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[lhc/web/wiklou.git] / includes / db / Database.php
1 <?php
2 /**
3 * @defgroup Database Database
4 *
5 * @file
6 * @ingroup Database
7 * This file deals with MySQL interface functions
8 * and query specifics/optimisations
9 */
10
11 /** Number of times to re-try an operation in case of deadlock */
12 define( 'DEADLOCK_TRIES', 4 );
13 /** Minimum time to wait before retry, in microseconds */
14 define( 'DEADLOCK_DELAY_MIN', 500000 );
15 /** Maximum time to wait before retry */
16 define( 'DEADLOCK_DELAY_MAX', 1500000 );
17
18 /**
19 * Database abstraction object
20 * @ingroup Database
21 */
22 abstract class DatabaseBase {
23
24 #------------------------------------------------------------------------------
25 # Variables
26 #------------------------------------------------------------------------------
27
28 protected $mLastQuery = '';
29 protected $mDoneWrites = false;
30 protected $mPHPError = false;
31
32 protected $mServer, $mUser, $mPassword, $mConn = null, $mDBname;
33 protected $mOpened = false;
34
35 protected $mFailFunction;
36 protected $mTablePrefix;
37 protected $mFlags;
38 protected $mTrxLevel = 0;
39 protected $mErrorCount = 0;
40 protected $mLBInfo = array();
41 protected $mFakeSlaveLag = null, $mFakeMaster = false;
42 protected $mDefaultBigSelects = null;
43
44 #------------------------------------------------------------------------------
45 # Accessors
46 #------------------------------------------------------------------------------
47 # These optionally set a variable and return the previous state
48
49 /**
50 * Fail function, takes a Database as a parameter
51 * Set to false for default, 1 for ignore errors
52 */
53 function failFunction( $function = null ) {
54 return wfSetVar( $this->mFailFunction, $function );
55 }
56
57 /**
58 * Output page, used for reporting errors
59 * FALSE means discard output
60 */
61 function setOutputPage( $out ) {
62 wfDeprecated( __METHOD__ );
63 }
64
65 /**
66 * Boolean, controls output of large amounts of debug information
67 */
68 function debug( $debug = null ) {
69 return wfSetBit( $this->mFlags, DBO_DEBUG, $debug );
70 }
71
72 /**
73 * Turns buffering of SQL result sets on (true) or off (false).
74 * Default is "on" and it should not be changed without good reasons.
75 */
76 function bufferResults( $buffer = null ) {
77 if ( is_null( $buffer ) ) {
78 return !(bool)( $this->mFlags & DBO_NOBUFFER );
79 } else {
80 return !wfSetBit( $this->mFlags, DBO_NOBUFFER, !$buffer );
81 }
82 }
83
84 /**
85 * Turns on (false) or off (true) the automatic generation and sending
86 * of a "we're sorry, but there has been a database error" page on
87 * database errors. Default is on (false). When turned off, the
88 * code should use lastErrno() and lastError() to handle the
89 * situation as appropriate.
90 */
91 function ignoreErrors( $ignoreErrors = null ) {
92 return wfSetBit( $this->mFlags, DBO_IGNORE, $ignoreErrors );
93 }
94
95 /**
96 * The current depth of nested transactions
97 * @param $level Integer: , default NULL.
98 */
99 function trxLevel( $level = null ) {
100 return wfSetVar( $this->mTrxLevel, $level );
101 }
102
103 /**
104 * Number of errors logged, only useful when errors are ignored
105 */
106 function errorCount( $count = null ) {
107 return wfSetVar( $this->mErrorCount, $count );
108 }
109
110 function tablePrefix( $prefix = null ) {
111 return wfSetVar( $this->mTablePrefix, $prefix );
112 }
113
114 /**
115 * Properties passed down from the server info array of the load balancer
116 */
117 function getLBInfo( $name = null ) {
118 if ( is_null( $name ) ) {
119 return $this->mLBInfo;
120 } else {
121 if ( array_key_exists( $name, $this->mLBInfo ) ) {
122 return $this->mLBInfo[$name];
123 } else {
124 return null;
125 }
126 }
127 }
128
129 function setLBInfo( $name, $value = null ) {
130 if ( is_null( $value ) ) {
131 $this->mLBInfo = $name;
132 } else {
133 $this->mLBInfo[$name] = $value;
134 }
135 }
136
137 /**
138 * Set lag time in seconds for a fake slave
139 */
140 function setFakeSlaveLag( $lag ) {
141 $this->mFakeSlaveLag = $lag;
142 }
143
144 /**
145 * Make this connection a fake master
146 */
147 function setFakeMaster( $enabled = true ) {
148 $this->mFakeMaster = $enabled;
149 }
150
151 /**
152 * Returns true if this database supports (and uses) cascading deletes
153 */
154 function cascadingDeletes() {
155 return false;
156 }
157
158 /**
159 * Returns true if this database supports (and uses) triggers (e.g. on the page table)
160 */
161 function cleanupTriggers() {
162 return false;
163 }
164
165 /**
166 * Returns true if this database is strict about what can be put into an IP field.
167 * Specifically, it uses a NULL value instead of an empty string.
168 */
169 function strictIPs() {
170 return false;
171 }
172
173 /**
174 * Returns true if this database uses timestamps rather than integers
175 */
176 function realTimestamps() {
177 return false;
178 }
179
180 /**
181 * Returns true if this database does an implicit sort when doing GROUP BY
182 */
183 function implicitGroupby() {
184 return true;
185 }
186
187 /**
188 * Returns true if this database does an implicit order by when the column has an index
189 * For example: SELECT page_title FROM page LIMIT 1
190 */
191 function implicitOrderby() {
192 return true;
193 }
194
195 /**
196 * Returns true if this database requires that SELECT DISTINCT queries require that all
197 ORDER BY expressions occur in the SELECT list per the SQL92 standard
198 */
199 function standardSelectDistinct() {
200 return true;
201 }
202
203 /**
204 * Returns true if this database can do a native search on IP columns
205 * e.g. this works as expected: .. WHERE rc_ip = '127.42.12.102/32';
206 */
207 function searchableIPs() {
208 return false;
209 }
210
211 /**
212 * Returns true if this database can use functional indexes
213 */
214 function functionalIndexes() {
215 return false;
216 }
217
218 /**
219 * Return the last query that went through Database::query()
220 * @return String
221 */
222 function lastQuery() { return $this->mLastQuery; }
223
224
225 /**
226 * Returns true if the connection may have been used for write queries.
227 * Should return true if unsure.
228 */
229 function doneWrites() { return $this->mDoneWrites; }
230
231 /**
232 * Is a connection to the database open?
233 * @return Boolean
234 */
235 function isOpen() { return $this->mOpened; }
236
237 /**
238 * Set a flag for this connection
239 *
240 * @param $flag Integer: DBO_* constants from Defines.php:
241 * - DBO_DEBUG: output some debug info (same as debug())
242 * - DBO_NOBUFFER: don't buffer results (inverse of bufferResults())
243 * - DBO_IGNORE: ignore errors (same as ignoreErrors())
244 * - DBO_TRX: automatically start transactions
245 * - DBO_DEFAULT: automatically sets DBO_TRX if not in command line mode
246 * and removes it in command line mode
247 * - DBO_PERSISTENT: use persistant database connection
248 */
249 function setFlag( $flag ) {
250 $this->mFlags |= $flag;
251 }
252
253 /**
254 * Clear a flag for this connection
255 *
256 * @param $flag: same as setFlag()'s $flag param
257 */
258 function clearFlag( $flag ) {
259 $this->mFlags &= ~$flag;
260 }
261
262 /**
263 * Returns a boolean whether the flag $flag is set for this connection
264 *
265 * @param $flag: same as setFlag()'s $flag param
266 * @return Boolean
267 */
268 function getFlag( $flag ) {
269 return !!($this->mFlags & $flag);
270 }
271
272 /**
273 * General read-only accessor
274 */
275 function getProperty( $name ) {
276 return $this->$name;
277 }
278
279 function getWikiID() {
280 if( $this->mTablePrefix ) {
281 return "{$this->mDBname}-{$this->mTablePrefix}";
282 } else {
283 return $this->mDBname;
284 }
285 }
286
287 /**
288 * Get the type of the DBMS, as it appears in $wgDBtype.
289 */
290 abstract function getType();
291
292 #------------------------------------------------------------------------------
293 # Other functions
294 #------------------------------------------------------------------------------
295
296 /**
297 * Constructor.
298 * @param $server String: database server host
299 * @param $user String: database user name
300 * @param $password String: database user password
301 * @param $dbName String: database name
302 * @param $failFunction
303 * @param $flags
304 * @param $tablePrefix String: database table prefixes. By default use the prefix gave in LocalSettings.php
305 */
306 function __construct( $server = false, $user = false, $password = false, $dbName = false,
307 $failFunction = false, $flags = 0, $tablePrefix = 'get from global' ) {
308
309 global $wgOut, $wgDBprefix, $wgCommandLineMode;
310 # Can't get a reference if it hasn't been set yet
311 if ( !isset( $wgOut ) ) {
312 $wgOut = null;
313 }
314
315 $this->mFailFunction = $failFunction;
316 $this->mFlags = $flags;
317
318 if ( $this->mFlags & DBO_DEFAULT ) {
319 if ( $wgCommandLineMode ) {
320 $this->mFlags &= ~DBO_TRX;
321 } else {
322 $this->mFlags |= DBO_TRX;
323 }
324 }
325
326 /*
327 // Faster read-only access
328 if ( wfReadOnly() ) {
329 $this->mFlags |= DBO_PERSISTENT;
330 $this->mFlags &= ~DBO_TRX;
331 }*/
332
333 /** Get the default table prefix*/
334 if ( $tablePrefix == 'get from global' ) {
335 $this->mTablePrefix = $wgDBprefix;
336 } else {
337 $this->mTablePrefix = $tablePrefix;
338 }
339
340 if ( $server ) {
341 $this->open( $server, $user, $password, $dbName );
342 }
343 }
344
345 /**
346 * Same as new DatabaseMysql( ... ), kept for backward compatibility
347 * @param $server String: database server host
348 * @param $user String: database user name
349 * @param $password String: database user password
350 * @param $dbName String: database name
351 * @param failFunction
352 * @param $flags
353 */
354 static function newFromParams( $server, $user, $password, $dbName, $failFunction = false, $flags = 0 )
355 {
356 return new DatabaseMysql( $server, $user, $password, $dbName, $failFunction, $flags );
357 }
358
359 /**
360 * Usually aborts on failure
361 * If the failFunction is set to a non-zero integer, returns success
362 * @param $server String: database server host
363 * @param $user String: database user name
364 * @param $password String: database user password
365 * @param $dbName String: database name
366 */
367 abstract function open( $server, $user, $password, $dbName );
368
369 protected function installErrorHandler() {
370 $this->mPHPError = false;
371 $this->htmlErrors = ini_set( 'html_errors', '0' );
372 set_error_handler( array( $this, 'connectionErrorHandler' ) );
373 }
374
375 protected function restoreErrorHandler() {
376 restore_error_handler();
377 if ( $this->htmlErrors !== false ) {
378 ini_set( 'html_errors', $this->htmlErrors );
379 }
380 if ( $this->mPHPError ) {
381 $error = preg_replace( '!\[<a.*</a>\]!', '', $this->mPHPError );
382 $error = preg_replace( '!^.*?:(.*)$!', '$1', $error );
383 return $error;
384 } else {
385 return false;
386 }
387 }
388
389 protected function connectionErrorHandler( $errno, $errstr ) {
390 $this->mPHPError = $errstr;
391 }
392
393 /**
394 * Closes a database connection.
395 * if it is open : commits any open transactions
396 *
397 * @return Bool operation success. true if already closed.
398 */
399 function close() {
400 # Stub, should probably be overridden
401 return true;
402 }
403
404 /**
405 * @param $error String: fallback error message, used if none is given by MySQL
406 */
407 function reportConnectionError( $error = 'Unknown error' ) {
408 $myError = $this->lastError();
409 if ( $myError ) {
410 $error = $myError;
411 }
412
413 if ( $this->mFailFunction ) {
414 # Legacy error handling method
415 if ( !is_int( $this->mFailFunction ) ) {
416 $ff = $this->mFailFunction;
417 $ff( $this, $error );
418 }
419 } else {
420 # New method
421 throw new DBConnectionError( $this, $error );
422 }
423 }
424
425 /**
426 * Determine whether a query writes to the DB.
427 * Should return true if unsure.
428 */
429 function isWriteQuery( $sql ) {
430 return !preg_match( '/^(?:SELECT|BEGIN|COMMIT|SET|SHOW|\(SELECT)\b/i', $sql );
431 }
432
433 /**
434 * Usually aborts on failure. If errors are explicitly ignored, returns success.
435 *
436 * @param $sql String: SQL query
437 * @param $fname String: Name of the calling function, for profiling/SHOW PROCESSLIST
438 * comment (you can use __METHOD__ or add some extra info)
439 * @param $tempIgnore Boolean: Whether to avoid throwing an exception on errors...
440 * maybe best to catch the exception instead?
441 * @return true for a successful write query, ResultWrapper object for a successful read query,
442 * or false on failure if $tempIgnore set
443 * @throws DBQueryError Thrown when the database returns an error of any kind
444 */
445 public function query( $sql, $fname = '', $tempIgnore = false ) {
446 global $wgProfiler;
447
448 $isMaster = !is_null( $this->getLBInfo( 'master' ) );
449 if ( isset( $wgProfiler ) ) {
450 # generalizeSQL will probably cut down the query to reasonable
451 # logging size most of the time. The substr is really just a sanity check.
452
453 # Who's been wasting my precious column space? -- TS
454 #$profName = 'query: ' . $fname . ' ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
455
456 if ( $isMaster ) {
457 $queryProf = 'query-m: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
458 $totalProf = 'Database::query-master';
459 } else {
460 $queryProf = 'query: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
461 $totalProf = 'Database::query';
462 }
463 wfProfileIn( $totalProf );
464 wfProfileIn( $queryProf );
465 }
466
467 $this->mLastQuery = $sql;
468 if ( !$this->mDoneWrites && $this->isWriteQuery( $sql ) ) {
469 // Set a flag indicating that writes have been done
470 wfDebug( __METHOD__.": Writes done: $sql\n" );
471 $this->mDoneWrites = true;
472 }
473
474 # Add a comment for easy SHOW PROCESSLIST interpretation
475 #if ( $fname ) {
476 global $wgUser;
477 if ( is_object( $wgUser ) && !($wgUser instanceof StubObject) ) {
478 $userName = $wgUser->getName();
479 if ( mb_strlen( $userName ) > 15 ) {
480 $userName = mb_substr( $userName, 0, 15 ) . '...';
481 }
482 $userName = str_replace( '/', '', $userName );
483 } else {
484 $userName = '';
485 }
486 $commentedSql = preg_replace('/\s/', " /* $fname $userName */ ", $sql, 1);
487 #} else {
488 # $commentedSql = $sql;
489 #}
490
491 # If DBO_TRX is set, start a transaction
492 if ( ( $this->mFlags & DBO_TRX ) && !$this->trxLevel() &&
493 $sql != 'BEGIN' && $sql != 'COMMIT' && $sql != 'ROLLBACK') {
494 // avoid establishing transactions for SHOW and SET statements too -
495 // that would delay transaction initializations to once connection
496 // is really used by application
497 $sqlstart = substr($sql,0,10); // very much worth it, benchmark certified(tm)
498 if (strpos($sqlstart,"SHOW ")!==0 and strpos($sqlstart,"SET ")!==0)
499 $this->begin();
500 }
501
502 if ( $this->debug() ) {
503 $sqlx = substr( $commentedSql, 0, 500 );
504 $sqlx = strtr( $sqlx, "\t\n", ' ' );
505 if ( $isMaster ) {
506 wfDebug( "SQL-master: $sqlx\n" );
507 } else {
508 wfDebug( "SQL: $sqlx\n" );
509 }
510 }
511
512 if ( istainted( $sql ) & TC_MYSQL ) {
513 throw new MWException( 'Tainted query found' );
514 }
515
516 # Do the query and handle errors
517 $ret = $this->doQuery( $commentedSql );
518
519 # Try reconnecting if the connection was lost
520 if ( false === $ret && $this->wasErrorReissuable() ) {
521 # Transaction is gone, like it or not
522 $this->mTrxLevel = 0;
523 wfDebug( "Connection lost, reconnecting...\n" );
524 if ( $this->ping() ) {
525 wfDebug( "Reconnected\n" );
526 $sqlx = substr( $commentedSql, 0, 500 );
527 $sqlx = strtr( $sqlx, "\t\n", ' ' );
528 global $wgRequestTime;
529 $elapsed = round( microtime(true) - $wgRequestTime, 3 );
530 wfLogDBError( "Connection lost and reconnected after {$elapsed}s, query: $sqlx\n" );
531 $ret = $this->doQuery( $commentedSql );
532 } else {
533 wfDebug( "Failed\n" );
534 }
535 }
536
537 if ( false === $ret ) {
538 $this->reportQueryError( $this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
539 }
540
541 if ( isset( $wgProfiler ) ) {
542 wfProfileOut( $queryProf );
543 wfProfileOut( $totalProf );
544 }
545 return $this->resultObject( $ret );
546 }
547
548 /**
549 * The DBMS-dependent part of query()
550 * @param $sql String: SQL query.
551 * @return Result object to feed to fetchObject, fetchRow, ...; or false on failure
552 * @private
553 */
554 /*private*/ abstract function doQuery( $sql );
555
556 /**
557 * @param $error String
558 * @param $errno Integer
559 * @param $sql String
560 * @param $fname String
561 * @param $tempIgnore Boolean
562 */
563 function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
564 global $wgCommandLineMode;
565 # Ignore errors during error handling to avoid infinite recursion
566 $ignore = $this->ignoreErrors( true );
567 ++$this->mErrorCount;
568
569 if( $ignore || $tempIgnore ) {
570 wfDebug("SQL ERROR (ignored): $error\n");
571 $this->ignoreErrors( $ignore );
572 } else {
573 $sql1line = str_replace( "\n", "\\n", $sql );
574 wfLogDBError("$fname\t{$this->mServer}\t$errno\t$error\t$sql1line\n");
575 wfDebug("SQL ERROR: " . $error . "\n");
576 throw new DBQueryError( $this, $error, $errno, $sql, $fname );
577 }
578 }
579
580
581 /**
582 * Intended to be compatible with the PEAR::DB wrapper functions.
583 * http://pear.php.net/manual/en/package.database.db.intro-execute.php
584 *
585 * ? = scalar value, quoted as necessary
586 * ! = raw SQL bit (a function for instance)
587 * & = filename; reads the file and inserts as a blob
588 * (we don't use this though...)
589 */
590 function prepare( $sql, $func = 'Database::prepare' ) {
591 /* MySQL doesn't support prepared statements (yet), so just
592 pack up the query for reference. We'll manually replace
593 the bits later. */
594 return array( 'query' => $sql, 'func' => $func );
595 }
596
597 function freePrepared( $prepared ) {
598 /* No-op for MySQL */
599 }
600
601 /**
602 * Execute a prepared query with the various arguments
603 * @param $prepared String: the prepared sql
604 * @param $args Mixed: Either an array here, or put scalars as varargs
605 */
606 function execute( $prepared, $args = null ) {
607 if( !is_array( $args ) ) {
608 # Pull the var args
609 $args = func_get_args();
610 array_shift( $args );
611 }
612 $sql = $this->fillPrepared( $prepared['query'], $args );
613 return $this->query( $sql, $prepared['func'] );
614 }
615
616 /**
617 * Prepare & execute an SQL statement, quoting and inserting arguments
618 * in the appropriate places.
619 * @param $query String
620 * @param $args ...
621 */
622 function safeQuery( $query, $args = null ) {
623 $prepared = $this->prepare( $query, 'Database::safeQuery' );
624 if( !is_array( $args ) ) {
625 # Pull the var args
626 $args = func_get_args();
627 array_shift( $args );
628 }
629 $retval = $this->execute( $prepared, $args );
630 $this->freePrepared( $prepared );
631 return $retval;
632 }
633
634 /**
635 * For faking prepared SQL statements on DBs that don't support
636 * it directly.
637 * @param $preparedQuery String: a 'preparable' SQL statement
638 * @param $args Array of arguments to fill it with
639 * @return string executable SQL
640 */
641 function fillPrepared( $preparedQuery, $args ) {
642 reset( $args );
643 $this->preparedArgs =& $args;
644 return preg_replace_callback( '/(\\\\[?!&]|[?!&])/',
645 array( &$this, 'fillPreparedArg' ), $preparedQuery );
646 }
647
648 /**
649 * preg_callback func for fillPrepared()
650 * The arguments should be in $this->preparedArgs and must not be touched
651 * while we're doing this.
652 *
653 * @param $matches Array
654 * @return String
655 * @private
656 */
657 function fillPreparedArg( $matches ) {
658 switch( $matches[1] ) {
659 case '\\?': return '?';
660 case '\\!': return '!';
661 case '\\&': return '&';
662 }
663 list( /* $n */ , $arg ) = each( $this->preparedArgs );
664 switch( $matches[1] ) {
665 case '?': return $this->addQuotes( $arg );
666 case '!': return $arg;
667 case '&':
668 # return $this->addQuotes( file_get_contents( $arg ) );
669 throw new DBUnexpectedError( $this, '& mode is not implemented. If it\'s really needed, uncomment the line above.' );
670 default:
671 throw new DBUnexpectedError( $this, 'Received invalid match. This should never happen!' );
672 }
673 }
674
675 /**
676 * Free a result object
677 * @param $res Mixed: A SQL result
678 */
679 function freeResult( $res ) {
680 # Stub. Might not really need to be overridden, since results should
681 # be freed by PHP when the variable goes out of scope anyway.
682 }
683
684 /**
685 * Fetch the next row from the given result object, in object form.
686 * Fields can be retrieved with $row->fieldname, with fields acting like
687 * member variables.
688 *
689 * @param $res SQL result object as returned from Database::query(), etc.
690 * @return MySQL row object
691 * @throws DBUnexpectedError Thrown if the database returns an error
692 */
693 abstract function fetchObject( $res );
694
695 /**
696 * Fetch the next row from the given result object, in associative array
697 * form. Fields are retrieved with $row['fieldname'].
698 *
699 * @param $res SQL result object as returned from Database::query(), etc.
700 * @return MySQL row object
701 * @throws DBUnexpectedError Thrown if the database returns an error
702 */
703 abstract function fetchRow( $res );
704
705 /**
706 * Get the number of rows in a result object
707 * @param $res Mixed: A SQL result
708 */
709 abstract function numRows( $res );
710
711 /**
712 * Get the number of fields in a result object
713 * See documentation for mysql_num_fields()
714 * @param $res Mixed: A SQL result
715 */
716 abstract function numFields( $res );
717
718 /**
719 * Get a field name in a result object
720 * See documentation for mysql_field_name():
721 * http://www.php.net/mysql_field_name
722 * @param $res Mixed: A SQL result
723 * @param $n Integer
724 */
725 abstract function fieldName( $res, $n );
726
727 /**
728 * Get the inserted value of an auto-increment row
729 *
730 * The value inserted should be fetched from nextSequenceValue()
731 *
732 * Example:
733 * $id = $dbw->nextSequenceValue('page_page_id_seq');
734 * $dbw->insert('page',array('page_id' => $id));
735 * $id = $dbw->insertId();
736 */
737 abstract function insertId();
738
739 /**
740 * Change the position of the cursor in a result object
741 * See mysql_data_seek()
742 * @param $res Mixed: A SQL result
743 * @param $row Mixed: Either MySQL row or ResultWrapper
744 */
745 abstract function dataSeek( $res, $row );
746
747 /**
748 * Get the last error number
749 * See mysql_errno()
750 */
751 abstract function lastErrno();
752
753 /**
754 * Get a description of the last error
755 * See mysql_error() for more details
756 */
757 abstract function lastError();
758
759 /**
760 * Get the number of rows affected by the last write query
761 * See mysql_affected_rows() for more details
762 */
763 abstract function affectedRows();
764
765 /**
766 * Simple UPDATE wrapper
767 * Usually aborts on failure
768 * If errors are explicitly ignored, returns success
769 *
770 * This function exists for historical reasons, Database::update() has a more standard
771 * calling convention and feature set
772 */
773 function set( $table, $var, $value, $cond, $fname = 'Database::set' ) {
774 $table = $this->tableName( $table );
775 $sql = "UPDATE $table SET $var = '" .
776 $this->strencode( $value ) . "' WHERE ($cond)";
777 return (bool)$this->query( $sql, $fname );
778 }
779
780 /**
781 * Simple SELECT wrapper, returns a single field, input must be encoded
782 * Usually aborts on failure
783 * If errors are explicitly ignored, returns FALSE on failure
784 */
785 function selectField( $table, $var, $cond='', $fname = 'Database::selectField', $options = array() ) {
786 if ( !is_array( $options ) ) {
787 $options = array( $options );
788 }
789 $options['LIMIT'] = 1;
790
791 $res = $this->select( $table, $var, $cond, $fname, $options );
792 if ( $res === false || !$this->numRows( $res ) ) {
793 return false;
794 }
795 $row = $this->fetchRow( $res );
796 if ( $row !== false ) {
797 $this->freeResult( $res );
798 return reset( $row );
799 } else {
800 return false;
801 }
802 }
803
804 /**
805 * Returns an optional USE INDEX clause to go after the table, and a
806 * string to go at the end of the query
807 *
808 * @private
809 *
810 * @param $options Array: associative array of options to be turned into
811 * an SQL query, valid keys are listed in the function.
812 * @return Array
813 */
814 function makeSelectOptions( $options ) {
815 $preLimitTail = $postLimitTail = '';
816 $startOpts = '';
817
818 $noKeyOptions = array();
819 foreach ( $options as $key => $option ) {
820 if ( is_numeric( $key ) ) {
821 $noKeyOptions[$option] = true;
822 }
823 }
824
825 if ( isset( $options['GROUP BY'] ) ) $preLimitTail .= " GROUP BY {$options['GROUP BY']}";
826 if ( isset( $options['HAVING'] ) ) $preLimitTail .= " HAVING {$options['HAVING']}";
827 if ( isset( $options['ORDER BY'] ) ) $preLimitTail .= " ORDER BY {$options['ORDER BY']}";
828
829 //if (isset($options['LIMIT'])) {
830 // $tailOpts .= $this->limitResult('', $options['LIMIT'],
831 // isset($options['OFFSET']) ? $options['OFFSET']
832 // : false);
833 //}
834
835 if ( isset( $noKeyOptions['FOR UPDATE'] ) ) $postLimitTail .= ' FOR UPDATE';
836 if ( isset( $noKeyOptions['LOCK IN SHARE MODE'] ) ) $postLimitTail .= ' LOCK IN SHARE MODE';
837 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) $startOpts .= 'DISTINCT';
838
839 # Various MySQL extensions
840 if ( isset( $noKeyOptions['STRAIGHT_JOIN'] ) ) $startOpts .= ' /*! STRAIGHT_JOIN */';
841 if ( isset( $noKeyOptions['HIGH_PRIORITY'] ) ) $startOpts .= ' HIGH_PRIORITY';
842 if ( isset( $noKeyOptions['SQL_BIG_RESULT'] ) ) $startOpts .= ' SQL_BIG_RESULT';
843 if ( isset( $noKeyOptions['SQL_BUFFER_RESULT'] ) ) $startOpts .= ' SQL_BUFFER_RESULT';
844 if ( isset( $noKeyOptions['SQL_SMALL_RESULT'] ) ) $startOpts .= ' SQL_SMALL_RESULT';
845 if ( isset( $noKeyOptions['SQL_CALC_FOUND_ROWS'] ) ) $startOpts .= ' SQL_CALC_FOUND_ROWS';
846 if ( isset( $noKeyOptions['SQL_CACHE'] ) ) $startOpts .= ' SQL_CACHE';
847 if ( isset( $noKeyOptions['SQL_NO_CACHE'] ) ) $startOpts .= ' SQL_NO_CACHE';
848
849 if ( isset( $options['USE INDEX'] ) && ! is_array( $options['USE INDEX'] ) ) {
850 $useIndex = $this->useIndexClause( $options['USE INDEX'] );
851 } else {
852 $useIndex = '';
853 }
854
855 return array( $startOpts, $useIndex, $preLimitTail, $postLimitTail );
856 }
857
858 /**
859 * SELECT wrapper
860 *
861 * @param $table Mixed: Array or string, table name(s) (prefix auto-added)
862 * @param $vars Mixed: Array or string, field name(s) to be retrieved
863 * @param $conds Mixed: Array or string, condition(s) for WHERE
864 * @param $fname String: Calling function name (use __METHOD__) for logs/profiling
865 * @param $options Array: Associative array of options (e.g. array('GROUP BY' => 'page_title')),
866 * see Database::makeSelectOptions code for list of supported stuff
867 * @param $join_conds Array: Associative array of table join conditions (optional)
868 * (e.g. array( 'page' => array('LEFT JOIN','page_latest=rev_id') )
869 * @return mixed Database result resource (feed to Database::fetchObject or whatever), or false on failure
870 */
871 function select( $table, $vars, $conds='', $fname = 'Database::select', $options = array(), $join_conds = array() )
872 {
873 $sql = $this->selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
874 return $this->query( $sql, $fname );
875 }
876
877 /**
878 * SELECT wrapper
879 *
880 * @param $table Mixed: Array or string, table name(s) (prefix auto-added)
881 * @param $vars Mixed: Array or string, field name(s) to be retrieved
882 * @param $conds Mixed: Array or string, condition(s) for WHERE
883 * @param $fname String: Calling function name (use __METHOD__) for logs/profiling
884 * @param $options Array: Associative array of options (e.g. array('GROUP BY' => 'page_title')),
885 * see Database::makeSelectOptions code for list of supported stuff
886 * @param $join_conds Array: Associative array of table join conditions (optional)
887 * (e.g. array( 'page' => array('LEFT JOIN','page_latest=rev_id') )
888 * @return string, the SQL text
889 */
890 function selectSQLText( $table, $vars, $conds='', $fname = 'Database::select', $options = array(), $join_conds = array() ) {
891 if( is_array( $vars ) ) {
892 $vars = implode( ',', $vars );
893 }
894 if( !is_array( $options ) ) {
895 $options = array( $options );
896 }
897 if( is_array( $table ) ) {
898 if ( !empty($join_conds) || ( isset( $options['USE INDEX'] ) && is_array( @$options['USE INDEX'] ) ) )
899 $from = ' FROM ' . $this->tableNamesWithUseIndexOrJOIN( $table, @$options['USE INDEX'], $join_conds );
900 else
901 $from = ' FROM ' . implode( ',', array_map( array( &$this, 'tableName' ), $table ) );
902 } elseif ($table!='') {
903 if ($table{0}==' ') {
904 $from = ' FROM ' . $table;
905 } else {
906 $from = ' FROM ' . $this->tableName( $table );
907 }
908 } else {
909 $from = '';
910 }
911
912 list( $startOpts, $useIndex, $preLimitTail, $postLimitTail ) = $this->makeSelectOptions( $options );
913
914 if( !empty( $conds ) ) {
915 if ( is_array( $conds ) ) {
916 $conds = $this->makeList( $conds, LIST_AND );
917 }
918 $sql = "SELECT $startOpts $vars $from $useIndex WHERE $conds $preLimitTail";
919 } else {
920 $sql = "SELECT $startOpts $vars $from $useIndex $preLimitTail";
921 }
922
923 if (isset($options['LIMIT']))
924 $sql = $this->limitResult($sql, $options['LIMIT'],
925 isset($options['OFFSET']) ? $options['OFFSET'] : false);
926 $sql = "$sql $postLimitTail";
927
928 if (isset($options['EXPLAIN'])) {
929 $sql = 'EXPLAIN ' . $sql;
930 }
931 return $sql;
932 }
933
934 /**
935 * Single row SELECT wrapper
936 * Aborts or returns FALSE on error
937 *
938 * @param $table String: table name
939 * @param $vars String: the selected variables
940 * @param $conds Array: a condition map, terms are ANDed together.
941 * Items with numeric keys are taken to be literal conditions
942 * Takes an array of selected variables, and a condition map, which is ANDed
943 * e.g: selectRow( "page", array( "page_id" ), array( "page_namespace" =>
944 * NS_MAIN, "page_title" => "Astronomy" ) ) would return an object where
945 * $obj- >page_id is the ID of the Astronomy article
946 * @param $fname String: Calling function name
947 * @param $options Array
948 * @param $join_conds Array
949 *
950 * @todo migrate documentation to phpdocumentor format
951 */
952 function selectRow( $table, $vars, $conds, $fname = 'Database::selectRow', $options = array(), $join_conds = array() ) {
953 $options['LIMIT'] = 1;
954 $res = $this->select( $table, $vars, $conds, $fname, $options, $join_conds );
955 if ( $res === false )
956 return false;
957 if ( !$this->numRows($res) ) {
958 $this->freeResult($res);
959 return false;
960 }
961 $obj = $this->fetchObject( $res );
962 $this->freeResult( $res );
963 return $obj;
964
965 }
966
967 /**
968 * Estimate rows in dataset
969 * Returns estimated count - not necessarily an accurate estimate across different databases,
970 * so use sparingly
971 * Takes same arguments as Database::select()
972 *
973 * @param string $table table name
974 * @param array $vars unused
975 * @param array $conds filters on the table
976 * @param string $fname function name for profiling
977 * @param array $options options for select
978 * @return int row count
979 */
980 public function estimateRowCount( $table, $vars='*', $conds='', $fname = 'Database::estimateRowCount', $options = array() ) {
981 $rows = 0;
982 $res = $this->select ( $table, 'COUNT(*) AS rowcount', $conds, $fname, $options );
983 if ( $res ) {
984 $row = $this->fetchRow( $res );
985 $rows = ( isset( $row['rowcount'] ) ) ? $row['rowcount'] : 0;
986 }
987 $this->freeResult( $res );
988 return $rows;
989 }
990
991 /**
992 * Removes most variables from an SQL query and replaces them with X or N for numbers.
993 * It's only slightly flawed. Don't use for anything important.
994 *
995 * @param $sql String: A SQL Query
996 */
997 static function generalizeSQL( $sql ) {
998 # This does the same as the regexp below would do, but in such a way
999 # as to avoid crashing php on some large strings.
1000 # $sql = preg_replace ( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql);
1001
1002 $sql = str_replace ( "\\\\", '', $sql);
1003 $sql = str_replace ( "\\'", '', $sql);
1004 $sql = str_replace ( "\\\"", '', $sql);
1005 $sql = preg_replace ("/'.*'/s", "'X'", $sql);
1006 $sql = preg_replace ('/".*"/s', "'X'", $sql);
1007
1008 # All newlines, tabs, etc replaced by single space
1009 $sql = preg_replace ( '/\s+/', ' ', $sql);
1010
1011 # All numbers => N
1012 $sql = preg_replace ('/-?[0-9]+/s', 'N', $sql);
1013
1014 return $sql;
1015 }
1016
1017 /**
1018 * Determines whether a field exists in a table
1019 * Usually aborts on failure
1020 * If errors are explicitly ignored, returns NULL on failure
1021 */
1022 function fieldExists( $table, $field, $fname = 'Database::fieldExists' ) {
1023 $table = $this->tableName( $table );
1024 $res = $this->query( 'DESCRIBE '.$table, $fname );
1025 if ( !$res ) {
1026 return null;
1027 }
1028
1029 $found = false;
1030
1031 while ( $row = $this->fetchObject( $res ) ) {
1032 if ( $row->Field == $field ) {
1033 $found = true;
1034 break;
1035 }
1036 }
1037 return $found;
1038 }
1039
1040 /**
1041 * Determines whether an index exists
1042 * Usually aborts on failure
1043 * If errors are explicitly ignored, returns NULL on failure
1044 */
1045 function indexExists( $table, $index, $fname = 'Database::indexExists' ) {
1046 $info = $this->indexInfo( $table, $index, $fname );
1047 if ( is_null( $info ) ) {
1048 return null;
1049 } else {
1050 return $info !== false;
1051 }
1052 }
1053
1054
1055 /**
1056 * Get information about an index into an object
1057 * Returns false if the index does not exist
1058 */
1059 function indexInfo( $table, $index, $fname = 'Database::indexInfo' ) {
1060 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
1061 # SHOW INDEX should work for 3.x and up:
1062 # http://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
1063 $table = $this->tableName( $table );
1064 $index = $this->indexName( $index );
1065 $sql = 'SHOW INDEX FROM '.$table;
1066 $res = $this->query( $sql, $fname );
1067 if ( !$res ) {
1068 return null;
1069 }
1070
1071 $result = array();
1072 while ( $row = $this->fetchObject( $res ) ) {
1073 if ( $row->Key_name == $index ) {
1074 $result[] = $row;
1075 }
1076 }
1077 $this->freeResult($res);
1078
1079 return empty($result) ? false : $result;
1080 }
1081
1082 /**
1083 * Query whether a given table exists
1084 */
1085 function tableExists( $table ) {
1086 $table = $this->tableName( $table );
1087 $old = $this->ignoreErrors( true );
1088 $res = $this->query( "SELECT 1 FROM $table LIMIT 1" );
1089 $this->ignoreErrors( $old );
1090 if( $res ) {
1091 $this->freeResult( $res );
1092 return true;
1093 } else {
1094 return false;
1095 }
1096 }
1097
1098 /**
1099 * mysql_fetch_field() wrapper
1100 * Returns false if the field doesn't exist
1101 *
1102 * @param $table
1103 * @param $field
1104 */
1105 abstract function fieldInfo( $table, $field );
1106
1107 /**
1108 * mysql_field_type() wrapper
1109 */
1110 function fieldType( $res, $index ) {
1111 if ( $res instanceof ResultWrapper ) {
1112 $res = $res->result;
1113 }
1114 return mysql_field_type( $res, $index );
1115 }
1116
1117 /**
1118 * Determines if a given index is unique
1119 */
1120 function indexUnique( $table, $index ) {
1121 $indexInfo = $this->indexInfo( $table, $index );
1122 if ( !$indexInfo ) {
1123 return null;
1124 }
1125 return !$indexInfo[0]->Non_unique;
1126 }
1127
1128 /**
1129 * INSERT wrapper, inserts an array into a table
1130 *
1131 * $a may be a single associative array, or an array of these with numeric keys, for
1132 * multi-row insert.
1133 *
1134 * Usually aborts on failure
1135 * If errors are explicitly ignored, returns success
1136 */
1137 function insert( $table, $a, $fname = 'Database::insert', $options = array() ) {
1138 # No rows to insert, easy just return now
1139 if ( !count( $a ) ) {
1140 return true;
1141 }
1142
1143 $table = $this->tableName( $table );
1144 if ( !is_array( $options ) ) {
1145 $options = array( $options );
1146 }
1147 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
1148 $multi = true;
1149 $keys = array_keys( $a[0] );
1150 } else {
1151 $multi = false;
1152 $keys = array_keys( $a );
1153 }
1154
1155 $sql = 'INSERT ' . implode( ' ', $options ) .
1156 " INTO $table (" . implode( ',', $keys ) . ') VALUES ';
1157
1158 if ( $multi ) {
1159 $first = true;
1160 foreach ( $a as $row ) {
1161 if ( $first ) {
1162 $first = false;
1163 } else {
1164 $sql .= ',';
1165 }
1166 $sql .= '(' . $this->makeList( $row ) . ')';
1167 }
1168 } else {
1169 $sql .= '(' . $this->makeList( $a ) . ')';
1170 }
1171 return (bool)$this->query( $sql, $fname );
1172 }
1173
1174 /**
1175 * Make UPDATE options for the Database::update function
1176 *
1177 * @private
1178 * @param $options Array: The options passed to Database::update
1179 * @return string
1180 */
1181 function makeUpdateOptions( $options ) {
1182 if( !is_array( $options ) ) {
1183 $options = array( $options );
1184 }
1185 $opts = array();
1186 if ( in_array( 'LOW_PRIORITY', $options ) )
1187 $opts[] = $this->lowPriorityOption();
1188 if ( in_array( 'IGNORE', $options ) )
1189 $opts[] = 'IGNORE';
1190 return implode(' ', $opts);
1191 }
1192
1193 /**
1194 * UPDATE wrapper, takes a condition array and a SET array
1195 *
1196 * @param $table String: The table to UPDATE
1197 * @param $values Array: An array of values to SET
1198 * @param $conds Array: An array of conditions (WHERE). Use '*' to update all rows.
1199 * @param $fname String: The Class::Function calling this function
1200 * (for the log)
1201 * @param $options Array: An array of UPDATE options, can be one or
1202 * more of IGNORE, LOW_PRIORITY
1203 * @return Boolean
1204 */
1205 function update( $table, $values, $conds, $fname = 'Database::update', $options = array() ) {
1206 $table = $this->tableName( $table );
1207 $opts = $this->makeUpdateOptions( $options );
1208 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET );
1209 if ( $conds != '*' ) {
1210 $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1211 }
1212 return $this->query( $sql, $fname );
1213 }
1214
1215 /**
1216 * Makes an encoded list of strings from an array
1217 * $mode:
1218 * LIST_COMMA - comma separated, no field names
1219 * LIST_AND - ANDed WHERE clause (without the WHERE)
1220 * LIST_OR - ORed WHERE clause (without the WHERE)
1221 * LIST_SET - comma separated with field names, like a SET clause
1222 * LIST_NAMES - comma separated field names
1223 */
1224 function makeList( $a, $mode = LIST_COMMA ) {
1225 if ( !is_array( $a ) ) {
1226 throw new DBUnexpectedError( $this, 'Database::makeList called with incorrect parameters' );
1227 }
1228
1229 $first = true;
1230 $list = '';
1231 foreach ( $a as $field => $value ) {
1232 if ( !$first ) {
1233 if ( $mode == LIST_AND ) {
1234 $list .= ' AND ';
1235 } elseif($mode == LIST_OR) {
1236 $list .= ' OR ';
1237 } else {
1238 $list .= ',';
1239 }
1240 } else {
1241 $first = false;
1242 }
1243 if ( ($mode == LIST_AND || $mode == LIST_OR) && is_numeric( $field ) ) {
1244 $list .= "($value)";
1245 } elseif ( ($mode == LIST_SET) && is_numeric( $field ) ) {
1246 $list .= "$value";
1247 } elseif ( ($mode == LIST_AND || $mode == LIST_OR) && is_array($value) ) {
1248 if( count( $value ) == 0 ) {
1249 throw new MWException( __METHOD__.': empty input' );
1250 } elseif( count( $value ) == 1 ) {
1251 // Special-case single values, as IN isn't terribly efficient
1252 // Don't necessarily assume the single key is 0; we don't
1253 // enforce linear numeric ordering on other arrays here.
1254 $value = array_values( $value );
1255 $list .= $field." = ".$this->addQuotes( $value[0] );
1256 } else {
1257 $list .= $field." IN (".$this->makeList($value).") ";
1258 }
1259 } elseif( $value === null ) {
1260 if ( $mode == LIST_AND || $mode == LIST_OR ) {
1261 $list .= "$field IS ";
1262 } elseif ( $mode == LIST_SET ) {
1263 $list .= "$field = ";
1264 }
1265 $list .= 'NULL';
1266 } else {
1267 if ( $mode == LIST_AND || $mode == LIST_OR || $mode == LIST_SET ) {
1268 $list .= "$field = ";
1269 }
1270 $list .= $mode == LIST_NAMES ? $value : $this->addQuotes( $value );
1271 }
1272 }
1273 return $list;
1274 }
1275
1276 /**
1277 * Bitwise operations
1278 */
1279
1280 function bitNot($field) {
1281 return "(~$bitField)";
1282 }
1283
1284 function bitAnd($fieldLeft, $fieldRight) {
1285 return "($fieldLeft & $fieldRight)";
1286 }
1287
1288 function bitOr($fieldLeft, $fieldRight) {
1289 return "($fieldLeft | $fieldRight)";
1290 }
1291
1292 /**
1293 * Change the current database
1294 *
1295 * @return bool Success or failure
1296 */
1297 function selectDB( $db ) {
1298 # Stub. Shouldn't cause serious problems if it's not overridden, but
1299 # if your database engine supports a concept similar to MySQL's
1300 # databases you may as well. TODO: explain what exactly will fail if
1301 # this is not overridden.
1302 return true;
1303 }
1304
1305 /**
1306 * Get the current DB name
1307 */
1308 function getDBname() {
1309 return $this->mDBname;
1310 }
1311
1312 /**
1313 * Get the server hostname or IP address
1314 */
1315 function getServer() {
1316 return $this->mServer;
1317 }
1318
1319 /**
1320 * Format a table name ready for use in constructing an SQL query
1321 *
1322 * This does two important things: it quotes the table names to clean them up,
1323 * and it adds a table prefix if only given a table name with no quotes.
1324 *
1325 * All functions of this object which require a table name call this function
1326 * themselves. Pass the canonical name to such functions. This is only needed
1327 * when calling query() directly.
1328 *
1329 * @param $name String: database table name
1330 * @return String: full database name
1331 */
1332 function tableName( $name ) {
1333 global $wgSharedDB, $wgSharedPrefix, $wgSharedTables;
1334 # Skip the entire process when we have a string quoted on both ends.
1335 # Note that we check the end so that we will still quote any use of
1336 # use of `database`.table. But won't break things if someone wants
1337 # to query a database table with a dot in the name.
1338 if ( $name[0] == '`' && substr( $name, -1, 1 ) == '`' ) return $name;
1339
1340 # Lets test for any bits of text that should never show up in a table
1341 # name. Basically anything like JOIN or ON which are actually part of
1342 # SQL queries, but may end up inside of the table value to combine
1343 # sql. Such as how the API is doing.
1344 # Note that we use a whitespace test rather than a \b test to avoid
1345 # any remote case where a word like on may be inside of a table name
1346 # surrounded by symbols which may be considered word breaks.
1347 if( preg_match( '/(^|\s)(DISTINCT|JOIN|ON|AS)(\s|$)/i', $name ) !== 0 ) return $name;
1348
1349 # Split database and table into proper variables.
1350 # We reverse the explode so that database.table and table both output
1351 # the correct table.
1352 $dbDetails = array_reverse( explode( '.', $name, 2 ) );
1353 if( isset( $dbDetails[1] ) ) @list( $table, $database ) = $dbDetails;
1354 else @list( $table ) = $dbDetails;
1355 $prefix = $this->mTablePrefix; # Default prefix
1356
1357 # A database name has been specified in input. Quote the table name
1358 # because we don't want any prefixes added.
1359 if( isset($database) ) $table = ( $table[0] == '`' ? $table : "`{$table}`" );
1360
1361 # Note that we use the long format because php will complain in in_array if
1362 # the input is not an array, and will complain in is_array if it is not set.
1363 if( !isset( $database ) # Don't use shared database if pre selected.
1364 && isset( $wgSharedDB ) # We have a shared database
1365 && $table[0] != '`' # Paranoia check to prevent shared tables listing '`table`'
1366 && isset( $wgSharedTables )
1367 && is_array( $wgSharedTables )
1368 && in_array( $table, $wgSharedTables ) ) { # A shared table is selected
1369 $database = $wgSharedDB;
1370 $prefix = isset( $wgSharedPrefix ) ? $wgSharedPrefix : $prefix;
1371 }
1372
1373 # Quote the $database and $table and apply the prefix if not quoted.
1374 if( isset($database) ) $database = ( $database[0] == '`' ? $database : "`{$database}`" );
1375 $table = ( $table[0] == '`' ? $table : "`{$prefix}{$table}`" );
1376
1377 # Merge our database and table into our final table name.
1378 $tableName = ( isset($database) ? "{$database}.{$table}" : "{$table}" );
1379
1380 # We're finished, return.
1381 return $tableName;
1382 }
1383
1384 /**
1385 * Fetch a number of table names into an array
1386 * This is handy when you need to construct SQL for joins
1387 *
1388 * Example:
1389 * extract($dbr->tableNames('user','watchlist'));
1390 * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1391 * WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1392 */
1393 public function tableNames() {
1394 $inArray = func_get_args();
1395 $retVal = array();
1396 foreach ( $inArray as $name ) {
1397 $retVal[$name] = $this->tableName( $name );
1398 }
1399 return $retVal;
1400 }
1401
1402 /**
1403 * Fetch a number of table names into an zero-indexed numerical array
1404 * This is handy when you need to construct SQL for joins
1405 *
1406 * Example:
1407 * list( $user, $watchlist ) = $dbr->tableNamesN('user','watchlist');
1408 * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1409 * WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1410 */
1411 public function tableNamesN() {
1412 $inArray = func_get_args();
1413 $retVal = array();
1414 foreach ( $inArray as $name ) {
1415 $retVal[] = $this->tableName( $name );
1416 }
1417 return $retVal;
1418 }
1419
1420 /**
1421 * @private
1422 */
1423 function tableNamesWithUseIndexOrJOIN( $tables, $use_index = array(), $join_conds = array() ) {
1424 $ret = array();
1425 $retJOIN = array();
1426 $use_index_safe = is_array($use_index) ? $use_index : array();
1427 $join_conds_safe = is_array($join_conds) ? $join_conds : array();
1428 foreach ( $tables as $table ) {
1429 // Is there a JOIN and INDEX clause for this table?
1430 if ( isset($join_conds_safe[$table]) && isset($use_index_safe[$table]) ) {
1431 $tableClause = $join_conds_safe[$table][0] . ' ' . $this->tableName( $table );
1432 $tableClause .= ' ' . $this->useIndexClause( implode( ',', (array)$use_index_safe[$table] ) );
1433 $tableClause .= ' ON (' . $this->makeList((array)$join_conds_safe[$table][1], LIST_AND) . ')';
1434 $retJOIN[] = $tableClause;
1435 // Is there an INDEX clause?
1436 } else if ( isset($use_index_safe[$table]) ) {
1437 $tableClause = $this->tableName( $table );
1438 $tableClause .= ' ' . $this->useIndexClause( implode( ',', (array)$use_index_safe[$table] ) );
1439 $ret[] = $tableClause;
1440 // Is there a JOIN clause?
1441 } else if ( isset($join_conds_safe[$table]) ) {
1442 $tableClause = $join_conds_safe[$table][0] . ' ' . $this->tableName( $table );
1443 $tableClause .= ' ON (' . $this->makeList((array)$join_conds_safe[$table][1], LIST_AND) . ')';
1444 $retJOIN[] = $tableClause;
1445 } else {
1446 $tableClause = $this->tableName( $table );
1447 $ret[] = $tableClause;
1448 }
1449 }
1450 // We can't separate explicit JOIN clauses with ',', use ' ' for those
1451 $straightJoins = !empty($ret) ? implode( ',', $ret ) : "";
1452 $otherJoins = !empty($retJOIN) ? implode( ' ', $retJOIN ) : "";
1453 // Compile our final table clause
1454 return implode(' ',array($straightJoins,$otherJoins) );
1455 }
1456
1457 /**
1458 * Get the name of an index in a given table
1459 */
1460 function indexName( $index ) {
1461 // Backwards-compatibility hack
1462 $renamed = array(
1463 'ar_usertext_timestamp' => 'usertext_timestamp',
1464 'un_user_id' => 'user_id',
1465 'un_user_ip' => 'user_ip',
1466 );
1467 if( isset( $renamed[$index] ) ) {
1468 return $renamed[$index];
1469 } else {
1470 return $index;
1471 }
1472 }
1473
1474 /**
1475 * Wrapper for addslashes()
1476 * @param $s String: to be slashed.
1477 * @return String: slashed string.
1478 */
1479 abstract function strencode( $s );
1480
1481 /**
1482 * If it's a string, adds quotes and backslashes
1483 * Otherwise returns as-is
1484 */
1485 function addQuotes( $s ) {
1486 if ( $s === null ) {
1487 return 'NULL';
1488 } else {
1489 # This will also quote numeric values. This should be harmless,
1490 # and protects against weird problems that occur when they really
1491 # _are_ strings such as article titles and string->number->string
1492 # conversion is not 1:1.
1493 return "'" . $this->strencode( $s ) . "'";
1494 }
1495 }
1496
1497 /**
1498 * Escape string for safe LIKE usage.
1499 * WARNING: you should almost never use this function directly,
1500 * instead use buildLike() that escapes everything automatically
1501 */
1502 function escapeLike( $s ) {
1503 $s = str_replace( '\\', '\\\\', $s );
1504 $s = $this->strencode( $s );
1505 $s = str_replace( array( '%', '_' ), array( '\%', '\_' ), $s );
1506 return $s;
1507 }
1508
1509 /**
1510 * LIKE statement wrapper, receives a variable-length argument list with parts of pattern to match
1511 * containing either string literals that will be escaped or tokens returned by anyChar() or anyString().
1512 * Alternatively, the function could be provided with an array of aforementioned parameters.
1513 *
1514 * Example: $dbr->buildLike( 'My_page_title/', $dbr->anyString() ) returns a LIKE clause that searches
1515 * for subpages of 'My page title'.
1516 * Alternatively: $pattern = array( 'My_page_title/', $dbr->anyString() ); $query .= $dbr->buildLike( $pattern );
1517 *
1518 * @ return String: fully built LIKE statement
1519 */
1520 function buildLike() {
1521 $params = func_get_args();
1522 if (count($params) > 0 && is_array($params[0])) {
1523 $params = $params[0];
1524 }
1525
1526 $s = '';
1527 foreach( $params as $value) {
1528 if( $value instanceof LikeMatch ) {
1529 $s .= $value->toString();
1530 } else {
1531 $s .= $this->escapeLike( $value );
1532 }
1533 }
1534 return " LIKE '" . $s . "' ";
1535 }
1536
1537 /**
1538 * Returns a token for buildLike() that denotes a '_' to be used in a LIKE query
1539 */
1540 function anyChar() {
1541 return new LikeMatch( '_' );
1542 }
1543
1544 /**
1545 * Returns a token for buildLike() that denotes a '%' to be used in a LIKE query
1546 */
1547 function anyString() {
1548 return new LikeMatch( '%' );
1549 }
1550
1551 /**
1552 * Returns an appropriately quoted sequence value for inserting a new row.
1553 * MySQL has autoincrement fields, so this is just NULL. But the PostgreSQL
1554 * subclass will return an integer, and save the value for insertId()
1555 */
1556 function nextSequenceValue( $seqName ) {
1557 return null;
1558 }
1559
1560 /**
1561 * USE INDEX clause. Unlikely to be useful for anything but MySQL. This
1562 * is only needed because a) MySQL must be as efficient as possible due to
1563 * its use on Wikipedia, and b) MySQL 4.0 is kind of dumb sometimes about
1564 * which index to pick. Anyway, other databases might have different
1565 * indexes on a given table. So don't bother overriding this unless you're
1566 * MySQL.
1567 */
1568 function useIndexClause( $index ) {
1569 return '';
1570 }
1571
1572 /**
1573 * REPLACE query wrapper
1574 * PostgreSQL simulates this with a DELETE followed by INSERT
1575 * $row is the row to insert, an associative array
1576 * $uniqueIndexes is an array of indexes. Each element may be either a
1577 * field name or an array of field names
1578 *
1579 * It may be more efficient to leave off unique indexes which are unlikely to collide.
1580 * However if you do this, you run the risk of encountering errors which wouldn't have
1581 * occurred in MySQL
1582 *
1583 * @todo migrate comment to phodocumentor format
1584 */
1585 function replace( $table, $uniqueIndexes, $rows, $fname = 'Database::replace' ) {
1586 $table = $this->tableName( $table );
1587
1588 # Single row case
1589 if ( !is_array( reset( $rows ) ) ) {
1590 $rows = array( $rows );
1591 }
1592
1593 $sql = "REPLACE INTO $table (" . implode( ',', array_keys( $rows[0] ) ) .') VALUES ';
1594 $first = true;
1595 foreach ( $rows as $row ) {
1596 if ( $first ) {
1597 $first = false;
1598 } else {
1599 $sql .= ',';
1600 }
1601 $sql .= '(' . $this->makeList( $row ) . ')';
1602 }
1603 return $this->query( $sql, $fname );
1604 }
1605
1606 /**
1607 * DELETE where the condition is a join
1608 * MySQL does this with a multi-table DELETE syntax, PostgreSQL does it with sub-selects
1609 *
1610 * For safety, an empty $conds will not delete everything. If you want to delete all rows where the
1611 * join condition matches, set $conds='*'
1612 *
1613 * DO NOT put the join condition in $conds
1614 *
1615 * @param $delTable String: The table to delete from.
1616 * @param $joinTable String: The other table.
1617 * @param $delVar String: The variable to join on, in the first table.
1618 * @param $joinVar String: The variable to join on, in the second table.
1619 * @param $conds Array: Condition array of field names mapped to variables, ANDed together in the WHERE clause
1620 * @param $fname String: Calling function name (use __METHOD__) for logs/profiling
1621 */
1622 function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = 'Database::deleteJoin' ) {
1623 if ( !$conds ) {
1624 throw new DBUnexpectedError( $this, 'Database::deleteJoin() called with empty $conds' );
1625 }
1626
1627 $delTable = $this->tableName( $delTable );
1628 $joinTable = $this->tableName( $joinTable );
1629 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
1630 if ( $conds != '*' ) {
1631 $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
1632 }
1633
1634 return $this->query( $sql, $fname );
1635 }
1636
1637 /**
1638 * Returns the size of a text field, or -1 for "unlimited"
1639 */
1640 function textFieldSize( $table, $field ) {
1641 $table = $this->tableName( $table );
1642 $sql = "SHOW COLUMNS FROM $table LIKE \"$field\";";
1643 $res = $this->query( $sql, 'Database::textFieldSize' );
1644 $row = $this->fetchObject( $res );
1645 $this->freeResult( $res );
1646
1647 $m = array();
1648 if ( preg_match( '/\((.*)\)/', $row->Type, $m ) ) {
1649 $size = $m[1];
1650 } else {
1651 $size = -1;
1652 }
1653 return $size;
1654 }
1655
1656 /**
1657 * A string to insert into queries to show that they're low-priority, like
1658 * MySQL's LOW_PRIORITY. If no such feature exists, return an empty
1659 * string and nothing bad should happen.
1660 *
1661 * @return string Returns the text of the low priority option if it is supported, or a blank string otherwise
1662 */
1663 function lowPriorityOption() {
1664 return '';
1665 }
1666
1667 /**
1668 * DELETE query wrapper
1669 *
1670 * Use $conds == "*" to delete all rows
1671 */
1672 function delete( $table, $conds, $fname = 'Database::delete' ) {
1673 if ( !$conds ) {
1674 throw new DBUnexpectedError( $this, 'Database::delete() called with no conditions' );
1675 }
1676 $table = $this->tableName( $table );
1677 $sql = "DELETE FROM $table";
1678 if ( $conds != '*' ) {
1679 $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1680 }
1681 return $this->query( $sql, $fname );
1682 }
1683
1684 /**
1685 * INSERT SELECT wrapper
1686 * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
1687 * Source items may be literals rather than field names, but strings should be quoted with Database::addQuotes()
1688 * $conds may be "*" to copy the whole table
1689 * srcTable may be an array of tables.
1690 */
1691 function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'Database::insertSelect',
1692 $insertOptions = array(), $selectOptions = array() )
1693 {
1694 $destTable = $this->tableName( $destTable );
1695 if ( is_array( $insertOptions ) ) {
1696 $insertOptions = implode( ' ', $insertOptions );
1697 }
1698 if( !is_array( $selectOptions ) ) {
1699 $selectOptions = array( $selectOptions );
1700 }
1701 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
1702 if( is_array( $srcTable ) ) {
1703 $srcTable = implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
1704 } else {
1705 $srcTable = $this->tableName( $srcTable );
1706 }
1707 $sql = "INSERT $insertOptions INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
1708 " SELECT $startOpts " . implode( ',', $varMap ) .
1709 " FROM $srcTable $useIndex ";
1710 if ( $conds != '*' ) {
1711 $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1712 }
1713 $sql .= " $tailOpts";
1714 return $this->query( $sql, $fname );
1715 }
1716
1717 /**
1718 * Construct a LIMIT query with optional offset. This is used for query
1719 * pages. The SQL should be adjusted so that only the first $limit rows
1720 * are returned. If $offset is provided as well, then the first $offset
1721 * rows should be discarded, and the next $limit rows should be returned.
1722 * If the result of the query is not ordered, then the rows to be returned
1723 * are theoretically arbitrary.
1724 *
1725 * $sql is expected to be a SELECT, if that makes a difference. For
1726 * UPDATE, limitResultForUpdate should be used.
1727 *
1728 * The version provided by default works in MySQL and SQLite. It will very
1729 * likely need to be overridden for most other DBMSes.
1730 *
1731 * @param $sql String: SQL query we will append the limit too
1732 * @param $limit Integer: the SQL limit
1733 * @param $offset Integer the SQL offset (default false)
1734 */
1735 function limitResult( $sql, $limit, $offset=false ) {
1736 if( !is_numeric( $limit ) ) {
1737 throw new DBUnexpectedError( $this, "Invalid non-numeric limit passed to limitResult()\n" );
1738 }
1739 return "$sql LIMIT "
1740 . ( (is_numeric($offset) && $offset != 0) ? "{$offset}," : "" )
1741 . "{$limit} ";
1742 }
1743 function limitResultForUpdate( $sql, $num ) {
1744 return $this->limitResult( $sql, $num, 0 );
1745 }
1746
1747 /**
1748 * Returns true if current database backend supports ORDER BY or LIMIT for separate subqueries
1749 * within the UNION construct.
1750 * @return Boolean
1751 */
1752 function unionSupportsOrderAndLimit() {
1753 return true; // True for almost every DB supported
1754 }
1755
1756 /**
1757 * Construct a UNION query
1758 * This is used for providing overload point for other DB abstractions
1759 * not compatible with the MySQL syntax.
1760 * @param $sqls Array: SQL statements to combine
1761 * @param $all Boolean: use UNION ALL
1762 * @return String: SQL fragment
1763 */
1764 function unionQueries($sqls, $all) {
1765 $glue = $all ? ') UNION ALL (' : ') UNION (';
1766 return '('.implode( $glue, $sqls ) . ')';
1767 }
1768
1769 /**
1770 * Returns an SQL expression for a simple conditional. This doesn't need
1771 * to be overridden unless CASE isn't supported in your DBMS.
1772 *
1773 * @param $cond String: SQL expression which will result in a boolean value
1774 * @param $trueVal String: SQL expression to return if true
1775 * @param $falseVal String: SQL expression to return if false
1776 * @return String: SQL fragment
1777 */
1778 function conditional( $cond, $trueVal, $falseVal ) {
1779 return " (CASE WHEN $cond THEN $trueVal ELSE $falseVal END) ";
1780 }
1781
1782 /**
1783 * Returns a comand for str_replace function in SQL query.
1784 * Uses REPLACE() in MySQL
1785 *
1786 * @param $orig String: column to modify
1787 * @param $old String: column to seek
1788 * @param $new String: column to replace with
1789 */
1790 function strreplace( $orig, $old, $new ) {
1791 return "REPLACE({$orig}, {$old}, {$new})";
1792 }
1793
1794 /**
1795 * Determines if the last failure was due to a deadlock
1796 * STUB
1797 */
1798 function wasDeadlock() {
1799 return false;
1800 }
1801
1802 /**
1803 * Determines if the last query error was something that should be dealt
1804 * with by pinging the connection and reissuing the query.
1805 * STUB
1806 */
1807 function wasErrorReissuable() {
1808 return false;
1809 }
1810
1811 /**
1812 * Determines if the last failure was due to the database being read-only.
1813 * STUB
1814 */
1815 function wasReadOnlyError() {
1816 return false;
1817 }
1818
1819 /**
1820 * Perform a deadlock-prone transaction.
1821 *
1822 * This function invokes a callback function to perform a set of write
1823 * queries. If a deadlock occurs during the processing, the transaction
1824 * will be rolled back and the callback function will be called again.
1825 *
1826 * Usage:
1827 * $dbw->deadlockLoop( callback, ... );
1828 *
1829 * Extra arguments are passed through to the specified callback function.
1830 *
1831 * Returns whatever the callback function returned on its successful,
1832 * iteration, or false on error, for example if the retry limit was
1833 * reached.
1834 */
1835 function deadlockLoop() {
1836 $myFname = 'Database::deadlockLoop';
1837
1838 $this->begin();
1839 $args = func_get_args();
1840 $function = array_shift( $args );
1841 $oldIgnore = $this->ignoreErrors( true );
1842 $tries = DEADLOCK_TRIES;
1843 if ( is_array( $function ) ) {
1844 $fname = $function[0];
1845 } else {
1846 $fname = $function;
1847 }
1848 do {
1849 $retVal = call_user_func_array( $function, $args );
1850 $error = $this->lastError();
1851 $errno = $this->lastErrno();
1852 $sql = $this->lastQuery();
1853
1854 if ( $errno ) {
1855 if ( $this->wasDeadlock() ) {
1856 # Retry
1857 usleep( mt_rand( DEADLOCK_DELAY_MIN, DEADLOCK_DELAY_MAX ) );
1858 } else {
1859 $this->reportQueryError( $error, $errno, $sql, $fname );
1860 }
1861 }
1862 } while( $this->wasDeadlock() && --$tries > 0 );
1863 $this->ignoreErrors( $oldIgnore );
1864 if ( $tries <= 0 ) {
1865 $this->query( 'ROLLBACK', $myFname );
1866 $this->reportQueryError( $error, $errno, $sql, $fname );
1867 return false;
1868 } else {
1869 $this->query( 'COMMIT', $myFname );
1870 return $retVal;
1871 }
1872 }
1873
1874 /**
1875 * Do a SELECT MASTER_POS_WAIT()
1876 *
1877 * @param $pos MySQLMasterPos object
1878 * @param $timeout Integer: the maximum number of seconds to wait for synchronisation
1879 */
1880 function masterPosWait( MySQLMasterPos $pos, $timeout ) {
1881 $fname = 'Database::masterPosWait';
1882 wfProfileIn( $fname );
1883
1884 # Commit any open transactions
1885 if ( $this->mTrxLevel ) {
1886 $this->commit();
1887 }
1888
1889 if ( !is_null( $this->mFakeSlaveLag ) ) {
1890 $wait = intval( ( $pos->pos - microtime(true) + $this->mFakeSlaveLag ) * 1e6 );
1891 if ( $wait > $timeout * 1e6 ) {
1892 wfDebug( "Fake slave timed out waiting for $pos ($wait us)\n" );
1893 wfProfileOut( $fname );
1894 return -1;
1895 } elseif ( $wait > 0 ) {
1896 wfDebug( "Fake slave waiting $wait us\n" );
1897 usleep( $wait );
1898 wfProfileOut( $fname );
1899 return 1;
1900 } else {
1901 wfDebug( "Fake slave up to date ($wait us)\n" );
1902 wfProfileOut( $fname );
1903 return 0;
1904 }
1905 }
1906
1907 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
1908 $encFile = $this->addQuotes( $pos->file );
1909 $encPos = intval( $pos->pos );
1910 $sql = "SELECT MASTER_POS_WAIT($encFile, $encPos, $timeout)";
1911 $res = $this->doQuery( $sql );
1912 if ( $res && $row = $this->fetchRow( $res ) ) {
1913 $this->freeResult( $res );
1914 wfProfileOut( $fname );
1915 return $row[0];
1916 } else {
1917 wfProfileOut( $fname );
1918 return false;
1919 }
1920 }
1921
1922 /**
1923 * Get the position of the master from SHOW SLAVE STATUS
1924 */
1925 function getSlavePos() {
1926 if ( !is_null( $this->mFakeSlaveLag ) ) {
1927 $pos = new MySQLMasterPos( 'fake', microtime(true) - $this->mFakeSlaveLag );
1928 wfDebug( __METHOD__.": fake slave pos = $pos\n" );
1929 return $pos;
1930 }
1931 $res = $this->query( 'SHOW SLAVE STATUS', 'Database::getSlavePos' );
1932 $row = $this->fetchObject( $res );
1933 if ( $row ) {
1934 $pos = isset($row->Exec_master_log_pos) ? $row->Exec_master_log_pos : $row->Exec_Master_Log_Pos;
1935 return new MySQLMasterPos( $row->Relay_Master_Log_File, $pos );
1936 } else {
1937 return false;
1938 }
1939 }
1940
1941 /**
1942 * Get the position of the master from SHOW MASTER STATUS
1943 */
1944 function getMasterPos() {
1945 if ( $this->mFakeMaster ) {
1946 return new MySQLMasterPos( 'fake', microtime( true ) );
1947 }
1948 $res = $this->query( 'SHOW MASTER STATUS', 'Database::getMasterPos' );
1949 $row = $this->fetchObject( $res );
1950 if ( $row ) {
1951 return new MySQLMasterPos( $row->File, $row->Position );
1952 } else {
1953 return false;
1954 }
1955 }
1956
1957 /**
1958 * Begin a transaction, committing any previously open transaction
1959 */
1960 function begin( $fname = 'Database::begin' ) {
1961 $this->query( 'BEGIN', $fname );
1962 $this->mTrxLevel = 1;
1963 }
1964
1965 /**
1966 * End a transaction
1967 */
1968 function commit( $fname = 'Database::commit' ) {
1969 $this->query( 'COMMIT', $fname );
1970 $this->mTrxLevel = 0;
1971 }
1972
1973 /**
1974 * Rollback a transaction.
1975 * No-op on non-transactional databases.
1976 */
1977 function rollback( $fname = 'Database::rollback' ) {
1978 $this->query( 'ROLLBACK', $fname, true );
1979 $this->mTrxLevel = 0;
1980 }
1981
1982 /**
1983 * Begin a transaction, committing any previously open transaction
1984 * @deprecated use begin()
1985 */
1986 function immediateBegin( $fname = 'Database::immediateBegin' ) {
1987 $this->begin();
1988 }
1989
1990 /**
1991 * Commit transaction, if one is open
1992 * @deprecated use commit()
1993 */
1994 function immediateCommit( $fname = 'Database::immediateCommit' ) {
1995 $this->commit();
1996 }
1997
1998 /**
1999 * Creates a new table with structure copied from existing table
2000 * Note that unlike most database abstraction functions, this function does not
2001 * automatically append database prefix, because it works at a lower
2002 * abstraction level.
2003 *
2004 * @param $oldName String: name of table whose structure should be copied
2005 * @param $newName String: name of table to be created
2006 * @param $temporary Boolean: whether the new table should be temporary
2007 * @return Boolean: true if operation was successful
2008 */
2009 function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = 'Database::duplicateTableStructure' ) {
2010 throw new MWException( 'DatabaseBase::duplicateTableStructure is not implemented in descendant class' );
2011 }
2012
2013 /**
2014 * Return MW-style timestamp used for MySQL schema
2015 */
2016 function timestamp( $ts=0 ) {
2017 return wfTimestamp(TS_MW,$ts);
2018 }
2019
2020 /**
2021 * Local database timestamp format or null
2022 */
2023 function timestampOrNull( $ts = null ) {
2024 if( is_null( $ts ) ) {
2025 return null;
2026 } else {
2027 return $this->timestamp( $ts );
2028 }
2029 }
2030
2031 /**
2032 * @todo document
2033 */
2034 function resultObject( $result ) {
2035 if( empty( $result ) ) {
2036 return false;
2037 } elseif ( $result instanceof ResultWrapper ) {
2038 return $result;
2039 } elseif ( $result === true ) {
2040 // Successful write query
2041 return $result;
2042 } else {
2043 return new ResultWrapper( $this, $result );
2044 }
2045 }
2046
2047 /**
2048 * Return aggregated value alias
2049 */
2050 function aggregateValue ($valuedata,$valuename='value') {
2051 return $valuename;
2052 }
2053
2054 /**
2055 * Returns a wikitext link to the DB's website, e.g.,
2056 * return "[http://www.mysql.com/ MySQL]";
2057 * Should at least contain plain text, if for some reason
2058 * your database has no website.
2059 *
2060 * @return String: wikitext of a link to the server software's web site
2061 */
2062 abstract function getSoftwareLink();
2063
2064 /**
2065 * A string describing the current software version, like from
2066 * mysql_get_server_info(). Will be listed on Special:Version, etc.
2067 *
2068 * @return String: Version information from the database
2069 */
2070 abstract function getServerVersion();
2071
2072 /**
2073 * Ping the server and try to reconnect if it there is no connection
2074 *
2075 * @return bool Success or failure
2076 */
2077 function ping() {
2078 # Stub. Not essential to override.
2079 return true;
2080 }
2081
2082 /**
2083 * Get slave lag.
2084 * At the moment, this will only work if the DB user has the PROCESS privilege
2085 */
2086 function getLag() {
2087 if ( !is_null( $this->mFakeSlaveLag ) ) {
2088 wfDebug( "getLag: fake slave lagged {$this->mFakeSlaveLag} seconds\n" );
2089 return $this->mFakeSlaveLag;
2090 }
2091 $res = $this->query( 'SHOW PROCESSLIST', __METHOD__ );
2092 # Find slave SQL thread
2093 while ( $row = $this->fetchObject( $res ) ) {
2094 /* This should work for most situations - when default db
2095 * for thread is not specified, it had no events executed,
2096 * and therefore it doesn't know yet how lagged it is.
2097 *
2098 * Relay log I/O thread does not select databases.
2099 */
2100 if ( $row->User == 'system user' &&
2101 $row->State != 'Waiting for master to send event' &&
2102 $row->State != 'Connecting to master' &&
2103 $row->State != 'Queueing master event to the relay log' &&
2104 $row->State != 'Waiting for master update' &&
2105 $row->State != 'Requesting binlog dump' &&
2106 $row->State != 'Waiting to reconnect after a failed master event read' &&
2107 $row->State != 'Reconnecting after a failed master event read' &&
2108 $row->State != 'Registering slave on master'
2109 ) {
2110 # This is it, return the time (except -ve)
2111 if ( $row->Time > 0x7fffffff ) {
2112 return false;
2113 } else {
2114 return $row->Time;
2115 }
2116 }
2117 }
2118 return false;
2119 }
2120
2121 /**
2122 * Get status information from SHOW STATUS in an associative array
2123 */
2124 function getStatus($which="%") {
2125 $res = $this->query( "SHOW STATUS LIKE '{$which}'" );
2126 $status = array();
2127 while ( $row = $this->fetchObject( $res ) ) {
2128 $status[$row->Variable_name] = $row->Value;
2129 }
2130 return $status;
2131 }
2132
2133 /**
2134 * Return the maximum number of items allowed in a list, or 0 for unlimited.
2135 */
2136 function maxListLen() {
2137 return 0;
2138 }
2139
2140 function encodeBlob($b) {
2141 return $b;
2142 }
2143
2144 function decodeBlob($b) {
2145 return $b;
2146 }
2147
2148 /**
2149 * Override database's default connection timeout. May be useful for very
2150 * long batch queries such as full-wiki dumps, where a single query reads
2151 * out over hours or days. May or may not be necessary for non-MySQL
2152 * databases. For most purposes, leaving it as a no-op should be fine.
2153 *
2154 * @param $timeout Integer in seconds
2155 */
2156 public function setTimeout( $timeout ) {}
2157
2158 /**
2159 * Read and execute SQL commands from a file.
2160 * Returns true on success, error string or exception on failure (depending on object's error ignore settings)
2161 * @param $filename String: File name to open
2162 * @param $lineCallback Callback: Optional function called before reading each line
2163 * @param $resultCallback Callback: Optional function called for each MySQL result
2164 */
2165 function sourceFile( $filename, $lineCallback = false, $resultCallback = false ) {
2166 $fp = fopen( $filename, 'r' );
2167 if ( false === $fp ) {
2168 throw new MWException( "Could not open \"{$filename}\".\n" );
2169 }
2170 $error = $this->sourceStream( $fp, $lineCallback, $resultCallback );
2171 fclose( $fp );
2172 return $error;
2173 }
2174
2175 /**
2176 * Get the full path of a patch file. Originally based on archive()
2177 * from updaters.inc. Keep in mind this always returns a patch, as
2178 * it fails back to MySQL if no DB-specific patch can be found
2179 *
2180 * @param $patch String The name of the patch, like patch-something.sql
2181 * @return String Full path to patch file
2182 */
2183 public static function patchPath( $patch ) {
2184 global $wgDBtype, $IP;
2185 if ( file_exists( "$IP/maintenance/$wgDBtype/archives/$name" ) ) {
2186 return "$IP/maintenance/$wgDBtype/archives/$name";
2187 } else {
2188 return "$IP/maintenance/archives/$name";
2189 }
2190 }
2191
2192 /**
2193 * Read and execute commands from an open file handle
2194 * Returns true on success, error string or exception on failure (depending on object's error ignore settings)
2195 * @param $fp String: File handle
2196 * @param $lineCallback Callback: Optional function called before reading each line
2197 * @param $resultCallback Callback: Optional function called for each MySQL result
2198 */
2199 function sourceStream( $fp, $lineCallback = false, $resultCallback = false ) {
2200 $cmd = "";
2201 $done = false;
2202 $dollarquote = false;
2203
2204 while ( ! feof( $fp ) ) {
2205 if ( $lineCallback ) {
2206 call_user_func( $lineCallback );
2207 }
2208 $line = trim( fgets( $fp, 1024 ) );
2209 $sl = strlen( $line ) - 1;
2210
2211 if ( $sl < 0 ) { continue; }
2212 if ( '-' == $line{0} && '-' == $line{1} ) { continue; }
2213
2214 ## Allow dollar quoting for function declarations
2215 if (substr($line,0,4) == '$mw$') {
2216 if ($dollarquote) {
2217 $dollarquote = false;
2218 $done = true;
2219 }
2220 else {
2221 $dollarquote = true;
2222 }
2223 }
2224 else if (!$dollarquote) {
2225 if ( ';' == $line{$sl} && ($sl < 2 || ';' != $line{$sl - 1})) {
2226 $done = true;
2227 $line = substr( $line, 0, $sl );
2228 }
2229 }
2230
2231 if ( $cmd != '' ) { $cmd .= ' '; }
2232 $cmd .= "$line\n";
2233
2234 if ( $done ) {
2235 $cmd = str_replace(';;', ";", $cmd);
2236 $cmd = $this->replaceVars( $cmd );
2237 $res = $this->query( $cmd, __METHOD__ );
2238 if ( $resultCallback ) {
2239 call_user_func( $resultCallback, $res, $this );
2240 }
2241
2242 if ( false === $res ) {
2243 $err = $this->lastError();
2244 return "Query \"{$cmd}\" failed with error code \"$err\".\n";
2245 }
2246
2247 $cmd = '';
2248 $done = false;
2249 }
2250 }
2251 return true;
2252 }
2253
2254
2255 /**
2256 * Replace variables in sourced SQL
2257 */
2258 protected function replaceVars( $ins ) {
2259 $varnames = array(
2260 'wgDBserver', 'wgDBname', 'wgDBintlname', 'wgDBuser',
2261 'wgDBpassword', 'wgDBsqluser', 'wgDBsqlpassword',
2262 'wgDBadminuser', 'wgDBadminpassword', 'wgDBTableOptions',
2263 );
2264
2265 // Ordinary variables
2266 foreach ( $varnames as $var ) {
2267 if( isset( $GLOBALS[$var] ) ) {
2268 $val = addslashes( $GLOBALS[$var] ); // FIXME: safety check?
2269 $ins = str_replace( '{$' . $var . '}', $val, $ins );
2270 $ins = str_replace( '/*$' . $var . '*/`', '`' . $val, $ins );
2271 $ins = str_replace( '/*$' . $var . '*/', $val, $ins );
2272 }
2273 }
2274
2275 // Table prefixes
2276 $ins = preg_replace_callback( '!/\*(?:\$wgDBprefix|_)\*/([a-zA-Z_0-9]*)!',
2277 array( $this, 'tableNameCallback' ), $ins );
2278
2279 // Index names
2280 $ins = preg_replace_callback( '!/\*i\*/([a-zA-Z_0-9]*)!',
2281 array( $this, 'indexNameCallback' ), $ins );
2282 return $ins;
2283 }
2284
2285 /**
2286 * Table name callback
2287 * @private
2288 */
2289 protected function tableNameCallback( $matches ) {
2290 return $this->tableName( $matches[1] );
2291 }
2292
2293 /**
2294 * Index name callback
2295 */
2296 protected function indexNameCallback( $matches ) {
2297 return $this->indexName( $matches[1] );
2298 }
2299
2300 /**
2301 * Build a concatenation list to feed into a SQL query
2302 * @param $stringList Array: list of raw SQL expressions; caller is responsible for any quoting
2303 * @return String
2304 */
2305 function buildConcat( $stringList ) {
2306 return 'CONCAT(' . implode( ',', $stringList ) . ')';
2307 }
2308
2309 /**
2310 * Acquire a named lock
2311 *
2312 * Abstracted from Filestore::lock() so child classes can implement for
2313 * their own needs.
2314 *
2315 * @param $lockName String: Name of lock to aquire
2316 * @param $method String: Name of method calling us
2317 * @return bool
2318 */
2319 public function lock( $lockName, $method, $timeout = 5 ) {
2320 return true;
2321 }
2322
2323 /**
2324 * Release a lock.
2325 *
2326 * @param $lockName String: Name of lock to release
2327 * @param $method String: Name of method calling us
2328 *
2329 * FROM MYSQL DOCS: http://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html#function_release-lock
2330 * @return Returns 1 if the lock was released, 0 if the lock was not established
2331 * by this thread (in which case the lock is not released), and NULL if the named
2332 * lock did not exist
2333 */
2334 public function unlock( $lockName, $method ) {
2335 return true;
2336 }
2337
2338 /**
2339 * Lock specific tables
2340 *
2341 * @param $read Array of tables to lock for read access
2342 * @param $write Array of tables to lock for write access
2343 * @param $method String name of caller
2344 * @param $lowPriority bool Whether to indicate writes to be LOW PRIORITY
2345 */
2346 public function lockTables( $read, $write, $method, $lowPriority = true ) {
2347 return true;
2348 }
2349
2350 /**
2351 * Unlock specific tables
2352 *
2353 * @param $method String the caller
2354 */
2355 public function unlockTables( $method ) {
2356 return true;
2357 }
2358
2359 /**
2360 * Get search engine class. All subclasses of this
2361 * need to implement this if they wish to use searching.
2362 *
2363 * @return String
2364 */
2365 public function getSearchEngine() {
2366 return "SearchMySQL";
2367 }
2368
2369 /**
2370 * Allow or deny "big selects" for this session only. This is done by setting
2371 * the sql_big_selects session variable.
2372 *
2373 * This is a MySQL-specific feature.
2374 *
2375 * @param mixed $value true for allow, false for deny, or "default" to restore the initial value
2376 */
2377 public function setBigSelects( $value = true ) {
2378 // no-op
2379 }
2380 }
2381
2382
2383 /******************************************************************************
2384 * Utility classes
2385 *****************************************************************************/
2386
2387 /**
2388 * Utility class.
2389 * @ingroup Database
2390 */
2391 class DBObject {
2392 public $mData;
2393
2394 function DBObject($data) {
2395 $this->mData = $data;
2396 }
2397
2398 function isLOB() {
2399 return false;
2400 }
2401
2402 function data() {
2403 return $this->mData;
2404 }
2405 }
2406
2407 /**
2408 * Utility class
2409 * @ingroup Database
2410 *
2411 * This allows us to distinguish a blob from a normal string and an array of strings
2412 */
2413 class Blob {
2414 private $mData;
2415 function __construct($data) {
2416 $this->mData = $data;
2417 }
2418 function fetch() {
2419 return $this->mData;
2420 }
2421 }
2422
2423 /**
2424 * Utility class.
2425 * @ingroup Database
2426 */
2427 class MySQLField {
2428 private $name, $tablename, $default, $max_length, $nullable,
2429 $is_pk, $is_unique, $is_multiple, $is_key, $type;
2430 function __construct ($info) {
2431 $this->name = $info->name;
2432 $this->tablename = $info->table;
2433 $this->default = $info->def;
2434 $this->max_length = $info->max_length;
2435 $this->nullable = !$info->not_null;
2436 $this->is_pk = $info->primary_key;
2437 $this->is_unique = $info->unique_key;
2438 $this->is_multiple = $info->multiple_key;
2439 $this->is_key = ($this->is_pk || $this->is_unique || $this->is_multiple);
2440 $this->type = $info->type;
2441 }
2442
2443 function name() {
2444 return $this->name;
2445 }
2446
2447 function tableName() {
2448 return $this->tableName;
2449 }
2450
2451 function defaultValue() {
2452 return $this->default;
2453 }
2454
2455 function maxLength() {
2456 return $this->max_length;
2457 }
2458
2459 function nullable() {
2460 return $this->nullable;
2461 }
2462
2463 function isKey() {
2464 return $this->is_key;
2465 }
2466
2467 function isMultipleKey() {
2468 return $this->is_multiple;
2469 }
2470
2471 function type() {
2472 return $this->type;
2473 }
2474 }
2475
2476 /******************************************************************************
2477 * Error classes
2478 *****************************************************************************/
2479
2480 /**
2481 * Database error base class
2482 * @ingroup Database
2483 */
2484 class DBError extends MWException {
2485 public $db;
2486
2487 /**
2488 * Construct a database error
2489 * @param $db Database object which threw the error
2490 * @param $error A simple error message to be used for debugging
2491 */
2492 function __construct( DatabaseBase &$db, $error ) {
2493 $this->db =& $db;
2494 parent::__construct( $error );
2495 }
2496
2497 function getText() {
2498 global $wgShowDBErrorBacktrace;
2499 $s = $this->getMessage() . "\n";
2500 if ( $wgShowDBErrorBacktrace ) {
2501 $s .= "Backtrace:\n" . $this->getTraceAsString() . "\n";
2502 }
2503 return $s;
2504 }
2505 }
2506
2507 /**
2508 * @ingroup Database
2509 */
2510 class DBConnectionError extends DBError {
2511 public $error;
2512
2513 function __construct( DatabaseBase &$db, $error = 'unknown error' ) {
2514 $msg = 'DB connection error';
2515 if ( trim( $error ) != '' ) {
2516 $msg .= ": $error";
2517 }
2518 $this->error = $error;
2519 parent::__construct( $db, $msg );
2520 }
2521
2522 function useOutputPage() {
2523 // Not likely to work
2524 return false;
2525 }
2526
2527 function useMessageCache() {
2528 // Not likely to work
2529 return false;
2530 }
2531
2532 function getLogMessage() {
2533 # Don't send to the exception log
2534 return false;
2535 }
2536
2537 function getPageTitle() {
2538 global $wgSitename, $wgLang;
2539 $header = "$wgSitename has a problem";
2540 if ( $wgLang instanceof Language ) {
2541 $header = htmlspecialchars( $wgLang->getMessage( 'dberr-header' ) );
2542 }
2543
2544 return $header;
2545 }
2546
2547 function getHTML() {
2548 global $wgLang, $wgMessageCache, $wgUseFileCache, $wgShowDBErrorBacktrace;
2549
2550 $sorry = 'Sorry! This site is experiencing technical difficulties.';
2551 $again = 'Try waiting a few minutes and reloading.';
2552 $info = '(Can\'t contact the database server: $1)';
2553
2554 if ( $wgLang instanceof Language ) {
2555 $sorry = htmlspecialchars( $wgLang->getMessage( 'dberr-problems' ) );
2556 $again = htmlspecialchars( $wgLang->getMessage( 'dberr-again' ) );
2557 $info = htmlspecialchars( $wgLang->getMessage( 'dberr-info' ) );
2558 }
2559
2560 # No database access
2561 if ( is_object( $wgMessageCache ) ) {
2562 $wgMessageCache->disable();
2563 }
2564
2565 if ( trim( $this->error ) == '' ) {
2566 $this->error = $this->db->getProperty('mServer');
2567 }
2568
2569 $noconnect = "<p><strong>$sorry</strong><br />$again</p><p><small>$info</small></p>";
2570 $text = str_replace( '$1', $this->error, $noconnect );
2571
2572 if ( $wgShowDBErrorBacktrace ) {
2573 $text .= '<p>Backtrace:</p><p>' . nl2br( htmlspecialchars( $this->getTraceAsString() ) );
2574 }
2575
2576 $extra = $this->searchForm();
2577
2578 if( $wgUseFileCache ) {
2579 try {
2580 $cache = $this->fileCachedPage();
2581 # Cached version on file system?
2582 if( $cache !== null ) {
2583 # Hack: extend the body for error messages
2584 $cache = str_replace( array('</html>','</body>'), '', $cache );
2585 # Add cache notice...
2586 $cachederror = "This is a cached copy of the requested page, and may not be up to date. ";
2587 # Localize it if possible...
2588 if( $wgLang instanceof Language ) {
2589 $cachederror = htmlspecialchars( $wgLang->getMessage( 'dberr-cachederror' ) );
2590 }
2591 $warning = "<div style='color:red;font-size:150%;font-weight:bold;'>$cachederror</div>";
2592 # Output cached page with notices on bottom and re-close body
2593 return "{$cache}{$warning}<hr />$text<hr />$extra</body></html>";
2594 }
2595 } catch( MWException $e ) {
2596 // Do nothing, just use the default page
2597 }
2598 }
2599 # Headers needed here - output is just the error message
2600 return $this->htmlHeader()."$text<hr />$extra".$this->htmlFooter();
2601 }
2602
2603 function searchForm() {
2604 global $wgSitename, $wgServer, $wgLang, $wgInputEncoding;
2605 $usegoogle = "You can try searching via Google in the meantime.";
2606 $outofdate = "Note that their indexes of our content may be out of date.";
2607 $googlesearch = "Search";
2608
2609 if ( $wgLang instanceof Language ) {
2610 $usegoogle = htmlspecialchars( $wgLang->getMessage( 'dberr-usegoogle' ) );
2611 $outofdate = htmlspecialchars( $wgLang->getMessage( 'dberr-outofdate' ) );
2612 $googlesearch = htmlspecialchars( $wgLang->getMessage( 'searchbutton' ) );
2613 }
2614
2615 $search = htmlspecialchars(@$_REQUEST['search']);
2616
2617 $trygoogle = <<<EOT
2618 <div style="margin: 1.5em">$usegoogle<br />
2619 <small>$outofdate</small></div>
2620 <!-- SiteSearch Google -->
2621 <form method="get" action="http://www.google.com/search" id="googlesearch">
2622 <input type="hidden" name="domains" value="$wgServer" />
2623 <input type="hidden" name="num" value="50" />
2624 <input type="hidden" name="ie" value="$wgInputEncoding" />
2625 <input type="hidden" name="oe" value="$wgInputEncoding" />
2626
2627 <input type="text" name="q" size="31" maxlength="255" value="$search" />
2628 <input type="submit" name="btnG" value="$googlesearch" />
2629 <div>
2630 <input type="radio" name="sitesearch" id="gwiki" value="$wgServer" checked="checked" /><label for="gwiki">$wgSitename</label>
2631 <input type="radio" name="sitesearch" id="gWWW" value="" /><label for="gWWW">WWW</label>
2632 </div>
2633 </form>
2634 <!-- SiteSearch Google -->
2635 EOT;
2636 return $trygoogle;
2637 }
2638
2639 function fileCachedPage() {
2640 global $wgTitle, $title, $wgLang, $wgOut;
2641 if( $wgOut->isDisabled() ) return; // Done already?
2642 $mainpage = 'Main Page';
2643 if ( $wgLang instanceof Language ) {
2644 $mainpage = htmlspecialchars( $wgLang->getMessage( 'mainpage' ) );
2645 }
2646
2647 if( $wgTitle ) {
2648 $t =& $wgTitle;
2649 } elseif( $title ) {
2650 $t = Title::newFromURL( $title );
2651 } else {
2652 $t = Title::newFromText( $mainpage );
2653 }
2654
2655 $cache = new HTMLFileCache( $t );
2656 if( $cache->isFileCached() ) {
2657 return $cache->fetchPageText();
2658 } else {
2659 return '';
2660 }
2661 }
2662
2663 function htmlBodyOnly() {
2664 return true;
2665 }
2666
2667 }
2668
2669 /**
2670 * @ingroup Database
2671 */
2672 class DBQueryError extends DBError {
2673 public $error, $errno, $sql, $fname;
2674
2675 function __construct( DatabaseBase &$db, $error, $errno, $sql, $fname ) {
2676 $message = "A database error has occurred\n" .
2677 "Query: $sql\n" .
2678 "Function: $fname\n" .
2679 "Error: $errno $error\n";
2680
2681 parent::__construct( $db, $message );
2682 $this->error = $error;
2683 $this->errno = $errno;
2684 $this->sql = $sql;
2685 $this->fname = $fname;
2686 }
2687
2688 function getText() {
2689 global $wgShowDBErrorBacktrace;
2690 if ( $this->useMessageCache() ) {
2691 $s = wfMsg( 'dberrortextcl', htmlspecialchars( $this->getSQL() ),
2692 htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) ) . "\n";
2693 if ( $wgShowDBErrorBacktrace ) {
2694 $s .= "Backtrace:\n" . $this->getTraceAsString() . "\n";
2695 }
2696 return $s;
2697 } else {
2698 return parent::getText();
2699 }
2700 }
2701
2702 function getSQL() {
2703 global $wgShowSQLErrors;
2704 if( !$wgShowSQLErrors ) {
2705 return $this->msg( 'sqlhidden', 'SQL hidden' );
2706 } else {
2707 return $this->sql;
2708 }
2709 }
2710
2711 function getLogMessage() {
2712 # Don't send to the exception log
2713 return false;
2714 }
2715
2716 function getPageTitle() {
2717 return $this->msg( 'databaseerror', 'Database error' );
2718 }
2719
2720 function getHTML() {
2721 global $wgShowDBErrorBacktrace;
2722 if ( $this->useMessageCache() ) {
2723 $s = wfMsgNoDB( 'dberrortext', htmlspecialchars( $this->getSQL() ),
2724 htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) );
2725 } else {
2726 $s = nl2br( htmlspecialchars( $this->getMessage() ) );
2727 }
2728 if ( $wgShowDBErrorBacktrace ) {
2729 $s .= '<p>Backtrace:</p><p>' . nl2br( htmlspecialchars( $this->getTraceAsString() ) );
2730 }
2731 return $s;
2732 }
2733 }
2734
2735 /**
2736 * @ingroup Database
2737 */
2738 class DBUnexpectedError extends DBError {}
2739
2740
2741 /**
2742 * Result wrapper for grabbing data queried by someone else
2743 * @ingroup Database
2744 */
2745 class ResultWrapper implements Iterator {
2746 var $db, $result, $pos = 0, $currentRow = null;
2747
2748 /**
2749 * Create a new result object from a result resource and a Database object
2750 */
2751 function ResultWrapper( $database, $result ) {
2752 $this->db = $database;
2753 if ( $result instanceof ResultWrapper ) {
2754 $this->result = $result->result;
2755 } else {
2756 $this->result = $result;
2757 }
2758 }
2759
2760 /**
2761 * Get the number of rows in a result object
2762 */
2763 function numRows() {
2764 return $this->db->numRows( $this );
2765 }
2766
2767 /**
2768 * Fetch the next row from the given result object, in object form.
2769 * Fields can be retrieved with $row->fieldname, with fields acting like
2770 * member variables.
2771 *
2772 * @param $res SQL result object as returned from Database::query(), etc.
2773 * @return MySQL row object
2774 * @throws DBUnexpectedError Thrown if the database returns an error
2775 */
2776 function fetchObject() {
2777 return $this->db->fetchObject( $this );
2778 }
2779
2780 /**
2781 * Fetch the next row from the given result object, in associative array
2782 * form. Fields are retrieved with $row['fieldname'].
2783 *
2784 * @param $res SQL result object as returned from Database::query(), etc.
2785 * @return MySQL row object
2786 * @throws DBUnexpectedError Thrown if the database returns an error
2787 */
2788 function fetchRow() {
2789 return $this->db->fetchRow( $this );
2790 }
2791
2792 /**
2793 * Free a result object
2794 */
2795 function free() {
2796 $this->db->freeResult( $this );
2797 unset( $this->result );
2798 unset( $this->db );
2799 }
2800
2801 /**
2802 * Change the position of the cursor in a result object
2803 * See mysql_data_seek()
2804 */
2805 function seek( $row ) {
2806 $this->db->dataSeek( $this, $row );
2807 }
2808
2809 /*********************
2810 * Iterator functions
2811 * Note that using these in combination with the non-iterator functions
2812 * above may cause rows to be skipped or repeated.
2813 */
2814
2815 function rewind() {
2816 if ($this->numRows()) {
2817 $this->db->dataSeek($this, 0);
2818 }
2819 $this->pos = 0;
2820 $this->currentRow = null;
2821 }
2822
2823 function current() {
2824 if ( is_null( $this->currentRow ) ) {
2825 $this->next();
2826 }
2827 return $this->currentRow;
2828 }
2829
2830 function key() {
2831 return $this->pos;
2832 }
2833
2834 function next() {
2835 $this->pos++;
2836 $this->currentRow = $this->fetchObject();
2837 return $this->currentRow;
2838 }
2839
2840 function valid() {
2841 return $this->current() !== false;
2842 }
2843 }
2844
2845 /**
2846 * Used by DatabaseBase::buildLike() to represent characters that have special meaning in SQL LIKE clauses
2847 * and thus need no escaping. Don't instantiate it manually, use Database::anyChar() and anyString() instead.
2848 */
2849 class LikeMatch {
2850 private $str;
2851
2852 public function __construct( $s ) {
2853 $this->str = $s;
2854 }
2855
2856 public function toString() {
2857 return $this->str;
2858 }
2859 }
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