sqlite3-db.php

<?php
/**
 * WordPress DB Class
 *
 * Original code from {@link http://php.justinvincent.com Justin Vincent (justin@visunet.ie)}
 *
 * @package WordPress
 * @subpackage Database
 * @since 0.71
 */

/**
 * @since 0.71
 */
define( 'ARRAY_A', 'ARRAY_A' );

/**
 * @since 0.71
 */
define( 'ARRAY_N', 'ARRAY_N' );

/**
 * WordPress Database Access Abstraction Object
 *
 * It is possible to replace this class with your own
 * by setting the $wpdb global variable in wp-content/db.php
 * file to your class. The wpdb class will still be included,
 * so you can extend it or simply use your own.
 *
 * @link https://codex.wordpress.org/Function_Reference/wpdb_Class
 *
 * @package WordPress
 * @subpackage Database
 * @since 0.71
 */
class wpdb {

	/**
	 * Whether to show SQL/DB errors.
	 *
	 * Default behavior is to show errors if both WP_DEBUG and WP_DEBUG_DISPLAY
	 * evaluated to true.
	 *
	 * @since 0.71
	 * @access private
	 * @var bool
	 */
	var $show_errors = false;

	/**
	 * Whether to suppress errors during the DB bootstrapping.
	 *
	 * @access private
	 * @since 2.5.0
	 * @var bool
	 */
	var $suppress_errors = false;

	/**
	 * The last error during query.
	 *
	 * @since 2.5.0
	 * @var string
	 */
	public $last_error = '';

	/**
	 * Amount of queries made
	 *
	 * @since 1.2.0
	 * @access public
	 * @var int
	 */
	public $num_queries = 0;

	/**
	 * Count of rows returned by previous query
	 *
	 * @since 0.71
	 * @access public
	 * @var int
	 */
	public $num_rows = 0;

	/**
	 * Count of affected rows by previous query
	 *
	 * @since 0.71
	 * @access private
	 * @var int
	 */
	var $rows_affected = 0;

	/**
	 * The ID generated for an AUTO_INCREMENT column by the previous query (usually INSERT).
	 *
	 * @since 0.71
	 * @access public
	 * @var int
	 */
	public $insert_id = 0;

	/**
	 * Last query made
	 *
	 * @since 0.71
	 * @access private
	 * @var array
	 */
	var $last_query;

	/**
	 * Results of the last query made
	 *
	 * @since 0.71
	 * @access private
	 * @var array|null
	 */
	var $last_result;

	/**
	 * MySQL result, which is either a resource or boolean.
	 *
	 * @since 0.71
	 * @access protected
	 * @var mixed
	 */
	protected $result;

	/**
	 * Cached column info, for sanity checking data before inserting
	 *
	 * @since 4.2.0
	 * @access protected
	 * @var array
	 */
	protected $col_meta = array();

	/**
	 * Whether text fields in the current query need to be sanity checked.
	 *
	 * @since 4.2.0
	 * @access protected
	 * @var bool
	 */
	protected $check_current_query = true;

	/**
	 * Saved info on the table column
	 *
	 * @since 0.71
	 * @access protected
	 * @var array
	 */
	protected $col_info;

	/**
	 * Saved queries that were executed
	 *
	 * @since 1.5.0
	 * @access private
	 * @var array
	 */
	var $queries;

	/**
	 * The number of times to retry reconnecting before dying.
	 *
	 * @since 3.9.0
	 * @access protected
	 * @see wpdb::check_connection()
	 * @var int
	 */
	protected $reconnect_retries = 5;

	/**
	 * WordPress table prefix
	 *
	 * You can set this to have multiple WordPress installations
	 * in a single database. The second reason is for possible
	 * security precautions.
	 *
	 * @since 2.5.0
	 * @access public
	 * @var string
	 */
	public $prefix = '';
	public $options = 'ewwwio_options';

	/**
	 * Whether the database queries are ready to start executing.
	 *
	 * @since 2.3.2
	 * @access private
	 * @var bool
	 */
	var $ready = false;

	/**
	 * Format specifiers for DB columns. Columns not listed here default to %s. Initialized during WP load.
	 *
	 * Keys are column names, values are format types: 'ID' => '%d'
	 *
	 * @since 2.8.0
	 * @see wpdb::prepare()
	 * @see wpdb::insert()
	 * @see wpdb::update()
	 * @see wpdb::delete()
	 * @see wp_set_wpdb_vars()
	 * @access public
	 * @var array
	 */
	public $field_types = array();

	/**
	 * Database Name
	 *
	 * @since 3.1.0
	 * @access protected
	 * @var string
	 */
	protected $dbname;

	/**
	 * Database Handle
	 *
	 * @since 0.71
	 * @access protected
	 * @var string
	 */
	protected $dbh;

	/**
	 * A textual description of the last query/get_row/get_var call
	 *
	 * @since 3.0.0
	 * @access public
	 * @var string
	 */
	public $func_call;

	/**
	 * Whether MySQL is used as the database engine.
	 *
	 * Set to false, because this is sqlite.
	 *
	 * @since 3.3.0
	 * @access public
	 * @var bool
	 */
	public $is_mysql = false;

	/**
	 * Whether we've managed to successfully connect at some point
	 *
	 * @since 3.9.0
	 * @access private
	 * @var bool
	 */
	private $has_connected = false;

	/**
	 * Loads a database
	 *
	 * PHP5 style constructor for compatibility with PHP5. Does
	 * the actual setting up of the class properties and connection
	 * to the database.
	 *
	 * @link https://core.trac.wordpress.org/ticket/3354
	 * @since 2.0.8
	 *
	 * @global string $wp_version
	 *
	 * @param string $dbname     MySQL database name
	 */
	public function __construct( $dbname ) {
		register_shutdown_function( array( $this, '__destruct' ) );


		/* Use ext/mysqli if it exists and:
		 *  - WP_USE_EXT_MYSQL is defined as false, or
		 *  - We are a development version of WordPress, or
		 *  - We are running PHP 5.5 or greater, or
		 *  - ext/mysql is not loaded.
		 */
		if ( ! class_exists( 'SQLite3' ) ) {
			$this->dbname = false;
			$this->ready = false;
			$this->dbh = false;
			return;
		}

		$this->dbname = $dbname;

		$this->db_connect();
	}

	/**
	 * PHP5 style destructor and will run when database object is destroyed.
	 *
	 * @see wpdb::__construct()
	 * @since 2.0.8
	 * @return true
	 */
	public function __destruct() {
		return true;
	}

	/**
	 * Real escape, using mysqli_real_escape_string() or mysql_real_escape_string()
	 *
	 * @see mysqli_real_escape_string()
	 * @see mysql_real_escape_string()
	 * @since 2.8.0
	 * @access private
	 *
	 * @param  string $string to escape
	 * @return string escaped
	 */
	function _real_escape( $string ) {
		if ( $this->dbh ) {
			return $this->dbh->escapeString( $string );
		}

		return addslashes( $string );
	}

	/**
	 * Escape data. Works on arrays.
	 *
	 * @uses wpdb::_real_escape()
	 * @since  2.8.0
	 * @access private
	 *
	 * @param  string|array $data
	 * @return string|array escaped
	 */
	function _escape( $data ) {
		if ( is_array( $data ) ) {
			foreach ( $data as $k => $v ) {
				if ( is_array($v) )
					$data[$k] = $this->_escape( $v );
				else
					$data[$k] = $this->_real_escape( $v );
			}
		} else {
			$data = $this->_real_escape( $data );
		}

		return $data;
	}

	/**
	 * Escapes content by reference for insertion into the database, for security
	 *
	 * @uses wpdb::_real_escape()
	 *
	 * @since 2.3.0
	 *
	 * @param string $string to escape
	 */
	public function escape_by_ref( &$string ) {
		if ( ! is_float( $string ) )
			$string = $this->_real_escape( $string );
	}

	/**
	 * Prepares a SQL query for safe execution. Uses sprintf()-like syntax.
	 *
	 * The following directives can be used in the query format string:
	 *   %d (integer)
	 *   %f (float)
	 *   %s (string)
	 *   %% (literal percentage sign - no argument needed)
	 *
	 * All of %d, %f, and %s are to be left unquoted in the query string and they need an argument passed for them.
	 * Literals (%) as parts of the query must be properly written as %%.
	 *
	 * This function only supports a small subset of the sprintf syntax; it only supports %d (integer), %f (float), and %s (string).
	 * Does not support sign, padding, alignment, width or precision specifiers.
	 * Does not support argument numbering/swapping.
	 *
	 * May be called like {@link https://secure.php.net/sprintf sprintf()} or like {@link https://secure.php.net/vsprintf vsprintf()}.
	 *
	 * Both %d and %s should be left unquoted in the query string.
	 *
	 *     wpdb::prepare( "SELECT * FROM `table` WHERE `column` = %s AND `field` = %d", 'foo', 1337 )
	 *     wpdb::prepare( "SELECT DATE_FORMAT(`field`, '%%c') FROM `table` WHERE `column` = %s", 'foo' );
	 *
	 * @link https://secure.php.net/sprintf Description of syntax.
	 * @since 2.3.0
	 *
	 * @param string      $query    Query statement with sprintf()-like placeholders
	 * @param array|mixed $args     The array of variables to substitute into the query's placeholders if being called like
	 *                              {@link https://secure.php.net/vsprintf vsprintf()}, or the first variable to substitute into the query's placeholders if
	 *                              being called like {@link https://secure.php.net/sprintf sprintf()}.
	 * @param mixed       $args,... further variables to substitute into the query's placeholders if being called like
	 *                              {@link https://secure.php.net/sprintf sprintf()}.
	 * @return string|void Sanitized query string, if there is a query to prepare.
	 */
	public function prepare( $query, $args ) {
		if ( is_null( $query ) )
			return;

		// This is not meant to be foolproof -- but it will catch obviously incorrect usage.
		if ( strpos( $query, '%' ) === false ) {
			_doing_it_wrong( 'wpdb::prepare', sprintf( __( 'The query argument of %s must have a placeholder.' ), 'wpdb::prepare()' ), '3.9.0' );
		}

		$args = func_get_args();
		array_shift( $args );
		// If args were passed as an array (as in vsprintf), move them up
		if ( isset( $args[0] ) && is_array($args[0]) )
			$args = $args[0];
		$query = str_replace( "'%s'", '%s', $query ); // in case someone mistakenly already singlequoted it
		$query = str_replace( '"%s"', '%s', $query ); // doublequote unquoting
		$query = preg_replace( '|(?<!%)%f|' , '%F', $query ); // Force floats to be locale unaware
		$query = preg_replace( '|(?<!%)%s|', "'%s'", $query ); // quote the strings, avoiding escaped strings like %%s
		array_walk( $args, array( $this, 'escape_by_ref' ) );
		return @vsprintf( $query, $args );
	}

	/**
	 * Print SQL/DB error.
	 *
	 * @since 0.71
	 * @global array $EZSQL_ERROR Stores error information of query and error string
	 *
	 * @param string $str The error to display
	 * @return false|void False if the showing of errors is disabled.
	 */
	public function print_error( $str = '' ) {
		global $EZSQL_ERROR;

		if ( ! $str ) {
			$str = $this->dbh->lastErrorMsg();
		}
		$EZSQL_ERROR[] = array( 'query' => $this->last_query, 'error_str' => $str );

		if ( $this->suppress_errors )
			return false;


		$error_str = sprintf( __( 'EWWWIO database error %1$s for query %2$s' ), $str, $this->last_query );

		error_log( $error_str );

		// Are we showing errors?
		if ( ! $this->show_errors )
			return false;

		$str   = htmlspecialchars( $str, ENT_QUOTES );
		$query = htmlspecialchars( $this->last_query, ENT_QUOTES );

		printf(
			'<div id="error"><p class="ewwwiodberror"><strong>%s</strong> [%s]<br /><code>%s</code></p></div>',
			__( 'EWWWIO database error:' ),
			$str,
			$query
		);
	}

	/**
	 * Enables showing of database errors.
	 *
	 * This function should be used only to enable showing of errors.
	 * wpdb::hide_errors() should be used instead for hiding of errors. However,
	 * this function can be used to enable and disable showing of database
	 * errors.
	 *
	 * @since 0.71
	 * @see wpdb::hide_errors()
	 *
	 * @param bool $show Whether to show or hide errors
	 * @return bool Old value for showing errors.
	 */
	public function show_errors( $show = true ) {
		$errors = $this->show_errors;
		$this->show_errors = $show;
		return $errors;
	}

	/**
	 * Disables showing of database errors.
	 *
	 * By default database errors are not shown.
	 *
	 * @since 0.71
	 * @see wpdb::show_errors()
	 *
	 * @return bool Whether showing of errors was active
	 */
	public function hide_errors() {
		$show = $this->show_errors;
		$this->show_errors = false;
		return $show;
	}

	/**
	 * Whether to suppress database errors.
	 *
	 * By default database errors are suppressed, with a simple
	 * call to this function they can be enabled.
	 *
	 * @since 2.5.0
	 * @see wpdb::hide_errors()
	 * @param bool $suppress Optional. New value. Defaults to true.
	 * @return bool Old value
	 */
	public function suppress_errors( $suppress = true ) {
		$errors = $this->suppress_errors;
		$this->suppress_errors = (bool) $suppress;
		return $errors;
	}

	/**
	 * Kill cached query results.
	 *
	 * @since 0.71
	 */
	public function flush() {
		$this->last_result = array();
		$this->col_info    = null;
		$this->last_query  = null;
		$this->rows_affected = $this->num_rows = 0;
		$this->last_error  = '';

		if ( $this->result instanceof SQLite3Result ) {
			$this->result->finalize();
		}
		$this->result = null;
	}

	/**
	 * Connect to and select database.
	 *
	 * If $allow_bail is false, the lack of database connection will need
	 * to be handled manually.
	 *
	 * @since 3.0.0
	 * @since 3.9.0 $allow_bail parameter added.
	 *
	 * @param bool $allow_bail Optional. Allows the function to bail. Default true.
	 * @return bool True with a successful connection, false on failure.
	 */
	public function db_connect( $allow_bail = true ) {

		$this->dbh = new SQLite3( $this->dbname );

		if ( ! $this->dbh ) {
			wp_load_translations_early();

			ewwwio_debug_message( 'Error establishing a database connection' );

			return false;
		} elseif ( $this->dbh ) {

			$this->has_connected = true;

			$this->ready = true;

			return true;
		}
		return false;
	}

	/**
	 * Checks that the connection to the database is still up. If not, try to reconnect.
	 *
	 * If this function is unable to reconnect, it will forcibly die, or if after the
	 * the {@see 'template_redirect'} hook has been fired, return false instead.
	 *
	 * If $allow_bail is false, the lack of database connection will need
	 * to be handled manually.
	 *
	 * @since 3.9.0
	 *
	 * @param bool $allow_bail Optional. Allows the function to bail. Default true.
	 * @return bool|void True if the connection is up.
	 */
	public function check_connection( $allow_bail = true ) {
		if ( ! empty( $this->dbh ) ) {
			return true;
		}
		$this->db_connect();
		if ( empty( $this->dbh ) ) {
			return false;
		}
	}

	/**
	 * Perform a MySQL database query, using current database connection.
	 *
	 * More information can be found on the codex page.
	 *
	 * @since 0.71
	 *
	 * @param string $query Database query
	 * @return int|false Number of rows affected/selected or false on error
	 */
	public function query( $query ) {
		if ( ! $this->ready ) {
			$this->check_current_query = true;
			return false;
		}

		$this->flush();
		$this->func_call = "\$db->query(\"$query\")";

		$this->check_current_query = true;

		// Keep track of the last query for debug.
		$this->last_query = $query;

		$this->_do_query( $query );

		// check for query errors.
		$sql_errno = 0;
		if ( ! empty( $this->dbh ) ) {
			if ( $this->dbh instanceof SQLite3 ) {
				$sql_errno = $this->dbh->lastErrorCode();
			} else {
				// $dbh is defined, but isn't a real connection.
				// Something has gone horribly wrong, let's try a reconnect.
				$sql_errno = 1;
			}
		}

		if ( empty( $this->dbh ) || 1 == $sql_errno ) {
			if ( $this->check_connection() ) {
				$this->_do_query( $query );
			} else {
				$this->insert_id = 0;
				return false;
			}
		}

		// If there is an error then take note of it.
		if ( $this->dbh instanceof SQLite3 && $sql_errno ) {
			$this->last_error = $this->dbh->lastErrorMsg();
		} elseif ( $sql_errno ) {
			$this->last_error = __( 'Unable to retrieve the error message from SQLite' );
		}

		if ( $this->last_error ) {
			// Clear insert_id on a subsequent failed insert.
			if ( $this->insert_id && preg_match( '/^\s*(insert|replace)\s/i', $query ) )
				$this->insert_id = 0;

			$this->print_error();
			return false;
		}

		if ( preg_match( '/^\s*(create|alter|truncate|drop)\s/i', $query ) ) {
			$return_val = $this->result;
		} elseif ( preg_match( '/^\s*(insert|delete|update|replace)\s/i', $query ) ) {
			$this->rows_affected = $this->dbh->changes();
			// Take note of the insert_id
			if ( preg_match( '/^\s*(insert|replace)\s/i', $query ) ) {
				$this->insert_id = $this->dbh->lastInsertRowID();
			}
			// Return number of rows affected
			$return_val = $this->rows_affected;
		} else {
			$num_rows = 0;
			if ( $this->result instanceof SQLite3Result ) {
				while ( $row = $this->result->fetchArray( SQLITE3_ASSOC ) ) {
					$this->last_result[$num_rows] = $row;
					$num_rows++;
				}
			}

			// Log number of rows the query returned
			// and return number of rows selected
			$this->num_rows = $num_rows;
			$return_val     = $num_rows;
		}

		return $return_val;
	}

	/**
	 * Internal function to perform the mysql_query() call.
	 *
	 * @since 3.9.0
	 *
	 * @access private
	 * @see wpdb::query()
	 *
	 * @param string $query The query to run.
	 */
	private function _do_query( $query ) {
		$statement = $this->dbh->prepare( $query );
		if ( $statement instanceof SQLite3Stmt ) {
			$this->result = $statement->execute();
			$this->num_queries++;
		} else {
			$this->result = false;
		}
	}

	/**
	 * Insert a row into a table.
	 *
	 *     wpdb::insert( 'table', array( 'column' => 'foo', 'field' => 'bar' ) )
	 *     wpdb::insert( 'table', array( 'column' => 'foo', 'field' => 1337 ), array( '%s', '%d' ) )
	 *
	 * @since 2.5.0
	 * @see wpdb::prepare()
	 * @see wpdb::$field_types
	 * @see wp_set_wpdb_vars()
	 *
	 * @param string       $table  Table name
	 * @param array        $data   Data to insert (in column => value pairs).
	 *                             Both $data columns and $data values should be "raw" (neither should be SQL escaped).
	 *                             Sending a null value will cause the column to be set to NULL - the corresponding format is ignored in this case.
	 * @param array|string $format Optional. An array of formats to be mapped to each of the value in $data.
	 *                             If string, that format will be used for all of the values in $data.
	 *                             A format is one of '%d', '%f', '%s' (integer, float, string).
	 *                             If omitted, all values in $data will be treated as strings unless otherwise specified in wpdb::$field_types.
	 * @return int|false The number of rows inserted, or false on error.
	 */
	public function insert( $table, $data, $format = null ) {
		return $this->_insert_replace_helper( $table, $data, $format, 'INSERT' );
	}

	/**
	 * Replace a row into a table.
	 *
	 *     wpdb::replace( 'table', array( 'column' => 'foo', 'field' => 'bar' ) )
	 *     wpdb::replace( 'table', array( 'column' => 'foo', 'field' => 1337 ), array( '%s', '%d' ) )
	 *
	 * @since 3.0.0
	 * @see wpdb::prepare()
	 * @see wpdb::$field_types
	 * @see wp_set_wpdb_vars()
	 *
	 * @param string       $table  Table name
	 * @param array        $data   Data to insert (in column => value pairs).
	 *                             Both $data columns and $data values should be "raw" (neither should be SQL escaped).
	 *                             Sending a null value will cause the column to be set to NULL - the corresponding format is ignored in this case.
	 * @param array|string $format Optional. An array of formats to be mapped to each of the value in $data.
	 *                             If string, that format will be used for all of the values in $data.
	 *                             A format is one of '%d', '%f', '%s' (integer, float, string).
	 *                             If omitted, all values in $data will be treated as strings unless otherwise specified in wpdb::$field_types.
	 * @return int|false The number of rows affected, or false on error.
	 */
	public function replace( $table, $data, $format = null ) {
		return $this->_insert_replace_helper( $table, $data, $format, 'REPLACE' );
	}

	/**
	 * Helper function for insert and replace.
	 *
	 * Runs an insert or replace query based on $type argument.
	 *
	 * @access private
	 * @since 3.0.0
	 * @see wpdb::prepare()
	 * @see wpdb::$field_types
	 * @see wp_set_wpdb_vars()
	 *
	 * @param string       $table  Table name
	 * @param array        $data   Data to insert (in column => value pairs).
	 *                             Both $data columns and $data values should be "raw" (neither should be SQL escaped).
	 *                             Sending a null value will cause the column to be set to NULL - the corresponding format is ignored in this case.
	 * @param array|string $format Optional. An array of formats to be mapped to each of the value in $data.
	 *                             If string, that format will be used for all of the values in $data.
	 *                             A format is one of '%d', '%f', '%s' (integer, float, string).
	 *                             If omitted, all values in $data will be treated as strings unless otherwise specified in wpdb::$field_types.
	 * @param string $type         Optional. What type of operation is this? INSERT or REPLACE. Defaults to INSERT.
	 * @return int|false The number of rows affected, or false on error.
	 */
	function _insert_replace_helper( $table, $data, $format = null, $type = 'INSERT' ) {
		$this->insert_id = 0;

		if ( ! in_array( strtoupper( $type ), array( 'REPLACE', 'INSERT' ) ) ) {
			return false;
		}

		$data = $this->process_fields( $table, $data, $format );
		if ( false === $data ) {
			return false;
		}

		$formats = $values = array();
		foreach ( $data as $value ) {
			if ( is_null( $value['value'] ) ) {
				$formats[] = 'NULL';
				continue;
			}

			$formats[] = $value['format'];
			$values[]  = $value['value'];
		}

		$fields  = '`' . implode( '`, `', array_keys( $data ) ) . '`';
		$formats = implode( ', ', $formats );

		$sql = "$type INTO `$table` ($fields) VALUES ($formats)";

		$this->check_current_query = false;
		return $this->query( $this->prepare( $sql, $values ) );
	}

	/**
	 * Update a row in the table
	 *
	 *     wpdb::update( 'table', array( 'column' => 'foo', 'field' => 'bar' ), array( 'ID' => 1 ) )
	 *     wpdb::update( 'table', array( 'column' => 'foo', 'field' => 1337 ), array( 'ID' => 1 ), array( '%s', '%d' ), array( '%d' ) )
	 *
	 * @since 2.5.0
	 * @see wpdb::prepare()
	 * @see wpdb::$field_types
	 * @see wp_set_wpdb_vars()
	 *
	 * @param string       $table        Table name
	 * @param array        $data         Data to update (in column => value pairs).
	 *                                   Both $data columns and $data values should be "raw" (neither should be SQL escaped).
	 *                                   Sending a null value will cause the column to be set to NULL - the corresponding
	 *                                   format is ignored in this case.
	 * @param array        $where        A named array of WHERE clauses (in column => value pairs).
	 *                                   Multiple clauses will be joined with ANDs.
	 *                                   Both $where columns and $where values should be "raw".
	 *                                   Sending a null value will create an IS NULL comparison - the corresponding format will be ignored in this case.
	 * @param array|string $format       Optional. An array of formats to be mapped to each of the values in $data.
	 *                                   If string, that format will be used for all of the values in $data.
	 *                                   A format is one of '%d', '%f', '%s' (integer, float, string).
	 *                                   If omitted, all values in $data will be treated as strings unless otherwise specified in wpdb::$field_types.
	 * @param array|string $where_format Optional. An array of formats to be mapped to each of the values in $where.
	 *                                   If string, that format will be used for all of the items in $where.
	 *                                   A format is one of '%d', '%f', '%s' (integer, float, string).
	 *                                   If omitted, all values in $where will be treated as strings.
	 * @return int|false The number of rows updated, or false on error.
	 */
	public function update( $table, $data, $where, $format = null, $where_format = null ) {
		if ( ! is_array( $data ) || ! is_array( $where ) ) {
			return false;
		}

		$data = $this->process_fields( $table, $data, $format );
		if ( false === $data ) {
			return false;
		}
		$where = $this->process_fields( $table, $where, $where_format );
		if ( false === $where ) {
			return false;
		}

		$fields = $conditions = $values = array();
		foreach ( $data as $field => $value ) {
			if ( is_null( $value['value'] ) ) {
				$fields[] = "`$field` = NULL";
				continue;
			}

			$fields[] = "`$field` = " . $value['format'];
			$values[] = $value['value'];
		}
		foreach ( $where as $field => $value ) {
			if ( is_null( $value['value'] ) ) {
				$conditions[] = "`$field` IS NULL";
				continue;
			}

			$conditions[] = "`$field` = " . $value['format'];
			$values[] = $value['value'];
		}

		$fields = implode( ', ', $fields );
		$conditions = implode( ' AND ', $conditions );

		$sql = "UPDATE `$table` SET $fields WHERE $conditions";

		$this->check_current_query = false;
		return $this->query( $this->prepare( $sql, $values ) );
	}

	/**
	 * Delete a row in the table
	 *
	 *     wpdb::delete( 'table', array( 'ID' => 1 ) )
	 *     wpdb::delete( 'table', array( 'ID' => 1 ), array( '%d' ) )
	 *
	 * @since 3.4.0
	 * @see wpdb::prepare()
	 * @see wpdb::$field_types
	 * @see wp_set_wpdb_vars()
	 *
	 * @param string       $table        Table name
	 * @param array        $where        A named array of WHERE clauses (in column => value pairs).
	 *                                   Multiple clauses will be joined with ANDs.
	 *                                   Both $where columns and $where values should be "raw".
	 *                                   Sending a null value will create an IS NULL comparison - the corresponding format will be ignored in this case.
	 * @param array|string $where_format Optional. An array of formats to be mapped to each of the values in $where.
	 *                                   If string, that format will be used for all of the items in $where.
	 *                                   A format is one of '%d', '%f', '%s' (integer, float, string).
	 *                                   If omitted, all values in $where will be treated as strings unless otherwise specified in wpdb::$field_types.
	 * @return int|false The number of rows updated, or false on error.
	 */
	public function delete( $table, $where, $where_format = null ) {
		if ( ! is_array( $where ) ) {
			return false;
		}

		$where = $this->process_fields( $table, $where, $where_format );
		if ( false === $where ) {
			return false;
		}

		$conditions = $values = array();
		foreach ( $where as $field => $value ) {
			if ( is_null( $value['value'] ) ) {
				$conditions[] = "`$field` IS NULL";
				continue;
			}

			$conditions[] = "`$field` = " . $value['format'];
			$values[] = $value['value'];
		}

		$conditions = implode( ' AND ', $conditions );

		$sql = "DELETE FROM `$table` WHERE $conditions";

		$this->check_current_query = false;
		return $this->query( $this->prepare( $sql, $values ) );
	}

	/**
	 * Processes arrays of field/value pairs and field formats.
	 *
	 * This is a helper method for wpdb's CRUD methods, which take field/value
	 * pairs for inserts, updates, and where clauses. This method first pairs
	 * each value with a format. Then it determines the charset of that field,
	 * using that to determine if any invalid text would be stripped. If text is
	 * stripped, then field processing is rejected and the query fails.
	 *
	 * @since 4.2.0
	 * @access protected
	 *
	 * @param string $table  Table name.
	 * @param array  $data   Field/value pair.
	 * @param mixed  $format Format for each field.
	 * @return array|false Returns an array of fields that contain paired values
	 *                    and formats. Returns false for invalid values.
	 */
	protected function process_fields( $table, $data, $format ) {
		$data = $this->process_field_formats( $data, $format );
		if ( false === $data ) {
			return false;
		}

		$converted_data = $this->strip_invalid_text( $data );

		if ( $data !== $converted_data ) {
			return false;
		}

		return $data;
	}

	/**
	 * Prepares arrays of value/format pairs as passed to wpdb CRUD methods.
	 *
	 * @since 4.2.0
	 * @access protected
	 *
	 * @param array $data   Array of fields to values.
	 * @param mixed $format Formats to be mapped to the values in $data.
	 * @return array Array, keyed by field names with values being an array
	 *               of 'value' and 'format' keys.
	 */
	protected function process_field_formats( $data, $format ) {
		$formats = $original_formats = (array) $format;

		foreach ( $data as $field => $value ) {
			$value = array(
				'value'  => $value,
				'format' => '%s',
			);

			if ( ! empty( $format ) ) {
				$value['format'] = array_shift( $formats );
				if ( ! $value['format'] ) {
					$value['format'] = reset( $original_formats );
				}
			} elseif ( isset( $this->field_types[ $field ] ) ) {
				$value['format'] = $this->field_types[ $field ];
			}

			$data[ $field ] = $value;
		}

		return $data;
	}

	/**
	 * Adds field charsets to field/value/format arrays generated by
	 * the wpdb::process_field_formats() method.
	 *
	 * @since 4.2.0
	 * @access protected
	 *
	 * @param array  $data  As it comes from the wpdb::process_field_formats() method.
	 * @param string $table Table name.
	 * @return array|false The same array as $data with additional 'charset' keys.
	 */
	protected function process_field_charsets( $data, $table ) {
		foreach ( $data as $field => $value ) {
			if ( '%d' === $value['format'] || '%f' === $value['format'] ) {
				/*
				 * We can skip this field if we know it isn't a string.
				 * This checks %d/%f versus ! %s because its sprintf() could take more.
				 */
				$value['charset'] = false;
			} else {
				$value['charset'] = $this->get_col_charset( $table, $field );
				if ( is_wp_error( $value['charset'] ) ) {
					return false;
				}
			}

			$data[ $field ] = $value;
		}

		return $data;
	}

	/**
	 * For string fields, record the maximum string length that field can safely save.
	 *
	 * @since 4.2.1
	 * @access protected
	 *
	 * @param array  $data  As it comes from the wpdb::process_field_charsets() method.
	 * @param string $table Table name.
	 * @return array|false The same array as $data with additional 'length' keys, or false if
	 *                     any of the values were too long for their corresponding field.
	 */
	protected function process_field_lengths( $data, $table ) {
		foreach ( $data as $field => $value ) {
			if ( '%d' === $value['format'] || '%f' === $value['format'] ) {
				/*
				 * We can skip this field if we know it isn't a string.
				 * This checks %d/%f versus ! %s because its sprintf() could take more.
				 */
				$value['length'] = false;
			} else {
				$value['length'] = $this->get_col_length( $table, $field );
				if ( is_wp_error( $value['length'] ) ) {
					return false;
				}
			}

			$data[ $field ] = $value;
		}

		return $data;
	}

	/**
	 * Retrieve one variable from the database.
	 *
	 * Executes a SQL query and returns the value from the SQL result.
	 * If the SQL result contains more than one column and/or more than one row, this function returns the value in the column and row specified.
	 * If $query is null, this function returns the value in the specified column and row from the previous SQL result.
	 *
	 * @since 0.71
	 *
	 * @param string|null $query Optional. SQL query. Defaults to null, use the result from the previous query.
	 * @param int         $x     Optional. Column of value to return. Indexed from 0.
	 * @param int         $y     Optional. Row of value to return. Indexed from 0.
	 * @return string|null Database query result (as string), or null on failure
	 */
	public function get_var( $query = null, $x = 0, $y = 0 ) {
		$this->func_call = "\$db->get_var(\"$query\", $x, $y)";

		if ( $query ) {
			$this->query( $query );
		}

		// Extract var out of cached results based x,y vals
		if ( ! empty( $this->last_result[$y] ) ) {
			$values = array_values( $this->last_result[$y] );
		}

		// If there is a value return it else return null
		return ( isset( $values[$x] ) && $values[$x] !== '' ) ? $values[$x] : null;
	}

	/**
	 * Retrieve one row from the database.
	 *
	 * Executes a SQL query and returns the row from the SQL result.
	 *
	 * @since 0.71
	 *
	 * @param string|null $query  SQL query.
	 * @param string      $output Optional. one of ARRAY_A | ARRAY_N | OBJECT constants.
	 *                            Return an associative array (column => value, ...),
	 *                            a numerically indexed array (0 => value, ...) or
	 *                            an object ( ->column = value ), respectively.
	 * @param int         $y      Optional. Row to return. Indexed from 0.
	 * @return array|object|null|void Database query result in format specified by $output or null on failure
	 */
	public function get_row( $query = null, $output = ARRAY_A, $y = 0 ) {
		$this->func_call = "\$db->get_row(\"$query\",$output,$y)";

		if ( $query ) {
			$this->query( $query );
		} else {
			return null;
		}

		if ( !isset( $this->last_result[$y] ) )
			return null;

		if ( $output == ARRAY_A ) {
			return $this->last_result[$y] ? $this->last_result[$y] : null;
		} elseif ( $output == ARRAY_N ) {
			return $this->last_result[$y] ? array_values( $this->last_result[$y] ) : null;
		} else {
			$this->print_error( " \$db->get_row(string query, output type, int offset) -- Output type must be one of: ARRAY_A, ARRAY_N" );
		}
	}

	/**
	 * Retrieve one column from the database.
	 *
	 * Executes a SQL query and returns the column from the SQL result.
	 * If the SQL result contains more than one column, this function returns the column specified.
	 * If $query is null, this function returns the specified column from the previous SQL result.
	 *
	 * @since 0.71
	 *
	 * @param string|null $query Optional. SQL query. Defaults to previous query.
	 * @param int         $x     Optional. Column to return. Indexed from 0.
	 * @return array Database query result. Array indexed from 0 by SQL result row number.
	 */
	public function get_col( $query = null , $x = 0 ) {

		if ( $query ) {
			$this->query( $query );
		}

		$new_array = array();
		// Extract the column values
		for ( $i = 0, $j = count( $this->last_result ); $i < $j; $i++ ) {
			$new_array[$i] = $this->get_var( null, $x, $i );
		}
		return $new_array;
	}

	/**
	 * Retrieve an entire SQL result set from the database (i.e., many rows)
	 *
	 * Executes a SQL query and returns the entire SQL result.
	 *
	 * @since 0.71
	 *
	 * @param string $query  SQL query.
	 * @param string $output Optional. Any of ARRAY_A | ARRAY_N | OBJECT | OBJECT_K constants.
	 *                       With one of the first three, return an array of rows indexed from 0 by SQL result row number.
	 *                       Each row is an associative array (column => value, ...), a numerically indexed array (0 => value, ...), or an object. ( ->column = value ), respectively.
	 *                       With OBJECT_K, return an associative array of row objects keyed by the value of each row's first column's value.
	 *                       Duplicate keys are discarded.
	 * @return array|object|null Database query results
	 */
	public function get_results( $query = null, $output = ARRAY_A ) {
		$this->func_call = "\$db->get_results(\"$query\", $output)";

		if ( $query ) {
			$this->query( $query );
		} else {
			return null;
		}

		$new_array = array();
		if ( $this->last_result ) {
			if ( $output == ARRAY_A ) {
				return $this->last_result;
			} elseif ( $output == ARRAY_N ) {
				// Return an integer-keyed array of...
				foreach ( (array) $this->last_result as $row ) {
					// ...integer-keyed row arrays
					$new_array[] = array_values( $row );
				}
			}
			return $new_array;
		}
		return null;
	}

	/**
	 * Retrieves the character set for the given table.
	 *
	 * @since 4.2.0
	 * @access protected
	 *
	 * @param string $table Table name.
	 * @return string|WP_Error Table character set, WP_Error object if it couldn't be found.
	 */
	protected function get_table_charset( $table ) {
		return 'utf8';
		$tablekey = strtolower( $table );

		$charset = null;

		if ( isset( $this->table_charset[ $tablekey ] ) ) {
			return $this->table_charset[ $tablekey ];
		}

		$charsets = $columns = array();

		$table_parts = explode( '.', $table );
		$table = '`' . implode( '`.`', $table_parts ) . '`';
		$results = $this->get_results( "SHOW FULL COLUMNS FROM $table" );
		if ( ! $results ) {
			return new WP_Error( 'wpdb_get_table_charset_failure' );
		}

		foreach ( $results as $column ) {
			$columns[ strtolower( $column->Field ) ] = $column;
		}

		$this->col_meta[ $tablekey ] = $columns;

		foreach ( $columns as $column ) {
			if ( ! empty( $column->Collation ) ) {
				list( $charset ) = explode( '_', $column->Collation );

				// If the current connection can't support utf8mb4 characters, let's only send 3-byte utf8 characters.
				if ( 'utf8mb4' === $charset && ! $this->has_cap( 'utf8mb4' ) ) {
					$charset = 'utf8';
				}

				$charsets[ strtolower( $charset ) ] = true;
			}

			list( $type ) = explode( '(', $column->Type );

			// A binary/blob means the whole query gets treated like this.
			if ( in_array( strtoupper( $type ), array( 'BINARY', 'VARBINARY', 'TINYBLOB', 'MEDIUMBLOB', 'BLOB', 'LONGBLOB' ) ) ) {
				$this->table_charset[ $tablekey ] = 'binary';
				return 'binary';
			}
		}

		// utf8mb3 is an alias for utf8.
		if ( isset( $charsets['utf8mb3'] ) ) {
			$charsets['utf8'] = true;
			unset( $charsets['utf8mb3'] );
		}

		// Check if we have more than one charset in play.
		$count = count( $charsets );
		if ( 1 === $count ) {
			$charset = key( $charsets );
		} elseif ( 0 === $count ) {
			// No charsets, assume this table can store whatever.
			$charset = false;
		} else {
			// More than one charset. Remove latin1 if present and recalculate.
			unset( $charsets['latin1'] );
			$count = count( $charsets );
			if ( 1 === $count ) {
				// Only one charset (besides latin1).
				$charset = key( $charsets );
			} elseif ( 2 === $count && isset( $charsets['utf8'], $charsets['utf8mb4'] ) ) {
				// Two charsets, but they're utf8 and utf8mb4, use utf8.
				$charset = 'utf8';
			} else {
				// Two mixed character sets. ascii.
				$charset = 'ascii';
			}
		}

		$this->table_charset[ $tablekey ] = $charset;
		return $charset;
	}

	/**
	 * Retrieves the character set for the given column.
	 *
	 * @since 4.2.0
	 * @access public
	 *
	 * @param string $table  Table name.
	 * @param string $column Column name.
	 * @return string|false|WP_Error Column character set as a string. False if the column has no
	 *                               character set. WP_Error object if there was an error.
	 */
	public function get_col_charset( $table, $column ) {
		return 'utf8';
		$tablekey = strtolower( $table );
		$columnkey = strtolower( $column );

		$charset = null;

		// Skip this entirely if this isn't a MySQL database.
		if ( empty( $this->is_mysql ) ) {
			return false;
		}

		if ( empty( $this->table_charset[ $tablekey ] ) ) {
			// This primes column information for us.
			$table_charset = $this->get_table_charset( $table );
			if ( is_wp_error( $table_charset ) ) {
				return $table_charset;
			}
		}

		// If still no column information, return the table charset.
		if ( empty( $this->col_meta[ $tablekey ] ) ) {
			return $this->table_charset[ $tablekey ];
		}

		// If this column doesn't exist, return the table charset.
		if ( empty( $this->col_meta[ $tablekey ][ $columnkey ] ) ) {
			return $this->table_charset[ $tablekey ];
		}

		// Return false when it's not a string column.
		if ( empty( $this->col_meta[ $tablekey ][ $columnkey ]->Collation ) ) {
			return false;
		}

		list( $charset ) = explode( '_', $this->col_meta[ $tablekey ][ $columnkey ]->Collation );
		return $charset;
	}

	/**
	 * Retrieve the maximum string length allowed in a given column.
	 * The length may either be specified as a byte length or a character length.
	 *
	 * @since 4.2.1
	 * @access public
	 *
	 * @param string $table  Table name.
	 * @param string $column Column name.
	 * @return array|false|WP_Error array( 'length' => (int), 'type' => 'byte' | 'char' )
	 *                              false if the column has no length (for example, numeric column)
	 *                              WP_Error object if there was an error.
	 */
	public function get_col_length( $table, $column ) {
		$tablekey = strtolower( $table );
		$columnkey = strtolower( $column );

		// Skip this entirely if this isn't a MySQL database.
		if ( empty( $this->is_mysql ) ) {
			return false;
		}

		if ( empty( $this->col_meta[ $tablekey ] ) ) {
			// This primes column information for us.
			$table_charset = $this->get_table_charset( $table );
			if ( is_wp_error( $table_charset ) ) {
				return $table_charset;
			}
		}

		if ( empty( $this->col_meta[ $tablekey ][ $columnkey ] ) ) {
			return false;
		}

		$typeinfo = explode( '(', $this->col_meta[ $tablekey ][ $columnkey ]->Type );

		$type = strtolower( $typeinfo[0] );
		if ( ! empty( $typeinfo[1] ) ) {
			$length = trim( $typeinfo[1], ')' );
		} else {
			$length = false;
		}

		switch( $type ) {
			case 'char':
			case 'varchar':
				return array(
					'type'   => 'char',
					'length' => (int) $length,
				);

			case 'binary':
			case 'varbinary':
				return array(
					'type'   => 'byte',
					'length' => (int) $length,
				);

			case 'tinyblob':
			case 'tinytext':
				return array(
					'type'   => 'byte',
					'length' => 255,        // 2^8 - 1
				);

			case 'blob':
			case 'text':
				return array(
					'type'   => 'byte',
					'length' => 65535,      // 2^16 - 1
				);

			case 'mediumblob':
			case 'mediumtext':
				return array(
					'type'   => 'byte',
					'length' => 16777215,   // 2^24 - 1
				);

			case 'longblob':
			case 'longtext':
				return array(
					'type'   => 'byte',
					'length' => 4294967295, // 2^32 - 1
				);

			default:
				return false;
		}
	}

	/**
	 * Check if a string is ASCII.
	 *
	 * The negative regex is faster for non-ASCII strings, as it allows
	 * the search to finish as soon as it encounters a non-ASCII character.
	 *
	 * @since 4.2.0
	 * @access protected
	 *
	 * @param string $string String to check.
	 * @return bool True if ASCII, false if not.
	 */
	protected function check_ascii( $string ) {
		if ( function_exists( 'mb_check_encoding' ) ) {
			if ( mb_check_encoding( $string, 'ASCII' ) ) {
				return true;
			}
		} elseif ( ! preg_match( '/[^\x00-\x7F]/', $string ) ) {
			return true;
		}

		return false;
	}

	/**
	 * Strips any invalid characters based on value/charset pairs.
	 *
	 * @since 4.2.0
	 * @access protected
	 *
	 * @param array $data Array of value arrays. Each value array has the keys
	 *                    'value' and 'charset'. An optional 'ascii' key can be
	 *                    set to false to avoid redundant ASCII checks.
	 * @return array|WP_Error The $data parameter, with invalid characters removed from
	 *                        each value. This works as a passthrough: any additional keys
	 *                        such as 'field' are retained in each value array. If we cannot
	 *                        remove invalid characters, a WP_Error object is returned.
	 */
	protected function strip_invalid_text( $data ) {
		$db_check_string = false;

		foreach ( $data as &$value ) {
			$charset = 'utf8';

			if ( isset( $value['length'] ) && is_array( $value['length'] ) ) {
				$length = $value['length']['length'];
				$truncate_by_byte_length = 'byte' === $value['length']['type'];
			} else {
				$length = false;
				// Since we have no length, we'll never truncate.
				// Initialize the variable to false. true would take us
				// through an unnecessary (for this case) codepath below.
				$truncate_by_byte_length = false;
			}

			// There's no charset to work with.
			if ( false === $charset ) {
				continue;
			}

			// Column isn't a string.
			if ( ! is_string( $value['value'] ) ) {
				continue;
			}

			$needs_validation = true;
			if (
				// latin1 can store any byte sequence
				'latin1' === $charset
			||
				// ASCII is always OK.
				( ! isset( $value['ascii'] ) && $this->check_ascii( $value['value'] ) )
			) {
				$truncate_by_byte_length = true;
				$needs_validation = false;
			}

			if ( $truncate_by_byte_length ) {
				mbstring_binary_safe_encoding();
				if ( false !== $length && strlen( $value['value'] ) > $length ) {
					$value['value'] = substr( $value['value'], 0, $length );
				}
				reset_mbstring_encoding();

				if ( ! $needs_validation ) {
					continue;
				}
			}

			// utf8 can be handled by regex, which is a bunch faster than a DB lookup.
			if ( ( 'utf8' === $charset || 'utf8mb3' === $charset || 'utf8mb4' === $charset ) && function_exists( 'mb_strlen' ) ) {
				$regex = '/
					(
						(?: [\x00-\x7F]                  # single-byte sequences   0xxxxxxx
						|   [\xC2-\xDF][\x80-\xBF]       # double-byte sequences   110xxxxx 10xxxxxx
						|   \xE0[\xA0-\xBF][\x80-\xBF]   # triple-byte sequences   1110xxxx 10xxxxxx * 2
						|   [\xE1-\xEC][\x80-\xBF]{2}
						|   \xED[\x80-\x9F][\x80-\xBF]
						|   [\xEE-\xEF][\x80-\xBF]{2}';

				if ( 'utf8mb4' === $charset ) {
					$regex .= '
						|    \xF0[\x90-\xBF][\x80-\xBF]{2} # four-byte sequences   11110xxx 10xxxxxx * 3
						|    [\xF1-\xF3][\x80-\xBF]{3}
						|    \xF4[\x80-\x8F][\x80-\xBF]{2}
					';
				}

				$regex .= '){1,40}                          # ...one or more times
					)
					| .                                  # anything else
					/x';
				$value['value'] = preg_replace( $regex, '$1', $value['value'] );


				if ( false !== $length && mb_strlen( $value['value'], 'UTF-8' ) > $length ) {
					$value['value'] = mb_substr( $value['value'], 0, $length, 'UTF-8' );
				}
				continue;
			}

			// We couldn't use any local conversions, send it to the DB.
			$value['db'] = $db_check_string = true;
		}
		unset( $value ); // Remove by reference.

		return $data;
	}

	/**
	 * Starts the timer, for debugging purposes.
	 *
	 * @since 1.5.0
	 *
	 * @return true
	 */
	public function timer_start() {
		$this->time_start = microtime( true );
		return true;
	}

	/**
	 * Stops the debugging timer.
	 *
	 * @since 1.5.0
	 *
	 * @return float Total time spent on the query, in seconds
	 */
	public function timer_stop() {
		return ( microtime( true ) - $this->time_start );
	}

	/**
	 * Wraps errors in a nice header and footer and dies.
	 *
	 * Will not die if wpdb::$show_errors is false.
	 *
	 * @since 1.5.0
	 *
	 * @param string $message    The Error message
	 * @param string $error_code Optional. A Computer readable string to identify the error.
	 * @return false|void
	 */
	public function bail( $message, $error_code = '500' ) {
		if ( ! $this->show_errors ) {
			if ( class_exists( 'WP_Error', false ) ) {
				$this->error = new WP_Error($error_code, $message);
			} else {
				$this->error = $message;
			}
			return false;
		}
		wp_die($message);
	}


	/**
	 * Closes the current database connection.
	 *
	 * @since 4.5.0
	 * @access public
	 *
	 * @return bool True if the connection was successfully closed, false if it wasn't,
	 *              or the connection doesn't exist.
	 */
	public function close() {
		if ( ! $this->dbh ) {
			return false;
		}

		$closed = $this->dbh->close();

		if ( $closed ) {
			$this->dbh = null;
			$this->ready = false;
			$this->has_connected = false;
		}

		return $closed;
	}
}