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Ticket #41956: wp-db.php

File wp-db.php, 93.7 KB (added by LeonN1960, 8 years ago)
my db file with last_errno

Line
1	<?php
2	/**
3	* WordPress DB 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	*/
15	define( 'EZSQL_VERSION', 'WP1.25' );
16
17	/**
18	* @since 0.71
19	*/
20	define( 'OBJECT', 'OBJECT' );
21	define( 'object', 'OBJECT' ); // Back compat.
22
23	/**
24	* @since 2.5.0
25	*/
26	define( 'OBJECT_K', 'OBJECT_K' );
27
28	/**
29	* @since 0.71
30	*/
31	define( 'ARRAY_A', 'ARRAY_A' );
32
33	/**
34	* @since 0.71
35	*/
36	define( 'ARRAY_N', 'ARRAY_N' );
37
38	/**
39	* WordPress Database Access Abstraction Object
40	*
41	* It is possible to replace this class with your own
42	* by setting the $wpdb global variable in wp-content/db.php
43	* file to your class. The wpdb class will still be included,
44	* so you can extend it or simply use your own.
45	*
46	* @link https://codex.wordpress.org/Function_Reference/wpdb_Class
47	*
48	* @package WordPress
49	* @subpackage Database
50	* @since 0.71
51	*/
52	class wpdb {
53
54	/**
55	* Whether to show SQL/DB errors.
56	*
57	* Default behavior is to show errors if both WP_DEBUG and WP_DEBUG_DISPLAY
58	* evaluated to true.
59	*
60	* @since 0.71
61	* @access private
62	* @var bool
63	*/
64	var $show_errors = false;
65
66	/**
67	* Whether to suppress errors during the DB bootstrapping.
68	*
69	* @access private
70	* @since 2.5.0
71	* @var bool
72	*/
73	var $suppress_errors = false;
74
75	/**
76	* The last error during query.
77	*
78	* @since 2.5.0
79	* @var string
80	*/
81	public $last_error = '';
82	public $last_errno = '';
83
84	/**
85	* Amount of queries made
86	*
87	* @since 1.2.0
88	* @access public
89	* @var int
90	*/
91	public $num_queries = 0;
92
93	/**
94	* Count of rows returned by previous query
95	*
96	* @since 0.71
97	* @access public
98	* @var int
99	*/
100	public $num_rows = 0;
101
102	/**
103	* Count of affected rows by previous query
104	*
105	* @since 0.71
106	* @access private
107	* @var int
108	*/
109	var $rows_affected = 0;
110
111	/**
112	* The ID generated for an AUTO_INCREMENT column by the previous query (usually INSERT).
113	*
114	* @since 0.71
115	* @access public
116	* @var int
117	*/
118	public $insert_id = 0;
119
120	/**
121	* Last query made
122	*
123	* @since 0.71
124	* @access private
125	* @var array
126	*/
127	var $last_query;
128
129	/**
130	* Results of the last query made
131	*
132	* @since 0.71
133	* @access private
134	* @var array\|null
135	*/
136	var $last_result;
137
138	/**
139	* MySQL result, which is either a resource or boolean.
140	*
141	* @since 0.71
142	* @access protected
143	* @var mixed
144	*/
145	protected $result;
146
147	/**
148	* Cached column info, for sanity checking data before inserting
149	*
150	* @since 4.2.0
151	* @access protected
152	* @var array
153	*/
154	protected $col_meta = array();
155
156	/**
157	* Calculated character sets on tables
158	*
159	* @since 4.2.0
160	* @access protected
161	* @var array
162	*/
163	protected $table_charset = array();
164
165	/**
166	* Whether text fields in the current query need to be sanity checked.
167	*
168	* @since 4.2.0
169	* @access protected
170	* @var bool
171	*/
172	protected $check_current_query = true;
173
174	/**
175	* Flag to ensure we don't run into recursion problems when checking the collation.
176	*
177	* @since 4.2.0
178	* @access private
179	* @see wpdb::check_safe_collation()
180	* @var bool
181	*/
182	private $checking_collation = false;
183
184	/**
185	* Saved info on the table column
186	*
187	* @since 0.71
188	* @access protected
189	* @var array
190	*/
191	protected $col_info;
192
193	/**
194	* Saved queries that were executed
195	*
196	* @since 1.5.0
197	* @access private
198	* @var array
199	*/
200	var $queries;
201
202	/**
203	* The number of times to retry reconnecting before dying.
204	*
205	* @since 3.9.0
206	* @access protected
207	* @see wpdb::check_connection()
208	* @var int
209	*/
210	protected $reconnect_retries = 5;
211
212	/**
213	* WordPress table prefix
214	*
215	* You can set this to have multiple WordPress installations
216	* in a single database. The second reason is for possible
217	* security precautions.
218	*
219	* @since 2.5.0
220	* @access public
221	* @var string
222	*/
223	public $prefix = '';
224
225	/**
226	* WordPress base table prefix.
227	*
228	* @since 3.0.0
229	* @access public
230	* @var string
231	*/
232	public $base_prefix;
233
234	/**
235	* Whether the database queries are ready to start executing.
236	*
237	* @since 2.3.2
238	* @access private
239	* @var bool
240	*/
241	var $ready = false;
242
243	/**
244	* Blog ID.
245	*
246	* @since 3.0.0
247	* @access public
248	* @var int
249	*/
250	public $blogid = 0;
251
252	/**
253	* Site ID.
254	*
255	* @since 3.0.0
256	* @access public
257	* @var int
258	*/
259	public $siteid = 0;
260
261	/**
262	* List of WordPress per-blog tables
263	*
264	* @since 2.5.0
265	* @access private
266	* @see wpdb::tables()
267	* @var array
268	*/
269	var $tables = array( 'posts', 'comments', 'links', 'options', 'postmeta',
270	'terms', 'term_taxonomy', 'term_relationships', 'termmeta', 'commentmeta' );
271
272	/**
273	* List of deprecated WordPress tables
274	*
275	* categories, post2cat, and link2cat were deprecated in 2.3.0, db version 5539
276	*
277	* @since 2.9.0
278	* @access private
279	* @see wpdb::tables()
280	* @var array
281	*/
282	var $old_tables = array( 'categories', 'post2cat', 'link2cat' );
283
284	/**
285	* List of WordPress global tables
286	*
287	* @since 3.0.0
288	* @access private
289	* @see wpdb::tables()
290	* @var array
291	*/
292	var $global_tables = array( 'users', 'usermeta' );
293
294	/**
295	* List of Multisite global tables
296	*
297	* @since 3.0.0
298	* @access private
299	* @see wpdb::tables()
300	* @var array
301	*/
302	var $ms_global_tables = array( 'blogs', 'signups', 'site', 'sitemeta',
303	'sitecategories', 'registration_log', 'blog_versions' );
304
305	/**
306	* WordPress Comments table
307	*
308	* @since 1.5.0
309	* @access public
310	* @var string
311	*/
312	public $comments;
313
314	/**
315	* WordPress Comment Metadata table
316	*
317	* @since 2.9.0
318	* @access public
319	* @var string
320	*/
321	public $commentmeta;
322
323	/**
324	* WordPress Links table
325	*
326	* @since 1.5.0
327	* @access public
328	* @var string
329	*/
330	public $links;
331
332	/**
333	* WordPress Options table
334	*
335	* @since 1.5.0
336	* @access public
337	* @var string
338	*/
339	public $options;
340
341	/**
342	* WordPress Post Metadata table
343	*
344	* @since 1.5.0
345	* @access public
346	* @var string
347	*/
348	public $postmeta;
349
350	/**
351	* WordPress Posts table
352	*
353	* @since 1.5.0
354	* @access public
355	* @var string
356	*/
357	public $posts;
358
359	/**
360	* WordPress Terms table
361	*
362	* @since 2.3.0
363	* @access public
364	* @var string
365	*/
366	public $terms;
367
368	/**
369	* WordPress Term Relationships table
370	*
371	* @since 2.3.0
372	* @access public
373	* @var string
374	*/
375	public $term_relationships;
376
377	/**
378	* WordPress Term Taxonomy table
379	*
380	* @since 2.3.0
381	* @access public
382	* @var string
383	*/
384	public $term_taxonomy;
385
386	/**
387	* WordPress Term Meta table.
388	*
389	* @since 4.4.0
390	* @access public
391	* @var string
392	*/
393	public $termmeta;
394
395	//
396	// Global and Multisite tables
397	//
398
399	/**
400	* WordPress User Metadata table
401	*
402	* @since 2.3.0
403	* @access public
404	* @var string
405	*/
406	public $usermeta;
407
408	/**
409	* WordPress Users table
410	*
411	* @since 1.5.0
412	* @access public
413	* @var string
414	*/
415	public $users;
416
417	/**
418	* Multisite Blogs table
419	*
420	* @since 3.0.0
421	* @access public
422	* @var string
423	*/
424	public $blogs;
425
426	/**
427	* Multisite Blog Versions table
428	*
429	* @since 3.0.0
430	* @access public
431	* @var string
432	*/
433	public $blog_versions;
434
435	/**
436	* Multisite Registration Log table
437	*
438	* @since 3.0.0
439	* @access public
440	* @var string
441	*/
442	public $registration_log;
443
444	/**
445	* Multisite Signups table
446	*
447	* @since 3.0.0
448	* @access public
449	* @var string
450	*/
451	public $signups;
452
453	/**
454	* Multisite Sites table
455	*
456	* @since 3.0.0
457	* @access public
458	* @var string
459	*/
460	public $site;
461
462	/**
463	* Multisite Sitewide Terms table
464	*
465	* @since 3.0.0
466	* @access public
467	* @var string
468	*/
469	public $sitecategories;
470
471	/**
472	* Multisite Site Metadata table
473	*
474	* @since 3.0.0
475	* @access public
476	* @var string
477	*/
478	public $sitemeta;
479
480	/**
481	* Format specifiers for DB columns. Columns not listed here default to %s. Initialized during WP load.
482	*
483	* Keys are column names, values are format types: 'ID' => '%d'
484	*
485	* @since 2.8.0
486	* @see wpdb::prepare()
487	* @see wpdb::insert()
488	* @see wpdb::update()
489	* @see wpdb::delete()
490	* @see wp_set_wpdb_vars()
491	* @access public
492	* @var array
493	*/
494	public $field_types = array();
495
496	/**
497	* Database table columns charset
498	*
499	* @since 2.2.0
500	* @access public
501	* @var string
502	*/
503	public $charset;
504
505	/**
506	* Database table columns collate
507	*
508	* @since 2.2.0
509	* @access public
510	* @var string
511	*/
512	public $collate;
513
514	/**
515	* Database Username
516	*
517	* @since 2.9.0
518	* @access protected
519	* @var string
520	*/
521	protected $dbuser;
522
523	/**
524	* Database Password
525	*
526	* @since 3.1.0
527	* @access protected
528	* @var string
529	*/
530	protected $dbpassword;
531
532	/**
533	* Database Name
534	*
535	* @since 3.1.0
536	* @access protected
537	* @var string
538	*/
539	protected $dbname;
540
541	/**
542	* Database Host
543	*
544	* @since 3.1.0
545	* @access protected
546	* @var string
547	*/
548	protected $dbhost;
549
550	/**
551	* Database Handle
552	*
553	* @since 0.71
554	* @access protected
555	* @var string
556	*/
557	protected $dbh;
558
559	/**
560	* A textual description of the last query/get_row/get_var call
561	*
562	* @since 3.0.0
563	* @access public
564	* @var string
565	*/
566	public $func_call;
567
568	/**
569	* Whether MySQL is used as the database engine.
570	*
571	* Set in WPDB::db_connect() to true, by default. This is used when checking
572	* against the required MySQL version for WordPress. Normally, a replacement
573	* database drop-in (db.php) will skip these checks, but setting this to true
574	* will force the checks to occur.
575	*
576	* @since 3.3.0
577	* @access public
578	* @var bool
579	*/
580	public $is_mysql = null;
581
582	/**
583	* A list of incompatible SQL modes.
584	*
585	* @since 3.9.0
586	* @access protected
587	* @var array
588	*/
589	protected $incompatible_modes = array( 'NO_ZERO_DATE', 'ONLY_FULL_GROUP_BY',
590	'STRICT_TRANS_TABLES', 'STRICT_ALL_TABLES', 'TRADITIONAL' );
591
592	/**
593	* Whether to use mysqli over mysql.
594	*
595	* @since 3.9.0
596	* @access private
597	* @var bool
598	*/
599	private $use_mysqli = false;
600
601	/**
602	* Whether we've managed to successfully connect at some point
603	*
604	* @since 3.9.0
605	* @access private
606	* @var bool
607	*/
608	private $has_connected = false;
609
610	/**
611	* Connects to the database server and selects a database
612	*
613	* PHP5 style constructor for compatibility with PHP5. Does
614	* the actual setting up of the class properties and connection
615	* to the database.
616	*
617	* @link https://core.trac.wordpress.org/ticket/3354
618	* @since 2.0.8
619	*
620	* @global string $wp_version
621	*
622	* @param string $dbuser MySQL database user
623	* @param string $dbpassword MySQL database password
624	* @param string $dbname MySQL database name
625	* @param string $dbhost MySQL database host
626	*/
627	public function __construct( $dbuser, $dbpassword, $dbname, $dbhost ) {
628	register_shutdown_function( array( $this, '__destruct' ) );
629
630	if ( WP_DEBUG && WP_DEBUG_DISPLAY )
631	$this->show_errors();
632
633	/* Use ext/mysqli if it exists and:
634	* - WP_USE_EXT_MYSQL is defined as false, or
635	* - We are a development version of WordPress, or
636	* - We are running PHP 5.5 or greater, or
637	* - ext/mysql is not loaded.
638	*/
639	if ( function_exists( 'mysqli_connect' ) ) {
640	if ( defined( 'WP_USE_EXT_MYSQL' ) ) {
641	$this->use_mysqli = ! WP_USE_EXT_MYSQL;
642	} elseif ( version_compare( phpversion(), '5.5', '>=' ) \|\| ! function_exists( 'mysql_connect' ) ) {
643	$this->use_mysqli = true;
644	} elseif ( false !== strpos( $GLOBALS['wp_version'], '-' ) ) {
645	$this->use_mysqli = true;
646	}
647	}
648
649	$this->dbuser = $dbuser;
650	$this->dbpassword = $dbpassword;
651	$this->dbname = $dbname;
652	$this->dbhost = $dbhost;
653
654	// wp-config.php creation will manually connect when ready.
655	if ( defined( 'WP_SETUP_CONFIG' ) ) {
656	return;
657	}
658
659	$this->db_connect();
660	}
661
662	/**
663	* PHP5 style destructor and will run when database object is destroyed.
664	*
665	* @see wpdb::__construct()
666	* @since 2.0.8
667	* @return true
668	*/
669	public function __destruct() {
670	return true;
671	}
672
673	/**
674	* Makes private properties readable for backward compatibility.
675	*
676	* @since 3.5.0
677	*
678	* @param string $name The private member to get, and optionally process
679	* @return mixed The private member
680	*/
681	public function __get( $name ) {
682	if ( 'col_info' === $name )
683	$this->load_col_info();
684
685	return $this->$name;
686	}
687
688	/**
689	* Makes private properties settable for backward compatibility.
690	*
691	* @since 3.5.0
692	*
693	* @param string $name The private member to set
694	* @param mixed $value The value to set
695	*/
696	public function __set( $name, $value ) {
697	$protected_members = array(
698	'col_meta',
699	'table_charset',
700	'check_current_query',
701	);
702	if ( in_array( $name, $protected_members, true ) ) {
703	return;
704	}
705	$this->$name = $value;
706	}
707
708	/**
709	* Makes private properties check-able for backward compatibility.
710	*
711	* @since 3.5.0
712	*
713	* @param string $name The private member to check
714	*
715	* @return bool If the member is set or not
716	*/
717	public function __isset( $name ) {
718	return isset( $this->$name );
719	}
720
721	/**
722	* Makes private properties un-settable for backward compatibility.
723	*
724	* @since 3.5.0
725	*
726	* @param string $name The private member to unset
727	*/
728	public function __unset( $name ) {
729	unset( $this->$name );
730	}
731
732	/**
733	* Set $this->charset and $this->collate
734	*
735	* @since 3.1.0
736	*/
737	public function init_charset() {
738	$charset = '';
739	$collate = '';
740
741	if ( function_exists('is_multisite') && is_multisite() ) {
742	$charset = 'utf8';
743	if ( defined( 'DB_COLLATE' ) && DB_COLLATE ) {
744	$collate = DB_COLLATE;
745	} else {
746	$collate = 'utf8_general_ci';
747	}
748	} elseif ( defined( 'DB_COLLATE' ) ) {
749	$collate = DB_COLLATE;
750	}
751
752	if ( defined( 'DB_CHARSET' ) ) {
753	$charset = DB_CHARSET;
754	}
755
756	$charset_collate = $this->determine_charset( $charset, $collate );
757
758	$this->charset = $charset_collate['charset'];
759	$this->collate = $charset_collate['collate'];
760	}
761
762	/**
763	* Determines the best charset and collation to use given a charset and collation.
764	*
765	* For example, when able, utf8mb4 should be used instead of utf8.
766	*
767	* @since 4.6.0
768	* @access public
769	*
770	* @param string $charset The character set to check.
771	* @param string $collate The collation to check.
772	* @return array The most appropriate character set and collation to use.
773	*/
774	public function determine_charset( $charset, $collate ) {
775	if ( ( $this->use_mysqli && ! ( $this->dbh instanceof mysqli ) ) \|\| empty( $this->dbh ) ) {
776	return compact( 'charset', 'collate' );
777	}
778
779	if ( 'utf8' === $charset && $this->has_cap( 'utf8mb4' ) ) {
780	$charset = 'utf8mb4';
781	}
782
783	if ( 'utf8mb4' === $charset && ! $this->has_cap( 'utf8mb4' ) ) {
784	$charset = 'utf8';
785	$collate = str_replace( 'utf8mb4_', 'utf8_', $collate );
786	}
787
788	if ( 'utf8mb4' === $charset ) {
789	// _general_ is outdated, so we can upgrade it to _unicode_, instead.
790	if ( ! $collate \|\| 'utf8_general_ci' === $collate ) {
791	$collate = 'utf8mb4_unicode_ci';
792	} else {
793	$collate = str_replace( 'utf8_', 'utf8mb4_', $collate );
794	}
795	}
796
797	// _unicode_520_ is a better collation, we should use that when it's available.
798	if ( $this->has_cap( 'utf8mb4_520' ) && 'utf8mb4_unicode_ci' === $collate ) {
799	$collate = 'utf8mb4_unicode_520_ci';
800	}
801
802	return compact( 'charset', 'collate' );
803	}
804
805	/**
806	* Sets the connection's character set.
807	*
808	* @since 3.1.0
809	*
810	* @param resource $dbh The resource given by mysql_connect
811	* @param string $charset Optional. The character set. Default null.
812	* @param string $collate Optional. The collation. Default null.
813	*/
814	public function set_charset( $dbh, $charset = null, $collate = null ) {
815	if ( ! isset( $charset ) )
816	$charset = $this->charset;
817	if ( ! isset( $collate ) )
818	$collate = $this->collate;
819	if ( $this->has_cap( 'collation' ) && ! empty( $charset ) ) {
820	$set_charset_succeeded = true;
821
822	if ( $this->use_mysqli ) {
823	if ( function_exists( 'mysqli_set_charset' ) && $this->has_cap( 'set_charset' ) ) {
824	$set_charset_succeeded = mysqli_set_charset( $dbh, $charset );
825	}
826
827	if ( $set_charset_succeeded ) {
828	$query = $this->prepare( 'SET NAMES %s', $charset );
829	if ( ! empty( $collate ) )
830	$query .= $this->prepare( ' COLLATE %s', $collate );
831	mysqli_query( $dbh, $query );
832	}
833	} else {
834	if ( function_exists( 'mysql_set_charset' ) && $this->has_cap( 'set_charset' ) ) {
835	$set_charset_succeeded = mysql_set_charset( $charset, $dbh );
836	}
837	if ( $set_charset_succeeded ) {
838	$query = $this->prepare( 'SET NAMES %s', $charset );
839	if ( ! empty( $collate ) )
840	$query .= $this->prepare( ' COLLATE %s', $collate );
841	mysql_query( $query, $dbh );
842	}
843	}
844	}
845	}
846
847	/**
848	* Change the current SQL mode, and ensure its WordPress compatibility.
849	*
850	* If no modes are passed, it will ensure the current MySQL server
851	* modes are compatible.
852	*
853	* @since 3.9.0
854	*
855	* @param array $modes Optional. A list of SQL modes to set.
856	*/
857	public function set_sql_mode( $modes = array() ) {
858	if ( empty( $modes ) ) {
859	if ( $this->use_mysqli ) {
860	$res = mysqli_query( $this->dbh, 'SELECT @@SESSION.sql_mode' );
861	} else {
862	$res = mysql_query( 'SELECT @@SESSION.sql_mode', $this->dbh );
863	}
864
865	if ( empty( $res ) ) {
866	return;
867	}
868
869	if ( $this->use_mysqli ) {
870	$modes_array = mysqli_fetch_array( $res );
871	if ( empty( $modes_array[0] ) ) {
872	return;
873	}
874	$modes_str = $modes_array[0];
875	} else {
876	$modes_str = mysql_result( $res, 0 );
877	}
878
879	if ( empty( $modes_str ) ) {
880	return;
881	}
882
883	$modes = explode( ',', $modes_str );
884	}
885
886	$modes = array_change_key_case( $modes, CASE_UPPER );
887
888	/**
889	* Filters the list of incompatible SQL modes to exclude.
890	*
891	* @since 3.9.0
892	*
893	* @param array $incompatible_modes An array of incompatible modes.
894	*/
895	$incompatible_modes = (array) apply_filters( 'incompatible_sql_modes', $this->incompatible_modes );
896
897	foreach ( $modes as $i => $mode ) {
898	if ( in_array( $mode, $incompatible_modes ) ) {
899	unset( $modes[ $i ] );
900	}
901	}
902
903	$modes_str = implode( ',', $modes );
904
905	if ( $this->use_mysqli ) {
906	mysqli_query( $this->dbh, "SET SESSION sql_mode='$modes_str'" );
907	} else {
908	mysql_query( "SET SESSION sql_mode='$modes_str'", $this->dbh );
909	}
910	}
911
912	/**
913	* Sets the table prefix for the WordPress tables.
914	*
915	* @since 2.5.0
916	*
917	* @param string $prefix Alphanumeric name for the new prefix.
918	* @param bool $set_table_names Optional. Whether the table names, e.g. wpdb::$posts, should be updated or not.
919	* @return string\|WP_Error Old prefix or WP_Error on error
920	*/
921	public function set_prefix( $prefix, $set_table_names = true ) {
922
923	if ( preg_match( '\|[^a-z0-9_]\|i', $prefix ) )
924	return new WP_Error('invalid_db_prefix', 'Invalid database prefix' );
925
926	$old_prefix = is_multisite() ? '' : $prefix;
927
928	if ( isset( $this->base_prefix ) )
929	$old_prefix = $this->base_prefix;
930
931	$this->base_prefix = $prefix;
932
933	if ( $set_table_names ) {
934	foreach ( $this->tables( 'global' ) as $table => $prefixed_table )
935	$this->$table = $prefixed_table;
936
937	if ( is_multisite() && empty( $this->blogid ) )
938	return $old_prefix;
939
940	$this->prefix = $this->get_blog_prefix();
941
942	foreach ( $this->tables( 'blog' ) as $table => $prefixed_table )
943	$this->$table = $prefixed_table;
944
945	foreach ( $this->tables( 'old' ) as $table => $prefixed_table )
946	$this->$table = $prefixed_table;
947	}
948	return $old_prefix;
949	}
950
951	/**
952	* Sets blog id.
953	*
954	* @since 3.0.0
955	* @access public
956	*
957	* @param int $blog_id
958	* @param int $site_id Optional.
959	* @return int previous blog id
960	*/
961	public function set_blog_id( $blog_id, $site_id = 0 ) {
962	if ( ! empty( $site_id ) )
963	$this->siteid = $site_id;
964
965	$old_blog_id = $this->blogid;
966	$this->blogid = $blog_id;
967
968	$this->prefix = $this->get_blog_prefix();
969
970	foreach ( $this->tables( 'blog' ) as $table => $prefixed_table )
971	$this->$table = $prefixed_table;
972
973	foreach ( $this->tables( 'old' ) as $table => $prefixed_table )
974	$this->$table = $prefixed_table;
975
976	return $old_blog_id;
977	}
978
979	/**
980	* Gets blog prefix.
981	*
982	* @since 3.0.0
983	* @param int $blog_id Optional.
984	* @return string Blog prefix.
985	*/
986	public function get_blog_prefix( $blog_id = null ) {
987	if ( is_multisite() ) {
988	if ( null === $blog_id )
989	$blog_id = $this->blogid;
990	$blog_id = (int) $blog_id;
991	if ( defined( 'MULTISITE' ) && ( 0 == $blog_id \|\| 1 == $blog_id ) )
992	return $this->base_prefix;
993	else
994	return $this->base_prefix . $blog_id . '_';
995	} else {
996	return $this->base_prefix;
997	}
998	}
999
1000	/**
1001	* Returns an array of WordPress tables.
1002	*
1003	* Also allows for the CUSTOM_USER_TABLE and CUSTOM_USER_META_TABLE to
1004	* override the WordPress users and usermeta tables that would otherwise
1005	* be determined by the prefix.
1006	*
1007	* The scope argument can take one of the following:
1008	*
1009	* 'all' - returns 'all' and 'global' tables. No old tables are returned.
1010	* 'blog' - returns the blog-level tables for the queried blog.
1011	* 'global' - returns the global tables for the installation, returning multisite tables only if running multisite.
1012	* 'ms_global' - returns the multisite global tables, regardless if current installation is multisite.
1013	* 'old' - returns tables which are deprecated.
1014	*
1015	* @since 3.0.0
1016	* @uses wpdb::$tables
1017	* @uses wpdb::$old_tables
1018	* @uses wpdb::$global_tables
1019	* @uses wpdb::$ms_global_tables
1020	*
1021	* @param string $scope Optional. Can be all, global, ms_global, blog, or old tables. Defaults to all.
1022	* @param bool $prefix Optional. Whether to include table prefixes. Default true. If blog
1023	* prefix is requested, then the custom users and usermeta tables will be mapped.
1024	* @param int $blog_id Optional. The blog_id to prefix. Defaults to wpdb::$blogid. Used only when prefix is requested.
1025	* @return array Table names. When a prefix is requested, the key is the unprefixed table name.
1026	*/
1027	public function tables( $scope = 'all', $prefix = true, $blog_id = 0 ) {
1028	switch ( $scope ) {
1029	case 'all' :
1030	$tables = array_merge( $this->global_tables, $this->tables );
1031	if ( is_multisite() )
1032	$tables = array_merge( $tables, $this->ms_global_tables );
1033	break;
1034	case 'blog' :
1035	$tables = $this->tables;
1036	break;
1037	case 'global' :
1038	$tables = $this->global_tables;
1039	if ( is_multisite() )
1040	$tables = array_merge( $tables, $this->ms_global_tables );
1041	break;
1042	case 'ms_global' :
1043	$tables = $this->ms_global_tables;
1044	break;
1045	case 'old' :
1046	$tables = $this->old_tables;
1047	break;
1048	default :
1049	return array();
1050	}
1051
1052	if ( $prefix ) {
1053	if ( ! $blog_id )
1054	$blog_id = $this->blogid;
1055	$blog_prefix = $this->get_blog_prefix( $blog_id );
1056	$base_prefix = $this->base_prefix;
1057	$global_tables = array_merge( $this->global_tables, $this->ms_global_tables );
1058	foreach ( $tables as $k => $table ) {
1059	if ( in_array( $table, $global_tables ) )
1060	$tables[ $table ] = $base_prefix . $table;
1061	else
1062	$tables[ $table ] = $blog_prefix . $table;
1063	unset( $tables[ $k ] );
1064	}
1065
1066	if ( isset( $tables['users'] ) && defined( 'CUSTOM_USER_TABLE' ) )
1067	$tables['users'] = CUSTOM_USER_TABLE;
1068
1069	if ( isset( $tables['usermeta'] ) && defined( 'CUSTOM_USER_META_TABLE' ) )
1070	$tables['usermeta'] = CUSTOM_USER_META_TABLE;
1071	}
1072
1073	return $tables;
1074	}
1075
1076	/**
1077	* Selects a database using the current database connection.
1078	*
1079	* The database name will be changed based on the current database
1080	* connection. On failure, the execution will bail and display an DB error.
1081	*
1082	* @since 0.71
1083	*
1084	* @param string $db MySQL database name
1085	* @param resource\|null $dbh Optional link identifier.
1086	*/
1087	public function select( $db, $dbh = null ) {
1088	if ( is_null($dbh) )
1089	$dbh = $this->dbh;
1090
1091	if ( $this->use_mysqli ) {
1092	$success = mysqli_select_db( $dbh, $db );
1093	} else {
1094	$success = mysql_select_db( $db, $dbh );
1095	}
1096	if ( ! $success ) {
1097	$this->ready = false;
1098	if ( ! did_action( 'template_redirect' ) ) {
1099	wp_load_translations_early();
1100
1101	$message = '<h1>' . __( 'Can’t select database' ) . "</h1>\n";
1102
1103	$message .= '<p>' . sprintf(
1104	/* translators: %s: database name */
1105	__( 'We were able to connect to the database server (which means your username and password is okay) but not able to select the %s database.' ),
1106	'<code>' . htmlspecialchars( $db, ENT_QUOTES ) . '</code>'
1107	) . "</p>\n";
1108
1109	$message .= "<ul>\n";
1110	$message .= '<li>' . __( 'Are you sure it exists?' ) . "</li>\n";
1111
1112	$message .= '<li>' . sprintf(
1113	/* translators: 1: database user, 2: database name */
1114	__( 'Does the user %1$s have permission to use the %2$s database?' ),
1115	'<code>' . htmlspecialchars( $this->dbuser, ENT_QUOTES ) . '</code>',
1116	'<code>' . htmlspecialchars( $db, ENT_QUOTES ) . '</code>'
1117	) . "</li>\n";
1118
1119	$message .= '<li>' . sprintf(
1120	/* translators: %s: database name */
1121	__( 'On some systems the name of your database is prefixed with your username, so it would be like <code>username_%1$s</code>. Could that be the problem?' ),
1122	htmlspecialchars( $db, ENT_QUOTES )
1123	). "</li>\n";
1124
1125	$message .= "</ul>\n";
1126
1127	$message .= '<p>' . sprintf(
1128	/* translators: %s: support forums URL */
1129	__( 'If you don’t 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>.' ),
1130	__( 'https://wordpress.org/support/' )
1131	) . "</p>\n";
1132
1133	$this->bail( $message, 'db_select_fail' );
1134	}
1135	}
1136	}
1137
1138	/**
1139	* Do not use, deprecated.
1140	*
1141	* Use esc_sql() or wpdb::prepare() instead.
1142	*
1143	* @since 2.8.0
1144	* @deprecated 3.6.0 Use wpdb::prepare()
1145	* @see wpdb::prepare
1146	* @see esc_sql()
1147	* @access private
1148	*
1149	* @param string $string
1150	* @return string
1151	*/
1152	function _weak_escape( $string ) {
1153	if ( func_num_args() === 1 && function_exists( '_deprecated_function' ) )
1154	_deprecated_function( __METHOD__, '3.6.0', 'wpdb::prepare() or esc_sql()' );
1155	return addslashes( $string );
1156	}
1157
1158	/**
1159	* Real escape, using mysqli_real_escape_string() or mysql_real_escape_string()
1160	*
1161	* @see mysqli_real_escape_string()
1162	* @see mysql_real_escape_string()
1163	* @since 2.8.0
1164	* @access private
1165	*
1166	* @param string $string to escape
1167	* @return string escaped
1168	*/
1169	function _real_escape( $string ) {
1170	if ( $this->dbh ) {
1171	if ( $this->use_mysqli ) {
1172	return mysqli_real_escape_string( $this->dbh, $string );
1173	} else {
1174	return mysql_real_escape_string( $string, $this->dbh );
1175	}
1176	}
1177
1178	$class = get_class( $this );
1179	if ( function_exists( '__' ) ) {
1180	/* translators: %s: database access abstraction class, usually wpdb or a class extending wpdb */
1181	_doing_it_wrong( $class, sprintf( __( '%s must set a database connection for use with escaping.' ), $class ), '3.6.0' );
1182	} else {
1183	_doing_it_wrong( $class, sprintf( '%s must set a database connection for use with escaping.', $class ), '3.6.0' );
1184	}
1185	return addslashes( $string );
1186	}
1187
1188	/**
1189	* Escape data. Works on arrays.
1190	*
1191	* @uses wpdb::_real_escape()
1192	* @since 2.8.0
1193	* @access public
1194	*
1195	* @param string\|array $data
1196	* @return string\|array escaped
1197	*/
1198	public function _escape( $data ) {
1199	if ( is_array( $data ) ) {
1200	foreach ( $data as $k => $v ) {
1201	if ( is_array( $v ) ) {
1202	$data[$k] = $this->_escape( $v );
1203	} else {
1204	$data[$k] = $this->_real_escape( $v );
1205	}
1206	}
1207	} else {
1208	$data = $this->_real_escape( $data );
1209	}
1210
1211	return $data;
1212	}
1213
1214	/**
1215	* Do not use, deprecated.
1216	*
1217	* Use esc_sql() or wpdb::prepare() instead.
1218	*
1219	* @since 0.71
1220	* @deprecated 3.6.0 Use wpdb::prepare()
1221	* @see wpdb::prepare()
1222	* @see esc_sql()
1223	*
1224	* @param mixed $data
1225	* @return mixed
1226	*/
1227	public function escape( $data ) {
1228	if ( func_num_args() === 1 && function_exists( '_deprecated_function' ) )
1229	_deprecated_function( __METHOD__, '3.6.0', 'wpdb::prepare() or esc_sql()' );
1230	if ( is_array( $data ) ) {
1231	foreach ( $data as $k => $v ) {
1232	if ( is_array( $v ) )
1233	$data[$k] = $this->escape( $v, 'recursive' );
1234	else
1235	$data[$k] = $this->_weak_escape( $v, 'internal' );
1236	}
1237	} else {
1238	$data = $this->_weak_escape( $data, 'internal' );
1239	}
1240
1241	return $data;
1242	}
1243
1244	/**
1245	* Escapes content by reference for insertion into the database, for security
1246	*
1247	* @uses wpdb::_real_escape()
1248	*
1249	* @since 2.3.0
1250	*
1251	* @param string $string to escape
1252	*/
1253	public function escape_by_ref( &$string ) {
1254	if ( ! is_float( $string ) )
1255	$string = $this->_real_escape( $string );
1256	}
1257
1258	/**
1259	* Prepares a SQL query for safe execution. Uses sprintf()-like syntax.
1260	*
1261	* The following directives can be used in the query format string:
1262	* %d (integer)
1263	* %f (float)
1264	* %s (string)
1265	* %% (literal percentage sign - no argument needed)
1266	*
1267	* All of %d, %f, and %s are to be left unquoted in the query string and they need an argument passed for them.
1268	* Literals (%) as parts of the query must be properly written as %%.
1269	*
1270	* This function only supports a small subset of the sprintf syntax; it only supports %d (integer), %f (float), and %s (string).
1271	* Does not support sign, padding, alignment, width or precision specifiers.
1272	* Does not support argument numbering/swapping.
1273	*
1274	* May be called like {@link https://secure.php.net/sprintf sprintf()} or like {@link https://secure.php.net/vsprintf vsprintf()}.
1275	*
1276	* Both %d and %s should be left unquoted in the query string.
1277	*
1278	* $wpdb->prepare( "SELECT * FROM `table` WHERE `column` = %s AND `field` = %d", 'foo', 1337 );
1279	* $wpdb->prepare( "SELECT DATE_FORMAT(`field`, '%%c') FROM `table` WHERE `column` = %s", 'foo' );
1280	*
1281	* @link https://secure.php.net/sprintf Description of syntax.
1282	* @since 2.3.0
1283	*
1284	* @param string $query Query statement with sprintf()-like placeholders
1285	* @param array\|mixed $args The array of variables to substitute into the query's placeholders if being called like
1286	* {@link https://secure.php.net/vsprintf vsprintf()}, or the first variable to substitute into the query's placeholders if
1287	* being called like {@link https://secure.php.net/sprintf sprintf()}.
1288	* @param mixed $args,... further variables to substitute into the query's placeholders if being called like
1289	* {@link https://secure.php.net/sprintf sprintf()}.
1290	* @return string\|void Sanitized query string, if there is a query to prepare.
1291	*/
1292	public function prepare( $query, $args ) {
1293	if ( is_null( $query ) )
1294	return;
1295
1296	// This is not meant to be foolproof -- but it will catch obviously incorrect usage.
1297	if ( strpos( $query, '%' ) === false ) {
1298	_doing_it_wrong( 'wpdb::prepare', sprintf( __( 'The query argument of %s must have a placeholder.' ), 'wpdb::prepare()' ), '3.9.0' );
1299	}
1300
1301	$args = func_get_args();
1302	array_shift( $args );
1303
1304	// If args were passed as an array (as in vsprintf), move them up
1305	if ( is_array( $args[0] ) && count( $args ) == 1 ) {
1306	$args = $args[0];
1307	}
1308
1309	foreach ( $args as $arg ) {
1310	if ( ! is_scalar( $arg ) && ! is_null( $arg ) ) {
1311	_doing_it_wrong( 'wpdb::prepare', sprintf( 'Unsupported value type (%s).', gettype( $arg ) ), '4.8.2' );
1312	}
1313	}
1314
1315	$query = str_replace( "'%s'", '%s', $query ); // in case someone mistakenly already singlequoted it
1316	$query = str_replace( '"%s"', '%s', $query ); // doublequote unquoting
1317	$query = preg_replace( '\|(?<!%)%f\|' , '%F', $query ); // Force floats to be locale unaware
1318	$query = preg_replace( '\|(?<!%)%s\|', "'%s'", $query ); // quote the strings, avoiding escaped strings like %%s
1319	$query = preg_replace( '/%(?:%\|$\|([^dsF]))/', '%%\\1', $query ); // escape any unescaped percents
1320	array_walk( $args, array( $this, 'escape_by_ref' ) );
1321	return @vsprintf( $query, $args );
1322	}
1323
1324	/**
1325	* First half of escaping for LIKE special characters % and _ before preparing for MySQL.
1326	*
1327	* Use this only before wpdb::prepare() or esc_sql(). Reversing the order is very bad for security.
1328	*
1329	* Example Prepared Statement:
1330	*
1331	* $wild = '%';
1332	* $find = 'only 43% of planets';
1333	* $like = $wild . $wpdb->esc_like( $find ) . $wild;
1334	* $sql = $wpdb->prepare( "SELECT * FROM $wpdb->posts WHERE post_content LIKE '%s'", $like );
1335	*
1336	* Example Escape Chain:
1337	*
1338	* $sql = esc_sql( $wpdb->esc_like( $input ) );
1339	*
1340	* @since 4.0.0
1341	* @access public
1342	*
1343	* @param string $text The raw text to be escaped. The input typed by the user should have no
1344	* extra or deleted slashes.
1345	* @return string Text in the form of a LIKE phrase. The output is not SQL safe. Call $wpdb::prepare()
1346	* or real_escape next.
1347	*/
1348	public function esc_like( $text ) {
1349	return addcslashes( $text, '_%\\' );
1350	}
1351
1352	/**
1353	* Print SQL/DB error.
1354	*
1355	* @since 0.71
1356	* @global array $EZSQL_ERROR Stores error information of query and error string
1357	*
1358	* @param string $str The error to display
1359	* @return false\|void False if the showing of errors is disabled.
1360	*/
1361	public function print_error( $str = '' ) {
1362	global $EZSQL_ERROR;
1363
1364	if ( !$str ) {
1365	if ( $this->use_mysqli ) {
1366	$str = mysqli_error( $this->dbh );
1367	} else {
1368	$str = mysql_error( $this->dbh );
1369	}
1370	}
1371	$EZSQL_ERROR[] = array( 'query' => $this->last_query, 'error_str' => $str );
1372
1373	if ( $this->suppress_errors )
1374	return false;
1375
1376	wp_load_translations_early();
1377
1378	if ( $caller = $this->get_caller() ) {
1379	/* translators: 1: Database error message, 2: SQL query, 3: Name of the calling function */
1380	$error_str = sprintf( __( 'WordPress database error %1$s for query %2$s made by %3$s' ), $str, $this->last_query, $caller );
1381	} else {
1382	/* translators: 1: Database error message, 2: SQL query */
1383	$error_str = sprintf( __( 'WordPress database error %1$s for query %2$s' ), $str, $this->last_query );
1384	}
1385
1386	error_log( $error_str );
1387
1388	// Are we showing errors?
1389	if ( ! $this->show_errors )
1390	return false;
1391
1392	// If there is an error then take note of it
1393	if ( is_multisite() ) {
1394	$msg = sprintf(
1395	"%s [%s]\n%s\n",
1396	__( 'WordPress database error:' ),
1397	$str,
1398	$this->last_query
1399	);
1400
1401	if ( defined( 'ERRORLOGFILE' ) ) {
1402	error_log( $msg, 3, ERRORLOGFILE );
1403	}
1404	if ( defined( 'DIEONDBERROR' ) ) {
1405	wp_die( $msg );
1406	}
1407	} else {
1408	$str = htmlspecialchars( $str, ENT_QUOTES );
1409	$query = htmlspecialchars( $this->last_query, ENT_QUOTES );
1410
1411	printf(
1412	'<div id="error"><p class="wpdberror"><strong>%s</strong> [%s]<br /><code>%s</code></p></div>',
1413	__( 'WordPress database error:' ),
1414	$str,
1415	$query
1416	);
1417	}
1418	}
1419
1420	/**
1421	* Enables showing of database errors.
1422	*
1423	* This function should be used only to enable showing of errors.
1424	* wpdb::hide_errors() should be used instead for hiding of errors. However,
1425	* this function can be used to enable and disable showing of database
1426	* errors.
1427	*
1428	* @since 0.71
1429	* @see wpdb::hide_errors()
1430	*
1431	* @param bool $show Whether to show or hide errors
1432	* @return bool Old value for showing errors.
1433	*/
1434	public function show_errors( $show = true ) {
1435	$errors = $this->show_errors;
1436	$this->show_errors = $show;
1437	return $errors;
1438	}
1439
1440	/**
1441	* Disables showing of database errors.
1442	*
1443	* By default database errors are not shown.
1444	*
1445	* @since 0.71
1446	* @see wpdb::show_errors()
1447	*
1448	* @return bool Whether showing of errors was active
1449	*/
1450	public function hide_errors() {
1451	$show = $this->show_errors;
1452	$this->show_errors = false;
1453	return $show;
1454	}
1455
1456	/**
1457	* Whether to suppress database errors.
1458	*
1459	* By default database errors are suppressed, with a simple
1460	* call to this function they can be enabled.
1461	*
1462	* @since 2.5.0
1463	* @see wpdb::hide_errors()
1464	* @param bool $suppress Optional. New value. Defaults to true.
1465	* @return bool Old value
1466	*/
1467	public function suppress_errors( $suppress = true ) {
1468	$errors = $this->suppress_errors;
1469	$this->suppress_errors = (bool) $suppress;
1470	return $errors;
1471	}
1472
1473	/**
1474	* Kill cached query results.
1475	*
1476	* @since 0.71
1477	*/
1478	public function flush() {
1479	$this->last_result = array();
1480	$this->col_info = null;
1481	$this->last_query = null;
1482	$this->rows_affected = $this->num_rows = 0;
1483	$this->last_error = '';
1484	$this->last_errno = 0;
1485
1486	if ( $this->use_mysqli && $this->result instanceof mysqli_result ) {
1487	mysqli_free_result( $this->result );
1488	$this->result = null;
1489
1490	// Sanity check before using the handle
1491	if ( empty( $this->dbh ) \|\| !( $this->dbh instanceof mysqli ) ) {
1492	return;
1493	}
1494
1495	// Clear out any results from a multi-query
1496	while ( mysqli_more_results( $this->dbh ) ) {
1497	mysqli_next_result( $this->dbh );
1498	}
1499	} elseif ( is_resource( $this->result ) ) {
1500	mysql_free_result( $this->result );
1501	}
1502	}
1503
1504	/**
1505	* Connect to and select database.
1506	*
1507	* If $allow_bail is false, the lack of database connection will need
1508	* to be handled manually.
1509	*
1510	* @since 3.0.0
1511	* @since 3.9.0 $allow_bail parameter added.
1512	*
1513	* @param bool $allow_bail Optional. Allows the function to bail. Default true.
1514	* @return bool True with a successful connection, false on failure.
1515	*/
1516	public function db_connect( $allow_bail = true ) {
1517	$this->is_mysql = true;
1518
1519	/*
1520	* Deprecated in 3.9+ when using MySQLi. No equivalent
1521	* $new_link parameter exists for mysqli_* functions.
1522	*/
1523	$new_link = defined( 'MYSQL_NEW_LINK' ) ? MYSQL_NEW_LINK : true;
1524	$client_flags = defined( 'MYSQL_CLIENT_FLAGS' ) ? MYSQL_CLIENT_FLAGS : 0;
1525
1526	if ( $this->use_mysqli ) {
1527	$this->dbh = mysqli_init();
1528
1529	// mysqli_real_connect doesn't support the host param including a port or socket
1530	// like mysql_connect does. This duplicates how mysql_connect detects a port and/or socket file.
1531	$port = null;
1532	$socket = null;
1533	$host = $this->dbhost;
1534	$port_or_socket = strstr( $host, ':' );
1535	if ( ! empty( $port_or_socket ) ) {
1536	$host = substr( $host, 0, strpos( $host, ':' ) );
1537	$port_or_socket = substr( $port_or_socket, 1 );
1538	if ( 0 !== strpos( $port_or_socket, '/' ) ) {
1539	$port = intval( $port_or_socket );
1540	$maybe_socket = strstr( $port_or_socket, ':' );
1541	if ( ! empty( $maybe_socket ) ) {
1542	$socket = substr( $maybe_socket, 1 );
1543	}
1544	} else {
1545	$socket = $port_or_socket;
1546	}
1547	}
1548
1549	if ( WP_DEBUG ) {
1550	mysqli_real_connect( $this->dbh, $host, $this->dbuser, $this->dbpassword, null, $port, $socket, $client_flags );
1551	} else {
1552	@mysqli_real_connect( $this->dbh, $host, $this->dbuser, $this->dbpassword, null, $port, $socket, $client_flags );
1553	}
1554
1555	if ( $this->dbh->connect_errno ) {
1556	$this->dbh = null;
1557
1558	/* It's possible ext/mysqli is misconfigured. Fall back to ext/mysql if:
1559	* - We haven't previously connected, and
1560	* - WP_USE_EXT_MYSQL isn't set to false, and
1561	* - ext/mysql is loaded.
1562	*/
1563	$attempt_fallback = true;
1564
1565	if ( $this->has_connected ) {
1566	$attempt_fallback = false;
1567	} elseif ( defined( 'WP_USE_EXT_MYSQL' ) && ! WP_USE_EXT_MYSQL ) {
1568	$attempt_fallback = false;
1569	} elseif ( ! function_exists( 'mysql_connect' ) ) {
1570	$attempt_fallback = false;
1571	}
1572
1573	if ( $attempt_fallback ) {
1574	$this->use_mysqli = false;
1575	return $this->db_connect( $allow_bail );
1576	}
1577	}
1578	} else {
1579	if ( WP_DEBUG ) {
1580	$this->dbh = mysql_connect( $this->dbhost, $this->dbuser, $this->dbpassword, $new_link, $client_flags );
1581	} else {
1582	$this->dbh = @mysql_connect( $this->dbhost, $this->dbuser, $this->dbpassword, $new_link, $client_flags );
1583	}
1584	}
1585
1586	if ( ! $this->dbh && $allow_bail ) {
1587	wp_load_translations_early();
1588
1589	// Load custom DB error template, if present.
1590	if ( file_exists( WP_CONTENT_DIR . '/db-error.php' ) ) {
1591	require_once( WP_CONTENT_DIR . '/db-error.php' );
1592	die();
1593	}
1594
1595	$message = '<h1>' . __( 'Error establishing a database connection' ) . "</h1>\n";
1596
1597	$message .= '<p>' . sprintf(
1598	/* translators: 1: wp-config.php. 2: database host */
1599	__( 'This either means that the username and password information in your %1$s file is incorrect or we can’t contact the database server at %2$s. This could mean your host’s database server is down.' ),
1600	'<code>wp-config.php</code>',
1601	'<code>' . htmlspecialchars( $this->dbhost, ENT_QUOTES ) . '</code>'
1602	) . "</p>\n";
1603
1604	$message .= "<ul>\n";
1605	$message .= '<li>' . __( 'Are you sure you have the correct username and password?' ) . "</li>\n";
1606	$message .= '<li>' . __( 'Are you sure that you have typed the correct hostname?' ) . "</li>\n";
1607	$message .= '<li>' . __( 'Are you sure that the database server is running?' ) . "</li>\n";
1608	$message .= "</ul>\n";
1609
1610	$message .= '<p>' . sprintf(
1611	/* translators: %s: support forums URL */
1612	__( 'If you’re 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>.' ),
1613	__( 'https://wordpress.org/support/' )
1614	) . "</p>\n";
1615
1616	$this->bail( $message, 'db_connect_fail' );
1617
1618	return false;
1619	} elseif ( $this->dbh ) {
1620	if ( ! $this->has_connected ) {
1621	$this->init_charset();
1622	}
1623
1624	$this->has_connected = true;
1625
1626	$this->set_charset( $this->dbh );
1627
1628	$this->ready = true;
1629	$this->set_sql_mode();
1630	$this->select( $this->dbname, $this->dbh );
1631
1632	return true;
1633	}
1634
1635	return false;
1636	}
1637
1638	/**
1639	* Checks that the connection to the database is still up. If not, try to reconnect.
1640	*
1641	* If this function is unable to reconnect, it will forcibly die, or if after the
1642	* the {@see 'template_redirect'} hook has been fired, return false instead.
1643	*
1644	* If $allow_bail is false, the lack of database connection will need
1645	* to be handled manually.
1646	*
1647	* @since 3.9.0
1648	*
1649	* @param bool $allow_bail Optional. Allows the function to bail. Default true.
1650	* @return bool\|void True if the connection is up.
1651	*/
1652	public function check_connection( $allow_bail = true ) {
1653	if ( $this->use_mysqli ) {
1654	if ( ! empty( $this->dbh ) && mysqli_ping( $this->dbh ) ) {
1655	return true;
1656	}
1657	} else {
1658	if ( ! empty( $this->dbh ) && mysql_ping( $this->dbh ) ) {
1659	return true;
1660	}
1661	}
1662
1663	$error_reporting = false;
1664
1665	// Disable warnings, as we don't want to see a multitude of "unable to connect" messages
1666	if ( WP_DEBUG ) {
1667	$error_reporting = error_reporting();
1668	error_reporting( $error_reporting & ~E_WARNING );
1669	}
1670
1671	for ( $tries = 1; $tries <= $this->reconnect_retries; $tries++ ) {
1672	// On the last try, re-enable warnings. We want to see a single instance of the
1673	// "unable to connect" message on the bail() screen, if it appears.
1674	if ( $this->reconnect_retries === $tries && WP_DEBUG ) {
1675	error_reporting( $error_reporting );
1676	}
1677
1678	if ( $this->db_connect( false ) ) {
1679	if ( $error_reporting ) {
1680	error_reporting( $error_reporting );
1681	}
1682
1683	return true;
1684	}
1685
1686	sleep( 1 );
1687	}
1688
1689	// If template_redirect has already happened, it's too late for wp_die()/dead_db().
1690	// Let's just return and hope for the best.
1691	if ( did_action( 'template_redirect' ) ) {
1692	return false;
1693	}
1694
1695	if ( ! $allow_bail ) {
1696	return false;
1697	}
1698
1699	wp_load_translations_early();
1700
1701	$message = '<h1>' . __( 'Error reconnecting to the database' ) . "</h1>\n";
1702
1703	$message .= '<p>' . sprintf(
1704	/* translators: %s: database host */
1705	__( 'This means that we lost contact with the database server at %s. This could mean your host’s database server is down.' ),
1706	'<code>' . htmlspecialchars( $this->dbhost, ENT_QUOTES ) . '</code>'
1707	) . "</p>\n";
1708
1709	$message .= "<ul>\n";
1710	$message .= '<li>' . __( 'Are you sure that the database server is running?' ) . "</li>\n";
1711	$message .= '<li>' . __( 'Are you sure that the database server is not under particularly heavy load?' ) . "</li>\n";
1712	$message .= "</ul>\n";
1713
1714	$message .= '<p>' . sprintf(
1715	/* translators: %s: support forums URL */
1716	__( 'If you’re 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>.' ),
1717	__( 'https://wordpress.org/support/' )
1718	) . "</p>\n";
1719
1720	// We weren't able to reconnect, so we better bail.
1721	$this->bail( $message, 'db_connect_fail' );
1722
1723	// Call dead_db() if bail didn't die, because this database is no more. It has ceased to be (at least temporarily).
1724	dead_db();
1725	}
1726
1727	/**
1728	* Perform a MySQL database query, using current database connection.
1729	*
1730	* More information can be found on the codex page.
1731	*
1732	* @since 0.71
1733	*
1734	* @param string $query Database query
1735	* @return int\|false Number of rows affected/selected or false on error
1736	*/
1737	public function query( $query ) {
1738	if ( ! $this->ready ) {
1739	$this->check_current_query = true;
1740	return false;
1741	}
1742
1743	/**
1744	* Filters the database query.
1745	*
1746	* Some queries are made before the plugins have been loaded,
1747	* and thus cannot be filtered with this method.
1748	*
1749	* @since 2.1.0
1750	*
1751	* @param string $query Database query.
1752	*/
1753	$query = apply_filters( 'query', $query );
1754
1755	$this->flush();
1756
1757	// Log how the function was called
1758	$this->func_call = "\$db->query(\"$query\")";
1759
1760	// If we're writing to the database, make sure the query will write safely.
1761	if ( $this->check_current_query && ! $this->check_ascii( $query ) ) {
1762	$stripped_query = $this->strip_invalid_text_from_query( $query );
1763	// strip_invalid_text_from_query() can perform queries, so we need
1764	// to flush again, just to make sure everything is clear.
1765	$this->flush();
1766	if ( $stripped_query !== $query ) {
1767	$this->insert_id = 0;
1768	return false;
1769	}
1770	}
1771
1772	$this->check_current_query = true;
1773
1774	// Keep track of the last query for debug.
1775	$this->last_query = $query;
1776
1777	$this->_do_query( $query );
1778
1779	// MySQL server has gone away, try to reconnect.
1780	$mysql_errno = 0;
1781	if ( ! empty( $this->dbh ) ) {
1782	if ( $this->use_mysqli ) {
1783	if ( $this->dbh instanceof mysqli ) {
1784	$mysql_errno = mysqli_errno( $this->dbh );
1785	} else {
1786	// $dbh is defined, but isn't a real connection.
1787	// Something has gone horribly wrong, let's try a reconnect.
1788	$mysql_errno = 2006;
1789	}
1790	} else {
1791	if ( is_resource( $this->dbh ) ) {
1792	$mysql_errno = mysql_errno( $this->dbh );
1793	} else {
1794	$mysql_errno = 2006;
1795	}
1796	}
1797	}
1798
1799	if ( empty( $this->dbh ) \|\| 2006 == $mysql_errno ) {
1800	if ( $this->check_connection() ) {
1801	$this->_do_query( $query );
1802	} else {
1803	$this->insert_id = 0;
1804	return false;
1805	}
1806	}
1807
1808	// If there is an error then take note of it.
1809	if ( $this->use_mysqli ) {
1810	$this->last_errno = mysqli_errno( $this->dbh );
1811	if ( $this->dbh instanceof mysqli ) {
1812	$this->last_error = mysqli_error( $this->dbh );
1813	} else {
1814	$this->last_error = __( 'Unable to retrieve the error message from MySQL' );
1815	}
1816	} else {
1817	if ( is_resource( $this->dbh ) ) {
1818	$this->last_error = mysql_error( $this->dbh );
1819	} else {
1820	$this->last_error = __( 'Unable to retrieve the error message from MySQL' );
1821	}
1822	}
1823
1824	if ( $this->last_error ) {
1825	// Clear insert_id on a subsequent failed insert.
1826	if ( $this->insert_id && preg_match( '/^\s*(insert\|replace)\s/i', $query ) )
1827	$this->insert_id = 0;
1828
1829	$this->print_error();
1830	return false;
1831	}
1832
1833	if ( preg_match( '/^\s*(create\|alter\|truncate\|drop)\s/i', $query ) ) {
1834	$return_val = $this->result;
1835	} elseif ( preg_match( '/^\s*(insert\|delete\|update\|replace)\s/i', $query ) ) {
1836	if ( $this->use_mysqli ) {
1837	$this->rows_affected = mysqli_affected_rows( $this->dbh );
1838	} else {
1839	$this->rows_affected = mysql_affected_rows( $this->dbh );
1840	}
1841	// Take note of the insert_id
1842	if ( preg_match( '/^\s*(insert\|replace)\s/i', $query ) ) {
1843	if ( $this->use_mysqli ) {
1844	$this->insert_id = mysqli_insert_id( $this->dbh );
1845	} else {
1846	$this->insert_id = mysql_insert_id( $this->dbh );
1847	}
1848	}
1849	// Return number of rows affected
1850	$return_val = $this->rows_affected;
1851	} else {
1852	$num_rows = 0;
1853	if ( $this->use_mysqli && $this->result instanceof mysqli_result ) {
1854	while ( $row = mysqli_fetch_object( $this->result ) ) {
1855	$this->last_result[$num_rows] = $row;
1856	$num_rows++;
1857	}
1858	} elseif ( is_resource( $this->result ) ) {
1859	while ( $row = mysql_fetch_object( $this->result ) ) {
1860	$this->last_result[$num_rows] = $row;
1861	$num_rows++;
1862	}
1863	}
1864
1865	// Log number of rows the query returned
1866	// and return number of rows selected
1867	$this->num_rows = $num_rows;
1868	$return_val = $num_rows;
1869	}
1870
1871	return $return_val;
1872	}
1873
1874	/**
1875	* Internal function to perform the mysql_query() call.
1876	*
1877	* @since 3.9.0
1878	*
1879	* @access private
1880	* @see wpdb::query()
1881	*
1882	* @param string $query The query to run.
1883	*/
1884	private function _do_query( $query ) {
1885	if ( defined( 'SAVEQUERIES' ) && SAVEQUERIES ) {
1886	$this->timer_start();
1887	}
1888
1889	if ( ! empty( $this->dbh ) && $this->use_mysqli ) {
1890	$this->result = mysqli_query( $this->dbh, $query );
1891	} elseif ( ! empty( $this->dbh ) ) {
1892	$this->result = mysql_query( $query, $this->dbh );
1893	}
1894	$this->num_queries++;
1895
1896	if ( defined( 'SAVEQUERIES' ) && SAVEQUERIES ) {
1897	$this->queries[] = array( $query, $this->timer_stop(), $this->get_caller() );
1898	}
1899	}
1900
1901	/**
1902	* Insert a row into a table.
1903	*
1904	* wpdb::insert( 'table', array( 'column' => 'foo', 'field' => 'bar' ) )
1905	* wpdb::insert( 'table', array( 'column' => 'foo', 'field' => 1337 ), array( '%s', '%d' ) )
1906	*
1907	* @since 2.5.0
1908	* @see wpdb::prepare()
1909	* @see wpdb::$field_types
1910	* @see wp_set_wpdb_vars()
1911	*
1912	* @param string $table Table name
1913	* @param array $data Data to insert (in column => value pairs).
1914	* Both $data columns and $data values should be "raw" (neither should be SQL escaped).
1915	* Sending a null value will cause the column to be set to NULL - the corresponding format is ignored in this case.
1916	* @param array\|string $format Optional. An array of formats to be mapped to each of the value in $data.
1917	* If string, that format will be used for all of the values in $data.
1918	* A format is one of '%d', '%f', '%s' (integer, float, string).
1919	* If omitted, all values in $data will be treated as strings unless otherwise specified in wpdb::$field_types.
1920	* @return int\|false The number of rows inserted, or false on error.
1921	*/
1922	public function insert( $table, $data, $format = null ) {
1923	return $this->_insert_replace_helper( $table, $data, $format, 'INSERT' );
1924	}
1925
1926	/**
1927	* Replace a row into a table.
1928	*
1929	* wpdb::replace( 'table', array( 'column' => 'foo', 'field' => 'bar' ) )
1930	* wpdb::replace( 'table', array( 'column' => 'foo', 'field' => 1337 ), array( '%s', '%d' ) )
1931	*
1932	* @since 3.0.0
1933	* @see wpdb::prepare()
1934	* @see wpdb::$field_types
1935	* @see wp_set_wpdb_vars()
1936	*
1937	* @param string $table Table name
1938	* @param array $data Data to insert (in column => value pairs).
1939	* Both $data columns and $data values should be "raw" (neither should be SQL escaped).
1940	* Sending a null value will cause the column to be set to NULL - the corresponding format is ignored in this case.
1941	* @param array\|string $format Optional. An array of formats to be mapped to each of the value in $data.
1942	* If string, that format will be used for all of the values in $data.
1943	* A format is one of '%d', '%f', '%s' (integer, float, string).
1944	* If omitted, all values in $data will be treated as strings unless otherwise specified in wpdb::$field_types.
1945	* @return int\|false The number of rows affected, or false on error.
1946	*/
1947	public function replace( $table, $data, $format = null ) {
1948	return $this->_insert_replace_helper( $table, $data, $format, 'REPLACE' );
1949	}
1950
1951	/**
1952	* Helper function for insert and replace.
1953	*
1954	* Runs an insert or replace query based on $type argument.
1955	*
1956	* @access private
1957	* @since 3.0.0
1958	* @see wpdb::prepare()
1959	* @see wpdb::$field_types
1960	* @see wp_set_wpdb_vars()
1961	*
1962	* @param string $table Table name
1963	* @param array $data Data to insert (in column => value pairs).
1964	* Both $data columns and $data values should be "raw" (neither should be SQL escaped).
1965	* Sending a null value will cause the column to be set to NULL - the corresponding format is ignored in this case.
1966	* @param array\|string $format Optional. An array of formats to be mapped to each of the value in $data.
1967	* If string, that format will be used for all of the values in $data.
1968	* A format is one of '%d', '%f', '%s' (integer, float, string).
1969	* If omitted, all values in $data will be treated as strings unless otherwise specified in wpdb::$field_types.
1970	* @param string $type Optional. What type of operation is this? INSERT or REPLACE. Defaults to INSERT.
1971	* @return int\|false The number of rows affected, or false on error.
1972	*/
1973	function _insert_replace_helper( $table, $data, $format = null, $type = 'INSERT' ) {
1974	$this->insert_id = 0;
1975
1976	if ( ! in_array( strtoupper( $type ), array( 'REPLACE', 'INSERT' ) ) ) {
1977	return false;
1978	}
1979
1980	$data = $this->process_fields( $table, $data, $format );
1981	if ( false === $data ) {
1982	return false;
1983	}
1984
1985	$formats = $values = array();
1986	foreach ( $data as $value ) {
1987	if ( is_null( $value['value'] ) ) {
1988	$formats[] = 'NULL';
1989	continue;
1990	}
1991
1992	$formats[] = $value['format'];
1993	$values[] = $value['value'];
1994	}
1995
1996	$fields = '`' . implode( '`, `', array_keys( $data ) ) . '`';
1997	$formats = implode( ', ', $formats );
1998
1999	$sql = "$type INTO `$table` ($fields) VALUES ($formats)";
2000
2001	$this->check_current_query = false;
2002	return $this->query( $this->prepare( $sql, $values ) );
2003	}
2004
2005	/**
2006	* Update a row in the table
2007	*
2008	* wpdb::update( 'table', array( 'column' => 'foo', 'field' => 'bar' ), array( 'ID' => 1 ) )
2009	* wpdb::update( 'table', array( 'column' => 'foo', 'field' => 1337 ), array( 'ID' => 1 ), array( '%s', '%d' ), array( '%d' ) )
2010	*
2011	* @since 2.5.0
2012	* @see wpdb::prepare()
2013	* @see wpdb::$field_types
2014	* @see wp_set_wpdb_vars()
2015	*
2016	* @param string $table Table name
2017	* @param array $data Data to update (in column => value pairs).
2018	* Both $data columns and $data values should be "raw" (neither should be SQL escaped).
2019	* Sending a null value will cause the column to be set to NULL - the corresponding
2020	* format is ignored in this case.
2021	* @param array $where A named array of WHERE clauses (in column => value pairs).
2022	* Multiple clauses will be joined with ANDs.
2023	* Both $where columns and $where values should be "raw".
2024	* Sending a null value will create an IS NULL comparison - the corresponding format will be ignored in this case.
2025	* @param array\|string $format Optional. An array of formats to be mapped to each of the values in $data.
2026	* If string, that format will be used for all of the values in $data.
2027	* A format is one of '%d', '%f', '%s' (integer, float, string).
2028	* If omitted, all values in $data will be treated as strings unless otherwise specified in wpdb::$field_types.
2029	* @param array\|string $where_format Optional. An array of formats to be mapped to each of the values in $where.
2030	* If string, that format will be used for all of the items in $where.
2031	* A format is one of '%d', '%f', '%s' (integer, float, string).
2032	* If omitted, all values in $where will be treated as strings.
2033	* @return int\|false The number of rows updated, or false on error.
2034	*/
2035	public function update( $table, $data, $where, $format = null, $where_format = null ) {
2036	if ( ! is_array( $data ) \|\| ! is_array( $where ) ) {
2037	return false;
2038	}
2039
2040	$data = $this->process_fields( $table, $data, $format );
2041	if ( false === $data ) {
2042	return false;
2043	}
2044	$where = $this->process_fields( $table, $where, $where_format );
2045	if ( false === $where ) {
2046	return false;
2047	}
2048
2049	$fields = $conditions = $values = array();
2050	foreach ( $data as $field => $value ) {
2051	if ( is_null( $value['value'] ) ) {
2052	$fields[] = "`$field` = NULL";
2053	continue;
2054	}
2055
2056	$fields[] = "`$field` = " . $value['format'];
2057	$values[] = $value['value'];
2058	}
2059	foreach ( $where as $field => $value ) {
2060	if ( is_null( $value['value'] ) ) {
2061	$conditions[] = "`$field` IS NULL";
2062	continue;
2063	}
2064
2065	$conditions[] = "`$field` = " . $value['format'];
2066	$values[] = $value['value'];
2067	}
2068
2069	$fields = implode( ', ', $fields );
2070	$conditions = implode( ' AND ', $conditions );
2071
2072	$sql = "UPDATE `$table` SET $fields WHERE $conditions";
2073
2074	$this->check_current_query = false;
2075	return $this->query( $this->prepare( $sql, $values ) );
2076	}
2077
2078	/**
2079	* Delete a row in the table
2080	*
2081	* wpdb::delete( 'table', array( 'ID' => 1 ) )
2082	* wpdb::delete( 'table', array( 'ID' => 1 ), array( '%d' ) )
2083	*
2084	* @since 3.4.0
2085	* @see wpdb::prepare()
2086	* @see wpdb::$field_types
2087	* @see wp_set_wpdb_vars()
2088	*
2089	* @param string $table Table name
2090	* @param array $where A named array of WHERE clauses (in column => value pairs).
2091	* Multiple clauses will be joined with ANDs.
2092	* Both $where columns and $where values should be "raw".
2093	* Sending a null value will create an IS NULL comparison - the corresponding format will be ignored in this case.
2094	* @param array\|string $where_format Optional. An array of formats to be mapped to each of the values in $where.
2095	* If string, that format will be used for all of the items in $where.
2096	* A format is one of '%d', '%f', '%s' (integer, float, string).
2097	* If omitted, all values in $where will be treated as strings unless otherwise specified in wpdb::$field_types.
2098	* @return int\|false The number of rows updated, or false on error.
2099	*/
2100	public function delete( $table, $where, $where_format = null ) {
2101	if ( ! is_array( $where ) ) {
2102	return false;
2103	}
2104
2105	$where = $this->process_fields( $table, $where, $where_format );
2106	if ( false === $where ) {
2107	return false;
2108	}
2109
2110	$conditions = $values = array();
2111	foreach ( $where as $field => $value ) {
2112	if ( is_null( $value['value'] ) ) {
2113	$conditions[] = "`$field` IS NULL";
2114	continue;
2115	}
2116
2117	$conditions[] = "`$field` = " . $value['format'];
2118	$values[] = $value['value'];
2119	}
2120
2121	$conditions = implode( ' AND ', $conditions );
2122
2123	$sql = "DELETE FROM `$table` WHERE $conditions";
2124
2125	$this->check_current_query = false;
2126	return $this->query( $this->prepare( $sql, $values ) );
2127	}
2128
2129	/**
2130	* Processes arrays of field/value pairs and field formats.
2131	*
2132	* This is a helper method for wpdb's CRUD methods, which take field/value
2133	* pairs for inserts, updates, and where clauses. This method first pairs
2134	* each value with a format. Then it determines the charset of that field,
2135	* using that to determine if any invalid text would be stripped. If text is
2136	* stripped, then field processing is rejected and the query fails.
2137	*
2138	* @since 4.2.0
2139	* @access protected
2140	*
2141	* @param string $table Table name.
2142	* @param array $data Field/value pair.
2143	* @param mixed $format Format for each field.
2144	* @return array\|false Returns an array of fields that contain paired values
2145	* and formats. Returns false for invalid values.
2146	*/
2147	protected function process_fields( $table, $data, $format ) {
2148	$data = $this->process_field_formats( $data, $format );
2149	if ( false === $data ) {
2150	return false;
2151	}
2152
2153	$data = $this->process_field_charsets( $data, $table );
2154	if ( false === $data ) {
2155	return false;
2156	}
2157
2158	$data = $this->process_field_lengths( $data, $table );
2159	if ( false === $data ) {
2160	return false;
2161	}
2162
2163	$converted_data = $this->strip_invalid_text( $data );
2164
2165	if ( $data !== $converted_data ) {
2166	return false;
2167	}
2168
2169	return $data;
2170	}
2171
2172	/**
2173	* Prepares arrays of value/format pairs as passed to wpdb CRUD methods.
2174	*
2175	* @since 4.2.0
2176	* @access protected
2177	*
2178	* @param array $data Array of fields to values.
2179	* @param mixed $format Formats to be mapped to the values in $data.
2180	* @return array Array, keyed by field names with values being an array
2181	* of 'value' and 'format' keys.
2182	*/
2183	protected function process_field_formats( $data, $format ) {
2184	$formats = $original_formats = (array) $format;
2185
2186	foreach ( $data as $field => $value ) {
2187	$value = array(
2188	'value' => $value,
2189	'format' => '%s',
2190	);
2191
2192	if ( ! empty( $format ) ) {
2193	$value['format'] = array_shift( $formats );
2194	if ( ! $value['format'] ) {
2195	$value['format'] = reset( $original_formats );
2196	}
2197	} elseif ( isset( $this->field_types[ $field ] ) ) {
2198	$value['format'] = $this->field_types[ $field ];
2199	}
2200
2201	$data[ $field ] = $value;
2202	}
2203
2204	return $data;
2205	}
2206
2207	/**
2208	* Adds field charsets to field/value/format arrays generated by
2209	* the wpdb::process_field_formats() method.
2210	*
2211	* @since 4.2.0
2212	* @access protected
2213	*
2214	* @param array $data As it comes from the wpdb::process_field_formats() method.
2215	* @param string $table Table name.
2216	* @return array\|false The same array as $data with additional 'charset' keys.
2217	*/
2218	protected function process_field_charsets( $data, $table ) {
2219	foreach ( $data as $field => $value ) {
2220	if ( '%d' === $value['format'] \|\| '%f' === $value['format'] ) {
2221	/*
2222	* We can skip this field if we know it isn't a string.
2223	* This checks %d/%f versus ! %s because its sprintf() could take more.
2224	*/
2225	$value['charset'] = false;
2226	} else {
2227	$value['charset'] = $this->get_col_charset( $table, $field );
2228	if ( is_wp_error( $value['charset'] ) ) {
2229	return false;
2230	}
2231	}
2232
2233	$data[ $field ] = $value;
2234	}
2235
2236	return $data;
2237	}
2238
2239	/**
2240	* For string fields, record the maximum string length that field can safely save.
2241	*
2242	* @since 4.2.1
2243	* @access protected
2244	*
2245	* @param array $data As it comes from the wpdb::process_field_charsets() method.
2246	* @param string $table Table name.
2247	* @return array\|false The same array as $data with additional 'length' keys, or false if
2248	* any of the values were too long for their corresponding field.
2249	*/
2250	protected function process_field_lengths( $data, $table ) {
2251	foreach ( $data as $field => $value ) {
2252	if ( '%d' === $value['format'] \|\| '%f' === $value['format'] ) {
2253	/*
2254	* We can skip this field if we know it isn't a string.
2255	* This checks %d/%f versus ! %s because its sprintf() could take more.
2256	*/
2257	$value['length'] = false;
2258	} else {
2259	$value['length'] = $this->get_col_length( $table, $field );
2260	if ( is_wp_error( $value['length'] ) ) {
2261	return false;
2262	}
2263	}
2264
2265	$data[ $field ] = $value;
2266	}
2267
2268	return $data;
2269	}
2270
2271	/**
2272	* Retrieve one variable from the database.
2273	*
2274	* Executes a SQL query and returns the value from the SQL result.
2275	* If the SQL result contains more than one column and/or more than one row, this function returns the value in the column and row specified.
2276	* If $query is null, this function returns the value in the specified column and row from the previous SQL result.
2277	*
2278	* @since 0.71
2279	*
2280	* @param string\|null $query Optional. SQL query. Defaults to null, use the result from the previous query.
2281	* @param int $x Optional. Column of value to return. Indexed from 0.
2282	* @param int $y Optional. Row of value to return. Indexed from 0.
2283	* @return string\|null Database query result (as string), or null on failure
2284	*/
2285	public function get_var( $query = null, $x = 0, $y = 0 ) {
2286	$this->func_call = "\$db->get_var(\"$query\", $x, $y)";
2287
2288	if ( $this->check_current_query && $this->check_safe_collation( $query ) ) {
2289	$this->check_current_query = false;
2290	}
2291
2292	if ( $query ) {
2293	$this->query( $query );
2294	}
2295
2296	// Extract var out of cached results based x,y vals
2297	if ( !empty( $this->last_result[$y] ) ) {
2298	$values = array_values( get_object_vars( $this->last_result[$y] ) );
2299	}
2300
2301	// If there is a value return it else return null
2302	return ( isset( $values[$x] ) && $values[$x] !== '' ) ? $values[$x] : null;
2303	}
2304
2305	/**
2306	* Retrieve one row from the database.
2307	*
2308	* Executes a SQL query and returns the row from the SQL result.
2309	*
2310	* @since 0.71
2311	*
2312	* @param string\|null $query SQL query.
2313	* @param string $output Optional. The required return type. One of OBJECT, ARRAY_A, or ARRAY_N, which correspond to
2314	* an stdClass object, an associative array, or a numeric array, respectively. Default OBJECT.
2315	* @param int $y Optional. Row to return. Indexed from 0.
2316	* @return array\|object\|null\|void Database query result in format specified by $output or null on failure
2317	*/
2318	public function get_row( $query = null, $output = OBJECT, $y = 0 ) {
2319	$this->func_call = "\$db->get_row(\"$query\",$output,$y)";
2320
2321	if ( $this->check_current_query && $this->check_safe_collation( $query ) ) {
2322	$this->check_current_query = false;
2323	}
2324
2325	if ( $query ) {
2326	$this->query( $query );
2327	} else {
2328	return null;
2329	}
2330
2331	if ( !isset( $this->last_result[$y] ) )
2332	return null;
2333
2334	if ( $output == OBJECT ) {
2335	return $this->last_result[$y] ? $this->last_result[$y] : null;
2336	} elseif ( $output == ARRAY_A ) {
2337	return $this->last_result[$y] ? get_object_vars( $this->last_result[$y] ) : null;
2338	} elseif ( $output == ARRAY_N ) {
2339	return $this->last_result[$y] ? array_values( get_object_vars( $this->last_result[$y] ) ) : null;
2340	} elseif ( strtoupper( $output ) === OBJECT ) {
2341	// Back compat for OBJECT being previously case insensitive.
2342	return $this->last_result[$y] ? $this->last_result[$y] : null;
2343	} else {
2344	$this->print_error( " \$db->get_row(string query, output type, int offset) -- Output type must be one of: OBJECT, ARRAY_A, ARRAY_N" );
2345	}
2346	}
2347
2348	/**
2349	* Retrieve one column from the database.
2350	*
2351	* Executes a SQL query and returns the column from the SQL result.
2352	* If the SQL result contains more than one column, this function returns the column specified.
2353	* If $query is null, this function returns the specified column from the previous SQL result.
2354	*
2355	* @since 0.71
2356	*
2357	* @param string\|null $query Optional. SQL query. Defaults to previous query.
2358	* @param int $x Optional. Column to return. Indexed from 0.
2359	* @return array Database query result. Array indexed from 0 by SQL result row number.
2360	*/
2361	public function get_col( $query = null , $x = 0 ) {
2362	if ( $this->check_current_query && $this->check_safe_collation( $query ) ) {
2363	$this->check_current_query = false;
2364	}
2365
2366	if ( $query ) {
2367	$this->query( $query );
2368	}
2369
2370	$new_array = array();
2371	// Extract the column values
2372	for ( $i = 0, $j = count( $this->last_result ); $i < $j; $i++ ) {
2373	$new_array[$i] = $this->get_var( null, $x, $i );
2374	}
2375	return $new_array;
2376	}
2377
2378	/**
2379	* Retrieve an entire SQL result set from the database (i.e., many rows)
2380	*
2381	* Executes a SQL query and returns the entire SQL result.
2382	*
2383	* @since 0.71
2384	*
2385	* @param string $query SQL query.
2386	* @param string $output Optional. Any of ARRAY_A \| ARRAY_N \| OBJECT \| OBJECT_K constants.
2387	* With one of the first three, return an array of rows indexed from 0 by SQL result row number.
2388	* Each row is an associative array (column => value, ...), a numerically indexed array (0 => value, ...), or an object. ( ->column = value ), respectively.
2389	* With OBJECT_K, return an associative array of row objects keyed by the value of each row's first column's value.
2390	* Duplicate keys are discarded.
2391	* @return array\|object\|null Database query results
2392	*/
2393	public function get_results( $query = null, $output = OBJECT ) {
2394	$this->func_call = "\$db->get_results(\"$query\", $output)";
2395
2396	if ( $this->check_current_query && $this->check_safe_collation( $query ) ) {
2397	$this->check_current_query = false;
2398	}
2399
2400	if ( $query ) {
2401	$this->query( $query );
2402	} else {
2403	return null;
2404	}
2405
2406	$new_array = array();
2407	if ( $output == OBJECT ) {
2408	// Return an integer-keyed array of row objects
2409	return $this->last_result;
2410	} elseif ( $output == OBJECT_K ) {
2411	// Return an array of row objects with keys from column 1
2412	// (Duplicates are discarded)
2413	foreach ( $this->last_result as $row ) {
2414	$var_by_ref = get_object_vars( $row );
2415	$key = array_shift( $var_by_ref );
2416	if ( ! isset( $new_array[ $key ] ) )
2417	$new_array[ $key ] = $row;
2418	}
2419	return $new_array;
2420	} elseif ( $output == ARRAY_A \|\| $output == ARRAY_N ) {
2421	// Return an integer-keyed array of...
2422	if ( $this->last_result ) {
2423	foreach ( (array) $this->last_result as $row ) {
2424	if ( $output == ARRAY_N ) {
2425	// ...integer-keyed row arrays
2426	$new_array[] = array_values( get_object_vars( $row ) );
2427	} else {
2428	// ...column name-keyed row arrays
2429	$new_array[] = get_object_vars( $row );
2430	}
2431	}
2432	}
2433	return $new_array;
2434	} elseif ( strtoupper( $output ) === OBJECT ) {
2435	// Back compat for OBJECT being previously case insensitive.
2436	return $this->last_result;
2437	}
2438	return null;
2439	}
2440
2441	/**
2442	* Retrieves the character set for the given table.
2443	*
2444	* @since 4.2.0
2445	* @access protected
2446	*
2447	* @param string $table Table name.
2448	* @return string\|WP_Error Table character set, WP_Error object if it couldn't be found.
2449	*/
2450	protected function get_table_charset( $table ) {
2451	$tablekey = strtolower( $table );
2452
2453	/**
2454	* Filters the table charset value before the DB is checked.
2455	*
2456	* Passing a non-null value to the filter will effectively short-circuit
2457	* checking the DB for the charset, returning that value instead.
2458	*
2459	* @since 4.2.0
2460	*
2461	* @param string $charset The character set to use. Default null.
2462	* @param string $table The name of the table being checked.
2463	*/
2464	$charset = apply_filters( 'pre_get_table_charset', null, $table );
2465	if ( null !== $charset ) {
2466	return $charset;
2467	}
2468
2469	if ( isset( $this->table_charset[ $tablekey ] ) ) {
2470	return $this->table_charset[ $tablekey ];
2471	}
2472
2473	$charsets = $columns = array();
2474
2475	$table_parts = explode( '.', $table );
2476	$table = '`' . implode( '`.`', $table_parts ) . '`';
2477	$results = $this->get_results( "SHOW FULL COLUMNS FROM $table" );
2478	if ( ! $results ) {
2479	return new WP_Error( 'wpdb_get_table_charset_failure' );
2480	}
2481
2482	foreach ( $results as $column ) {
2483	$columns[ strtolower( $column->Field ) ] = $column;
2484	}
2485
2486	$this->col_meta[ $tablekey ] = $columns;
2487
2488	foreach ( $columns as $column ) {
2489	if ( ! empty( $column->Collation ) ) {
2490	list( $charset ) = explode( '_', $column->Collation );
2491
2492	// If the current connection can't support utf8mb4 characters, let's only send 3-byte utf8 characters.
2493	if ( 'utf8mb4' === $charset && ! $this->has_cap( 'utf8mb4' ) ) {
2494	$charset = 'utf8';
2495	}
2496
2497	$charsets[ strtolower( $charset ) ] = true;
2498	}
2499
2500	list( $type ) = explode( '(', $column->Type );
2501
2502	// A binary/blob means the whole query gets treated like this.
2503	if ( in_array( strtoupper( $type ), array( 'BINARY', 'VARBINARY', 'TINYBLOB', 'MEDIUMBLOB', 'BLOB', 'LONGBLOB' ) ) ) {
2504	$this->table_charset[ $tablekey ] = 'binary';
2505	return 'binary';
2506	}
2507	}
2508
2509	// utf8mb3 is an alias for utf8.
2510	if ( isset( $charsets['utf8mb3'] ) ) {
2511	$charsets['utf8'] = true;
2512	unset( $charsets['utf8mb3'] );
2513	}
2514
2515	// Check if we have more than one charset in play.
2516	$count = count( $charsets );
2517	if ( 1 === $count ) {
2518	$charset = key( $charsets );
2519	} elseif ( 0 === $count ) {
2520	// No charsets, assume this table can store whatever.
2521	$charset = false;
2522	} else {
2523	// More than one charset. Remove latin1 if present and recalculate.
2524	unset( $charsets['latin1'] );
2525	$count = count( $charsets );
2526	if ( 1 === $count ) {
2527	// Only one charset (besides latin1).
2528	$charset = key( $charsets );
2529	} elseif ( 2 === $count && isset( $charsets['utf8'], $charsets['utf8mb4'] ) ) {
2530	// Two charsets, but they're utf8 and utf8mb4, use utf8.
2531	$charset = 'utf8';
2532	} else {
2533	// Two mixed character sets. ascii.
2534	$charset = 'ascii';
2535	}
2536	}
2537
2538	$this->table_charset[ $tablekey ] = $charset;
2539	return $charset;
2540	}
2541
2542	/**
2543	* Retrieves the character set for the given column.
2544	*
2545	* @since 4.2.0
2546	* @access public
2547	*
2548	* @param string $table Table name.
2549	* @param string $column Column name.
2550	* @return string\|false\|WP_Error Column character set as a string. False if the column has no
2551	* character set. WP_Error object if there was an error.
2552	*/
2553	public function get_col_charset( $table, $column ) {
2554	$tablekey = strtolower( $table );
2555	$columnkey = strtolower( $column );
2556
2557	/**
2558	* Filters the column charset value before the DB is checked.
2559	*
2560	* Passing a non-null value to the filter will short-circuit
2561	* checking the DB for the charset, returning that value instead.
2562	*
2563	* @since 4.2.0
2564	*
2565	* @param string $charset The character set to use. Default null.
2566	* @param string $table The name of the table being checked.
2567	* @param string $column The name of the column being checked.
2568	*/
2569	$charset = apply_filters( 'pre_get_col_charset', null, $table, $column );
2570	if ( null !== $charset ) {
2571	return $charset;
2572	}
2573
2574	// Skip this entirely if this isn't a MySQL database.
2575	if ( empty( $this->is_mysql ) ) {
2576	return false;
2577	}
2578
2579	if ( empty( $this->table_charset[ $tablekey ] ) ) {
2580	// This primes column information for us.
2581	$table_charset = $this->get_table_charset( $table );
2582	if ( is_wp_error( $table_charset ) ) {
2583	return $table_charset;
2584	}
2585	}
2586
2587	// If still no column information, return the table charset.
2588	if ( empty( $this->col_meta[ $tablekey ] ) ) {
2589	return $this->table_charset[ $tablekey ];
2590	}
2591
2592	// If this column doesn't exist, return the table charset.
2593	if ( empty( $this->col_meta[ $tablekey ][ $columnkey ] ) ) {
2594	return $this->table_charset[ $tablekey ];
2595	}
2596
2597	// Return false when it's not a string column.
2598	if ( empty( $this->col_meta[ $tablekey ][ $columnkey ]->Collation ) ) {
2599	return false;
2600	}
2601
2602	list( $charset ) = explode( '_', $this->col_meta[ $tablekey ][ $columnkey ]->Collation );
2603	return $charset;
2604	}
2605
2606	/**
2607	* Retrieve the maximum string length allowed in a given column.
2608	* The length may either be specified as a byte length or a character length.
2609	*
2610	* @since 4.2.1
2611	* @access public
2612	*
2613	* @param string $table Table name.
2614	* @param string $column Column name.
2615	* @return array\|false\|WP_Error array( 'length' => (int), 'type' => 'byte' \| 'char' )
2616	* false if the column has no length (for example, numeric column)
2617	* WP_Error object if there was an error.
2618	*/
2619	public function get_col_length( $table, $column ) {
2620	$tablekey = strtolower( $table );
2621	$columnkey = strtolower( $column );
2622
2623	// Skip this entirely if this isn't a MySQL database.
2624	if ( empty( $this->is_mysql ) ) {
2625	return false;
2626	}
2627
2628	if ( empty( $this->col_meta[ $tablekey ] ) ) {
2629	// This primes column information for us.
2630	$table_charset = $this->get_table_charset( $table );
2631	if ( is_wp_error( $table_charset ) ) {
2632	return $table_charset;
2633	}
2634	}
2635
2636	if ( empty( $this->col_meta[ $tablekey ][ $columnkey ] ) ) {
2637	return false;
2638	}
2639
2640	$typeinfo = explode( '(', $this->col_meta[ $tablekey ][ $columnkey ]->Type );
2641
2642	$type = strtolower( $typeinfo[0] );
2643	if ( ! empty( $typeinfo[1] ) ) {
2644	$length = trim( $typeinfo[1], ')' );
2645	} else {
2646	$length = false;
2647	}
2648
2649	switch( $type ) {
2650	case 'char':
2651	case 'varchar':
2652	return array(
2653	'type' => 'char',
2654	'length' => (int) $length,
2655	);
2656
2657	case 'binary':
2658	case 'varbinary':
2659	return array(
2660	'type' => 'byte',
2661	'length' => (int) $length,
2662	);
2663
2664	case 'tinyblob':
2665	case 'tinytext':
2666	return array(
2667	'type' => 'byte',
2668	'length' => 255, // 2^8 - 1
2669	);
2670
2671	case 'blob':
2672	case 'text':
2673	return array(
2674	'type' => 'byte',
2675	'length' => 65535, // 2^16 - 1
2676	);
2677
2678	case 'mediumblob':
2679	case 'mediumtext':
2680	return array(
2681	'type' => 'byte',
2682	'length' => 16777215, // 2^24 - 1
2683	);
2684
2685	case 'longblob':
2686	case 'longtext':
2687	return array(
2688	'type' => 'byte',
2689	'length' => 4294967295, // 2^32 - 1
2690	);
2691
2692	default:
2693	return false;
2694	}
2695	}
2696
2697	/**
2698	* Check if a string is ASCII.
2699	*
2700	* The negative regex is faster for non-ASCII strings, as it allows
2701	* the search to finish as soon as it encounters a non-ASCII character.
2702	*
2703	* @since 4.2.0
2704	* @access protected
2705	*
2706	* @param string $string String to check.
2707	* @return bool True if ASCII, false if not.
2708	*/
2709	protected function check_ascii( $string ) {
2710	if ( function_exists( 'mb_check_encoding' ) ) {
2711	if ( mb_check_encoding( $string, 'ASCII' ) ) {
2712	return true;
2713	}
2714	} elseif ( ! preg_match( '/[^\x00-\x7F]/', $string ) ) {
2715	return true;
2716	}
2717
2718	return false;
2719	}
2720
2721	/**
2722	* Check if the query is accessing a collation considered safe on the current version of MySQL.
2723	*
2724	* @since 4.2.0
2725	* @access protected
2726	*
2727	* @param string $query The query to check.
2728	* @return bool True if the collation is safe, false if it isn't.
2729	*/
2730	protected function check_safe_collation( $query ) {
2731	if ( $this->checking_collation ) {
2732	return true;
2733	}
2734
2735	// We don't need to check the collation for queries that don't read data.
2736	$query = ltrim( $query, "\r\n\t (" );
2737	if ( preg_match( '/^(?:SHOW\|DESCRIBE\|DESC\|EXPLAIN\|CREATE)\s/i', $query ) ) {
2738	return true;
2739	}
2740
2741	// All-ASCII queries don't need extra checking.
2742	if ( $this->check_ascii( $query ) ) {
2743	return true;
2744	}
2745
2746	$table = $this->get_table_from_query( $query );
2747	if ( ! $table ) {
2748	return false;
2749	}
2750
2751	$this->checking_collation = true;
2752	$collation = $this->get_table_charset( $table );
2753	$this->checking_collation = false;
2754
2755	// Tables with no collation, or latin1 only, don't need extra checking.
2756	if ( false === $collation \|\| 'latin1' === $collation ) {
2757	return true;
2758	}
2759
2760	$table = strtolower( $table );
2761	if ( empty( $this->col_meta[ $table ] ) ) {
2762	return false;
2763	}
2764
2765	// If any of the columns don't have one of these collations, it needs more sanity checking.
2766	foreach ( $this->col_meta[ $table ] as $col ) {
2767	if ( empty( $col->Collation ) ) {
2768	continue;
2769	}
2770
2771	if ( ! in_array( $col->Collation, array( 'utf8_general_ci', 'utf8_bin', 'utf8mb4_general_ci', 'utf8mb4_bin' ), true ) ) {
2772	return false;
2773	}
2774	}
2775
2776	return true;
2777	}
2778
2779	/**
2780	* Strips any invalid characters based on value/charset pairs.
2781	*
2782	* @since 4.2.0
2783	* @access protected
2784	*
2785	* @param array $data Array of value arrays. Each value array has the keys
2786	* 'value' and 'charset'. An optional 'ascii' key can be
2787	* set to false to avoid redundant ASCII checks.
2788	* @return array\|WP_Error The $data parameter, with invalid characters removed from
2789	* each value. This works as a passthrough: any additional keys
2790	* such as 'field' are retained in each value array. If we cannot
2791	* remove invalid characters, a WP_Error object is returned.
2792	*/
2793	protected function strip_invalid_text( $data ) {
2794	$db_check_string = false;
2795
2796	foreach ( $data as &$value ) {
2797	$charset = $value['charset'];
2798
2799	if ( is_array( $value['length'] ) ) {
2800	$length = $value['length']['length'];
2801	$truncate_by_byte_length = 'byte' === $value['length']['type'];
2802	} else {
2803	$length = false;
2804	// Since we have no length, we'll never truncate.
2805	// Initialize the variable to false. true would take us
2806	// through an unnecessary (for this case) codepath below.
2807	$truncate_by_byte_length = false;
2808	}
2809
2810	// There's no charset to work with.
2811	if ( false === $charset ) {
2812	continue;
2813	}
2814
2815	// Column isn't a string.
2816	if ( ! is_string( $value['value'] ) ) {
2817	continue;
2818	}
2819
2820	$needs_validation = true;
2821	if (
2822	// latin1 can store any byte sequence
2823	'latin1' === $charset
2824	\|\|
2825	// ASCII is always OK.
2826	( ! isset( $value['ascii'] ) && $this->check_ascii( $value['value'] ) )
2827	) {
2828	$truncate_by_byte_length = true;
2829	$needs_validation = false;
2830	}
2831
2832	if ( $truncate_by_byte_length ) {
2833	mbstring_binary_safe_encoding();
2834	if ( false !== $length && strlen( $value['value'] ) > $length ) {
2835	$value['value'] = substr( $value['value'], 0, $length );
2836	}
2837	reset_mbstring_encoding();
2838
2839	if ( ! $needs_validation ) {
2840	continue;
2841	}
2842	}
2843
2844	// utf8 can be handled by regex, which is a bunch faster than a DB lookup.
2845	if ( ( 'utf8' === $charset \|\| 'utf8mb3' === $charset \|\| 'utf8mb4' === $charset ) && function_exists( 'mb_strlen' ) ) {
2846	$regex = '/
2847	(
2848	(?: [\x00-\x7F] # single-byte sequences 0xxxxxxx
2849	\| [\xC2-\xDF][\x80-\xBF] # double-byte sequences 110xxxxx 10xxxxxx
2850	\| \xE0[\xA0-\xBF][\x80-\xBF] # triple-byte sequences 1110xxxx 10xxxxxx * 2
2851	\| [\xE1-\xEC][\x80-\xBF]{2}
2852	\| \xED[\x80-\x9F][\x80-\xBF]
2853	\| [\xEE-\xEF][\x80-\xBF]{2}';
2854
2855	if ( 'utf8mb4' === $charset ) {
2856	$regex .= '
2857	\| \xF0[\x90-\xBF][\x80-\xBF]{2} # four-byte sequences 11110xxx 10xxxxxx * 3
2858	\| [\xF1-\xF3][\x80-\xBF]{3}
2859	\| \xF4[\x80-\x8F][\x80-\xBF]{2}
2860	';
2861	}
2862
2863	$regex .= '){1,40} # ...one or more times
2864	)
2865	\| . # anything else
2866	/x';
2867	$value['value'] = preg_replace( $regex, '$1', $value['value'] );
2868
2869
2870	if ( false !== $length && mb_strlen( $value['value'], 'UTF-8' ) > $length ) {
2871	$value['value'] = mb_substr( $value['value'], 0, $length, 'UTF-8' );
2872	}
2873	continue;
2874	}
2875
2876	// We couldn't use any local conversions, send it to the DB.
2877	$value['db'] = $db_check_string = true;
2878	}
2879	unset( $value ); // Remove by reference.
2880
2881	if ( $db_check_string ) {
2882	$queries = array();
2883	foreach ( $data as $col => $value ) {
2884	if ( ! empty( $value['db'] ) ) {
2885	// We're going to need to truncate by characters or bytes, depending on the length value we have.
2886	if ( 'byte' === $value['length']['type'] ) {
2887	// Using binary causes LEFT() to truncate by bytes.
2888	$charset = 'binary';
2889	} else {
2890	$charset = $value['charset'];
2891	}
2892
2893	if ( $this->charset ) {
2894	$connection_charset = $this->charset;
2895	} else {
2896	if ( $this->use_mysqli ) {
2897	$connection_charset = mysqli_character_set_name( $this->dbh );
2898	} else {
2899	$connection_charset = mysql_client_encoding();
2900	}
2901	}
2902
2903	if ( is_array( $value['length'] ) ) {
2904	$length = sprintf( '%.0f', $value['length']['length'] );
2905	$queries[ $col ] = $this->prepare( "CONVERT( LEFT( CONVERT( %s USING $charset ), $length ) USING $connection_charset )", $value['value'] );
2906	} else if ( 'binary' !== $charset ) {
2907	// If we don't have a length, there's no need to convert binary - it will always return the same result.
2908	$queries[ $col ] = $this->prepare( "CONVERT( CONVERT( %s USING $charset ) USING $connection_charset )", $value['value'] );
2909	}
2910
2911	unset( $data[ $col ]['db'] );
2912	}
2913	}
2914
2915	$sql = array();
2916	foreach ( $queries as $column => $query ) {
2917	if ( ! $query ) {
2918	continue;
2919	}
2920
2921	$sql[] = $query . " AS x_$column";
2922	}
2923
2924	$this->check_current_query = false;
2925	$row = $this->get_row( "SELECT " . implode( ', ', $sql ), ARRAY_A );
2926	if ( ! $row ) {
2927	return new WP_Error( 'wpdb_strip_invalid_text_failure' );
2928	}
2929
2930	foreach ( array_keys( $data ) as $column ) {
2931	if ( isset( $row["x_$column"] ) ) {
2932	$data[ $column ]['value'] = $row["x_$column"];
2933	}
2934	}
2935	}
2936
2937	return $data;
2938	}
2939
2940	/**
2941	* Strips any invalid characters from the query.
2942	*
2943	* @since 4.2.0
2944	* @access protected
2945	*
2946	* @param string $query Query to convert.
2947	* @return string\|WP_Error The converted query, or a WP_Error object if the conversion fails.
2948	*/
2949	protected function strip_invalid_text_from_query( $query ) {
2950	// We don't need to check the collation for queries that don't read data.
2951	$trimmed_query = ltrim( $query, "\r\n\t (" );
2952	if ( preg_match( '/^(?:SHOW\|DESCRIBE\|DESC\|EXPLAIN\|CREATE)\s/i', $trimmed_query ) ) {
2953	return $query;
2954	}
2955
2956	$table = $this->get_table_from_query( $query );
2957	if ( $table ) {
2958	$charset = $this->get_table_charset( $table );
2959	if ( is_wp_error( $charset ) ) {
2960	return $charset;
2961	}
2962
2963	// We can't reliably strip text from tables containing binary/blob columns
2964	if ( 'binary' === $charset ) {
2965	return $query;
2966	}
2967	} else {
2968	$charset = $this->charset;
2969	}
2970
2971	$data = array(
2972	'value' => $query,
2973	'charset' => $charset,
2974	'ascii' => false,
2975	'length' => false,
2976	);
2977
2978	$data = $this->strip_invalid_text( array( $data ) );
2979	if ( is_wp_error( $data ) ) {
2980	return $data;
2981	}
2982
2983	return $data[0]['value'];
2984	}
2985
2986	/**
2987	* Strips any invalid characters from the string for a given table and column.
2988	*
2989	* @since 4.2.0
2990	* @access public
2991	*
2992	* @param string $table Table name.
2993	* @param string $column Column name.
2994	* @param string $value The text to check.
2995	* @return string\|WP_Error The converted string, or a WP_Error object if the conversion fails.
2996	*/
2997	public function strip_invalid_text_for_column( $table, $column, $value ) {
2998	if ( ! is_string( $value ) ) {
2999	return $value;
3000	}
3001
3002	$charset = $this->get_col_charset( $table, $column );
3003	if ( ! $charset ) {
3004	// Not a string column.
3005	return $value;
3006	} elseif ( is_wp_error( $charset ) ) {
3007	// Bail on real errors.
3008	return $charset;
3009	}
3010
3011	$data = array(
3012	$column => array(
3013	'value' => $value,
3014	'charset' => $charset,
3015	'length' => $this->get_col_length( $table, $column ),
3016	)
3017	);
3018
3019	$data = $this->strip_invalid_text( $data );
3020	if ( is_wp_error( $data ) ) {
3021	return $data;
3022	}
3023
3024	return $data[ $column ]['value'];
3025	}
3026
3027	/**
3028	* Find the first table name referenced in a query.
3029	*
3030	* @since 4.2.0
3031	* @access protected
3032	*
3033	* @param string $query The query to search.
3034	* @return string\|false $table The table name found, or false if a table couldn't be found.
3035	*/
3036	protected function get_table_from_query( $query ) {
3037	// Remove characters that can legally trail the table name.
3038	$query = rtrim( $query, ';/-#' );
3039
3040	// Allow (select...) union [...] style queries. Use the first query's table name.
3041	$query = ltrim( $query, "\r\n\t (" );
3042
3043	// Strip everything between parentheses except nested selects.
3044	$query = preg_replace( '/$(?!\sselect)[^(]?$/is', '()', $query );
3045
3046	// Quickly match most common queries.
3047	if ( preg_match( '/^\s*(?:'
3048	. 'SELECT.*?\s+FROM'
3049	. '\|INSERT(?:\s+LOW_PRIORITY\|\s+DELAYED\|\s+HIGH_PRIORITY)?(?:\s+IGNORE)?(?:\s+INTO)?'
3050	. '\|REPLACE(?:\s+LOW_PRIORITY\|\s+DELAYED)?(?:\s+INTO)?'
3051	. '\|UPDATE(?:\s+LOW_PRIORITY)?(?:\s+IGNORE)?'
3052	. '\|DELETE(?:\s+LOW_PRIORITY\|\s+QUICK\|\s+IGNORE)*(?:.+?FROM)?'
3053	. ')\s+((?:[0-9a-zA-Z$_.`-]\|[\xC2-\xDF][\x80-\xBF])+)/is', $query, $maybe ) ) {
3054	return str_replace( '`', '', $maybe[1] );
3055	}
3056
3057	// SHOW TABLE STATUS and SHOW TABLES WHERE Name = 'wp_posts'
3058	if ( preg_match( '/^\sSHOW\s+(?:TABLE\s+STATUS\|(?:FULL\s+)?TABLES).+WHERE\s+Name\s=\s*("\|\')((?:[0-9a-zA-Z$_.-]\|[\xC2-\xDF][\x80-\xBF])+)\\1/is', $query, $maybe ) ) {
3059	return $maybe[2];
3060	}
3061
3062	// SHOW TABLE STATUS LIKE and SHOW TABLES LIKE 'wp\_123\_%'
3063	// This quoted LIKE operand seldom holds a full table name.
3064	// It is usually a pattern for matching a prefix so we just
3065	// strip the trailing % and unescape the _ to get 'wp_123_'
3066	// which drop-ins can use for routing these SQL statements.
3067	if ( preg_match( '/^\sSHOW\s+(?:TABLE\s+STATUS\|(?:FULL\s+)?TABLES)\s+(?:WHERE\s+Name\s+)?LIKE\s("\|\')((?:[\\\\0-9a-zA-Z$_.-]\|[\xC2-\xDF][\x80-\xBF])+)%?\\1/is', $query, $maybe ) ) {
3068	return str_replace( '\\_', '_', $maybe[2] );
3069	}
3070
3071	// Big pattern for the rest of the table-related queries.
3072	if ( preg_match( '/^\s*(?:'
3073	. '(?:EXPLAIN\s+(?:EXTENDED\s+)?)?SELECT.*?\s+FROM'
3074	. '\|DESCRIBE\|DESC\|EXPLAIN\|HANDLER'
3075	. '\|(?:LOCK\|UNLOCK)\s+TABLE(?:S)?'
3076	. '\|(?:RENAME\|OPTIMIZE\|BACKUP\|RESTORE\|CHECK\|CHECKSUM\|ANALYZE\|REPAIR).*\s+TABLE'
3077	. '\|TRUNCATE(?:\s+TABLE)?'
3078	. '\|CREATE(?:\s+TEMPORARY)?\s+TABLE(?:\s+IF\s+NOT\s+EXISTS)?'
3079	. '\|ALTER(?:\s+IGNORE)?\s+TABLE'
3080	. '\|DROP\s+TABLE(?:\s+IF\s+EXISTS)?'
3081	. '\|CREATE(?:\s+\w+)?\s+INDEX.*\s+ON'
3082	. '\|DROP\s+INDEX.*\s+ON'
3083	. '\|LOAD\s+DATA.INFILE.INTO\s+TABLE'
3084	. '\|(?:GRANT\|REVOKE).*ON\s+TABLE'
3085	. '\|SHOW\s+(?:.FROM\|.TABLE)'
3086	. ')\s+$\s((?:[0-9a-zA-Z$_.`-]\|[\xC2-\xDF][\x80-\xBF])+)\s$/is', $query, $maybe ) ) {
3087	return str_replace( '`', '', $maybe[1] );
3088	}
3089
3090	return false;
3091	}
3092
3093	/**
3094	* Load the column metadata from the last query.
3095	*
3096	* @since 3.5.0
3097	*
3098	* @access protected
3099	*/
3100	protected function load_col_info() {
3101	if ( $this->col_info )
3102	return;
3103
3104	if ( $this->use_mysqli ) {
3105	$num_fields = mysqli_num_fields( $this->result );
3106	for ( $i = 0; $i < $num_fields; $i++ ) {
3107	$this->col_info[ $i ] = mysqli_fetch_field( $this->result );
3108	}
3109	} else {
3110	$num_fields = mysql_num_fields( $this->result );
3111	for ( $i = 0; $i < $num_fields; $i++ ) {
3112	$this->col_info[ $i ] = mysql_fetch_field( $this->result, $i );
3113	}
3114	}
3115	}
3116
3117	/**
3118	* Retrieve column metadata from the last query.
3119	*
3120	* @since 0.71
3121	*
3122	* @param string $info_type Optional. Type one of name, table, def, max_length, not_null, primary_key, multiple_key, unique_key, numeric, blob, type, unsigned, zerofill
3123	* @param int $col_offset Optional. 0: col name. 1: which table the col's in. 2: col's max length. 3: if the col is numeric. 4: col's type
3124	* @return mixed Column Results
3125	*/
3126	public function get_col_info( $info_type = 'name', $col_offset = -1 ) {
3127	$this->load_col_info();
3128
3129	if ( $this->col_info ) {
3130	if ( $col_offset == -1 ) {
3131	$i = 0;
3132	$new_array = array();
3133	foreach ( (array) $this->col_info as $col ) {
3134	$new_array[$i] = $col->{$info_type};
3135	$i++;
3136	}
3137	return $new_array;
3138	} else {
3139	return $this->col_info[$col_offset]->{$info_type};
3140	}
3141	}
3142	}
3143
3144	/**
3145	* Starts the timer, for debugging purposes.
3146	*
3147	* @since 1.5.0
3148	*
3149	* @return true
3150	*/
3151	public function timer_start() {
3152	$this->time_start = microtime( true );
3153	return true;
3154	}
3155
3156	/**
3157	* Stops the debugging timer.
3158	*
3159	* @since 1.5.0
3160	*
3161	* @return float Total time spent on the query, in seconds
3162	*/
3163	public function timer_stop() {
3164	return ( microtime( true ) - $this->time_start );
3165	}
3166
3167	/**
3168	* Wraps errors in a nice header and footer and dies.
3169	*
3170	* Will not die if wpdb::$show_errors is false.
3171	*
3172	* @since 1.5.0
3173	*
3174	* @param string $message The Error message
3175	* @param string $error_code Optional. A Computer readable string to identify the error.
3176	* @return false\|void
3177	*/
3178	public function bail( $message, $error_code = '500' ) {
3179	if ( !$this->show_errors ) {
3180	if ( class_exists( 'WP_Error', false ) ) {
3181	$this->error = new WP_Error($error_code, $message);
3182	} else {
3183	$this->error = $message;
3184	}
3185	return false;
3186	}
3187	wp_die($message);
3188	}
3189
3190
3191	/**
3192	* Closes the current database connection.
3193	*
3194	* @since 4.5.0
3195	* @access public
3196	*
3197	* @return bool True if the connection was successfully closed, false if it wasn't,
3198	* or the connection doesn't exist.
3199	*/
3200	public function close() {
3201	if ( ! $this->dbh ) {
3202	return false;
3203	}
3204
3205	if ( $this->use_mysqli ) {
3206	$closed = mysqli_close( $this->dbh );
3207	} else {
3208	$closed = mysql_close( $this->dbh );
3209	}
3210
3211	if ( $closed ) {
3212	$this->dbh = null;
3213	$this->ready = false;
3214	$this->has_connected = false;
3215	}
3216
3217	return $closed;
3218	}
3219
3220	/**
3221	* Whether MySQL database is at least the required minimum version.
3222	*
3223	* @since 2.5.0
3224	*
3225	* @global string $wp_version
3226	* @global string $required_mysql_version
3227	*
3228	* @return WP_Error\|void
3229	*/
3230	public function check_database_version() {
3231	global $wp_version, $required_mysql_version;
3232	// Make sure the server has the required MySQL version
3233	if ( version_compare($this->db_version(), $required_mysql_version, '<') ) {
3234	/* translators: 1: WordPress version number, 2: Minimum required MySQL version number */
3235	return new WP_Error('database_version', sprintf( __( '<strong>ERROR</strong>: WordPress %1$s requires MySQL %2$s or higher' ), $wp_version, $required_mysql_version ));
3236	}
3237	}
3238
3239	/**
3240	* Whether the database supports collation.
3241	*
3242	* Called when WordPress is generating the table scheme.
3243	*
3244	* Use `wpdb::has_cap( 'collation' )`.
3245	*
3246	* @since 2.5.0
3247	* @deprecated 3.5.0 Use wpdb::has_cap()
3248	*
3249	* @return bool True if collation is supported, false if version does not
3250	*/
3251	public function supports_collation() {
3252	_deprecated_function( __FUNCTION__, '3.5.0', 'wpdb::has_cap( \'collation\' )' );
3253	return $this->has_cap( 'collation' );
3254	}
3255
3256	/**
3257	* The database character collate.
3258	*
3259	* @since 3.5.0
3260	*
3261	* @return string The database character collate.
3262	*/
3263	public function get_charset_collate() {
3264	$charset_collate = '';
3265
3266	if ( ! empty( $this->charset ) )
3267	$charset_collate = "DEFAULT CHARACTER SET $this->charset";
3268	if ( ! empty( $this->collate ) )
3269	$charset_collate .= " COLLATE $this->collate";
3270
3271	return $charset_collate;
3272	}
3273
3274	/**
3275	* Determine if a database supports a particular feature.
3276	*
3277	* @since 2.7.0
3278	* @since 4.1.0 Added support for the 'utf8mb4' feature.
3279	* @since 4.6.0 Added support for the 'utf8mb4_520' feature.
3280	*
3281	* @see wpdb::db_version()
3282	*
3283	* @param string $db_cap The feature to check for. Accepts 'collation',
3284	* 'group_concat', 'subqueries', 'set_charset',
3285	* or 'utf8mb4'.
3286	* @return int\|false Whether the database feature is supported, false otherwise.
3287	*/
3288	public function has_cap( $db_cap ) {
3289	$version = $this->db_version();
3290
3291	switch ( strtolower( $db_cap ) ) {
3292	case 'collation' : // @since 2.5.0
3293	case 'group_concat' : // @since 2.7.0
3294	case 'subqueries' : // @since 2.7.0
3295	return version_compare( $version, '4.1', '>=' );
3296	case 'set_charset' :
3297	return version_compare( $version, '5.0.7', '>=' );
3298	case 'utf8mb4' : // @since 4.1.0
3299	if ( version_compare( $version, '5.5.3', '<' ) ) {
3300	return false;
3301	}
3302	if ( $this->use_mysqli ) {
3303	$client_version = mysqli_get_client_info();
3304	} else {
3305	$client_version = mysql_get_client_info();
3306	}
3307
3308	/*
3309	* libmysql has supported utf8mb4 since 5.5.3, same as the MySQL server.
3310	* mysqlnd has supported utf8mb4 since 5.0.9.
3311	*/
3312	if ( false !== strpos( $client_version, 'mysqlnd' ) ) {
3313	$client_version = preg_replace( '/^\D+([\d.]+).*/', '$1', $client_version );
3314	return version_compare( $client_version, '5.0.9', '>=' );
3315	} else {
3316	return version_compare( $client_version, '5.5.3', '>=' );
3317	}
3318	case 'utf8mb4_520' : // @since 4.6.0
3319	return version_compare( $version, '5.6', '>=' );
3320	}
3321
3322	return false;
3323	}
3324
3325	/**
3326	* Retrieve the name of the function that called wpdb.
3327	*
3328	* Searches up the list of functions until it reaches
3329	* the one that would most logically had called this method.
3330	*
3331	* @since 2.5.0
3332	*
3333	* @return string\|array The name of the calling function
3334	*/
3335	public function get_caller() {
3336	return wp_debug_backtrace_summary( __CLASS__ );
3337	}
3338
3339	/**
3340	* Retrieves the MySQL server version.
3341	*
3342	* @since 2.7.0
3343	*
3344	* @return null\|string Null on failure, version number on success.
3345	*/
3346	public function db_version() {
3347	if ( $this->use_mysqli ) {
3348	$server_info = mysqli_get_server_info( $this->dbh );
3349	} else {
3350	$server_info = mysql_get_server_info( $this->dbh );
3351	}
3352	return preg_replace( '/[^0-9.].*/', '', $server_info );
3353	}
3354	}

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Ticket #41956: wp-db.php

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