includes/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 class Database {
  23
  24 #------------------------------------------------------------------------------
  25 # Variables
  26 #------------------------------------------------------------------------------
  27
  28         protected $mLastQuery = '';
  29         protected $mPHPError = false;
  30
  31         protected $mServer, $mUser, $mPassword, $mConn = null, $mDBname;
  32         protected $mOut, $mOpened = false;
  33
  34         protected $mFailFunction;
  35         protected $mTablePrefix;
  36         protected $mFlags;
  37         protected $mTrxLevel = 0;
  38         protected $mErrorCount = 0;
  39         protected $mLBInfo = array();
  40         protected $mFakeSlaveLag = null, $mFakeMaster = false;
  41
  42 #------------------------------------------------------------------------------
  43 # Accessors
  44 #------------------------------------------------------------------------------
  45         # These optionally set a variable and return the previous state
  46
  47         /**
  48          * Fail function, takes a Database as a parameter
  49          * Set to false for default, 1 for ignore errors
  50          */
  51         function failFunction( $function = NULL ) {
  52                 return wfSetVar( $this->mFailFunction, $function );
  53         }
  54
  55         /**
  56          * Output page, used for reporting errors
  57          * FALSE means discard output
  58          */
  59         function setOutputPage( $out ) {
  60                 $this->mOut = $out;
  61         }
  62
  63         /**
  64          * Boolean, controls output of large amounts of debug information
  65          */
  66         function debug( $debug = NULL ) {
  67                 return wfSetBit( $this->mFlags, DBO_DEBUG, $debug );
  68         }
  69
  70         /**
  71          * Turns buffering of SQL result sets on (true) or off (false).
  72          * Default is "on" and it should not be changed without good reasons.
  73          */
  74         function bufferResults( $buffer = NULL ) {
  75                 if ( is_null( $buffer ) ) {
  76                         return !(bool)( $this->mFlags & DBO_NOBUFFER );
  77                 } else {
  78                         return !wfSetBit( $this->mFlags, DBO_NOBUFFER, !$buffer );
  79                 }
  80         }
  81
  82         /**
  83          * Turns on (false) or off (true) the automatic generation and sending
  84          * of a "we're sorry, but there has been a database error" page on
  85          * database errors. Default is on (false). When turned off, the
  86          * code should use lastErrno() and lastError() to handle the
  87          * situation as appropriate.
  88          */
  89         function ignoreErrors( $ignoreErrors = NULL ) {
  90                 return wfSetBit( $this->mFlags, DBO_IGNORE, $ignoreErrors );
  91         }
  92
  93         /**
  94          * The current depth of nested transactions
  95          * @param $level Integer: , default NULL.
  96          */
  97         function trxLevel( $level = NULL ) {
  98                 return wfSetVar( $this->mTrxLevel, $level );
  99         }
 100
 101         /**
 102          * Number of errors logged, only useful when errors are ignored
 103          */
 104         function errorCount( $count = NULL ) {
 105                 return wfSetVar( $this->mErrorCount, $count );
 106         }
 107
 108         function tablePrefix( $prefix = null ) {
 109                 return wfSetVar( $this->mTablePrefix, $prefix );
 110         }
 111
 112         /**
 113          * Properties passed down from the server info array of the load balancer
 114          */
 115         function getLBInfo( $name = NULL ) {
 116                 if ( is_null( $name ) ) {
 117                         return $this->mLBInfo;
 118                 } else {
 119                         if ( array_key_exists( $name, $this->mLBInfo ) ) {
 120                                 return $this->mLBInfo[$name];
 121                         } else {
 122                                 return NULL;
 123                         }
 124                 }
 125         }
 126
 127         function setLBInfo( $name, $value = NULL ) {
 128                 if ( is_null( $value ) ) {
 129                         $this->mLBInfo = $name;
 130                 } else {
 131                         $this->mLBInfo[$name] = $value;
 132                 }
 133         }
 134
 135         /**
 136          * Set lag time in seconds for a fake slave
 137          */
 138         function setFakeSlaveLag( $lag ) {
 139                 $this->mFakeSlaveLag = $lag;
 140         }
 141
 142         /**
 143          * Make this connection a fake master
 144          */
 145         function setFakeMaster( $enabled = true ) {
 146                 $this->mFakeMaster = $enabled;
 147         }
 148
 149         /**
 150          * Returns true if this database supports (and uses) cascading deletes
 151          */
 152         function cascadingDeletes() {
 153                 return false;
 154         }
 155
 156         /**
 157          * Returns true if this database supports (and uses) triggers (e.g. on the page table)
 158          */
 159         function cleanupTriggers() {
 160                 return false;
 161         }
 162
 163         /**
 164          * Returns true if this database is strict about what can be put into an IP field.
 165          * Specifically, it uses a NULL value instead of an empty string.
 166          */
 167         function strictIPs() {
 168                 return false;
 169         }
 170
 171         /**
 172          * Returns true if this database uses timestamps rather than integers
 173         */
 174         function realTimestamps() {
 175                 return false;
 176         }
 177
 178         /**
 179          * Returns true if this database does an implicit sort when doing GROUP BY
 180          */
 181         function implicitGroupby() {
 182                 return true;
 183         }
 184
 185         /**
 186          * Returns true if this database does an implicit order by when the column has an index
 187          * For example: SELECT page_title FROM page LIMIT 1
 188          */
 189         function implicitOrderby() {
 190                 return true;
 191         }
 192
 193         /**
 194          * Returns true if this database can do a native search on IP columns
 195          * e.g. this works as expected: .. WHERE rc_ip = '127.42.12.102/32';
 196          */
 197         function searchableIPs() {
 198                 return false;
 199         }
 200
 201         /**
 202          * Returns true if this database can use functional indexes
 203          */
 204         function functionalIndexes() {
 205                 return false;
 206         }
 207
 208         /**#@+
 209          * Get function
 210          */
 211         function lastQuery() { return $this->mLastQuery; }
 212         function isOpen() { return $this->mOpened; }
 213         /**#@-*/
 214
 215         function setFlag( $flag ) {
 216                 $this->mFlags |= $flag;
 217         }
 218
 219         function clearFlag( $flag ) {
 220                 $this->mFlags &= ~$flag;
 221         }
 222
 223         function getFlag( $flag ) {
 224                 return !!($this->mFlags & $flag);
 225         }
 226
 227         /**
 228          * General read-only accessor
 229          */
 230         function getProperty( $name ) {
 231                 return $this->$name;
 232         }
 233
 234         function getWikiID() {
 235                 if( $this->mTablePrefix ) {
 236                         return "{$this->mDBname}-{$this->mTablePrefix}";
 237                 } else {
 238                         return $this->mDBname;
 239                 }
 240         }
 241
 242 #------------------------------------------------------------------------------
 243 # Other functions
 244 #------------------------------------------------------------------------------
 245
 246         /**@{{
 247          * Constructor.
 248          * @param string $server database server host
 249          * @param string $user database user name
 250          * @param string $password database user password
 251          * @param string $dbname database name
 252          * @param failFunction
 253          * @param $flags
 254          * @param $tablePrefix String: database table prefixes. By default use the prefix gave in LocalSettings.php
 255          */
 256         function __construct( $server = false, $user = false, $password = false, $dbName = false,
 257                 $failFunction = false, $flags = 0, $tablePrefix = 'get from global' ) {
 258
 259                 global $wgOut, $wgDBprefix, $wgCommandLineMode;
 260                 # Can't get a reference if it hasn't been set yet
 261                 if ( !isset( $wgOut ) ) {
 262                         $wgOut = NULL;
 263                 }
 264                 $this->mOut =& $wgOut;
 265
 266                 $this->mFailFunction = $failFunction;
 267                 $this->mFlags = $flags;
 268
 269                 if ( $this->mFlags & DBO_DEFAULT ) {
 270                         if ( $wgCommandLineMode ) {
 271                                 $this->mFlags &= ~DBO_TRX;
 272                         } else {
 273                                 $this->mFlags |= DBO_TRX;
 274                         }
 275                 }
 276
 277                 /*
 278                 // Faster read-only access
 279                 if ( wfReadOnly() ) {
 280                         $this->mFlags |= DBO_PERSISTENT;
 281                         $this->mFlags &= ~DBO_TRX;
 282                 }*/
 283
 284                 /** Get the default table prefix*/
 285                 if ( $tablePrefix == 'get from global' ) {
 286                         $this->mTablePrefix = $wgDBprefix;
 287                 } else {
 288                         $this->mTablePrefix = $tablePrefix;
 289                 }
 290
 291                 if ( $server ) {
 292                         $this->open( $server, $user, $password, $dbName );
 293                 }
 294         }
 295
 296         /**
 297          * @static
 298          * @param failFunction
 299          * @param $flags
 300          */
 301         static function newFromParams( $server, $user, $password, $dbName, $failFunction = false, $flags = 0 )
 302         {
 303                 return new Database( $server, $user, $password, $dbName, $failFunction, $flags );
 304         }
 305
 306         /**
 307          * Usually aborts on failure
 308          * If the failFunction is set to a non-zero integer, returns success
 309          */
 310         function open( $server, $user, $password, $dbName ) {
 311                 global $wguname, $wgAllDBsAreLocalhost;
 312                 wfProfileIn( __METHOD__ );
 313
 314                 # Test for missing mysql.so
 315                 # First try to load it
 316                 if (!@extension_loaded('mysql')) {
 317                         @dl('mysql.so');
 318                 }
 319
 320                 # Fail now
 321                 # Otherwise we get a suppressed fatal error, which is very hard to track down
 322                 if ( !function_exists( 'mysql_connect' ) ) {
 323                         throw new DBConnectionError( $this, "MySQL functions missing, have you compiled PHP with the --with-mysql option?\n" );
 324                 }
 325
 326                 # Debugging hack -- fake cluster
 327                 if ( $wgAllDBsAreLocalhost ) {
 328                         $realServer = 'localhost';
 329                 } else {
 330                         $realServer = $server;
 331                 }
 332                 $this->close();
 333                 $this->mServer = $server;
 334                 $this->mUser = $user;
 335                 $this->mPassword = $password;
 336                 $this->mDBname = $dbName;
 337
 338                 $success = false;
 339
 340                 wfProfileIn("dbconnect-$server");
 341
 342                 # Try to connect up to three times
 343                 # The kernel's default SYN retransmission period is far too slow for us,
 344                 # so we use a short timeout plus a manual retry.
 345                 $this->mConn = false;
 346                 $max = 3;
 347                 $this->installErrorHandler();
 348                 for ( $i = 0; $i < $max && !$this->mConn; $i++ ) {
 349                         if ( $i > 1 ) {
 350                                 usleep( 1000 );
 351                         }
 352                         if ( $this->mFlags & DBO_PERSISTENT ) {
 353                                 $this->mConn = mysql_pconnect( $realServer, $user, $password );
 354                         } else {
 355                                 # Create a new connection...
 356                                 $this->mConn = mysql_connect( $realServer, $user, $password, true );
 357                         }
 358                         if ($this->mConn === false) {
 359                                 #$iplus = $i + 1;
 360                                 #wfLogDBError("Connect loop error $iplus of $max ($server): " . mysql_errno() . " - " . mysql_error()."\n");
 361                         }
 362                 }
 363                 $phpError = $this->restoreErrorHandler();
 364
 365                 wfProfileOut("dbconnect-$server");
 366
 367                 if ( $dbName != '' ) {
 368                         if ( $this->mConn !== false ) {
 369                                 $success = @/**/mysql_select_db( $dbName, $this->mConn );
 370                                 if ( !$success ) {
 371                                         $error = "Error selecting database $dbName on server {$this->mServer} " .
 372                                                 "from client host {$wguname['nodename']}\n";
 373                                         wfLogDBError(" Error selecting database $dbName on server {$this->mServer} \n");
 374                                         wfDebug( $error );
 375                                 }
 376                         } else {
 377                                 wfDebug( "DB connection error\n" );
 378                                 wfDebug( "Server: $server, User: $user, Password: " .
 379                                         substr( $password, 0, 3 ) . "..., error: " . mysql_error() . "\n" );
 380                                 $success = false;
 381                         }
 382                 } else {
 383                         # Delay USE query
 384                         $success = (bool)$this->mConn;
 385                 }
 386
 387                 if ( $success ) {
 388                         $version = $this->getServerVersion();
 389                         if ( version_compare( $version, '4.1' ) >= 0 ) {
 390                                 // Tell the server we're communicating with it in UTF-8.
 391                                 // This may engage various charset conversions.
 392                                 global $wgDBmysql5;
 393                                 if( $wgDBmysql5 ) {
 394                                         $this->query( 'SET NAMES utf8', __METHOD__ );
 395                                 }
 396                                 // Turn off strict mode
 397                                 $this->query( "SET sql_mode = ''", __METHOD__ );
 398                         }
 399
 400                         // Turn off strict mode if it is on
 401                 } else {
 402                         $this->reportConnectionError( $phpError );
 403                 }
 404
 405                 $this->mOpened = $success;
 406                 wfProfileOut( __METHOD__ );
 407                 return $success;
 408         }
 409         /**@}}*/
 410
 411         protected function installErrorHandler() {
 412                 $this->mPHPError = false;
 413                 set_error_handler( array( $this, 'connectionErrorHandler' ) );
 414         }
 415
 416         protected function restoreErrorHandler() {
 417                 restore_error_handler();
 418                 return $this->mPHPError;
 419         }
 420
 421         protected function connectionErrorHandler( $errno,  $errstr ) {
 422                 $this->mPHPError = $errstr;
 423         }
 424
 425         /**
 426          * Closes a database connection.
 427          * if it is open : commits any open transactions
 428          *
 429          * @return bool operation success. true if already closed.
 430          */
 431         function close()
 432         {
 433                 $this->mOpened = false;
 434                 if ( $this->mConn ) {
 435                         if ( $this->trxLevel() ) {
 436                                 $this->immediateCommit();
 437                         }
 438                         return mysql_close( $this->mConn );
 439                 } else {
 440                         return true;
 441                 }
 442         }
 443
 444         /**
 445          * @param string $error fallback error message, used if none is given by MySQL
 446          */
 447         function reportConnectionError( $error = 'Unknown error' ) {
 448                 $myError = $this->lastError();
 449                 if ( $myError ) {
 450                         $error = $myError;
 451                 }
 452
 453                 if ( $this->mFailFunction ) {
 454                         # Legacy error handling method
 455                         if ( !is_int( $this->mFailFunction ) ) {
 456                                 $ff = $this->mFailFunction;
 457                                 $ff( $this, $error );
 458                         }
 459                 } else {
 460                         # New method
 461                         wfLogDBError( "Connection error: $error\n" );
 462                         throw new DBConnectionError( $this, $error );
 463                 }
 464         }
 465
 466         /**
 467          * Usually aborts on failure.  If errors are explicitly ignored, returns success.
 468          *
 469          * @param  $sql        String: SQL query
 470          * @param  $fname      String: Name of the calling function, for profiling/SHOW PROCESSLIST
 471          *     comment (you can use __METHOD__ or add some extra info)
 472          * @param  $tempIgnore Bool:   Whether to avoid throwing an exception on errors...
 473          *     maybe best to catch the exception instead?
 474          * @return true for a successful write query, ResultWrapper object for a successful read query,
 475          *     or false on failure if $tempIgnore set
 476          * @throws DBQueryError Thrown when the database returns an error of any kind
 477          */
 478         public function query( $sql, $fname = '', $tempIgnore = false ) {
 479                 global $wgProfiler;
 480
 481                 $isMaster = !is_null( $this->getLBInfo( 'master' ) );
 482                 if ( isset( $wgProfiler ) ) {
 483                         # generalizeSQL will probably cut down the query to reasonable
 484                         # logging size most of the time. The substr is really just a sanity check.
 485
 486                         # Who's been wasting my precious column space? -- TS
 487                         #$profName = 'query: ' . $fname . ' ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 488
 489                         if ( $isMaster ) {
 490                                 $queryProf = 'query-m: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 491                                 $totalProf = 'Database::query-master';
 492                         } else {
 493                                 $queryProf = 'query: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 494                                 $totalProf = 'Database::query';
 495                         }
 496                         wfProfileIn( $totalProf );
 497                         wfProfileIn( $queryProf );
 498                 }
 499
 500                 $this->mLastQuery = $sql;
 501
 502                 # Add a comment for easy SHOW PROCESSLIST interpretation
 503                 #if ( $fname ) {
 504                         global $wgUser;
 505                         if ( is_object( $wgUser ) && !($wgUser instanceof StubObject) ) {
 506                                 $userName = $wgUser->getName();
 507                                 if ( mb_strlen( $userName ) > 15 ) {
 508                                         $userName = mb_substr( $userName, 0, 15 ) . '...';
 509                                 }
 510                                 $userName = str_replace( '/', '', $userName );
 511                         } else {
 512                                 $userName = '';
 513                         }
 514                         $commentedSql = preg_replace('/\s/', " /* $fname $userName */ ", $sql, 1);
 515                 #} else {
 516                 #       $commentedSql = $sql;
 517                 #}
 518
 519                 # If DBO_TRX is set, start a transaction
 520                 if ( ( $this->mFlags & DBO_TRX ) && !$this->trxLevel() &&
 521                         $sql != 'BEGIN' && $sql != 'COMMIT' && $sql != 'ROLLBACK') {
 522                         // avoid establishing transactions for SHOW and SET statements too -
 523                         // that would delay transaction initializations to once connection
 524                         // is really used by application
 525                         $sqlstart = substr($sql,0,10); // very much worth it, benchmark certified(tm)
 526                         if (strpos($sqlstart,"SHOW ")!==0 and strpos($sqlstart,"SET ")!==0)
 527                                 $this->begin();
 528                 }
 529
 530                 if ( $this->debug() ) {
 531                         $sqlx = substr( $commentedSql, 0, 500 );
 532                         $sqlx = strtr( $sqlx, "\t\n", '  ' );
 533                         if ( $isMaster ) {
 534                                 wfDebug( "SQL-master: $sqlx\n" );
 535                         } else {
 536                                 wfDebug( "SQL: $sqlx\n" );
 537                         }
 538                 }
 539
 540                 # Do the query and handle errors
 541                 $ret = $this->doQuery( $commentedSql );
 542
 543                 # Try reconnecting if the connection was lost
 544                 if ( false === $ret && ( $this->lastErrno() == 2013 || $this->lastErrno() == 2006 ) ) {
 545                         # Transaction is gone, like it or not
 546                         $this->mTrxLevel = 0;
 547                         wfDebug( "Connection lost, reconnecting...\n" );
 548                         if ( $this->ping() ) {
 549                                 wfDebug( "Reconnected\n" );
 550                                 $sqlx = substr( $commentedSql, 0, 500 );
 551                                 $sqlx = strtr( $sqlx, "\t\n", '  ' );
 552                                 global $wgRequestTime;
 553                                 $elapsed = round( microtime(true) - $wgRequestTime, 3 );
 554                                 wfLogDBError( "Connection lost and reconnected after {$elapsed}s, query: $sqlx\n" );
 555                                 $ret = $this->doQuery( $commentedSql );
 556                         } else {
 557                                 wfDebug( "Failed\n" );
 558                         }
 559                 }
 560
 561                 if ( false === $ret ) {
 562                         $this->reportQueryError( $this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
 563                 }
 564
 565                 if ( isset( $wgProfiler ) ) {
 566                         wfProfileOut( $queryProf );
 567                         wfProfileOut( $totalProf );
 568                 }
 569                 return $this->resultObject( $ret );
 570         }
 571
 572         /**
 573          * The DBMS-dependent part of query()
 574          * @param  $sql String: SQL query.
 575          * @return Result object to feed to fetchObject, fetchRow, ...; or false on failure
 576          * @access private
 577          */
 578         /*private*/ function doQuery( $sql ) {
 579                 if( $this->bufferResults() ) {
 580                         $ret = mysql_query( $sql, $this->mConn );
 581                 } else {
 582                         $ret = mysql_unbuffered_query( $sql, $this->mConn );
 583                 }
 584                 return $ret;
 585         }
 586
 587         /**
 588          * @param $error
 589          * @param $errno
 590          * @param $sql
 591          * @param string $fname
 592          * @param bool $tempIgnore
 593          */
 594         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 595                 global $wgCommandLineMode;
 596                 # Ignore errors during error handling to avoid infinite recursion
 597                 $ignore = $this->ignoreErrors( true );
 598                 ++$this->mErrorCount;
 599
 600                 if( $ignore || $tempIgnore ) {
 601                         wfDebug("SQL ERROR (ignored): $error\n");
 602                         $this->ignoreErrors( $ignore );
 603                 } else {
 604                         $sql1line = str_replace( "\n", "\\n", $sql );
 605                         wfLogDBError("$fname\t{$this->mServer}\t$errno\t$error\t$sql1line\n");
 606                         wfDebug("SQL ERROR: " . $error . "\n");
 607                         throw new DBQueryError( $this, $error, $errno, $sql, $fname );
 608                 }
 609         }
 610
 611
 612         /**
 613          * Intended to be compatible with the PEAR::DB wrapper functions.
 614          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
 615          *
 616          * ? = scalar value, quoted as necessary
 617          * ! = raw SQL bit (a function for instance)
 618          * & = filename; reads the file and inserts as a blob
 619          *     (we don't use this though...)
 620          */
 621         function prepare( $sql, $func = 'Database::prepare' ) {
 622                 /* MySQL doesn't support prepared statements (yet), so just
 623                    pack up the query for reference. We'll manually replace
 624                    the bits later. */
 625                 return array( 'query' => $sql, 'func' => $func );
 626         }
 627
 628         function freePrepared( $prepared ) {
 629                 /* No-op for MySQL */
 630         }
 631
 632         /**
 633          * Execute a prepared query with the various arguments
 634          * @param string $prepared the prepared sql
 635          * @param mixed $args Either an array here, or put scalars as varargs
 636          */
 637         function execute( $prepared, $args = null ) {
 638                 if( !is_array( $args ) ) {
 639                         # Pull the var args
 640                         $args = func_get_args();
 641                         array_shift( $args );
 642                 }
 643                 $sql = $this->fillPrepared( $prepared['query'], $args );
 644                 return $this->query( $sql, $prepared['func'] );
 645         }
 646
 647         /**
 648          * Prepare & execute an SQL statement, quoting and inserting arguments
 649          * in the appropriate places.
 650          * @param string $query
 651          * @param string $args ...
 652          */
 653         function safeQuery( $query, $args = null ) {
 654                 $prepared = $this->prepare( $query, 'Database::safeQuery' );
 655                 if( !is_array( $args ) ) {
 656                         # Pull the var args
 657                         $args = func_get_args();
 658                         array_shift( $args );
 659                 }
 660                 $retval = $this->execute( $prepared, $args );
 661                 $this->freePrepared( $prepared );
 662                 return $retval;
 663         }
 664
 665         /**
 666          * For faking prepared SQL statements on DBs that don't support
 667          * it directly.
 668          * @param string $preparedSql - a 'preparable' SQL statement
 669          * @param array $args - array of arguments to fill it with
 670          * @return string executable SQL
 671          */
 672         function fillPrepared( $preparedQuery, $args ) {
 673                 reset( $args );
 674                 $this->preparedArgs =& $args;
 675                 return preg_replace_callback( '/(\\\\[?!&]|[?!&])/',
 676                         array( &$this, 'fillPreparedArg' ), $preparedQuery );
 677         }
 678
 679         /**
 680          * preg_callback func for fillPrepared()
 681          * The arguments should be in $this->preparedArgs and must not be touched
 682          * while we're doing this.
 683          *
 684          * @param array $matches
 685          * @return string
 686          * @private
 687          */
 688         function fillPreparedArg( $matches ) {
 689                 switch( $matches[1] ) {
 690                         case '\\?': return '?';
 691                         case '\\!': return '!';
 692                         case '\\&': return '&';
 693                 }
 694                 list( /* $n */ , $arg ) = each( $this->preparedArgs );
 695                 switch( $matches[1] ) {
 696                         case '?': return $this->addQuotes( $arg );
 697                         case '!': return $arg;
 698                         case '&':
 699                                 # return $this->addQuotes( file_get_contents( $arg ) );
 700                                 throw new DBUnexpectedError( $this, '& mode is not implemented. If it\'s really needed, uncomment the line above.' );
 701                         default:
 702                                 throw new DBUnexpectedError( $this, 'Received invalid match. This should never happen!' );
 703                 }
 704         }
 705
 706         /**#@+
 707          * @param mixed $res A SQL result
 708          */
 709         /**
 710          * Free a result object
 711          */
 712         function freeResult( $res ) {
 713                 if ( $res instanceof ResultWrapper ) {
 714                         $res = $res->result;
 715                 }
 716                 if ( !@/**/mysql_free_result( $res ) ) {
 717                         throw new DBUnexpectedError( $this, "Unable to free MySQL result" );
 718                 }
 719         }
 720
 721         /**
 722          * Fetch the next row from the given result object, in object form.
 723          * Fields can be retrieved with $row->fieldname, with fields acting like
 724          * member variables.
 725          *
 726          * @param $res SQL result object as returned from Database::query(), etc.
 727          * @return MySQL row object
 728          * @throws DBUnexpectedError Thrown if the database returns an error
 729          */
 730         function fetchObject( $res ) {
 731                 if ( $res instanceof ResultWrapper ) {
 732                         $res = $res->result;
 733                 }
 734                 @/**/$row = mysql_fetch_object( $res );
 735                 if( $this->lastErrno() ) {
 736                         throw new DBUnexpectedError( $this, 'Error in fetchObject(): ' . htmlspecialchars( $this->lastError() ) );
 737                 }
 738                 return $row;
 739         }
 740
 741         /**
 742          * Fetch the next row from the given result object, in associative array
 743          * form.  Fields are retrieved with $row['fieldname'].
 744          *
 745          * @param $res SQL result object as returned from Database::query(), etc.
 746          * @return MySQL row object
 747          * @throws DBUnexpectedError Thrown if the database returns an error
 748          */
 749         function fetchRow( $res ) {
 750                 if ( $res instanceof ResultWrapper ) {
 751                         $res = $res->result;
 752                 }
 753                 @/**/$row = mysql_fetch_array( $res );
 754                 if ( $this->lastErrno() ) {
 755                         throw new DBUnexpectedError( $this, 'Error in fetchRow(): ' . htmlspecialchars( $this->lastError() ) );
 756                 }
 757                 return $row;
 758         }
 759
 760         /**
 761          * Get the number of rows in a result object
 762          */
 763         function numRows( $res ) {
 764                 if ( $res instanceof ResultWrapper ) {
 765                         $res = $res->result;
 766                 }
 767                 @/**/$n = mysql_num_rows( $res );
 768                 if( $this->lastErrno() ) {
 769                         throw new DBUnexpectedError( $this, 'Error in numRows(): ' . htmlspecialchars( $this->lastError() ) );
 770                 }
 771                 return $n;
 772         }
 773
 774         /**
 775          * Get the number of fields in a result object
 776          * See documentation for mysql_num_fields()
 777          */
 778         function numFields( $res ) {
 779                 if ( $res instanceof ResultWrapper ) {
 780                         $res = $res->result;
 781                 }
 782                 return mysql_num_fields( $res );
 783         }
 784
 785         /**
 786          * Get a field name in a result object
 787          * See documentation for mysql_field_name():
 788          * http://www.php.net/mysql_field_name
 789          */
 790         function fieldName( $res, $n ) {
 791                 if ( $res instanceof ResultWrapper ) {
 792                         $res = $res->result;
 793                 }
 794                 return mysql_field_name( $res, $n );
 795         }
 796
 797         /**
 798          * Get the inserted value of an auto-increment row
 799          *
 800          * The value inserted should be fetched from nextSequenceValue()
 801          *
 802          * Example:
 803          * $id = $dbw->nextSequenceValue('page_page_id_seq');
 804          * $dbw->insert('page',array('page_id' => $id));
 805          * $id = $dbw->insertId();
 806          */
 807         function insertId() { return mysql_insert_id( $this->mConn ); }
 808
 809         /**
 810          * Change the position of the cursor in a result object
 811          * See mysql_data_seek()
 812          */
 813         function dataSeek( $res, $row ) {
 814                 if ( $res instanceof ResultWrapper ) {
 815                         $res = $res->result;
 816                 }
 817                 return mysql_data_seek( $res, $row );
 818         }
 819
 820         /**
 821          * Get the last error number
 822          * See mysql_errno()
 823          */
 824         function lastErrno() {
 825                 if ( $this->mConn ) {
 826                         return mysql_errno( $this->mConn );
 827                 } else {
 828                         return mysql_errno();
 829                 }
 830         }
 831
 832         /**
 833          * Get a description of the last error
 834          * See mysql_error() for more details
 835          */
 836         function lastError() {
 837                 if ( $this->mConn ) {
 838                         # Even if it's non-zero, it can still be invalid
 839                         wfSuppressWarnings();
 840                         $error = mysql_error( $this->mConn );
 841                         if ( !$error ) {
 842                                 $error = mysql_error();
 843                         }
 844                         wfRestoreWarnings();
 845                 } else {
 846                         $error = mysql_error();
 847                 }
 848                 if( $error ) {
 849                         $error .= ' (' . $this->mServer . ')';
 850                 }
 851                 return $error;
 852         }
 853         /**
 854          * Get the number of rows affected by the last write query
 855          * See mysql_affected_rows() for more details
 856          */
 857         function affectedRows() { return mysql_affected_rows( $this->mConn ); }
 858         /**#@-*/ // end of template : @param $result
 859
 860         /**
 861          * Simple UPDATE wrapper
 862          * Usually aborts on failure
 863          * If errors are explicitly ignored, returns success
 864          *
 865          * This function exists for historical reasons, Database::update() has a more standard
 866          * calling convention and feature set
 867          */
 868         function set( $table, $var, $value, $cond, $fname = 'Database::set' )
 869         {
 870                 $table = $this->tableName( $table );
 871                 $sql = "UPDATE $table SET $var = '" .
 872                   $this->strencode( $value ) . "' WHERE ($cond)";
 873                 return (bool)$this->query( $sql, $fname );
 874         }
 875
 876         /**
 877          * Simple SELECT wrapper, returns a single field, input must be encoded
 878          * Usually aborts on failure
 879          * If errors are explicitly ignored, returns FALSE on failure
 880          */
 881         function selectField( $table, $var, $cond='', $fname = 'Database::selectField', $options = array() ) {
 882                 if ( !is_array( $options ) ) {
 883                         $options = array( $options );
 884                 }
 885                 $options['LIMIT'] = 1;
 886
 887                 $res = $this->select( $table, $var, $cond, $fname, $options );
 888                 if ( $res === false || !$this->numRows( $res ) ) {
 889                         return false;
 890                 }
 891                 $row = $this->fetchRow( $res );
 892                 if ( $row !== false ) {
 893                         $this->freeResult( $res );
 894                         return $row[0];
 895                 } else {
 896                         return false;
 897                 }
 898         }
 899
 900         /**
 901          * Returns an optional USE INDEX clause to go after the table, and a
 902          * string to go at the end of the query
 903          *
 904          * @private
 905          *
 906          * @param array $options an associative array of options to be turned into
 907          *              an SQL query, valid keys are listed in the function.
 908          * @return array
 909          */
 910         function makeSelectOptions( $options ) {
 911                 $preLimitTail = $postLimitTail = '';
 912                 $startOpts = '';
 913
 914                 $noKeyOptions = array();
 915                 foreach ( $options as $key => $option ) {
 916                         if ( is_numeric( $key ) ) {
 917                                 $noKeyOptions[$option] = true;
 918                         }
 919                 }
 920
 921                 if ( isset( $options['GROUP BY'] ) ) $preLimitTail .= " GROUP BY {$options['GROUP BY']}";
 922                 if ( isset( $options['HAVING'] ) ) $preLimitTail .= " HAVING {$options['HAVING']}";
 923                 if ( isset( $options['ORDER BY'] ) ) $preLimitTail .= " ORDER BY {$options['ORDER BY']}";
 924
 925                 //if (isset($options['LIMIT'])) {
 926                 //      $tailOpts .= $this->limitResult('', $options['LIMIT'],
 927                 //              isset($options['OFFSET']) ? $options['OFFSET']
 928                 //              : false);
 929                 //}
 930
 931                 if ( isset( $noKeyOptions['FOR UPDATE'] ) ) $postLimitTail .= ' FOR UPDATE';
 932                 if ( isset( $noKeyOptions['LOCK IN SHARE MODE'] ) ) $postLimitTail .= ' LOCK IN SHARE MODE';
 933                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) $startOpts .= 'DISTINCT';
 934
 935                 # Various MySQL extensions
 936                 if ( isset( $noKeyOptions['STRAIGHT_JOIN'] ) ) $startOpts .= ' /*! STRAIGHT_JOIN */';
 937                 if ( isset( $noKeyOptions['HIGH_PRIORITY'] ) ) $startOpts .= ' HIGH_PRIORITY';
 938                 if ( isset( $noKeyOptions['SQL_BIG_RESULT'] ) ) $startOpts .= ' SQL_BIG_RESULT';
 939                 if ( isset( $noKeyOptions['SQL_BUFFER_RESULT'] ) ) $startOpts .= ' SQL_BUFFER_RESULT';
 940                 if ( isset( $noKeyOptions['SQL_SMALL_RESULT'] ) ) $startOpts .= ' SQL_SMALL_RESULT';
 941                 if ( isset( $noKeyOptions['SQL_CALC_FOUND_ROWS'] ) ) $startOpts .= ' SQL_CALC_FOUND_ROWS';
 942                 if ( isset( $noKeyOptions['SQL_CACHE'] ) ) $startOpts .= ' SQL_CACHE';
 943                 if ( isset( $noKeyOptions['SQL_NO_CACHE'] ) ) $startOpts .= ' SQL_NO_CACHE';
 944
 945                 if ( isset( $options['USE INDEX'] ) && ! is_array( $options['USE INDEX'] ) ) {
 946                         $useIndex = $this->useIndexClause( $options['USE INDEX'] );
 947                 } else {
 948                         $useIndex = '';
 949                 }
 950
 951                 return array( $startOpts, $useIndex, $preLimitTail, $postLimitTail );
 952         }
 953
 954         /**
 955          * SELECT wrapper
 956          *
 957          * @param mixed  $table   Array or string, table name(s) (prefix auto-added)
 958          * @param mixed  $vars    Array or string, field name(s) to be retrieved
 959          * @param mixed  $conds   Array or string, condition(s) for WHERE
 960          * @param string $fname   Calling function name (use __METHOD__) for logs/profiling
 961          * @param array  $options Associative array of options (e.g. array('GROUP BY' => 'page_title')),
 962          *                        see Database::makeSelectOptions code for list of supported stuff
 963          * @param array $join_conds Associative array of table join conditions (optional)
 964          *                        (e.g. array( 'page' => array('LEFT JOIN','page_latest=rev_id') )
 965          * @return mixed Database result resource (feed to Database::fetchObject or whatever), or false on failure
 966          */
 967         function select( $table, $vars, $conds='', $fname = 'Database::select', $options = array(), $join_conds = array() )
 968         {
 969                 $sql = $this->selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 970                 return $this->query( $sql, $fname );
 971         }
 972
 973         /**
 974          * SELECT wrapper
 975          *
 976          * @param mixed  $table   Array or string, table name(s) (prefix auto-added)
 977          * @param mixed  $vars    Array or string, field name(s) to be retrieved
 978          * @param mixed  $conds   Array or string, condition(s) for WHERE
 979          * @param string $fname   Calling function name (use __METHOD__) for logs/profiling
 980          * @param array  $options Associative array of options (e.g. array('GROUP BY' => 'page_title')),
 981          *                        see Database::makeSelectOptions code for list of supported stuff
 982          * @param array $join_conds Associative array of table join conditions (optional)
 983          *                        (e.g. array( 'page' => array('LEFT JOIN','page_latest=rev_id') )
 984          * @return string, the SQL text
 985          */
 986         function selectSQLText( $table, $vars, $conds='', $fname = 'Database::select', $options = array(), $join_conds = array() ) {
 987                 if( is_array( $vars ) ) {
 988                         $vars = implode( ',', $vars );
 989                 }
 990                 if( !is_array( $options ) ) {
 991                         $options = array( $options );
 992                 }
 993                 if( is_array( $table ) ) {
 994                         if ( !empty($join_conds) || ( isset( $options['USE INDEX'] ) && is_array( @$options['USE INDEX'] ) ) )
 995                                 $from = ' FROM ' . $this->tableNamesWithUseIndexOrJOIN( $table, @$options['USE INDEX'], $join_conds );
 996                         else
 997                                 $from = ' FROM ' . implode( ',', array_map( array( &$this, 'tableName' ), $table ) );
 998                 } elseif ($table!='') {
 999                         if ($table{0}==' ') {
1000                                 $from = ' FROM ' . $table;
1001                         } else {
1002                                 $from = ' FROM ' . $this->tableName( $table );
1003                         }
1004                 } else {
1005                         $from = '';
1006                 }
1007
1008                 list( $startOpts, $useIndex, $preLimitTail, $postLimitTail ) = $this->makeSelectOptions( $options );
1009
1010                 if( !empty( $conds ) ) {
1011                         if ( is_array( $conds ) ) {
1012                                 $conds = $this->makeList( $conds, LIST_AND );
1013                         }
1014                         $sql = "SELECT $startOpts $vars $from $useIndex WHERE $conds $preLimitTail";
1015                 } else {
1016                         $sql = "SELECT $startOpts $vars $from $useIndex $preLimitTail";
1017                 }
1018
1019                 if (isset($options['LIMIT']))
1020                         $sql = $this->limitResult($sql, $options['LIMIT'],
1021                                 isset($options['OFFSET']) ? $options['OFFSET'] : false);
1022                 $sql = "$sql $postLimitTail";
1023
1024                 if (isset($options['EXPLAIN'])) {
1025                         $sql = 'EXPLAIN ' . $sql;
1026                 }
1027                 return $sql;
1028         }
1029
1030         /**
1031          * Single row SELECT wrapper
1032          * Aborts or returns FALSE on error
1033          *
1034          * $vars: the selected variables
1035          * $conds: a condition map, terms are ANDed together.
1036          *   Items with numeric keys are taken to be literal conditions
1037          * Takes an array of selected variables, and a condition map, which is ANDed
1038          * e.g: selectRow( "page", array( "page_id" ), array( "page_namespace" =>
1039          * NS_MAIN, "page_title" => "Astronomy" ) )   would return an object where
1040          * $obj- >page_id is the ID of the Astronomy article
1041          *
1042          * @todo migrate documentation to phpdocumentor format
1043          */
1044         function selectRow( $table, $vars, $conds, $fname = 'Database::selectRow', $options = array(), $join_conds = array() ) {
1045                 $options['LIMIT'] = 1;
1046                 $res = $this->select( $table, $vars, $conds, $fname, $options, $join_conds );
1047                 if ( $res === false )
1048                         return false;
1049                 if ( !$this->numRows($res) ) {
1050                         $this->freeResult($res);
1051                         return false;
1052                 }
1053                 $obj = $this->fetchObject( $res );
1054                 $this->freeResult( $res );
1055                 return $obj;
1056
1057         }
1058
1059         /**
1060          * Estimate rows in dataset
1061          * Returns estimated count, based on EXPLAIN output
1062          * Takes same arguments as Database::select()
1063          */
1064
1065         function estimateRowCount( $table, $vars='*', $conds='', $fname = 'Database::estimateRowCount', $options = array() ) {
1066                 $options['EXPLAIN']=true;
1067                 $res = $this->select ($table, $vars, $conds, $fname, $options );
1068                 if ( $res === false )
1069                         return false;
1070                 if (!$this->numRows($res)) {
1071                         $this->freeResult($res);
1072                         return 0;
1073                 }
1074
1075                 $rows=1;
1076
1077                 while( $plan = $this->fetchObject( $res ) ) {
1078                         $rows *= ($plan->rows > 0)?$plan->rows:1; // avoid resetting to zero
1079                 }
1080
1081                 $this->freeResult($res);
1082                 return $rows;
1083         }
1084
1085
1086         /**
1087          * Removes most variables from an SQL query and replaces them with X or N for numbers.
1088          * It's only slightly flawed. Don't use for anything important.
1089          *
1090          * @param string $sql A SQL Query
1091          * @static
1092          */
1093         static function generalizeSQL( $sql ) {
1094                 # This does the same as the regexp below would do, but in such a way
1095                 # as to avoid crashing php on some large strings.
1096                 # $sql = preg_replace ( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql);
1097
1098                 $sql = str_replace ( "\\\\", '', $sql);
1099                 $sql = str_replace ( "\\'", '', $sql);
1100                 $sql = str_replace ( "\\\"", '', $sql);
1101                 $sql = preg_replace ("/'.*'/s", "'X'", $sql);
1102                 $sql = preg_replace ('/".*"/s', "'X'", $sql);
1103
1104                 # All newlines, tabs, etc replaced by single space
1105                 $sql = preg_replace ( '/\s+/', ' ', $sql);
1106
1107                 # All numbers => N
1108                 $sql = preg_replace ('/-?[0-9]+/s', 'N', $sql);
1109
1110                 return $sql;
1111         }
1112
1113         /**
1114          * Determines whether a field exists in a table
1115          * Usually aborts on failure
1116          * If errors are explicitly ignored, returns NULL on failure
1117          */
1118         function fieldExists( $table, $field, $fname = 'Database::fieldExists' ) {
1119                 $table = $this->tableName( $table );
1120                 $res = $this->query( 'DESCRIBE '.$table, $fname );
1121                 if ( !$res ) {
1122                         return NULL;
1123                 }
1124
1125                 $found = false;
1126
1127                 while ( $row = $this->fetchObject( $res ) ) {
1128                         if ( $row->Field == $field ) {
1129                                 $found = true;
1130                                 break;
1131                         }
1132                 }
1133                 return $found;
1134         }
1135
1136         /**
1137          * Determines whether an index exists
1138          * Usually aborts on failure
1139          * If errors are explicitly ignored, returns NULL on failure
1140          */
1141         function indexExists( $table, $index, $fname = 'Database::indexExists' ) {
1142                 $info = $this->indexInfo( $table, $index, $fname );
1143                 if ( is_null( $info ) ) {
1144                         return NULL;
1145                 } else {
1146                         return $info !== false;
1147                 }
1148         }
1149
1150
1151         /**
1152          * Get information about an index into an object
1153          * Returns false if the index does not exist
1154          */
1155         function indexInfo( $table, $index, $fname = 'Database::indexInfo' ) {
1156                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
1157                 # SHOW INDEX should work for 3.x and up:
1158                 # http://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
1159                 $table = $this->tableName( $table );
1160                 $sql = 'SHOW INDEX FROM '.$table;
1161                 $res = $this->query( $sql, $fname );
1162                 if ( !$res ) {
1163                         return NULL;
1164                 }
1165
1166                 $result = array();
1167                 while ( $row = $this->fetchObject( $res ) ) {
1168                         if ( $row->Key_name == $index ) {
1169                                 $result[] = $row;
1170                         }
1171                 }
1172                 $this->freeResult($res);
1173
1174                 return empty($result) ? false : $result;
1175         }
1176
1177         /**
1178          * Query whether a given table exists
1179          */
1180         function tableExists( $table ) {
1181                 $table = $this->tableName( $table );
1182                 $old = $this->ignoreErrors( true );
1183                 $res = $this->query( "SELECT 1 FROM $table LIMIT 1" );
1184                 $this->ignoreErrors( $old );
1185                 if( $res ) {
1186                         $this->freeResult( $res );
1187                         return true;
1188                 } else {
1189                         return false;
1190                 }
1191         }
1192
1193         /**
1194          * mysql_fetch_field() wrapper
1195          * Returns false if the field doesn't exist
1196          *
1197          * @param $table
1198          * @param $field
1199          */
1200         function fieldInfo( $table, $field ) {
1201                 $table = $this->tableName( $table );
1202                 $res = $this->query( "SELECT * FROM $table LIMIT 1" );
1203                 $n = mysql_num_fields( $res->result );
1204                 for( $i = 0; $i < $n; $i++ ) {
1205                         $meta = mysql_fetch_field( $res->result, $i );
1206                         if( $field == $meta->name ) {
1207                                 return new MySQLField($meta);
1208                         }
1209                 }
1210                 return false;
1211         }
1212
1213         /**
1214          * mysql_field_type() wrapper
1215          */
1216         function fieldType( $res, $index ) {
1217                 if ( $res instanceof ResultWrapper ) {
1218                         $res = $res->result;
1219                 }
1220                 return mysql_field_type( $res, $index );
1221         }
1222
1223         /**
1224          * Determines if a given index is unique
1225          */
1226         function indexUnique( $table, $index ) {
1227                 $indexInfo = $this->indexInfo( $table, $index );
1228                 if ( !$indexInfo ) {
1229                         return NULL;
1230                 }
1231                 return !$indexInfo[0]->Non_unique;
1232         }
1233
1234         /**
1235          * INSERT wrapper, inserts an array into a table
1236          *
1237          * $a may be a single associative array, or an array of these with numeric keys, for
1238          * multi-row insert.
1239          *
1240          * Usually aborts on failure
1241          * If errors are explicitly ignored, returns success
1242          */
1243         function insert( $table, $a, $fname = 'Database::insert', $options = array() ) {
1244                 # No rows to insert, easy just return now
1245                 if ( !count( $a ) ) {
1246                         return true;
1247                 }
1248
1249                 $table = $this->tableName( $table );
1250                 if ( !is_array( $options ) ) {
1251                         $options = array( $options );
1252                 }
1253                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
1254                         $multi = true;
1255                         $keys = array_keys( $a[0] );
1256                 } else {
1257                         $multi = false;
1258                         $keys = array_keys( $a );
1259                 }
1260
1261                 $sql = 'INSERT ' . implode( ' ', $options ) .
1262                         " INTO $table (" . implode( ',', $keys ) . ') VALUES ';
1263
1264                 if ( $multi ) {
1265                         $first = true;
1266                         foreach ( $a as $row ) {
1267                                 if ( $first ) {
1268                                         $first = false;
1269                                 } else {
1270                                         $sql .= ',';
1271                                 }
1272                                 $sql .= '(' . $this->makeList( $row ) . ')';
1273                         }
1274                 } else {
1275                         $sql .= '(' . $this->makeList( $a ) . ')';
1276                 }
1277                 return (bool)$this->query( $sql, $fname );
1278         }
1279
1280         /**
1281          * Make UPDATE options for the Database::update function
1282          *
1283          * @private
1284          * @param array $options The options passed to Database::update
1285          * @return string
1286          */
1287         function makeUpdateOptions( $options ) {
1288                 if( !is_array( $options ) ) {
1289                         $options = array( $options );
1290                 }
1291                 $opts = array();
1292                 if ( in_array( 'LOW_PRIORITY', $options ) )
1293                         $opts[] = $this->lowPriorityOption();
1294                 if ( in_array( 'IGNORE', $options ) )
1295                         $opts[] = 'IGNORE';
1296                 return implode(' ', $opts);
1297         }
1298
1299         /**
1300          * UPDATE wrapper, takes a condition array and a SET array
1301          *
1302          * @param string $table  The table to UPDATE
1303          * @param array  $values An array of values to SET
1304          * @param array  $conds  An array of conditions (WHERE). Use '*' to update all rows.
1305          * @param string $fname  The Class::Function calling this function
1306          *                       (for the log)
1307          * @param array  $options An array of UPDATE options, can be one or
1308          *                        more of IGNORE, LOW_PRIORITY
1309          * @return bool
1310          */
1311         function update( $table, $values, $conds, $fname = 'Database::update', $options = array() ) {
1312                 $table = $this->tableName( $table );
1313                 $opts = $this->makeUpdateOptions( $options );
1314                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET );
1315                 if ( $conds != '*' ) {
1316                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1317                 }
1318                 return $this->query( $sql, $fname );
1319         }
1320
1321         /**
1322          * Makes an encoded list of strings from an array
1323          * $mode:
1324          *        LIST_COMMA         - comma separated, no field names
1325          *        LIST_AND           - ANDed WHERE clause (without the WHERE)
1326          *        LIST_OR            - ORed WHERE clause (without the WHERE)
1327          *        LIST_SET           - comma separated with field names, like a SET clause
1328          *        LIST_NAMES         - comma separated field names
1329          */
1330         function makeList( $a, $mode = LIST_COMMA ) {
1331                 if ( !is_array( $a ) ) {
1332                         throw new DBUnexpectedError( $this, 'Database::makeList called with incorrect parameters' );
1333                 }
1334
1335                 $first = true;
1336                 $list = '';
1337                 foreach ( $a as $field => $value ) {
1338                         if ( !$first ) {
1339                                 if ( $mode == LIST_AND ) {
1340                                         $list .= ' AND ';
1341                                 } elseif($mode == LIST_OR) {
1342                                         $list .= ' OR ';
1343                                 } else {
1344                                         $list .= ',';
1345                                 }
1346                         } else {
1347                                 $first = false;
1348                         }
1349                         if ( ($mode == LIST_AND || $mode == LIST_OR) && is_numeric( $field ) ) {
1350                                 $list .= "($value)";
1351                         } elseif ( ($mode == LIST_SET) && is_numeric( $field ) ) {
1352                                 $list .= "$value";
1353                         } elseif ( ($mode == LIST_AND || $mode == LIST_OR) && is_array($value) ) {
1354                                 if( count( $value ) == 0 ) {
1355                                         throw new MWException( __METHOD__.': empty input' );
1356                                 } elseif( count( $value ) == 1 ) {
1357                                         // Special-case single values, as IN isn't terribly efficient
1358                                         // Don't necessarily assume the single key is 0; we don't
1359                                         // enforce linear numeric ordering on other arrays here.
1360                                         $value = array_values( $value );
1361                                         $list .= $field." = ".$this->addQuotes( $value[0] );
1362                                 } else {
1363                                         $list .= $field." IN (".$this->makeList($value).") ";
1364                                 }
1365                         } elseif( is_null($value) ) {
1366                                 if ( $mode == LIST_AND || $mode == LIST_OR ) {
1367                                         $list .= "$field IS ";
1368                                 } elseif ( $mode == LIST_SET ) {
1369                                         $list .= "$field = ";
1370                                 }
1371                                 $list .= 'NULL';
1372                         } else {
1373                                 if ( $mode == LIST_AND || $mode == LIST_OR || $mode == LIST_SET ) {
1374                                         $list .= "$field = ";
1375                                 }
1376                                 $list .= $mode == LIST_NAMES ? $value : $this->addQuotes( $value );
1377                         }
1378                 }
1379                 return $list;
1380         }
1381
1382         /**
1383          * Change the current database
1384          */
1385         function selectDB( $db ) {
1386                 $this->mDBname = $db;
1387                 return mysql_select_db( $db, $this->mConn );
1388         }
1389
1390         /**
1391          * Get the current DB name
1392          */
1393         function getDBname() {
1394                 return $this->mDBname;
1395         }
1396
1397         /**
1398          * Get the server hostname or IP address
1399          */
1400         function getServer() {
1401                 return $this->mServer;
1402         }
1403
1404         /**
1405          * Format a table name ready for use in constructing an SQL query
1406          *
1407          * This does two important things: it quotes the table names to clean them up,
1408          * and it adds a table prefix if only given a table name with no quotes.
1409          *
1410          * All functions of this object which require a table name call this function
1411          * themselves. Pass the canonical name to such functions. This is only needed
1412          * when calling query() directly.
1413          *
1414          * @param string $name database table name
1415          * @return string full database name
1416          */
1417         function tableName( $name ) {
1418                 global $wgSharedDB, $wgSharedPrefix, $wgSharedTables;
1419                 # Skip the entire process when we have a string quoted on both ends.
1420                 # Note that we check the end so that we will still quote any use of
1421                 # use of `database`.table. But won't break things if someone wants
1422                 # to query a database table with a dot in the name.
1423                 if ( $name[0] == '`' && substr( $name, -1, 1 ) == '`' ) return $name;
1424
1425                 # Lets test for any bits of text that should never show up in a table
1426                 # name. Basically anything like JOIN or ON which are actually part of
1427                 # SQL queries, but may end up inside of the table value to combine
1428                 # sql. Such as how the API is doing.
1429                 # Note that we use a whitespace test rather than a \b test to avoid
1430                 # any remote case where a word like on may be inside of a table name
1431                 # surrounded by symbols which may be considered word breaks.
1432                 if( preg_match( '/(^|\s)(DISTINCT|JOIN|ON|AS)(\s|$)/i', $name ) !== 0 ) return $name;
1433
1434                 # Split database and table into proper variables.
1435                 # We reverse the explode so that database.table and table both output
1436                 # the correct table.
1437                 $dbDetails = array_reverse( explode( '.', $name, 2 ) );
1438                 if( isset( $dbDetails[1] ) ) @list( $table, $database ) = $dbDetails;
1439                 else                         @list( $table ) = $dbDetails;
1440                 $prefix = $this->mTablePrefix; # Default prefix
1441
1442                 # A database name has been specified in input. Quote the table name
1443                 # because we don't want any prefixes added.
1444                 if( isset($database) ) $table = ( $table[0] == '`' ? $table : "`{$table}`" );
1445
1446                 # Note that we use the long format because php will complain in in_array if
1447                 # the input is not an array, and will complain in is_array if it is not set.
1448                 if( !isset( $database ) # Don't use shared database if pre selected.
1449                  && isset( $wgSharedDB ) # We have a shared database
1450                  && $table[0] != '`' # Paranoia check to prevent shared tables listing '`table`'
1451                  && isset( $wgSharedTables )
1452                  && is_array( $wgSharedTables )
1453                  && in_array( $table, $wgSharedTables ) ) { # A shared table is selected
1454                         $database = $wgSharedDB;
1455                         $prefix   = isset( $wgSharedprefix ) ? $wgSharedprefix : $prefix;
1456                 }
1457
1458                 # Quote the $database and $table and apply the prefix if not quoted.
1459                 if( isset($database) ) $database = ( $database[0] == '`' ? $database : "`{$database}`" );
1460                 $table = ( $table[0] == '`' ? $table : "`{$prefix}{$table}`" );
1461
1462                 # Merge our database and table into our final table name.
1463                 $tableName = ( isset($database) ? "{$database}.{$table}" : "{$table}" );
1464
1465                 # We're finished, return.
1466                 return $tableName;
1467         }
1468
1469         /**
1470          * Fetch a number of table names into an array
1471          * This is handy when you need to construct SQL for joins
1472          *
1473          * Example:
1474          * extract($dbr->tableNames('user','watchlist'));
1475          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1476          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1477          */
1478         public function tableNames() {
1479                 $inArray = func_get_args();
1480                 $retVal = array();
1481                 foreach ( $inArray as $name ) {
1482                         $retVal[$name] = $this->tableName( $name );
1483                 }
1484                 return $retVal;
1485         }
1486
1487         /**
1488          * Fetch a number of table names into an zero-indexed numerical array
1489          * This is handy when you need to construct SQL for joins
1490          *
1491          * Example:
1492          * list( $user, $watchlist ) = $dbr->tableNamesN('user','watchlist');
1493          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1494          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1495          */
1496         public function tableNamesN() {
1497                 $inArray = func_get_args();
1498                 $retVal = array();
1499                 foreach ( $inArray as $name ) {
1500                         $retVal[] = $this->tableName( $name );
1501                 }
1502                 return $retVal;
1503         }
1504
1505         /**
1506          * @private
1507          */
1508         function tableNamesWithUseIndexOrJOIN( $tables, $use_index = array(), $join_conds = array() ) {
1509                 $ret = array();
1510                 $retJOIN = array();
1511                 $use_index_safe = is_array($use_index) ? $use_index : array();
1512                 $join_conds_safe = is_array($join_conds) ? $join_conds : array();
1513                 foreach ( $tables as $table ) {
1514                         // Is there a JOIN and INDEX clause for this table?
1515                         if ( isset($join_conds_safe[$table]) && isset($use_index_safe[$table]) ) {
1516                                 $tableClause = $join_conds_safe[$table][0] . ' ' . $this->tableName( $table );
1517                                 $tableClause .= ' ' . $this->useIndexClause( implode( ',', (array)$use_index_safe[$table] ) );
1518                                 $tableClause .= ' ON (' . $this->makeList((array)$join_conds_safe[$table][1], LIST_AND) . ')';
1519                                 $retJOIN[] = $tableClause;
1520                         // Is there an INDEX clause?
1521                         } else if ( isset($use_index_safe[$table]) ) {
1522                                 $tableClause = $this->tableName( $table );
1523                                 $tableClause .= ' ' . $this->useIndexClause( implode( ',', (array)$use_index_safe[$table] ) );
1524                                 $ret[] = $tableClause;
1525                         // Is there a JOIN clause?
1526                         } else if ( isset($join_conds_safe[$table]) ) {
1527                                 $tableClause = $join_conds_safe[$table][0] . ' ' . $this->tableName( $table );
1528                                 $tableClause .= ' ON (' . $this->makeList((array)$join_conds_safe[$table][1], LIST_AND) . ')';
1529                                 $retJOIN[] = $tableClause;
1530                         } else {
1531                                 $tableClause = $this->tableName( $table );
1532                                 $ret[] = $tableClause;
1533                         }
1534                 }
1535                 // We can't separate explicit JOIN clauses with ',', use ' ' for those
1536                 $straightJoins = !empty($ret) ? implode( ',', $ret ) : "";
1537                 $otherJoins = !empty($retJOIN) ? implode( ' ', $retJOIN ) : "";
1538                 // Compile our final table clause
1539                 return implode(' ',array($straightJoins,$otherJoins) );
1540         }
1541
1542         /**
1543          * Wrapper for addslashes()
1544          * @param string $s String to be slashed.
1545          * @return string slashed string.
1546          */
1547         function strencode( $s ) {
1548                 return mysql_real_escape_string( $s, $this->mConn );
1549         }
1550
1551         /**
1552          * If it's a string, adds quotes and backslashes
1553          * Otherwise returns as-is
1554          */
1555         function addQuotes( $s ) {
1556                 if ( is_null( $s ) ) {
1557                         return 'NULL';
1558                 } else {
1559                         # This will also quote numeric values. This should be harmless,
1560                         # and protects against weird problems that occur when they really
1561                         # _are_ strings such as article titles and string->number->string
1562                         # conversion is not 1:1.
1563                         return "'" . $this->strencode( $s ) . "'";
1564                 }
1565         }
1566
1567         /**
1568          * Escape string for safe LIKE usage
1569          */
1570         function escapeLike( $s ) {
1571                 $s=$this->strencode( $s );
1572                 $s=str_replace(array('%','_'),array('\%','\_'),$s);
1573                 return $s;
1574         }
1575
1576         /**
1577          * Returns an appropriately quoted sequence value for inserting a new row.
1578          * MySQL has autoincrement fields, so this is just NULL. But the PostgreSQL
1579          * subclass will return an integer, and save the value for insertId()
1580          */
1581         function nextSequenceValue( $seqName ) {
1582                 return NULL;
1583         }
1584
1585         /**
1586          * USE INDEX clause
1587          * PostgreSQL doesn't have them and returns ""
1588          */
1589         function useIndexClause( $index ) {
1590                 return "FORCE INDEX ($index)";
1591         }
1592
1593         /**
1594          * REPLACE query wrapper
1595          * PostgreSQL simulates this with a DELETE followed by INSERT
1596          * $row is the row to insert, an associative array
1597          * $uniqueIndexes is an array of indexes. Each element may be either a
1598          * field name or an array of field names
1599          *
1600          * It may be more efficient to leave off unique indexes which are unlikely to collide.
1601          * However if you do this, you run the risk of encountering errors which wouldn't have
1602          * occurred in MySQL
1603          *
1604          * @todo migrate comment to phodocumentor format
1605          */
1606         function replace( $table, $uniqueIndexes, $rows, $fname = 'Database::replace' ) {
1607                 $table = $this->tableName( $table );
1608
1609                 # Single row case
1610                 if ( !is_array( reset( $rows ) ) ) {
1611                         $rows = array( $rows );
1612                 }
1613
1614                 $sql = "REPLACE INTO $table (" . implode( ',', array_keys( $rows[0] ) ) .') VALUES ';
1615                 $first = true;
1616                 foreach ( $rows as $row ) {
1617                         if ( $first ) {
1618                                 $first = false;
1619                         } else {
1620                                 $sql .= ',';
1621                         }
1622                         $sql .= '(' . $this->makeList( $row ) . ')';
1623                 }
1624                 return $this->query( $sql, $fname );
1625         }
1626
1627         /**
1628          * DELETE where the condition is a join
1629          * MySQL does this with a multi-table DELETE syntax, PostgreSQL does it with sub-selects
1630          *
1631          * For safety, an empty $conds will not delete everything. If you want to delete all rows where the
1632          * join condition matches, set $conds='*'
1633          *
1634          * DO NOT put the join condition in $conds
1635          *
1636          * @param string $delTable The table to delete from.
1637          * @param string $joinTable The other table.
1638          * @param string $delVar The variable to join on, in the first table.
1639          * @param string $joinVar The variable to join on, in the second table.
1640          * @param array $conds Condition array of field names mapped to variables, ANDed together in the WHERE clause
1641          */
1642         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = 'Database::deleteJoin' ) {
1643                 if ( !$conds ) {
1644                         throw new DBUnexpectedError( $this, 'Database::deleteJoin() called with empty $conds' );
1645                 }
1646
1647                 $delTable = $this->tableName( $delTable );
1648                 $joinTable = $this->tableName( $joinTable );
1649                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
1650                 if ( $conds != '*' ) {
1651                         $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
1652                 }
1653
1654                 return $this->query( $sql, $fname );
1655         }
1656
1657         /**
1658          * Returns the size of a text field, or -1 for "unlimited"
1659          */
1660         function textFieldSize( $table, $field ) {
1661                 $table = $this->tableName( $table );
1662                 $sql = "SHOW COLUMNS FROM $table LIKE \"$field\";";
1663                 $res = $this->query( $sql, 'Database::textFieldSize' );
1664                 $row = $this->fetchObject( $res );
1665                 $this->freeResult( $res );
1666
1667                 $m = array();
1668                 if ( preg_match( '/\((.*)\)/', $row->Type, $m ) ) {
1669                         $size = $m[1];
1670                 } else {
1671                         $size = -1;
1672                 }
1673                 return $size;
1674         }
1675
1676         /**
1677          * @return string Returns the text of the low priority option if it is supported, or a blank string otherwise
1678          */
1679         function lowPriorityOption() {
1680                 return 'LOW_PRIORITY';
1681         }
1682
1683         /**
1684          * DELETE query wrapper
1685          *
1686          * Use $conds == "*" to delete all rows
1687          */
1688         function delete( $table, $conds, $fname = 'Database::delete' ) {
1689                 if ( !$conds ) {
1690                         throw new DBUnexpectedError( $this, 'Database::delete() called with no conditions' );
1691                 }
1692                 $table = $this->tableName( $table );
1693                 $sql = "DELETE FROM $table";
1694                 if ( $conds != '*' ) {
1695                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1696                 }
1697                 return $this->query( $sql, $fname );
1698         }
1699
1700         /**
1701          * INSERT SELECT wrapper
1702          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
1703          * Source items may be literals rather than field names, but strings should be quoted with Database::addQuotes()
1704          * $conds may be "*" to copy the whole table
1705          * srcTable may be an array of tables.
1706          */
1707         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'Database::insertSelect',
1708                 $insertOptions = array(), $selectOptions = array() )
1709         {
1710                 $destTable = $this->tableName( $destTable );
1711                 if ( is_array( $insertOptions ) ) {
1712                         $insertOptions = implode( ' ', $insertOptions );
1713                 }
1714                 if( !is_array( $selectOptions ) ) {
1715                         $selectOptions = array( $selectOptions );
1716                 }
1717                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
1718                 if( is_array( $srcTable ) ) {
1719                         $srcTable =  implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
1720                 } else {
1721                         $srcTable = $this->tableName( $srcTable );
1722                 }
1723                 $sql = "INSERT $insertOptions INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
1724                         " SELECT $startOpts " . implode( ',', $varMap ) .
1725                         " FROM $srcTable $useIndex ";
1726                 if ( $conds != '*' ) {
1727                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1728                 }
1729                 $sql .= " $tailOpts";
1730                 return $this->query( $sql, $fname );
1731         }
1732
1733         /**
1734          * Construct a LIMIT query with optional offset
1735          * This is used for query pages
1736          * $sql string SQL query we will append the limit too
1737          * $limit integer the SQL limit
1738          * $offset integer the SQL offset (default false)
1739          */
1740         function limitResult($sql, $limit, $offset=false) {
1741                 if( !is_numeric($limit) ) {
1742                         throw new DBUnexpectedError( $this, "Invalid non-numeric limit passed to limitResult()\n" );
1743                 }
1744                 return "$sql LIMIT "
1745                                 . ( (is_numeric($offset) && $offset != 0) ? "{$offset}," : "" )
1746                                 . "{$limit} ";
1747         }
1748         function limitResultForUpdate($sql, $num) {
1749                 return $this->limitResult($sql, $num, 0);
1750         }
1751
1752         /**
1753          * Returns an SQL expression for a simple conditional.
1754          * Uses IF on MySQL.
1755          *
1756          * @param string $cond SQL expression which will result in a boolean value
1757          * @param string $trueVal SQL expression to return if true
1758          * @param string $falseVal SQL expression to return if false
1759          * @return string SQL fragment
1760          */
1761         function conditional( $cond, $trueVal, $falseVal ) {
1762                 return " IF($cond, $trueVal, $falseVal) ";
1763         }
1764
1765         /**
1766          * Returns a comand for str_replace function in SQL query.
1767          * Uses REPLACE() in MySQL
1768          *
1769          * @param string $orig String or column to modify
1770          * @param string $old String or column to seek
1771          * @param string $new String or column to replace with
1772          */
1773         function strreplace( $orig, $old, $new ) {
1774                 return "REPLACE({$orig}, {$old}, {$new})";
1775         }
1776
1777         /**
1778          * Determines if the last failure was due to a deadlock
1779          */
1780         function wasDeadlock() {
1781                 return $this->lastErrno() == 1213;
1782         }
1783
1784         /**
1785          * Perform a deadlock-prone transaction.
1786          *
1787          * This function invokes a callback function to perform a set of write
1788          * queries. If a deadlock occurs during the processing, the transaction
1789          * will be rolled back and the callback function will be called again.
1790          *
1791          * Usage:
1792          *   $dbw->deadlockLoop( callback, ... );
1793          *
1794          * Extra arguments are passed through to the specified callback function.
1795          *
1796          * Returns whatever the callback function returned on its successful,
1797          * iteration, or false on error, for example if the retry limit was
1798          * reached.
1799          */
1800         function deadlockLoop() {
1801                 $myFname = 'Database::deadlockLoop';
1802
1803                 $this->begin();
1804                 $args = func_get_args();
1805                 $function = array_shift( $args );
1806                 $oldIgnore = $this->ignoreErrors( true );
1807                 $tries = DEADLOCK_TRIES;
1808                 if ( is_array( $function ) ) {
1809                         $fname = $function[0];
1810                 } else {
1811                         $fname = $function;
1812                 }
1813                 do {
1814                         $retVal = call_user_func_array( $function, $args );
1815                         $error = $this->lastError();
1816                         $errno = $this->lastErrno();
1817                         $sql = $this->lastQuery();
1818
1819                         if ( $errno ) {
1820                                 if ( $this->wasDeadlock() ) {
1821                                         # Retry
1822                                         usleep( mt_rand( DEADLOCK_DELAY_MIN, DEADLOCK_DELAY_MAX ) );
1823                                 } else {
1824                                         $this->reportQueryError( $error, $errno, $sql, $fname );
1825                                 }
1826                         }
1827                 } while( $this->wasDeadlock() && --$tries > 0 );
1828                 $this->ignoreErrors( $oldIgnore );
1829                 if ( $tries <= 0 ) {
1830                         $this->query( 'ROLLBACK', $myFname );
1831                         $this->reportQueryError( $error, $errno, $sql, $fname );
1832                         return false;
1833                 } else {
1834                         $this->query( 'COMMIT', $myFname );
1835                         return $retVal;
1836                 }
1837         }
1838
1839         /**
1840          * Do a SELECT MASTER_POS_WAIT()
1841          *
1842          * @param string $file the binlog file
1843          * @param string $pos the binlog position
1844          * @param integer $timeout the maximum number of seconds to wait for synchronisation
1845          */
1846         function masterPosWait( MySQLMasterPos $pos, $timeout ) {
1847                 $fname = 'Database::masterPosWait';
1848                 wfProfileIn( $fname );
1849
1850                 # Commit any open transactions
1851                 if ( $this->mTrxLevel ) {
1852                         $this->immediateCommit();
1853                 }
1854
1855                 if ( !is_null( $this->mFakeSlaveLag ) ) {
1856                         $wait = intval( ( $pos->pos - microtime(true) + $this->mFakeSlaveLag ) * 1e6 );
1857                         if ( $wait > $timeout * 1e6 ) {
1858                                 wfDebug( "Fake slave timed out waiting for $pos ($wait us)\n" );
1859                                 wfProfileOut( $fname );
1860                                 return -1;
1861                         } elseif ( $wait > 0 ) {
1862                                 wfDebug( "Fake slave waiting $wait us\n" );
1863                                 usleep( $wait );
1864                                 wfProfileOut( $fname );
1865                                 return 1;
1866                         } else {
1867                                 wfDebug( "Fake slave up to date ($wait us)\n" );
1868                                 wfProfileOut( $fname );
1869                                 return 0;
1870                         }
1871                 }
1872
1873                 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
1874                 $encFile = $this->addQuotes( $pos->file );
1875                 $encPos = intval( $pos->pos );
1876                 $sql = "SELECT MASTER_POS_WAIT($encFile, $encPos, $timeout)";
1877                 $res = $this->doQuery( $sql );
1878                 if ( $res && $row = $this->fetchRow( $res ) ) {
1879                         $this->freeResult( $res );
1880                         wfProfileOut( $fname );
1881                         return $row[0];
1882                 } else {
1883                         wfProfileOut( $fname );
1884                         return false;
1885                 }
1886         }
1887
1888         /**
1889          * Get the position of the master from SHOW SLAVE STATUS
1890          */
1891         function getSlavePos() {
1892                 if ( !is_null( $this->mFakeSlaveLag ) ) {
1893                         $pos = new MySQLMasterPos( 'fake', microtime(true) - $this->mFakeSlaveLag );
1894                         wfDebug( __METHOD__.": fake slave pos = $pos\n" );
1895                         return $pos;
1896                 }
1897                 $res = $this->query( 'SHOW SLAVE STATUS', 'Database::getSlavePos' );
1898                 $row = $this->fetchObject( $res );
1899                 if ( $row ) {
1900                         return new MySQLMasterPos( $row->Master_Log_File, $row->Read_Master_Log_Pos );
1901                 } else {
1902                         return false;
1903                 }
1904         }
1905
1906         /**
1907          * Get the position of the master from SHOW MASTER STATUS
1908          */
1909         function getMasterPos() {
1910                 if ( $this->mFakeMaster ) {
1911                         return new MySQLMasterPos( 'fake', microtime( true ) );
1912                 }
1913                 $res = $this->query( 'SHOW MASTER STATUS', 'Database::getMasterPos' );
1914                 $row = $this->fetchObject( $res );
1915                 if ( $row ) {
1916                         return new MySQLMasterPos( $row->File, $row->Position );
1917                 } else {
1918                         return false;
1919                 }
1920         }
1921
1922         /**
1923          * Begin a transaction, committing any previously open transaction
1924          */
1925         function begin( $fname = 'Database::begin' ) {
1926                 $this->query( 'BEGIN', $fname );
1927                 $this->mTrxLevel = 1;
1928         }
1929
1930         /**
1931          * End a transaction
1932          */
1933         function commit( $fname = 'Database::commit' ) {
1934                 $this->query( 'COMMIT', $fname );
1935                 $this->mTrxLevel = 0;
1936         }
1937
1938         /**
1939          * Rollback a transaction.
1940          * No-op on non-transactional databases.
1941          */
1942         function rollback( $fname = 'Database::rollback' ) {
1943                 $this->query( 'ROLLBACK', $fname, true );
1944                 $this->mTrxLevel = 0;
1945         }
1946
1947         /**
1948          * Begin a transaction, committing any previously open transaction
1949          * @deprecated use begin()
1950          */
1951         function immediateBegin( $fname = 'Database::immediateBegin' ) {
1952                 $this->begin();
1953         }
1954
1955         /**
1956          * Commit transaction, if one is open
1957          * @deprecated use commit()
1958          */
1959         function immediateCommit( $fname = 'Database::immediateCommit' ) {
1960                 $this->commit();
1961         }
1962
1963         /**
1964          * Return MW-style timestamp used for MySQL schema
1965          */
1966         function timestamp( $ts=0 ) {
1967                 return wfTimestamp(TS_MW,$ts);
1968         }
1969
1970         /**
1971          * Local database timestamp format or null
1972          */
1973         function timestampOrNull( $ts = null ) {
1974                 if( is_null( $ts ) ) {
1975                         return null;
1976                 } else {
1977                         return $this->timestamp( $ts );
1978                 }
1979         }
1980
1981         /**
1982          * @todo document
1983          */
1984         function resultObject( $result ) {
1985                 if( empty( $result ) ) {
1986                         return false;
1987                 } elseif ( $result instanceof ResultWrapper ) {
1988                         return $result;
1989                 } elseif ( $result === true ) {
1990                         // Successful write query
1991                         return $result;
1992                 } else {
1993                         return new ResultWrapper( $this, $result );
1994                 }
1995         }
1996
1997         /**
1998          * Return aggregated value alias
1999          */
2000         function aggregateValue ($valuedata,$valuename='value') {
2001                 return $valuename;
2002         }
2003
2004         /**
2005          * @return string wikitext of a link to the server software's web site
2006          */
2007         function getSoftwareLink() {
2008                 return "[http://www.mysql.com/ MySQL]";
2009         }
2010
2011         /**
2012          * @return string Version information from the database
2013          */
2014         function getServerVersion() {
2015                 return mysql_get_server_info( $this->mConn );
2016         }
2017
2018         /**
2019          * Ping the server and try to reconnect if it there is no connection
2020          */
2021         function ping() {
2022                 if( !function_exists( 'mysql_ping' ) ) {
2023                         wfDebug( "Tried to call mysql_ping but this is ancient PHP version. Faking it!\n" );
2024                         return true;
2025                 }
2026                 $ping = mysql_ping( $this->mConn );
2027                 if ( $ping ) {
2028                         return true;
2029                 }
2030
2031                 // Need to reconnect manually in MySQL client 5.0.13+
2032                 if ( version_compare( mysql_get_client_info(), '5.0.13', '>=' ) ) {
2033                         mysql_close( $this->mConn );
2034                         $this->mOpened = false;
2035                         $this->mConn = false;
2036                         $this->open( $this->mServer, $this->mUser, $this->mPassword, $this->mDBname );
2037                         return true;
2038                 }
2039                 return false;
2040         }
2041
2042         /**
2043          * Get slave lag.
2044          * At the moment, this will only work if the DB user has the PROCESS privilege
2045          */
2046         function getLag() {
2047                 if ( !is_null( $this->mFakeSlaveLag ) ) {
2048                         wfDebug( "getLag: fake slave lagged {$this->mFakeSlaveLag} seconds\n" );
2049                         return $this->mFakeSlaveLag;
2050                 }
2051                 $res = $this->query( 'SHOW PROCESSLIST' );
2052                 # Find slave SQL thread
2053                 while ( $row = $this->fetchObject( $res ) ) {
2054                         /* This should work for most situations - when default db
2055                          * for thread is not specified, it had no events executed,
2056                          * and therefore it doesn't know yet how lagged it is.
2057                          *
2058                          * Relay log I/O thread does not select databases.
2059                          */
2060                         if ( $row->User == 'system user' &&
2061                                 $row->State != 'Waiting for master to send event' &&
2062                                 $row->State != 'Connecting to master' &&
2063                                 $row->State != 'Queueing master event to the relay log' &&
2064                                 $row->State != 'Waiting for master update' &&
2065                                 $row->State != 'Requesting binlog dump'
2066                                 ) {
2067                                 # This is it, return the time (except -ve)
2068                                 if ( $row->Time > 0x7fffffff ) {
2069                                         return false;
2070                                 } else {
2071                                         return $row->Time;
2072                                 }
2073                         }
2074                 }
2075                 return false;
2076         }
2077
2078         /**
2079          * Get status information from SHOW STATUS in an associative array
2080          */
2081         function getStatus($which="%") {
2082                 $res = $this->query( "SHOW STATUS LIKE '{$which}'" );
2083                 $status = array();
2084                 while ( $row = $this->fetchObject( $res ) ) {
2085                         $status[$row->Variable_name] = $row->Value;
2086                 }
2087                 return $status;
2088         }
2089
2090         /**
2091          * Return the maximum number of items allowed in a list, or 0 for unlimited.
2092          */
2093         function maxListLen() {
2094                 return 0;
2095         }
2096
2097         function encodeBlob($b) {
2098                 return $b;
2099         }
2100
2101         function decodeBlob($b) {
2102                 return $b;
2103         }
2104
2105         /**
2106          * Override database's default connection timeout.
2107          * May be useful for very long batch queries such as
2108          * full-wiki dumps, where a single query reads out
2109          * over hours or days.
2110          * @param int $timeout in seconds
2111          */
2112         public function setTimeout( $timeout ) {
2113                 $this->query( "SET net_read_timeout=$timeout" );
2114                 $this->query( "SET net_write_timeout=$timeout" );
2115         }
2116
2117         /**
2118          * Read and execute SQL commands from a file.
2119          * Returns true on success, error string or exception on failure (depending on object's error ignore settings)
2120          * @param string $filename File name to open
2121          * @param callback $lineCallback Optional function called before reading each line
2122          * @param callback $resultCallback Optional function called for each MySQL result
2123          */
2124         function sourceFile( $filename, $lineCallback = false, $resultCallback = false ) {
2125                 $fp = fopen( $filename, 'r' );
2126                 if ( false === $fp ) {
2127                         throw new MWException( "Could not open \"{$filename}\".\n" );
2128                 }
2129                 $error = $this->sourceStream( $fp, $lineCallback, $resultCallback );
2130                 fclose( $fp );
2131                 return $error;
2132         }
2133
2134         /**
2135          * Read and execute commands from an open file handle
2136          * Returns true on success, error string or exception on failure (depending on object's error ignore settings)
2137          * @param string $fp File handle
2138          * @param callback $lineCallback Optional function called before reading each line
2139          * @param callback $resultCallback Optional function called for each MySQL result
2140          */
2141         function sourceStream( $fp, $lineCallback = false, $resultCallback = false ) {
2142                 $cmd = "";
2143                 $done = false;
2144                 $dollarquote = false;
2145
2146                 while ( ! feof( $fp ) ) {
2147                         if ( $lineCallback ) {
2148                                 call_user_func( $lineCallback );
2149                         }
2150                         $line = trim( fgets( $fp, 1024 ) );
2151                         $sl = strlen( $line ) - 1;
2152
2153                         if ( $sl < 0 ) { continue; }
2154                         if ( '-' == $line{0} && '-' == $line{1} ) { continue; }
2155
2156                         ## Allow dollar quoting for function declarations
2157                         if (substr($line,0,4) == '$mw$') {
2158                                 if ($dollarquote) {
2159                                         $dollarquote = false;
2160                                         $done = true;
2161                                 }
2162                                 else {
2163                                         $dollarquote = true;
2164                                 }
2165                         }
2166                         else if (!$dollarquote) {
2167                                 if ( ';' == $line{$sl} && ($sl < 2 || ';' != $line{$sl - 1})) {
2168                                         $done = true;
2169                                         $line = substr( $line, 0, $sl );
2170                                 }
2171                         }
2172
2173                         if ( '' != $cmd ) { $cmd .= ' '; }
2174                         $cmd .= "$line\n";
2175
2176                         if ( $done ) {
2177                                 $cmd = str_replace(';;', ";", $cmd);
2178                                 $cmd = $this->replaceVars( $cmd );
2179                                 $res = $this->query( $cmd, __METHOD__ );
2180                                 if ( $resultCallback ) {
2181                                         call_user_func( $resultCallback, $res );
2182                                 }
2183
2184                                 if ( false === $res ) {
2185                                         $err = $this->lastError();
2186                                         return "Query \"{$cmd}\" failed with error code \"$err\".\n";
2187                                 }
2188
2189                                 $cmd = '';
2190                                 $done = false;
2191                         }
2192                 }
2193                 return true;
2194         }
2195
2196
2197         /**
2198          * Replace variables in sourced SQL
2199          */
2200         protected function replaceVars( $ins ) {
2201                 $varnames = array(
2202                         'wgDBserver', 'wgDBname', 'wgDBintlname', 'wgDBuser',
2203                         'wgDBpassword', 'wgDBsqluser', 'wgDBsqlpassword',
2204                         'wgDBadminuser', 'wgDBadminpassword', 'wgDBTableOptions',
2205                 );
2206
2207                 // Ordinary variables
2208                 foreach ( $varnames as $var ) {
2209                         if( isset( $GLOBALS[$var] ) ) {
2210                                 $val = addslashes( $GLOBALS[$var] ); // FIXME: safety check?
2211                                 $ins = str_replace( '{$' . $var . '}', $val, $ins );
2212                                 $ins = str_replace( '/*$' . $var . '*/`', '`' . $val, $ins );
2213                                 $ins = str_replace( '/*$' . $var . '*/', $val, $ins );
2214                         }
2215                 }
2216
2217                 // Table prefixes
2218                 $ins = preg_replace_callback( '/\/\*(?:\$wgDBprefix|_)\*\/([a-zA-Z_0-9]*)/',
2219                         array( &$this, 'tableNameCallback' ), $ins );
2220                 return $ins;
2221         }
2222
2223         /**
2224          * Table name callback
2225          * @private
2226          */
2227         protected function tableNameCallback( $matches ) {
2228                 return $this->tableName( $matches[1] );
2229         }
2230
2231         /*
2232          * Build a concatenation list to feed into a SQL query
2233         */
2234         function buildConcat( $stringList ) {
2235                 return 'CONCAT(' . implode( ',', $stringList ) . ')';
2236         }
2237
2238         /**
2239          * Acquire a lock
2240          *
2241          * Abstracted from Filestore::lock() so child classes can implement for
2242          * their own needs.
2243          *
2244          * @param string $lockName Name of lock to aquire
2245          * @param string $method Name of method calling us
2246          * @return bool
2247          */
2248         public function lock( $lockName, $method ) {
2249                 $lockName = $this->addQuotes( $lockName );
2250                 $result = $this->query( "SELECT GET_LOCK($lockName, 5) AS lockstatus", $method );
2251                 $row = $this->fetchObject( $result );
2252                 $this->freeResult( $result );
2253
2254                 if( $row->lockstatus == 1 ) {
2255                         return true;
2256                 } else {
2257                         wfDebug( __METHOD__." failed to acquire lock\n" );
2258                         return false;
2259                 }
2260         }
2261         /**
2262          * Release a lock.
2263          *
2264          * @todo fixme - Figure out a way to return a bool
2265          * based on successful lock release.
2266          *
2267          * @param string $lockName Name of lock to release
2268          * @param string $method Name of method calling us
2269          */
2270         public function unlock( $lockName, $method ) {
2271                 $lockName = $this->addQuotes( $lockName );
2272                 $result = $this->query( "SELECT RELEASE_LOCK($lockName)", $method );
2273                 $this->freeResult( $result );
2274         }
2275 }
2276
2277 /**
2278  * Database abstraction object for mySQL
2279  * Inherit all methods and properties of Database::Database()
2280  *
2281  * @ingroup Database
2282  * @see Database
2283  */
2284 class DatabaseMysql extends Database {
2285         # Inherit all
2286 }
2287
2288 /******************************************************************************
2289  * Utility classes
2290  *****************************************************************************/
2291
2292 /**
2293  * Utility class.
2294  * @ingroup Database
2295  */
2296 class DBObject {
2297         public $mData;
2298
2299         function DBObject($data) {
2300                 $this->mData = $data;
2301         }
2302
2303         function isLOB() {
2304                 return false;
2305         }
2306
2307         function data() {
2308                 return $this->mData;
2309         }
2310 }
2311
2312 /**
2313  * Utility class
2314  * @ingroup Database
2315  *
2316  * This allows us to distinguish a blob from a normal string and an array of strings
2317  */
2318 class Blob {
2319         private $mData;
2320         function __construct($data) {
2321                 $this->mData = $data;
2322         }
2323         function fetch() {
2324                 return $this->mData;
2325         }
2326 }
2327
2328 /**
2329  * Utility class.
2330  * @ingroup Database
2331  */
2332 class MySQLField {
2333         private $name, $tablename, $default, $max_length, $nullable,
2334                 $is_pk, $is_unique, $is_multiple, $is_key, $type;
2335         function __construct ($info) {
2336                 $this->name = $info->name;
2337                 $this->tablename = $info->table;
2338                 $this->default = $info->def;
2339                 $this->max_length = $info->max_length;
2340                 $this->nullable = !$info->not_null;
2341                 $this->is_pk = $info->primary_key;
2342                 $this->is_unique = $info->unique_key;
2343                 $this->is_multiple = $info->multiple_key;
2344                 $this->is_key = ($this->is_pk || $this->is_unique || $this->is_multiple);
2345                 $this->type = $info->type;
2346         }
2347
2348         function name() {
2349                 return $this->name;
2350         }
2351
2352         function tableName() {
2353                 return $this->tableName;
2354         }
2355
2356         function defaultValue() {
2357                 return $this->default;
2358         }
2359
2360         function maxLength() {
2361                 return $this->max_length;
2362         }
2363
2364         function nullable() {
2365                 return $this->nullable;
2366         }
2367
2368         function isKey() {
2369                 return $this->is_key;
2370         }
2371
2372         function isMultipleKey() {
2373                 return $this->is_multiple;
2374         }
2375
2376         function type() {
2377                 return $this->type;
2378         }
2379 }
2380
2381 /******************************************************************************
2382  * Error classes
2383  *****************************************************************************/
2384
2385 /**
2386  * Database error base class
2387  * @ingroup Database
2388  */
2389 class DBError extends MWException {
2390         public $db;
2391
2392         /**
2393          * Construct a database error
2394          * @param Database $db The database object which threw the error
2395          * @param string $error A simple error message to be used for debugging
2396          */
2397         function __construct( Database &$db, $error ) {
2398                 $this->db =& $db;
2399                 parent::__construct( $error );
2400         }
2401 }
2402
2403 /**
2404  * @ingroup Database
2405  */
2406 class DBConnectionError extends DBError {
2407         public $error;
2408
2409         function __construct( Database &$db, $error = 'unknown error' ) {
2410                 $msg = 'DB connection error';
2411                 if ( trim( $error ) != '' ) {
2412                         $msg .= ": $error";
2413                 }
2414                 $this->error = $error;
2415                 parent::__construct( $db, $msg );
2416         }
2417
2418         function useOutputPage() {
2419                 // Not likely to work
2420                 return false;
2421         }
2422
2423         function useMessageCache() {
2424                 // Not likely to work
2425                 return false;
2426         }
2427
2428         function getText() {
2429                 return $this->getMessage() . "\n";
2430         }
2431
2432         function getLogMessage() {
2433                 # Don't send to the exception log
2434                 return false;
2435         }
2436
2437         function getPageTitle() {
2438                 global $wgSitename;
2439                 return "$wgSitename has a problem";
2440         }
2441
2442         function getHTML() {
2443                 global $wgTitle, $wgUseFileCache, $title, $wgInputEncoding;
2444                 global $wgSitename, $wgServer, $wgMessageCache;
2445
2446                 # I give up, Brion is right. Getting the message cache to work when there is no DB is tricky.
2447                 # Hard coding strings instead.
2448
2449                 $noconnect = "<p><strong>Sorry! This site is experiencing technical difficulties.</strong></p><p>Try waiting a few minutes and reloading.</p><p><small>(Can't contact the database server: $1)</small></p>";
2450                 $mainpage = 'Main Page';
2451                 $searchdisabled = <<<EOT
2452 <p style="margin: 1.5em 2em 1em">$wgSitename search is disabled for performance reasons. You can search via Google in the meantime.
2453 <span style="font-size: 89%; display: block; margin-left: .2em">Note that their indexes of $wgSitename content may be out of date.</span></p>',
2454 EOT;
2455
2456                 $googlesearch = "
2457 <!-- SiteSearch Google -->
2458 <FORM method=GET action=\"http://www.google.com/search\">
2459 <TABLE bgcolor=\"#FFFFFF\"><tr><td>
2460 <A HREF=\"http://www.google.com/\">
2461 <IMG SRC=\"http://www.google.com/logos/Logo_40wht.gif\"
2462 border=\"0\" ALT=\"Google\"></A>
2463 </td>
2464 <td>
2465 <INPUT TYPE=text name=q size=31 maxlength=255 value=\"$1\">
2466 <INPUT type=submit name=btnG VALUE=\"Google Search\">
2467 <font size=-1>
2468 <input type=hidden name=domains value=\"$wgServer\"><br /><input type=radio name=sitesearch value=\"\"> WWW <input type=radio name=sitesearch value=\"$wgServer\" checked> $wgServer <br />
2469 <input type='hidden' name='ie' value='$2'>
2470 <input type='hidden' name='oe' value='$2'>
2471 </font>
2472 </td></tr></TABLE>
2473 </FORM>
2474 <!-- SiteSearch Google -->";
2475                 $cachederror = "The following is a cached copy of the requested page, and may not be up to date. ";
2476
2477                 # No database access
2478                 if ( is_object( $wgMessageCache ) ) {
2479                         $wgMessageCache->disable();
2480                 }
2481
2482                 if ( trim( $this->error ) == '' ) {
2483                         $this->error = $this->db->getProperty('mServer');
2484                 }
2485
2486                 $text = str_replace( '$1', $this->error, $noconnect );
2487                 $text .= wfGetSiteNotice();
2488
2489                 if($wgUseFileCache) {
2490                         if($wgTitle) {
2491                                 $t =& $wgTitle;
2492                         } else {
2493                                 if($title) {
2494                                         $t = Title::newFromURL( $title );
2495                                 } elseif (@/**/$_REQUEST['search']) {
2496                                         $search = $_REQUEST['search'];
2497                                         return $searchdisabled .
2498                                           str_replace( array( '$1', '$2' ), array( htmlspecialchars( $search ),
2499                                           $wgInputEncoding ), $googlesearch );
2500                                 } else {
2501                                         $t = Title::newFromText( $mainpage );
2502                                 }
2503                         }
2504
2505                         $cache = new HTMLFileCache( $t );
2506                         if( $cache->isFileCached() ) {
2507                                 // @todo, FIXME: $msg is not defined on the next line.
2508                                 $msg = '<p style="color: red"><b>'.$msg."<br />\n" .
2509                                         $cachederror . "</b></p>\n";
2510
2511                                 $tag = '<div id="article">';
2512                                 $text = str_replace(
2513                                         $tag,
2514                                         $tag . $msg,
2515                                         $cache->fetchPageText() );
2516                         }
2517                 }
2518
2519                 return $text;
2520         }
2521 }
2522
2523 /**
2524  * @ingroup Database
2525  */
2526 class DBQueryError extends DBError {
2527         public $error, $errno, $sql, $fname;
2528
2529         function __construct( Database &$db, $error, $errno, $sql, $fname ) {
2530                 $message = "A database error has occurred\n" .
2531                   "Query: $sql\n" .
2532                   "Function: $fname\n" .
2533                   "Error: $errno $error\n";
2534
2535                 parent::__construct( $db, $message );
2536                 $this->error = $error;
2537                 $this->errno = $errno;
2538                 $this->sql = $sql;
2539                 $this->fname = $fname;
2540         }
2541
2542         function getText() {
2543                 if ( $this->useMessageCache() ) {
2544                         return wfMsg( 'dberrortextcl', htmlspecialchars( $this->getSQL() ),
2545                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) ) . "\n";
2546                 } else {
2547                         return $this->getMessage();
2548                 }
2549         }
2550
2551         function getSQL() {
2552                 global $wgShowSQLErrors;
2553                 if( !$wgShowSQLErrors ) {
2554                         return $this->msg( 'sqlhidden', 'SQL hidden' );
2555                 } else {
2556                         return $this->sql;
2557                 }
2558         }
2559
2560         function getLogMessage() {
2561                 # Don't send to the exception log
2562                 return false;
2563         }
2564
2565         function getPageTitle() {
2566                 return $this->msg( 'databaseerror', 'Database error' );
2567         }
2568
2569         function getHTML() {
2570                 if ( $this->useMessageCache() ) {
2571                         return wfMsgNoDB( 'dberrortext', htmlspecialchars( $this->getSQL() ),
2572                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) );
2573                 } else {
2574                         return nl2br( htmlspecialchars( $this->getMessage() ) );
2575                 }
2576         }
2577 }
2578
2579 /**
2580  * @ingroup Database
2581  */
2582 class DBUnexpectedError extends DBError {}
2583
2584
2585 /**
2586  * Result wrapper for grabbing data queried by someone else
2587  * @ingroup Database
2588  */
2589 class ResultWrapper implements Iterator {
2590         var $db, $result, $pos = 0, $currentRow = null;
2591
2592         /**
2593          * Create a new result object from a result resource and a Database object
2594          */
2595         function ResultWrapper( $database, $result ) {
2596                 $this->db = $database;
2597                 if ( $result instanceof ResultWrapper ) {
2598                         $this->result = $result->result;
2599                 } else {
2600                         $this->result = $result;
2601                 }
2602         }
2603
2604         /**
2605          * Get the number of rows in a result object
2606          */
2607         function numRows() {
2608                 return $this->db->numRows( $this->result );
2609         }
2610
2611         /**
2612          * Fetch the next row from the given result object, in object form.
2613          * Fields can be retrieved with $row->fieldname, with fields acting like
2614          * member variables.
2615          *
2616          * @param $res SQL result object as returned from Database::query(), etc.
2617          * @return MySQL row object
2618          * @throws DBUnexpectedError Thrown if the database returns an error
2619          */
2620         function fetchObject() {
2621                 return $this->db->fetchObject( $this->result );
2622         }
2623
2624         /**
2625          * Fetch the next row from the given result object, in associative array
2626          * form.  Fields are retrieved with $row['fieldname'].
2627          *
2628          * @param $res SQL result object as returned from Database::query(), etc.
2629          * @return MySQL row object
2630          * @throws DBUnexpectedError Thrown if the database returns an error
2631          */
2632         function fetchRow() {
2633                 return $this->db->fetchRow( $this->result );
2634         }
2635
2636         /**
2637          * Free a result object
2638          */
2639         function free() {
2640                 $this->db->freeResult( $this->result );
2641                 unset( $this->result );
2642                 unset( $this->db );
2643         }
2644
2645         /**
2646          * Change the position of the cursor in a result object
2647          * See mysql_data_seek()
2648          */
2649         function seek( $row ) {
2650                 $this->db->dataSeek( $this->result, $row );
2651         }
2652
2653         /*********************
2654          * Iterator functions
2655          * Note that using these in combination with the non-iterator functions
2656          * above may cause rows to be skipped or repeated.
2657          */
2658
2659         function rewind() {
2660                 if ($this->numRows()) {
2661                         $this->db->dataSeek($this->result, 0);
2662                 }
2663                 $this->pos = 0;
2664                 $this->currentRow = null;
2665         }
2666
2667         function current() {
2668                 if ( is_null( $this->currentRow ) ) {
2669                         $this->next();
2670                 }
2671                 return $this->currentRow;
2672         }
2673
2674         function key() {
2675                 return $this->pos;
2676         }
2677
2678         function next() {
2679                 $this->pos++;
2680                 $this->currentRow = $this->fetchObject();
2681                 return $this->currentRow;
2682         }
2683
2684         function valid() {
2685                 return $this->current() !== false;
2686         }
2687 }
2688
2689 class MySQLMasterPos {
2690         var $file, $pos;
2691
2692         function __construct( $file, $pos ) {
2693                 $this->file = $file;
2694                 $this->pos = $pos;
2695         }
2696
2697         function __toString() {
2698                 return "{$this->file}/{$this->pos}";
2699         }
2700 }