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/wp-includes/ -> class-wpdb.php (source)

   1  <?php
   2  /**
   3   * WordPress database access abstraction class.
   4   *
   5   * Original code from {@link http://php.justinvincent.com Justin Vincent (justin@visunet.ie)}
   6   *
   7   * @package WordPress
   8   * @subpackage Database
   9   * @since 0.71
  10   */
  11  
  12  /**
  13   * @since 0.71
  14   */
  15  define( 'EZSQL_VERSION', 'WP1.25' );
  16  
  17  /**
  18   * @since 0.71
  19   */
  20  define( 'OBJECT', 'OBJECT' );
  21  // phpcs:ignore Generic.NamingConventions.UpperCaseConstantName.ConstantNotUpperCase
  22  define( 'object', 'OBJECT' ); // Back compat.
  23  
  24  /**
  25   * @since 2.5.0
  26   */
  27  define( 'OBJECT_K', 'OBJECT_K' );
  28  
  29  /**
  30   * @since 0.71
  31   */
  32  define( 'ARRAY_A', 'ARRAY_A' );
  33  
  34  /**
  35   * @since 0.71
  36   */
  37  define( 'ARRAY_N', 'ARRAY_N' );
  38  
  39  /**
  40   * WordPress database access abstraction class.
  41   *
  42   * This class is used to interact with a database without needing to use raw SQL statements.
  43   * By default, WordPress uses this class to instantiate the global $wpdb object, providing
  44   * access to the WordPress database.
  45   *
  46   * It is possible to replace the global instance with your own by setting the $wpdb global variable
  47   * in wp-content/db.php file to your class. The wpdb class will still be included, so you can
  48   * extend it or simply use your own.
  49   *
  50   * @link https://developer.wordpress.org/reference/classes/wpdb/
  51   *
  52   * @since 0.71
  53   */
  54  #[AllowDynamicProperties]
  55  class wpdb {
  56  
  57      /**
  58       * Whether to show SQL/DB errors.
  59       *
  60       * Default is to show errors if both WP_DEBUG and WP_DEBUG_DISPLAY evaluate to true.
  61       *
  62       * @since 0.71
  63       *
  64       * @var bool
  65       */
  66      public $show_errors = false;
  67  
  68      /**
  69       * Whether to suppress errors during the DB bootstrapping. Default false.
  70       *
  71       * @since 2.5.0
  72       *
  73       * @var bool
  74       */
  75      public $suppress_errors = false;
  76  
  77      /**
  78       * The error encountered during the last query.
  79       *
  80       * @since 2.5.0
  81       *
  82       * @var string
  83       */
  84      public $last_error = '';
  85  
  86      /**
  87       * The number of queries made.
  88       *
  89       * @since 1.2.0
  90       *
  91       * @var int
  92       */
  93      public $num_queries = 0;
  94  
  95      /**
  96       * Count of rows returned by the last query.
  97       *
  98       * @since 0.71
  99       *
 100       * @var int
 101       */
 102      public $num_rows = 0;
 103  
 104      /**
 105       * Count of rows affected by the last query.
 106       *
 107       * @since 0.71
 108       *
 109       * @var int
 110       */
 111      public $rows_affected = 0;
 112  
 113      /**
 114       * The ID generated for an AUTO_INCREMENT column by the last query (usually INSERT).
 115       *
 116       * @since 0.71
 117       *
 118       * @var int
 119       */
 120      public $insert_id = 0;
 121  
 122      /**
 123       * The last query made.
 124       *
 125       * @since 0.71
 126       *
 127       * @var string
 128       */
 129      public $last_query;
 130  
 131      /**
 132       * Results of the last query.
 133       *
 134       * @since 0.71
 135       *
 136       * @var stdClass[]|null
 137       */
 138      public $last_result;
 139  
 140      /**
 141       * Database query result.
 142       *
 143       * Possible values:
 144       *
 145       * - `mysqli_result` instance for successful SELECT, SHOW, DESCRIBE, or EXPLAIN queries
 146       * - `true` for other query types that were successful
 147       * - `null` if a query is yet to be made or if the result has since been flushed
 148       * - `false` if the query returned an error
 149       *
 150       * @since 0.71
 151       *
 152       * @var mysqli_result|bool|null
 153       */
 154      protected $result;
 155  
 156      /**
 157       * Cached column info, for confidence checking data before inserting.
 158       *
 159       * @since 4.2.0
 160       *
 161       * @var array
 162       */
 163      protected $col_meta = array();
 164  
 165      /**
 166       * Calculated character sets keyed by table name.
 167       *
 168       * @since 4.2.0
 169       *
 170       * @var string[]
 171       */
 172      protected $table_charset = array();
 173  
 174      /**
 175       * Whether text fields in the current query need to be confidence checked.
 176       *
 177       * @since 4.2.0
 178       *
 179       * @var bool
 180       */
 181      protected $check_current_query = true;
 182  
 183      /**
 184       * Flag to ensure we don't run into recursion problems when checking the collation.
 185       *
 186       * @since 4.2.0
 187       *
 188       * @see wpdb::check_safe_collation()
 189       * @var bool
 190       */
 191      private $checking_collation = false;
 192  
 193      /**
 194       * Saved info on the table column.
 195       *
 196       * @since 0.71
 197       *
 198       * @var array
 199       */
 200      protected $col_info;
 201  
 202      /**
 203       * Log of queries that were executed, for debugging purposes.
 204       *
 205       * @since 1.5.0
 206       * @since 2.5.0 The third element in each query log was added to record the calling functions.
 207       * @since 5.1.0 The fourth element in each query log was added to record the start time.
 208       * @since 5.3.0 The fifth element in each query log was added to record custom data.
 209       *
 210       * @var array[] {
 211       *     Array of arrays containing information about queries that were executed.
 212       *
 213       *     @type array ...$0 {
 214       *         Data for each query.
 215       *
 216       *         @type string $0 The query's SQL.
 217       *         @type float  $1 Total time spent on the query, in seconds.
 218       *         @type string $2 Comma-separated list of the calling functions.
 219       *         @type float  $3 Unix timestamp of the time at the start of the query.
 220       *         @type array  $4 Custom query data.
 221       *     }
 222       * }
 223       */
 224      public $queries;
 225  
 226      /**
 227       * The number of times to retry reconnecting before dying. Default 5.
 228       *
 229       * @since 3.9.0
 230       *
 231       * @see wpdb::check_connection()
 232       * @var int
 233       */
 234      protected $reconnect_retries = 5;
 235  
 236      /**
 237       * WordPress table prefix.
 238       *
 239       * You can set this to have multiple WordPress installations in a single database.
 240       *
 241       * @since 2.5.0
 242       *
 243       * @var string
 244       */
 245      public $prefix = '';
 246  
 247      /**
 248       * WordPress base table prefix.
 249       *
 250       * @since 3.0.0
 251       *
 252       * @var string
 253       */
 254      public $base_prefix;
 255  
 256      /**
 257       * Whether the database queries are ready to start executing.
 258       *
 259       * @since 2.3.2
 260       *
 261       * @var bool
 262       */
 263      public $ready = false;
 264  
 265      /**
 266       * Blog ID.
 267       *
 268       * @since 3.0.0
 269       *
 270       * @var int
 271       */
 272      public $blogid = 0;
 273  
 274      /**
 275       * Site ID.
 276       *
 277       * @since 3.0.0
 278       *
 279       * @var int
 280       */
 281      public $siteid = 0;
 282  
 283      /**
 284       * List of WordPress per-site tables.
 285       *
 286       * @since 2.5.0
 287       *
 288       * @see wpdb::tables()
 289       * @var string[]
 290       */
 291      public $tables = array(
 292          'posts',
 293          'comments',
 294          'links',
 295          'options',
 296          'postmeta',
 297          'terms',
 298          'term_taxonomy',
 299          'term_relationships',
 300          'termmeta',
 301          'commentmeta',
 302      );
 303  
 304      /**
 305       * List of deprecated WordPress tables.
 306       *
 307       * 'categories', 'post2cat', and 'link2cat' were deprecated in 2.3.0, db version 5539.
 308       *
 309       * @since 2.9.0
 310       *
 311       * @see wpdb::tables()
 312       * @var string[]
 313       */
 314      public $old_tables = array( 'categories', 'post2cat', 'link2cat' );
 315  
 316      /**
 317       * List of WordPress global tables.
 318       *
 319       * @since 3.0.0
 320       *
 321       * @see wpdb::tables()
 322       * @var string[]
 323       */
 324      public $global_tables = array( 'users', 'usermeta' );
 325  
 326      /**
 327       * List of Multisite global tables.
 328       *
 329       * @since 3.0.0
 330       *
 331       * @see wpdb::tables()
 332       * @var string[]
 333       */
 334      public $ms_global_tables = array(
 335          'blogs',
 336          'blogmeta',
 337          'signups',
 338          'site',
 339          'sitemeta',
 340          'registration_log',
 341      );
 342  
 343      /**
 344       * List of deprecated WordPress Multisite global tables.
 345       *
 346       * @since 6.1.0
 347       *
 348       * @see wpdb::tables()
 349       * @var string[]
 350       */
 351      public $old_ms_global_tables = array( 'sitecategories' );
 352  
 353      /**
 354       * WordPress Comments table.
 355       *
 356       * @since 1.5.0
 357       *
 358       * @var string
 359       */
 360      public $comments;
 361  
 362      /**
 363       * WordPress Comment Metadata table.
 364       *
 365       * @since 2.9.0
 366       *
 367       * @var string
 368       */
 369      public $commentmeta;
 370  
 371      /**
 372       * WordPress Links table.
 373       *
 374       * @since 1.5.0
 375       *
 376       * @var string
 377       */
 378      public $links;
 379  
 380      /**
 381       * WordPress Options table.
 382       *
 383       * @since 1.5.0
 384       *
 385       * @var string
 386       */
 387      public $options;
 388  
 389      /**
 390       * WordPress Post Metadata table.
 391       *
 392       * @since 1.5.0
 393       *
 394       * @var string
 395       */
 396      public $postmeta;
 397  
 398      /**
 399       * WordPress Posts table.
 400       *
 401       * @since 1.5.0
 402       *
 403       * @var string
 404       */
 405      public $posts;
 406  
 407      /**
 408       * WordPress Terms table.
 409       *
 410       * @since 2.3.0
 411       *
 412       * @var string
 413       */
 414      public $terms;
 415  
 416      /**
 417       * WordPress Term Relationships table.
 418       *
 419       * @since 2.3.0
 420       *
 421       * @var string
 422       */
 423      public $term_relationships;
 424  
 425      /**
 426       * WordPress Term Taxonomy table.
 427       *
 428       * @since 2.3.0
 429       *
 430       * @var string
 431       */
 432      public $term_taxonomy;
 433  
 434      /**
 435       * WordPress Term Meta table.
 436       *
 437       * @since 4.4.0
 438       *
 439       * @var string
 440       */
 441      public $termmeta;
 442  
 443      //
 444      // Global and Multisite tables
 445      //
 446  
 447      /**
 448       * WordPress User Metadata table.
 449       *
 450       * @since 2.3.0
 451       *
 452       * @var string
 453       */
 454      public $usermeta;
 455  
 456      /**
 457       * WordPress Users table.
 458       *
 459       * @since 1.5.0
 460       *
 461       * @var string
 462       */
 463      public $users;
 464  
 465      /**
 466       * Multisite Blogs table.
 467       *
 468       * @since 3.0.0
 469       *
 470       * @var string|null
 471       */
 472      public $blogs;
 473  
 474      /**
 475       * Multisite Blog Metadata table.
 476       *
 477       * @since 5.1.0
 478       *
 479       * @var string|null
 480       */
 481      public $blogmeta;
 482  
 483      /**
 484       * Multisite Registration Log table.
 485       *
 486       * @since 3.0.0
 487       *
 488       * @var string|null
 489       */
 490      public $registration_log;
 491  
 492      /**
 493       * Multisite Signups table.
 494       *
 495       * @since 3.0.0
 496       *
 497       * @var string|null
 498       */
 499      public $signups;
 500  
 501      /**
 502       * Multisite Sites table.
 503       *
 504       * @since 3.0.0
 505       *
 506       * @var string|null
 507       */
 508      public $site;
 509  
 510      /**
 511       * Multisite Sitewide Terms table.
 512       *
 513       * @since 3.0.0
 514       *
 515       * @var string|null
 516       */
 517      public $sitecategories;
 518  
 519      /**
 520       * Multisite Site Metadata table.
 521       *
 522       * @since 3.0.0
 523       *
 524       * @var string|null
 525       */
 526      public $sitemeta;
 527  
 528      /**
 529       * Format specifiers for DB columns.
 530       *
 531       * Columns not listed here default to %s. Initialized during WP load.
 532       * Keys are column names, values are format types: 'ID' => '%d'.
 533       *
 534       * @since 2.8.0
 535       *
 536       * @see wpdb::prepare()
 537       * @see wpdb::insert()
 538       * @see wpdb::update()
 539       * @see wpdb::delete()
 540       * @see wp_set_wpdb_vars()
 541       * @var array
 542       */
 543      public $field_types = array();
 544  
 545      /**
 546       * Database table columns charset.
 547       *
 548       * @since 2.2.0
 549       *
 550       * @var string
 551       */
 552      public $charset;
 553  
 554      /**
 555       * Database table columns collate.
 556       *
 557       * @since 2.2.0
 558       *
 559       * @var string
 560       */
 561      public $collate;
 562  
 563      /**
 564       * Database Username.
 565       *
 566       * @since 2.9.0
 567       *
 568       * @var string
 569       */
 570      protected $dbuser;
 571  
 572      /**
 573       * Database Password.
 574       *
 575       * @since 3.1.0
 576       *
 577       * @var string
 578       */
 579      protected $dbpassword;
 580  
 581      /**
 582       * Database Name.
 583       *
 584       * @since 3.1.0
 585       *
 586       * @var string
 587       */
 588      protected $dbname;
 589  
 590      /**
 591       * Database Host.
 592       *
 593       * @since 3.1.0
 594       *
 595       * @var string
 596       */
 597      protected $dbhost;
 598  
 599      /**
 600       * Database handle.
 601       *
 602       * Possible values:
 603       *
 604       * - `mysqli` instance during normal operation
 605       * - `null` if the connection is yet to be made or has been closed
 606       * - `false` if the connection has failed
 607       *
 608       * @since 0.71
 609       *
 610       * @var mysqli|false|null
 611       */
 612      protected $dbh;
 613  
 614      /**
 615       * A textual description of the last query/get_row/get_var call.
 616       *
 617       * @since 3.0.0
 618       *
 619       * @var string
 620       */
 621      public $func_call;
 622  
 623      /**
 624       * Whether MySQL is used as the database engine.
 625       *
 626       * Set in wpdb::db_connect() to true, by default. This is used when checking
 627       * against the required MySQL version for WordPress. Normally, a replacement
 628       * database drop-in (db.php) will skip these checks, but setting this to true
 629       * will force the checks to occur.
 630       *
 631       * @since 3.3.0
 632       *
 633       * @var bool
 634       */
 635      public $is_mysql = null;
 636  
 637      /**
 638       * A list of incompatible SQL modes.
 639       *
 640       * @since 3.9.0
 641       *
 642       * @var string[]
 643       */
 644      protected $incompatible_modes = array(
 645          'NO_ZERO_DATE',
 646          'ONLY_FULL_GROUP_BY',
 647          'STRICT_TRANS_TABLES',
 648          'STRICT_ALL_TABLES',
 649          'TRADITIONAL',
 650          'ANSI',
 651      );
 652  
 653      /**
 654       * Backward compatibility, where wpdb::prepare() has not quoted formatted/argnum placeholders.
 655       *
 656       * This is often used for table/field names (before %i was supported), and sometimes string formatting, e.g.
 657       *
 658       *     $wpdb->prepare( 'WHERE `%1$s` = "%2$s something %3$s" OR %1$s = "%4$-10s"', 'field_1', 'a', 'b', 'c' );
 659       *
 660       * But it's risky, e.g. forgetting to add quotes, resulting in SQL Injection vulnerabilities:
 661       *
 662       *     $wpdb->prepare( 'WHERE (id = %1s) OR (id = %2$s)', $_GET['id'], $_GET['id'] ); // ?id=id
 663       *
 664       * This feature is preserved while plugin authors update their code to use safer approaches:
 665       *
 666       *     $_GET['key'] = 'a`b';
 667       *
 668       *     $wpdb->prepare( 'WHERE %1s = %s',        $_GET['key'], $_GET['value'] ); // WHERE a`b = 'value'
 669       *     $wpdb->prepare( 'WHERE `%1$s` = "%2$s"', $_GET['key'], $_GET['value'] ); // WHERE `a`b` = "value"
 670       *
 671       *     $wpdb->prepare( 'WHERE %i = %s',         $_GET['key'], $_GET['value'] ); // WHERE `a``b` = 'value'
 672       *
 673       * While changing to false will be fine for queries not using formatted/argnum placeholders,
 674       * any remaining cases are most likely going to result in SQL errors (good, in a way):
 675       *
 676       *     $wpdb->prepare( 'WHERE %1$s = "%2$-10s"', 'my_field', 'my_value' );
 677       *     true  = WHERE my_field = "my_value  "
 678       *     false = WHERE 'my_field' = "'my_value  '"
 679       *
 680       * But there may be some queries that result in an SQL Injection vulnerability:
 681       *
 682       *     $wpdb->prepare( 'WHERE id = %1$s', $_GET['id'] ); // ?id=id
 683       *
 684       * So there may need to be a `_doing_it_wrong()` phase, after we know everyone can use
 685       * identifier placeholders (%i), but before this feature is disabled or removed.
 686       *
 687       * @since 6.2.0
 688       * @var bool
 689       */
 690      private $allow_unsafe_unquoted_parameters = true;
 691  
 692      /**
 693       * Whether to use the mysqli extension over mysql. This is no longer used as the mysql
 694       * extension is no longer supported.
 695       *
 696       * Default true.
 697       *
 698       * @since 3.9.0
 699       * @since 6.4.0 This property was removed.
 700       * @since 6.4.1 This property was reinstated and its default value was changed to true.
 701       *              The property is no longer used in core but may be accessed externally.
 702       *
 703       * @var bool
 704       */
 705      private $use_mysqli = true;
 706  
 707      /**
 708       * Whether we've managed to successfully connect at some point.
 709       *
 710       * @since 3.9.0
 711       *
 712       * @var bool
 713       */
 714      private $has_connected = false;
 715  
 716      /**
 717       * Time when the last query was performed.
 718       *
 719       * Only set when `SAVEQUERIES` is defined and truthy.
 720       *
 721       * @since 1.5.0
 722       *
 723       * @var float
 724       */
 725      public $time_start = null;
 726  
 727      /**
 728       * The last SQL error that was encountered.
 729       *
 730       * @since 2.5.0
 731       *
 732       * @var WP_Error|string
 733       */
 734      public $error = null;
 735  
 736      /**
 737       * Connects to the database server and selects a database.
 738       *
 739       * Does the actual setting up
 740       * of the class properties and connection to the database.
 741       *
 742       * @since 2.0.8
 743       *
 744       * @link https://core.trac.wordpress.org/ticket/3354
 745       *
 746       * @param string $dbuser     Database user.
 747       * @param string $dbpassword Database password.
 748       * @param string $dbname     Database name.
 749       * @param string $dbhost     Database host.
 750       */
 751  	public function __construct(
 752          $dbuser,
 753          #[\SensitiveParameter]
 754          $dbpassword,
 755          $dbname,
 756          $dbhost
 757      ) {
 758          if ( WP_DEBUG && WP_DEBUG_DISPLAY ) {
 759              $this->show_errors();
 760          }
 761  
 762          $this->dbuser     = $dbuser;
 763          $this->dbpassword = $dbpassword;
 764          $this->dbname     = $dbname;
 765          $this->dbhost     = $dbhost;
 766  
 767          // wp-config.php creation will manually connect when ready.
 768          if ( defined( 'WP_SETUP_CONFIG' ) ) {
 769              return;
 770          }
 771  
 772          $this->db_connect();
 773      }
 774  
 775      /**
 776       * Makes private properties readable for backward compatibility.
 777       *
 778       * @since 3.5.0
 779       *
 780       * @param string $name The private member to get, and optionally process.
 781       * @return mixed The private member.
 782       */
 783  	public function __get( $name ) {
 784          if ( 'col_info' === $name ) {
 785              $this->load_col_info();
 786          }
 787  
 788          return $this->$name;
 789      }
 790  
 791      /**
 792       * Makes private properties settable for backward compatibility.
 793       *
 794       * @since 3.5.0
 795       *
 796       * @param string $name  The private member to set.
 797       * @param mixed  $value The value to set.
 798       */
 799  	public function __set( $name, $value ) {
 800          $protected_members = array(
 801              'col_meta',
 802              'table_charset',
 803              'check_current_query',
 804              'allow_unsafe_unquoted_parameters',
 805          );
 806          if ( in_array( $name, $protected_members, true ) ) {
 807              return;
 808          }
 809          $this->$name = $value;
 810      }
 811  
 812      /**
 813       * Makes private properties check-able for backward compatibility.
 814       *
 815       * @since 3.5.0
 816       *
 817       * @param string $name The private member to check.
 818       * @return bool If the member is set or not.
 819       */
 820  	public function __isset( $name ) {
 821          return isset( $this->$name );
 822      }
 823  
 824      /**
 825       * Makes private properties un-settable for backward compatibility.
 826       *
 827       * @since 3.5.0
 828       *
 829       * @param string $name The private member to unset.
 830       */
 831  	public function __unset( $name ) {
 832          unset( $this->$name );
 833      }
 834  
 835      /**
 836       * Sets $this->charset and $this->collate.
 837       *
 838       * @since 3.1.0
 839       */
 840  	public function init_charset() {
 841          $charset = '';
 842          $collate = '';
 843  
 844          if ( function_exists( 'is_multisite' ) && is_multisite() ) {
 845              $charset = 'utf8';
 846              if ( defined( 'DB_COLLATE' ) && DB_COLLATE ) {
 847                  $collate = DB_COLLATE;
 848              } else {
 849                  $collate = 'utf8_general_ci';
 850              }
 851          } elseif ( defined( 'DB_COLLATE' ) ) {
 852              $collate = DB_COLLATE;
 853          }
 854  
 855          if ( defined( 'DB_CHARSET' ) ) {
 856              $charset = DB_CHARSET;
 857          }
 858  
 859          $charset_collate = $this->determine_charset( $charset, $collate );
 860  
 861          $this->charset = $charset_collate['charset'];
 862          $this->collate = $charset_collate['collate'];
 863      }
 864  
 865      /**
 866       * Determines the best charset and collation to use given a charset and collation.
 867       *
 868       * For example, when able, utf8mb4 should be used instead of utf8.
 869       *
 870       * @since 4.6.0
 871       *
 872       * @param string $charset The character set to check.
 873       * @param string $collate The collation to check.
 874       * @return array {
 875       *     The most appropriate character set and collation to use.
 876       *
 877       *     @type string $charset Character set.
 878       *     @type string $collate Collation.
 879       * }
 880       */
 881  	public function determine_charset( $charset, $collate ) {
 882          if ( ( ! ( $this->dbh instanceof mysqli ) ) || empty( $this->dbh ) ) {
 883              return compact( 'charset', 'collate' );
 884          }
 885  
 886          if ( 'utf8' === $charset ) {
 887              $charset = 'utf8mb4';
 888          }
 889  
 890          if ( 'utf8mb4' === $charset ) {
 891              // _general_ is outdated, so we can upgrade it to _unicode_, instead.
 892              if ( ! $collate || 'utf8_general_ci' === $collate ) {
 893                  $collate = 'utf8mb4_unicode_ci';
 894              } else {
 895                  $collate = str_replace( 'utf8_', 'utf8mb4_', $collate );
 896              }
 897          }
 898  
 899          // _unicode_520_ is a better collation, we should use that when it's available.
 900          if ( $this->has_cap( 'utf8mb4_520' ) && 'utf8mb4_unicode_ci' === $collate ) {
 901              $collate = 'utf8mb4_unicode_520_ci';
 902          }
 903  
 904          return compact( 'charset', 'collate' );
 905      }
 906  
 907      /**
 908       * Sets the connection's character set.
 909       *
 910       * @since 3.1.0
 911       *
 912       * @param mysqli $dbh     The connection returned by `mysqli_connect()`.
 913       * @param string $charset Optional. The character set. Default null.
 914       * @param string $collate Optional. The collation. Default null.
 915       */
 916  	public function set_charset( $dbh, $charset = null, $collate = null ) {
 917          if ( ! isset( $charset ) ) {
 918              $charset = $this->charset;
 919          }
 920          if ( ! isset( $collate ) ) {
 921              $collate = $this->collate;
 922          }
 923          if ( $this->has_cap( 'collation' ) && ! empty( $charset ) ) {
 924              $set_charset_succeeded = true;
 925  
 926              if ( function_exists( 'mysqli_set_charset' ) && $this->has_cap( 'set_charset' ) ) {
 927                  $set_charset_succeeded = mysqli_set_charset( $dbh, $charset );
 928              }
 929  
 930              if ( $set_charset_succeeded ) {
 931                  $query = $this->prepare( 'SET NAMES %s', $charset );
 932                  if ( ! empty( $collate ) ) {
 933                      $query .= $this->prepare( ' COLLATE %s', $collate );
 934                  }
 935                  mysqli_query( $dbh, $query );
 936              }
 937          }
 938      }
 939  
 940      /**
 941       * Changes the current SQL mode, and ensures its WordPress compatibility.
 942       *
 943       * If no modes are passed, it will ensure the current SQL server modes are compatible.
 944       *
 945       * @since 3.9.0
 946       *
 947       * @param array $modes Optional. A list of SQL modes to set. Default empty array.
 948       */
 949  	public function set_sql_mode( $modes = array() ) {
 950          if ( empty( $modes ) ) {
 951              $res = mysqli_query( $this->dbh, 'SELECT @@SESSION.sql_mode' );
 952  
 953              if ( empty( $res ) ) {
 954                  return;
 955              }
 956  
 957              $modes_array = mysqli_fetch_array( $res );
 958  
 959              if ( empty( $modes_array[0] ) ) {
 960                  return;
 961              }
 962  
 963              $modes = explode( ',', $modes_array[0] );
 964          }
 965  
 966          $modes = array_change_key_case( $modes, CASE_UPPER );
 967  
 968          /**
 969           * Filters the list of incompatible SQL modes to exclude.
 970           *
 971           * @since 3.9.0
 972           *
 973           * @param array $incompatible_modes An array of incompatible modes.
 974           */
 975          $incompatible_modes = (array) apply_filters( 'incompatible_sql_modes', $this->incompatible_modes );
 976  
 977          foreach ( $modes as $i => $mode ) {
 978              if ( in_array( $mode, $incompatible_modes, true ) ) {
 979                  unset( $modes[ $i ] );
 980              }
 981          }
 982  
 983          $modes_str = implode( ',', $modes );
 984  
 985          mysqli_query( $this->dbh, "SET SESSION sql_mode='$modes_str'" );
 986      }
 987  
 988      /**
 989       * Sets the table prefix for the WordPress tables.
 990       *
 991       * @since 2.5.0
 992       *
 993       * @param string $prefix          Alphanumeric name for the new prefix.
 994       * @param bool   $set_table_names Optional. Whether the table names, e.g. wpdb::$posts,
 995       *                                should be updated or not. Default true.
 996       * @return string|WP_Error Old prefix or WP_Error on error.
 997       */
 998  	public function set_prefix( $prefix, $set_table_names = true ) {
 999  
1000          if ( preg_match( '|[^a-z0-9_]|i', $prefix ) ) {
1001              return new WP_Error( 'invalid_db_prefix', 'Invalid database prefix' );
1002          }
1003  
1004          $old_prefix = is_multisite() ? '' : $prefix;
1005  
1006          if ( isset( $this->base_prefix ) ) {
1007              $old_prefix = $this->base_prefix;
1008          }
1009  
1010          $this->base_prefix = $prefix;
1011  
1012          if ( $set_table_names ) {
1013              foreach ( $this->tables( 'global' ) as $table => $prefixed_table ) {
1014                  $this->$table = $prefixed_table;
1015              }
1016  
1017              if ( is_multisite() && empty( $this->blogid ) ) {
1018                  return $old_prefix;
1019              }
1020  
1021              $this->prefix = $this->get_blog_prefix();
1022  
1023              foreach ( $this->tables( 'blog' ) as $table => $prefixed_table ) {
1024                  $this->$table = $prefixed_table;
1025              }
1026  
1027              foreach ( $this->tables( 'old' ) as $table => $prefixed_table ) {
1028                  $this->$table = $prefixed_table;
1029              }
1030          }
1031          return $old_prefix;
1032      }
1033  
1034      /**
1035       * Sets blog ID.
1036       *
1037       * @since 3.0.0
1038       *
1039       * @param int $blog_id
1040       * @param int $network_id Optional. Network ID. Default 0.
1041       * @return int Previous blog ID.
1042       */
1043  	public function set_blog_id( $blog_id, $network_id = 0 ) {
1044          if ( ! empty( $network_id ) ) {
1045              $this->siteid = $network_id;
1046          }
1047  
1048          $old_blog_id  = $this->blogid;
1049          $this->blogid = $blog_id;
1050  
1051          $this->prefix = $this->get_blog_prefix();
1052  
1053          foreach ( $this->tables( 'blog' ) as $table => $prefixed_table ) {
1054              $this->$table = $prefixed_table;
1055          }
1056  
1057          foreach ( $this->tables( 'old' ) as $table => $prefixed_table ) {
1058              $this->$table = $prefixed_table;
1059          }
1060  
1061          return $old_blog_id;
1062      }
1063  
1064      /**
1065       * Gets blog prefix.
1066       *
1067       * @since 3.0.0
1068       *
1069       * @param int $blog_id Optional. Blog ID to retrieve the table prefix for.
1070       *                     Defaults to the current blog ID.
1071       * @return string Blog prefix.
1072       */
1073  	public function get_blog_prefix( $blog_id = null ) {
1074          if ( is_multisite() ) {
1075              if ( null === $blog_id ) {
1076                  $blog_id = $this->blogid;
1077              }
1078  
1079              $blog_id = (int) $blog_id;
1080  
1081              if ( defined( 'MULTISITE' ) && ( 0 === $blog_id || 1 === $blog_id ) ) {
1082                  return $this->base_prefix;
1083              } else {
1084                  return $this->base_prefix . $blog_id . '_';
1085              }
1086          } else {
1087              return $this->base_prefix;
1088          }
1089      }
1090  
1091      /**
1092       * Returns an array of WordPress tables.
1093       *
1094       * Also allows for the `CUSTOM_USER_TABLE` and `CUSTOM_USER_META_TABLE` to override the WordPress users
1095       * and usermeta tables that would otherwise be determined by the prefix.
1096       *
1097       * The `$scope` argument can take one of the following:
1098       *
1099       * - 'all' - returns 'all' and 'global' tables. No old tables are returned.
1100       * - 'blog' - returns the blog-level tables for the queried blog.
1101       * - 'global' - returns the global tables for the installation, returning multisite tables only on multisite.
1102       * - 'ms_global' - returns the multisite global tables, regardless if current installation is multisite.
1103       * - 'old' - returns tables which are deprecated.
1104       *
1105       * @since 3.0.0
1106       * @since 6.1.0 `old` now includes deprecated multisite global tables only on multisite.
1107       *
1108       * @uses wpdb::$tables
1109       * @uses wpdb::$old_tables
1110       * @uses wpdb::$global_tables
1111       * @uses wpdb::$ms_global_tables
1112       * @uses wpdb::$old_ms_global_tables
1113       *
1114       * @param string $scope   Optional. Possible values include 'all', 'global', 'ms_global', 'blog',
1115       *                        or 'old' tables. Default 'all'.
1116       * @param bool   $prefix  Optional. Whether to include table prefixes. If blog prefix is requested,
1117       *                        then the custom users and usermeta tables will be mapped. Default true.
1118       * @param int    $blog_id Optional. The blog_id to prefix. Used only when prefix is requested.
1119       *                        Defaults to `wpdb::$blogid`.
1120       * @return string[] Table names. When a prefix is requested, the key is the unprefixed table name.
1121       */
1122  	public function tables( $scope = 'all', $prefix = true, $blog_id = 0 ) {
1123          switch ( $scope ) {
1124              case 'all':
1125                  $tables = array_merge( $this->global_tables, $this->tables );
1126                  if ( is_multisite() ) {
1127                      $tables = array_merge( $tables, $this->ms_global_tables );
1128                  }
1129                  break;
1130              case 'blog':
1131                  $tables = $this->tables;
1132                  break;
1133              case 'global':
1134                  $tables = $this->global_tables;
1135                  if ( is_multisite() ) {
1136                      $tables = array_merge( $tables, $this->ms_global_tables );
1137                  }
1138                  break;
1139              case 'ms_global':
1140                  $tables = $this->ms_global_tables;
1141                  break;
1142              case 'old':
1143                  $tables = $this->old_tables;
1144                  if ( is_multisite() ) {
1145                      $tables = array_merge( $tables, $this->old_ms_global_tables );
1146                  }
1147                  break;
1148              default:
1149                  return array();
1150          }
1151  
1152          if ( $prefix ) {
1153              if ( ! $blog_id ) {
1154                  $blog_id = $this->blogid;
1155              }
1156              $blog_prefix   = $this->get_blog_prefix( $blog_id );
1157              $base_prefix   = $this->base_prefix;
1158              $global_tables = array_merge( $this->global_tables, $this->ms_global_tables );
1159              foreach ( $tables as $k => $table ) {
1160                  if ( in_array( $table, $global_tables, true ) ) {
1161                      $tables[ $table ] = $base_prefix . $table;
1162                  } else {
1163                      $tables[ $table ] = $blog_prefix . $table;
1164                  }
1165                  unset( $tables[ $k ] );
1166              }
1167  
1168              if ( isset( $tables['users'] ) && defined( 'CUSTOM_USER_TABLE' ) ) {
1169                  $tables['users'] = CUSTOM_USER_TABLE;
1170              }
1171  
1172              if ( isset( $tables['usermeta'] ) && defined( 'CUSTOM_USER_META_TABLE' ) ) {
1173                  $tables['usermeta'] = CUSTOM_USER_META_TABLE;
1174              }
1175          }
1176  
1177          return $tables;
1178      }
1179  
1180      /**
1181       * Selects a database using the current or provided database connection.
1182       *
1183       * The database name will be changed based on the current database connection.
1184       * On failure, the execution will bail and display a DB error.
1185       *
1186       * @since 0.71
1187       *
1188       * @param string $db  Database name.
1189       * @param mysqli $dbh Optional. Database connection.
1190       *                    Defaults to the current database handle.
1191       */
1192  	public function select( $db, $dbh = null ) {
1193          if ( is_null( $dbh ) ) {
1194              $dbh = $this->dbh;
1195          }
1196  
1197          $success = mysqli_select_db( $dbh, $db );
1198  
1199          if ( ! $success ) {
1200              $this->ready = false;
1201              if ( ! did_action( 'template_redirect' ) ) {
1202                  wp_load_translations_early();
1203  
1204                  $message = '<h1>' . __( 'Cannot select database' ) . "</h1>\n";
1205  
1206                  $message .= '<p>' . sprintf(
1207                      /* translators: %s: Database name. */
1208                      __( 'The database server could be connected to (which means your username and password is okay) but the %s database could not be selected.' ),
1209                      '<code>' . htmlspecialchars( $db, ENT_QUOTES ) . '</code>'
1210                  ) . "</p>\n";
1211  
1212                  $message .= "<ul>\n";
1213                  $message .= '<li>' . __( 'Are you sure it exists?' ) . "</li>\n";
1214  
1215                  $message .= '<li>' . sprintf(
1216                      /* translators: 1: Database user, 2: Database name. */
1217                      __( 'Does the user %1$s have permission to use the %2$s database?' ),
1218                      '<code>' . htmlspecialchars( $this->dbuser, ENT_QUOTES ) . '</code>',
1219                      '<code>' . htmlspecialchars( $db, ENT_QUOTES ) . '</code>'
1220                  ) . "</li>\n";
1221  
1222                  $message .= '<li>' . sprintf(
1223                      /* translators: %s: Database name. */
1224                      __( 'On some systems the name of your database is prefixed with your username, so it would be like <code>username_%1$s</code>. Could that be the problem?' ),
1225                      htmlspecialchars( $db, ENT_QUOTES )
1226                  ) . "</li>\n";
1227  
1228                  $message .= "</ul>\n";
1229  
1230                  $message .= '<p>' . sprintf(
1231                      /* translators: %s: Support forums URL. */
1232                      __( 'If you do not know how to set up a database you should <strong>contact your host</strong>. If all else fails you may find help at the <a href="%s">WordPress support forums</a>.' ),
1233                      __( 'https://wordpress.org/support/forums/' )
1234                  ) . "</p>\n";
1235  
1236                  $this->bail( $message, 'db_select_fail' );
1237              }
1238          }
1239      }
1240  
1241      /**
1242       * Do not use, deprecated.
1243       *
1244       * Use esc_sql() or wpdb::prepare() instead.
1245       *
1246       * @since 2.8.0
1247       * @deprecated 3.6.0 Use wpdb::prepare()
1248       * @see wpdb::prepare()
1249       * @see esc_sql()
1250       *
1251       * @param string $data
1252       * @return string
1253       */
1254  	public function _weak_escape( $data ) {
1255          if ( func_num_args() === 1 && function_exists( '_deprecated_function' ) ) {
1256              _deprecated_function( __METHOD__, '3.6.0', 'wpdb::prepare() or esc_sql()' );
1257          }
1258          return addslashes( $data );
1259      }
1260  
1261      /**
1262       * Real escape using mysqli_real_escape_string().
1263       *
1264       * @since 2.8.0
1265       *
1266       * @see mysqli_real_escape_string()
1267       *
1268       * @param string $data String to escape.
1269       * @return string Escaped string.
1270       */
1271  	public function _real_escape( $data ) {
1272          if ( ! is_scalar( $data ) ) {
1273              return '';
1274          }
1275  
1276          if ( $this->dbh ) {
1277              $escaped = mysqli_real_escape_string( $this->dbh, $data );
1278          } else {
1279              $class = get_class( $this );
1280  
1281              wp_load_translations_early();
1282              /* translators: %s: Database access abstraction class, usually wpdb or a class extending wpdb. */
1283              _doing_it_wrong( $class, sprintf( __( '%s must set a database connection for use with escaping.' ), $class ), '3.6.0' );
1284  
1285              $escaped = addslashes( $data );
1286          }
1287  
1288          return $this->add_placeholder_escape( $escaped );
1289      }
1290  
1291      /**
1292       * Escapes data. Works on arrays.
1293       *
1294       * @since 2.8.0
1295       *
1296       * @uses wpdb::_real_escape()
1297       *
1298       * @param string|array $data Data to escape.
1299       * @return string|array Escaped data, in the same type as supplied.
1300       */
1301  	public function _escape( $data ) {
1302          if ( is_array( $data ) ) {
1303              foreach ( $data as $k => $v ) {
1304                  if ( is_array( $v ) ) {
1305                      $data[ $k ] = $this->_escape( $v );
1306                  } else {
1307                      $data[ $k ] = $this->_real_escape( $v );
1308                  }
1309              }
1310          } else {
1311              $data = $this->_real_escape( $data );
1312          }
1313  
1314          return $data;
1315      }
1316  
1317      /**
1318       * Do not use, deprecated.
1319       *
1320       * Use esc_sql() or wpdb::prepare() instead.
1321       *
1322       * @since 0.71
1323       * @deprecated 3.6.0 Use wpdb::prepare()
1324       * @see wpdb::prepare()
1325       * @see esc_sql()
1326       *
1327       * @param string|array $data Data to escape.
1328       * @return string|array Escaped data, in the same type as supplied.
1329       */
1330  	public function escape( $data ) {
1331          if ( func_num_args() === 1 && function_exists( '_deprecated_function' ) ) {
1332              _deprecated_function( __METHOD__, '3.6.0', 'wpdb::prepare() or esc_sql()' );
1333          }
1334          if ( is_array( $data ) ) {
1335              foreach ( $data as $k => $v ) {
1336                  if ( is_array( $v ) ) {
1337                      $data[ $k ] = $this->escape( $v, 'recursive' );
1338                  } else {
1339                      $data[ $k ] = $this->_weak_escape( $v, 'internal' );
1340                  }
1341              }
1342          } else {
1343              $data = $this->_weak_escape( $data, 'internal' );
1344          }
1345  
1346          return $data;
1347      }
1348  
1349      /**
1350       * Escapes content by reference for insertion into the database, for security.
1351       *
1352       * @uses wpdb::_real_escape()
1353       *
1354       * @since 2.3.0
1355       *
1356       * @param string $data String to escape.
1357       */
1358  	public function escape_by_ref( &$data ) {
1359          if ( ! is_float( $data ) ) {
1360              $data = $this->_real_escape( $data );
1361          }
1362      }
1363  
1364      /**
1365       * Quotes an identifier such as a table or field name.
1366       *
1367       * @since 6.2.0
1368       *
1369       * @param string $identifier Identifier to escape.
1370       * @return string Escaped identifier.
1371       */
1372  	public function quote_identifier( $identifier ) {
1373          return '`' . $this->_escape_identifier_value( $identifier ) . '`';
1374      }
1375  
1376      /**
1377       * Escapes an identifier value without adding the surrounding quotes.
1378       *
1379       * - Permitted characters in quoted identifiers include the full Unicode
1380       *   Basic Multilingual Plane (BMP), except U+0000.
1381       * - To quote the identifier itself, you need to double the character, e.g. `a``b`.
1382       *
1383       * @since 6.2.0
1384       *
1385       * @link https://dev.mysql.com/doc/refman/8.0/en/identifiers.html
1386       *
1387       * @param string $identifier Identifier to escape.
1388       * @return string Escaped identifier.
1389       */
1390  	private function _escape_identifier_value( $identifier ) {
1391          return str_replace( '`', '``', $identifier );
1392      }
1393  
1394      /**
1395       * Prepares a SQL query for safe execution.
1396       *
1397       * Uses `sprintf()`-like syntax. The following placeholders can be used in the query string:
1398       *
1399       * - `%d` (integer)
1400       * - `%f` (float)
1401       * - `%s` (string)
1402       * - `%i` (identifier, e.g. table/field names)
1403       *
1404       * All placeholders MUST be left unquoted in the query string. A corresponding argument
1405       * MUST be passed for each placeholder.
1406       *
1407       * Note: There is one exception to the above: for compatibility with old behavior,
1408       * numbered or formatted string placeholders (eg, `%1$s`, `%5s`) will not have quotes
1409       * added by this function, so should be passed with appropriate quotes around them.
1410       *
1411       * Literal percentage signs (`%`) in the query string must be written as `%%`. Percentage wildcards
1412       * (for example, to use in LIKE syntax) must be passed via a substitution argument containing
1413       * the complete LIKE string, these cannot be inserted directly in the query string.
1414       * Also see wpdb::esc_like().
1415       *
1416       * Arguments may be passed as individual arguments to the method, or as a single array
1417       * containing all arguments. A combination of the two is not supported.
1418       *
1419       * Examples:
1420       *
1421       *     $wpdb->prepare(
1422       *         "SELECT * FROM `table` WHERE `column` = %s AND `field` = %d OR `other_field` LIKE %s",
1423       *         array( 'foo', 1337, '%bar' )
1424       *     );
1425       *
1426       *     $wpdb->prepare(
1427       *         "SELECT DATE_FORMAT(`field`, '%%c') FROM `table` WHERE `column` = %s",
1428       *         'foo'
1429       *     );
1430       *
1431       *     $wpdb->prepare(
1432       *         "SELECT * FROM %i WHERE %i = %s",
1433       *         $table,
1434       *         $field,
1435       *         $value
1436       *     );
1437       *
1438       * @since 2.3.0
1439       * @since 5.3.0 Formalized the existing and already documented `...$args` parameter
1440       *              by updating the function signature. The second parameter was changed
1441       *              from `$args` to `...$args`.
1442       * @since 6.2.0 Added `%i` for identifiers, e.g. table or field names.
1443       *              Check support via `wpdb::has_cap( 'identifier_placeholders' )`.
1444       *              This preserves compatibility with `sprintf()`, as the C version uses
1445       *              `%d` and `$i` as a signed integer, whereas PHP only supports `%d`.
1446       *
1447       * @link https://www.php.net/sprintf Description of syntax.
1448       *
1449       * @param string      $query   Query statement with `sprintf()`-like placeholders.
1450       * @param array|mixed $args    The array of variables to substitute into the query's placeholders
1451       *                             if being called with an array of arguments, or the first variable
1452       *                             to substitute into the query's placeholders if being called with
1453       *                             individual arguments.
1454       * @param mixed       ...$args Further variables to substitute into the query's placeholders
1455       *                             if being called with individual arguments.
1456       * @return string|null Sanitized query string, if there is a query to prepare.
1457       */
1458  	public function prepare( $query, ...$args ) {
1459          if ( is_null( $query ) ) {
1460              return null;
1461          }
1462  
1463          /*
1464           * This is not meant to be foolproof -- but it will catch obviously incorrect usage.
1465           *
1466           * Note: str_contains() is not used here, as this file can be included
1467           * directly outside of WordPress core, e.g. by HyperDB, in which case
1468           * the polyfills from wp-includes/compat.php are not loaded.
1469           */
1470          if ( false === strpos( $query, '%' ) ) {
1471              wp_load_translations_early();
1472              _doing_it_wrong(
1473                  'wpdb::prepare',
1474                  sprintf(
1475                      /* translators: %s: wpdb::prepare() */
1476                      __( 'The query argument of %s must have a placeholder.' ),
1477                      'wpdb::prepare()'
1478                  ),
1479                  '3.9.0'
1480              );
1481          }
1482  
1483          /*
1484           * Specify the formatting allowed in a placeholder. The following are allowed:
1485           *
1486           * - Sign specifier, e.g. $+d
1487           * - Numbered placeholders, e.g. %1$s
1488           * - Padding specifier, including custom padding characters, e.g. %05s, %'#5s
1489           * - Alignment specifier, e.g. %05-s
1490           * - Precision specifier, e.g. %.2f
1491           */
1492          $allowed_format = '(?:[1-9][0-9]*[$])?[-+0-9]*(?: |0|\'.)?[-+0-9]*(?:\.[0-9]+)?';
1493  
1494          /*
1495           * If a %s placeholder already has quotes around it, removing the existing quotes
1496           * and re-inserting them ensures the quotes are consistent.
1497           *
1498           * For backward compatibility, this is only applied to %s, and not to placeholders like %1$s,
1499           * which are frequently used in the middle of longer strings, or as table name placeholders.
1500           */
1501          $query = str_replace( "'%s'", '%s', $query ); // Strip any existing single quotes.
1502          $query = str_replace( '"%s"', '%s', $query ); // Strip any existing double quotes.
1503  
1504          // Escape any unescaped percents (i.e. anything unrecognised).
1505          $query = preg_replace( "/%(?:%|$|(?!($allowed_format)?[sdfFi]))/", '%%\\1', $query );
1506  
1507          // Extract placeholders from the query.
1508          $split_query = preg_split( "/(^|[^%]|(?:%%)+)(%(?:$allowed_format)?[sdfFi])/", $query, -1, PREG_SPLIT_DELIM_CAPTURE );
1509  
1510          $split_query_count = count( $split_query );
1511  
1512          /*
1513           * Split always returns with 1 value before the first placeholder (even with $query = "%s"),
1514           * then 3 additional values per placeholder.
1515           */
1516          $placeholder_count = ( ( $split_query_count - 1 ) / 3 );
1517  
1518          // If args were passed as an array, as in vsprintf(), move them up.
1519          $passed_as_array = ( isset( $args[0] ) && is_array( $args[0] ) && 1 === count( $args ) );
1520          if ( $passed_as_array ) {
1521              $args = $args[0];
1522          }
1523  
1524          $new_query       = '';
1525          $key             = 2; // Keys 0 and 1 in $split_query contain values before the first placeholder.
1526          $arg_id          = 0;
1527          $arg_identifiers = array();
1528          $arg_strings     = array();
1529  
1530          while ( $key < $split_query_count ) {
1531              $placeholder = $split_query[ $key ];
1532  
1533              $format = substr( $placeholder, 1, -1 );
1534              $type   = substr( $placeholder, -1 );
1535  
1536              if ( 'f' === $type && true === $this->allow_unsafe_unquoted_parameters
1537                  /*
1538                   * Note: str_ends_with() is not used here, as this file can be included
1539                   * directly outside of WordPress core, e.g. by HyperDB, in which case
1540                   * the polyfills from wp-includes/compat.php are not loaded.
1541                   */
1542                  && '%' === substr( $split_query[ $key - 1 ], -1, 1 )
1543              ) {
1544  
1545                  /*
1546                   * Before WP 6.2 the "force floats to be locale-unaware" RegEx didn't
1547                   * convert "%%%f" to "%%%F" (note the uppercase F).
1548                   * This was because it didn't check to see if the leading "%" was escaped.
1549                   * And because the "Escape any unescaped percents" RegEx used "[sdF]" in its
1550                   * negative lookahead assertion, when there was an odd number of "%", it added
1551                   * an extra "%", to give the fully escaped "%%%%f" (not a placeholder).
1552                   */
1553  
1554                  $s = $split_query[ $key - 2 ] . $split_query[ $key - 1 ];
1555                  $k = 1;
1556                  $l = strlen( $s );
1557                  while ( $k <= $l && '%' === $s[ $l - $k ] ) {
1558                      ++$k;
1559                  }
1560  
1561                  $placeholder = '%' . ( $k % 2 ? '%' : '' ) . $format . $type;
1562  
1563                  --$placeholder_count;
1564  
1565              } else {
1566  
1567                  // Force floats to be locale-unaware.
1568                  if ( 'f' === $type ) {
1569                      $type        = 'F';
1570                      $placeholder = '%' . $format . $type;
1571                  }
1572  
1573                  if ( 'i' === $type ) {
1574                      $placeholder = '`%' . $format . 's`';
1575                      // Using a simple strpos() due to previous checking (e.g. $allowed_format).
1576                      $argnum_pos = strpos( $format, '$' );
1577  
1578                      if ( false !== $argnum_pos ) {
1579                          // sprintf() argnum starts at 1, $arg_id from 0.
1580                          $arg_identifiers[] = ( ( (int) substr( $format, 0, $argnum_pos ) ) - 1 );
1581                      } else {
1582                          $arg_identifiers[] = $arg_id;
1583                      }
1584                  } elseif ( 'd' !== $type && 'F' !== $type ) {
1585                      /*
1586                       * i.e. ( 's' === $type ), where 'd' and 'F' keeps $placeholder unchanged,
1587                       * and we ensure string escaping is used as a safe default (e.g. even if 'x').
1588                       */
1589                      $argnum_pos = strpos( $format, '$' );
1590  
1591                      if ( false !== $argnum_pos ) {
1592                          $arg_strings[] = ( ( (int) substr( $format, 0, $argnum_pos ) ) - 1 );
1593                      } else {
1594                          $arg_strings[] = $arg_id;
1595                      }
1596  
1597                      /*
1598                       * Unquoted strings for backward compatibility (dangerous).
1599                       * First, "numbered or formatted string placeholders (eg, %1$s, %5s)".
1600                       * Second, if "%s" has a "%" before it, even if it's unrelated (e.g. "LIKE '%%%s%%'").
1601                       */
1602                      if ( true !== $this->allow_unsafe_unquoted_parameters
1603                          /*
1604                           * Note: str_ends_with() is not used here, as this file can be included
1605                           * directly outside of WordPress core, e.g. by HyperDB, in which case
1606                           * the polyfills from wp-includes/compat.php are not loaded.
1607                           */
1608                          || ( '' === $format && '%' !== substr( $split_query[ $key - 1 ], -1, 1 ) )
1609                      ) {
1610                          $placeholder = "'%" . $format . "s'";
1611                      }
1612                  }
1613              }
1614  
1615              // Glue (-2), any leading characters (-1), then the new $placeholder.
1616              $new_query .= $split_query[ $key - 2 ] . $split_query[ $key - 1 ] . $placeholder;
1617  
1618              $key += 3;
1619              ++$arg_id;
1620          }
1621  
1622          // Replace $query; and add remaining $query characters, or index 0 if there were no placeholders.
1623          $query = $new_query . $split_query[ $key - 2 ];
1624  
1625          $dual_use = array_intersect( $arg_identifiers, $arg_strings );
1626  
1627          if ( count( $dual_use ) > 0 ) {
1628              wp_load_translations_early();
1629  
1630              $used_placeholders = array();
1631  
1632              $key    = 2;
1633              $arg_id = 0;
1634              // Parse again (only used when there is an error).
1635              while ( $key < $split_query_count ) {
1636                  $placeholder = $split_query[ $key ];
1637  
1638                  $format = substr( $placeholder, 1, -1 );
1639  
1640                  $argnum_pos = strpos( $format, '$' );
1641  
1642                  if ( false !== $argnum_pos ) {
1643                      $arg_pos = ( ( (int) substr( $format, 0, $argnum_pos ) ) - 1 );
1644                  } else {
1645                      $arg_pos = $arg_id;
1646                  }
1647  
1648                  $used_placeholders[ $arg_pos ][] = $placeholder;
1649  
1650                  $key += 3;
1651                  ++$arg_id;
1652              }
1653  
1654              $conflicts = array();
1655              foreach ( $dual_use as $arg_pos ) {
1656                  $conflicts[] = implode( ' and ', $used_placeholders[ $arg_pos ] );
1657              }
1658  
1659              _doing_it_wrong(
1660                  'wpdb::prepare',
1661                  sprintf(
1662                      /* translators: %s: A list of placeholders found to be a problem. */
1663                      __( 'Arguments cannot be prepared as both an Identifier and Value. Found the following conflicts: %s' ),
1664                      implode( ', ', $conflicts )
1665                  ),
1666                  '6.2.0'
1667              );
1668  
1669              return null;
1670          }
1671  
1672          $args_count = count( $args );
1673  
1674          if ( $args_count !== $placeholder_count ) {
1675              if ( 1 === $placeholder_count && $passed_as_array ) {
1676                  /*
1677                   * If the passed query only expected one argument,
1678                   * but the wrong number of arguments was sent as an array, bail.
1679                   */
1680                  wp_load_translations_early();
1681                  _doing_it_wrong(
1682                      'wpdb::prepare',
1683                      __( 'The query only expected one placeholder, but an array of multiple placeholders was sent.' ),
1684                      '4.9.0'
1685                  );
1686  
1687                  return null;
1688              } else {
1689                  /*
1690                   * If we don't have the right number of placeholders,
1691                   * but they were passed as individual arguments,
1692                   * or we were expecting multiple arguments in an array, throw a warning.
1693                   */
1694                  wp_load_translations_early();
1695                  _doing_it_wrong(
1696                      'wpdb::prepare',
1697                      sprintf(
1698                          /* translators: 1: Number of placeholders, 2: Number of arguments passed. */
1699                          __( 'The query does not contain the correct number of placeholders (%1$d) for the number of arguments passed (%2$d).' ),
1700                          $placeholder_count,
1701                          $args_count
1702                      ),
1703                      '4.8.3'
1704                  );
1705  
1706                  /*
1707                   * If we don't have enough arguments to match the placeholders,
1708                   * return an empty string to avoid a fatal error on PHP 8.
1709                   */
1710                  if ( $args_count < $placeholder_count ) {
1711                      $max_numbered_placeholder = 0;
1712  
1713                      for ( $i = 2, $l = $split_query_count; $i < $l; $i += 3 ) {
1714                          // Assume a leading number is for a numbered placeholder, e.g. '%3$s'.
1715                          $argnum = (int) substr( $split_query[ $i ], 1 );
1716  
1717                          if ( $max_numbered_placeholder < $argnum ) {
1718                              $max_numbered_placeholder = $argnum;
1719                          }
1720                      }
1721  
1722                      if ( ! $max_numbered_placeholder || $args_count < $max_numbered_placeholder ) {
1723                          return '';
1724                      }
1725                  }
1726              }
1727          }
1728  
1729          $args_escaped = array();
1730  
1731          foreach ( $args as $i => $value ) {
1732              if ( in_array( $i, $arg_identifiers, true ) ) {
1733                  $args_escaped[] = $this->_escape_identifier_value( $value );
1734              } elseif ( is_int( $value ) || is_float( $value ) ) {
1735                  $args_escaped[] = $value;
1736              } else {
1737                  if ( ! is_scalar( $value ) && ! is_null( $value ) ) {
1738                      wp_load_translations_early();
1739                      _doing_it_wrong(
1740                          'wpdb::prepare',
1741                          sprintf(
1742                              /* translators: %s: Value type. */
1743                              __( 'Unsupported value type (%s).' ),
1744                              gettype( $value )
1745                          ),
1746                          '4.8.2'
1747                      );
1748  
1749                      // Preserving old behavior, where values are escaped as strings.
1750                      $value = '';
1751                  }
1752  
1753                  $args_escaped[] = $this->_real_escape( $value );
1754              }
1755          }
1756  
1757          $query = vsprintf( $query, $args_escaped );
1758  
1759          return $this->add_placeholder_escape( $query );
1760      }
1761  
1762      /**
1763       * First half of escaping for `LIKE` special characters `%` and `_` before preparing for SQL.
1764       *
1765       * Use this only before wpdb::prepare() or esc_sql(). Reversing the order is very bad for security.
1766       *
1767       * Example Prepared Statement:
1768       *
1769       *     $wild = '%';
1770       *     $find = 'only 43% of planets';
1771       *     $like = $wild . $wpdb->esc_like( $find ) . $wild;
1772       *     $sql  = $wpdb->prepare( "SELECT * FROM $wpdb->posts WHERE post_content LIKE %s", $like );
1773       *
1774       * Example Escape Chain:
1775       *
1776       *     $sql  = esc_sql( $wpdb->esc_like( $input ) );
1777       *
1778       * @since 4.0.0
1779       *
1780       * @param string $text The raw text to be escaped. The input typed by the user
1781       *                     should have no extra or deleted slashes.
1782       * @return string Text in the form of a LIKE phrase. The output is not SQL safe.
1783       *                Call wpdb::prepare() or wpdb::_real_escape() next.
1784       */
1785  	public function esc_like( $text ) {
1786          return addcslashes( $text, '_%\\' );
1787      }
1788  
1789      /**
1790       * Prints SQL/DB error.
1791       *
1792       * @since 0.71
1793       *
1794       * @global array $EZSQL_ERROR Stores error information of query and error string.
1795       *
1796       * @param string $str The error to display.
1797       * @return null|false Null if the showing of errors is enabled, false if disabled.
1798       */
1799  	public function print_error( $str = '' ) {
1800          global $EZSQL_ERROR;
1801  
1802          if ( ! $str ) {
1803              $str = mysqli_error( $this->dbh );
1804          }
1805  
1806          $EZSQL_ERROR[] = array(
1807              'query'     => $this->last_query,
1808              'error_str' => $str,
1809          );
1810  
1811          if ( $this->suppress_errors ) {
1812              return false;
1813          }
1814  
1815          $caller = $this->get_caller();
1816          if ( $caller ) {
1817              // Not translated, as this will only appear in the error log.
1818              $error_str = sprintf( 'WordPress database error %1$s for query %2$s made by %3$s', $str, $this->last_query, $caller );
1819          } else {
1820              $error_str = sprintf( 'WordPress database error %1$s for query %2$s', $str, $this->last_query );
1821          }
1822  
1823          error_log( $error_str );
1824  
1825          // Are we showing errors?
1826          if ( ! $this->show_errors ) {
1827              return false;
1828          }
1829  
1830          wp_load_translations_early();
1831  
1832          // If there is an error then take note of it.
1833          if ( is_multisite() ) {
1834              $msg = sprintf(
1835                  "%s [%s]\n%s\n",
1836                  __( 'WordPress database error:' ),
1837                  $str,
1838                  $this->last_query
1839              );
1840  
1841              if ( defined( 'ERRORLOGFILE' ) ) {
1842                  error_log( $msg, 3, ERRORLOGFILE );
1843              }
1844              if ( defined( 'DIEONDBERROR' ) ) {
1845                  wp_die( $msg );
1846              }
1847          } else {
1848              $str   = htmlspecialchars( $str, ENT_QUOTES );
1849              $query = htmlspecialchars( $this->last_query, ENT_QUOTES );
1850  
1851              printf(
1852                  '<div id="error"><p class="wpdberror"><strong>%s</strong> [%s]<br /><code>%s</code></p></div>',
1853                  __( 'WordPress database error:' ),
1854                  $str,
1855                  $query
1856              );
1857          }
1858  
1859          return null;
1860      }
1861  
1862      /**
1863       * Enables showing of database errors.
1864       *
1865       * This function should be used only to enable showing of errors.
1866       * wpdb::hide_errors() should be used instead for hiding errors.
1867       *
1868       * @since 0.71
1869       *
1870       * @see wpdb::hide_errors()
1871       *
1872       * @param bool $show Optional. Whether to show errors. Default true.
1873       * @return bool Whether showing of errors was previously active.
1874       */
1875  	public function show_errors( $show = true ) {
1876          $errors            = $this->show_errors;
1877          $this->show_errors = $show;
1878          return $errors;
1879      }
1880  
1881      /**
1882       * Disables showing of database errors.
1883       *
1884       * By default database errors are not shown.
1885       *
1886       * @since 0.71
1887       *
1888       * @see wpdb::show_errors()
1889       *
1890       * @return bool Whether showing of errors was previously active.
1891       */
1892  	public function hide_errors() {
1893          $show              = $this->show_errors;
1894          $this->show_errors = false;
1895          return $show;
1896      }
1897  
1898      /**
1899       * Enables or disables suppressing of database errors.
1900       *
1901       * By default database errors are suppressed.
1902       *
1903       * @since 2.5.0
1904       *
1905       * @see wpdb::hide_errors()
1906       *
1907       * @param bool $suppress Optional. Whether to suppress errors. Default true.
1908       * @return bool Whether suppressing of errors was previously active.
1909       */
1910  	public function suppress_errors( $suppress = true ) {
1911          $errors                = $this->suppress_errors;
1912          $this->suppress_errors = (bool) $suppress;
1913          return $errors;
1914      }
1915  
1916      /**
1917       * Kills cached query results.
1918       *
1919       * @since 0.71
1920       */
1921  	public function flush() {
1922          $this->last_result   = array();
1923          $this->col_info      = null;
1924          $this->last_query    = null;
1925          $this->rows_affected = 0;
1926          $this->num_rows      = 0;
1927          $this->last_error    = '';
1928  
1929          if ( $this->result instanceof mysqli_result ) {
1930              mysqli_free_result( $this->result );
1931              $this->result = null;
1932  
1933              // Confidence check before using the handle.
1934              if ( empty( $this->dbh ) || ! ( $this->dbh instanceof mysqli ) ) {
1935                  return;
1936              }
1937  
1938              // Clear out any results from a multi-query.
1939              while ( mysqli_more_results( $this->dbh ) ) {
1940                  mysqli_next_result( $this->dbh );
1941              }
1942          }
1943      }
1944  
1945      /**
1946       * Connects to and selects database.
1947       *
1948       * If `$allow_bail` is false, the lack of database connection will need to be handled manually.
1949       *
1950       * @since 3.0.0
1951       * @since 3.9.0 $allow_bail parameter added.
1952       *
1953       * @param bool $allow_bail Optional. Allows the function to bail. Default true.
1954       * @return bool True with a successful connection, false on failure.
1955       */
1956  	public function db_connect( $allow_bail = true ) {
1957          $this->is_mysql = true;
1958  
1959          $client_flags = defined( 'MYSQL_CLIENT_FLAGS' ) ? MYSQL_CLIENT_FLAGS : 0;
1960  
1961          /*
1962           * Switch error reporting off because WordPress handles its own.
1963           * This is due to the default value change from `MYSQLI_REPORT_OFF`
1964           * to `MYSQLI_REPORT_ERROR|MYSQLI_REPORT_STRICT` in PHP 8.1.
1965           */
1966          mysqli_report( MYSQLI_REPORT_OFF );
1967  
1968          $this->dbh = mysqli_init();
1969  
1970          $host    = $this->dbhost;
1971          $port    = null;
1972          $socket  = null;
1973          $is_ipv6 = false;
1974  
1975          $host_data = $this->parse_db_host( $this->dbhost );
1976          if ( $host_data ) {
1977              list( $host, $port, $socket, $is_ipv6 ) = $host_data;
1978          }
1979  
1980          /*
1981           * If using the `mysqlnd` library, the IPv6 address needs to be enclosed
1982           * in square brackets, whereas it doesn't while using the `libmysqlclient` library.
1983           * @see https://bugs.php.net/bug.php?id=67563
1984           */
1985          if ( $is_ipv6 && extension_loaded( 'mysqlnd' ) ) {
1986              $host = "[$host]";
1987          }
1988  
1989          if ( WP_DEBUG ) {
1990              mysqli_real_connect( $this->dbh, $host, $this->dbuser, $this->dbpassword, null, $port, $socket, $client_flags );
1991          } else {
1992              // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
1993              @mysqli_real_connect( $this->dbh, $host, $this->dbuser, $this->dbpassword, null, $port, $socket, $client_flags );
1994          }
1995  
1996          if ( $this->dbh->connect_errno ) {
1997              $this->dbh = null;
1998          }
1999  
2000          if ( ! $this->dbh && $allow_bail ) {
2001              wp_load_translations_early();
2002  
2003              // Load custom DB error template, if present.
2004              if ( file_exists( WP_CONTENT_DIR . '/db-error.php' ) ) {
2005                  require_once WP_CONTENT_DIR . '/db-error.php';
2006                  die();
2007              }
2008  
2009              $message = '<h1>' . __( 'Error establishing a database connection' ) . "</h1>\n";
2010  
2011              $message .= '<p>' . sprintf(
2012                  /* translators: 1: wp-config.php, 2: Database host. */
2013                  __( 'This either means that the username and password information in your %1$s file is incorrect or that contact with the database server at %2$s could not be established. This could mean your host&#8217;s database server is down.' ),
2014                  '<code>wp-config.php</code>',
2015                  '<code>' . htmlspecialchars( $this->dbhost, ENT_QUOTES ) . '</code>'
2016              ) . "</p>\n";
2017  
2018              $message .= "<ul>\n";
2019              $message .= '<li>' . __( 'Are you sure you have the correct username and password?' ) . "</li>\n";
2020              $message .= '<li>' . __( 'Are you sure you have typed the correct hostname?' ) . "</li>\n";
2021              $message .= '<li>' . __( 'Are you sure the database server is running?' ) . "</li>\n";
2022              $message .= "</ul>\n";
2023  
2024              $message .= '<p>' . sprintf(
2025                  /* translators: %s: Support forums URL. */
2026                  __( 'If you are unsure what these terms mean you should probably contact your host. If you still need help you can always visit the <a href="%s">WordPress support forums</a>.' ),
2027                  __( 'https://wordpress.org/support/forums/' )
2028              ) . "</p>\n";
2029  
2030              $this->bail( $message, 'db_connect_fail' );
2031  
2032              return false;
2033          } elseif ( $this->dbh ) {
2034              if ( ! $this->has_connected ) {
2035                  $this->init_charset();
2036              }
2037  
2038              $this->has_connected = true;
2039  
2040              $this->set_charset( $this->dbh );
2041  
2042              $this->ready = true;
2043              $this->set_sql_mode();
2044              $this->select( $this->dbname, $this->dbh );
2045  
2046              return true;
2047          }
2048  
2049          return false;
2050      }
2051  
2052      /**
2053       * Parses the DB_HOST setting to interpret it for mysqli_real_connect().
2054       *
2055       * mysqli_real_connect() doesn't support the host param including a port or socket
2056       * like mysql_connect() does. This duplicates how mysql_connect() detects a port
2057       * and/or socket file.
2058       *
2059       * @since 4.9.0
2060       *
2061       * @param string $host The DB_HOST setting to parse.
2062       * @return array|false {
2063       *     Array containing the host, the port, the socket and
2064       *     whether it is an IPv6 address, in that order.
2065       *     False if the host couldn't be parsed.
2066       *
2067       *     @type string      $0 Host name.
2068       *     @type string|null $1 Port.
2069       *     @type string|null $2 Socket.
2070       *     @type bool        $3 Whether it is an IPv6 address.
2071       * }
2072       */
2073  	public function parse_db_host( $host ) {
2074          $socket  = null;
2075          $is_ipv6 = false;
2076  
2077          // First peel off the socket parameter from the right, if it exists.
2078          $socket_pos = strpos( $host, ':/' );
2079          if ( false !== $socket_pos ) {
2080              $socket = substr( $host, $socket_pos + 1 );
2081              $host   = substr( $host, 0, $socket_pos );
2082          }
2083  
2084          /*
2085           * We need to check for an IPv6 address first.
2086           * An IPv6 address will always contain at least two colons.
2087           */
2088          if ( substr_count( $host, ':' ) > 1 ) {
2089              $pattern = '#^(?:\[)?(?P<host>[0-9a-fA-F:]+)(?:\]:(?P<port>[\d]+))?#';
2090              $is_ipv6 = true;
2091          } else {
2092              // We seem to be dealing with an IPv4 address.
2093              $pattern = '#^(?P<host>[^:/]*)(?::(?P<port>[\d]+))?#';
2094          }
2095  
2096          $matches = array();
2097          $result  = preg_match( $pattern, $host, $matches );
2098  
2099          if ( 1 !== $result ) {
2100              // Couldn't parse the address, bail.
2101              return false;
2102          }
2103  
2104          $host = ! empty( $matches['host'] ) ? $matches['host'] : '';
2105          // Port cannot be a string; must be null or an integer.
2106          $port = ! empty( $matches['port'] ) ? absint( $matches['port'] ) : null;
2107  
2108          return array( $host, $port, $socket, $is_ipv6 );
2109      }
2110  
2111      /**
2112       * Checks that the connection to the database is still up. If not, try to reconnect.
2113       *
2114       * If this function is unable to reconnect, it will forcibly die, or if called
2115       * after the {@see 'template_redirect'} hook has been fired, return false instead.
2116       *
2117       * If `$allow_bail` is false, the lack of database connection will need to be handled manually.
2118       *
2119       * @since 3.9.0
2120       *
2121       * @param bool $allow_bail Optional. Allows the function to bail. Default true.
2122       * @return bool Whether the connection is up. Exits if down and $allow_bail is true.
2123       */
2124  	public function check_connection( $allow_bail = true ) {
2125          // Check if the connection is alive.
2126          if ( ! empty( $this->dbh ) && mysqli_query( $this->dbh, 'DO 1' ) !== false ) {
2127              return true;
2128          }
2129  
2130          $error_reporting = false;
2131  
2132          // Disable warnings, as we don't want to see a multitude of "unable to connect" messages.
2133          if ( WP_DEBUG ) {
2134              $error_reporting = error_reporting();
2135              error_reporting( $error_reporting & ~E_WARNING );
2136          }
2137  
2138          for ( $tries = 1; $tries <= $this->reconnect_retries; $tries++ ) {
2139              /*
2140               * On the last try, re-enable warnings. We want to see a single instance
2141               * of the "unable to connect" message on the bail() screen, if it appears.
2142               */
2143              if ( $this->reconnect_retries === $tries && WP_DEBUG ) {
2144                  error_reporting( $error_reporting );
2145              }
2146  
2147              if ( $this->db_connect( false ) ) {
2148                  if ( $error_reporting ) {
2149                      error_reporting( $error_reporting );
2150                  }
2151  
2152                  return true;
2153              }
2154  
2155              sleep( 1 );
2156          }
2157  
2158          /*
2159           * If template_redirect has already happened, it's too late for wp_die()/dead_db().
2160           * Let's just return and hope for the best.
2161           */
2162          if ( did_action( 'template_redirect' ) ) {
2163              return false;
2164          }
2165  
2166          if ( ! $allow_bail ) {
2167              return false;
2168          }
2169  
2170          wp_load_translations_early();
2171  
2172          $message = '<h1>' . __( 'Error reconnecting to the database' ) . "</h1>\n";
2173  
2174          $message .= '<p>' . sprintf(
2175              /* translators: %s: Database host. */
2176              __( 'This means that the contact with the database server at %s was lost. This could mean your host&#8217;s database server is down.' ),
2177              '<code>' . htmlspecialchars( $this->dbhost, ENT_QUOTES ) . '</code>'
2178          ) . "</p>\n";
2179  
2180          $message .= "<ul>\n";
2181          $message .= '<li>' . __( 'Are you sure the database server is running?' ) . "</li>\n";
2182          $message .= '<li>' . __( 'Are you sure the database server is not under particularly heavy load?' ) . "</li>\n";
2183          $message .= "</ul>\n";
2184  
2185          $message .= '<p>' . sprintf(
2186              /* translators: %s: Support forums URL. */
2187              __( 'If you are unsure what these terms mean you should probably contact your host. If you still need help you can always visit the <a href="%s">WordPress support forums</a>.' ),
2188              __( 'https://wordpress.org/support/forums/' )
2189          ) . "</p>\n";
2190  
2191          // We weren't able to reconnect, so we better bail.
2192          $this->bail( $message, 'db_connect_fail' );
2193  
2194          /*
2195           * Call dead_db() if bail didn't die, because this database is no more.
2196           * It has ceased to be (at least temporarily).
2197           */
2198          dead_db();
2199      }
2200  
2201      /**
2202       * Performs a database query, using current database connection.
2203       *
2204       * More information can be found on the documentation page.
2205       *
2206       * @since 0.71
2207       *
2208       * @link https://developer.wordpress.org/reference/classes/wpdb/
2209       *
2210       * @param string $query Database query.
2211       * @return int|bool Boolean true for CREATE, ALTER, TRUNCATE and DROP queries. Number of rows
2212       *                  affected/selected for all other queries. Boolean false on error.
2213       */
2214  	public function query( $query ) {
2215          if ( ! $this->ready ) {
2216              $this->check_current_query = true;
2217              return false;
2218          }
2219  
2220          /**
2221           * Filters the database query.
2222           *
2223           * Some queries are made before the plugins have been loaded,
2224           * and thus cannot be filtered with this method.
2225           *
2226           * @since 2.1.0
2227           *
2228           * @param string $query Database query.
2229           */
2230          $query = apply_filters( 'query', $query );
2231  
2232          if ( ! $query ) {
2233              $this->insert_id = 0;
2234              return false;
2235          }
2236  
2237          $this->flush();
2238  
2239          // Log how the function was called.
2240          $this->func_call = "\$db->query(\"$query\")";
2241  
2242          // If we're writing to the database, make sure the query will write safely.
2243          if ( $this->check_current_query && ! $this->check_ascii( $query ) ) {
2244              $stripped_query = $this->strip_invalid_text_from_query( $query );
2245              /*
2246               * strip_invalid_text_from_query() can perform queries, so we need
2247               * to flush again, just to make sure everything is clear.
2248               */
2249              $this->flush();
2250              if ( $stripped_query !== $query ) {
2251                  $this->insert_id  = 0;
2252                  $this->last_query = $query;
2253  
2254                  wp_load_translations_early();
2255  
2256                  $this->last_error = __( 'WordPress database error: Could not perform query because it contains invalid data.' );
2257  
2258                  return false;
2259              }
2260          }
2261  
2262          $this->check_current_query = true;
2263  
2264          // Keep track of the last query for debug.
2265          $this->last_query = $query;
2266  
2267          $this->_do_query( $query );
2268  
2269          // Database server has gone away, try to reconnect.
2270          $mysql_errno = 0;
2271  
2272          if ( $this->dbh instanceof mysqli ) {
2273              $mysql_errno = mysqli_errno( $this->dbh );
2274          } else {
2275              /*
2276               * $dbh is defined, but isn't a real connection.
2277               * Something has gone horribly wrong, let's try a reconnect.
2278               */
2279              $mysql_errno = 2006;
2280          }
2281  
2282          if ( empty( $this->dbh ) || 2006 === $mysql_errno ) {
2283              if ( $this->check_connection() ) {
2284                  $this->_do_query( $query );
2285              } else {
2286                  $this->insert_id = 0;
2287                  return false;
2288              }
2289          }
2290  
2291          // If there is an error then take note of it.
2292          if ( $this->dbh instanceof mysqli ) {
2293              $this->last_error = mysqli_error( $this->dbh );
2294          } else {
2295              $this->last_error = __( 'Unable to retrieve the error message from the database server' );
2296          }
2297  
2298          if ( $this->last_error ) {
2299              // Clear insert_id on a subsequent failed insert.
2300              if ( $this->insert_id && preg_match( '/^\s*(insert|replace)\s/i', $query ) ) {
2301                  $this->insert_id = 0;
2302              }
2303  
2304              $this->print_error();
2305              return false;
2306          }
2307  
2308          if ( preg_match( '/^\s*(create|alter|truncate|drop)\s/i', $query ) ) {
2309              $return_val = $this->result;
2310          } elseif ( preg_match( '/^\s*(insert|delete|update|replace)\s/i', $query ) ) {
2311              $this->rows_affected = mysqli_affected_rows( $this->dbh );
2312  
2313              // Take note of the insert_id.
2314              if ( preg_match( '/^\s*(insert|replace)\s/i', $query ) ) {
2315                  $this->insert_id = mysqli_insert_id( $this->dbh );
2316              }
2317  
2318              // Return number of rows affected.
2319              $return_val = $this->rows_affected;
2320          } else {
2321              $num_rows = 0;
2322  
2323              if ( $this->result instanceof mysqli_result ) {
2324                  while ( $row = mysqli_fetch_object( $this->result ) ) {
2325                      $this->last_result[ $num_rows ] = $row;
2326                      ++$num_rows;
2327                  }
2328              }
2329  
2330              // Log and return the number of rows selected.
2331              $this->num_rows = $num_rows;
2332              $return_val     = $num_rows;
2333          }
2334  
2335          return $return_val;
2336      }
2337  
2338      /**
2339       * Internal function to perform the mysqli_query() call.
2340       *
2341       * @since 3.9.0
2342       *
2343       * @see wpdb::query()
2344       *
2345       * @param string $query The query to run.
2346       */
2347  	private function _do_query( $query ) {
2348          if ( defined( 'SAVEQUERIES' ) && SAVEQUERIES ) {
2349              $this->timer_start();
2350          }
2351  
2352          if ( ! empty( $this->dbh ) ) {
2353              $this->result = mysqli_query( $this->dbh, $query );
2354          }
2355  
2356          ++$this->num_queries;
2357  
2358          if ( defined( 'SAVEQUERIES' ) && SAVEQUERIES ) {
2359              $this->log_query(
2360                  $query,
2361                  $this->timer_stop(),
2362                  $this->get_caller(),
2363                  $this->time_start,
2364                  array()
2365              );
2366          }
2367      }
2368  
2369      /**
2370       * Logs query data.
2371       *
2372       * @since 5.3.0
2373       *
2374       * @param string $query           The query's SQL.
2375       * @param float  $query_time      Total time spent on the query, in seconds.
2376       * @param string $query_callstack Comma-separated list of the calling functions.
2377       * @param float  $query_start     Unix timestamp of the time at the start of the query.
2378       * @param array  $query_data      Custom query data.
2379       */
2380  	public function log_query( $query, $query_time, $query_callstack, $query_start, $query_data ) {
2381          /**
2382           * Filters the custom data to log alongside a query.
2383           *
2384           * Caution should be used when modifying any of this data, it is recommended that any additional
2385           * information you need to store about a query be added as a new associative array element.
2386           *
2387           * @since 5.3.0
2388           *
2389           * @param array  $query_data      Custom query data.
2390           * @param string $query           The query's SQL.
2391           * @param float  $query_time      Total time spent on the query, in seconds.
2392           * @param string $query_callstack Comma-separated list of the calling functions.
2393           * @param float  $query_start     Unix timestamp of the time at the start of the query.
2394           */
2395          $query_data = apply_filters( 'log_query_custom_data', $query_data, $query, $query_time, $query_callstack, $query_start );
2396  
2397          $this->queries[] = array(
2398              $query,
2399              $query_time,
2400              $query_callstack,
2401              $query_start,
2402              $query_data,
2403          );
2404      }
2405  
2406      /**
2407       * Generates and returns a placeholder escape string for use in queries returned by ::prepare().
2408       *
2409       * @since 4.8.3
2410       *
2411       * @return string String to escape placeholders.
2412       */
2413  	public function placeholder_escape() {
2414          static $placeholder;
2415  
2416          if ( ! $placeholder ) {
2417              // Old WP installs may not have AUTH_SALT defined.
2418              $salt = defined( 'AUTH_SALT' ) && AUTH_SALT ? AUTH_SALT : (string) rand();
2419  
2420              $placeholder = '{' . hash_hmac( 'sha256', uniqid( $salt, true ), $salt ) . '}';
2421          }
2422  
2423          /*
2424           * Add the filter to remove the placeholder escaper. Uses priority 0, so that anything
2425           * else attached to this filter will receive the query with the placeholder string removed.
2426           */
2427          if ( false === has_filter( 'query', array( $this, 'remove_placeholder_escape' ) ) ) {
2428              add_filter( 'query', array( $this, 'remove_placeholder_escape' ), 0 );
2429          }
2430  
2431          return $placeholder;
2432      }
2433  
2434      /**
2435       * Adds a placeholder escape string, to escape anything that resembles a printf() placeholder.
2436       *
2437       * @since 4.8.3
2438       *
2439       * @param string $query The query to escape.
2440       * @return string The query with the placeholder escape string inserted where necessary.
2441       */
2442  	public function add_placeholder_escape( $query ) {
2443          /*
2444           * To prevent returning anything that even vaguely resembles a placeholder,
2445           * we clobber every % we can find.
2446           */
2447          return str_replace( '%', $this->placeholder_escape(), $query );
2448      }
2449  
2450      /**
2451       * Removes the placeholder escape strings from a query.
2452       *
2453       * @since 4.8.3
2454       *
2455       * @param string $query The query from which the placeholder will be removed.
2456       * @return string The query with the placeholder removed.
2457       */
2458  	public function remove_placeholder_escape( $query ) {
2459          return str_replace( $this->placeholder_escape(), '%', $query );
2460      }
2461  
2462      /**
2463       * Inserts a row into the table.
2464       *
2465       * Examples:
2466       *
2467       *     $wpdb->insert(
2468       *         'table',
2469       *         array(
2470       *             'column1' => 'foo',
2471       *             'column2' => 'bar',
2472       *         )
2473       *     );
2474       *     $wpdb->insert(
2475       *         'table',
2476       *         array(
2477       *             'column1' => 'foo',
2478       *             'column2' => 1337,
2479       *         ),
2480       *         array(
2481       *             '%s',
2482       *             '%d',
2483       *         )
2484       *     );
2485       *
2486       * @since 2.5.0
2487       *
2488       * @see wpdb::prepare()
2489       * @see wpdb::$field_types
2490       * @see wp_set_wpdb_vars()
2491       *
2492       * @param string          $table  Table name.
2493       * @param array           $data   Data to insert (in column => value pairs).
2494       *                                Both `$data` columns and `$data` values should be "raw" (neither should be SQL escaped).
2495       *                                Sending a null value will cause the column to be set to NULL - the corresponding
2496       *                                format is ignored in this case.
2497       * @param string[]|string $format Optional. An array of formats to be mapped to each of the value in `$data`.
2498       *                                If string, that format will be used for all of the values in `$data`.
2499       *                                A format is one of '%d', '%f', '%s' (integer, float, string).
2500       *                                If omitted, all values in `$data` will be treated as strings unless otherwise
2501       *                                specified in wpdb::$field_types. Default null.
2502       * @return int|false The number of rows inserted, or false on error.
2503       */
2504  	public function insert( $table, $data, $format = null ) {
2505          return $this->_insert_replace_helper( $table, $data, $format, 'INSERT' );
2506      }
2507  
2508      /**
2509       * Replaces a row in the table or inserts it if it does not exist, based on a PRIMARY KEY or a UNIQUE index.
2510       *
2511       * A REPLACE works exactly like an INSERT, except that if an old row in the table has the same value as a new row
2512       * for a PRIMARY KEY or a UNIQUE index, the old row is deleted before the new row is inserted.
2513       *
2514       * Examples:
2515       *
2516       *     $wpdb->replace(
2517       *         'table',
2518       *         array(
2519       *             'ID'      => 123,
2520       *             'column1' => 'foo',
2521       *             'column2' => 'bar',
2522       *         )
2523       *     );
2524       *     $wpdb->replace(
2525       *         'table',
2526       *         array(
2527       *             'ID'      => 456,
2528       *             'column1' => 'foo',
2529       *             'column2' => 1337,
2530       *         ),
2531       *         array(
2532       *             '%d',
2533       *             '%s',
2534       *             '%d',
2535       *         )
2536       *     );
2537       *
2538       * @since 3.0.0
2539       *
2540       * @see wpdb::prepare()
2541       * @see wpdb::$field_types
2542       * @see wp_set_wpdb_vars()
2543       *
2544       * @param string          $table  Table name.
2545       * @param array           $data   Data to insert (in column => value pairs).
2546       *                                Both `$data` columns and `$data` values should be "raw" (neither should be SQL escaped).
2547       *                                A primary key or unique index is required to perform a replace operation.
2548       *                                Sending a null value will cause the column to be set to NULL - the corresponding
2549       *                                format is ignored in this case.
2550       * @param string[]|string $format Optional. An array of formats to be mapped to each of the value in `$data`.
2551       *                                If string, that format will be used for all of the values in `$data`.
2552       *                                A format is one of '%d', '%f', '%s' (integer, float, string).
2553       *                                If omitted, all values in `$data` will be treated as strings unless otherwise
2554       *                                specified in wpdb::$field_types. Default null.
2555       * @return int|false The number of rows affected, or false on error.
2556       */
2557  	public function replace( $table, $data, $format = null ) {
2558          return $this->_insert_replace_helper( $table, $data, $format, 'REPLACE' );
2559      }
2560  
2561      /**
2562       * Helper function for insert and replace.
2563       *
2564       * Runs an insert or replace query based on `$type` argument.
2565       *
2566       * @since 3.0.0
2567       *
2568       * @see wpdb::prepare()
2569       * @see wpdb::$field_types
2570       * @see wp_set_wpdb_vars()
2571       *
2572       * @param string          $table  Table name.
2573       * @param array           $data   Data to insert (in column => value pairs).
2574       *                                Both `$data` columns and `$data` values should be "raw" (neither should be SQL escaped).
2575       *                                Sending a null value will cause the column to be set to NULL - the corresponding
2576       *                                format is ignored in this case.
2577       * @param string[]|string $format Optional. An array of formats to be mapped to each of the value in `$data`.
2578       *                                If string, that format will be used for all of the values in `$data`.
2579       *                                A format is one of '%d', '%f', '%s' (integer, float, string).
2580       *                                If omitted, all values in `$data` will be treated as strings unless otherwise
2581       *                                specified in wpdb::$field_types. Default null.
2582       * @param string          $type   Optional. Type of operation. Either 'INSERT' or 'REPLACE'.
2583       *                                Default 'INSERT'.
2584       * @return int|false The number of rows affected, or false on error.
2585       */
2586  	public function _insert_replace_helper( $table, $data, $format = null, $type = 'INSERT' ) {
2587          $this->insert_id = 0;
2588  
2589          if ( ! in_array( strtoupper( $type ), array( 'REPLACE', 'INSERT' ), true ) ) {
2590              return false;
2591          }
2592  
2593          $data = $this->process_fields( $table, $data, $format );
2594          if ( false === $data ) {
2595              return false;
2596          }
2597  
2598          $formats = array();
2599          $values  = array();
2600          foreach ( $data as $value ) {
2601              if ( is_null( $value['value'] ) ) {
2602                  $formats[] = 'NULL';
2603                  continue;
2604              }
2605  
2606              $formats[] = $value['format'];
2607              $values[]  = $value['value'];
2608          }
2609  
2610          $fields  = '`' . implode( '`, `', array_keys( $data ) ) . '`';
2611          $formats = implode( ', ', $formats );
2612  
2613          $sql = "$type INTO `$table` ($fields) VALUES ($formats)";
2614  
2615          $this->check_current_query = false;
2616          return $this->query( $this->prepare( $sql, $values ) );
2617      }
2618  
2619      /**
2620       * Updates a row in the table.
2621       *
2622       * Examples:
2623       *
2624       *     $wpdb->update(
2625       *         'table',
2626       *         array(
2627       *             'column1' => 'foo',
2628       *             'column2' => 'bar',
2629       *         ),
2630       *         array(
2631       *             'ID' => 1,
2632       *         )
2633       *     );
2634       *     $wpdb->update(
2635       *         'table',
2636       *         array(
2637       *             'column1' => 'foo',
2638       *             'column2' => 1337,
2639       *         ),
2640       *         array(
2641       *             'ID' => 1,
2642       *         ),
2643       *         array(
2644       *             '%s',
2645       *             '%d',
2646       *         ),
2647       *         array(
2648       *             '%d',
2649       *         )
2650       *     );
2651       *
2652       * @since 2.5.0
2653       *
2654       * @see wpdb::prepare()
2655       * @see wpdb::$field_types
2656       * @see wp_set_wpdb_vars()
2657       *
2658       * @param string          $table        Table name.
2659       * @param array           $data         Data to update (in column => value pairs).
2660       *                                      Both $data columns and $data values should be "raw" (neither should be SQL escaped).
2661       *                                      Sending a null value will cause the column to be set to NULL - the corresponding
2662       *                                      format is ignored in this case.
2663       * @param array           $where        A named array of WHERE clauses (in column => value pairs).
2664       *                                      Multiple clauses will be joined with ANDs.
2665       *                                      Both $where columns and $where values should be "raw".
2666       *                                      Sending a null value will create an IS NULL comparison - the corresponding
2667       *                                      format will be ignored in this case.
2668       * @param string[]|string $format       Optional. An array of formats to be mapped to each of the values in $data.
2669       *                                      If string, that format will be used for all of the values in $data.
2670       *                                      A format is one of '%d', '%f', '%s' (integer, float, string).
2671       *                                      If omitted, all values in $data will be treated as strings unless otherwise
2672       *                                      specified in wpdb::$field_types. Default null.
2673       * @param string[]|string $where_format Optional. An array of formats to be mapped to each of the values in $where.
2674       *                                      If string, that format will be used for all of the items in $where.
2675       *                                      A format is one of '%d', '%f', '%s' (integer, float, string).
2676       *                                      If omitted, all values in $where will be treated as strings unless otherwise
2677       *                                      specified in wpdb::$field_types. Default null.
2678       * @return int|false The number of rows updated, or false on error.
2679       */
2680  	public function update( $table, $data, $where, $format = null, $where_format = null ) {
2681          if ( ! is_array( $data ) || ! is_array( $where ) ) {
2682              return false;
2683          }
2684  
2685          $data = $this->process_fields( $table, $data, $format );
2686          if ( false === $data ) {
2687              return false;
2688          }
2689          $where = $this->process_fields( $table, $where, $where_format );
2690          if ( false === $where ) {
2691              return false;
2692          }
2693  
2694          $fields     = array();
2695          $conditions = array();
2696          $values     = array();
2697          foreach ( $data as $field => $value ) {
2698              if ( is_null( $value['value'] ) ) {
2699                  $fields[] = "`$field` = NULL";
2700                  continue;
2701              }
2702  
2703              $fields[] = "`$field` = " . $value['format'];
2704              $values[] = $value['value'];
2705          }
2706          foreach ( $where as $field => $value ) {
2707              if ( is_null( $value['value'] ) ) {
2708                  $conditions[] = "`$field` IS NULL";
2709                  continue;
2710              }
2711  
2712              $conditions[] = "`$field` = " . $value['format'];
2713              $values[]     = $value['value'];
2714          }
2715  
2716          $fields     = implode( ', ', $fields );
2717          $conditions = implode( ' AND ', $conditions );
2718  
2719          $sql = "UPDATE `$table` SET $fields WHERE $conditions";
2720  
2721          $this->check_current_query = false;
2722          return $this->query( $this->prepare( $sql, $values ) );
2723      }
2724  
2725      /**
2726       * Deletes a row in the table.
2727       *
2728       * Examples:
2729       *
2730       *     $wpdb->delete(
2731       *         'table',
2732       *         array(
2733       *             'ID' => 1,
2734       *         )
2735       *     );
2736       *     $wpdb->delete(
2737       *         'table',
2738       *         array(
2739       *             'ID' => 1,
2740       *         ),
2741       *         array(
2742       *             '%d',
2743       *         )
2744       *     );
2745       *
2746       * @since 3.4.0
2747       *
2748       * @see wpdb::prepare()
2749       * @see wpdb::$field_types
2750       * @see wp_set_wpdb_vars()
2751       *
2752       * @param string          $table        Table name.
2753       * @param array           $where        A named array of WHERE clauses (in column => value pairs).
2754       *                                      Multiple clauses will be joined with ANDs.
2755       *                                      Both $where columns and $where values should be "raw".
2756       *                                      Sending a null value will create an IS NULL comparison - the corresponding
2757       *                                      format will be ignored in this case.
2758       * @param string[]|string $where_format Optional. An array of formats to be mapped to each of the values in $where.
2759       *                                      If string, that format will be used for all of the items in $where.
2760       *                                      A format is one of '%d', '%f', '%s' (integer, float, string).
2761       *                                      If omitted, all values in $where will be treated as strings unless otherwise
2762       *                                      specified in wpdb::$field_types. Default null.
2763       * @return int|false The number of rows deleted, or false on error.
2764       */
2765  	public function delete( $table, $where, $where_format = null ) {
2766          if ( ! is_array( $where ) ) {
2767              return false;
2768          }
2769  
2770          $where = $this->process_fields( $table, $where, $where_format );
2771          if ( false === $where ) {
2772              return false;
2773          }
2774  
2775          $conditions = array();
2776          $values     = array();
2777          foreach ( $where as $field => $value ) {
2778              if ( is_null( $value['value'] ) ) {
2779                  $conditions[] = "`$field` IS NULL";
2780                  continue;
2781              }
2782  
2783              $conditions[] = "`$field` = " . $value['format'];
2784              $values[]     = $value['value'];
2785          }
2786  
2787          $conditions = implode( ' AND ', $conditions );
2788  
2789          $sql = "DELETE FROM `$table` WHERE $conditions";
2790  
2791          $this->check_current_query = false;
2792          return $this->query( $this->prepare( $sql, $values ) );
2793      }
2794  
2795      /**
2796       * Processes arrays of field/value pairs and field formats.
2797       *
2798       * This is a helper method for wpdb's CRUD methods, which take field/value pairs
2799       * for inserts, updates, and where clauses. This method first pairs each value
2800       * with a format. Then it determines the charset of that field, using that
2801       * to determine if any invalid text would be stripped. If text is stripped,
2802       * then field processing is rejected and the query fails.
2803       *
2804       * @since 4.2.0
2805       *
2806       * @param string          $table  Table name.
2807       * @param array           $data   Array of values keyed by their field names.
2808       * @param string[]|string $format Formats or format to be mapped to the values in the data.
2809       * @return array|false An array of fields that contain paired value and formats.
2810       *                     False for invalid values.
2811       */
2812  	protected function process_fields( $table, $data, $format ) {
2813          $data = $this->process_field_formats( $data, $format );
2814          if ( false === $data ) {
2815              return false;
2816          }
2817  
2818          $data = $this->process_field_charsets( $data, $table );
2819          if ( false === $data ) {
2820              return false;
2821          }
2822  
2823          $data = $this->process_field_lengths( $data, $table );
2824          if ( false === $data ) {
2825              return false;
2826          }
2827  
2828          $converted_data = $this->strip_invalid_text( $data );
2829  
2830          if ( $data !== $converted_data ) {
2831  
2832              $problem_fields = array();
2833              foreach ( $data as $field => $value ) {
2834                  if ( $value !== $converted_data[ $field ] ) {
2835                      $problem_fields[] = $field;
2836                  }
2837              }
2838  
2839              wp_load_translations_early();
2840  
2841              if ( 1 === count( $problem_fields ) ) {
2842                  $this->last_error = sprintf(
2843                      /* translators: %s: Database field where the error occurred. */
2844                      __( 'WordPress database error: Processing the value for the following field failed: %s. The supplied value may be too long or contains invalid data.' ),
2845                      reset( $problem_fields )
2846                  );
2847              } else {
2848                  $this->last_error = sprintf(
2849                      /* translators: %s: Database fields where the error occurred. */
2850                      __( 'WordPress database error: Processing the values for the following fields failed: %s. The supplied values may be too long or contain invalid data.' ),
2851                      implode( ', ', $problem_fields )
2852                  );
2853              }
2854  
2855              return false;
2856          }
2857  
2858          return $data;
2859      }
2860  
2861      /**
2862       * Prepares arrays of value/format pairs as passed to wpdb CRUD methods.
2863       *
2864       * @since 4.2.0
2865       *
2866       * @param array           $data   Array of values keyed by their field names.
2867       * @param string[]|string $format Formats or format to be mapped to the values in the data.
2868       * @return array {
2869       *     Array of values and formats keyed by their field names.
2870       *
2871       *     @type array ...$0 {
2872       *         Value and format for this field.
2873       *
2874       *         @type mixed  $value  The value to be formatted.
2875       *         @type string $format The format to be mapped to the value.
2876       *     }
2877       * }
2878       */
2879  	protected function process_field_formats( $data, $format ) {
2880          $formats          = (array) $format;
2881          $original_formats = $formats;
2882  
2883          foreach ( $data as $field => $value ) {
2884              $value = array(
2885                  'value'  => $value,
2886                  'format' => '%s',
2887              );
2888  
2889              if ( ! empty( $format ) ) {
2890                  $value['format'] = array_shift( $formats );
2891                  if ( ! $value['format'] ) {
2892                      $value['format'] = reset( $original_formats );
2893                  }
2894              } elseif ( isset( $this->field_types[ $field ] ) ) {
2895                  $value['format'] = $this->field_types[ $field ];
2896              }
2897  
2898              $data[ $field ] = $value;
2899          }
2900  
2901          return $data;
2902      }
2903  
2904      /**
2905       * Adds field charsets to field/value/format arrays generated by wpdb::process_field_formats().
2906       *
2907       * @since 4.2.0
2908       *
2909       * @param array  $data {
2910       *     Array of values and formats keyed by their field names,
2911       *     as it comes from the wpdb::process_field_formats() method.
2912       *
2913       *     @type array ...$0 {
2914       *         Value and format for this field.
2915       *
2916       *         @type mixed  $value  The value to be formatted.
2917       *         @type string $format The format to be mapped to the value.
2918       *     }
2919       * }
2920       * @param string $table Table name.
2921       * @return array|false {
2922       *     The same array of data with additional 'charset' keys, or false if
2923       *     the charset for the table cannot be found.
2924       *
2925       *     @type array ...$0 {
2926       *         Value, format, and charset for this field.
2927       *
2928       *         @type mixed        $value   The value to be formatted.
2929       *         @type string       $format  The format to be mapped to the value.
2930       *         @type string|false $charset The charset to be used for the value.
2931       *     }
2932       * }
2933       */
2934  	protected function process_field_charsets( $data, $table ) {
2935          foreach ( $data as $field => $value ) {
2936              if ( '%d' === $value['format'] || '%f' === $value['format'] ) {
2937                  /*
2938                   * We can skip this field if we know it isn't a string.
2939                   * This checks %d/%f versus ! %s because its sprintf() could take more.
2940                   */
2941                  $value['charset'] = false;
2942              } else {
2943                  $value['charset'] = $this->get_col_charset( $table, $field );
2944                  if ( is_wp_error( $value['charset'] ) ) {
2945                      return false;
2946                  }
2947              }
2948  
2949              $data[ $field ] = $value;
2950          }
2951  
2952          return $data;
2953      }
2954  
2955      /**
2956       * For string fields, records the maximum string length that field can safely save.
2957       *
2958       * @since 4.2.1
2959       *
2960       * @param array  $data {
2961       *     Array of values, formats, and charsets keyed by their field names,
2962       *     as it comes from the wpdb::process_field_charsets() method.
2963       *
2964       *     @type array ...$0 {
2965       *         Value, format, and charset for this field.
2966       *
2967       *         @type mixed        $value   The value to be formatted.
2968       *         @type string       $format  The format to be mapped to the value.
2969       *         @type string|false $charset The charset to be used for the value.
2970       *     }
2971       * }
2972       * @param string $table Table name.
2973       * @return array|false {
2974       *     The same array of data with additional 'length' keys, or false if
2975       *     information for the table cannot be found.
2976       *
2977       *     @type array ...$0 {
2978       *         Value, format, charset, and length for this field.
2979       *
2980       *         @type mixed        $value   The value to be formatted.
2981       *         @type string       $format  The format to be mapped to the value.
2982       *         @type string|false $charset The charset to be used for the value.
2983       *         @type array|false  $length  {
2984       *             Information about the maximum length of the value.
2985       *             False if the column has no length.
2986       *
2987       *             @type string $type   One of 'byte' or 'char'.
2988       *             @type int    $length The column length.
2989       *         }
2990       *     }
2991       * }
2992       */
2993  	protected function process_field_lengths( $data, $table ) {
2994          foreach ( $data as $field => $value ) {
2995              if ( '%d' === $value['format'] || '%f' === $value['format'] ) {
2996                  /*
2997                   * We can skip this field if we know it isn't a string.
2998                   * This checks %d/%f versus ! %s because its sprintf() could take more.
2999                   */
3000                  $value['length'] = false;
3001              } else {
3002                  $value['length'] = $this->get_col_length( $table, $field );
3003                  if ( is_wp_error( $value['length'] ) ) {
3004                      return false;
3005                  }
3006              }
3007  
3008              $data[ $field ] = $value;
3009          }
3010  
3011          return $data;
3012      }
3013  
3014      /**
3015       * Retrieves one value from the database.
3016       *
3017       * Executes a SQL query and returns the value from the SQL result.
3018       * If the SQL result contains more than one column and/or more than one row,
3019       * the value in the column and row specified is returned. If $query is null,
3020       * the value in the specified column and row from the previous SQL result is returned.
3021       *
3022       * Returns null both on failure and when the matched cell value is an empty
3023       * string. To distinguish the two cases, check {@see self::$last_error}.
3024       *
3025       * @since 0.71
3026       *
3027       * @param string|null $query Optional. SQL query. Defaults to null, use the result from the previous query.
3028       * @param int         $x     Optional. Column of value to return. Indexed from 0. Default 0.
3029       * @param int         $y     Optional. Row of value to return. Indexed from 0. Default 0.
3030       * @return string|null Database query result (as string), or null on failure or when the value is an empty string.
3031       * @phpstan-return non-empty-string|null
3032       */
3033  	public function get_var( $query = null, $x = 0, $y = 0 ) {
3034          $this->func_call = "\$db->get_var(\"$query\", $x, $y)";
3035  
3036          if ( $query ) {
3037              if ( $this->check_current_query && $this->check_safe_collation( $query ) ) {
3038                  $this->check_current_query = false;
3039              }
3040  
3041              $this->query( $query );
3042          }
3043  
3044          // Extract var out of cached results based on x,y vals.
3045          if ( ! empty( $this->last_result[ $y ] ) ) {
3046              /**
3047               * Column values.
3048               *
3049               * These are returned from the database as strings, or null for SQL NULL, but get_object_vars() types the
3050               * property values as mixed.
3051               *
3052               * @var list<string|null> $values
3053               */
3054              $values = array_values( get_object_vars( $this->last_result[ $y ] ) );
3055          }
3056  
3057          // If there is a value return it, else return null.
3058          return ( isset( $values[ $x ] ) && '' !== $values[ $x ] ) ? $values[ $x ] : null;
3059      }
3060  
3061      /**
3062       * Retrieves one row from the database.
3063       *
3064       * Executes a SQL query and returns the row from the SQL result.
3065       *
3066       * @since 0.71
3067       *
3068       * @param string|null $query  SQL query.
3069       * @param string      $output Optional. The required return type. One of OBJECT, ARRAY_A, or ARRAY_N, which
3070       *                            correspond to an stdClass object, an associative array, or a numeric array,
3071       *                            respectively. Default OBJECT.
3072       * @param int         $y      Optional. Row to return. Indexed from 0. Default 0.
3073       * @return array|object|null Database query result in format specified by $output or null on failure.
3074       * @phpstan-param 'OBJECT'|'ARRAY_A'|'ARRAY_N' $output
3075       * @phpstan-return (
3076       *     $query is non-falsy-string
3077       *         ? (
3078       *             $output is 'OBJECT'
3079       *                 ? stdClass|null
3080       *                 : (
3081       *                     $output is 'ARRAY_A'
3082       *                         ? array<array-key, mixed>|null
3083       *                         : (
3084       *                             $output is 'ARRAY_N'
3085       *                                 ? list<mixed>|null
3086       *                                 : null
3087       *                         )
3088       *                 )
3089       *         )
3090       *         : null
3091       * )
3092       */
3093  	public function get_row( $query = null, $output = OBJECT, $y = 0 ) {
3094          $this->func_call = "\$db->get_row(\"$query\",$output,$y)";
3095  
3096          if ( $query ) {
3097              if ( $this->check_current_query && $this->check_safe_collation( $query ) ) {
3098                  $this->check_current_query = false;
3099              }
3100  
3101              $this->query( $query );
3102          } else {
3103              return null;
3104          }
3105  
3106          if ( ! isset( $this->last_result[ $y ] ) ) {
3107              return null;
3108          }
3109  
3110          if ( OBJECT === $output ) {
3111              return $this->last_result[ $y ] ? $this->last_result[ $y ] : null;
3112          } elseif ( ARRAY_A === $output ) {
3113              return $this->last_result[ $y ] ? get_object_vars( $this->last_result[ $y ] ) : null;
3114          } elseif ( ARRAY_N === $output ) {
3115              return $this->last_result[ $y ] ? array_values( get_object_vars( $this->last_result[ $y ] ) ) : null;
3116          } elseif ( OBJECT === strtoupper( $output ) ) {
3117              // Back compat for OBJECT being previously case-insensitive.
3118              return $this->last_result[ $y ] ? $this->last_result[ $y ] : null;
3119          } else {
3120              $this->print_error( ' $db->get_row(string query, output type, int offset) -- Output type must be one of: OBJECT, ARRAY_A, ARRAY_N' );
3121          }
3122          return null;
3123      }
3124  
3125      /**
3126       * Retrieves one column from the database.
3127       *
3128       * Executes a SQL query and returns the column from the SQL result.
3129       * If the SQL result contains more than one column, the column specified is returned.
3130       * If $query is null, the specified column from the previous SQL result is returned.
3131       *
3132       * @since 0.71
3133       *
3134       * @param string|null $query Optional. SQL query. Defaults to previous query.
3135       * @param int         $x     Optional. Column to return. Indexed from 0. Default 0.
3136       * @return array Database query result. Array indexed from 0 by SQL result row number.
3137       * @phpstan-return list<non-empty-string|null>
3138       */
3139  	public function get_col( $query = null, $x = 0 ) {
3140          if ( $query ) {
3141              if ( $this->check_current_query && $this->check_safe_collation( $query ) ) {
3142                  $this->check_current_query = false;
3143              }
3144  
3145              $this->query( $query );
3146          }
3147  
3148          $new_array = array();
3149          // Extract the column values.
3150          if ( $this->last_result ) {
3151              for ( $i = 0, $j = count( $this->last_result ); $i < $j; $i++ ) {
3152                  $new_array[] = $this->get_var( null, $x, $i );
3153              }
3154          }
3155          return $new_array;
3156      }
3157  
3158      /**
3159       * Retrieves an entire SQL result set from the database (i.e., many rows).
3160       *
3161       * Executes a SQL query and returns the entire SQL result.
3162       *
3163       * Returns an empty array when no rows match or when the database
3164       * reports an error for the query. Returns null when $query is empty,
3165       * when $output is not one of the recognized constants, or when the
3166       * query cannot run because the connection is not ready.
3167       *
3168       * @since 0.71
3169       *
3170       * @param string|null $query  SQL query.
3171       * @param string      $output Optional. Any of ARRAY_A | ARRAY_N | OBJECT | OBJECT_K constants.
3172       *                            With one of the first three, return an array of rows indexed
3173       *                            from 0 by SQL result row number. Each row is an associative array
3174       *                            (column => value, ...), a numerically indexed array (0 => value, ...),
3175       *                            or an object ( ->column = value ), respectively. With OBJECT_K,
3176       *                            return an associative array of row objects keyed by the value
3177       *                            of each row's first column's value. Duplicate keys are discarded.
3178       *                            Default OBJECT.
3179       * @return array|null Database query results. Empty array when no rows match
3180       *                    or on database error. Null when $query is empty, when
3181       *                    $output is invalid, or when the connection is not ready.
3182       * @phpstan-param 'OBJECT'|'OBJECT_K'|'ARRAY_A'|'ARRAY_N' $output
3183       * @phpstan-return (
3184       *     $query is non-falsy-string
3185       *         ? (
3186       *             $output is 'OBJECT'
3187       *                 ? list<stdClass>|null
3188       *                 : (
3189       *                     $output is 'OBJECT_K'
3190       *                         ? array<array-key, stdClass>
3191       *                         : (
3192       *                             $output is 'ARRAY_A'
3193       *                                 ? list<array<array-key, mixed>>
3194       *                                 : (
3195       *                                     $output is 'ARRAY_N'
3196       *                                         ? list<list<mixed>>
3197       *                                         : null
3198       *                                 )
3199       *                         )
3200       *                 )
3201       *         )
3202       *         : null
3203       * )
3204       */
3205  	public function get_results( $query = null, $output = OBJECT ) {
3206          $this->func_call = "\$db->get_results(\"$query\", $output)";
3207  
3208          if ( $query ) {
3209              if ( $this->check_current_query && $this->check_safe_collation( $query ) ) {
3210                  $this->check_current_query = false;
3211              }
3212  
3213              $this->query( $query );
3214          } else {
3215              return null;
3216          }
3217  
3218          $new_array = array();
3219          if ( OBJECT === $output ) {
3220              // Return an integer-keyed array of row objects.
3221              return $this->last_result;
3222          } elseif ( OBJECT_K === $output ) {
3223              /*
3224               * Return an array of row objects with keys from column 1.
3225               * (Duplicates are discarded.)
3226               */
3227              if ( $this->last_result ) {
3228                  foreach ( $this->last_result as $row ) {
3229                      $var_by_ref = get_object_vars( $row );
3230                      /**
3231                       * The first column's value is used as the key.
3232                       *
3233                       * A SQL NULL value surfaces as null here, so coerce it to an empty string to avoid the deprecated
3234                       * use of null as an array offset (PHP 8.5+).
3235                       *
3236                       * @var array-key $key
3237                       */
3238                      $key = array_shift( $var_by_ref ) ?? '';
3239                      if ( ! isset( $new_array[ $key ] ) ) {
3240                          $new_array[ $key ] = $row;
3241                      }
3242                  }
3243              }
3244              return $new_array;
3245          } elseif ( ARRAY_A === $output || ARRAY_N === $output ) {
3246              // Return an integer-keyed array of...
3247              if ( $this->last_result ) {
3248                  if ( ARRAY_N === $output ) {
3249                      foreach ( (array) $this->last_result as $row ) {
3250                          // ...integer-keyed row arrays.
3251                          $new_array[] = array_values( get_object_vars( $row ) );
3252                      }
3253                  } else {
3254                      foreach ( (array) $this->last_result as $row ) {
3255                          // ...column name-keyed row arrays.
3256                          $new_array[] = get_object_vars( $row );
3257                      }
3258                  }
3259              }
3260              return $new_array;
3261          } elseif ( strtoupper( $output ) === OBJECT ) {
3262              // Back compat for OBJECT being previously case-insensitive.
3263              return $this->last_result;
3264          }
3265          return null;
3266      }
3267  
3268      /**
3269       * Retrieves the character set for the given table.
3270       *
3271       * @since 4.2.0
3272       *
3273       * @param string $table Table name.
3274       * @return string|WP_Error Table character set, WP_Error object if it couldn't be found.
3275       */
3276  	protected function get_table_charset( $table ) {
3277          $tablekey = strtolower( $table );
3278  
3279          /**
3280           * Filters the table charset value before the DB is checked.
3281           *
3282           * Returning a non-null value from the filter will effectively short-circuit
3283           * checking the DB for the charset, returning that value instead.
3284           *
3285           * @since 4.2.0
3286           *
3287           * @param string|WP_Error|null $charset The character set to use, WP_Error object
3288           *                                      if it couldn't be found. Default null.
3289           * @param string               $table   The name of the table being checked.
3290           */
3291          $charset = apply_filters( 'pre_get_table_charset', null, $table );
3292          if ( null !== $charset ) {
3293              return $charset;
3294          }
3295  
3296          if ( isset( $this->table_charset[ $tablekey ] ) ) {
3297              return $this->table_charset[ $tablekey ];
3298          }
3299  
3300          $charsets = array();
3301          $columns  = array();
3302  
3303          $table_parts = explode( '.', $table );
3304          $table       = '`' . implode( '`.`', $table_parts ) . '`';
3305          $results     = $this->get_results( "SHOW FULL COLUMNS FROM $table" );
3306          if ( ! $results ) {
3307              return new WP_Error( 'wpdb_get_table_charset_failure', __( 'Could not retrieve table charset.' ) );
3308          }
3309  
3310          foreach ( $results as $column ) {
3311              $columns[ strtolower( $column->Field ) ] = $column;
3312          }
3313  
3314          $this->col_meta[ $tablekey ] = $columns;
3315  
3316          foreach ( $columns as $column ) {
3317              if ( ! empty( $column->Collation ) ) {
3318                  list( $charset ) = explode( '_', $column->Collation );
3319  
3320                  $charsets[ strtolower( $charset ) ] = true;
3321              }
3322  
3323              list( $type ) = explode( '(', $column->Type );
3324  
3325              // A binary/blob means the whole query gets treated like this.
3326              if ( in_array( strtoupper( $type ), array( 'BINARY', 'VARBINARY', 'TINYBLOB', 'MEDIUMBLOB', 'BLOB', 'LONGBLOB' ), true ) ) {
3327                  $this->table_charset[ $tablekey ] = 'binary';
3328                  return 'binary';
3329              }
3330          }
3331  
3332          // utf8mb3 is an alias for utf8.
3333          if ( isset( $charsets['utf8mb3'] ) ) {
3334              $charsets['utf8'] = true;
3335              unset( $charsets['utf8mb3'] );
3336          }
3337  
3338          // Check if we have more than one charset in play.
3339          $count = count( $charsets );
3340          if ( 1 === $count ) {
3341              $charset = key( $charsets );
3342          } elseif ( 0 === $count ) {
3343              // No charsets, assume this table can store whatever.
3344              $charset = false;
3345          } else {
3346              // More than one charset. Remove latin1 if present and recalculate.
3347              unset( $charsets['latin1'] );
3348              $count = count( $charsets );
3349              if ( 1 === $count ) {
3350                  // Only one charset (besides latin1).
3351                  $charset = key( $charsets );
3352              } elseif ( 2 === $count && isset( $charsets['utf8'], $charsets['utf8mb4'] ) ) {
3353                  // Two charsets, but they're utf8 and utf8mb4, use utf8.
3354                  $charset = 'utf8';
3355              } else {
3356                  // Two mixed character sets. ascii.
3357                  $charset = 'ascii';
3358              }
3359          }
3360  
3361          $this->table_charset[ $tablekey ] = $charset;
3362          return $charset;
3363      }
3364  
3365      /**
3366       * Retrieves the character set for the given column.
3367       *
3368       * @since 4.2.0
3369       *
3370       * @param string $table  Table name.
3371       * @param string $column Column name.
3372       * @return string|false|WP_Error Column character set as a string. False if the column has
3373       *                               no character set. WP_Error object if there was an error.
3374       */
3375  	public function get_col_charset( $table, $column ) {
3376          $tablekey  = strtolower( $table );
3377          $columnkey = strtolower( $column );
3378  
3379          /**
3380           * Filters the column charset value before the DB is checked.
3381           *
3382           * Passing a non-null value to the filter will short-circuit
3383           * checking the DB for the charset, returning that value instead.
3384           *
3385           * @since 4.2.0
3386           *
3387           * @param string|null|false|WP_Error $charset The character set to use. Default null.
3388           * @param string                     $table   The name of the table being checked.
3389           * @param string                     $column  The name of the column being checked.
3390           */
3391          $charset = apply_filters( 'pre_get_col_charset', null, $table, $column );
3392          if ( null !== $charset ) {
3393              return $charset;
3394          }
3395  
3396          // Skip this entirely if this isn't a MySQL database.
3397          if ( empty( $this->is_mysql ) ) {
3398              return false;
3399          }
3400  
3401          if ( empty( $this->table_charset[ $tablekey ] ) ) {
3402              // This primes column information for us.
3403              $table_charset = $this->get_table_charset( $table );
3404              if ( is_wp_error( $table_charset ) ) {
3405                  return $table_charset;
3406              }
3407          }
3408  
3409          // If still no column information, return the table charset.
3410          if ( empty( $this->col_meta[ $tablekey ] ) ) {
3411              return $this->table_charset[ $tablekey ];
3412          }
3413  
3414          // If this column doesn't exist, return the table charset.
3415          if ( empty( $this->col_meta[ $tablekey ][ $columnkey ] ) ) {
3416              return $this->table_charset[ $tablekey ];
3417          }
3418  
3419          // Return false when it's not a string column.
3420          if ( empty( $this->col_meta[ $tablekey ][ $columnkey ]->Collation ) ) {
3421              return false;
3422          }
3423  
3424          list( $charset ) = explode( '_', $this->col_meta[ $tablekey ][ $columnkey ]->Collation );
3425          return $charset;
3426      }
3427  
3428      /**
3429       * Retrieves the maximum string length allowed in a given column.
3430       *
3431       * The length may either be specified as a byte length or a character length.
3432       *
3433       * @since 4.2.1
3434       *
3435       * @param string $table  Table name.
3436       * @param string $column Column name.
3437       * @return array|false|WP_Error {
3438       *     Array of column length information, false if the column has no length (for
3439       *     example, numeric column), WP_Error object if there was an error.
3440       *
3441       *     @type string $type   One of 'byte' or 'char'.
3442       *     @type int    $length The column length.
3443       * }
3444       */
3445  	public function get_col_length( $table, $column ) {
3446          $tablekey  = strtolower( $table );
3447          $columnkey = strtolower( $column );
3448  
3449          // Skip this entirely if this isn't a MySQL database.
3450          if ( empty( $this->is_mysql ) ) {
3451              return false;
3452          }
3453  
3454          if ( empty( $this->col_meta[ $tablekey ] ) ) {
3455              // This primes column information for us.
3456              $table_charset = $this->get_table_charset( $table );
3457              if ( is_wp_error( $table_charset ) ) {
3458                  return $table_charset;
3459              }
3460          }
3461  
3462          if ( empty( $this->col_meta[ $tablekey ][ $columnkey ] ) ) {
3463              return false;
3464          }
3465  
3466          $typeinfo = explode( '(', $this->col_meta[ $tablekey ][ $columnkey ]->Type );
3467  
3468          $type = strtolower( $typeinfo[0] );
3469          if ( ! empty( $typeinfo[1] ) ) {
3470              $length = trim( $typeinfo[1], ')' );
3471          } else {
3472              $length = false;
3473          }
3474  
3475          switch ( $type ) {
3476              case 'char':
3477              case 'varchar':
3478                  return array(
3479                      'type'   => 'char',
3480                      'length' => (int) $length,
3481                  );
3482  
3483              case 'binary':
3484              case 'varbinary':
3485                  return array(
3486                      'type'   => 'byte',
3487                      'length' => (int) $length,
3488                  );
3489  
3490              case 'tinyblob':
3491              case 'tinytext':
3492                  return array(
3493                      'type'   => 'byte',
3494                      'length' => 255,        // 2^8 - 1
3495                  );
3496  
3497              case 'blob':
3498              case 'text':
3499                  return array(
3500                      'type'   => 'byte',
3501                      'length' => 65535,      // 2^16 - 1
3502                  );
3503  
3504              case 'mediumblob':
3505              case 'mediumtext':
3506                  return array(
3507                      'type'   => 'byte',
3508                      'length' => 16777215,   // 2^24 - 1
3509                  );
3510  
3511              case 'longblob':
3512              case 'longtext':
3513                  return array(
3514                      'type'   => 'byte',
3515                      'length' => 4294967295, // 2^32 - 1
3516                  );
3517  
3518              default:
3519                  return false;
3520          }
3521      }
3522  
3523      /**
3524       * Checks if a string is ASCII.
3525       *
3526       * The negative regex is faster for non-ASCII strings, as it allows
3527       * the search to finish as soon as it encounters a non-ASCII character.
3528       *
3529       * @since 4.2.0
3530       *
3531       * @param string $input_string String to check.
3532       * @return bool True if ASCII, false if not.
3533       */
3534  	protected function check_ascii( $input_string ) {
3535          if ( function_exists( 'mb_check_encoding' ) ) {
3536              if ( mb_check_encoding( $input_string, 'ASCII' ) ) {
3537                  return true;
3538              }
3539          } elseif ( ! preg_match( '/[^\x00-\x7F]/', $input_string ) ) {
3540              return true;
3541          }
3542  
3543          return false;
3544      }
3545  
3546      /**
3547       * Checks if the query is accessing a collation considered safe.
3548       *
3549       * @since 4.2.0
3550       *
3551       * @param string $query The query to check.
3552       * @return bool True if the collation is safe, false if it isn't.
3553       */
3554  	protected function check_safe_collation( $query ) {
3555          if ( $this->checking_collation ) {
3556              return true;
3557          }
3558  
3559          // We don't need to check the collation for queries that don't read data.
3560          $query = ltrim( $query, "\r\n\t (" );
3561          if ( preg_match( '/^(?:SHOW|DESCRIBE|DESC|EXPLAIN|CREATE)\s/i', $query ) ) {
3562              return true;
3563          }
3564  
3565          // All-ASCII queries don't need extra checking.
3566          if ( $this->check_ascii( $query ) ) {
3567              return true;
3568          }
3569  
3570          $table = $this->get_table_from_query( $query );
3571          if ( ! $table ) {
3572              return false;
3573          }
3574  
3575          $this->checking_collation = true;
3576          $collation                = $this->get_table_charset( $table );
3577          $this->checking_collation = false;
3578  
3579          // Tables with no collation, or latin1 only, don't need extra checking.
3580          if ( false === $collation || 'latin1' === $collation ) {
3581              return true;
3582          }
3583  
3584          $table = strtolower( $table );
3585          if ( empty( $this->col_meta[ $table ] ) ) {
3586              return false;
3587          }
3588  
3589          // If any of the columns don't have one of these collations, it needs more confidence checking.
3590          $safe_collations = array(
3591              'utf8_bin',
3592              'utf8_general_ci',
3593              'utf8mb3_bin',
3594              'utf8mb3_general_ci',
3595              'utf8mb4_bin',
3596              'utf8mb4_general_ci',
3597          );
3598  
3599          foreach ( $this->col_meta[ $table ] as $col ) {
3600              if ( empty( $col->Collation ) ) {
3601                  continue;
3602              }
3603  
3604              if ( ! in_array( $col->Collation, $safe_collations, true ) ) {
3605                  return false;
3606              }
3607          }
3608  
3609          return true;
3610      }
3611  
3612      /**
3613       * Strips any invalid characters based on value/charset pairs.
3614       *
3615       * @since 4.2.0
3616       *
3617       * @param array $data Array of value arrays. Each value array has the keys 'value', 'charset', and 'length'.
3618       *                    An optional 'ascii' key can be set to false to avoid redundant ASCII checks.
3619       * @return array|WP_Error The $data parameter, with invalid characters removed from each value.
3620       *                        This works as a passthrough: any additional keys such as 'field' are
3621       *                        retained in each value array. If we cannot remove invalid characters,
3622       *                        a WP_Error object is returned.
3623       */
3624  	protected function strip_invalid_text( $data ) {
3625          $db_check_string = false;
3626  
3627          foreach ( $data as &$value ) {
3628              $charset = $value['charset'];
3629  
3630              if ( is_array( $value['length'] ) ) {
3631                  $length                  = $value['length']['length'];
3632                  $truncate_by_byte_length = 'byte' === $value['length']['type'];
3633              } else {
3634                  $length = false;
3635                  /*
3636                   * Since we have no length, we'll never truncate. Initialize the variable to false.
3637                   * True would take us through an unnecessary (for this case) codepath below.
3638                   */
3639                  $truncate_by_byte_length = false;
3640              }
3641  
3642              // There's no charset to work with.
3643              if ( false === $charset ) {
3644                  continue;
3645              }
3646  
3647              // Column isn't a string.
3648              if ( ! is_string( $value['value'] ) ) {
3649                  continue;
3650              }
3651  
3652              $needs_validation = true;
3653              if (
3654                  // latin1 can store any byte sequence.
3655                  'latin1' === $charset
3656              ||
3657                  // ASCII is always OK.
3658                  ( ! isset( $value['ascii'] ) && $this->check_ascii( $value['value'] ) )
3659              ) {
3660                  $truncate_by_byte_length = true;
3661                  $needs_validation        = false;
3662              }
3663  
3664              if ( $truncate_by_byte_length ) {
3665                  mbstring_binary_safe_encoding();
3666                  if ( false !== $length && strlen( $value['value'] ) > $length ) {
3667                      $value['value'] = substr( $value['value'], 0, $length );
3668                  }
3669                  reset_mbstring_encoding();
3670  
3671                  if ( ! $needs_validation ) {
3672                      continue;
3673                  }
3674              }
3675  
3676              // utf8 can be handled by regex, which is a bunch faster than a DB lookup.
3677              if ( ( 'utf8' === $charset || 'utf8mb3' === $charset || 'utf8mb4' === $charset ) && function_exists( 'mb_strlen' ) ) {
3678                  $regex = '/
3679                      (
3680                          (?: [\x00-\x7F]                  # single-byte sequences   0xxxxxxx
3681                          |   [\xC2-\xDF][\x80-\xBF]       # double-byte sequences   110xxxxx 10xxxxxx
3682                          |   \xE0[\xA0-\xBF][\x80-\xBF]   # triple-byte sequences   1110xxxx 10xxxxxx * 2
3683                          |   [\xE1-\xEC][\x80-\xBF]{2}
3684                          |   \xED[\x80-\x9F][\x80-\xBF]
3685                          |   [\xEE-\xEF][\x80-\xBF]{2}';
3686  
3687                  if ( 'utf8mb4' === $charset ) {
3688                      $regex .= '
3689                          |    \xF0[\x90-\xBF][\x80-\xBF]{2} # four-byte sequences   11110xxx 10xxxxxx * 3
3690                          |    [\xF1-\xF3][\x80-\xBF]{3}
3691                          |    \xF4[\x80-\x8F][\x80-\xBF]{2}
3692                      ';
3693                  }
3694  
3695                  $regex         .= '){1,40}                          # ...one or more times
3696                      )
3697                      | .                                  # anything else
3698                      /x';
3699                  $value['value'] = preg_replace( $regex, '$1', $value['value'] );
3700  
3701                  if ( false !== $length && mb_strlen( $value['value'], 'UTF-8' ) > $length ) {
3702                      $value['value'] = mb_substr( $value['value'], 0, $length, 'UTF-8' );
3703                  }
3704                  continue;
3705              }
3706  
3707              // We couldn't use any local conversions, send it to the DB.
3708              $value['db']     = true;
3709              $db_check_string = true;
3710          }
3711          unset( $value ); // Remove by reference.
3712  
3713          if ( $db_check_string ) {
3714              $queries = array();
3715              foreach ( $data as $col => $value ) {
3716                  if ( ! empty( $value['db'] ) ) {
3717                      // We're going to need to truncate by characters or bytes, depending on the length value we have.
3718                      if ( isset( $value['length']['type'] ) && 'byte' === $value['length']['type'] ) {
3719                          // Using binary causes LEFT() to truncate by bytes.
3720                          $charset = 'binary';
3721                      } else {
3722                          $charset = $value['charset'];
3723                      }
3724  
3725                      if ( $this->charset ) {
3726                          $connection_charset = $this->charset;
3727                      } else {
3728                          $connection_charset = mysqli_character_set_name( $this->dbh );
3729                      }
3730  
3731                      if ( is_array( $value['length'] ) ) {
3732                          $length          = sprintf( '%.0f', $value['length']['length'] );
3733                          $queries[ $col ] = $this->prepare( "CONVERT( LEFT( CONVERT( %s USING $charset ), $length ) USING $connection_charset )", $value['value'] );
3734                      } elseif ( 'binary' !== $charset ) {
3735                          // If we don't have a length, there's no need to convert binary - it will always return the same result.
3736                          $queries[ $col ] = $this->prepare( "CONVERT( CONVERT( %s USING $charset ) USING $connection_charset )", $value['value'] );
3737                      }
3738  
3739                      unset( $data[ $col ]['db'] );
3740                  }
3741              }
3742  
3743              $sql = array();
3744              foreach ( $queries as $column => $query ) {
3745                  if ( ! $query ) {
3746                      continue;
3747                  }
3748  
3749                  $sql[] = $query . " AS x_$column";
3750              }
3751  
3752              $this->check_current_query = false;
3753              $row                       = $this->get_row( 'SELECT ' . implode( ', ', $sql ), ARRAY_A );
3754              if ( ! $row ) {
3755                  return new WP_Error( 'wpdb_strip_invalid_text_failure', __( 'Could not strip invalid text.' ) );
3756              }
3757  
3758              foreach ( array_keys( $data ) as $column ) {
3759                  if ( isset( $row[ "x_$column" ] ) ) {
3760                      $data[ $column ]['value'] = $row[ "x_$column" ];
3761                  }
3762              }
3763          }
3764  
3765          return $data;
3766      }
3767  
3768      /**
3769       * Strips any invalid characters from the query.
3770       *
3771       * @since 4.2.0
3772       *
3773       * @param string $query Query to convert.
3774       * @return string|WP_Error The converted query, or a WP_Error object if the conversion fails.
3775       */
3776  	protected function strip_invalid_text_from_query( $query ) {
3777          // We don't need to check the collation for queries that don't read data.
3778          $trimmed_query = ltrim( $query, "\r\n\t (" );
3779          if ( preg_match( '/^(?:SHOW|DESCRIBE|DESC|EXPLAIN|CREATE)\s/i', $trimmed_query ) ) {
3780              return $query;
3781          }
3782  
3783          $table = $this->get_table_from_query( $query );
3784          if ( $table ) {
3785              $charset = $this->get_table_charset( $table );
3786              if ( is_wp_error( $charset ) ) {
3787                  return $charset;
3788              }
3789  
3790              // We can't reliably strip text from tables containing binary/blob columns.
3791              if ( 'binary' === $charset ) {
3792                  return $query;
3793              }
3794          } else {
3795              $charset = $this->charset;
3796          }
3797  
3798          $data = array(
3799              'value'   => $query,
3800              'charset' => $charset,
3801              'ascii'   => false,
3802              'length'  => false,
3803          );
3804  
3805          $data = $this->strip_invalid_text( array( $data ) );
3806          if ( is_wp_error( $data ) ) {
3807              return $data;
3808          }
3809  
3810          return $data[0]['value'];
3811      }
3812  
3813      /**
3814       * Strips any invalid characters from the string for a given table and column.
3815       *
3816       * @since 4.2.0
3817       *
3818       * @param string $table  Table name.
3819       * @param string $column Column name.
3820       * @param string $value  The text to check.
3821       * @return string|WP_Error The converted string, or a WP_Error object if the conversion fails.
3822       */
3823  	public function strip_invalid_text_for_column( $table, $column, $value ) {
3824          if ( ! is_string( $value ) ) {
3825              return $value;
3826          }
3827  
3828          $charset = $this->get_col_charset( $table, $column );
3829          if ( ! $charset ) {
3830              // Not a string column.
3831              return $value;
3832          } elseif ( is_wp_error( $charset ) ) {
3833              // Bail on real errors.
3834              return $charset;
3835          }
3836  
3837          $data = array(
3838              $column => array(
3839                  'value'   => $value,
3840                  'charset' => $charset,
3841                  'length'  => $this->get_col_length( $table, $column ),
3842              ),
3843          );
3844  
3845          $data = $this->strip_invalid_text( $data );
3846          if ( is_wp_error( $data ) ) {
3847              return $data;
3848          }
3849  
3850          return $data[ $column ]['value'];
3851      }
3852  
3853      /**
3854       * Finds the first table name referenced in a query.
3855       *
3856       * @since 4.2.0
3857       *
3858       * @param string $query The query to search.
3859       * @return string|false The table name found, or false if a table couldn't be found.
3860       */
3861  	protected function get_table_from_query( $query ) {
3862          // Remove characters that can legally trail the table name.
3863          $query = rtrim( $query, ';/-#' );
3864  
3865          // Allow (select...) union [...] style queries. Use the first query's table name.
3866          $query = ltrim( $query, "\r\n\t (" );
3867  
3868          // Strip everything between parentheses except nested selects.
3869          $query = preg_replace( '/\((?!\s*select)[^(]*?\)/is', '()', $query );
3870  
3871          // Strip any leading SET STATEMENT statements.
3872          $query = preg_replace( '/^SET STATEMENT.+?\sFOR\s+/is', '', $query );
3873  
3874          // Quickly match most common queries.
3875          if ( preg_match(
3876              '/^\s*(?:'
3877                  . 'SELECT.*?\s+FROM'
3878                  . '|INSERT(?:\s+LOW_PRIORITY|\s+DELAYED|\s+HIGH_PRIORITY)?(?:\s+IGNORE)?(?:\s+INTO)?'
3879                  . '|REPLACE(?:\s+LOW_PRIORITY|\s+DELAYED)?(?:\s+INTO)?'
3880                  . '|UPDATE(?:\s+LOW_PRIORITY)?(?:\s+IGNORE)?'
3881                  . '|DELETE(?:\s+LOW_PRIORITY|\s+QUICK|\s+IGNORE)*(?:.+?FROM)?'
3882              . ')\s+((?:[0-9a-zA-Z$_.`-]|[\xC2-\xDF][\x80-\xBF])+)/is',
3883              $query,
3884              $maybe
3885          ) ) {
3886              return str_replace( '`', '', $maybe[1] );
3887          }
3888  
3889          // SHOW TABLE STATUS and SHOW TABLES WHERE Name = 'wp_posts'
3890          if ( preg_match( '/^\s*SHOW\s+(?:TABLE\s+STATUS|(?:FULL\s+)?TABLES).+WHERE\s+Name\s*=\s*("|\')((?:[0-9a-zA-Z$_.-]|[\xC2-\xDF][\x80-\xBF])+)\\1/is', $query, $maybe ) ) {
3891              return $maybe[2];
3892          }
3893  
3894          /*
3895           * SHOW TABLE STATUS LIKE and SHOW TABLES LIKE 'wp\_123\_%'
3896           * This quoted LIKE operand seldom holds a full table name.
3897           * It is usually a pattern for matching a prefix so we just
3898           * strip the trailing % and unescape the _ to get 'wp_123_'
3899           * which drop-ins can use for routing these SQL statements.
3900           */
3901          if ( preg_match( '/^\s*SHOW\s+(?:TABLE\s+STATUS|(?:FULL\s+)?TABLES)\s+(?:WHERE\s+Name\s+)?LIKE\s*("|\')((?:[\\\\0-9a-zA-Z$_.-]|[\xC2-\xDF][\x80-\xBF])+)%?\\1/is', $query, $maybe ) ) {
3902              return str_replace( '\\_', '_', $maybe[2] );
3903          }
3904  
3905          // Big pattern for the rest of the table-related queries.
3906          if ( preg_match(
3907              '/^\s*(?:'
3908                  . '(?:EXPLAIN\s+(?:EXTENDED\s+)?)?SELECT.*?\s+FROM'
3909                  . '|DESCRIBE|DESC|EXPLAIN|HANDLER'
3910                  . '|(?:LOCK|UNLOCK)\s+TABLE(?:S)?'
3911                  . '|(?:RENAME|OPTIMIZE|BACKUP|RESTORE|CHECK|CHECKSUM|ANALYZE|REPAIR).*\s+TABLE'
3912                  . '|TRUNCATE(?:\s+TABLE)?'
3913                  . '|CREATE(?:\s+TEMPORARY)?\s+TABLE(?:\s+IF\s+NOT\s+EXISTS)?'
3914                  . '|ALTER(?:\s+IGNORE)?\s+TABLE'
3915                  . '|DROP\s+TABLE(?:\s+IF\s+EXISTS)?'
3916                  . '|CREATE(?:\s+\w+)?\s+INDEX.*\s+ON'
3917                  . '|DROP\s+INDEX.*\s+ON'
3918                  . '|LOAD\s+DATA.*INFILE.*INTO\s+TABLE'
3919                  . '|(?:GRANT|REVOKE).*ON\s+TABLE'
3920                  . '|SHOW\s+(?:.*FROM|.*TABLE)'
3921              . ')\s+\(*\s*((?:[0-9a-zA-Z$_.`-]|[\xC2-\xDF][\x80-\xBF])+)\s*\)*/is',
3922              $query,
3923              $maybe
3924          ) ) {
3925              return str_replace( '`', '', $maybe[1] );
3926          }
3927  
3928          return false;
3929      }
3930  
3931      /**
3932       * Loads the column metadata from the last query.
3933       *
3934       * @since 3.5.0
3935       */
3936  	protected function load_col_info() {
3937          if ( $this->col_info ) {
3938              return;
3939          }
3940  
3941          $num_fields = mysqli_num_fields( $this->result );
3942  
3943          for ( $i = 0; $i < $num_fields; $i++ ) {
3944              $this->col_info[ $i ] = mysqli_fetch_field( $this->result );
3945          }
3946      }
3947  
3948      /**
3949       * Retrieves column metadata from the last query.
3950       *
3951       * @since 0.71
3952       *
3953       * @param string $info_type  Optional. Possible values include 'name', 'table', 'def', 'max_length',
3954       *                           'not_null', 'primary_key', 'multiple_key', 'unique_key', 'numeric',
3955       *                           'blob', 'type', 'unsigned', 'zerofill'. Default 'name'.
3956       * @param int    $col_offset Optional. 0: col name. 1: which table the col's in. 2: col's max length.
3957       *                           3: if the col is numeric. 4: col's type. Default -1.
3958       * @return mixed Column results.
3959       */
3960  	public function get_col_info( $info_type = 'name', $col_offset = -1 ) {
3961          $this->load_col_info();
3962  
3963          if ( $this->col_info ) {
3964              if ( -1 === $col_offset ) {
3965                  $i         = 0;
3966                  $new_array = array();
3967                  foreach ( (array) $this->col_info as $col ) {
3968                      $new_array[ $i ] = $col->{$info_type};
3969                      ++$i;
3970                  }
3971                  return $new_array;
3972              } else {
3973                  return $this->col_info[ $col_offset ]->{$info_type};
3974              }
3975          }
3976  
3977          return null;
3978      }
3979  
3980      /**
3981       * Starts the timer, for debugging purposes.
3982       *
3983       * @since 1.5.0
3984       *
3985       * @return true
3986       */
3987  	public function timer_start() {
3988          $this->time_start = microtime( true );
3989          return true;
3990      }
3991  
3992      /**
3993       * Stops the debugging timer.
3994       *
3995       * @since 1.5.0
3996       *
3997       * @return float Total time spent on the query, in seconds.
3998       */
3999  	public function timer_stop() {
4000          return ( microtime( true ) - $this->time_start );
4001      }
4002  
4003      /**
4004       * Wraps errors in a nice header and footer and dies.
4005       *
4006       * Will not die if wpdb::$show_errors is false.
4007       *
4008       * @since 1.5.0
4009       *
4010       * @param string $message    The error message.
4011       * @param string $error_code Optional. A computer-readable string to identify the error.
4012       *                           Default '500'.
4013       * @return false False if the showing of errors is disabled.
4014       */
4015  	public function bail( $message, $error_code = '500' ) {
4016          if ( $this->show_errors ) {
4017              $error = '';
4018  
4019              if ( $this->dbh instanceof mysqli ) {
4020                  $error = mysqli_error( $this->dbh );
4021              } elseif ( mysqli_connect_errno() ) {
4022                  $error = mysqli_connect_error();
4023              }
4024  
4025              if ( $error ) {
4026                  $message = '<p><code>' . $error . "</code></p>\n" . $message;
4027              }
4028  
4029              wp_die( $message );
4030          } else {
4031              if ( class_exists( 'WP_Error', false ) ) {
4032                  $this->error = new WP_Error( $error_code, $message );
4033              } else {
4034                  $this->error = $message;
4035              }
4036  
4037              return false;
4038          }
4039      }
4040  
4041      /**
4042       * Closes the current database connection.
4043       *
4044       * @since 4.5.0
4045       *
4046       * @return bool True if the connection was successfully closed,
4047       *              false if it wasn't, or if the connection doesn't exist.
4048       */
4049  	public function close() {
4050          if ( ! $this->dbh ) {
4051              return false;
4052          }
4053  
4054          $closed = mysqli_close( $this->dbh );
4055  
4056          if ( $closed ) {
4057              $this->dbh           = null;
4058              $this->ready         = false;
4059              $this->has_connected = false;
4060          }
4061  
4062          return $closed;
4063      }
4064  
4065      /**
4066       * Determines whether the database server is at least the required minimum version.
4067       *
4068       * @since 2.5.0
4069       *
4070       * @global string $required_mysql_version The minimum required MySQL version string.
4071       * @return WP_Error|null
4072       */
4073  	public function check_database_version() {
4074          global $required_mysql_version;
4075          $wp_version = wp_get_wp_version();
4076  
4077          // Make sure the server has the required MySQL version.
4078          if ( version_compare( $this->db_version(), $required_mysql_version, '<' ) ) {
4079              /* translators: 1: WordPress version number, 2: Minimum required MySQL version number. */
4080              return new WP_Error( 'database_version', sprintf( __( '<strong>Error:</strong> WordPress %1$s requires MySQL %2$s or higher' ), $wp_version, $required_mysql_version ) );
4081          }
4082  
4083          return null;
4084      }
4085  
4086      /**
4087       * Determines whether the database supports collation.
4088       *
4089       * Called when WordPress is generating the table scheme.
4090       *
4091       * Use `wpdb::has_cap( 'collation' )`.
4092       *
4093       * @since 2.5.0
4094       * @deprecated 3.5.0 Use wpdb::has_cap()
4095       *
4096       * @return bool True if collation is supported, false if not.
4097       */
4098  	public function supports_collation() {
4099          _deprecated_function( __FUNCTION__, '3.5.0', 'wpdb::has_cap( \'collation\' )' );
4100          return $this->has_cap( 'collation' );
4101      }
4102  
4103      /**
4104       * Retrieves the database character collate.
4105       *
4106       * @since 3.5.0
4107       *
4108       * @return string The database character collate.
4109       */
4110  	public function get_charset_collate() {
4111          $charset_collate = '';
4112  
4113          if ( ! empty( $this->charset ) ) {
4114              $charset_collate = "DEFAULT CHARACTER SET $this->charset";
4115          }
4116          if ( ! empty( $this->collate ) ) {
4117              $charset_collate .= " COLLATE $this->collate";
4118          }
4119  
4120          return $charset_collate;
4121      }
4122  
4123      /**
4124       * Determines whether the database or WPDB supports a particular feature.
4125       *
4126       * Capability sniffs for the database server and current version of WPDB.
4127       *
4128       * Database sniffs are based on the version of the database server in use.
4129       *
4130       * WPDB sniffs are added as new features are introduced to allow theme and plugin
4131       * developers to determine feature support. This is to account for drop-ins which may
4132       * introduce feature support at a different time to WordPress.
4133       *
4134       * @since 2.7.0
4135       * @since 4.1.0 Added support for the 'utf8mb4' feature.
4136       * @since 4.6.0 Added support for the 'utf8mb4_520' feature.
4137       * @since 6.2.0 Added support for the 'identifier_placeholders' feature.
4138       * @since 6.6.0 The `utf8mb4` feature now always returns true.
4139       *
4140       * @see wpdb::db_version()
4141       *
4142       * @param string $db_cap The feature to check for. Accepts 'collation', 'group_concat',
4143       *                       'subqueries', 'set_charset', 'utf8mb4', 'utf8mb4_520',
4144       *                       or 'identifier_placeholders'.
4145       * @return bool True when the database feature is supported, false otherwise.
4146       */
4147  	public function has_cap( $db_cap ) {
4148          $db_version     = $this->db_version();
4149          $db_server_info = $this->db_server_info();
4150  
4151          /*
4152           * Account for MariaDB version being prefixed with '5.5.5-' on older PHP versions.
4153           *
4154           * Note: str_contains() is not used here, as this file can be included
4155           * directly outside of WordPress core, e.g. by HyperDB, in which case
4156           * the polyfills from wp-includes/compat.php are not loaded.
4157           */
4158          if ( '5.5.5' === $db_version && false !== strpos( $db_server_info, 'MariaDB' )
4159              && ( PHP_VERSION_ID <= 80015 // PHP 8.0.15 or older.
4160                  || 80100 <= PHP_VERSION_ID && PHP_VERSION_ID <= 80102 ) // PHP 8.1.0 to PHP 8.1.2.
4161          ) {
4162              // Strip the '5.5.5-' prefix and set the version to the correct value.
4163              $db_server_info = preg_replace( '/^5\.5\.5-(.*)/', '$1', $db_server_info );
4164              $db_version     = preg_replace( '/[^0-9.].*/', '', $db_server_info );
4165          }
4166  
4167          switch ( strtolower( $db_cap ) ) {
4168              case 'collation':    // @since 2.5.0
4169              case 'group_concat': // @since 2.7.0
4170              case 'subqueries':   // @since 2.7.0
4171                  return version_compare( $db_version, '4.1', '>=' );
4172              case 'set_charset':
4173                  return version_compare( $db_version, '5.0.7', '>=' );
4174              case 'utf8mb4':      // @since 4.1.0
4175                  return true;
4176              case 'utf8mb4_520': // @since 4.6.0
4177                  return version_compare( $db_version, '5.6', '>=' );
4178              case 'identifier_placeholders': // @since 6.2.0
4179                  /*
4180                   * As of WordPress 6.2, wpdb::prepare() supports identifiers via '%i',
4181                   * e.g. table/field names.
4182                   */
4183                  return true;
4184          }
4185  
4186          return false;
4187      }
4188  
4189      /**
4190       * Retrieves a comma-separated list of the names of the functions that called wpdb.
4191       *
4192       * @since 2.5.0
4193       *
4194       * @return string Comma-separated list of the calling functions.
4195       */
4196  	public function get_caller() {
4197          return wp_debug_backtrace_summary( __CLASS__ );
4198      }
4199  
4200      /**
4201       * Retrieves the database server version number.
4202       *
4203       * @since 2.7.0
4204       *
4205       * @return string|null Version number on success, null on failure.
4206       */
4207  	public function db_version() {
4208          return preg_replace( '/[^0-9.].*/', '', $this->db_server_info() );
4209      }
4210  
4211      /**
4212       * Returns the raw version string of the database server.
4213       *
4214       * @since 5.5.0
4215       *
4216       * @return string Database server version as a string.
4217       */
4218  	public function db_server_info() {
4219          return mysqli_get_server_info( $this->dbh );
4220      }
4221  }


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