES )
1232				) . "</li>\n";
1233
1234				$message .= "</ul>\n";
1235
1236				$message .= '<p>' . sprintf(
1237					/* translators: %s: Support forums URL. */
1238					__( 'If you do not know how to set up a database you should <strong>contact your host</strong>. If all else fails you may find help at the <a href="%s">WordPress support forums</a>.' ),
1239					__( 'https://wordpress.org/support/forums/' )
1240				) . "</p>\n";
1241
1242				$this->bail( $message, 'db_select_fail' );
1243			}
1244		}
1245	}
1246
1247	/**
1248	 * Do not use, deprecated.
1249	 *
1250	 * Use esc_sql() or wpdb::prepare() instead.
1251	 *
1252	 * @since 2.8.0
1253	 * @deprecated 3.6.0 Use wpdb::prepare()
1254	 * @see wpdb::prepare()
1255	 * @see esc_sql()
1256	 *
1257	 * @param string $data
1258	 * @return string
1259	 */
1260	public function _weak_escape( $data ) {
1261		if ( func_num_args() === 1 && function_exists( '_deprecated_function' ) ) {
1262			_deprecated_function( __METHOD__, '3.6.0', 'wpdb::prepare() or esc_sql()' );
1263		}
1264		return addslashes( $data );
1265	}
1266
1267	/**
1268	 * Real escape using mysqli_real_escape_string().
1269	 *
1270	 * @since 2.8.0
1271	 *
1272	 * @see mysqli_real_escape_string()
1273	 *
1274	 * @param string $data String to escape.
1275	 * @return string Escaped string.
1276	 */
1277	public function _real_escape( $data ) {
1278		if ( ! is_scalar( $data ) ) {
1279			return '';
1280		}
1281
1282		if ( $this->dbh ) {
1283			$escaped = mysqli_real_escape_string( $this->dbh, $data );
1284		} else {
1285			$class = get_class( $this );
1286
1287			wp_load_translations_early();
1288			/* translators: %s: Database access abstraction class, usually wpdb or a class extending wpdb. */
1289			_doing_it_wrong( $class, sprintf( __( '%s must set a database connection for use with escaping.' ), $class ), '3.6.0' );
1290
1291			$escaped = addslashes( $data );
1292		}
1293
1294		return $this->add_placeholder_escape( $escaped );
1295	}
1296
1297	/**
1298	 * Escapes data. Works on arrays.
1299	 *
1300	 * @since 2.8.0
1301	 *
1302	 * @uses wpdb::_real_escape()
1303	 *
1304	 * @param string|array $data Data to escape.
1305	 * @return string|array Escaped data, in the same type as supplied.
1306	 */
1307	public function _escape( $data ) {
1308		if ( is_array( $data ) ) {
1309			foreach ( $data as $k => $v ) {
1310				if ( is_array( $v ) ) {
1311					$data[ $k ] = $this->_escape( $v );
1312				} else {
1313					$data[ $k ] = $this->_real_escape( $v );
1314				}
1315			}
1316		} else {
1317			$data = $this->_real_escape( $data );
1318		}
1319
1320		return $data;
1321	}
1322
1323	/**
1324	 * Do not use, deprecated.
1325	 *
1326	 * Use esc_sql() or wpdb::prepare() instead.
1327	 *
1328	 * @since 0.71
1329	 * @deprecated 3.6.0 Use wpdb::prepare()
1330	 * @see wpdb::prepare()
1331	 * @see esc_sql()
1332	 *
1333	 * @param string|array $data Data to escape.
1334	 * @return string|array Escaped data, in the same type as supplied.
1335	 */
1336	public function escape( $data ) {
1337		if ( func_num_args() === 1 && function_exists( '_deprecated_function' ) ) {
1338			_deprecated_function( __METHOD__, '3.6.0', 'wpdb::prepare() or esc_sql()' );
1339		}
1340		if ( is_array( $data ) ) {
1341			foreach ( $data as $k => $v ) {
1342				if ( is_array( $v ) ) {
1343					$data[ $k ] = $this->escape( $v, 'recursive' );
1344				} else {
1345					$data[ $k ] = $this->_weak_escape( $v, 'internal' );
1346				}
1347			}
1348		} else {
1349			$data = $this->_weak_escape( $data, 'internal' );
1350		}
1351
1352		return $data;
1353	}
1354
1355	/**
1356	 * Escapes content by reference for insertion into the database, for security.
1357	 *
1358	 * @uses wpdb::_real_escape()
1359	 *
1360	 * @since 2.3.0
1361	 *
1362	 * @param string $data String to escape.
1363	 */
1364	public function escape_by_ref( &$data ) {
1365		if ( ! is_float( $data ) ) {
1366			$data = $this->_real_escape( $data );
1367		}
1368	}
1369
1370	/**
1371	 * Quotes an identifier such as a table or field name.
1372	 *
1373	 * @since 6.2.0
1374	 *
1375	 * @param string $identifier Identifier to escape.
1376	 * @return string Escaped identifier.
1377	 */
1378	public function quote_identifier( $identifier ) {
1379		return '`' . $this->_escape_identifier_value( $identifier ) . '`';
1380	}
1381
1382	/**
1383	 * Escapes an identifier value without adding the surrounding quotes.
1384	 *
1385	 * - Permitted characters in quoted identifiers include the full Unicode
1386	 *   Basic Multilingual Plane (BMP), except U+0000.
1387	 * - To quote the identifier itself, you need to double the character, e.g. `a``b`.
1388	 *
1389	 * @since 6.2.0
1390	 *
1391	 * @link https://dev.mysql.com/doc/refman/8.0/en/identifiers.html
1392	 *
1393	 * @param string $identifier Identifier to escape.
1394	 * @return string Escaped identifier.
1395	 */
1396	private function _escape_identifier_value( $identifier ) {
1397		return str_replace( '`', '``', $identifier );
1398	}
1399
1400	/**
1401	 * Prepares a SQL query for safe execution.
1402	 *
1403	 * Uses `sprintf()`-like syntax. The following placeholders can be used in the query string:
1404	 *
1405	 * - `%d` (integer)
1406	 * - `%f` (float)
1407	 * - `%s` (string)
1408	 * - `%i` (identifier, e.g. table/field names)
1409	 *
1410	 * All placeholders MUST be left unquoted in the query string. A corresponding argument
1411	 * MUST be passed for each placeholder.
1412	 *
1413	 * Note: There is one exception to the above: for compatibility with old behavior,
1414	 * numbered or formatted string placeholders (eg, `%1$s`, `%5s`) will not have quotes
1415	 * added by this function, so should be passed with appropriate quotes around them.
1416	 *
1417	 * Literal percentage signs (`%`) in the query string must be written as `%%`. Percentage wildcards
1418	 * (for example, to use in LIKE syntax) must be passed via a substitution argument containing
1419	 * the complete LIKE string, these cannot be inserted directly in the query string.
1420	 * Also see wpdb::esc_like().
1421	 *
1422	 * Arguments may be passed as individual arguments to the method, or as a single array
1423	 * containing all arguments. A combination of the two is not supported.
1424	 *
1425	 * Examples:
1426	 *
1427	 *     $wpdb->prepare(
1428	 *         "SELECT * FROM `table` WHERE `column` = %s AND `field` = %d OR `other_field` LIKE %s",
1429	 *         array( 'foo', 1337, '%bar' )
1430	 *     );
1431	 *
1432	 *     $wpdb->prepare(
1433	 *         "SELECT DATE_FORMAT(`field`, '%%c') FROM `table` WHERE `column` = %s",
1434	 *         'foo'
1435	 *     );
1436	 *
1437	 *     $wpdb->prepare(
1438	 *         "SELECT * FROM %i WHERE %i = %s",
1439	 *         $table,
1440	 *         $field,
1441	 *         $value
1442	 *     );
1443	 *
1444	 * @since 2.3.0
1445	 * @since 5.3.0 Formalized the existing and already documented `...$args` parameter
1446	 *              by updating the function signature. The second parameter was changed
1447	 *              from `$args` to `...$args`.
1448	 * @since 6.2.0 Added `%i` for identifiers, e.g. table or field names.
1449	 *              Check support via `wpdb::has_cap( 'identifier_placeholders' )`.
1450	 *              This preserves compatibility with `sprintf()`, as the C version uses
1451	 *              `%d` and `$i` as a signed integer, whereas PHP only supports `%d`.
1452	 *
1453	 * @link https://www.php.net/sprintf Description of syntax.
1454	 *
1455	 * @param string      $query   Query statement with `sprintf()`-like placeholders.
1456	 * @param array|mixed $args    The array of variables to substitute into the query's placeholders
1457	 *                             if being called with an array of arguments, or the first variable
1458	 *                             to substitute into the query's placeholders if being called with
1459	 *                             individual arguments.
1460	 * @param mixed       ...$args Further variables to substitute into the query's placeholders
1461	 *                             if being called with individual arguments.
1462	 * @return string|void Sanitized query string, if there is a query to prepare.
1463	 */
1464	public function prepare( $query, ...$args ) {
1465		if ( is_null( $query ) ) {
1466			return;
1467		}
1468
1469		/*
1470		 * This is not meant to be foolproof -- but it will catch obviously incorrect usage.
1471		 *
1472		 * Note: str_contains() is not used here, as this file can be included
1473		 * directly outside of WordPress core, e.g. by HyperDB, in which case
1474		 * the polyfills from wp-includes/compat.php are not loaded.
1475		 */
1476		if ( false === strpos( $query, '%' ) ) {
1477			wp_load_translations_early();
1478			_doing_it_wrong(
1479				'wpdb::prepare',
1480				sprintf(
1481					/* translators: %s: wpdb::prepare() */
1482					__( 'The query argument of %s must have a placeholder.' ),
1483					'wpdb::prepare()'
1484				),
1485				'3.9.0'
1486			);
1487		}
1488
1489		/*
1490		 * Specify the formatting allowed in a placeholder. The following are allowed:
1491		 *
1492		 * - Sign specifier, e.g. $+d
1493		 * - Numbered placeholders, e.g. %1$s
1494		 * - Padding specifier, including custom padding characters, e.g. %05s, %'#5s
1495		 * - Alignment specifier, e.g. %05-s
1496		 * - Precision specifier, e.g. %.2f
1497		 */
1498		$allowed_format = '(?:[1-9][0-9]*[$])?[-+0-9]*(?: |0|\'.)?[-+0-9]*(?:\.[0-9]+)?';
1499
1500		/*
1501		 * If a %s placeholder already has quotes around it, removing the existing quotes
1502		 * and re-inserting them ensures the quotes are consistent.
1503		 *
1504		 * For backward compatibility, this is only applied to %s, and not to placeholders like %1$s,
1505		 * which are frequently used in the middle of longer strings, or as table name placeholders.
1506		 */
1507		$query = str_replace( "'%s'", '%s', $query ); // Strip any existing single quotes.
1508		$query = str_replace( '"%s"', '%s', $query ); // Strip any existing double quotes.
1509
1510		// Escape any unescaped percents (i.e. anything unrecognised).
1511		$query = preg_replace( "/%(?:%|$|(?!($allowed_format)?[sdfFi]))/", '%%\\1', $query );
1512
1513		// Extract placeholders from the query.
1514		$split_query = preg_split( "/(^|[^%]|(?:%%)+)(%(?:$allowed_format)?[sdfFi])/", $query, -1, PREG_SPLIT_DELIM_CAPTURE );
1515
1516		$split_query_count = count( $split_query );
1517
1518		/*
1519		 * Split always returns with 1 value before the first placeholder (even with $query = "%s"),
1520		 * then 3 additional values per placeholder.
1521		 */
1522		$placeholder_count = ( ( $split_query_count - 1 ) / 3 );
1523
1524		// If args were passed as an array, as in vsprintf(), move them up.
1525		$passed_as_array = ( isset( $args[0] ) && is_array( $args[0] ) && 1 === count( $args ) );
1526		if ( $passed_as_array ) {
1527			$args = $args[0];
1528		}
1529
1530		$new_query       = '';
1531		$key             = 2; // Keys 0 and 1 in $split_query contain values before the first placeholder.
1532		$arg_id          = 0;
1533		$arg_identifiers = array();
1534		$arg_strings     = array();
1535
1536		while ( $key < $split_query_count ) {
1537			$placeholder = $split_query[ $key ];
1538
1539			$format = substr( $placeholder, 1, -1 );
1540			$type   = substr( $placeholder, -1 );
1541
1542			if ( 'f' === $type && true === $this->allow_unsafe_unquoted_parameters
1543				/*
1544				 * Note: str_ends_with() is not used here, as this file can be included
1545				 * directly outside of WordPress core, e.g. by HyperDB, in which case
1546				 * the polyfills from wp-includes/compat.php are not loaded.
1547				 */
1548				&& '%' === substr( $split_query[ $key - 1 ], -1, 1 )
1549			) {
1550
1551				/*
1552				 * Before WP 6.2 the "force floats to be locale-unaware" RegEx didn't
1553				 * convert "%%%f" to "%%%F" (note the uppercase F).
1554				 * This was because it didn't check to see if the leading "%" was escaped.
1555				 * And because the "Escape any unescaped percents" RegEx used "[sdF]" in its
1556				 * negative lookahead assertion, when there was an odd number of "%", it added
1557				 * an extra "%", to give the fully escaped "%%%%f" (not a placeholder).
1558				 */
1559
1560				$s = $split_query[ $key - 2 ] . $split_query[ $key - 1 ];
1561				$k = 1;
1562				$l = strlen( $s );
1563				while ( $k <= $l && '%' === $s[ $l - $k ] ) {
1564					++$k;
1565				}
1566
1567				$placeholder = '%' . ( $k % 2 ? '%' : '' ) . $format . $type;
1568
1569				--$placeholder_count;
1570
1571			} else {
1572
1573				// Force floats to be locale-unaware.
1574				if ( 'f' === $type ) {
1575					$type        = 'F';
1576					$placeholder = '%' . $format . $type;
1577				}
1578
1579				if ( 'i' === $type ) {
1580					$placeholder = '`%' . $format . 's`';
1581					// Using a simple strpos() due to previous checking (e.g. $allowed_format).
1582					$argnum_pos = strpos( $format, '$' );
1583
1584					if ( false !== $argnum_pos ) {
1585						// sprintf() argnum starts at 1, $arg_id from 0.
1586						$arg_identifiers[] = ( ( (int) substr( $format, 0, $argnum_pos ) ) - 1 );
1587					} else {
1588						$arg_identifiers[] = $arg_id;
1589					}
1590				} elseif ( 'd' !== $type && 'F' !== $type ) {
1591					/*
1592					 * i.e. ( 's' === $type ), where 'd' and 'F' keeps $placeholder unchanged,
1593					 * and we ensure string escaping is used as a safe default (e.g. even if 'x').
1594					 */
1595					$argnum_pos = strpos( $format, '$' );
1596
1597					if ( false !== $argnum_pos ) {
1598						$arg_strings[] = ( ( (int) substr( $format, 0, $argnum_pos ) ) - 1 );
1599					} else {
1600						$arg_strings[] = $arg_id;
1601					}
1602
1603					/*
1604					 * Unquoted strings for backward compatibility (dangerous).
1605					 * First, "numbered or formatted string placeholders (eg, %1$s, %5s)".
1606					 * Second, if "%s" has a "%" before it, even if it's unrelated (e.g. "LIKE '%%%s%%'").
1607					 */
1608					if ( true !== $this->allow_unsafe_unquoted_parameters
1609						/*
1610						 * Note: str_ends_with() is not used here, as this file can be included
1611						 * directly outside of WordPress core, e.g. by HyperDB, in which case
1612						 * the polyfills from wp-includes/compat.php are not loaded.
1613						 */
1614						|| ( '' === $format && '%' !== substr( $split_query[ $key - 1 ], -1, 1 ) )
1615					) {
1616						$placeholder = "'%" . $format . "s'";
1617					}
1618				}
1619			}
1620
1621			// Glue (-2), any leading characters (-1), then the new $placeholder.
1622			$new_query .= $split_query[ $key - 2 ] . $split_query[ $key - 1 ] . $placeholder;
1623
1624			$key += 3;
1625			++$arg_id;
1626		}
1627
1628		// Replace $query; and add remaining $query characters, or index 0 if there were no placeholders.
1629		$query = $new_query . $split_query[ $key - 2 ];
1630
1631		$dual_use = array_intersect( $arg_identifiers, $arg_strings );
1632
1633		if ( count( $dual_use ) > 0 ) {
1634			wp_load_translations_early();
1635
1636			$used_placeholders = array();
1637
1638			$key    = 2;
1639			$arg_id = 0;
1640			// Parse again (only used when there is an error).
1641			while ( $key < $split_query_count ) {
1642				$placeholder = $split_query[ $key ];
1643
1644				$format = substr( $placeholder, 1, -1 );
1645
1646				$argnum_pos = strpos( $format, '$' );
1647
1648				if ( false !== $argnum_pos ) {
1649					$arg_pos = ( ( (int) substr( $format, 0, $argnum_pos ) ) - 1 );
1650				} else {
1651					$arg_pos = $arg_id;
1652				}
1653
1654				$used_placeholders[ $arg_pos ][] = $placeholder;
1655
1656				$key += 3;
1657				++$arg_id;
1658			}
1659
1660			$conflicts = array();
1661			foreach ( $dual_use as $arg_pos ) {
1662				$conflicts[] = implode( ' and ', $used_placeholders[ $arg_pos ] );
1663			}
1664
1665			_doing_it_wrong(
1666				'wpdb::prepare',
1667				sprintf(
1668					/* translators: %s: A list of placeholders found to be a problem. */
1669					__( 'Arguments cannot be prepared as both an Identifier and Value. Found the following conflicts: %s' ),
1670					implode( ', ', $conflicts )
1671				),
1672				'6.2.0'
1673			);
1674
1675			return;
1676		}
1677
1678		$args_count = count( $args );
1679
1680		if ( $args_count !== $placeholder_count ) {
1681			if ( 1 === $placeholder_count && $passed_as_array ) {
1682				/*
1683				 * If the passed query only expected one argument,
1684				 * but the wrong number of arguments was sent as an array, bail.
1685				 */
1686				wp_load_translations_early();
1687				_doing_it_wrong(
1688					'wpdb::prepare',
1689					__( 'The query only expected one placeholder, but an array of multiple placeholders was sent.' ),
1690					'4.9.0'
1691				);
1692
1693				return;
1694			} else {
1695				/*
1696				 * If we don't have the right number of placeholders,
1697				 * but they were passed as individual arguments,
1698				 * or we were expecting multiple arguments in an array, throw a warning.
1699				 */
1700				wp_load_translations_early();
1701				_doing_it_wrong(
1702					'wpdb::prepare',
1703					sprintf(
1704						/* translators: 1: Number of placeholders, 2: Number of arguments passed. */
1705						__( 'The query does not contain the correct number of placeholders (%1$d) for the number of arguments passed (%2$d).' ),
1706						$placeholder_count,
1707						$args_count
1708					),
1709					'4.8.3'
1710				);
1711
1712				/*
1713				 * If we don't have enough arguments to match the placeholders,
1714				 * return an empty string to avoid a fatal error on PHP 8.
1715				 */
1716				if ( $args_count < $placeholder_count ) {
1717					$max_numbered_placeholder = 0;
1718
1719					for ( $i = 2, $l = $split_query_count; $i < $l; $i += 3 ) {
1720						// Assume a leading number is for a numbered placeholder, e.g. '%3$s'.
1721						$argnum = (int) substr( $split_query[ $i ], 1 );
1722
1723						if ( $max_numbered_placeholder < $argnum ) {
1724							$max_numbered_placeholder = $argnum;
1725						}
1726					}
1727
1728					if ( ! $max_numbered_placeholder || $args_count < $max_numbered_placeholder ) {
1729						return '';
1730					}
1731				}
1732			}
1733		}
1734
1735		$args_escaped = array();
1736
1737		foreach ( $args as $i => $value ) {
1738			if ( in_array( $i, $arg_identifiers, true ) ) {
1739				$args_escaped[] = $this->_escape_identifier_value( $value );
1740			} elseif ( is_int( $value ) || is_float( $value ) ) {
1741				$args_escaped[] = $value;
1742			} else {
1743				if ( ! is_scalar( $value ) && ! is_null( $value ) ) {
1744					wp_load_translations_early();
1745					_doing_it_wrong(
1746						'wpdb::prepare',
1747						sprintf(
1748							/* translators: %s: Value type. */
1749							__( 'Unsupported value type (%s).' ),
1750							gettype( $value )
1751						),
1752						'4.8.2'
1753					);
1754
1755					// Preserving old behavior, where values are escaped as strings.
1756					$value = '';
1757				}
1758
1759				$args_escaped[] = $this->_real_escape( $value );
1760			}
1761		}
1762
1763		$query = vsprintf( $query, $args_escaped );
1764
1765		return $this->add_placeholder_escape( $query );
1766	}
1767
1768	/**
1769	 * First half of escaping for `LIKE` special characters `%` and `_` before preparing for SQL.
1770	 *
1771	 * Use this only before wpdb::prepare() or esc_sql(). Reversing the order is very bad for security.
1772	 *
1773	 * Example Prepared Statement:
1774	 *
1775	 *     $wild = '%';
1776	 *     $find = 'only 43% of planets';
1777	 *     $like = $wild . $wpdb->esc_like( $find ) . $wild;
1778	 *     $sql  = $wpdb->prepare( "SELECT * FROM $wpdb->posts WHERE post_content LIKE %s", $like );
1779	 *
1780	 * Example Escape Chain:
1781	 *
1782	 *     $sql  = esc_sql( $wpdb->esc_like( $input ) );
1783	 *
1784	 * @since 4.0.0
1785	 *
1786	 * @param string $text The raw text to be escaped. The input typed by the user
1787	 *                     should have no extra or deleted slashes.
1788	 * @return string Text in the form of a LIKE phrase. The output is not SQL safe.
1789	 *                Call wpdb::prepare() or wpdb::_real_escape() next.
1790	 */
1791	public function esc_like( $text ) {
1792		return addcslashes( $text, '_%\\' );
1793	}
1794
1795	/**
1796	 * Prints SQL/DB error.
1797	 *
1798	 * @since 0.71
1799	 *
1800	 * @global array $EZSQL_ERROR Stores error information of query and error string.
1801	 *
1802	 * @param string $str The error to display.
1803	 * @return void|false Void if the showing of errors is enabled, false if disabled.
1804	 */
1805	public function print_error( $str = '' ) {
1806		global $EZSQL_ERROR;
1807
1808		if ( ! $str ) {
1809			$str = mysqli_error( $this->dbh );
1810		}
1811
1812		$EZSQL_ERROR[] = array(
1813			'query'     => $this->last_query,
1814			'error_str' => $str,
1815		);
1816
1817		if ( $this->suppress_errors ) {
1818			return false;
1819		}
1820
1821		$caller = $this->get_caller();
1822		if ( $caller ) {
1823			// Not translated, as this will only appear in the error log.
1824			$error_str = sprintf( 'WordPress database error %1$s for query %2$s made by %3$s', $str, $this->last_query, $caller );
1825		} else {
1826			$error_str = sprintf( 'WordPress database error %1$s for query %2$s', $str, $this->last_query );
1827		}
1828
1829		error_log( $error_str );
1830
1831		// Are we showing errors?
1832		if ( ! $this->show_errors ) {
1833			return false;
1834		}
1835
1836		wp_load_translations_early();
1837
1838		// If there is an error then take note of it.
1839		if ( is_multisite() ) {
1840			$msg = sprintf(
1841				"%s [%s]\n%s\n",
1842				__( 'WordPress database error:' ),
1843				$str,
1844				$this->last_query
1845			);
1846
1847			if ( defined( 'ERRORLOGFILE' ) ) {
1848				error_log( $msg, 3, ERRORLOGFILE );
1849			}
1850			if ( defined( 'DIEONDBERROR' ) ) {
1851				wp_die( $msg );
1852			}
1853		} else {
1854			$str   = htmlspecialchars( $str, ENT_QUOTES );
1855			$query = htmlspecialchars( $this->last_query, ENT_QUOTES );
1856
1857			printf(
1858				'<div id="error"><p class="wpdberror"><strong>%s</strong> [%s]<br /><code>%s</code></p></div>',
1859				__( 'WordPress database error:' ),
1860				$str,
1861				$query
1862			);
1863		}
1864	}
1865
1866	/**
1867	 * Enables showing of database errors.
1868	 *
1869	 * This function should be used only to enable showing of errors.
1870	 * wpdb::hide_errors() should be used instead for hiding errors.
1871	 *
1872	 * @since 0.71
1873	 *
1874	 * @see wpdb::hide_errors()
1875	 *
1876	 * @param bool $show Optional. Whether to show errors. Default true.
1877	 * @return bool Whether showing of errors was previously active.
1878	 */
1879	public function show_errors( $show = true ) {
1880		$errors            = $this->show_errors;
1881		$this->show_errors = $show;
1882		return $errors;
1883	}
1884
1885	/**
1886	 * Disables showing of database errors.
1887	 *
1888	 * By default database errors are not shown.
1889	 *
1890	 * @since 0.71
1891	 *
1892	 * @see wpdb::show_errors()
1893	 *
1894	 * @return bool Whether showing of errors was previously active.
1895	 */
1896	public function hide_errors() {
1897		$show              = $this->show_errors;
1898		$this->show_errors = false;
1899		return $show;
1900	}
1901
1902	/**
1903	 * Enables or disables suppressing of database errors.
1904	 *
1905	 * By default database errors are suppressed.
1906	 *
1907	 * @since 2.5.0
1908	 *
1909	 * @see wpdb::hide_errors()
1910	 *
1911	 * @param bool $suppress Optional. Whether to suppress errors. Default true.
1912	 * @return bool Whether suppressing of errors was previously active.
1913	 */
1914	public function suppress_errors( $suppress = true ) {
1915		$errors                = $this->suppress_errors;
1916		$this->suppress_errors = (bool) $suppress;
1917		return $errors;
1918	}
1919
1920	/**
1921	 * Kills cached query results.
1922	 *
1923	 * @since 0.71
1924	 */
1925	public function flush() {
1926		$this->last_result   = array();
1927		$this->col_info      = null;
1928		$this->last_query    = null;
1929		$this->rows_affected = 0;
1930		$this->num_rows      = 0;
1931		$this->last_error    = '';
1932
1933		if ( $this->result instanceof mysqli_result ) {
1934			mysqli_free_result( $this->result );
1935			$this->result = null;
1936
1937			// Confidence check before using the handle.
1938			if ( empty( $this->dbh ) || ! ( $this->dbh instanceof mysqli ) ) {
1939				return;
1940			}
1941
1942			// Clear out any results from a multi-query.
1943			while ( mysqli_more_results( $this->dbh ) ) {
1944				mysqli_next_result( $this->dbh );
1945			}
1946		}
1947	}
1948
1949	/**
1950	 * Connects to and selects database.
1951	 *
1952	 * If `$allow_bail` is false, the lack of database connection will need to be handled manually.
1953	 *
1954	 * @since 3.0.0
1955	 * @since 3.9.0 $allow_bail parameter added.
1956	 *
1957	 * @param bool $allow_bail Optional. Allows the function to bail. Default true.
1958	 * @return bool True with a successful connection, false on failure.
1959	 */
1960	public function db_connect( $allow_bail = true ) {
1961		$this->is_mysql = true;
1962
1963		$client_flags = defined( 'MYSQL_CLIENT_FLAGS' ) ? MYSQL_CLIENT_FLAGS : 0;
1964
1965		/*
1966		 * Switch error reporting off because WordPress handles its own.
1967		 * This is due to the default value change from `MYSQLI_REPORT_OFF`
1968		 * to `MYSQLI_REPORT_ERROR|MYSQLI_REPORT_STRICT` in PHP 8.1.
1969		 */
1970		mysqli_report( MYSQLI_REPORT_OFF );
1971
1972		$this->dbh = mysqli_init();
1973
1974		$host    = $this->dbhost;
1975		$port    = null;
1976		$socket  = null;
1977		$is_ipv6 = false;
1978
1979		$host_data = $this->parse_db_host( $this->dbhost );
1980		if ( $host_data ) {
1981			list( $host, $port, $socket, $is_ipv6 ) = $host_data;
1982		}
1983
1984		/*
1985		 * If using the `mysqlnd` library, the IPv6 address needs to be enclosed
1986		 * in square brackets, whereas it doesn't while using the `libmysqlclient` library.
1987		 * @see https://bugs.php.net/bug.php?id=67563
1988		 */
1989		if ( $is_ipv6 && extension_loaded( 'mysqlnd' ) ) {
1990			$host = "[$host]";
1991		}
1992
1993		if ( WP_DEBUG ) {
1994			mysqli_real_connect( $this->dbh, $host, $this->dbuser, $this->dbpassword, null, $port, $socket, $client_flags );
1995		} else {
1996			// phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
1997			@mysqli_real_connect( $this->dbh, $host, $this->dbuser, $this->dbpassword, null, $port, $socket, $client_flags );
1998		}
1999
2000		if ( $this->dbh->connect_errno ) {
2001			$this->dbh = null;
2002		}
2003
2004		if ( ! $this->dbh && $allow_bail ) {
2005			wp_load_translations_early();
2006
2007			// Load custom DB error template, if present.
2008			if ( file_exists( WP_CONTENT_DIR . '/db-error.php' ) ) {
2009				require_once WP_CONTENT_DIR . '/db-error.php';
2010				die();
2011			}
2012
2013			$message = '<h1>' . __( 'Error establishing a database connection' ) . "</h1>\n";
2014
2015			$message .= '<p>' . sprintf(
2016				/* translators: 1: wp-config.php, 2: Database host. */
2017				__( 'This either means that the username and password information in your %1$s file is incorrect or that contact with the database server at %2$s could not be established. This could mean your host&#8217;s database server is down.' ),
2018				'<code>wp-config.php</code>',
2019				'<code>' . htmlspecialchars( $this->dbhost, ENT_QUOTES ) . '</code>'
2020			) . "</p>\n";
2021
2022			$message .= "<ul>\n";
2023			$message .= '<li>' . __( 'Are you sure you have the correct username and password?' ) . "</li>\n";
2024			$message .= '<li>' . __( 'Are you sure you have typed the correct hostname?' ) . "</li>\n";
2025			$message .= '<li>' . __( 'Are you sure the database server is running?' ) . "</li>\n";
2026			$message .= "</ul>\n";
2027
2028			$message .= '<p>' . sprintf(
2029				/* translators: %s: Support forums URL. */
2030				__( 'If you are unsure what these terms mean you should probably contact your host. If you still need help you can always visit the <a href="%s">WordPress support forums</a>.' ),
2031				__( 'https://wordpress.org/support/forums/' )
2032			) . "</p>\n";
2033
2034			$this->bail( $message, 'db_connect_fail' );
2035
2036			return false;
2037		} elseif ( $this->dbh ) {
2038			if ( ! $this->has_connected ) {
2039				$this->init_charset();
2040			}
2041
2042			$this->has_connected = true;
2043
2044			$this->set_charset( $this->dbh );
2045
2046			$this->ready = true;
2047			$this->set_sql_mode();
2048			$this->select( $this->dbname, $this->dbh );
2049
2050			return true;
2051		}
2052
2053		return false;
2054	}
2055
2056	/**
2057	 * Parses the DB_HOST setting to interpret it for mysqli_real_connect().
2058	 *
2059	 * mysqli_real_connect() doesn't support the host param including a port or socket
2060	 * like mysql_connect() does. This duplicates how mysql_connect() detects a port
2061	 * and/or socket file.
2062	 *
2063	 * @since 4.9.0
2064	 *
2065	 * @param string $host The DB_HOST setting to parse.
2066	 * @return array|false {
2067	 *     Array containing the host, the port, the socket and
2068	 *     whether it is an IPv6 address, in that order.
2069	 *     False if the host couldn't be parsed.
2070	 *
2071	 *     @type string      $0 Host name.
2072	 *     @type string|null $1 Port.
2073	 *     @type string|null $2 Socket.
2074	 *     @type bool        $3 Whether it is an IPv6 address.
2075	 * }
2076	 */
2077	public function parse_db_host( $host ) {
2078		$socket  = null;
2079		$is_ipv6 = false;
2080
2081		// First peel off the socket parameter from the right, if it exists.
2082		$socket_pos = strpos( $host, ':/' );
2083		if ( false !== $socket_pos ) {
2084			$socket = substr( $host, $socket_pos + 1 );
2085			$host   = substr( $host, 0, $socket_pos );
2086		}
2087
2088		/*
2089		 * We need to check for an IPv6 address first.
2090		 * An IPv6 address will always contain at least two colons.
2091		 */
2092		if ( substr_count( $host, ':' ) > 1 ) {
2093			$pattern = '#^(?:\[)?(?P<host>[0-9a-fA-F:]+)(?:\]:(?P<port>[\d]+))?#';
2094			$is_ipv6 = true;
2095		} else {
2096			// We seem to be dealing with an IPv4 address.
2097			$pattern = '#^(?P<host>[^:/]*)(?::(?P<port>[\d]+))?#';
2098		}
2099
2100		$matches = array();
2101		$result  = preg_match( $pattern, $host, $matches );
2102
2103		if ( 1 !== $result ) {
2104			// Couldn't parse the address, bail.
2105			return false;
2106		}
2107
2108		$host = ! empty( $matches['host'] ) ? $matches['host'] : '';
2109		// Port cannot be a string; must be null or an integer.
2110		$port = ! empty( $matches['port'] ) ? absint( $matches['port'] ) : null;
2111
2112		return array( $host, $port, $socket, $is_ipv6 );
2113	}
2114
2115	/**
2116	 * Checks that the connection to the database is still up. If not, try to reconnect.
2117	 *
2118	 * If this function is unable to reconnect, it will forcibly die, or if called
2119	 * after the {@see 'template_redirect'} hook has been fired, return false instead.
2120	 *
2121	 * If `$allow_bail` is false, the lack of database connection will need to be handled manually.
2122	 *
2123	 * @since 3.9.0
2124	 *
2125	 * @param bool $allow_bail Optional. Allows the function to bail. Default true.
2126	 * @return bool|void True if the connection is up.
2127	 */
2128	public function check_connection( $allow_bail = true ) {
2129		// Check if the connection is alive.
2130		if ( ! empty( $this->dbh ) && mysqli_query( $this->dbh, 'DO 1' ) !== false ) {
2131			return true;
2132		}
2133
2134		$error_reporting = false;
2135
2136		// Disable warnings, as we don't want to see a multitude of "unable to connect" messages.
2137		if ( WP_DEBUG ) {
2138			$error_reporting = error_reporting();
2139			error_reporting( $error_reporting & ~E_WARNING );
2140		}
2141
2142		for ( $tries = 1; $tries <= $this->reconnect_retries; $tries++ ) {
2143			/*
2144			 * On the last try, re-enable warnings. We want to see a single instance
2145			 * of the "unable to connect" message on the bail() screen, if it appears.
2146			 */
2147			if ( $this->reconnect_retries === $tries && WP_DEBUG ) {
2148				error_reporting( $error_reporting );
2149			}
2150
2151			if ( $this->db_connect( false ) ) {
2152				if ( $error_reporting ) {
2153					error_reporting( $error_reporting );
2154				}
2155
2156				return true;
2157			}
2158
2159			sleep( 1 );
2160		}
2161
2162		/*
2163		 * If template_redirect has already happened, it's too late for wp_die()/dead_db().
2164		 * Let's just return and hope for the best.
2165		 */
2166		if ( did_action( 'template_redirect' ) ) {
2167			return false;
2168		}
2169
2170		if ( ! $allow_bail ) {
2171			return false;
2172		}
2173
2174		wp_load_translations_early();
2175
2176		$message = '<h1>' . __( 'Error reconnecting to the database' ) . "</h1>\n";
2177
2178		$message .= '<p>' . sprintf(
2179			/* translators: %s: Database host. */
2180			__( 'This means that the contact with the database server at %s was lost. This could mean your host&#8217;s database server is down.' ),
2181			'<code>' . htmlspecialchars( $this->dbhost, ENT_QUOTES ) . '</code>'
2182		) . "</p>\n";
2183
2184		$message .= "<ul>\n";
2185		$message .= '<li>' . __( 'Are you sure the database server is running?' ) . "</li>\n";
2186		$message .= '<li>' . __( 'Are you sure the database server is not under particularly heavy load?' ) . "</li>\n";
2187		$message .= "</ul>\n";
2188
2189		$message .= '<p>' . sprintf(
2190			/* translators: %s: Support forums URL. */
2191			__( 'If you are unsure what these terms mean you should probably contact your host. If you still need help you can always visit the <a href="%s">WordPress support forums</a>.' ),
2192			__( 'https://wordpress.org/support/forums/' )
2193		) . "</p>\n";
2194
2195		// We weren't able to reconnect, so we better bail.
2196		$this->bail( $message, 'db_connect_fail' );
2197
2198		/*
2199		 * Call dead_db() if bail didn't die, because this database is no more.
2200		 * It has ceased to be (at least temporarily).
2201		 */
2202		dead_db();
2203	}
2204
2205	/**
2206	 * Performs a database query, using current database connection.
2207	 *
2208	 * More information can be found on the documentation page.
2209	 *
2210	 * @since 0.71
2211	 *
2212	 * @link https://developer.wordpress.org/reference/classes/wpdb/
2213	 *
2214	 * @param string $query Database query.
2215	 * @return int|bool Boolean true for CREATE, ALTER, TRUNCATE and DROP queries. Number of rows
2216	 *                  affected/selected for all other queries. Boolean false on error.
2217	 */
2218	public function query( $query ) {
2219		if ( ! $this->ready ) {
2220			$this->check_current_query = true;
2221			return false;
2222		}
2223
2224		/**
2225		 * Filters the database query.
2226		 *
2227		 * Some queries are made before the plugins have been loaded,
2228		 * and thus cannot be filtered with this method.
2229		 *
2230		 * @since 2.1.0
2231		 *
2232		 * @param string $query Database query.
2233		 */
2234		$query = apply_filters( 'query', $query );
2235
2236		if ( ! $query ) {
2237			$this->insert_id = 0;
2238			return false;
2239		}
2240
2241		$this->flush();
2242
2243		// Log how the function was called.
2244		$this->func_call = "\$db->query(\"$query\")";
2245
2246		// If we're writing to the database, make sure the query will write safely.
2247		if ( $this->check_current_query && ! $this->check_ascii( $query ) ) {
2248			$stripped_query = $this->strip_invalid_text_from_query( $query );
2249			/*
2250			 * strip_invalid_text_from_query() can perform queries, so we need
2251			 * to flush again, just to make sure everything is clear.
2252			 */
2253			$this->flush();
2254			if ( $stripped_query !== $query ) {
2255				$this->insert_id  = 0;
2256				$this->last_query = $query;
2257
2258				wp_load_translations_early();
2259
2260				$this->last_error = __( 'WordPress database error: Could not perform query because it contains invalid data.' );
2261
2262				return false;
2263			}
2264		}
2265
2266		$this->check_current_query = true;
2267
2268		// Keep track of the last query for debug.
2269		$this->last_query = $query;
2270
2271		$this->_do_query( $query );
2272
2273		// Database server has gone away, try to reconnect.
2274		$mysql_errno = 0;
2275
2276		if ( $this->dbh instanceof mysqli ) {
2277			$mysql_errno = mysqli_errno( $this->dbh );
2278		} else {
2279			/*
2280			 * $dbh is defined, but isn't a real connection.
2281			 * Something has gone horribly wrong, let's try a reconnect.
2282			 */
2283			$mysql_errno = 2006;
2284		}
2285
2286		if ( empty( $this->dbh ) || 2006 === $mysql_errno ) {
2287			if ( $this->check_connection() ) {
2288				$this->_do_query( $query );
2289			} else {
2290				$this->insert_id = 0;
2291				return false;
2292			}
2293		}
2294
2295		// If there is an error then take note of it.
2296		if ( $this->dbh instanceof mysqli ) {
2297			$this->last_error = mysqli_error( $this->dbh );
2298		} else {
2299			$this->last_error = __( 'Unable to retrieve the error message from the database server' );
2300		}
2301
2302		if ( $this->last_error ) {
2303			// Clear insert_id on a subsequent failed insert.
2304			if ( $this->insert_id && preg_match( '/^\s*(insert|replace)\s/i', $query ) ) {
2305				$this->insert_id = 0;
2306			}
2307
2308			$this->print_error();
2309			return false;
2310		}
2311
2312		if ( preg_match( '/^\s*(create|alter|truncate|drop)\s/i', $query ) ) {
2313			$return_val = $this->result;
2314		} elseif ( preg_match( '/^\s*(insert|delete|update|replace)\s/i', $query ) ) {
2315			$this->rows_affected = mysqli_affected_rows( $this->dbh );
2316
2317			// Take note of the insert_id.
2318			if ( preg_match( '/^\s*(insert|replace)\s/i', $query ) ) {
2319				$this->insert_id = mysqli_insert_id( $this->dbh );
2320			}
2321
2322			// Return number of rows affected.
2323			$return_val = $this->rows_affected;
2324		} else {
2325			$num_rows = 0;
2326
2327			if ( $this->result instanceof mysqli_result ) {
2328				while ( $row = mysqli_fetch_object( $this->result ) ) {
2329					$this->last_result[ $num_rows ] = $row;
2330					++$num_rows;
2331				}
2332			}
2333
2334			// Log and return the number of rows selected.
2335			$this->num_rows = $num_rows;
2336			$return_val     = $num_rows;
2337		}
2338
2339		return $return_val;
2340	}
2341
2342	/**
2343	 * Internal function to perform the mysqli_query() call.
2344	 *
2345	 * @since 3.9.0
2346	 *
2347	 * @see wpdb::query()
2348	 *
2349	 * @param string $query The query to run.
2350	 */
2351	private function _do_query( $query ) {
2352		if ( defined( 'SAVEQUERIES' ) && SAVEQUERIES ) {
2353			$this->timer_start();
2354		}
2355
2356		if ( ! empty( $this->dbh ) ) {
2357			$this->result = mysqli_query( $this->dbh, $query );
2358		}
2359
2360		++$this->num_queries;
2361
2362		if ( defined( 'SAVEQUERIES' ) && SAVEQUERIES ) {
2363			$this->log_query(
2364				$query,
2365				$this->timer_stop(),
2366				$this->get_caller(),
2367				$this->time_start,
2368				array()
2369			);
2370		}
2371	}
2372
2373	/**
2374	 * Logs query data.
2375	 *
2376	 * @since 5.3.0
2377	 *
2378	 * @param string $query           The query's SQL.
2379	 * @param float  $query_time      Total time spent on the query, in seconds.
2380	 * @param string $query_callstack Comma-separated list of the calling functions.
2381	 * @param float  $query_start     Unix timestamp of the time at the start of the query.
2382	 * @param array  $query_data      Custom query data.
2383	 */
2384	public function log_query( $query, $query_time, $query_callstack, $query_start, $query_data ) {
2385		/**
2386		 * Filters the custom data to log alongside a query.
2387		 *
2388		 * Caution should be used when modifying any of this data, it is recommended that any additional
2389		 * information you need to store about a query be added as a new associative array element.
2390		 *
2391		 * @since 5.3.0
2392		 *
2393		 * @param array  $query_data      Custom query data.
2394		 * @param string $query           The query's SQL.
2395		 * @param float  $query_time      Total time spent on the query, in seconds.
2396		 * @param string $query_callstack Comma-separated list of the calling functions.
2397		 * @param float  $query_start     Unix timestamp of the time at the start of the query.
2398		 */
2399		$query_data = apply_filters( 'log_query_custom_data', $query_data, $query, $query_time, $query_callstack, $query_start );
2400
2401		$this->queries[] = array(
2402			$query,
2403			$query_time,
2404			$query_callstack,
2405			$query_start,
2406			$query_data,
2407		);
2408	}
2409
2410	/**
2411	 * Generates and returns a placeholder escape string for use in queries returned by ::prepare().
2412	 *
2413	 * @since 4.8.3
2414	 *
2415	 * @return string String to escape placeholders.
2416	 */
2417	public function placeholder_escape() {
2418		static $placeholder;
2419
2420		if ( ! $placeholder ) {
2421			// Old WP installs may not have AUTH_SALT defined.
2422			$salt = defined( 'AUTH_SALT' ) && AUTH_SALT ? AUTH_SALT : (string) rand();
2423
2424			$placeholder = '{' . hash_hmac( 'sha256', uniqid( $salt, true ), $salt ) . '}';
2425		}
2426
2427		/*
2428		 * Add the filter to remove the placeholder escaper. Uses priority 0, so that anything
2429		 * else attached to this filter will receive the query with the placeholder string removed.
2430		 */
2431		if ( false === has_filter( 'query', array( $this, 'remove_placeholder_escape' ) ) ) {
2432			add_filter( 'query', array( $this, 'remove_placeholder_escape' ), 0 );
2433		}
2434
2435		return $placeholder;
2436	}
2437
2438	/**
2439	 * Adds a placeholder escape string, to escape anything that resembles a printf() placeholder.
2440	 *
2441	 * @since 4.8.3
2442	 *
2443	 * @param string $query The query to escape.
2444	 * @return string The query with the placeholder escape string inserted where necessary.
2445	 */
2446	public function add_placeholder_escape( $query ) {
2447		/*
2448		 * To prevent returning anything that even vaguely resembles a placeholder,
2449		 * we clobber every % we can find.
2450		 */
2451		return str_replace( '%', $this->placeholder_escape(), $query );
2452	}
2453
2454	/**
2455	 * Removes the placeholder escape strings from a query.
2456	 *
2457	 * @since 4.8.3
2458	 *
2459	 * @param string $query The query from which the placeholder will be removed.
2460	 * @return string The query with the placeholder removed.
2461	 */
2462	public function remove_placeholder_escape( $query ) {
2463		return str_replace( $this->placeholder_escape(), '%', $query );
2464	}
2465
2466	/**
2467	 * Inserts a row into the table.
2468	 *
2469	 * Examples:
2470	 *
2471	 *     $wpdb->insert(
2472	 *         'table',
2473	 *         array(
2474	 *             'column1' => 'foo',
2475	 *             'column2' => 'bar',
2476	 *         )
2477	 *     );
2478	 *     $wpdb->insert(
2479	 *         'table',
2480	 *         array(
2481	 *             'column1' => 'foo',
2482	 *             'column2' => 1337,
2483	 *         ),
2484	 *         array(
2485	 *             '%s',
2486	 *             '%d',
2487	 *         )
2488	 *     );
2489	 *
2490	 * @since 2.5.0
2491	 *
2492	 * @see wpdb::prepare()
2493	 * @see wpdb::$field_types
2494	 * @see wp_set_wpdb_vars()
2495	 *
2496	 * @param string          $table  Table name.
2497	 * @param array           $data   Data to insert (in column => value pairs).
2498	 *                                Both `$data` columns and `$data` values should be "raw" (neither should be SQL escaped).
2499	 *                                Sending a null value will cause the column to be set to NULL - the corresponding
2500	 *                                format is ignored in this case.
2501	 * @param string[]|string $format Optional. An array of formats to be mapped to each of the value in `$data`.
2502	 *                                If string, that format will be used for all of the values in `$data`.
2503	 *                                A format is one of '%d', '%f', '%s' (integer, float, string).
2504	 *                                If omitted, all values in `$data` will be treated as strings unless otherwise
2505	 *                                specified in wpdb::$field_types. Default null.
2506	 * @return int|false The number of rows inserted, or false on error.
2507	 */
2508	public function insert( $table, $data, $format = null ) {
2509		return $this->_insert_replace_helper( $table, $data, $format, 'INSERT' );
2510	}
2511
2512	/**
2513	 * Replaces a row in the table or inserts it if it does not exist, based on a PRIMARY KEY or a UNIQUE index.
2514	 *
2515	 * A REPLACE works exactly like an INSERT, except that if an old row in the table has the same value as a new row
2516	 * for a PRIMARY KEY or a UNIQUE index, the old row is deleted before the new row is inserted.
2517	 *
2518	 * Examples:
2519	 *
2520	 *     $wpdb->replace(
2521	 *         'table',
2522	 *         array(
2523	 *             'ID'      => 123,
2524	 *             'column1' => 'foo',
2525	 *             'column2' => 'bar',
2526	 *         )
2527	 *     );
2528	 *     $wpdb->replace(
2529	 *         'table',
2530	 *         array(
2531	 *             'ID'      => 456,
2532	 *             'column1' => 'foo',
2533	 *             'column2' => 1337,
2534	 *         ),
2535	 *         array(
2536	 *             '%d',
2537	 *             '%s',
2538	 *             '%d',
2539	 *         )
2540	 *     );
2541	 *
2542	 * @since 3.0.0
2543	 *
2544	 * @see wpdb::prepare()
2545	 * @see wpdb::$field_types
2546	 * @see wp_set_wpdb_vars()
2547	 *
2548	 * @param string          $table  Table name.
2549	 * @param array           $data   Data to insert (in column => value pairs).
2550	 *                                Both `$data` columns and `$data` values should be "raw" (neither should be SQL escaped).
2551	 *                                A primary key or unique index is required to perform a replace operation.
2552	 *                                Sending a null value will cause the column to be set to NULL - the corresponding
2553	 *                                format is ignored in this case.
2554	 * @param string[]|string $format Optional. An array of formats to be mapped to each of the value in `$data`.
2555	 *                                If string, that format will be used for all of the values in `$data`.
2556	 *                                A format is one of '%d', '%f', '%s' (integer, float, string).
2557	 *                                If omitted, all values in `$data` will be treated as strings unless otherwise
2558	 *                                specified in wpdb::$field_types. Default null.
2559	 * @return int|false The number of rows affected, or false on error.
2560	 */
2561	public function replace( $table, $data, $format = null ) {
2562		return $this->_insert_replace_helper( $table, $data, $format, 'REPLACE' );
2563	}
2564
2565	/**
2566	 * Helper function for insert and replace.
2567	 *
2568	 * Runs an insert or replace query based on `$type` argument.
2569	 *
2570	 * @since 3.0.0
2571	 *
2572	 * @see wpdb::prepare()
2573	 * @see wpdb::$field_types
2574	 * @see wp_set_wpdb_vars()
2575	 *
2576	 * @param string          $table  Table name.
2577	 * @param array           $data   Data to insert (in column => value pairs).
2578	 *                                Both `$data` columns and `$data` values should be "raw" (neither should be SQL escaped).
2579	 *                                Sending a null value will cause the column to be set to NULL - the corresponding
2580	 *                                format is ignored in this case.
2581	 * @param string[]|string $format Optional. An array of formats to be mapped to each of the value in `$data`.
2582	 *                                If string, that format will be used for all of the values in `$data`.
2583	 *                                A format is one of '%d', '%f', '%s' (integer, float, string).
2584	 *                                If omitted, all values in `$data` will be treated as strings unless otherwise
2585	 *                                specified in wpdb::$field_types. Default null.
2586	 * @param string          $type   Optional. Type of operation. Either 'INSERT' or 'REPLACE'.
2587	 *                                Default 'INSERT'.
2588	 * @return int|false The number of rows affected, or false on error.
2589	 */
2590	public function _insert_replace_helper( $table, $data, $format = null, $type = 'INSERT' ) {
2591		$this->insert_id = 0;
2592
2593		if ( ! in_array( strtoupper( $type ), array( 'REPLACE', 'INSERT' ), true ) ) {
2594			return false;
2595		}
2596
2597		$data = $this->process_fields( $table, $data, $format );
2598		if ( false === $data ) {
2599			return false;
2600		}
2601
2602		$formats = array();
2603		$values  = array();
2604		foreach ( $data as $value ) {
2605			if ( is_null( $value['value'] ) ) {
2606				$formats[] = 'NULL';
2607				continue;
2608			}
2609
2610			$formats[] = $value['format'];
2611			$values[]  = $value['value'];
2612		}
2613
2614		$fields  = '`' . implode( '`, `', array_keys( $data ) ) . '`';
2615		$formats = implode( ', ', $formats );
2616
2617		$sql = "$type INTO `$table` ($fields) VALUES ($formats)";
2618
2619		$this->check_current_query = false;
2620		return $this->query( $this->prepare( $sql, $values ) );
2621	}
2622
2623	/**
2624	 * Updates a row in the table.
2625	 *
2626	 * Examples:
2627	 *
2628	 *     $wpdb->update(
2629	 *         'table',
2630	 *         array(
2631	 *             'column1' => 'foo',
2632	 *             'column2' => 'bar',
2633	 *         ),
2634	 *         array(
2635	 *             'ID' => 1,
2636	 *         )
2637	 *     );
2638	 *     $wpdb->update(
2639	 *         'table',
2640	 *         array(
2641	 *             'column1' => 'foo',
2642	 *             'column2' => 1337,
2643	 *         ),
2644	 *         array(
2645	 *             'ID' => 1,
2646	 *         ),
2647	 *         array(
2648	 *             '%s',
2649	 *             '%d',
2650	 *         ),
2651	 *         array(
2652	 *             '%d',
2653	 *         )
2654	 *     );
2655	 *
2656	 * @since 2.5.0
2657	 *
2658	 * @see wpdb::prepare()
2659	 * @see wpdb::$field_types
2660	 * @see wp_set_wpdb_vars()
2661	 *
2662	 * @param string          $table        Table name.
2663	 * @param array           $data         Data to update (in column => value pairs).
2664	 *                                      Both $data columns and $data values should be "raw" (neither should be SQL escaped).
2665	 *                                      Sending a null value will cause the column to be set to NULL - the corresponding
2666	 *                                      format is ignored in this case.
2667	 * @param array           $where        A named array of WHERE clauses (in column => value pairs).
2668	 *                                      Multiple clauses will be joined with ANDs.
2669	 *                                      Both $where columns and $where values should be "raw".
2670	 *                                      Sending a null value will create an IS NULL comparison - the corresponding
2671	 *                                      format will be ignored in this case.
2672	 * @param string[]|string $format       Optional. An array of formats to be mapped to each of the values in $data.
2673	 *                                      If string, that format will be used for all of the values in $data.
2674	 *                                      A format is one of '%d', '%f', '%s' (integer, float, string).
2675	 *                                      If omitted, all values in $data will be treated as strings unless otherwise
2676	 *                                      specified in wpdb::$field_types. Default null.
2677	 * @param string[]|string $where_format Optional. An array of formats to be mapped to each of the values in $where.
2678	 *                                      If string, that format will be used for all of the items in $where.
2679	 *                                      A format is one of '%d', '%f', '%s' (integer, float, string).
2680	 *                                      If omitted, all values in $where will be treated as strings unless otherwise
2681	 *                                      specified in wpdb::$field_types. Default null.
2682	 * @return int|false The number of rows updated, or false on error.
2683	 */
2684	public function update( $table, $data, $where, $format = null, $where_format = null ) {
2685		if ( ! is_array( $data ) || ! is_array( $where ) ) {
2686			return false;
2687		}
2688
2689		$data = $this->process_fields( $table, $data, $format );
2690		if ( false === $data ) {
2691			return false;
2692		}
2693		$where = $this->process_fields( $table, $where, $where_format );
2694		if ( false === $where ) {
2695			return false;
2696		}
2697
2698		$fields     = array();
2699		$conditions = array();
2700		$values     = array();
2701		foreach ( $data as $field => $value ) {
2702			if ( is_null( $value['value'] ) ) {
2703				$fields[] = "`$field` = NULL";
2704				continue;
2705			}
2706
2707			$fields[] = "`$field` = " . $value['format'];
2708			$values[] = $value['value'];
2709		}
2710		foreach ( $where as $field => $value ) {
2711			if ( is_null( $value['value'] ) ) {
2712				$conditions[] = "`$field` IS NULL";
2713				continue;
2714			}
2715
2716			$conditions[] = "`$field` = " . $value['format'];
2717			$values[]     = $value['value'];
2718		}
2719
2720		$fields     = implode( ', ', $fields );
2721		$conditions = implode( ' AND ', $conditions );
2722
2723		$sql = "UPDATE `$table` SET $fields WHERE $conditions";
2724
2725		$this->check_current_query = false;
2726		return $this->query( $this->prepare( $sql, $values ) );
2727	}
2728
2729	/**
2730	 * Deletes a row in the table.
2731	 *
2732	 * Examples:
2733	 *
2734	 *     $wpdb->delete(
2735	 *         'table',
2736	 *         array(
2737	 *             'ID' => 1,
2738	 *         )
2739	 *     );
2740	 *     $wpdb->delete(
2741	 *         'table',
2742	 *         array(
2743	 *             'ID' => 1,
2744	 *         ),
2745	 *         array(
2746	 *             '%d',
2747	 *         )
2748	 *     );
2749	 *
2750	 * @since 3.4.0
2751	 *
2752	 * @see wpdb::prepare()
2753	 * @see wpdb::$field_types
2754	 * @see wp_set_wpdb_vars()
2755	 *
2756	 * @param string          $table        Table name.
2757	 * @param array           $where        A named array of WHERE clauses (in column => value pairs).
2758	 *                                      Multiple clauses will be joined with ANDs.
2759	 *                                      Both $where columns and $where values should be "raw".
2760	 *                                      Sending a null value will create an IS NULL comparison - the corresponding
2761	 *                                      format will be ignored in this case.
2762	 * @param string[]|string $where_format Optional. An array of formats to be mapped to each of the values in $where.
2763	 *                                      If string, that format will be used for all of the items in $where.
2764	 *                                      A format is one of '%d', '%f', '%s' (integer, float, string).
2765	 *                                      If omitted, all values in $data will be treated as strings unless otherwise
2766	 *                                      specified in wpdb::$field_types. Default null.
2767	 * @return int|false The number of rows deleted, or false on error.
2768	 */
2769	public function delete( $table, $where, $where_format = null ) {
2770		if ( ! is_array( $where ) ) {
2771			return false;
2772		}
2773
2774		$where = $this->process_fields( $table, $where, $where_format );
2775		if ( false === $where ) {
2776			return false;
2777		}
2778
2779		$conditions = array();
2780		$values     = array();
2781		foreach ( $where as $field => $value ) {
2782			if ( is_null( $value['value'] ) ) {
2783				$conditions[] = "`$field` IS NULL";
2784				continue;
2785			}
2786
2787			$conditions[] = "`$field` = " . $value['format'];
2788			$values[]     = $value['value'];
2789		}
2790
2791		$conditions = implode( ' AND ', $conditions );
2792
2793		$sql = "DELETE FROM `$table` WHERE $conditions";
2794
2795		$this->check_current_query = false;
2796		return $this->query( $this->prepare( $sql, $values ) );
2797	}
2798
2799	/**
2800	 * Processes arrays of field/value pairs and field formats.
2801	 *
2802	 * This is a helper method for wpdb's CRUD methods, which take field/value pairs
2803	 * for inserts, updates, and where clauses. This method first pairs each value
2804	 * with a format. Then it determines the charset of that field, using that
2805	 * to determine if any invalid text would be stripped. If text is stripped,
2806	 * then field processing is rejected and the query fails.
2807	 *
2808	 * @since 4.2.0
2809	 *
2810	 * @param string          $table  Table name.
2811	 * @param array           $data   Array of values keyed by their field names.
2812	 * @param string[]|string $format Formats or format to be mapped to the values in the data.
2813	 * @return array|false An array of fields that contain paired value and formats.
2814	 *                     False for invalid values.
2815	 */
2816	protected function process_fields( $table, $data, $format ) {
2817		$data = $this->process_field_formats( $data, $format );
2818		if ( false === $data ) {
2819			return false;
2820		}
2821
2822		$data = $this->process_field_charsets( $data, $table );
2823		if ( false === $data ) {
2824			return false;
2825		}
2826
2827		$data = $this->process_field_lengths( $data, $table );
2828		if ( false === $data ) {
2829			return false;
2830		}
2831
2832		$converted_data = $this->strip_invalid_text( $data );
2833
2834		if ( $data !== $converted_data ) {
2835
2836			$problem_fields = array();
2837			foreach ( $data as $field => $value ) {
2838				if ( $value !== $converted_data[ $field ] ) {
2839					$problem_fields[] = $field;
2840				}
2841			}
2842
2843			wp_load_translations_early();
2844
2845			if ( 1 === count( $problem_fields ) ) {
2846				$this->last_error = sprintf(
2847					/* translators: %s: Database field where the error occurred. */
2848					__( 'WordPress database error: Processing the value for the following field failed: %s. The supplied value may be too long or contains invalid data.' ),
2849					reset( $problem_fields )
2850				);
2851			} else {
2852				$this->last_error = sprintf(
2853					/* translators: %s: Database fields where the error occurred. */
2854					__( 'WordPress database error: Processing the values for the following fields failed: %s. The supplied values may be too long or contain invalid data.' ),
2855					implode( ', ', $problem_fields )
2856				);
2857			}
2858
2859			return false;
2860		}
2861
2862		return $data;
2863	}
2864
2865	/**
2866	 * Prepares arrays of value/format pairs as passed to wpdb CRUD methods.
2867	 *
2868	 * @since 4.2.0
2869	 *
2870	 * @param array           $data   Array of values keyed by their field names.
2871	 * @param string[]|string $format Formats or format to be mapped to the values in the data.
2872	 * @return array {
2873	 *     Array of values and formats keyed by their field names.
2874	 *
2875	 *     @type array ...$0 {
2876	 *         Value and format for this field.
2877	 *
2878	 *         @type mixed  $value  The value to be formatted.
2879	 *         @type string $format The format to be mapped to the value.
2880	 *     }
2881	 * }
2882	 */
2883	protected function process_field_formats( $data, $format ) {
2884		$formats          = (array) $format;
2885		$original_formats = $formats;
2886
2887		foreach ( $data as $field => $value ) {
2888			$value = array(
2889				'value'  => $value,
2890				'format' => '%s',
2891			);
2892
2893			if ( ! empty( $format ) ) {
2894				$value['format'] = array_shift( $formats );
2895				if ( ! $value['format'] ) {
2896					$value['format'] = reset( $original_formats );
2897				}
2898			} elseif ( isset( $this->field_types[ $field ] ) ) {
2899				$value['format'] = $this->field_types[ $field ];
2900			}
2901
2902			$data[ $field ] = $value;
2903		}
2904
2905		return $data;
2906	}
2907
2908	/**
2909	 * Adds field charsets to field/value/format arrays generated by wpdb::process_field_formats().
2910	 *
2911	 * @since 4.2.0
2912	 *
2913	 * @param array  $data {
2914	 *     Array of values and formats keyed by their field names,
2915	 *     as it comes from the wpdb::process_field_formats() method.
2916	 *
2917	 *     @type array ...$0 {
2918	 *         Value and format for this field.
2919	 *
2920	 *         @type mixed  $value  The value to be formatted.
2921	 *         @type string $format The format to be mapped to the value.
2922	 *     }
2923	 * }
2924	 * @param string $table Table name.
2925	 * @return array|false {
2926	 *     The same array of data with additional 'charset' keys, or false if
2927	 *     the charset for the table cannot be found.
2928	 *
2929	 *     @type array ...$0 {
2930	 *         Value, format, and charset for this field.
2931	 *
2932	 *         @type mixed        $value   The value to be formatted.
2933	 *         @type string       $format  The format to be mapped to the value.
2934	 *         @type string|false $charset The charset to be used for the value.
2935	 *     }
2936	 * }
2937	 */
2938	protected function process_field_charsets( $data, $table ) {
2939		foreach ( $data as $field => $value ) {
2940			if ( '%d' === $value['format'] || '%f' === $value['format'] ) {
2941				/*
2942				 * We can skip this field if we know it isn't a string.
2943				 * This checks %d/%f versus ! %s because its sprintf() could take more.
2944				 */
2945				$value['charset'] = false;
2946			} else {
2947				$value['charset'] = $this->get_col_charset( $table, $field );
2948				if ( is_wp_error( $value['charset'] ) ) {
2949					return false;
2950				}
2951			}
2952
2953			$data[ $field ] = $value;
2954		}
2955
2956		return $data;
2957	}
2958
2959	/**
2960	 * For string fields, records the maximum string length that field can safely save.
2961	 *
2962	 * @since 4.2.1
2963	 *
2964	 * @param array  $data {
2965	 *     Array of values, formats, and charsets keyed by their field names,
2966	 *     as it comes from the wpdb::process_field_charsets() method.
2967	 *
2968	 *     @type array ...$0 {
2969	 *         Value, format, and charset for this field.
2970	 *
2971	 *         @type mixed        $value   The value to be formatted.
2972	 *         @type string       $format  The format to be mapped to the value.
2973	 *         @type string|false $charset The charset to be used for the value.
2974	 *     }
2975	 * }
2976	 * @param string $table Table name.
2977	 * @return array|false {
2978	 *     The same array of data with additional 'length' keys, or false if
2979	 *     information for the table cannot be found.
2980	 *
2981	 *     @type array ...$0 {
2982	 *         Value, format, charset, and length for this field.
2983	 *
2984	 *         @type mixed        $value   The value to be formatted.
2985	 *         @type string       $format  The format to be mapped to the value.
2986	 *         @type string|false $charset The charset to be used for the value.
2987	 *         @type array|false  $length  {
2988	 *             Information about the maximum length of the value.
2989	 *             False if the column has no length.
2990	 *
2991	 *             @type string $type   One of 'byte' or 'char'.
2992	 *             @type int    $length The column length.
2993	 *         }
2994	 *     }
2995	 * }
2996	 */
2997	protected function process_field_lengths( $data, $table ) {
2998		foreach ( $data as $field => $value ) {
2999			if ( '%d' === $value['format'] || '%f' === $value['format'] ) {
3000				/*
3001				 * We can skip this field if we know it isn't a string.
3002				 * This checks %d/%f versus ! %s because its sprintf() could take more.
3003				 */
3004				$value['length'] = false;
3005			} else {
3006				$value['length'] = $this->get_col_length( $table, $field );
3007				if ( is_wp_error( $value['length'] ) ) {
3008					return false;
3009				}
3010			}
3011
3012			$data[ $field ] = $value;
3013		}
3014
3015		return $data;
3016	}
3017
3018	/**
3019	 * Retrieves one value from the database.
3020	 *
3021	 * Executes a SQL query and returns the value from the SQL result.
3022	 * If the SQL result contains more than one column and/or more than one row,
3023	 * the value in the column and row specified is returned. If $query is null,
3024	 * the value in the specified column and row from the previous SQL result is returned.
3025	 *
3026	 * @since 0.71
3027	 *
3028	 * @param string|null $query Optional. SQL query. Defaults to null, use the result from the previous query.
3029	 * @param int         $x     Optional. Column of value to return. Indexed from 0. Default 0.
3030	 * @param int         $y     Optional. Row of value to return. Indexed from 0. Default 0.
3031	 * @return string|null Database query result (as string), or null on failure.
3032	 */
3033	public function get_var( $query = null, $x = 0, $y = 0 ) {
3034		$this->func_call = "\$db->get_var(\"$query\", $x, $y)";
3035
3036		if ( $query ) {
3037			if ( $this->check_current_query && $this->check_safe_collation( $query ) ) {
3038				$this->check_current_query = false;
3039			}
3040
3041			$this->query( $query );
3042		}
3043
3044		// Extract var out of cached results based on x,y vals.
3045		if ( ! empty( $this->last_result[ $y ] ) ) {
3046			$values = array_values( get_object_vars( $this->last_result[ $y ] ) );
3047		}
3048
3049		// If there is a value return it, else return null.
3050		return ( isset( $values[ $x ] ) && '' !== $values[ $x ] ) ? $values[ $x ] : null;
3051	}
3052
3053	/**
3054	 * Retrieves one row from the database.
3055	 *
3056	 * Executes a SQL query and returns the row from the SQL result.
3057	 *
3058	 * @since 0.71
3059	 *
3060	 * @param string|null $query  SQL query.
3061	 * @param string      $output Optional. The required return type. One of OBJECT, ARRAY_A, or ARRAY_N, which
3062	 *                            correspond to an stdClass object, an associative array, or a numeric array,
3063	 *                            respectively. Default OBJECT.
3064	 * @param int         $y      Optional. Row to return. Indexed from 0. Default 0.
3065	 * @return array|object|null|void Database query result in format specified by $output or null on failure.
3066	 */
3067	public function get_row( $query = null, $output = OBJECT, $y = 0 ) {
3068		$this->func_call = "\$db->get_row(\"$query\",$output,$y)";
3069
3070		if ( $query ) {
3071			if ( $this->check_current_query && $this->check_safe_collation( $query ) ) {
3072				$this->check_current_query = false;
3073			}
3074
3075			$this->query( $query );
3076		} else {
3077			return null;
3078		}
3079
3080		if ( ! isset( $this->last_result[ $y ] ) ) {
3081			return null;
3082		}
3083
3084		if ( OBJECT === $output ) {
3085			return $this->last_result[ $y ] ? $this->last_result[ $y ] : null;
3086		} elseif ( ARRAY_A === $output ) {
3087			return $this->last_result[ $y ] ? get_object_vars( $this->last_result[ $y ] ) : null;
3088		} elseif ( ARRAY_N === $output ) {
3089			return $this->last_result[ $y ] ? array_values( get_object_vars( $this->last_result[ $y ] ) ) : null;
3090		} elseif ( OBJECT === strtoupper( $output ) ) {
3091			// Back compat for OBJECT being previously case-insensitive.
3092			return $this->last_result[ $y ] ? $this->last_result[ $y ] : null;
3093		} else {
3094			$this->print_error( ' $db->get_row(string query, output type, int offset) -- Output type must be one of: OBJECT, ARRAY_A, ARRAY_N' );
3095		}
3096	}
3097
3098	/**
3099	 * Retrieves one column from the database.
3100	 *
3101	 * Executes a SQL query and returns the column from the SQL result.
3102	 * If the SQL result contains more than one column, the column specified is returned.
3103	 * If $query is null, the specified column from the previous SQL result is returned.
3104	 *
3105	 * @since 0.71
3106	 *
3107	 * @param string|null $query Optional. SQL query. Defaults to previous query.
3108	 * @param int         $x     Optional. Column to return. Indexed from 0. Default 0.
3109	 * @return array Database query result. Array indexed from 0 by SQL result row number.
3110	 */
3111	public function get_col( $query = null, $x = 0 ) {
3112		if ( $query ) {
3113			if ( $this->check_current_query && $this->check_safe_collation( $query ) ) {
3114				$this->check_current_query = false;
3115			}
3116
3117			$this->query( $query );
3118		}
3119
3120		$new_array = array();
3121		// Extract the column values.
3122		if ( $this->last_result ) {
3123			for ( $i = 0, $j = count( $this->last_result ); $i < $j; $i++ ) {
3124				$new_array[ $i ] = $this->get_var( null, $x, $i );
3125			}
3126		}
3127		return $new_array;
3128	}
3129
3130	/**
3131	 * Retrieves an entire SQL result set from the database (i.e., many rows).
3132	 *
3133	 * Executes a SQL query and returns the entire SQL result.
3134	 *
3135	 * @since 0.71
3136	 *
3137	 * @param string $query  SQL query.
3138	 * @param string $output Optional. Any of ARRAY_A | ARRAY_N | OBJECT | OBJECT_K constants.
3139	 *                       With one of the first three, return an array of rows indexed
3140	 *                       from 0 by SQL result row number. Each row is an associative array
3141	 *                       (column => value, ...), a numerically indexed array (0 => value, ...),
3142	 *                       or an object ( ->column = value ), respectively. With OBJECT_K,
3143	 *                       return an associative array of row objects keyed by the value
3144	 *                       of each row's first column's value. Duplicate keys are discarded.
3145	 *                       Default OBJECT.
3146	 * @return array|object|null Database query results.
3147	 */
3148	public function get_results( $query = null, $output = OBJECT ) {
3149		$this->func_call = "\$db->get_results(\"$query\", $output)";
3150
3151		if ( $query ) {
3152			if ( $this->check_current_query && $this->check_safe_collation( $query ) ) {
3153				$this->check_current_query = false;
3154			}
3155
3156			$this->query( $query );
3157		} else {
3158			return null;
3159		}
3160
3161		$new_array = array();
3162		if ( OBJECT === $output ) {
3163			// Return an integer-keyed array of row objects.
3164			return $this->last_result;
3165		} elseif ( OBJECT_K === $output ) {
3166			/*
3167			 * Return an array of row objects with keys from column 1.
3168			 * (Duplicates are discarded.)
3169			 */
3170			if ( $this->last_result ) {
3171				foreach ( $this->last_result as $row ) {
3172					$var_by_ref = get_object_vars( $row );
3173					$key        = array_shift( $var_by_ref );
3174					if ( ! isset( $new_array[ $key ] ) ) {
3175						$new_array[ $key ] = $row;
3176					}
3177				}
3178			}
3179			return $new_array;
3180		} elseif ( ARRAY_A === $output || ARRAY_N === $output ) {
3181			// Return an integer-keyed array of...
3182			if ( $this->last_result ) {
3183				if ( ARRAY_N === $output ) {
3184					foreach ( (array) $this->last_result as $row ) {
3185						// ...integer-keyed row arrays.
3186						$new_array[] = array_values( get_object_vars( $row ) );
3187					}
3188				} else {
3189					foreach ( (array) $this->last_result as $row ) {
3190						// ...column name-keyed row arrays.
3191						$new_array[] = get_object_vars( $row );
3192					}
3193				}
3194			}
3195			return $new_array;
3196		} elseif ( strtoupper( $output ) === OBJECT ) {
3197			// Back compat for OBJECT being previously case-insensitive.
3198			return $this->last_result;
3199		}
3200		return null;
3201	}
3202
3203	/**
3204	 * Retrieves the character set for the given table.
3205	 *
3206	 * @since 4.2.0
3207	 *
3208	 * @param string $table Table name.
3209	 * @return string|WP_Error Table character set, WP_Error object if it couldn't be found.
3210	 */
3211	protected function get_table_charset( $table ) {
3212		$tablekey = strtolower( $table );
3213
3214		/**
3215		 * Filters the table charset value before the DB is checked.
3216		 *
3217		 * Returning a non-null value from the filter will effectively short-circuit
3218		 * checking the DB for the charset, returning that value instead.
3219		 *
3220		 * @since 4.2.0
3221		 *
3222		 * @param string|WP_Error|null $charset The character set to use, WP_Error object
3223		 *                                      if it couldn't be found. Default null.
3224		 * @param string               $table   The name of the table being checked.
3225		 */
3226		$charset = apply_filters( 'pre_get_table_charset', null, $table );
3227		if ( null !== $charset ) {
3228			return $charset;
3229		}
3230
3231		if ( isset( $this->table_charset[ $tablekey ] ) ) {
3232			return $this->table_charset[ $tablekey ];
3233		}
3234
3235		$charsets = array();
3236		$columns  = array();
3237
3238		$table_parts = explode( '.', $table );
3239		$table       = '`' . implode( '`.`', $table_parts ) . '`';
3240		$results     = $this->get_results( "SHOW FULL COLUMNS FROM $table" );
3241		if ( ! $results ) {
3242			return new WP_Error( 'wpdb_get_table_charset_failure', __( 'Could not retrieve table charset.' ) );
3243		}
3244
3245		foreach ( $results as $column ) {
3246			$columns[ strtolower( $column->Field ) ] = $column;
3247		}
3248
3249		$this->col_meta[ $tablekey ] = $columns;
3250
3251		foreach ( $columns as $column ) {
3252			if ( ! empty( $column->Collation ) ) {
3253				list( $charset ) = explode( '_', $column->Collation );
3254
3255				$charsets[ strtolower( $charset ) ] = true;
3256			}
3257
3258			list( $type ) = explode( '(', $column->Type );
3259
3260			// A binary/blob means the whole query gets treated like this.
3261			if ( in_array( strtoupper( $type ), array( 'BINARY', 'VARBINARY', 'TINYBLOB', 'MEDIUMBLOB', 'BLOB', 'LONGBLOB' ), true ) ) {
3262				$this->table_charset[ $tablekey ] = 'binary';
3263				return 'binary';
3264			}
3265		}
3266
3267		// utf8mb3 is an alias for utf8.
3268		if ( isset( $charsets['utf8mb3'] ) ) {
3269			$charsets['utf8'] = true;
3270			unset( $charsets['utf8mb3'] );
3271		}
3272
3273		// Check if we have more than one charset in play.
3274		$count = count( $charsets );
3275		if ( 1 === $count ) {
3276			$charset = key( $charsets );
3277		} elseif ( 0 === $count ) {
3278			// No charsets, assume this table can store whatever.
3279			$charset = false;
3280		} else {
3281			// More than one charset. Remove latin1 if present and recalculate.
3282			unset( $charsets['latin1'] );
3283			$count = count( $charsets );
3284			if ( 1 === $count ) {
3285				// Only one charset (besides latin1).
3286				$charset = key( $charsets );
3287			} elseif ( 2 === $count && isset( $charsets['utf8'], $charsets['utf8mb4'] ) ) {
3288				// Two charsets, but they're utf8 and utf8mb4, use utf8.
3289				$charset = 'utf8';
3290			} else {
3291				// Two mixed character sets. ascii.
3292				$charset = 'ascii';
3293			}
3294		}
3295
3296		$this->table_charset[ $tablekey ] = $charset;
3297		return $charset;
3298	}
3299
3300	/**
3301	 * Retrieves the character set for the given column.
3302	 *
3303	 * @since 4.2.0
3304	 *
3305	 * @param string $table  Table name.
3306	 * @param string $column Column name.
3307	 * @return string|false|WP_Error Column character set as a string. False if the column has
3308	 *                               no character set. WP_Error object if there was an error.
3309	 */
3310	public function get_col_charset( $table, $column ) {
3311		$tablekey  = strtolower( $table );
3312		$columnkey = strtolower( $column );
3313
3314		/**
3315		 * Filters the column charset value before the DB is checked.
3316		 *
3317		 * Passing a non-null value to the filter will short-circuit
3318		 * checking the DB for the charset, returning that value instead.
3319		 *
3320		 * @since 4.2.0
3321		 *
3322		 * @param string|null|false|WP_Error $charset The character set to use. Default null.
3323		 * @param string                     $table   The name of the table being checked.
3324		 * @param string                     $column  The name of the column being checked.
3325		 */
3326		$charset = apply_filters( 'pre_get_col_charset', null, $table, $column );
3327		if ( null !== $charset ) {
3328			return $charset;
3329		}
3330
3331		// Skip this entirely if this isn't a MySQL database.
3332		if ( empty( $this->is_mysql ) ) {
3333			return false;
3334		}
3335
3336		if ( empty( $this->table_charset[ $tablekey ] ) ) {
3337			// This primes column information for us.
3338			$table_charset = $this->get_table_charset( $table );
3339			if ( is_wp_error( $table_charset ) ) {
3340				return $table_charset;
3341			}
3342		}
3343
3344		// If still no column information, return the table charset.
3345		if ( empty( $this->col_meta[ $tablekey ] ) ) {
3346			return $this->table_charset[ $tablekey ];
3347		}
3348
3349		// If this column doesn't exist, return the table charset.
3350		if ( empty( $this->col_meta[ $tablekey ][ $columnkey ] ) ) {
3351			return $this->table_charset[ $tablekey ];
3352		}
3353
3354		// Return false when it's not a string column.
3355		if ( empty( $this->col_meta[ $tablekey ][ $columnkey ]->Collation ) ) {
3356			return false;
3357		}
3358
3359		list( $charset ) = explode( '_', $this->col_meta[ $tablekey ][ $columnkey ]->Collation );
3360		return $charset;
3361	}
3362
3363	/**
3364	 * Retrieves the maximum string length allowed in a given column.
3365	 *
3366	 * The length may either be specified as a byte length or a character length.
3367	 *
3368	 * @since 4.2.1
3369	 *
3370	 * @param string $table  Table name.
3371	 * @param string $column Column name.
3372	 * @return array|false|WP_Error {
3373	 *     Array of column length information, false if the column has no length (for
3374	 *     example, numeric column), WP_Error object if there was an error.
3375	 *
3376	 *     @type string $type   One of 'byte' or 'char'.
3377	 *     @type int    $length The column length.
3378	 * }
3379	 */
3380	public function get_col_length( $table, $column ) {
3381		$tablekey  = strtolower( $table );
3382		$columnkey = strtolower( $column );
3383
3384		// Skip this entirely if this isn't a MySQL database.
3385		if ( empty( $this->is_mysql ) ) {
3386			return false;
3387		}
3388
3389		if ( empty( $this->col_meta[ $tablekey ] ) ) {
3390			// This primes column information for us.
3391			$table_charset = $this->get_table_charset( $table );
3392			if ( is_wp_error( $table_charset ) ) {
3393				return $table_charset;
3394			}
3395		}
3396
3397		if ( empty( $this->col_meta[ $tablekey ][ $columnkey ] ) ) {
3398			return false;
3399		}
3400
3401		$typeinfo = explode( '(', $this->col_meta[ $tablekey ][ $columnkey ]->Type );
3402
3403		$type = strtolower( $typeinfo[0] );
3404		if ( ! empty( $typeinfo[1] ) ) {
3405			$length = trim( $typeinfo[1], ')' );
3406		} else {
3407			$length = false;
3408		}
3409
3410		switch ( $type ) {
3411			case 'char':
3412			case 'varchar':
3413				return array(
3414					'type'   => 'char',
3415					'length' => (int) $length,
3416				);
3417
3418			case 'binary':
3419			case 'varbinary':
3420				return array(
3421					'type'   => 'byte',
3422					'length' => (int) $length,
3423				);
3424
3425			case 'tinyblob':
3426			case 'tinytext':
3427				return array(
3428					'type'   => 'byte',
3429					'length' => 255,        // 2^8 - 1
3430				);
3431
3432			case 'blob':
3433			case 'text':
3434				return array(
3435					'type'   => 'byte',
3436					'length' => 65535,      // 2^16 - 1
3437				);
3438
3439			case 'mediumblob':
3440			case 'mediumtext':
3441				return array(
3442					'type'   => 'byte',
3443					'length' => 16777215,   // 2^24 - 1
3444				);
3445
3446			case 'longblob':
3447			case 'longtext':
3448				return array(
3449					'type'   => 'byte',
3450					'length' => 4294967295, // 2^32 - 1
3451				);
3452
3453			default:
3454				return false;
3455		}
3456	}
3457
3458	/**
3459	 * Checks if a string is ASCII.
3460	 *
3461	 * The negative regex is faster for non-ASCII strings, as it allows
3462	 * the search to finish as soon as it encounters a non-ASCII character.
3463	 *
3464	 * @since 4.2.0
3465	 *
3466	 * @param string $input_string String to check.
3467	 * @return bool True if ASCII, false if not.
3468	 */
3469	protected function check_ascii( $input_string ) {
3470		if ( function_exists( 'mb_check_encoding' ) ) {
3471			if ( mb_check_encoding( $input_string, 'ASCII' ) ) {
3472				return true;
3473			}
3474		} elseif ( ! preg_match( '/[^\x00-\x7F]/', $input_string ) ) {
3475			return true;
3476		}
3477
3478		return false;
3479	}
3480
3481	/**
3482	 * Checks if the query is accessing a collation considered safe.
3483	 *
3484	 * @since 4.2.0
3485	 *
3486	 * @param string $query The query to check.
3487	 * @return bool True if the collation is safe, false if it isn't.
3488	 */
3489	protected function check_safe_collation( $query ) {
3490		if ( $this->checking_collation ) {
3491			return true;
3492		}
3493
3494		// We don't need to check the collation for queries that don't read data.
3495		$query = ltrim( $query, "\r\n\t (" );
3496		if ( preg_match( '/^(?:SHOW|DESCRIBE|DESC|EXPLAIN|CREATE)\s/i', $query ) ) {
3497			return true;
3498		}
3499
3500		// All-ASCII queries don't need extra checking.
3501		if ( $this->check_ascii( $query ) ) {
3502			return true;
3503		}
3504
3505		$table = $this->get_table_from_query( $query );
3506		if ( ! $table ) {
3507			return false;
3508		}
3509
3510		$this->checking_collation = true;
3511		$collation                = $this->get_table_charset( $table );
3512		$this->checking_collation = false;
3513
3514		// Tables with no collation, or latin1 only, don't need extra checking.
3515		if ( false === $collation || 'latin1' === $collation ) {
3516			return true;
3517		}
3518
3519		$table = strtolower( $table );
3520		if ( empty( $this->col_meta[ $table ] ) ) {
3521			return false;
3522		}
3523
3524		// If any of the columns don't have one of these collations, it needs more confidence checking.
3525		$safe_collations = array(
3526			'utf8_bin',
3527			'utf8_general_ci',
3528			'utf8mb3_bin',
3529			'utf8mb3_general_ci',
3530			'utf8mb4_bin',
3531			'utf8mb4_general_ci',
3532		);
3533
3534		foreach ( $this->col_meta[ $table ] as $col ) {
3535			if ( empty( $col->Collation ) ) {
3536				continue;
3537			}
3538
3539			if ( ! in_array( $col->Collation, $safe_collations, true ) ) {
3540				return false;
3541			}
3542		}
3543
3544		return true;
3545	}
3546
3547	/**
3548	 * Strips any invalid characters based on value/charset pairs.
3549	 *
3550	 * @since 4.2.0
3551	 *
3552	 * @param array $data Array of value arrays. Each value array has the keys 'value', 'charset', and 'length'.
3553	 *                    An optional 'ascii' key can be set to false to avoid redundant ASCII checks.
3554	 * @return array|WP_Error The $data parameter, with invalid characters removed from each value.
3555	 *                        This works as a passthrough: any additional keys such as 'field' are
3556	 *                        retained in each value array. If we cannot remove invalid characters,
3557	 *                        a WP_Error object is returned.
3558	 */
3559	protected function strip_invalid_text( $data ) {
3560		$db_check_string = false;
3561
3562		foreach ( $data as &$value ) {
3563			$charset = $value['charset'];
3564
3565			if ( is_array( $value['length'] ) ) {
3566				$length                  = $value['length']['length'];
3567				$truncate_by_byte_length = 'byte' === $value['length']['type'];
3568			} else {
3569				$length = false;
3570				/*
3571				 * Since we have no length, we'll never truncate. Initialize the variable to false.
3572				 * True would take us through an unnecessary (for this case) codepath below.
3573				 */
3574				$truncate_by_byte_length = false;
3575			}
3576
3577			// There's no charset to work with.
3578			if ( false === $charset ) {
3579				continue;
3580			}
3581
3582			// Column isn't a string.
3583			if ( ! is_string( $value['value'] ) ) {
3584				continue;
3585			}
3586
3587			$needs_validation = true;
3588			if (
3589				// latin1 can store any byte sequence.
3590				'latin1' === $charset
3591			||
3592				// ASCII is always OK.
3593				( ! isset( $value['ascii'] ) && $this->check_ascii( $value['value'] ) )
3594			) {
3595				$truncate_by_byte_length = true;
3596				$needs_validation        = false;
3597			}
3598
3599			if ( $truncate_by_byte_length ) {
3600				mbstring_binary_safe_encoding();
3601				if ( false !== $length && strlen( $value['value'] ) > $length ) {
3602					$value['value'] = substr( $value['value'], 0, $length );
3603				}
3604				reset_mbstring_encoding();
3605
3606				if ( ! $needs_validation ) {
3607					continue;
3608				}
3609			}
3610
3611			// utf8 can be handled by regex, which is a bunch faster than a DB lookup.
3612			if ( ( 'utf8' === $charset || 'utf8mb3' === $charset || 'utf8mb4' === $charset ) && function_exists( 'mb_strlen' ) ) {
3613				$regex = '/
3614					(
3615						(?: [\x00-\x7F]                  # single-byte sequences   0xxxxxxx
3616						|   [\xC2-\xDF][\x80-\xBF]       # double-byte sequences   110xxxxx 10xxxxxx
3617						|   \xE0[\xA0-\xBF][\x80-\xBF]   # triple-byte sequences   1110xxxx 10xxxxxx * 2
3618						|   [\xE1-\xEC][\x80-\xBF]{2}
3619						|   \xED[\x80-\x9F][\x80-\xBF]
3620						|   [\xEE-\xEF][\x80-\xBF]{2}';
3621
3622				if ( 'utf8mb4' === $charset ) {
3623					$regex .= '
3624						|    \xF0[\x90-\xBF][\x80-\xBF]{2} # four-byte sequences   11110xxx 10xxxxxx * 3
3625						|    [\xF1-\xF3][\x80-\xBF]{3}
3626						|    \xF4[\x80-\x8F][\x80-\xBF]{2}
3627					';
3628				}
3629
3630				$regex         .= '){1,40}                          # ...one or more times
3631					)
3632					| .                                  # anything else
3633					/x';
3634				$value['value'] = preg_replace( $regex, '$1', $value['value'] );
3635
3636				if ( false !== $length && mb_strlen( $value['value'], 'UTF-8' ) > $length ) {
3637					$value['value'] = mb_substr( $value['value'], 0, $length, 'UTF-8' );
3638				}
3639				continue;
3640			}
3641
3642			// We couldn't use any local conversions, send it to the DB.
3643			$value['db']     = true;
3644			$db_check_string = true;
3645		}
3646		unset( $value ); // Remove by reference.
3647
3648		if ( $db_check_string ) {
3649			$queries = array();
3650			foreach ( $data as $col => $value ) {
3651				if ( ! empty( $value['db'] ) ) {
3652					// We're going to need to truncate by characters or bytes, depending on the length value we have.
3653					if ( isset( $value['length']['type'] ) && 'byte' === $value['length']['type'] ) {
3654						// Using binary causes LEFT() to truncate by bytes.
3655						$charset = 'binary';
3656					} else {
3657						$charset = $value['charset'];
3658					}
3659
3660					if ( $this->charset ) {
3661						$connection_charset = $this->charset;
3662					} else {
3663						$connection_charset = mysqli_character_set_name( $this->dbh );
3664					}
3665
3666					if ( is_array( $value['length'] ) ) {
3667						$length          = sprintf( '%.0f', $value['length']['length'] );
3668						$queries[ $col ] = $this->prepare( "CONVERT( LEFT( CONVERT( %s USING $charset ), $length ) USING $connection_charset )", $value['value'] );
3669					} elseif ( 'binary' !== $charset ) {
3670						// If we don't have a length, there's no need to convert binary - it will always return the same result.
3671						$queries[ $col ] = $this->prepare( "CONVERT( CONVERT( %s USING $charset ) USING $connection_charset )", $value['value'] );
3672					}
3673
3674					unset( $data[ $col ]['db'] );
3675				}
3676			}
3677
3678			$sql = array();
3679			foreach ( $queries as $column => $query ) {
3680				if ( ! $query ) {
3681					continue;
3682				}
3683
3684				$sql[] = $query . " AS x_$column";
3685			}
3686
3687			$this->check_current_query = false;
3688			$row                       = $this->get_row( 'SELECT ' . implode( ', ', $sql ), ARRAY_A );
3689			if ( ! $row ) {
3690				return new WP_Error( 'wpdb_strip_invalid_text_failure', __( 'Could not strip invalid text.' ) );
3691			}
3692
3693			foreach ( array_keys( $data ) as $column ) {
3694				if ( isset( $row[ "x_$column" ] ) ) {
3695					$data[ $column ]['value'] = $row[ "x_$column" ];
3696				}
3697			}
3698		}
3699
3700		return $data;
3701	}
3702
3703	/**
3704	 * Strips any invalid characters from the query.
3705	 *
3706	 * @since 4.2.0
3707	 *
3708	 * @param string $query Query to convert.
3709	 * @return string|WP_Error The converted query, or a WP_Error object if the conversion fails.
3710	 */
3711	protected function strip_invalid_text_from_query( $query ) {
3712		// We don't need to check the collation for queries that don't read data.
3713		$trimmed_query = ltrim( $query, "\r\n\t (" );
3714		if ( preg_match( '/^(?:SHOW|DESCRIBE|DESC|EXPLAIN|CREATE)\s/i', $trimmed_query ) ) {
3715			return $query;
3716		}
3717
3718		$table = $this->get_table_from_query( $query );
3719		if ( $table ) {
3720			$charset = $this->get_table_charset( $table );
3721			if ( is_wp_error( $charset ) ) {
3722				return $charset;
3723			}
3724
3725			// We can't reliably strip text from tables containing binary/blob columns.
3726			if ( 'binary' === $charset ) {
3727				return $query;
3728			}
3729		} else {
3730			$charset = $this->charset;
3731		}
3732
3733		$data = array(
3734			'value'   => $query,
3735			'charset' => $charset,
3736			'ascii'   => false,
3737			'length'  => false,
3738		);
3739
3740		$data = $this->strip_invalid_text( array( $data ) );
3741		if ( is_wp_error( $data ) ) {
3742			return $data;
3743		}
3744
3745		return $data[0]['value'];
3746	}
3747
3748	/**
3749	 * Strips any invalid characters from the string for a given table and column.
3750	 *
3751	 * @since 4.2.0
3752	 *
3753	 * @param string $table  Table name.
3754	 * @param string $column Column name.
3755	 * @param string $value  The text to check.
3756	 * @return string|WP_Error The converted string, or a WP_Error object if the conversion fails.
3757	 */
3758	public function strip_invalid_text_for_column( $table, $column, $value ) {
3759		if ( ! is_string( $value ) ) {
3760			return $value;
3761		}
3762
3763		$charset = $this->get_col_charset( $table, $column );
3764		if ( ! $charset ) {
3765			// Not a string column.
3766			return $value;
3767		} elseif ( is_wp_error( $charset ) ) {
3768			// Bail on real errors.
3769			return $charset;
3770		}
3771
3772		$data = array(
3773			$column => array(
3774				'value'   => $value,
3775				'charset' => $charset,
3776				'length'  => $this->get_col_length( $table, $column ),
3777			),
3778		);
3779
3780		$data = $this->strip_invalid_text( $data );
3781		if ( is_wp_error( $data ) ) {
3782			return $data;
3783		}
3784
3785		return $data[ $column ]['value'];
3786	}
3787
3788	/**
3789	 * Finds the first table name referenced in a query.
3790	 *
3791	 * @since 4.2.0
3792	 *
3793	 * @param string $query The query to search.
3794	 * @return string|false The table name found, or false if a table couldn't be found.
3795	 */
3796	protected function get_table_from_query( $query ) {
3797		// Remove characters that can legally trail the table name.
3798		$query = rtrim( $query, ';/-#' );
3799
3800		// Allow (select...) union [...] style queries. Use the first query's table name.
3801		$query = ltrim( $query, "\r\n\t (" );
3802
3803		// Strip everything between parentheses except nested selects.
3804		$query = preg_replace( '/\((?!\s*select)[^(]*?\)/is', '()', $query );
3805
3806		// Strip any leading SET STATEMENT statements.
3807		$query = preg_replace( '/^SET STATEMENT.+?\sFOR\s+/is', '', $query );
3808
3809		// Quickly match most common queries.
3810		if ( preg_match(
3811			'/^\s*(?:'
3812				. 'SELECT.*?\s+FROM'
3813				. '|INSERT(?:\s+LOW_PRIORITY|\s+DELAYED|\s+HIGH_PRIORITY)?(?:\s+IGNORE)?(?:\s+INTO)?'
3814				. '|REPLACE(?:\s+LOW_PRIORITY|\s+DELAYED)?(?:\s+INTO)?'
3815				. '|UPDATE(?:\s+LOW_PRIORITY)?(?:\s+IGNORE)?'
3816				. '|DELETE(?:\s+LOW_PRIORITY|\s+QUICK|\s+IGNORE)*(?:.+?FROM)?'
3817			. ')\s+((?:[0-9a-zA-Z$_.`-]|[\xC2-\xDF][\x80-\xBF])+)/is',
3818			$query,
3819			$maybe
3820		) ) {
3821			return str_replace( '`', '', $maybe[1] );
3822		}
3823
3824		// SHOW TABLE STATUS and SHOW TABLES WHERE Name = 'wp_posts'
3825		if ( preg_match( '/^\s*SHOW\s+(?:TABLE\s+STATUS|(?:FULL\s+)?TABLES).+WHERE\s+Name\s*=\s*("|\')((?:[0-9a-zA-Z$_.-]|[\xC2-\xDF][\x80-\xBF])+)\\1/is', $query, $maybe ) ) {
3826			return $maybe[2];
3827		}
3828
3829		/*
3830		 * SHOW TABLE STATUS LIKE and SHOW TABLES LIKE 'wp\_123\_%'
3831		 * This quoted LIKE operand seldom holds a full table name.
3832		 * It is usually a pattern for matching a prefix so we just
3833		 * strip the trailing % and unescape the _ to get 'wp_123_'
3834		 * which drop-ins can use for routing these SQL statements.
3835		 */
3836		if ( preg_match( '/^\s*SHOW\s+(?:TABLE\s+STATUS|(?:FULL\s+)?TABLES)\s+(?:WHERE\s+Name\s+)?LIKE\s*("|\')((?:[\\\\0-9a-zA-Z$_.-]|[\xC2-\xDF][\x80-\xBF])+)%?\\1/is', $query, $maybe ) ) {
3837			return str_replace( '\\_', '_', $maybe[2] );
3838		}
3839
3840		// Big pattern for the rest of the table-related queries.
3841		if ( preg_match(
3842			'/^\s*(?:'
3843				. '(?:EXPLAIN\s+(?:EXTENDED\s+)?)?SELECT.*?\s+FROM'
3844				. '|DESCRIBE|DESC|EXPLAIN|HANDLER'
3845				. '|(?:LOCK|UNLOCK)\s+TABLE(?:S)?'
3846				. '|(?:RENAME|OPTIMIZE|BACKUP|RESTORE|CHECK|CHECKSUM|ANALYZE|REPAIR).*\s+TABLE'
3847				. '|TRUNCATE(?:\s+TABLE)?'
3848				. '|CREATE(?:\s+TEMPORARY)?\s+TABLE(?:\s+IF\s+NOT\s+EXISTS)?'
3849				. '|ALTER(?:\s+IGNORE)?\s+TABLE'
3850				. '|DROP\s+TABLE(?:\s+IF\s+EXISTS)?'
3851				. '|CREATE(?:\s+\w+)?\s+INDEX.*\s+ON'
3852				. '|DROP\s+INDEX.*\s+ON'
3853				. '|LOAD\s+DATA.*INFILE.*INTO\s+TABLE'
3854				. '|(?:GRANT|REVOKE).*ON\s+TABLE'
3855				. '|SHOW\s+(?:.*FROM|.*TABLE)'
3856			. ')\s+\(*\s*((?:[0-9a-zA-Z$_.`-]|[\xC2-\xDF][\x80-\xBF])+)\s*\)*/is',
3857			$query,
3858			$maybe
3859		) ) {
3860			return str_replace( '`', '', $maybe[1] );
3861		}
3862
3863		return false;
3864	}
3865
3866	/**
3867	 * Loads the column metadata from the last query.
3868	 *
3869	 * @since 3.5.0
3870	 */
3871	protected function load_col_info() {
3872		if ( $this->col_info ) {
3873			return;
3874		}
3875
3876		$num_fields = mysqli_num_fields( $this->result );
3877
3878		for ( $i = 0; $i < $num_fields; $i++ ) {
3879			$this->col_info[ $i ] = mysqli_fetch_field( $this->result );
3880		}
3881	}
3882
3883	/**
3884	 * Retrieves column metadata from the last query.
3885	 *
3886	 * @since 0.71
3887	 *
3888	 * @param string $info_type  Optional. Possible values include 'name', 'table', 'def', 'max_length',
3889	 *                           'not_null', 'primary_key', 'multiple_key', 'unique_key', 'numeric',
3890	 *                           'blob', 'type', 'unsigned', 'zerofill'. Default 'name'.
3891	 * @param int    $col_offset Optional. 0: col name. 1: which table the col's in. 2: col's max length.
3892	 *                           3: if the col is numeric. 4: col's type. Default -1.
3893	 * @return mixed Column results.
3894	 */
3895	public function get_col_info( $info_type = 'name', $col_offset = -1 ) {
3896		$this->load_col_info();
3897
3898		if ( $this->col_info ) {
3899			if ( -1 === $col_offset ) {
3900				$i         = 0;
3901				$new_array = array();
3902				foreach ( (array) $this->col_info as $col ) {
3903					$new_array[ $i ] = $col->{$info_type};
3904					++$i;
3905				}
3906				return $new_array;
3907			} else {
3908				return $this->col_info[ $col_offset ]->{$info_type};
3909			}
3910		}
3911	}
3912
3913	/**
3914	 * Starts the timer, for debugging purposes.
3915	 *
3916	 * @since 1.5.0
3917	 *
3918	 * @return true
3919	 */
3920	public function timer_start() {
3921		$this->time_start = microtime( true );
3922		return true;
3923	}
3924
3925	/**
3926	 * Stops the debugging timer.
3927	 *
3928	 * @since 1.5.0
3929	 *
3930	 * @return float Total time spent on the query, in seconds.
3931	 */
3932	public function timer_stop() {
3933		return ( microtime( true ) - $this->time_start );
3934	}
3935
3936	/**
3937	 * Wraps errors in a nice header and footer and dies.
3938	 *
3939	 * Will not die if wpdb::$show_errors is false.
3940	 *
3941	 * @since 1.5.0
3942	 *
3943	 * @param string $message    The error message.
3944	 * @param string $error_code Optional. A computer-readable string to identify the error.
3945	 *                           Default '500'.
3946	 * @return void|false Void if the showing of errors is enabled, false if disabled.
3947	 */
3948	public function bail( $message, $error_code = '500' ) {
3949		if ( $this->show_errors ) {
3950			$error = '';
3951
3952			if ( $this->dbh instanceof mysqli ) {
3953				$error = mysqli_error( $this->dbh );
3954			} elseif ( mysqli_connect_errno() ) {
3955				$error = mysqli_connect_error();
3956			}
3957
3958			if ( $error ) {
3959				$message = '<p><code>' . $error . "</code></p>\n" . $message;
3960			}
3961
3962			wp_die( $message );
3963		} else {
3964			if ( class_exists( 'WP_Error', false ) ) {
3965				$this->error = new WP_Error( $error_code, $message );
3966			} else {
3967				$this->error = $message;
3968			}
3969
3970			return false;
3971		}
3972	}
3973
3974	/**
3975	 * Closes the current database connection.
3976	 *
3977	 * @since 4.5.0
3978	 *
3979	 * @return bool True if the connection was successfully closed,
3980	 *              false if it wasn't, or if the connection doesn't exist.
3981	 */
3982	public function close() {
3983		if ( ! $this->dbh ) {
3984			return false;
3985		}
3986
3987		$closed = mysqli_close( $this->dbh );
3988
3989		if ( $closed ) {
3990			$this->dbh           = null;
3991			$this->ready         = false;
3992			$this->has_connected = false;
3993		}
3994
3995		return $closed;
3996	}
3997
3998	/**
3999	 * Determines whether the database server is at least the required minimum version.
4000	 *
4001	 * @since 2.5.0
4002	 *
4003	 * @global string $required_mysql_version The minimum required MySQL version string.
4004	 * @return void|WP_Error
4005	 */
4006	public function check_database_version() {
4007		global $required_mysql_version;
4008		$wp_version = wp_get_wp_version();
4009
4010		// Make sure the server has the required MySQL version.
4011		if ( version_compare( $this->db_version(), $required_mysql_version, '<' ) ) {
4012			/* translators: 1: WordPress version number, 2: Minimum required MySQL version number. */
4013			return new WP_Error( 'database_version', sprintf( __( '<strong>Error:</strong> WordPress %1$s requires MySQL %2$s or higher' ), $wp_version, $required_mysql_version ) );
4014		}
4015	}
4016
4017	/**
4018	 * Determines whether the database supports collation.
4019	 *
4020	 * Called when WordPress is generating the table scheme.
4021	 *
4022	 * Use `wpdb::has_cap( 'collation' )`.
4023	 *
4024	 * @since 2.5.0
4025	 * @deprecated 3.5.0 Use wpdb::has_cap()
4026	 *
4027	 * @return bool True if collation is supported, false if not.
4028	 */
4029	public function supports_collation() {
4030		_deprecated_function( __FUNCTION__, '3.5.0', 'wpdb::has_cap( \'collation\' )' );
4031		return $this->has_cap( 'collation' );
4032	}
4033
4034	/**
4035	 * Retrieves the database character collate.
4036	 *
4037	 * @since 3.5.0
4038	 *
4039	 * @return string The database character collate.
4040	 */
4041	public function get_charset_collate() {
4042		$charset_collate = '';
4043
4044		if ( ! empty( $this->charset ) ) {
4045			$charset_collate = "DEFAULT CHARACTER SET $this->charset";
4046		}
4047		if ( ! empty( $this->collate ) ) {
4048			$charset_collate .= " COLLATE $this->collate";
4049		}
4050
4051		return $charset_collate;
4052	}
4053
4054	/**
4055	 * Determines whether the database or WPDB supports a particular feature.
4056	 *
4057	 * Capability sniffs for the database server and current version of WPDB.
4058	 *
4059	 * Database sniffs are based on the version of the database server in use.
4060	 *
4061	 * WPDB sniffs are added as new features are introduced to allow theme and plugin
4062	 * developers to determine feature support. This is to account for drop-ins which may
4063	 * introduce feature support at a different time to WordPress.
4064	 *
4065	 * @since 2.7.0
4066	 * @since 4.1.0 Added support for the 'utf8mb4' feature.
4067	 * @since 4.6.0 Added support for the 'utf8mb4_520' feature.
4068	 * @since 6.2.0 Added support for the 'identifier_placeholders' feature.
4069	 * @since 6.6.0 The `utf8mb4` feature now always returns true.
4070	 *
4071	 * @see wpdb::db_version()
4072	 *
4073	 * @param string $db_cap The feature to check for. Accepts 'collation', 'group_concat',
4074	 *                       'subqueries', 'set_charset', 'utf8mb4', 'utf8mb4_520',
4075	 *                       or 'identifier_placeholders'.
4076	 * @return bool True when the database feature is supported, false otherwise.
4077	 */
4078	public function has_cap( $db_cap ) {
4079		$db_version     = $this->db_version();
4080		$db_server_info = $this->db_server_info();
4081
4082		/*
4083		 * Account for MariaDB version being prefixed with '5.5.5-' on older PHP versions.
4084		 *
4085		 * Note: str_contains() is not used here, as this file can be included
4086		 * directly outside of WordPress core, e.g. by HyperDB, in which case
4087		 * the polyfills from wp-includes/compat.php are not loaded.
4088		 */
4089		if ( '5.5.5' === $db_version && false !== strpos( $db_server_info, 'MariaDB' )
4090			&& PHP_VERSION_ID < 80016 // PHP 8.0.15 or older.
4091		) {
4092			// Strip the '5.5.5-' prefix and set the version to the correct value.
4093			$db_server_info = preg_replace( '/^5\.5\.5-(.*)/', '$1', $db_server_info );
4094			$db_version     = preg_replace( '/[^0-9.].*/', '', $db_server_info );
4095		}
4096
4097		switch ( strtolower( $db_cap ) ) {
4098			case 'collation':    // @since 2.5.0
4099			case 'group_concat': // @since 2.7.0
4100			case 'subqueries':   // @since 2.7.0
4101				return version_compare( $db_version, '4.1', '>=' );
4102			case 'set_charset':
4103				return version_compare( $db_version, '5.0.7', '>=' );
4104			case 'utf8mb4':      // @since 4.1.0
4105				return true;
4106			case 'utf8mb4_520': // @since 4.6.0
4107				return version_compare( $db_version, '5.6', '>=' );
4108			case 'identifier_placeholders': // @since 6.2.0
4109				/*
4110				 * As of WordPress 6.2, wpdb::prepare() supports identifiers via '%i',
4111				 * e.g. table/field names.
4112				 */
4113				return true;
4114		}
4115
4116		return false;
4117	}
4118
4119	/**
4120	 * Retrieves a comma-separated list of the names of the functions that called wpdb.
4121	 *
4122	 * @since 2.5.0
4123	 *
4124	 * @return string Comma-separated list of the calling functions.
4125	 */
4126	public function get_caller() {
4127		return wp_debug_backtrace_summary( __CLASS__ );
4128	}
4129
4130	/**
4131	 * Retrieves the database server version number.
4132	 *
4133	 * @since 2.7.0
4134	 *
4135	 * @return string|null Version number on success, null on failure.
4136	 */
4137	public function db_version() {
4138		return preg_replace( '/[^0-9.].*/', '', $this->db_server_info() );
4139	}
4140
4141	/**
4142	 * Returns the raw version string of the database server.
4143	 *
4144	 * @since 5.5.0
4145	 *
4146	 * @return string Database server version as a string.
4147	 */
4148	public function db_server_info() {
4149		return mysqli_get_server_info( $this->dbh );
4150	}
4151}
4152