sqlite-database-integration / wp-includes / sqlite / class-wp-sqlite-db.php

class-wp-sqlite-db.php in SQLite Database Integration 3.0.2, at wp-includes/sqlite/class-wp-sqlite-db.php

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1	<?php
2	/**
3	* Extend and replace the wpdb class.
4	*/
5
6	/**
7	* This class extends wpdb and replaces it.
8	*
9	* It also rewrites some methods that use mysql specific functions.
10	*/
11	class WP_SQLite_DB extends wpdb {
12
13	/**
14	* Database Handle
15	*
16	* @var WP_MySQL_On_SQLite
17	*/
18	protected $dbh;
19
20	/**
21	* Backward compatibility, see wpdb::$allow_unsafe_unquoted_parameters.
22	*
23	* This property is mirroring "wpdb::$allow_unsafe_unquoted_parameters",
24	* because some tests are accessing it externally using PHP reflection.
25	*
26	* @var
27	*/
28	private $allow_unsafe_unquoted_parameters = true;
29
30	/**
31	* Connects to the SQLite database.
32	*
33	* Unlike for MySQL, no credentials and host are needed.
34	*
35	* @param string $dbname Database name.
36	*/
37	public function __construct( $dbname ) {
38	/**
39	* We need to initialize the "$wpdb" global early, so that the SQLite
40	* driver can configure the database. The call stack goes like this:
41	*
42	* 1. The "parent::__construct()" call executes "$this->db_connect()".
43	* 2. The database connection call initializes the SQLite driver.
44	* 3. The SQLite driver initializes and runs "WP_SQLite_Configurator".
45	* 4. The configurator uses "WP_SQLite_Information_Schema_Reconstructor",
46	* which requires "wp-admin/includes/schema.php" when in WordPress.
47	* 5. The "wp-admin/includes/schema.php" requires the "$wpdb" global,
48	* which creates a circular dependency.
49	*/
50	$GLOBALS['wpdb'] = $this;
51
52	parent::__construct( '', '', $dbname, '' );
53	$this->charset = 'utf8mb4';
54	}
55
56	/**
57	* Returns the active MySQL-on-SQLite driver.
58	*
59	* @return WP_MySQL_On_SQLite The active driver.
60	* @throws RuntimeException When there is no active database connection.
61	*/
62	public function get_driver(): WP_MySQL_On_SQLite {
63	if ( ! $this->dbh ) {
64	throw new RuntimeException( 'Cannot access the driver without an active database connection.' );
65	}
66
67	return $this->dbh;
68	}
69
70	/**
71	* Method to set character set for the database.
72	*
73	* This overrides wpdb::set_charset(), only to dummy out the MySQL function.
74	*
75	* @see wpdb::set_charset()
76	*
77	* @param resource $dbh The resource given by mysql_connect.
78	* @param string $charset Optional. The character set. Default null.
79	* @param string $collate Optional. The collation. Default null.
80	*/
81	public function set_charset( $dbh, $charset = null, $collate = null ) {
82	}
83
84	/**
85	* Retrieves the character set for the given column.
86	*
87	* This overrides wpdb::get_col_charset() to enable the parent's implementation
88	* for SQLite by temporarily setting the is_mysql flag.
89	*
90	* @see wpdb::get_col_charset()
91	*
92	* @param string $table Table name.
93	* @param string $column Column name.
94	* @return string\|false\|WP_Error Column character set as a string. False if the column has
95	* no character set. WP_Error object on failure.
96	*/
97	public function get_col_charset( $table, $column ) {
98	$original_is_mysql = $this->is_mysql ?? null;
99
100	/*
101	* The parent method returns early when `$this->is_mysql` is falsy.
102	* Since SQLite doesn't set this flag, we enable it temporarily so
103	* the parent can run its full logic — querying column metadata via
104	* SHOW FULL COLUMNS (which the SQLite driver translates) and
105	* populating the `$this->col_meta` cache.
106	*/
107	try {
108	$this->is_mysql = true;
109	return parent::get_col_charset( $table, $column );
110	} finally {
111	$this->is_mysql = $original_is_mysql;
112	}
113	}
114
115	/**
116	* Retrieves the maximum string length allowed in a given column.
117	*
118	* This overrides wpdb::get_col_length() to enable the parent's implementation
119	* for SQLite by temporarily setting the is_mysql flag.
120	*
121	* @see wpdb::get_col_length()
122	*
123	* @param string $table Table name.
124	* @param string $column Column name.
125	* @return array\|false\|WP_Error Column length information, false if the column has
126	* no length. WP_Error object on failure.
127	*/
128	public function get_col_length( $table, $column ) {
129	$original_is_mysql = $this->is_mysql ?? null;
130
131	// See get_col_charset() for an explanation of the is_mysql flag.
132	try {
133	$this->is_mysql = true;
134	return parent::get_col_length( $table, $column );
135	} finally {
136	$this->is_mysql = $original_is_mysql;
137	}
138	}
139
140	/**
141	* Changes the current SQL mode, and ensures its WordPress compatibility.
142	*
143	* If no modes are passed, it will ensure the current MySQL server modes are compatible.
144	*
145	* This overrides wpdb::set_sql_mode() while closely mirroring its implementation.
146	*
147	* @param array $modes Optional. A list of SQL modes to set. Default empty array.
148	*/
149	public function set_sql_mode( $modes = array() ) {
150	if ( empty( $modes ) ) {
151	$result = $this->dbh->query( 'SELECT @@SESSION.sql_mode' )->fetchAll( PDO::FETCH_OBJ ); // phpcs:ignore WordPress.DB.RestrictedClasses.mysql__PDO
152	if ( ! isset( $result[0] ) ) {
153	return;
154	}
155
156	$modes_str = $result[0]->{'@@SESSION.sql_mode'};
157	if ( empty( $modes_str ) ) {
158	return;
159	}
160	$modes = explode( ',', $modes_str );
161	}
162
163	$modes = array_change_key_case( $modes, CASE_UPPER );
164
165	/**
166	* Filters the list of incompatible SQL modes to exclude.
167	*
168	* @since 3.9.0
169	*
170	* @param array $incompatible_modes An array of incompatible modes.
171	*/
172	$incompatible_modes = (array) apply_filters( 'incompatible_sql_modes', $this->incompatible_modes );
173
174	foreach ( $modes as $i => $mode ) {
175	if ( in_array( $mode, $incompatible_modes, true ) ) {
176	unset( $modes[ $i ] );
177	}
178	}
179	$modes_str = implode( ',', $modes );
180
181	$this->dbh->query( "SET SESSION sql_mode='$modes_str'" );
182	}
183
184	/**
185	* Closes the current database connection.
186	*
187	* This overrides wpdb::close() while closely mirroring its implementation.
188	*
189	* @see wpdb::close()
190	*
191	* @return bool True if the connection was successfully closed,
192	* false if it wasn't, or if the connection doesn't exist.
193	*/
194	public function close() {
195	if ( ! $this->dbh ) {
196	return false;
197	}
198
199	$connection = $this->dbh->get_connection();
200	$pdo = $connection->get_pdo();
201
202	try {
203	if ( $this->dbh->inTransaction() ) {
204	$this->dbh->rollBack();
205	} elseif ( $pdo->inTransaction() ) {
206	$pdo->rollBack();
207	} else {
208	/*
209	* On PHP < 8.4, PDO cannot detect transactions started via SQL.
210	* A savepoint ensures ROLLBACK succeeds with or without one.
211	*/
212	$pdo->exec( 'SAVEPOINT wp_sqlite_db_close' );
213	$pdo->exec( 'ROLLBACK' );
214	}
215	} catch ( Throwable $e ) {
216	return false;
217	}
218
219	if (
220	isset( $GLOBALS['@pdo'] )
221	&& $GLOBALS['@pdo'] === $pdo
222	) {
223	unset( $GLOBALS['@pdo'] );
224	}
225
226	$connection->set_query_logger( null );
227	$this->result = null;
228	$this->dbh = null;
229	$this->ready = false;
230	$this->has_connected = false;
231
232	return true;
233	}
234
235	/**
236	* Determines the best charset and collation to use given a charset and collation.
237	*
238	* For example, when able, utf8mb4 should be used instead of utf8.
239	*
240	* This overrides wpdb::determine_charset() while closely mirroring its implementation.
241	* The override is needed because the parent checks for a mysqli connection object.
242	*
243	* @param string $charset The character set to check.
244	* @param string $collate The collation to check.
245	* @return array {
246	* The most appropriate character set and collation to use.
247	*
248	* @type string $charset Character set.
249	* @type string $collate Collation.
250	* }
251	*/
252	public function determine_charset( $charset, $collate ) {
253	if ( ! $this->dbh ) {
254	return compact( 'charset', 'collate' );
255	}
256
257	if ( 'utf8' === $charset ) {
258	$charset = 'utf8mb4';
259	}
260
261	if ( 'utf8mb4' === $charset ) {
262	// _general_ is outdated, so we can upgrade it to _unicode_, instead.
263	if ( ! $collate \|\| 'utf8_general_ci' === $collate ) {
264	$collate = 'utf8mb4_unicode_ci';
265	} else {
266	$collate = str_replace( 'utf8_', 'utf8mb4_', $collate );
267	}
268	}
269
270	// _unicode_520_ is a better collation, we should use that when it's available.
271	if ( $this->has_cap( 'utf8mb4_520' ) && 'utf8mb4_unicode_ci' === $collate ) {
272	$collate = 'utf8mb4_unicode_520_ci';
273	}
274
275	return compact( 'charset', 'collate' );
276	}
277
278	/**
279	* Method to select the database connection.
280	*
281	* This overrides wpdb::select(), only to dummy out the MySQL function.
282	*
283	* @see wpdb::select()
284	*
285	* @param string $db MySQL database name. Not used.
286	* @param resource\|null $dbh Optional link identifier.
287	*/
288	public function select( $db, $dbh = null ) {
289	$this->ready = true;
290	}
291
292	/**
293	* Method to escape characters.
294	*
295	* This overrides wpdb::_real_escape() to avoid using mysql_real_escape_string().
296	*
297	* @see wpdb::_real_escape()
298	*
299	* @param string $data The string to escape.
300	*
301	* @return string escaped
302	* @throws RuntimeException When the database connection is not initialized.
303	*/
304	public function _real_escape( $data ) {
305	if ( ! is_scalar( $data ) ) {
306	return '';
307	}
308
309	if ( ! $this->dbh ) {
310	throw new RuntimeException( 'Cannot escape data without an active database connection.' );
311	}
312
313	// Escape the string without bounding quotes to mirror mysqli_real_escape_string().
314	$quoted = $this->dbh->quote( (string) $data );
315	$escaped = substr( $quoted, 1, -1 );
316	return $this->add_placeholder_escape( $escaped );
317	}
318
319	/**
320	* Prints SQL/DB error.
321	*
322	* This overrides wpdb::print_error() while closely mirroring its implementation.
323	*
324	* @global array $EZSQL_ERROR Stores error information of query and error string.
325	*
326	* @param string $str The error to display.
327	* @return void\|false Void if the showing of errors is enabled, false if disabled.
328	*/
329	public function print_error( $str = '' ) {
330	global $EZSQL_ERROR;
331
332	if ( ! $str ) {
333	$str = $this->last_error;
334	}
335
336	$EZSQL_ERROR[] = array(
337	'query' => $this->last_query,
338	'error_str' => $str,
339	);
340
341	if ( $this->suppress_errors ) {
342	return false;
343	}
344
345	$caller = $this->get_caller();
346	if ( $caller ) {
347	// Not translated, as this will only appear in the error log.
348	$error_str = sprintf( 'WordPress database error %1$s for query %2$s made by %3$s', $str, $this->last_query, $caller );
349	} else {
350	$error_str = sprintf( 'WordPress database error %1$s for query %2$s', $str, $this->last_query );
351	}
352
353	error_log( $error_str );
354
355	// Are we showing errors?
356	if ( ! $this->show_errors ) {
357	return false;
358	}
359
360	wp_load_translations_early();
361
362	// If there is an error then take note of it.
363	if ( is_multisite() ) {
364	$msg = sprintf(
365	"%s [%s]\n%s\n",
366	__( 'WordPress database error:' ),
367	$str,
368	$this->last_query
369	);
370
371	if ( defined( 'ERRORLOGFILE' ) ) {
372	error_log( $msg, 3, ERRORLOGFILE );
373	}
374	if ( defined( 'DIEONDBERROR' ) ) {
375	wp_die( $msg );
376	}
377	} else {
378	$str = htmlspecialchars( $str, ENT_QUOTES );
379	$query = htmlspecialchars( $this->last_query, ENT_QUOTES );
380
381	printf(
382	'<div id="error"><p class="wpdberror"><strong>%s</strong> [%s]<br /><code>%s</code></p></div>',
383	__( 'WordPress database error:' ),
384	$str,
385	$query
386	);
387	}
388	}
389
390	/**
391	* Method to flush cached data.
392	*
393	* This overrides wpdb::flush(). This is not necessarily overridden, because
394	* $result will never be resource.
395	*
396	* @see wpdb::flush
397	*/
398	public function flush() {
399	$this->last_result = array();
400	$this->col_info = null;
401	$this->last_query = null;
402	$this->rows_affected = 0;
403	$this->num_rows = 0;
404	$this->last_error = '';
405	$this->result = null;
406	}
407
408	/**
409	* Method to do the database connection.
410	*
411	* This overrides wpdb::db_connect() to avoid using MySQL function.
412	*
413	* @see wpdb::db_connect()
414	*
415	* @param bool $allow_bail Not used.
416	* @return bool True on a successful connection, false on failure.
417	*/
418	public function db_connect( $allow_bail = true ) {
419	if ( $this->dbh ) {
420	return $this->ready;
421	}
422
423	$this->last_error = '';
424	if ( isset( $GLOBALS['@pdo'] ) ) {
425	trigger_error(
426	'PDO injection via $GLOBALS[\'@pdo\'] is no longer supported. The existing PDO will be ignored and a new connection will be created.',
427	E_USER_WARNING
428	);
429	}
430
431	if ( ! isset( $this->charset ) ) {
432	$this->init_charset();
433	}
434
435	// Migrate the database file from a legacy path, if it exists.
436	if ( ! defined( 'DB_FILE' ) && ! file_exists( FQDB ) ) {
437	$old_db_path = FQDBDIR . '.ht.sqlite.php';
438
439	if ( file_exists( $old_db_path ) ) {
440	if ( ! rename( $old_db_path, FQDB ) ) {
441	wp_die( 'Failed to rename database file.', 'Error!' );
442	}
443
444	foreach ( array( '-wal', '-shm', '-journal' ) as $suffix ) {
445	if ( file_exists( $old_db_path . $suffix ) ) {
446	if ( ! rename( $old_db_path . $suffix, FQDB . $suffix ) ) {
447	wp_die( 'Failed to rename database file.', 'Error!' );
448	}
449	}
450	}
451	}
452	}
453
454	if ( null === $this->dbname \|\| '' === $this->dbname ) {
455	$this->bail(
456	'The database name was not set. The SQLite driver requires a database name to be set to emulate MySQL information schema tables.',
457	'db_connect_fail'
458	);
459	return false;
460	}
461
462	$this->ensure_database_directory( FQDB );
463
464	try {
465	$options = array(
466	'sqlite_journal_mode' => defined( 'SQLITE_JOURNAL_MODE' ) ? SQLITE_JOURNAL_MODE : null,
467	);
468	$dbh = new WP_MySQL_On_SQLite(
469	sprintf(
470	'mysql-on-sqlite:path=%s;dbname=%s',
471	str_replace( ';', ';;', FQDB ),
472	str_replace( ';', ';;', $this->dbname )
473	),
474	null,
475	null,
476	$options
477	);
478	$dbh->setAttribute( PDO::ATTR_STRINGIFY_FETCHES, true ); // phpcs:ignore WordPress.DB.RestrictedClasses.mysql__PDO
479	$this->dbh = $dbh;
480
481	/**
482	* Exposes the underlying PDO SQLite connection for backward compatibility.
483	*
484	* @deprecated 3.0.0 Use WP_SQLite_DB::get_driver() with
485	* WP_MySQL_On_SQLite::get_sqlite_pdo() instead.
486	*/
487	$GLOBALS['@pdo'] = $dbh->get_sqlite_pdo();
488	} catch ( Throwable $e ) {
489	$this->last_error = $this->format_error_message( $e );
490	}
491	if ( $this->last_error ) {
492	return false;
493	}
494
495	$this->has_connected = true;
496	$this->set_charset( $this->dbh );
497
498	$this->ready = true;
499	$this->set_sql_mode();
500	return true;
501	}
502
503	/**
504	* Checks that the database connection is available.
505	*
506	* @param bool $allow_bail Not used.
507	*
508	* @return bool True when the connection is available, false otherwise.
509	*/
510	public function check_connection( $allow_bail = true ) {
511	if ( $this->dbh ) {
512	return true;
513	}
514
515	return $this->db_connect( $allow_bail );
516	}
517
518	/**
519	* Prepares a SQL query for safe execution.
520	*
521	* See "wpdb::prepare()". This override only fixes a WPDB test issue.
522	*
523	* @param string $query Query statement with `sprintf()`-like placeholders.
524	* @param array\|mixed $args The array of variables or the first variable to substitute.
525	* @param mixed ...$args Further variables to substitute when using individual arguments.
526	* @return string\|void Sanitized query string, if there is a query to prepare.
527	*/
528	public function prepare( $query, ...$args ) {
529	/*
530	* Sync "$allow_unsafe_unquoted_parameters" with the WPDB parent property.
531	* This is only needed because some WPDB tests are accessing the private
532	* property externally via PHP reflection. This should be fixed WP tests.
533	*/
534	$wpdb_allow_unsafe_unquoted_parameters = $this->__get( 'allow_unsafe_unquoted_parameters' );
535	if ( $wpdb_allow_unsafe_unquoted_parameters !== $this->allow_unsafe_unquoted_parameters ) {
536	$property = new ReflectionProperty( 'wpdb', 'allow_unsafe_unquoted_parameters' );
537	$property->setAccessible( true );
538	$property->setValue( $this, $this->allow_unsafe_unquoted_parameters );
539	$property->setAccessible( false );
540	}
541
542	return parent::prepare( $query, ...$args );
543	}
544
545	/**
546	* Performs a database query.
547	*
548	* This overrides wpdb::query() while closely mirroring its implementation.
549	*
550	* @see wpdb::query()
551	*
552	* @param string $query Database query.
553	*
554	* @param string $query Database query.
555	* @return int\|bool Boolean true for CREATE, ALTER, TRUNCATE and DROP queries. Number of rows
556	* affected/selected for all other queries. Boolean false on error.
557	*/
558	public function query( $query ) {
559	// Query Monitor integration:
560	$query_monitor_active = defined( 'SQLITE_QUERY_MONITOR_LOADED' ) && SQLITE_QUERY_MONITOR_LOADED;
561	if ( $query_monitor_active && $this->show_errors ) {
562	$this->hide_errors();
563	}
564
565	if ( ! $this->ready ) {
566	$this->check_current_query = true;
567	return false;
568	}
569
570	$query = apply_filters( 'query', $query );
571
572	if ( ! $query ) {
573	$this->insert_id = 0;
574	return false;
575	}
576
577	$this->flush();
578
579	// Log how the function was called.
580	$this->func_call = "\$db->query(\"$query\")";
581
582	/*
583	* Mirror wpdb's query text validation.
584	* TODO: Add full charset enforcement to MySQL on SQLite, where column
585	* types and SQL mode are known, so all callers are protected.
586	*/
587	if ( $this->check_current_query && ! $this->check_ascii( $query ) ) {
588	$stripped_query = $this->strip_invalid_text_from_query( $query );
589	// Charset discovery can run queries, so clear their results.
590	$this->flush();
591	if ( $stripped_query !== $query ) {
592	$this->insert_id = 0;
593	$this->last_query = $query;
594	wp_load_translations_early();
595	$this->last_error = __( 'WordPress database error: Could not perform query because it contains invalid data.' );
596	return false;
597	}
598	}
599	$this->check_current_query = true;
600
601	// Keep track of the last query for debug.
602	$this->last_query = $query;
603
604	// Save the query count after any charset discovery queries.
605	$last_query_count = count( $this->queries ?? array() );
606	$this->_do_query( $query );
607
608	if ( $this->last_error ) {
609	// Clear insert_id on a subsequent failed insert.
610	if ( $this->insert_id && preg_match( '/^\s*(insert\|replace)\s/i', $query ) ) {
611	$this->insert_id = 0;
612	}
613
614	$this->print_error();
615	return false;
616	}
617
618	if ( preg_match( '/^\s*(create\|alter\|truncate\|drop)\s/i', $query ) ) {
619	$return_val = true;
620	} elseif ( preg_match( '/^\s*(insert\|delete\|update\|replace)\s/i', $query ) ) {
621	$this->rows_affected = $this->result->rowCount();
622
623	// Take note of the insert_id.
624	if ( preg_match( '/^\s*(insert\|replace)\s/i', $query ) ) {
625	$this->insert_id = (int) $this->dbh->lastInsertId();
626	}
627
628	// Return number of rows affected.
629	$return_val = $this->rows_affected;
630	} else {
631	$num_rows = 0;
632
633	if ( $this->result->columnCount() > 0 ) {
634	$this->last_result = $this->result->fetchAll();
635	$num_rows = count( $this->last_result );
636	}
637
638	// Log and return the number of rows selected.
639	$this->num_rows = $num_rows;
640	$return_val = $num_rows;
641	}
642
643	// Query monitor integration:
644	if ( $query_monitor_active && class_exists( 'QM_Backtrace' ) ) {
645	if ( did_action( 'qm/cease' ) ) {
646	$this->queries = array();
647	}
648
649	$i = $last_query_count;
650	if ( ! isset( $this->queries[ $i ] ) ) {
651	return $return_val;
652	}
653
654	$this->queries[ $i ]['trace'] = new QM_Backtrace();
655	if ( ! isset( $this->queries[ $i ][3] ) ) {
656	$this->queries[ $i ][3] = $this->time_start;
657	}
658
659	if ( $this->last_error && ! $this->suppress_errors ) {
660	$this->queries[ $i ]['result'] = new WP_Error( 'qmdb', $this->last_error );
661	} else {
662	$this->queries[ $i ]['result'] = (int) $return_val;
663	}
664
665	// Add SQLite query data.
666	$this->queries[ $i ]['sqlite_queries'] = $this->dbh->get_last_sqlite_queries();
667	}
668	return $return_val;
669	}
670
671	/**
672	* Internal function to perform the SQLite query call.
673	*
674	* This closely mirrors wpdb::_do_query().
675	*
676	* @see wpdb::_do_query()
677	*
678	* @param string $query The query to run.
679	*/
680	private function _do_query( $query ) {
681	if ( defined( 'SAVEQUERIES' ) && SAVEQUERIES ) {
682	$this->timer_start();
683	}
684
685	try {
686	$this->result = $this->dbh->query( $query, PDO::FETCH_OBJ ); // phpcs:ignore WordPress.DB.RestrictedClasses.mysql__PDO
687	} catch ( Throwable $e ) {
688	$this->last_error = $this->format_error_message( $e );
689	}
690
691	++$this->num_queries;
692
693	if ( defined( 'SAVEQUERIES' ) && SAVEQUERIES ) {
694	$this->log_query(
695	$query,
696	$this->timer_stop(),
697	$this->get_caller(),
698	$this->time_start,
699	array()
700	);
701	}
702	}
703
704	/**
705	* Method to set the class variable $col_info.
706	*
707	* This overrides wpdb::load_col_info(), which uses a mysql function.
708	*
709	* @see wpdb::load_col_info()
710	*/
711	protected function load_col_info() {
712	if ( $this->col_info ) {
713	return;
714	}
715	$this->col_info = array();
716	if ( null === $this->result ) {
717	return;
718	}
719	for ( $i = 0; $i < $this->result->columnCount(); $i++ ) {
720	$column = $this->result->getColumnMeta( $i );
721	$this->col_info[] = (object) array(
722	'name' => $column['name'],
723	'orgname' => $column['mysqli:orgname'],
724	'table' => $column['table'],
725	'orgtable' => $column['mysqli:orgtable'],
726	'def' => '', // Unused, always ''.
727	'db' => $column['mysqli:db'],
728	'catalog' => 'def', // Unused, always 'def'.
729	'max_length' => 0, // As of PHP 8.1, this is always 0.
730	'length' => $column['len'],
731	'charsetnr' => $column['mysqli:charsetnr'],
732	'flags' => $column['mysqli:flags'],
733	'type' => $column['mysqli:type'],
734	'decimals' => $column['precision'],
735	);
736	}
737	}
738
739	/**
740	* Determines whether the database supports a given feature.
741	*
742	* The utf8mb4 check is handled here because older WordPress versions inspect
743	* the MySQL client library. All other capabilities use the parent logic.
744	*
745	* @see wpdb::has_cap()
746	*
747	* @param string $db_cap The feature to check for.
748	* @return bool True when the database feature is supported, false otherwise.
749	*/
750	public function has_cap( $db_cap ) {
751	if ( 'utf8mb4' === strtolower( $db_cap ) ) {
752	return true;
753	}
754
755	return parent::has_cap( $db_cap );
756	}
757
758	/**
759	* Retrieves the emulated database server version number.
760	*
761	* This mirrors wpdb::db_version(), but must also be defined here because
762	* WordPress 5.4 and older fetch server information directly from the MySQL
763	* extension instead of delegating to wpdb::db_server_info().
764	*
765	* @see wpdb::db_version()
766	*
767	* @return string Version number on success, or an empty string while disconnected.
768	*/
769	public function db_version() {
770	return preg_replace( '/[^0-9.].*/', '', $this->db_server_info() );
771	}
772
773	/**
774	* Returns the raw version string of the emulated MySQL server.
775	*
776	* @see wpdb::db_server_info()
777	*
778	* @return string Emulated MySQL server version, or an empty string while disconnected.
779	*/
780	public function db_server_info() {
781	if ( ! $this->dbh ) {
782	return '';
783	}
784
785	return $this->dbh->getAttribute( PDO::ATTR_SERVER_VERSION ); // phpcs:ignore WordPress.DB.RestrictedClasses.mysql__PDO
786	}
787
788	/**
789	* Make sure the SQLite database directory exists and is writable.
790	* Create .htaccess and index.php files to prevent direct access.
791	*
792	* @param string $database_path The path to the SQLite database file.
793	*/
794	private function ensure_database_directory( string $database_path ) {
795	$dir = dirname( $database_path );
796
797	// Set the umask to 0000 to apply permissions exactly as specified.
798	// A non-zero umask affects new file and directory permissions.
799	$umask = umask( 0 );
800
801	// Ensure database directory.
802	if ( ! is_dir( $dir ) ) {
803	if ( ! @mkdir( $dir, 0700, true ) ) {
804	wp_die( sprintf( 'Failed to create database directory: %s', $dir ), 'Error!' );
805	}
806	}
807	if ( ! is_writable( $dir ) ) {
808	wp_die( sprintf( 'Database directory is not writable: %s', $dir ), 'Error!' );
809	}
810
811	// Ensure .htaccess file to prevent direct access.
812	$path = $dir . DIRECTORY_SEPARATOR . '.htaccess';
813	if ( ! is_file( $path ) ) {
814	$result = file_put_contents( $path, 'DENY FROM ALL', LOCK_EX );
815	if ( false === $result ) {
816	wp_die( sprintf( 'Failed to create file: %s', $path ), 'Error!' );
817	}
818	chmod( $path, 0600 );
819	}
820
821	// Ensure index.php file to prevent direct access.
822	$path = $dir . DIRECTORY_SEPARATOR . 'index.php';
823	if ( ! is_file( $path ) ) {
824	$result = file_put_contents( $path, '<?php // Silence is gold. ?>', LOCK_EX );
825	if ( false === $result ) {
826	wp_die( sprintf( 'Failed to create file: %s', $path ), 'Error!' );
827	}
828	chmod( $path, 0600 );
829	}
830
831	// Restore the original umask value.
832	umask( $umask );
833	}
834
835
836	/**
837	* Format MySQL-on-SQLite driver error message.
838	*
839	* @return string
840	*/
841	private function format_error_message( Throwable $e ) {
842	$output = '<div style="clear:both"> </div>' . PHP_EOL;
843
844	// Queries.
845	if ( $e instanceof WP_MySQL_On_SQLite_Exception ) {
846	$driver = $e->get_driver();
847
848	$output .= '<div class="queries" style="clear:both;margin-bottom:2px;border:red dotted thin;">' . PHP_EOL;
849	$output .= '<p>MySQL query:</p>' . PHP_EOL;
850	$output .= '<p>' . $driver->get_last_mysql_query() . '</p>' . PHP_EOL;
851	$output .= '<p>Queries made or created this session were:</p>' . PHP_EOL;
852	$output .= '<ol>' . PHP_EOL;
853	foreach ( $driver->get_last_sqlite_queries() as $q ) {
854	$message = "Executing: {$q['sql']} \| " . ( $q['params'] ? 'parameters: ' . implode( ', ', $q['params'] ) : '(no parameters)' );
855	$output .= '<li>' . htmlspecialchars( $message ) . '</li>' . PHP_EOL;
856	}
857	$output .= '</ol>' . PHP_EOL;
858	$output .= '</div>' . PHP_EOL;
859	}
860
861	// Message.
862	$output .= '<div style="clear:both;margin-bottom:2px;border:red dotted thin;" class="error_message" style="border-bottom:dotted blue thin;">' . PHP_EOL;
863	$output .= $e->getMessage() . PHP_EOL;
864	$output .= '</div>' . PHP_EOL;
865
866	// Backtrace.
867	$output .= '<p>Backtrace:</p>' . PHP_EOL;
868	$output .= '<pre>' . $e->getTraceAsString() . '</pre>' . PHP_EOL;
869	return $output;
870	}
871	}
872