includes/db/Database.php

   1 <?php
   2 /**
   3  * @defgroup Database Database
   4  *
   5  * @file
   6  * @ingroup Database
   7  * This file deals with MySQL interface functions
   8  * and query specifics/optimisations
   9  */
  10
  11 /** Number of times to re-try an operation in case of deadlock */
  12 define( 'DEADLOCK_TRIES', 4 );
  13 /** Minimum time to wait before retry, in microseconds */
  14 define( 'DEADLOCK_DELAY_MIN', 500000 );
  15 /** Maximum time to wait before retry */
  16 define( 'DEADLOCK_DELAY_MAX', 1500000 );
  17
  18 /**
  19  * Database abstraction object
  20  * @ingroup Database
  21  */
  22 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 $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                 wfDeprecated( __METHOD__ );
  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          * Return the last query that went through Database::query()
 210          * @return string
 211          */
 212         function lastQuery() { return $this->mLastQuery; }
 213
 214         /**
 215          * Is a connection to the database open?
 216          * @return bool
 217          */
 218         function isOpen() { return $this->mOpened; }
 219
 220         function setFlag( $flag ) {
 221                 $this->mFlags |= $flag;
 222         }
 223
 224         function clearFlag( $flag ) {
 225                 $this->mFlags &= ~$flag;
 226         }
 227
 228         function getFlag( $flag ) {
 229                 return !!($this->mFlags & $flag);
 230         }
 231
 232         /**
 233          * General read-only accessor
 234          */
 235         function getProperty( $name ) {
 236                 return $this->$name;
 237         }
 238
 239         function getWikiID() {
 240                 if( $this->mTablePrefix ) {
 241                         return "{$this->mDBname}-{$this->mTablePrefix}";
 242                 } else {
 243                         return $this->mDBname;
 244                 }
 245         }
 246
 247 #------------------------------------------------------------------------------
 248 # Other functions
 249 #------------------------------------------------------------------------------
 250
 251         /**@{{
 252          * Constructor.
 253          * @param string $server database server host
 254          * @param string $user database user name
 255          * @param string $password database user password
 256          * @param string $dbname database name
 257          * @param failFunction
 258          * @param $flags
 259          * @param $tablePrefix String: database table prefixes. By default use the prefix gave in LocalSettings.php
 260          * @param int $max, max connection attempts
 261          ** After the first retry (second attempt), each retry waits 1 second
 262          */
 263         function __construct( $server = false, $user = false, $password = false, $dbName = false,
 264                 $failFunction = false, $flags = 0, $tablePrefix = 'get from global', $max = false ) {
 265
 266                 global $wgOut, $wgDBprefix, $wgCommandLineMode;
 267                 # Can't get a reference if it hasn't been set yet
 268                 if ( !isset( $wgOut ) ) {
 269                         $wgOut = NULL;
 270                 }
 271
 272                 $this->mFailFunction = $failFunction;
 273                 $this->mFlags = $flags;
 274
 275                 if ( $this->mFlags & DBO_DEFAULT ) {
 276                         if ( $wgCommandLineMode ) {
 277                                 $this->mFlags &= ~DBO_TRX;
 278                         } else {
 279                                 $this->mFlags |= DBO_TRX;
 280                         }
 281                 }
 282
 283                 /*
 284                 // Faster read-only access
 285                 if ( wfReadOnly() ) {
 286                         $this->mFlags |= DBO_PERSISTENT;
 287                         $this->mFlags &= ~DBO_TRX;
 288                 }*/
 289
 290                 /** Get the default table prefix*/
 291                 if ( $tablePrefix == 'get from global' ) {
 292                         $this->mTablePrefix = $wgDBprefix;
 293                 } else {
 294                         $this->mTablePrefix = $tablePrefix;
 295                 }
 296
 297                 if ( $server ) {
 298                         $this->open( $server, $user, $password, $dbName, $max );
 299                 }
 300         }
 301
 302         /**
 303          * @static
 304          * @param failFunction
 305          * @param $flags
 306          */
 307         static function newFromParams( $server, $user, $password, $dbName, $failFunction = false, $flags = 0 )
 308         {
 309                 return new Database( $server, $user, $password, $dbName, $failFunction, $flags );
 310         }
 311
 312         /**
 313          * Usually aborts on failure
 314          * If the failFunction is set to a non-zero integer, returns success
 315          */
 316         function open( $server, $user, $password, $dbName, $max = false ) {
 317                 global $wguname, $wgAllDBsAreLocalhost;
 318                 wfProfileIn( __METHOD__ );
 319
 320                 # Test for missing mysql.so
 321                 # First try to load it
 322                 if (!@extension_loaded('mysql')) {
 323                         @dl('mysql.so');
 324                 }
 325
 326                 # Fail now
 327                 # Otherwise we get a suppressed fatal error, which is very hard to track down
 328                 if ( !function_exists( 'mysql_connect' ) ) {
 329                         throw new DBConnectionError( $this, "MySQL functions missing, have you compiled PHP with the --with-mysql option?\n" );
 330                 }
 331
 332                 # Debugging hack -- fake cluster
 333                 if ( $wgAllDBsAreLocalhost ) {
 334                         $realServer = 'localhost';
 335                 } else {
 336                         $realServer = $server;
 337                 }
 338                 $this->close();
 339                 $this->mServer = $server;
 340                 $this->mUser = $user;
 341                 $this->mPassword = $password;
 342                 $this->mDBname = $dbName;
 343
 344                 $success = false;
 345
 346                 wfProfileIn("dbconnect-$server");
 347
 348                 if( !$max ) { $max = 3; }
 349                 # Try to connect up to three times (by default)
 350                 # The kernel's default SYN retransmission period is far too slow for us,
 351                 # so we use a short timeout plus a manual retry.
 352                 $this->mConn = false;
 353                 $this->installErrorHandler();
 354                 for ( $i = 0; $i < $max && !$this->mConn; $i++ ) {
 355                         if ( $i > 1 ) {
 356                                 usleep( 1000 );
 357                         }
 358                         if ( $this->mFlags & DBO_PERSISTENT ) {
 359                                 $this->mConn = mysql_pconnect( $realServer, $user, $password );
 360                         } else {
 361                                 # Create a new connection...
 362                                 $this->mConn = mysql_connect( $realServer, $user, $password, true );
 363                         }
 364                         if ($this->mConn === false) {
 365                                 #$iplus = $i + 1;
 366                                 #wfLogDBError("Connect loop error $iplus of $max ($server): " . mysql_errno() . " - " . mysql_error()."\n");
 367                         }
 368                 }
 369                 $phpError = $this->restoreErrorHandler();
 370
 371                 wfProfileOut("dbconnect-$server");
 372
 373                 if ( $dbName != '' ) {
 374                         if ( $this->mConn !== false ) {
 375                                 $success = @/**/mysql_select_db( $dbName, $this->mConn );
 376                                 if ( !$success ) {
 377                                         $error = "Error selecting database $dbName on server {$this->mServer} " .
 378                                                 "from client host {$wguname['nodename']}\n";
 379                                         wfLogDBError(" Error selecting database $dbName on server {$this->mServer} \n");
 380                                         wfDebug( $error );
 381                                 }
 382                         } else {
 383                                 wfDebug( "DB connection error\n" );
 384                                 wfDebug( "Server: $server, User: $user, Password: " .
 385                                         substr( $password, 0, 3 ) . "..., error: " . mysql_error() . "\n" );
 386                                 $success = false;
 387                         }
 388                 } else {
 389                         # Delay USE query
 390                         $success = (bool)$this->mConn;
 391                 }
 392
 393                 if ( $success ) {
 394                         $version = $this->getServerVersion();
 395                         if ( version_compare( $version, '4.1' ) >= 0 ) {
 396                                 // Tell the server we're communicating with it in UTF-8.
 397                                 // This may engage various charset conversions.
 398                                 global $wgDBmysql5;
 399                                 if( $wgDBmysql5 ) {
 400                                         $this->query( 'SET NAMES utf8', __METHOD__ );
 401                                 }
 402                                 // Turn off strict mode
 403                                 $this->query( "SET sql_mode = ''", __METHOD__ );
 404                         }
 405
 406                         // Turn off strict mode if it is on
 407                 } else {
 408                         $this->reportConnectionError( $phpError );
 409                 }
 410
 411                 $this->mOpened = $success;
 412                 wfProfileOut( __METHOD__ );
 413                 return $success;
 414         }
 415         /**@}}*/
 416
 417         protected function installErrorHandler() {
 418                 $this->mPHPError = false;
 419                 set_error_handler( array( $this, 'connectionErrorHandler' ) );
 420         }
 421
 422         protected function restoreErrorHandler() {
 423                 restore_error_handler();
 424                 return $this->mPHPError;
 425         }
 426
 427         protected function connectionErrorHandler( $errno,  $errstr ) {
 428                 $this->mPHPError = $errstr;
 429         }
 430
 431         /**
 432          * Closes a database connection.
 433          * if it is open : commits any open transactions
 434          *
 435          * @return bool operation success. true if already closed.
 436          */
 437         function close()
 438         {
 439                 $this->mOpened = false;
 440                 if ( $this->mConn ) {
 441                         if ( $this->trxLevel() ) {
 442                                 $this->immediateCommit();
 443                         }
 444                         return mysql_close( $this->mConn );
 445                 } else {
 446                         return true;
 447                 }
 448         }
 449
 450         /**
 451          * @param string $error fallback error message, used if none is given by MySQL
 452          */
 453         function reportConnectionError( $error = 'Unknown error' ) {
 454                 $myError = $this->lastError();
 455                 if ( $myError ) {
 456                         $error = $myError;
 457                 }
 458
 459                 if ( $this->mFailFunction ) {
 460                         # Legacy error handling method
 461                         if ( !is_int( $this->mFailFunction ) ) {
 462                                 $ff = $this->mFailFunction;
 463                                 $ff( $this, $error );
 464                         }
 465                 } else {
 466                         # New method
 467                         wfLogDBError( "Connection error: $error\n" );
 468                         throw new DBConnectionError( $this, $error );
 469                 }
 470         }
 471
 472         /**
 473          * Usually aborts on failure.  If errors are explicitly ignored, returns success.
 474          *
 475          * @param  $sql        String: SQL query
 476          * @param  $fname      String: Name of the calling function, for profiling/SHOW PROCESSLIST
 477          *     comment (you can use __METHOD__ or add some extra info)
 478          * @param  $tempIgnore Bool:   Whether to avoid throwing an exception on errors...
 479          *     maybe best to catch the exception instead?
 480          * @return true for a successful write query, ResultWrapper object for a successful read query,
 481          *     or false on failure if $tempIgnore set
 482          * @throws DBQueryError Thrown when the database returns an error of any kind
 483          */
 484         public function query( $sql, $fname = '', $tempIgnore = false ) {
 485                 global $wgProfiler;
 486
 487                 $isMaster = !is_null( $this->getLBInfo( 'master' ) );
 488                 if ( isset( $wgProfiler ) ) {
 489                         # generalizeSQL will probably cut down the query to reasonable
 490                         # logging size most of the time. The substr is really just a sanity check.
 491
 492                         # Who's been wasting my precious column space? -- TS
 493                         #$profName = 'query: ' . $fname . ' ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 494
 495                         if ( $isMaster ) {
 496                                 $queryProf = 'query-m: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 497                                 $totalProf = 'Database::query-master';
 498                         } else {
 499                                 $queryProf = 'query: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 500                                 $totalProf = 'Database::query';
 501                         }
 502                         wfProfileIn( $totalProf );
 503                         wfProfileIn( $queryProf );
 504                 }
 505
 506                 $this->mLastQuery = $sql;
 507
 508                 # Add a comment for easy SHOW PROCESSLIST interpretation
 509                 #if ( $fname ) {
 510                         global $wgUser;
 511                         if ( is_object( $wgUser ) && !($wgUser instanceof StubObject) ) {
 512                                 $userName = $wgUser->getName();
 513                                 if ( mb_strlen( $userName ) > 15 ) {
 514                                         $userName = mb_substr( $userName, 0, 15 ) . '...';
 515                                 }
 516                                 $userName = str_replace( '/', '', $userName );
 517                         } else {
 518                                 $userName = '';
 519                         }
 520                         $commentedSql = preg_replace('/\s/', " /* $fname $userName */ ", $sql, 1);
 521                 #} else {
 522                 #       $commentedSql = $sql;
 523                 #}
 524
 525                 # If DBO_TRX is set, start a transaction
 526                 if ( ( $this->mFlags & DBO_TRX ) && !$this->trxLevel() &&
 527                         $sql != 'BEGIN' && $sql != 'COMMIT' && $sql != 'ROLLBACK') {
 528                         // avoid establishing transactions for SHOW and SET statements too -
 529                         // that would delay transaction initializations to once connection
 530                         // is really used by application
 531                         $sqlstart = substr($sql,0,10); // very much worth it, benchmark certified(tm)
 532                         if (strpos($sqlstart,"SHOW ")!==0 and strpos($sqlstart,"SET ")!==0)
 533                                 $this->begin();
 534                 }
 535
 536                 if ( $this->debug() ) {
 537                         $sqlx = substr( $commentedSql, 0, 500 );
 538                         $sqlx = strtr( $sqlx, "\t\n", '  ' );
 539                         if ( $isMaster ) {
 540                                 wfDebug( "SQL-master: $sqlx\n" );
 541                         } else {
 542                                 wfDebug( "SQL: $sqlx\n" );
 543                         }
 544                 }
 545
 546                 # Do the query and handle errors
 547                 $ret = $this->doQuery( $commentedSql );
 548
 549                 # Try reconnecting if the connection was lost
 550                 if ( false === $ret && ( $this->lastErrno() == 2013 || $this->lastErrno() == 2006 ) ) {
 551                         # Transaction is gone, like it or not
 552                         $this->mTrxLevel = 0;
 553                         wfDebug( "Connection lost, reconnecting...\n" );
 554                         if ( $this->ping() ) {
 555                                 wfDebug( "Reconnected\n" );
 556                                 $sqlx = substr( $commentedSql, 0, 500 );
 557                                 $sqlx = strtr( $sqlx, "\t\n", '  ' );
 558                                 global $wgRequestTime;
 559                                 $elapsed = round( microtime(true) - $wgRequestTime, 3 );
 560                                 wfLogDBError( "Connection lost and reconnected after {$elapsed}s, query: $sqlx\n" );
 561                                 $ret = $this->doQuery( $commentedSql );
 562                         } else {
 563                                 wfDebug( "Failed\n" );
 564                         }
 565                 }
 566
 567                 if ( false === $ret ) {
 568                         $this->reportQueryError( $this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
 569                 }
 570
 571                 if ( isset( $wgProfiler ) ) {
 572                         wfProfileOut( $queryProf );
 573                         wfProfileOut( $totalProf );
 574                 }
 575                 return $this->resultObject( $ret );
 576         }
 577
 578         /**
 579          * The DBMS-dependent part of query()
 580          * @param  $sql String: SQL query.
 581          * @return Result object to feed to fetchObject, fetchRow, ...; or false on failure
 582          * @access private
 583          */
 584         /*private*/ function doQuery( $sql ) {
 585                 if( $this->bufferResults() ) {
 586                         $ret = mysql_query( $sql, $this->mConn );
 587                 } else {
 588                         $ret = mysql_unbuffered_query( $sql, $this->mConn );
 589                 }
 590                 return $ret;
 591         }
 592
 593         /**
 594          * @param $error
 595          * @param $errno
 596          * @param $sql
 597          * @param string $fname
 598          * @param bool $tempIgnore
 599          */
 600         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 601                 global $wgCommandLineMode;
 602                 # Ignore errors during error handling to avoid infinite recursion
 603                 $ignore = $this->ignoreErrors( true );
 604                 ++$this->mErrorCount;
 605
 606                 if( $ignore || $tempIgnore ) {
 607                         wfDebug("SQL ERROR (ignored): $error\n");
 608                         $this->ignoreErrors( $ignore );
 609                 } else {
 610                         $sql1line = str_replace( "\n", "\\n", $sql );
 611                         wfLogDBError("$fname\t{$this->mServer}\t$errno\t$error\t$sql1line\n");
 612                         wfDebug("SQL ERROR: " . $error . "\n");
 613                         throw new DBQueryError( $this, $error, $errno, $sql, $fname );
 614                 }
 615         }
 616
 617
 618         /**
 619          * Intended to be compatible with the PEAR::DB wrapper functions.
 620          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
 621          *
 622          * ? = scalar value, quoted as necessary
 623          * ! = raw SQL bit (a function for instance)
 624          * & = filename; reads the file and inserts as a blob
 625          *     (we don't use this though...)
 626          */
 627         function prepare( $sql, $func = 'Database::prepare' ) {
 628                 /* MySQL doesn't support prepared statements (yet), so just
 629                    pack up the query for reference. We'll manually replace
 630                    the bits later. */
 631                 return array( 'query' => $sql, 'func' => $func );
 632         }
 633
 634         function freePrepared( $prepared ) {
 635                 /* No-op for MySQL */
 636         }
 637
 638         /**
 639          * Execute a prepared query with the various arguments
 640          * @param string $prepared the prepared sql
 641          * @param mixed $args Either an array here, or put scalars as varargs
 642          */
 643         function execute( $prepared, $args = null ) {
 644                 if( !is_array( $args ) ) {
 645                         # Pull the var args
 646                         $args = func_get_args();
 647                         array_shift( $args );
 648                 }
 649                 $sql = $this->fillPrepared( $prepared['query'], $args );
 650                 return $this->query( $sql, $prepared['func'] );
 651         }
 652
 653         /**
 654          * Prepare & execute an SQL statement, quoting and inserting arguments
 655          * in the appropriate places.
 656          * @param string $query
 657          * @param string $args ...
 658          */
 659         function safeQuery( $query, $args = null ) {
 660                 $prepared = $this->prepare( $query, 'Database::safeQuery' );
 661                 if( !is_array( $args ) ) {
 662                         # Pull the var args
 663                         $args = func_get_args();
 664                         array_shift( $args );
 665                 }
 666                 $retval = $this->execute( $prepared, $args );
 667                 $this->freePrepared( $prepared );
 668                 return $retval;
 669         }
 670
 671         /**
 672          * For faking prepared SQL statements on DBs that don't support
 673          * it directly.
 674          * @param string $preparedSql - a 'preparable' SQL statement
 675          * @param array $args - array of arguments to fill it with
 676          * @return string executable SQL
 677          */
 678         function fillPrepared( $preparedQuery, $args ) {
 679                 reset( $args );
 680                 $this->preparedArgs =& $args;
 681                 return preg_replace_callback( '/(\\\\[?!&]|[?!&])/',
 682                         array( &$this, 'fillPreparedArg' ), $preparedQuery );
 683         }
 684
 685         /**
 686          * preg_callback func for fillPrepared()
 687          * The arguments should be in $this->preparedArgs and must not be touched
 688          * while we're doing this.
 689          *
 690          * @param array $matches
 691          * @return string
 692          * @private
 693          */
 694         function fillPreparedArg( $matches ) {
 695                 switch( $matches[1] ) {
 696                         case '\\?': return '?';
 697                         case '\\!': return '!';
 698                         case '\\&': return '&';
 699                 }
 700                 list( /* $n */ , $arg ) = each( $this->preparedArgs );
 701                 switch( $matches[1] ) {
 702                         case '?': return $this->addQuotes( $arg );
 703                         case '!': return $arg;
 704                         case '&':
 705                                 # return $this->addQuotes( file_get_contents( $arg ) );
 706                                 throw new DBUnexpectedError( $this, '& mode is not implemented. If it\'s really needed, uncomment the line above.' );
 707                         default:
 708                                 throw new DBUnexpectedError( $this, 'Received invalid match. This should never happen!' );
 709                 }
 710         }
 711
 712         /**#@+
 713          * @param mixed $res A SQL result
 714          */
 715         /**
 716          * Free a result object
 717          */
 718         function freeResult( $res ) {
 719                 if ( $res instanceof ResultWrapper ) {
 720                         $res = $res->result;
 721                 }
 722                 if ( !@/**/mysql_free_result( $res ) ) {
 723                         throw new DBUnexpectedError( $this, "Unable to free MySQL result" );
 724                 }
 725         }
 726
 727         /**
 728          * Fetch the next row from the given result object, in object form.
 729          * Fields can be retrieved with $row->fieldname, with fields acting like
 730          * member variables.
 731          *
 732          * @param $res SQL result object as returned from Database::query(), etc.
 733          * @return MySQL row object
 734          * @throws DBUnexpectedError Thrown if the database returns an error
 735          */
 736         function fetchObject( $res ) {
 737                 if ( $res instanceof ResultWrapper ) {
 738                         $res = $res->result;
 739                 }
 740                 @/**/$row = mysql_fetch_object( $res );
 741                 if( $this->lastErrno() ) {
 742                         throw new DBUnexpectedError( $this, 'Error in fetchObject(): ' . htmlspecialchars( $this->lastError() ) );
 743                 }
 744                 return $row;
 745         }
 746
 747         /**
 748          * Fetch the next row from the given result object, in associative array
 749          * form.  Fields are retrieved with $row['fieldname'].
 750          *
 751          * @param $res SQL result object as returned from Database::query(), etc.
 752          * @return MySQL row object
 753          * @throws DBUnexpectedError Thrown if the database returns an error
 754          */
 755         function fetchRow( $res ) {
 756                 if ( $res instanceof ResultWrapper ) {
 757                         $res = $res->result;
 758                 }
 759                 @/**/$row = mysql_fetch_array( $res );
 760                 if ( $this->lastErrno() ) {
 761                         throw new DBUnexpectedError( $this, 'Error in fetchRow(): ' . htmlspecialchars( $this->lastError() ) );
 762                 }
 763                 return $row;
 764         }
 765
 766         /**
 767          * Get the number of rows in a result object
 768          */
 769         function numRows( $res ) {
 770                 if ( $res instanceof ResultWrapper ) {
 771                         $res = $res->result;
 772                 }
 773                 @/**/$n = mysql_num_rows( $res );
 774                 if( $this->lastErrno() ) {
 775                         throw new DBUnexpectedError( $this, 'Error in numRows(): ' . htmlspecialchars( $this->lastError() ) );
 776                 }
 777                 return $n;
 778         }
 779
 780         /**
 781          * Get the number of fields in a result object
 782          * See documentation for mysql_num_fields()
 783          */
 784         function numFields( $res ) {
 785                 if ( $res instanceof ResultWrapper ) {
 786                         $res = $res->result;
 787                 }
 788                 return mysql_num_fields( $res );
 789         }
 790
 791         /**
 792          * Get a field name in a result object
 793          * See documentation for mysql_field_name():
 794          * http://www.php.net/mysql_field_name
 795          */
 796         function fieldName( $res, $n ) {
 797                 if ( $res instanceof ResultWrapper ) {
 798                         $res = $res->result;
 799                 }
 800                 return mysql_field_name( $res, $n );
 801         }
 802
 803         /**
 804          * Get the inserted value of an auto-increment row
 805          *
 806          * The value inserted should be fetched from nextSequenceValue()
 807          *
 808          * Example:
 809          * $id = $dbw->nextSequenceValue('page_page_id_seq');
 810          * $dbw->insert('page',array('page_id' => $id));
 811          * $id = $dbw->insertId();
 812          */
 813         function insertId() { return mysql_insert_id( $this->mConn ); }
 814
 815         /**
 816          * Change the position of the cursor in a result object
 817          * See mysql_data_seek()
 818          */
 819         function dataSeek( $res, $row ) {
 820                 if ( $res instanceof ResultWrapper ) {
 821                         $res = $res->result;
 822                 }
 823                 return mysql_data_seek( $res, $row );
 824         }
 825
 826         /**
 827          * Get the last error number
 828          * See mysql_errno()
 829          */
 830         function lastErrno() {
 831                 if ( $this->mConn ) {
 832                         return mysql_errno( $this->mConn );
 833                 } else {
 834                         return mysql_errno();
 835                 }
 836         }
 837
 838         /**
 839          * Get a description of the last error
 840          * See mysql_error() for more details
 841          */
 842         function lastError() {
 843                 if ( $this->mConn ) {
 844                         # Even if it's non-zero, it can still be invalid
 845                         wfSuppressWarnings();
 846                         $error = mysql_error( $this->mConn );
 847                         if ( !$error ) {
 848                                 $error = mysql_error();
 849                         }
 850                         wfRestoreWarnings();
 851                 } else {
 852                         $error = mysql_error();
 853                 }
 854                 if( $error ) {
 855                         $error .= ' (' . $this->mServer . ')';
 856                 }
 857                 return $error;
 858         }
 859         /**
 860          * Get the number of rows affected by the last write query
 861          * See mysql_affected_rows() for more details
 862          */
 863         function affectedRows() { return mysql_affected_rows( $this->mConn ); }
 864         /**#@-*/ // end of template : @param $result
 865
 866         /**
 867          * Simple UPDATE wrapper
 868          * Usually aborts on failure
 869          * If errors are explicitly ignored, returns success
 870          *
 871          * This function exists for historical reasons, Database::update() has a more standard
 872          * calling convention and feature set
 873          */
 874         function set( $table, $var, $value, $cond, $fname = 'Database::set' )
 875         {
 876                 $table = $this->tableName( $table );
 877                 $sql = "UPDATE $table SET $var = '" .
 878                   $this->strencode( $value ) . "' WHERE ($cond)";
 879                 return (bool)$this->query( $sql, $fname );
 880         }
 881
 882         /**
 883          * Simple SELECT wrapper, returns a single field, input must be encoded
 884          * Usually aborts on failure
 885          * If errors are explicitly ignored, returns FALSE on failure
 886          */
 887         function selectField( $table, $var, $cond='', $fname = 'Database::selectField', $options = array() ) {
 888                 if ( !is_array( $options ) ) {
 889                         $options = array( $options );
 890                 }
 891                 $options['LIMIT'] = 1;
 892
 893                 $res = $this->select( $table, $var, $cond, $fname, $options );
 894                 if ( $res === false || !$this->numRows( $res ) ) {
 895                         return false;
 896                 }
 897                 $row = $this->fetchRow( $res );
 898                 if ( $row !== false ) {
 899                         $this->freeResult( $res );
 900                         return $row[0];
 901                 } else {
 902                         return false;
 903                 }
 904         }
 905
 906         /**
 907          * Returns an optional USE INDEX clause to go after the table, and a
 908          * string to go at the end of the query
 909          *
 910          * @private
 911          *
 912          * @param array $options an associative array of options to be turned into
 913          *              an SQL query, valid keys are listed in the function.
 914          * @return array
 915          */
 916         function makeSelectOptions( $options ) {
 917                 $preLimitTail = $postLimitTail = '';
 918                 $startOpts = '';
 919
 920                 $noKeyOptions = array();
 921                 foreach ( $options as $key => $option ) {
 922                         if ( is_numeric( $key ) ) {
 923                                 $noKeyOptions[$option] = true;
 924                         }
 925                 }
 926
 927                 if ( isset( $options['GROUP BY'] ) ) $preLimitTail .= " GROUP BY {$options['GROUP BY']}";
 928                 if ( isset( $options['HAVING'] ) ) $preLimitTail .= " HAVING {$options['HAVING']}";
 929                 if ( isset( $options['ORDER BY'] ) ) $preLimitTail .= " ORDER BY {$options['ORDER BY']}";
 930
 931                 //if (isset($options['LIMIT'])) {
 932                 //      $tailOpts .= $this->limitResult('', $options['LIMIT'],
 933                 //              isset($options['OFFSET']) ? $options['OFFSET']
 934                 //              : false);
 935                 //}
 936
 937                 if ( isset( $noKeyOptions['FOR UPDATE'] ) ) $postLimitTail .= ' FOR UPDATE';
 938                 if ( isset( $noKeyOptions['LOCK IN SHARE MODE'] ) ) $postLimitTail .= ' LOCK IN SHARE MODE';
 939                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) $startOpts .= 'DISTINCT';
 940
 941                 # Various MySQL extensions
 942                 if ( isset( $noKeyOptions['STRAIGHT_JOIN'] ) ) $startOpts .= ' /*! STRAIGHT_JOIN */';
 943                 if ( isset( $noKeyOptions['HIGH_PRIORITY'] ) ) $startOpts .= ' HIGH_PRIORITY';
 944                 if ( isset( $noKeyOptions['SQL_BIG_RESULT'] ) ) $startOpts .= ' SQL_BIG_RESULT';
 945                 if ( isset( $noKeyOptions['SQL_BUFFER_RESULT'] ) ) $startOpts .= ' SQL_BUFFER_RESULT';
 946                 if ( isset( $noKeyOptions['SQL_SMALL_RESULT'] ) ) $startOpts .= ' SQL_SMALL_RESULT';
 947                 if ( isset( $noKeyOptions['SQL_CALC_FOUND_ROWS'] ) ) $startOpts .= ' SQL_CALC_FOUND_ROWS';
 948                 if ( isset( $noKeyOptions['SQL_CACHE'] ) ) $startOpts .= ' SQL_CACHE';
 949                 if ( isset( $noKeyOptions['SQL_NO_CACHE'] ) ) $startOpts .= ' SQL_NO_CACHE';
 950
 951                 if ( isset( $options['USE INDEX'] ) && ! is_array( $options['USE INDEX'] ) ) {
 952                         $useIndex = $this->useIndexClause( $options['USE INDEX'] );
 953                 } else {
 954                         $useIndex = '';
 955                 }
 956
 957                 return array( $startOpts, $useIndex, $preLimitTail, $postLimitTail );
 958         }
 959
 960         /**
 961          * SELECT wrapper
 962          *
 963          * @param mixed  $table   Array or string, table name(s) (prefix auto-added)
 964          * @param mixed  $vars    Array or string, field name(s) to be retrieved
 965          * @param mixed  $conds   Array or string, condition(s) for WHERE
 966          * @param string $fname   Calling function name (use __METHOD__) for logs/profiling
 967          * @param array  $options Associative array of options (e.g. array('GROUP BY' => 'page_title')),
 968          *                        see Database::makeSelectOptions code for list of supported stuff
 969          * @param array $join_conds Associative array of table join conditions (optional)
 970          *                        (e.g. array( 'page' => array('LEFT JOIN','page_latest=rev_id') )
 971          * @return mixed Database result resource (feed to Database::fetchObject or whatever), or false on failure
 972          */
 973         function select( $table, $vars, $conds='', $fname = 'Database::select', $options = array(), $join_conds = array() )
 974         {
 975                 $sql = $this->selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 976                 return $this->query( $sql, $fname );
 977         }
 978
 979         /**
 980          * SELECT wrapper
 981          *
 982          * @param mixed  $table   Array or string, table name(s) (prefix auto-added)
 983          * @param mixed  $vars    Array or string, field name(s) to be retrieved
 984          * @param mixed  $conds   Array or string, condition(s) for WHERE
 985          * @param string $fname   Calling function name (use __METHOD__) for logs/profiling
 986          * @param array  $options Associative array of options (e.g. array('GROUP BY' => 'page_title')),
 987          *                        see Database::makeSelectOptions code for list of supported stuff
 988          * @param array $join_conds Associative array of table join conditions (optional)
 989          *                        (e.g. array( 'page' => array('LEFT JOIN','page_latest=rev_id') )
 990          * @return string, the SQL text
 991          */
 992         function selectSQLText( $table, $vars, $conds='', $fname = 'Database::select', $options = array(), $join_conds = array() ) {
 993                 if( is_array( $vars ) ) {
 994                         $vars = implode( ',', $vars );
 995                 }
 996                 if( !is_array( $options ) ) {
 997                         $options = array( $options );
 998                 }
 999                 if( is_array( $table ) ) {
1000                         if ( !empty($join_conds) || ( isset( $options['USE INDEX'] ) && is_array( @$options['USE INDEX'] ) ) )
1001                                 $from = ' FROM ' . $this->tableNamesWithUseIndexOrJOIN( $table, @$options['USE INDEX'], $join_conds );
1002                         else
1003                                 $from = ' FROM ' . implode( ',', array_map( array( &$this, 'tableName' ), $table ) );
1004                 } elseif ($table!='') {
1005                         if ($table{0}==' ') {
1006                                 $from = ' FROM ' . $table;
1007                         } else {
1008                                 $from = ' FROM ' . $this->tableName( $table );
1009                         }
1010                 } else {
1011                         $from = '';
1012                 }
1013
1014                 list( $startOpts, $useIndex, $preLimitTail, $postLimitTail ) = $this->makeSelectOptions( $options );
1015
1016                 if( !empty( $conds ) ) {
1017                         if ( is_array( $conds ) ) {
1018                                 $conds = $this->makeList( $conds, LIST_AND );
1019                         }
1020                         $sql = "SELECT $startOpts $vars $from $useIndex WHERE $conds $preLimitTail";
1021                 } else {
1022                         $sql = "SELECT $startOpts $vars $from $useIndex $preLimitTail";
1023                 }
1024
1025                 if (isset($options['LIMIT']))
1026                         $sql = $this->limitResult($sql, $options['LIMIT'],
1027                                 isset($options['OFFSET']) ? $options['OFFSET'] : false);
1028                 $sql = "$sql $postLimitTail";
1029
1030                 if (isset($options['EXPLAIN'])) {
1031                         $sql = 'EXPLAIN ' . $sql;
1032                 }
1033                 return $sql;
1034         }
1035
1036         /**
1037          * Single row SELECT wrapper
1038          * Aborts or returns FALSE on error
1039          *
1040          * $vars: the selected variables
1041          * $conds: a condition map, terms are ANDed together.
1042          *   Items with numeric keys are taken to be literal conditions
1043          * Takes an array of selected variables, and a condition map, which is ANDed
1044          * e.g: selectRow( "page", array( "page_id" ), array( "page_namespace" =>
1045          * NS_MAIN, "page_title" => "Astronomy" ) )   would return an object where
1046          * $obj- >page_id is the ID of the Astronomy article
1047          *
1048          * @todo migrate documentation to phpdocumentor format
1049          */
1050         function selectRow( $table, $vars, $conds, $fname = 'Database::selectRow', $options = array(), $join_conds = array() ) {
1051                 $options['LIMIT'] = 1;
1052                 $res = $this->select( $table, $vars, $conds, $fname, $options, $join_conds );
1053                 if ( $res === false )
1054                         return false;
1055                 if ( !$this->numRows($res) ) {
1056                         $this->freeResult($res);
1057                         return false;
1058                 }
1059                 $obj = $this->fetchObject( $res );
1060                 $this->freeResult( $res );
1061                 return $obj;
1062
1063         }
1064
1065         /**
1066          * Estimate rows in dataset
1067          * Returns estimated count, based on EXPLAIN output
1068          * Takes same arguments as Database::select()
1069          */
1070
1071         function estimateRowCount( $table, $vars='*', $conds='', $fname = 'Database::estimateRowCount', $options = array() ) {
1072                 $options['EXPLAIN']=true;
1073                 $res = $this->select ($table, $vars, $conds, $fname, $options );
1074                 if ( $res === false )
1075                         return false;
1076                 if (!$this->numRows($res)) {
1077                         $this->freeResult($res);
1078                         return 0;
1079                 }
1080
1081                 $rows=1;
1082
1083                 while( $plan = $this->fetchObject( $res ) ) {
1084                         $rows *= ($plan->rows > 0)?$plan->rows:1; // avoid resetting to zero
1085                 }
1086
1087                 $this->freeResult($res);
1088                 return $rows;
1089         }
1090
1091
1092         /**
1093          * Removes most variables from an SQL query and replaces them with X or N for numbers.
1094          * It's only slightly flawed. Don't use for anything important.
1095          *
1096          * @param string $sql A SQL Query
1097          * @static
1098          */
1099         static function generalizeSQL( $sql ) {
1100                 # This does the same as the regexp below would do, but in such a way
1101                 # as to avoid crashing php on some large strings.
1102                 # $sql = preg_replace ( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql);
1103
1104                 $sql = str_replace ( "\\\\", '', $sql);
1105                 $sql = str_replace ( "\\'", '', $sql);
1106                 $sql = str_replace ( "\\\"", '', $sql);
1107                 $sql = preg_replace ("/'.*'/s", "'X'", $sql);
1108                 $sql = preg_replace ('/".*"/s', "'X'", $sql);
1109
1110                 # All newlines, tabs, etc replaced by single space
1111                 $sql = preg_replace ( '/\s+/', ' ', $sql);
1112
1113                 # All numbers => N
1114                 $sql = preg_replace ('/-?[0-9]+/s', 'N', $sql);
1115
1116                 return $sql;
1117         }
1118
1119         /**
1120          * Determines whether a field exists in a table
1121          * Usually aborts on failure
1122          * If errors are explicitly ignored, returns NULL on failure
1123          */
1124         function fieldExists( $table, $field, $fname = 'Database::fieldExists' ) {
1125                 $table = $this->tableName( $table );
1126                 $res = $this->query( 'DESCRIBE '.$table, $fname );
1127                 if ( !$res ) {
1128                         return NULL;
1129                 }
1130
1131                 $found = false;
1132
1133                 while ( $row = $this->fetchObject( $res ) ) {
1134                         if ( $row->Field == $field ) {
1135                                 $found = true;
1136                                 break;
1137                         }
1138                 }
1139                 return $found;
1140         }
1141
1142         /**
1143          * Determines whether an index exists
1144          * Usually aborts on failure
1145          * If errors are explicitly ignored, returns NULL on failure
1146          */
1147         function indexExists( $table, $index, $fname = 'Database::indexExists' ) {
1148                 $info = $this->indexInfo( $table, $index, $fname );
1149                 if ( is_null( $info ) ) {
1150                         return NULL;
1151                 } else {
1152                         return $info !== false;
1153                 }
1154         }
1155
1156
1157         /**
1158          * Get information about an index into an object
1159          * Returns false if the index does not exist
1160          */
1161         function indexInfo( $table, $index, $fname = 'Database::indexInfo' ) {
1162                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
1163                 # SHOW INDEX should work for 3.x and up:
1164                 # http://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
1165                 $table = $this->tableName( $table );
1166                 $sql = 'SHOW INDEX FROM '.$table;
1167                 $res = $this->query( $sql, $fname );
1168                 if ( !$res ) {
1169                         return NULL;
1170                 }
1171
1172                 $result = array();
1173                 while ( $row = $this->fetchObject( $res ) ) {
1174                         if ( $row->Key_name == $index ) {
1175                                 $result[] = $row;
1176                         }
1177                 }
1178                 $this->freeResult($res);
1179
1180                 return empty($result) ? false : $result;
1181         }
1182
1183         /**
1184          * Query whether a given table exists
1185          */
1186         function tableExists( $table ) {
1187                 $table = $this->tableName( $table );
1188                 $old = $this->ignoreErrors( true );
1189                 $res = $this->query( "SELECT 1 FROM $table LIMIT 1" );
1190                 $this->ignoreErrors( $old );
1191                 if( $res ) {
1192                         $this->freeResult( $res );
1193                         return true;
1194                 } else {
1195                         return false;
1196                 }
1197         }
1198
1199         /**
1200          * mysql_fetch_field() wrapper
1201          * Returns false if the field doesn't exist
1202          *
1203          * @param $table
1204          * @param $field
1205          */
1206         function fieldInfo( $table, $field ) {
1207                 $table = $this->tableName( $table );
1208                 $res = $this->query( "SELECT * FROM $table LIMIT 1" );
1209                 $n = mysql_num_fields( $res->result );
1210                 for( $i = 0; $i < $n; $i++ ) {
1211                         $meta = mysql_fetch_field( $res->result, $i );
1212                         if( $field == $meta->name ) {
1213                                 return new MySQLField($meta);
1214                         }
1215                 }
1216                 return false;
1217         }
1218
1219         /**
1220          * mysql_field_type() wrapper
1221          */
1222         function fieldType( $res, $index ) {
1223                 if ( $res instanceof ResultWrapper ) {
1224                         $res = $res->result;
1225                 }
1226                 return mysql_field_type( $res, $index );
1227         }
1228
1229         /**
1230          * Determines if a given index is unique
1231          */
1232         function indexUnique( $table, $index ) {
1233                 $indexInfo = $this->indexInfo( $table, $index );
1234                 if ( !$indexInfo ) {
1235                         return NULL;
1236                 }
1237                 return !$indexInfo[0]->Non_unique;
1238         }
1239
1240         /**
1241          * INSERT wrapper, inserts an array into a table
1242          *
1243          * $a may be a single associative array, or an array of these with numeric keys, for
1244          * multi-row insert.
1245          *
1246          * Usually aborts on failure
1247          * If errors are explicitly ignored, returns success
1248          */
1249         function insert( $table, $a, $fname = 'Database::insert', $options = array() ) {
1250                 # No rows to insert, easy just return now
1251                 if ( !count( $a ) ) {
1252                         return true;
1253                 }
1254
1255                 $table = $this->tableName( $table );
1256                 if ( !is_array( $options ) ) {
1257                         $options = array( $options );
1258                 }
1259                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
1260                         $multi = true;
1261                         $keys = array_keys( $a[0] );
1262                 } else {
1263                         $multi = false;
1264                         $keys = array_keys( $a );
1265                 }
1266
1267                 $sql = 'INSERT ' . implode( ' ', $options ) .
1268                         " INTO $table (" . implode( ',', $keys ) . ') VALUES ';
1269
1270                 if ( $multi ) {
1271                         $first = true;
1272                         foreach ( $a as $row ) {
1273                                 if ( $first ) {
1274                                         $first = false;
1275                                 } else {
1276                                         $sql .= ',';
1277                                 }
1278                                 $sql .= '(' . $this->makeList( $row ) . ')';
1279                         }
1280                 } else {
1281                         $sql .= '(' . $this->makeList( $a ) . ')';
1282                 }
1283                 return (bool)$this->query( $sql, $fname );
1284         }
1285
1286         /**
1287          * Make UPDATE options for the Database::update function
1288          *
1289          * @private
1290          * @param array $options The options passed to Database::update
1291          * @return string
1292          */
1293         function makeUpdateOptions( $options ) {
1294                 if( !is_array( $options ) ) {
1295                         $options = array( $options );
1296                 }
1297                 $opts = array();
1298                 if ( in_array( 'LOW_PRIORITY', $options ) )
1299                         $opts[] = $this->lowPriorityOption();
1300                 if ( in_array( 'IGNORE', $options ) )
1301                         $opts[] = 'IGNORE';
1302                 return implode(' ', $opts);
1303         }
1304
1305         /**
1306          * UPDATE wrapper, takes a condition array and a SET array
1307          *
1308          * @param string $table  The table to UPDATE
1309          * @param array  $values An array of values to SET
1310          * @param array  $conds  An array of conditions (WHERE). Use '*' to update all rows.
1311          * @param string $fname  The Class::Function calling this function
1312          *                       (for the log)
1313          * @param array  $options An array of UPDATE options, can be one or
1314          *                        more of IGNORE, LOW_PRIORITY
1315          * @return bool
1316          */
1317         function update( $table, $values, $conds, $fname = 'Database::update', $options = array() ) {
1318                 $table = $this->tableName( $table );
1319                 $opts = $this->makeUpdateOptions( $options );
1320                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET );
1321                 if ( $conds != '*' ) {
1322                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1323                 }
1324                 return $this->query( $sql, $fname );
1325         }
1326
1327         /**
1328          * Makes an encoded list of strings from an array
1329          * $mode:
1330          *        LIST_COMMA         - comma separated, no field names
1331          *        LIST_AND           - ANDed WHERE clause (without the WHERE)
1332          *        LIST_OR            - ORed WHERE clause (without the WHERE)
1333          *        LIST_SET           - comma separated with field names, like a SET clause
1334          *        LIST_NAMES         - comma separated field names
1335          */
1336         function makeList( $a, $mode = LIST_COMMA ) {
1337                 if ( !is_array( $a ) ) {
1338                         throw new DBUnexpectedError( $this, 'Database::makeList called with incorrect parameters' );
1339                 }
1340
1341                 $first = true;
1342                 $list = '';
1343                 foreach ( $a as $field => $value ) {
1344                         if ( !$first ) {
1345                                 if ( $mode == LIST_AND ) {
1346                                         $list .= ' AND ';
1347                                 } elseif($mode == LIST_OR) {
1348                                         $list .= ' OR ';
1349                                 } else {
1350                                         $list .= ',';
1351                                 }
1352                         } else {
1353                                 $first = false;
1354                         }
1355                         if ( ($mode == LIST_AND || $mode == LIST_OR) && is_numeric( $field ) ) {
1356                                 $list .= "($value)";
1357                         } elseif ( ($mode == LIST_SET) && is_numeric( $field ) ) {
1358                                 $list .= "$value";
1359                         } elseif ( ($mode == LIST_AND || $mode == LIST_OR) && is_array($value) ) {
1360                                 if( count( $value ) == 0 ) {
1361                                         throw new MWException( __METHOD__.': empty input' );
1362                                 } elseif( count( $value ) == 1 ) {
1363                                         // Special-case single values, as IN isn't terribly efficient
1364                                         // Don't necessarily assume the single key is 0; we don't
1365                                         // enforce linear numeric ordering on other arrays here.
1366                                         $value = array_values( $value );
1367                                         $list .= $field." = ".$this->addQuotes( $value[0] );
1368                                 } else {
1369                                         $list .= $field." IN (".$this->makeList($value).") ";
1370                                 }
1371                         } elseif( is_null($value) ) {
1372                                 if ( $mode == LIST_AND || $mode == LIST_OR ) {
1373                                         $list .= "$field IS ";
1374                                 } elseif ( $mode == LIST_SET ) {
1375                                         $list .= "$field = ";
1376                                 }
1377                                 $list .= 'NULL';
1378                         } else {
1379                                 if ( $mode == LIST_AND || $mode == LIST_OR || $mode == LIST_SET ) {
1380                                         $list .= "$field = ";
1381                                 }
1382                                 $list .= $mode == LIST_NAMES ? $value : $this->addQuotes( $value );
1383                         }
1384                 }
1385                 return $list;
1386         }
1387
1388         /**
1389          * Change the current database
1390          */
1391         function selectDB( $db ) {
1392                 $this->mDBname = $db;
1393                 return mysql_select_db( $db, $this->mConn );
1394         }
1395
1396         /**
1397          * Get the current DB name
1398          */
1399         function getDBname() {
1400                 return $this->mDBname;
1401         }
1402
1403         /**
1404          * Get the server hostname or IP address
1405          */
1406         function getServer() {
1407                 return $this->mServer;
1408         }
1409
1410         /**
1411          * Format a table name ready for use in constructing an SQL query
1412          *
1413          * This does two important things: it quotes the table names to clean them up,
1414          * and it adds a table prefix if only given a table name with no quotes.
1415          *
1416          * All functions of this object which require a table name call this function
1417          * themselves. Pass the canonical name to such functions. This is only needed
1418          * when calling query() directly.
1419          *
1420          * @param string $name database table name
1421          * @return string full database name
1422          */
1423         function tableName( $name ) {
1424                 global $wgSharedDB, $wgSharedPrefix, $wgSharedTables;
1425                 # Skip the entire process when we have a string quoted on both ends.
1426                 # Note that we check the end so that we will still quote any use of
1427                 # use of `database`.table. But won't break things if someone wants
1428                 # to query a database table with a dot in the name.
1429                 if ( $name[0] == '`' && substr( $name, -1, 1 ) == '`' ) return $name;
1430
1431                 # Lets test for any bits of text that should never show up in a table
1432                 # name. Basically anything like JOIN or ON which are actually part of
1433                 # SQL queries, but may end up inside of the table value to combine
1434                 # sql. Such as how the API is doing.
1435                 # Note that we use a whitespace test rather than a \b test to avoid
1436                 # any remote case where a word like on may be inside of a table name
1437                 # surrounded by symbols which may be considered word breaks.
1438                 if( preg_match( '/(^|\s)(DISTINCT|JOIN|ON|AS)(\s|$)/i', $name ) !== 0 ) return $name;
1439
1440                 # Split database and table into proper variables.
1441                 # We reverse the explode so that database.table and table both output
1442                 # the correct table.
1443                 $dbDetails = array_reverse( explode( '.', $name, 2 ) );
1444                 if( isset( $dbDetails[1] ) ) @list( $table, $database ) = $dbDetails;
1445                 else                         @list( $table ) = $dbDetails;
1446                 $prefix = $this->mTablePrefix; # Default prefix
1447
1448                 # A database name has been specified in input. Quote the table name
1449                 # because we don't want any prefixes added.
1450                 if( isset($database) ) $table = ( $table[0] == '`' ? $table : "`{$table}`" );
1451
1452                 # Note that we use the long format because php will complain in in_array if
1453                 # the input is not an array, and will complain in is_array if it is not set.
1454                 if( !isset( $database ) # Don't use shared database if pre selected.
1455                  && isset( $wgSharedDB ) # We have a shared database
1456                  && $table[0] != '`' # Paranoia check to prevent shared tables listing '`table`'
1457                  && isset( $wgSharedTables )
1458                  && is_array( $wgSharedTables )
1459                  && in_array( $table, $wgSharedTables ) ) { # A shared table is selected
1460                         $database = $wgSharedDB;
1461                         $prefix   = isset( $wgSharedPrefix ) ? $wgSharedPrefix : $prefix;
1462                 }
1463
1464                 # Quote the $database and $table and apply the prefix if not quoted.
1465                 if( isset($database) ) $database = ( $database[0] == '`' ? $database : "`{$database}`" );
1466                 $table = ( $table[0] == '`' ? $table : "`{$prefix}{$table}`" );
1467
1468                 # Merge our database and table into our final table name.
1469                 $tableName = ( isset($database) ? "{$database}.{$table}" : "{$table}" );
1470
1471                 # We're finished, return.
1472                 return $tableName;
1473         }
1474
1475         /**
1476          * Fetch a number of table names into an array
1477          * This is handy when you need to construct SQL for joins
1478          *
1479          * Example:
1480          * extract($dbr->tableNames('user','watchlist'));
1481          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1482          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1483          */
1484         public function tableNames() {
1485                 $inArray = func_get_args();
1486                 $retVal = array();
1487                 foreach ( $inArray as $name ) {
1488                         $retVal[$name] = $this->tableName( $name );
1489                 }
1490                 return $retVal;
1491         }
1492
1493         /**
1494          * Fetch a number of table names into an zero-indexed numerical array
1495          * This is handy when you need to construct SQL for joins
1496          *
1497          * Example:
1498          * list( $user, $watchlist ) = $dbr->tableNamesN('user','watchlist');
1499          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1500          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1501          */
1502         public function tableNamesN() {
1503                 $inArray = func_get_args();
1504                 $retVal = array();
1505                 foreach ( $inArray as $name ) {
1506                         $retVal[] = $this->tableName( $name );
1507                 }
1508                 return $retVal;
1509         }
1510
1511         /**
1512          * @private
1513          */
1514         function tableNamesWithUseIndexOrJOIN( $tables, $use_index = array(), $join_conds = array() ) {
1515                 $ret = array();
1516                 $retJOIN = array();
1517                 $use_index_safe = is_array($use_index) ? $use_index : array();
1518                 $join_conds_safe = is_array($join_conds) ? $join_conds : array();
1519                 foreach ( $tables as $table ) {
1520                         // Is there a JOIN and INDEX clause for this table?
1521                         if ( isset($join_conds_safe[$table]) && isset($use_index_safe[$table]) ) {
1522                                 $tableClause = $join_conds_safe[$table][0] . ' ' . $this->tableName( $table );
1523                                 $tableClause .= ' ' . $this->useIndexClause( implode( ',', (array)$use_index_safe[$table] ) );
1524                                 $tableClause .= ' ON (' . $this->makeList((array)$join_conds_safe[$table][1], LIST_AND) . ')';
1525                                 $retJOIN[] = $tableClause;
1526                         // Is there an INDEX clause?
1527                         } else if ( isset($use_index_safe[$table]) ) {
1528                                 $tableClause = $this->tableName( $table );
1529                                 $tableClause .= ' ' . $this->useIndexClause( implode( ',', (array)$use_index_safe[$table] ) );
1530                                 $ret[] = $tableClause;
1531                         // Is there a JOIN clause?
1532                         } else if ( isset($join_conds_safe[$table]) ) {
1533                                 $tableClause = $join_conds_safe[$table][0] . ' ' . $this->tableName( $table );
1534                                 $tableClause .= ' ON (' . $this->makeList((array)$join_conds_safe[$table][1], LIST_AND) . ')';
1535                                 $retJOIN[] = $tableClause;
1536                         } else {
1537                                 $tableClause = $this->tableName( $table );
1538                                 $ret[] = $tableClause;
1539                         }
1540                 }
1541                 // We can't separate explicit JOIN clauses with ',', use ' ' for those
1542                 $straightJoins = !empty($ret) ? implode( ',', $ret ) : "";
1543                 $otherJoins = !empty($retJOIN) ? implode( ' ', $retJOIN ) : "";
1544                 // Compile our final table clause
1545                 return implode(' ',array($straightJoins,$otherJoins) );
1546         }
1547
1548         /**
1549          * Wrapper for addslashes()
1550          * @param string $s String to be slashed.
1551          * @return string slashed string.
1552          */
1553         function strencode( $s ) {
1554                 return mysql_real_escape_string( $s, $this->mConn );
1555         }
1556
1557         /**
1558          * If it's a string, adds quotes and backslashes
1559          * Otherwise returns as-is
1560          */
1561         function addQuotes( $s ) {
1562                 if ( is_null( $s ) ) {
1563                         return 'NULL';
1564                 } else {
1565                         # This will also quote numeric values. This should be harmless,
1566                         # and protects against weird problems that occur when they really
1567                         # _are_ strings such as article titles and string->number->string
1568                         # conversion is not 1:1.
1569                         return "'" . $this->strencode( $s ) . "'";
1570                 }
1571         }
1572
1573         /**
1574          * Escape string for safe LIKE usage
1575          */
1576         function escapeLike( $s ) {
1577                 $s=$this->strencode( $s );
1578                 $s=str_replace(array('%','_'),array('\%','\_'),$s);
1579                 return $s;
1580         }
1581
1582         /**
1583          * Returns an appropriately quoted sequence value for inserting a new row.
1584          * MySQL has autoincrement fields, so this is just NULL. But the PostgreSQL
1585          * subclass will return an integer, and save the value for insertId()
1586          */
1587         function nextSequenceValue( $seqName ) {
1588                 return NULL;
1589         }
1590
1591         /**
1592          * USE INDEX clause
1593          * PostgreSQL doesn't have them and returns ""
1594          */
1595         function useIndexClause( $index ) {
1596                 return "FORCE INDEX ($index)";
1597         }
1598
1599         /**
1600          * REPLACE query wrapper
1601          * PostgreSQL simulates this with a DELETE followed by INSERT
1602          * $row is the row to insert, an associative array
1603          * $uniqueIndexes is an array of indexes. Each element may be either a
1604          * field name or an array of field names
1605          *
1606          * It may be more efficient to leave off unique indexes which are unlikely to collide.
1607          * However if you do this, you run the risk of encountering errors which wouldn't have
1608          * occurred in MySQL
1609          *
1610          * @todo migrate comment to phodocumentor format
1611          */
1612         function replace( $table, $uniqueIndexes, $rows, $fname = 'Database::replace' ) {
1613                 $table = $this->tableName( $table );
1614
1615                 # Single row case
1616                 if ( !is_array( reset( $rows ) ) ) {
1617                         $rows = array( $rows );
1618                 }
1619
1620                 $sql = "REPLACE INTO $table (" . implode( ',', array_keys( $rows[0] ) ) .') VALUES ';
1621                 $first = true;
1622                 foreach ( $rows as $row ) {
1623                         if ( $first ) {
1624                                 $first = false;
1625                         } else {
1626                                 $sql .= ',';
1627                         }
1628                         $sql .= '(' . $this->makeList( $row ) . ')';
1629                 }
1630                 return $this->query( $sql, $fname );
1631         }
1632
1633         /**
1634          * DELETE where the condition is a join
1635          * MySQL does this with a multi-table DELETE syntax, PostgreSQL does it with sub-selects
1636          *
1637          * For safety, an empty $conds will not delete everything. If you want to delete all rows where the
1638          * join condition matches, set $conds='*'
1639          *
1640          * DO NOT put the join condition in $conds
1641          *
1642          * @param string $delTable The table to delete from.
1643          * @param string $joinTable The other table.
1644          * @param string $delVar The variable to join on, in the first table.
1645          * @param string $joinVar The variable to join on, in the second table.
1646          * @param array $conds Condition array of field names mapped to variables, ANDed together in the WHERE clause
1647          */
1648         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = 'Database::deleteJoin' ) {
1649                 if ( !$conds ) {
1650                         throw new DBUnexpectedError( $this, 'Database::deleteJoin() called with empty $conds' );
1651                 }
1652
1653                 $delTable = $this->tableName( $delTable );
1654                 $joinTable = $this->tableName( $joinTable );
1655                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
1656                 if ( $conds != '*' ) {
1657                         $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
1658                 }
1659
1660                 return $this->query( $sql, $fname );
1661         }
1662
1663         /**
1664          * Returns the size of a text field, or -1 for "unlimited"
1665          */
1666         function textFieldSize( $table, $field ) {
1667                 $table = $this->tableName( $table );
1668                 $sql = "SHOW COLUMNS FROM $table LIKE \"$field\";";
1669                 $res = $this->query( $sql, 'Database::textFieldSize' );
1670                 $row = $this->fetchObject( $res );
1671                 $this->freeResult( $res );
1672
1673                 $m = array();
1674                 if ( preg_match( '/\((.*)\)/', $row->Type, $m ) ) {
1675                         $size = $m[1];
1676                 } else {
1677                         $size = -1;
1678                 }
1679                 return $size;
1680         }
1681
1682         /**
1683          * @return string Returns the text of the low priority option if it is supported, or a blank string otherwise
1684          */
1685         function lowPriorityOption() {
1686                 return 'LOW_PRIORITY';
1687         }
1688
1689         /**
1690          * DELETE query wrapper
1691          *
1692          * Use $conds == "*" to delete all rows
1693          */
1694         function delete( $table, $conds, $fname = 'Database::delete' ) {
1695                 if ( !$conds ) {
1696                         throw new DBUnexpectedError( $this, 'Database::delete() called with no conditions' );
1697                 }
1698                 $table = $this->tableName( $table );
1699                 $sql = "DELETE FROM $table";
1700                 if ( $conds != '*' ) {
1701                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1702                 }
1703                 return $this->query( $sql, $fname );
1704         }
1705
1706         /**
1707          * INSERT SELECT wrapper
1708          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
1709          * Source items may be literals rather than field names, but strings should be quoted with Database::addQuotes()
1710          * $conds may be "*" to copy the whole table
1711          * srcTable may be an array of tables.
1712          */
1713         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'Database::insertSelect',
1714                 $insertOptions = array(), $selectOptions = array() )
1715         {
1716                 $destTable = $this->tableName( $destTable );
1717                 if ( is_array( $insertOptions ) ) {
1718                         $insertOptions = implode( ' ', $insertOptions );
1719                 }
1720                 if( !is_array( $selectOptions ) ) {
1721                         $selectOptions = array( $selectOptions );
1722                 }
1723                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
1724                 if( is_array( $srcTable ) ) {
1725                         $srcTable =  implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
1726                 } else {
1727                         $srcTable = $this->tableName( $srcTable );
1728                 }
1729                 $sql = "INSERT $insertOptions INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
1730                         " SELECT $startOpts " . implode( ',', $varMap ) .
1731                         " FROM $srcTable $useIndex ";
1732                 if ( $conds != '*' ) {
1733                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1734                 }
1735                 $sql .= " $tailOpts";
1736                 return $this->query( $sql, $fname );
1737         }
1738
1739         /**
1740          * Construct a LIMIT query with optional offset
1741          * This is used for query pages
1742          * $sql string SQL query we will append the limit too
1743          * $limit integer the SQL limit
1744          * $offset integer the SQL offset (default false)
1745          */
1746         function limitResult($sql, $limit, $offset=false) {
1747                 if( !is_numeric($limit) ) {
1748                         throw new DBUnexpectedError( $this, "Invalid non-numeric limit passed to limitResult()\n" );
1749                 }
1750                 return "$sql LIMIT "
1751                                 . ( (is_numeric($offset) && $offset != 0) ? "{$offset}," : "" )
1752                                 . "{$limit} ";
1753         }
1754         function limitResultForUpdate($sql, $num) {
1755                 return $this->limitResult($sql, $num, 0);
1756         }
1757
1758         /**
1759          * Returns an SQL expression for a simple conditional.
1760          * Uses IF on MySQL.
1761          *
1762          * @param string $cond SQL expression which will result in a boolean value
1763          * @param string $trueVal SQL expression to return if true
1764          * @param string $falseVal SQL expression to return if false
1765          * @return string SQL fragment
1766          */
1767         function conditional( $cond, $trueVal, $falseVal ) {
1768                 return " IF($cond, $trueVal, $falseVal) ";
1769         }
1770
1771         /**
1772          * Returns a comand for str_replace function in SQL query.
1773          * Uses REPLACE() in MySQL
1774          *
1775          * @param string $orig String or column to modify
1776          * @param string $old String or column to seek
1777          * @param string $new String or column to replace with
1778          */
1779         function strreplace( $orig, $old, $new ) {
1780                 return "REPLACE({$orig}, {$old}, {$new})";
1781         }
1782
1783         /**
1784          * Determines if the last failure was due to a deadlock
1785          */
1786         function wasDeadlock() {
1787                 return $this->lastErrno() == 1213;
1788         }
1789
1790         /**
1791          * Perform a deadlock-prone transaction.
1792          *
1793          * This function invokes a callback function to perform a set of write
1794          * queries. If a deadlock occurs during the processing, the transaction
1795          * will be rolled back and the callback function will be called again.
1796          *
1797          * Usage:
1798          *   $dbw->deadlockLoop( callback, ... );
1799          *
1800          * Extra arguments are passed through to the specified callback function.
1801          *
1802          * Returns whatever the callback function returned on its successful,
1803          * iteration, or false on error, for example if the retry limit was
1804          * reached.
1805          */
1806         function deadlockLoop() {
1807                 $myFname = 'Database::deadlockLoop';
1808
1809                 $this->begin();
1810                 $args = func_get_args();
1811                 $function = array_shift( $args );
1812                 $oldIgnore = $this->ignoreErrors( true );
1813                 $tries = DEADLOCK_TRIES;
1814                 if ( is_array( $function ) ) {
1815                         $fname = $function[0];
1816                 } else {
1817                         $fname = $function;
1818                 }
1819                 do {
1820                         $retVal = call_user_func_array( $function, $args );
1821                         $error = $this->lastError();
1822                         $errno = $this->lastErrno();
1823                         $sql = $this->lastQuery();
1824
1825                         if ( $errno ) {
1826                                 if ( $this->wasDeadlock() ) {
1827                                         # Retry
1828                                         usleep( mt_rand( DEADLOCK_DELAY_MIN, DEADLOCK_DELAY_MAX ) );
1829                                 } else {
1830                                         $this->reportQueryError( $error, $errno, $sql, $fname );
1831                                 }
1832                         }
1833                 } while( $this->wasDeadlock() && --$tries > 0 );
1834                 $this->ignoreErrors( $oldIgnore );
1835                 if ( $tries <= 0 ) {
1836                         $this->query( 'ROLLBACK', $myFname );
1837                         $this->reportQueryError( $error, $errno, $sql, $fname );
1838                         return false;
1839                 } else {
1840                         $this->query( 'COMMIT', $myFname );
1841                         return $retVal;
1842                 }
1843         }
1844
1845         /**
1846          * Do a SELECT MASTER_POS_WAIT()
1847          *
1848          * @param string $file the binlog file
1849          * @param string $pos the binlog position
1850          * @param integer $timeout the maximum number of seconds to wait for synchronisation
1851          */
1852         function masterPosWait( MySQLMasterPos $pos, $timeout ) {
1853                 $fname = 'Database::masterPosWait';
1854                 wfProfileIn( $fname );
1855
1856                 # Commit any open transactions
1857                 if ( $this->mTrxLevel ) {
1858                         $this->immediateCommit();
1859                 }
1860
1861                 if ( !is_null( $this->mFakeSlaveLag ) ) {
1862                         $wait = intval( ( $pos->pos - microtime(true) + $this->mFakeSlaveLag ) * 1e6 );
1863                         if ( $wait > $timeout * 1e6 ) {
1864                                 wfDebug( "Fake slave timed out waiting for $pos ($wait us)\n" );
1865                                 wfProfileOut( $fname );
1866                                 return -1;
1867                         } elseif ( $wait > 0 ) {
1868                                 wfDebug( "Fake slave waiting $wait us\n" );
1869                                 usleep( $wait );
1870                                 wfProfileOut( $fname );
1871                                 return 1;
1872                         } else {
1873                                 wfDebug( "Fake slave up to date ($wait us)\n" );
1874                                 wfProfileOut( $fname );
1875                                 return 0;
1876                         }
1877                 }
1878
1879                 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
1880                 $encFile = $this->addQuotes( $pos->file );
1881                 $encPos = intval( $pos->pos );
1882                 $sql = "SELECT MASTER_POS_WAIT($encFile, $encPos, $timeout)";
1883                 $res = $this->doQuery( $sql );
1884                 if ( $res && $row = $this->fetchRow( $res ) ) {
1885                         $this->freeResult( $res );
1886                         wfProfileOut( $fname );
1887                         return $row[0];
1888                 } else {
1889                         wfProfileOut( $fname );
1890                         return false;
1891                 }
1892         }
1893
1894         /**
1895          * Get the position of the master from SHOW SLAVE STATUS
1896          */
1897         function getSlavePos() {
1898                 if ( !is_null( $this->mFakeSlaveLag ) ) {
1899                         $pos = new MySQLMasterPos( 'fake', microtime(true) - $this->mFakeSlaveLag );
1900                         wfDebug( __METHOD__.": fake slave pos = $pos\n" );
1901                         return $pos;
1902                 }
1903                 $res = $this->query( 'SHOW SLAVE STATUS', 'Database::getSlavePos' );
1904                 $row = $this->fetchObject( $res );
1905                 if ( $row ) {
1906                         return new MySQLMasterPos( $row->Master_Log_File, $row->Read_Master_Log_Pos );
1907                 } else {
1908                         return false;
1909                 }
1910         }
1911
1912         /**
1913          * Get the position of the master from SHOW MASTER STATUS
1914          */
1915         function getMasterPos() {
1916                 if ( $this->mFakeMaster ) {
1917                         return new MySQLMasterPos( 'fake', microtime( true ) );
1918                 }
1919                 $res = $this->query( 'SHOW MASTER STATUS', 'Database::getMasterPos' );
1920                 $row = $this->fetchObject( $res );
1921                 if ( $row ) {
1922                         return new MySQLMasterPos( $row->File, $row->Position );
1923                 } else {
1924                         return false;
1925                 }
1926         }
1927
1928         /**
1929          * Begin a transaction, committing any previously open transaction
1930          */
1931         function begin( $fname = 'Database::begin' ) {
1932                 $this->query( 'BEGIN', $fname );
1933                 $this->mTrxLevel = 1;
1934         }
1935
1936         /**
1937          * End a transaction
1938          */
1939         function commit( $fname = 'Database::commit' ) {
1940                 $this->query( 'COMMIT', $fname );
1941                 $this->mTrxLevel = 0;
1942         }
1943
1944         /**
1945          * Rollback a transaction.
1946          * No-op on non-transactional databases.
1947          */
1948         function rollback( $fname = 'Database::rollback' ) {
1949                 $this->query( 'ROLLBACK', $fname, true );
1950                 $this->mTrxLevel = 0;
1951         }
1952
1953         /**
1954          * Begin a transaction, committing any previously open transaction
1955          * @deprecated use begin()
1956          */
1957         function immediateBegin( $fname = 'Database::immediateBegin' ) {
1958                 $this->begin();
1959         }
1960
1961         /**
1962          * Commit transaction, if one is open
1963          * @deprecated use commit()
1964          */
1965         function immediateCommit( $fname = 'Database::immediateCommit' ) {
1966                 $this->commit();
1967         }
1968
1969         /**
1970          * Return MW-style timestamp used for MySQL schema
1971          */
1972         function timestamp( $ts=0 ) {
1973                 return wfTimestamp(TS_MW,$ts);
1974         }
1975
1976         /**
1977          * Local database timestamp format or null
1978          */
1979         function timestampOrNull( $ts = null ) {
1980                 if( is_null( $ts ) ) {
1981                         return null;
1982                 } else {
1983                         return $this->timestamp( $ts );
1984                 }
1985         }
1986
1987         /**
1988          * @todo document
1989          */
1990         function resultObject( $result ) {
1991                 if( empty( $result ) ) {
1992                         return false;
1993                 } elseif ( $result instanceof ResultWrapper ) {
1994                         return $result;
1995                 } elseif ( $result === true ) {
1996                         // Successful write query
1997                         return $result;
1998                 } else {
1999                         return new ResultWrapper( $this, $result );
2000                 }
2001         }
2002
2003         /**
2004          * Return aggregated value alias
2005          */
2006         function aggregateValue ($valuedata,$valuename='value') {
2007                 return $valuename;
2008         }
2009
2010         /**
2011          * @return string wikitext of a link to the server software's web site
2012          */
2013         function getSoftwareLink() {
2014                 return "[http://www.mysql.com/ MySQL]";
2015         }
2016
2017         /**
2018          * @return string Version information from the database
2019          */
2020         function getServerVersion() {
2021                 return mysql_get_server_info( $this->mConn );
2022         }
2023
2024         /**
2025          * Ping the server and try to reconnect if it there is no connection
2026          */
2027         function ping() {
2028                 if( !function_exists( 'mysql_ping' ) ) {
2029                         wfDebug( "Tried to call mysql_ping but this is ancient PHP version. Faking it!\n" );
2030                         return true;
2031                 }
2032                 $ping = mysql_ping( $this->mConn );
2033                 if ( $ping ) {
2034                         return true;
2035                 }
2036
2037                 // Need to reconnect manually in MySQL client 5.0.13+
2038                 if ( version_compare( mysql_get_client_info(), '5.0.13', '>=' ) ) {
2039                         mysql_close( $this->mConn );
2040                         $this->mOpened = false;
2041                         $this->mConn = false;
2042                         $this->open( $this->mServer, $this->mUser, $this->mPassword, $this->mDBname );
2043                         return true;
2044                 }
2045                 return false;
2046         }
2047
2048         /**
2049          * Get slave lag.
2050          * At the moment, this will only work if the DB user has the PROCESS privilege
2051          */
2052         function getLag() {
2053                 if ( !is_null( $this->mFakeSlaveLag ) ) {
2054                         wfDebug( "getLag: fake slave lagged {$this->mFakeSlaveLag} seconds\n" );
2055                         return $this->mFakeSlaveLag;
2056                 }
2057                 $res = $this->query( 'SHOW PROCESSLIST' );
2058                 # Find slave SQL thread
2059                 while ( $row = $this->fetchObject( $res ) ) {
2060                         /* This should work for most situations - when default db
2061                          * for thread is not specified, it had no events executed,
2062                          * and therefore it doesn't know yet how lagged it is.
2063                          *
2064                          * Relay log I/O thread does not select databases.
2065                          */
2066                         if ( $row->User == 'system user' &&
2067                                 $row->State != 'Waiting for master to send event' &&
2068                                 $row->State != 'Connecting to master' &&
2069                                 $row->State != 'Queueing master event to the relay log' &&
2070                                 $row->State != 'Waiting for master update' &&
2071                                 $row->State != 'Requesting binlog dump'
2072                                 ) {
2073                                 # This is it, return the time (except -ve)
2074                                 if ( $row->Time > 0x7fffffff ) {
2075                                         return false;
2076                                 } else {
2077                                         return $row->Time;
2078                                 }
2079                         }
2080                 }
2081                 return false;
2082         }
2083
2084         /**
2085          * Get status information from SHOW STATUS in an associative array
2086          */
2087         function getStatus($which="%") {
2088                 $res = $this->query( "SHOW STATUS LIKE '{$which}'" );
2089                 $status = array();
2090                 while ( $row = $this->fetchObject( $res ) ) {
2091                         $status[$row->Variable_name] = $row->Value;
2092                 }
2093                 return $status;
2094         }
2095
2096         /**
2097          * Return the maximum number of items allowed in a list, or 0 for unlimited.
2098          */
2099         function maxListLen() {
2100                 return 0;
2101         }
2102
2103         function encodeBlob($b) {
2104                 return $b;
2105         }
2106
2107         function decodeBlob($b) {
2108                 return $b;
2109         }
2110
2111         /**
2112          * Override database's default connection timeout.
2113          * May be useful for very long batch queries such as
2114          * full-wiki dumps, where a single query reads out
2115          * over hours or days.
2116          * @param int $timeout in seconds
2117          */
2118         public function setTimeout( $timeout ) {
2119                 $this->query( "SET net_read_timeout=$timeout" );
2120                 $this->query( "SET net_write_timeout=$timeout" );
2121         }
2122
2123         /**
2124          * Read and execute SQL commands from a file.
2125          * Returns true on success, error string or exception on failure (depending on object's error ignore settings)
2126          * @param string $filename File name to open
2127          * @param callback $lineCallback Optional function called before reading each line
2128          * @param callback $resultCallback Optional function called for each MySQL result
2129          */
2130         function sourceFile( $filename, $lineCallback = false, $resultCallback = false ) {
2131                 $fp = fopen( $filename, 'r' );
2132                 if ( false === $fp ) {
2133                         throw new MWException( "Could not open \"{$filename}\".\n" );
2134                 }
2135                 $error = $this->sourceStream( $fp, $lineCallback, $resultCallback );
2136                 fclose( $fp );
2137                 return $error;
2138         }
2139
2140         /**
2141          * Read and execute commands from an open file handle
2142          * Returns true on success, error string or exception on failure (depending on object's error ignore settings)
2143          * @param string $fp File handle
2144          * @param callback $lineCallback Optional function called before reading each line
2145          * @param callback $resultCallback Optional function called for each MySQL result
2146          */
2147         function sourceStream( $fp, $lineCallback = false, $resultCallback = false ) {
2148                 $cmd = "";
2149                 $done = false;
2150                 $dollarquote = false;
2151
2152                 while ( ! feof( $fp ) ) {
2153                         if ( $lineCallback ) {
2154                                 call_user_func( $lineCallback );
2155                         }
2156                         $line = trim( fgets( $fp, 1024 ) );
2157                         $sl = strlen( $line ) - 1;
2158
2159                         if ( $sl < 0 ) { continue; }
2160                         if ( '-' == $line{0} && '-' == $line{1} ) { continue; }
2161
2162                         ## Allow dollar quoting for function declarations
2163                         if (substr($line,0,4) == '$mw$') {
2164                                 if ($dollarquote) {
2165                                         $dollarquote = false;
2166                                         $done = true;
2167                                 }
2168                                 else {
2169                                         $dollarquote = true;
2170                                 }
2171                         }
2172                         else if (!$dollarquote) {
2173                                 if ( ';' == $line{$sl} && ($sl < 2 || ';' != $line{$sl - 1})) {
2174                                         $done = true;
2175                                         $line = substr( $line, 0, $sl );
2176                                 }
2177                         }
2178
2179                         if ( '' != $cmd ) { $cmd .= ' '; }
2180                         $cmd .= "$line\n";
2181
2182                         if ( $done ) {
2183                                 $cmd = str_replace(';;', ";", $cmd);
2184                                 $cmd = $this->replaceVars( $cmd );
2185                                 $res = $this->query( $cmd, __METHOD__ );
2186                                 if ( $resultCallback ) {
2187                                         call_user_func( $resultCallback, $res, $this );
2188                                 }
2189
2190                                 if ( false === $res ) {
2191                                         $err = $this->lastError();
2192                                         return "Query \"{$cmd}\" failed with error code \"$err\".\n";
2193                                 }
2194
2195                                 $cmd = '';
2196                                 $done = false;
2197                         }
2198                 }
2199                 return true;
2200         }
2201
2202
2203         /**
2204          * Replace variables in sourced SQL
2205          */
2206         protected function replaceVars( $ins ) {
2207                 $varnames = array(
2208                         'wgDBserver', 'wgDBname', 'wgDBintlname', 'wgDBuser',
2209                         'wgDBpassword', 'wgDBsqluser', 'wgDBsqlpassword',
2210                         'wgDBadminuser', 'wgDBadminpassword', 'wgDBTableOptions',
2211                 );
2212
2213                 // Ordinary variables
2214                 foreach ( $varnames as $var ) {
2215                         if( isset( $GLOBALS[$var] ) ) {
2216                                 $val = addslashes( $GLOBALS[$var] ); // FIXME: safety check?
2217                                 $ins = str_replace( '{$' . $var . '}', $val, $ins );
2218                                 $ins = str_replace( '/*$' . $var . '*/`', '`' . $val, $ins );
2219                                 $ins = str_replace( '/*$' . $var . '*/', $val, $ins );
2220                         }
2221                 }
2222
2223                 // Table prefixes
2224                 $ins = preg_replace_callback( '/\/\*(?:\$wgDBprefix|_)\*\/([a-zA-Z_0-9]*)/',
2225                         array( &$this, 'tableNameCallback' ), $ins );
2226                 return $ins;
2227         }
2228
2229         /**
2230          * Table name callback
2231          * @private
2232          */
2233         protected function tableNameCallback( $matches ) {
2234                 return $this->tableName( $matches[1] );
2235         }
2236
2237         /*
2238          * Build a concatenation list to feed into a SQL query
2239         */
2240         function buildConcat( $stringList ) {
2241                 return 'CONCAT(' . implode( ',', $stringList ) . ')';
2242         }
2243
2244         /**
2245          * Acquire a lock
2246          *
2247          * Abstracted from Filestore::lock() so child classes can implement for
2248          * their own needs.
2249          *
2250          * @param string $lockName Name of lock to aquire
2251          * @param string $method Name of method calling us
2252          * @return bool
2253          */
2254         public function lock( $lockName, $method ) {
2255                 $lockName = $this->addQuotes( $lockName );
2256                 $result = $this->query( "SELECT GET_LOCK($lockName, 5) AS lockstatus", $method );
2257                 $row = $this->fetchObject( $result );
2258                 $this->freeResult( $result );
2259
2260                 if( $row->lockstatus == 1 ) {
2261                         return true;
2262                 } else {
2263                         wfDebug( __METHOD__." failed to acquire lock\n" );
2264                         return false;
2265                 }
2266         }
2267         /**
2268          * Release a lock.
2269          *
2270          * @todo fixme - Figure out a way to return a bool
2271          * based on successful lock release.
2272          *
2273          * @param string $lockName Name of lock to release
2274          * @param string $method Name of method calling us
2275          */
2276         public function unlock( $lockName, $method ) {
2277                 $lockName = $this->addQuotes( $lockName );
2278                 $result = $this->query( "SELECT RELEASE_LOCK($lockName)", $method );
2279                 $this->freeResult( $result );
2280         }
2281
2282         /**
2283          * Get search engine class. All subclasses of this
2284          * need to implement this if they wish to use searching.
2285          *
2286          * @return string
2287          */
2288         public function getSearchEngine() {
2289                 return "SearchMySQL";
2290         }
2291 }
2292
2293 /**
2294  * Database abstraction object for mySQL
2295  * Inherit all methods and properties of Database::Database()
2296  *
2297  * @ingroup Database
2298  * @see Database
2299  */
2300 class DatabaseMysql extends Database {
2301         # Inherit all
2302 }
2303
2304 /******************************************************************************
2305  * Utility classes
2306  *****************************************************************************/
2307
2308 /**
2309  * Utility class.
2310  * @ingroup Database
2311  */
2312 class DBObject {
2313         public $mData;
2314
2315         function DBObject($data) {
2316                 $this->mData = $data;
2317         }
2318
2319         function isLOB() {
2320                 return false;
2321         }
2322
2323         function data() {
2324                 return $this->mData;
2325         }
2326 }
2327
2328 /**
2329  * Utility class
2330  * @ingroup Database
2331  *
2332  * This allows us to distinguish a blob from a normal string and an array of strings
2333  */
2334 class Blob {
2335         private $mData;
2336         function __construct($data) {
2337                 $this->mData = $data;
2338         }
2339         function fetch() {
2340                 return $this->mData;
2341         }
2342 }
2343
2344 /**
2345  * Utility class.
2346  * @ingroup Database
2347  */
2348 class MySQLField {
2349         private $name, $tablename, $default, $max_length, $nullable,
2350                 $is_pk, $is_unique, $is_multiple, $is_key, $type;
2351         function __construct ($info) {
2352                 $this->name = $info->name;
2353                 $this->tablename = $info->table;
2354                 $this->default = $info->def;
2355                 $this->max_length = $info->max_length;
2356                 $this->nullable = !$info->not_null;
2357                 $this->is_pk = $info->primary_key;
2358                 $this->is_unique = $info->unique_key;
2359                 $this->is_multiple = $info->multiple_key;
2360                 $this->is_key = ($this->is_pk || $this->is_unique || $this->is_multiple);
2361                 $this->type = $info->type;
2362         }
2363
2364         function name() {
2365                 return $this->name;
2366         }
2367
2368         function tableName() {
2369                 return $this->tableName;
2370         }
2371
2372         function defaultValue() {
2373                 return $this->default;
2374         }
2375
2376         function maxLength() {
2377                 return $this->max_length;
2378         }
2379
2380         function nullable() {
2381                 return $this->nullable;
2382         }
2383
2384         function isKey() {
2385                 return $this->is_key;
2386         }
2387
2388         function isMultipleKey() {
2389                 return $this->is_multiple;
2390         }
2391
2392         function type() {
2393                 return $this->type;
2394         }
2395 }
2396
2397 /******************************************************************************
2398  * Error classes
2399  *****************************************************************************/
2400
2401 /**
2402  * Database error base class
2403  * @ingroup Database
2404  */
2405 class DBError extends MWException {
2406         public $db;
2407
2408         /**
2409          * Construct a database error
2410          * @param Database $db The database object which threw the error
2411          * @param string $error A simple error message to be used for debugging
2412          */
2413         function __construct( Database &$db, $error ) {
2414                 $this->db =& $db;
2415                 parent::__construct( $error );
2416         }
2417 }
2418
2419 /**
2420  * @ingroup Database
2421  */
2422 class DBConnectionError extends DBError {
2423         public $error;
2424
2425         function __construct( Database &$db, $error = 'unknown error' ) {
2426                 $msg = 'DB connection error';
2427                 if ( trim( $error ) != '' ) {
2428                         $msg .= ": $error";
2429                 }
2430                 $this->error = $error;
2431                 parent::__construct( $db, $msg );
2432         }
2433
2434         function useOutputPage() {
2435                 // Not likely to work
2436                 return false;
2437         }
2438
2439         function useMessageCache() {
2440                 // Not likely to work
2441                 return false;
2442         }
2443
2444         function getText() {
2445                 return $this->getMessage() . "\n";
2446         }
2447
2448         function getLogMessage() {
2449                 # Don't send to the exception log
2450                 return false;
2451         }
2452
2453         function getPageTitle() {
2454                 global $wgSitename;
2455                 return "$wgSitename has a problem";
2456         }
2457
2458         function getHTML() {
2459                 global $wgTitle, $wgUseFileCache, $title, $wgInputEncoding;
2460                 global $wgSitename, $wgServer, $wgMessageCache;
2461
2462                 # I give up, Brion is right. Getting the message cache to work when there is no DB is tricky.
2463                 # Hard coding strings instead.
2464
2465                 $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>";
2466                 $mainpage = 'Main Page';
2467                 $searchdisabled = <<<EOT
2468 <p style="margin: 1.5em 2em 1em">$wgSitename search is disabled for performance reasons. You can search via Google in the meantime.
2469 <span style="font-size: 89%; display: block; margin-left: .2em">Note that their indexes of $wgSitename content may be out of date.</span></p>',
2470 EOT;
2471
2472                 $googlesearch = "
2473 <!-- SiteSearch Google -->
2474 <FORM method=GET action=\"http://www.google.com/search\">
2475 <TABLE bgcolor=\"#FFFFFF\"><tr><td>
2476 <A HREF=\"http://www.google.com/\">
2477 <IMG SRC=\"http://www.google.com/logos/Logo_40wht.gif\"
2478 border=\"0\" ALT=\"Google\"></A>
2479 </td>
2480 <td>
2481 <INPUT TYPE=text name=q size=31 maxlength=255 value=\"$1\">
2482 <INPUT type=submit name=btnG VALUE=\"Google Search\">
2483 <font size=-1>
2484 <input type=hidden name=domains value=\"$wgServer\"><br /><input type=radio name=sitesearch value=\"\"> WWW <input type=radio name=sitesearch value=\"$wgServer\" checked> $wgServer <br />
2485 <input type='hidden' name='ie' value='$2'>
2486 <input type='hidden' name='oe' value='$2'>
2487 </font>
2488 </td></tr></TABLE>
2489 </FORM>
2490 <!-- SiteSearch Google -->";
2491                 $cachederror = "The following is a cached copy of the requested page, and may not be up to date. ";
2492
2493                 # No database access
2494                 if ( is_object( $wgMessageCache ) ) {
2495                         $wgMessageCache->disable();
2496                 }
2497
2498                 if ( trim( $this->error ) == '' ) {
2499                         $this->error = $this->db->getProperty('mServer');
2500                 }
2501
2502                 $text = str_replace( '$1', $this->error, $noconnect );
2503                 $text .= wfGetSiteNotice();
2504
2505                 if($wgUseFileCache) {
2506                         if($wgTitle) {
2507                                 $t =& $wgTitle;
2508                         } else {
2509                                 if($title) {
2510                                         $t = Title::newFromURL( $title );
2511                                 } elseif (@/**/$_REQUEST['search']) {
2512                                         $search = $_REQUEST['search'];
2513                                         return $searchdisabled .
2514                                           str_replace( array( '$1', '$2' ), array( htmlspecialchars( $search ),
2515                                           $wgInputEncoding ), $googlesearch );
2516                                 } else {
2517                                         $t = Title::newFromText( $mainpage );
2518                                 }
2519                         }
2520
2521                         $cache = new HTMLFileCache( $t );
2522                         if( $cache->isFileCached() ) {
2523                                 // @todo, FIXME: $msg is not defined on the next line.
2524                                 $msg = '<p style="color: red"><b>'.$msg."<br />\n" .
2525                                         $cachederror . "</b></p>\n";
2526
2527                                 $tag = '<div id="article">';
2528                                 $text = str_replace(
2529                                         $tag,
2530                                         $tag . $msg,
2531                                         $cache->fetchPageText() );
2532                         }
2533                 }
2534
2535                 return $text;
2536         }
2537 }
2538
2539 /**
2540  * @ingroup Database
2541  */
2542 class DBQueryError extends DBError {
2543         public $error, $errno, $sql, $fname;
2544
2545         function __construct( Database &$db, $error, $errno, $sql, $fname ) {
2546                 $message = "A database error has occurred\n" .
2547                   "Query: $sql\n" .
2548                   "Function: $fname\n" .
2549                   "Error: $errno $error\n";
2550
2551                 parent::__construct( $db, $message );
2552                 $this->error = $error;
2553                 $this->errno = $errno;
2554                 $this->sql = $sql;
2555                 $this->fname = $fname;
2556         }
2557
2558         function getText() {
2559                 if ( $this->useMessageCache() ) {
2560                         return wfMsg( 'dberrortextcl', htmlspecialchars( $this->getSQL() ),
2561                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) ) . "\n";
2562                 } else {
2563                         return $this->getMessage();
2564                 }
2565         }
2566
2567         function getSQL() {
2568                 global $wgShowSQLErrors;
2569                 if( !$wgShowSQLErrors ) {
2570                         return $this->msg( 'sqlhidden', 'SQL hidden' );
2571                 } else {
2572                         return $this->sql;
2573                 }
2574         }
2575
2576         function getLogMessage() {
2577                 # Don't send to the exception log
2578                 return false;
2579         }
2580
2581         function getPageTitle() {
2582                 return $this->msg( 'databaseerror', 'Database error' );
2583         }
2584
2585         function getHTML() {
2586                 if ( $this->useMessageCache() ) {
2587                         return wfMsgNoDB( 'dberrortext', htmlspecialchars( $this->getSQL() ),
2588                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) );
2589                 } else {
2590                         return nl2br( htmlspecialchars( $this->getMessage() ) );
2591                 }
2592         }
2593 }
2594
2595 /**
2596  * @ingroup Database
2597  */
2598 class DBUnexpectedError extends DBError {}
2599
2600
2601 /**
2602  * Result wrapper for grabbing data queried by someone else
2603  * @ingroup Database
2604  */
2605 class ResultWrapper implements Iterator {
2606         var $db, $result, $pos = 0, $currentRow = null;
2607
2608         /**
2609          * Create a new result object from a result resource and a Database object
2610          */
2611         function ResultWrapper( $database, $result ) {
2612                 $this->db = $database;
2613                 if ( $result instanceof ResultWrapper ) {
2614                         $this->result = $result->result;
2615                 } else {
2616                         $this->result = $result;
2617                 }
2618         }
2619
2620         /**
2621          * Get the number of rows in a result object
2622          */
2623         function numRows() {
2624                 return $this->db->numRows( $this->result );
2625         }
2626
2627         /**
2628          * Fetch the next row from the given result object, in object form.
2629          * Fields can be retrieved with $row->fieldname, with fields acting like
2630          * member variables.
2631          *
2632          * @param $res SQL result object as returned from Database::query(), etc.
2633          * @return MySQL row object
2634          * @throws DBUnexpectedError Thrown if the database returns an error
2635          */
2636         function fetchObject() {
2637                 return $this->db->fetchObject( $this->result );
2638         }
2639
2640         /**
2641          * Fetch the next row from the given result object, in associative array
2642          * form.  Fields are retrieved with $row['fieldname'].
2643          *
2644          * @param $res SQL result object as returned from Database::query(), etc.
2645          * @return MySQL row object
2646          * @throws DBUnexpectedError Thrown if the database returns an error
2647          */
2648         function fetchRow() {
2649                 return $this->db->fetchRow( $this->result );
2650         }
2651
2652         /**
2653          * Free a result object
2654          */
2655         function free() {
2656                 $this->db->freeResult( $this->result );
2657                 unset( $this->result );
2658                 unset( $this->db );
2659         }
2660
2661         /**
2662          * Change the position of the cursor in a result object
2663          * See mysql_data_seek()
2664          */
2665         function seek( $row ) {
2666                 $this->db->dataSeek( $this->result, $row );
2667         }
2668
2669         /*********************
2670          * Iterator functions
2671          * Note that using these in combination with the non-iterator functions
2672          * above may cause rows to be skipped or repeated.
2673          */
2674
2675         function rewind() {
2676                 if ($this->numRows()) {
2677                         $this->db->dataSeek($this->result, 0);
2678                 }
2679                 $this->pos = 0;
2680                 $this->currentRow = null;
2681         }
2682
2683         function current() {
2684                 if ( is_null( $this->currentRow ) ) {
2685                         $this->next();
2686                 }
2687                 return $this->currentRow;
2688         }
2689
2690         function key() {
2691                 return $this->pos;
2692         }
2693
2694         function next() {
2695                 $this->pos++;
2696                 $this->currentRow = $this->fetchObject();
2697                 return $this->currentRow;
2698         }
2699
2700         function valid() {
2701                 return $this->current() !== false;
2702         }
2703 }
2704
2705 class MySQLMasterPos {
2706         var $file, $pos;
2707
2708         function __construct( $file, $pos ) {
2709                 $this->file = $file;
2710                 $this->pos = $pos;
2711         }
2712
2713         function __toString() {
2714                 return "{$this->file}/{$this->pos}";
2715         }
2716 }